thesis

THESIS 

INFLUENCE OF HARVEST TIME AND STORAGE 

TEMPERATURE ON CHARACTERISTICS OF INULIN FROM 

JERUSALEM ARTICHOKE AND PHYSICOCHEMICAL 

PROPERTIES OF INULIN-STARCH MIXED GEL 

WANPEN SAENGTHONGPINIT 

A Thesis Submitted in Partial Fulfillment of 

the Requirement for the Degree of 

Doctor of Philosophy (Food Science) 

Graduate School, Kasetsart University 

2005 

ISBN 974-9834-71-2

ACKNOWLEDGEMENTS 

I would like to express my sincere gratitude and very appreciation to my advisor, Dr. 

Tanaboon Sajjaanantakul for his kindness, guidance, encouragement and constructive 

criticism throughout the study, which enable me to carry out this thesis successfully. 

I am also grateful to my committees, Asst. Prof. Dr. Sanguansri Charoenrien and 

Assoc. Prof. Dr. Sarote Sirisansaneeyakul for their kindness, valuable comments and 

suggestions. 

Grateful acknowledgement and sincere appreciation are extended to Prof. Dr. James 

N. BeMiller, former director of Whistler Center for Carbohydrate Research, Department of 

Food Science, Purdue University for his kindness, guidance, take care and give me an 

opportunity and financial support to do my research at Whistler Center for Carbohydrate 

Research. 

Special thanks are extended to Dr. Wirat Vanichsriratana, who kindly served as a 

thesis graduate committee chairman and provides valuable comments. I am also thank Mr. 

Prapart Changlek from Research and development Institute for Agricultural Systems Under 

Adverse Conditions, Kasetsart University for providing the Jerusalem artichoke tubers. 

In particular I would like to thank all staff member of Food Science and Technology 

for their assistance. I am also thank all my friends for their encouragement. 

Deep appreciation is likewise extended to the Phetchaburi Rajabhat University for 

education scholarship. Also, thank Postgraduate Education and Research Development in 

Postharvest Technology Program, Kasetsart University, the Split-mode program, National 

Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand, Graduate school of 

Kasetsart University for their research fund. 

Finally, I express the most gratitude to my husband, Mr. Chalermkiat Saengthongpinit 

for his support and affection and also my family for their love, understanding, 

encouragement, moral support and confidence in me. 

Wanpen Saengthongpinit 

August 2005

TABLE OF CONTENTS 

i 

Page 

TABLE OF CONTENTS i 

LIST OF TABLES iii 

LIST OF FIGURES viii 

INTRODUCTION……………………………………………………………………………..1 

Objectives..……………………………………………………………………………3 

LITERATURE REVIEWS………………………………………………………………….…4 

Fructan Structure and Chemistry……………………………………………………...4 

Sources of Fructan and Inulin…………………………………………………………7 

Jerusalem artichoke (Helianthus tuberosus L.)…………………………………….…9 

Sunflower Head……………………………………………………………………...13 

Harvest Time and Storage Condition on Quality of Jerusalem Artichoke…………..13 

Extraction and Processing of Inulin from Inulin Containing Plant………………….16 

Inulin Precipitation…………………………………………………………………..19 

Analytical Method for Inulin………..……………………………………………….21 

Inulin Properties……………………………………………………………………...24 

Hylon (High Amylose Starch) and Amioca (High Amylopectin Starch)……………33 

Mixed Polysaccharide Gels………………………………………………………….38 

Viscoelastic Measurement for Rheological Prpperties..…………………………….40 

Modulated Differential Scanning Calorimetry……………………………………....46 

MATERIALS AND METHODS..……………………………………………………………48 

Materials……………………………………………………………………………..48 

Methods……………………………………………………………………………...50 

RESULTS AND DISCUSSIONS…………………………………………………………….62 

Effect of Harvest Time on Jerusalem Artichoke Inulin.……………………………..62 

Effect of Storage Temperature on Jerusalem Artichoke Inulin.……………………..66 

Effect of Storage Time on Jerusalem Artichoke Inulin.……………………………..72 

Inulin Extraction from Dried Sunflower Head……………………………………....83 

Effect of Solvent Extraction on Inulin Composition of Jerusalem Artichoke…..…...86 

Effect of Solvent on Inulin Precipitation…………………………………………….94 

Physicochemical Properties of inulin gel and Mixed gel…………………………..106 

CONCLUSION……………………………………………………………………………..153

TABLE OF CONTENTS (cont’d) 

ii 

Page 

LITERATURE CITED……………………………………………………………………...155 

APPENDIX……………………………………………………………………………….…169

LIST OF TABLES 

Table Page 

1 Natural occurance of inulin and oligofructose………………………………………...9 

2 Describing the inulin in Jerusalem artichoke………………………………………...12 

3 Physicochemical properties of chicory inulin………………………………………..25 

4 Freezing and boiling point of inulin solution..……………………………………….27 

5 Food application of inulin……………………..……………………………………..28 

6 Biological and nutritional properties of inulin……………………………………….29 

7 Rheological properties of amylose and amylopectin………………………………...37 

8 Parameters that can be determined by oscillatory shear testing……………………..42 

9 Dry matter, total soluble solids and relative percentage composition 

of sugars and inulin of Jerusalem artichoke tubers with different maturity…………63 

10 Dry matter and total solid of 21-weeks maturity first crop Jerusalem 

artichoke tubers stored at different temperatures for 12 weeks……………………...67 

11 Relative percentage of sugar and inulin composition of 21-weeks maturity first 

crop Jerusalem artichoke tubers stored at different temperature for 12 weeks….…..69 

12 Relative percentage of sugar and inulin composition of 16-weeks maturity second 

crop Jerusalem artichoke tubers stored at different temperature for 12 weeks…..….69 


crop Jerusalem artichoke tubers stored at different temperature for 12 weeks……...70 


crop Jerusalem artichoke tubers stored at different temperature for 10 weeks…...…70 

15 Relative percentage of sugar and inulin composition of 21-weeks maturity 

frist crop Jerusalem artichoke tubers with different storage time at -18 o C………….72 


first crop Jerusalem artichoke tubers with different storage time at -40 o C..….……..73 


first crop Jerusalem artichoke tubers with different storage time at -2 o C..…….……74 


second crop Jerusalem artichoke tubers with different storage time at -18 o C…...…..74 


second crop Jerusalem artichoke tubers with different storage time at 2 o C…………75 


second crop Jerusalem artichoke tubers with different storage time at 5 o C………...75 

iii

LIST OF TABLES (cont’d) 

Table Page 


second crop Jerusalem artichoke tubers with different storage time at -18 o C………76 






second crop Jerusalem artichoke tubers with different storage time at -18 o C……….77 


second crop Jerusalem artichoke tubers with different storage time at 2 o C………....78 


second crop Jerusalem artichoke tubers with different storage time at 5 o C….……...78 

27 Relative percentage of inulo-n-ose as compared to sugar and inulin 

composition of 16-weeks maturity second crop Jerusalem artichoke tubers 

stored at 2 o C and 5 o C up to12 weeks………………………………………………..81 



stored at 2 o C and 5 o C up to12 weeks………………………………………………..82 



stored at 2 o C and 5 o C up to10 weeks……………………………………………….83 

30 Proximate composition of dried sunflower head……………………………………84 

31 Effect of solvent (water, 50% and 80% ethanol) on relative percent of sugar 

and inulin composition of Jerusalem artichoke tubers extracted for 15 min…...……88 

32 Effect of solvent (water, 50% and 80% ethanol) on relative percent of sugar 

and inulin composition of Jerusalem artichoke tubers extracted for 1 h…..…...……89 

33 Effect of solid: liquid ratio on relative percent of sugar and nulin composition of 

Jerusalem artichoke tubers which extracted by water….……………………………90 

34 Effect of solid: liquid ratio on relative percent of sugar and nulin composition of 

Jerusalem artichoke tubers which extracted by 50% ethanol……….……………….91 

35 Effect of solid: liquid ratio on relative percent of carbohydrate and inulin 

composition of Jerusalem artichoke which extracted by 80% ethanol………………92 

iv


Table Page 

36 Effect of solvent on relative percent of sugar and inulin composition of 

Jerusalem artichoke tubers…………………………………………………………..93 

37 Effect of solid: liquid ratio of 80% ethanol solventrto relative percent of 

sugar and inulin composition of Jerusalem artichoke tubers………………………...93 

38 The amount of dried inulin in precipitate fraction…………………………………...95 

39 Effect of final concentration and temperature on relative percent of sugar 

and inulin composition of precipitate………………………………………………...97 

40 Effect of final concentration and temperature on relative percent of sugar and 

inulin composition left in supernatant after the precipitate step for 1 day…….……..98 

41 Effect of final concentration and temperature on relative percent of second 

fructan found in the supernatant……………………………………………………...98 

42 Effect of precipitation method on relative percent of sugar and inulin 

composition of precipitate which precipitation at 4 o C for 5 day………………….....99 

43 Degree of gel formation and gel strength of inulin HP at different concentration....111 

44 Effect of inulin HP on pasting temperature, peak viscosity and final viscosity 

of gel by Rapid Visco-Analyser…………………………….………………………112 

45 Effect of inulin JAT on pasting temperature, peak viscosity and final viscosity 

of gel by Rapid Visco-Analyser…………………………………………….………113 

46 Textural preperties of inulin HP and inulin-starch mixed gel as calculated 

from force-time curve texture analyzer……………………………………………..122 

47 Thermal properties of inulin-starch mixed gel as analyzed by 

Modulated Differential Scanning Calorimetry……………………………………..149 

Appendix Table 

1 Result of Multivariate test of harvest time effect on inulin composition of 

16,18 and 20 weeks maturity second crop Jerusalem artichoke tubers…………….170 

2 The analysis result of the effect of of harvest time on inulin composition of 

16, 18 and 20 weeks maturity second crop Jerusalem artichoke tubers…………….171 

3 Result of Multivariate test of storage temperature effect on inulin composition 

of 21-weeks maturity first crop Jerusalem artichoke tubers…………………….….172 

v


Appendix Table Page 

4 The analysis result of the effect of storage temperature on inulin composition 

of 21-weeks maturity first crop Jerusalem artichoke tubers..………………………...173 


of 16-weeks maturity second crop Jerusalem artichoke tubers..……………………174 

6. The analysis result of the effect of storage temperature on inulin composition 

of 16-weeks maturity second crop Jerusalem artichoke tubers..…………………...175 

7. Result of Multivariate test of storage temperature effect on inulin composition 

of 18-weeks maturity second crop Jerusalem artichoke tubers……………………..176 


of 18-weeks maturity second crop Jerusalem artichoke tubers……………………..177 


of 20 weeks maturity second crop Jerusalem artichoke tubers……………………..178 


of 20-weeks maturity second crop Jerusalem artichoke tubers………………….….179 

11 Result of Multivariate test of storage temperature and time effect on inulin 

composition of 21-weeks maturity first crop Jerusalem artichoke tubers. ………...180 

12 The analysis result of the effect of storage temperature and time effect on inulin 

composition of 21-weeks maturity first crop Jerusalem artichoke tubers.…………181 


composition of 16-weeks maturity second crop Jerusalem artichoke tubers...……..182 


composition of 16-weeks maturity second crop Jerusalem artichoke tubers.………183 



16 The analysis result of the effect of storage temperature and time on inulin 

composition of 18-weeks maturity second crop Jerusalem artichoke tubers.……....185 





19 Result of Multivariate test of the effect of solvent extraction on inulin 

composition…….……………………………………………………………………189 

vi


Appendix Table Page 

20 The analysis result of the effect of solvent extraction on inulin composition……...190 

21 Result of Multivariate test of inulin precipitate method effect on inulin yield……..192 

22 The analysis result of the effect of inulin precipitate method on inulin yield……...192 

23 Result of Multivariate test of inulin precipitate with different solvent 

effect on inulin composition at 4 o C…………………………………………………193 

24 Result of Multivariate test of inulin precipitate with different solvent effect on 

inulin composition at 25 o C………………………………………………………….193 

25 The analysis result of the effect on inulin composition of inulin precipitate with 

different solvent at 4 o C……………………………………………………………..193 

26 The analysis result of the effect on inulin composition of inulin precipitate 

with different solvent at 25 o C………………………………………………………195 

27 Result of Multivariate test of inulin precipitate with different solvent at 4 o C 

effect on inulin composition in supernatant………………………………………..196 

28 Result of Multivariate test of inulin precipitate with different solvent 

at 25 o C effect on inulin composition in supernatant………………………………..196 

29 The analysis result of the effect of inulin precipitate with different solvent 

at 4 o C effect on inulin composition in supernatant…………………………………197 

30 The analysis result of the effect of inulin precipitate with different solvent 

at 25 o C effect on inulin composition in supernatant………………………………..198 

vii

LIST OF FIGURES 

Figure Page 

1 Structure of the fructans with their established names…………………………….….5 

2 Cumulative distribution of polydisperse inulin of fresh plant material……………….8 

3 Process flow-sheet for the production of fructose, 

inulo-oligosaccharides and inulin……………………………………………………17 

4. Oxyanion of carbohydrate in alkaline condition……………………………………..21 

5 Structure of pellicular ion exchange packing for high resolution 

carbohydrate separations……………………………………………………….……22 

6 Ion exchange separations are base on the analyze ions in competition 

with the eluent ion for the same exchange sites……………………………………...23 

7 Schematic models for two-compenents mixed gel network………………………....40 

8 Variation of the phase lag (δ) with frequency (ω) for typical materials……………..43 

9 Typical response to a strain or stress sweep showing the linear viscoelastic 

region defined by the critical value of the sweep parameter…………………….…...44 

10 Inulin extraction process diagram……………………………………………………54 

11 Definition of VGI…………………………………………………………………….56 

12 Controlled strain rheometer with speed plate-plate cell……………………………...60 

13 Jerusalem artichoke stems and tubers………………………………………………..62 

14 Spongy texture of 20-weeks tubers……………………………………………….….66 

15 Relative percentage (mean + SD) of sugars and inulin profiles from 20-weeks 

maturity Jerusalem artichoke tubers…………………………………………………68 

16 HPAEC-PAD Chromatograms of inulin and new fructan series from 

20-week maturity Jerusalem artichoke tubers as fresh tuber……….………….…….71 

17 HPAEC-PAD chromatograms of inulin extracted from 18-weeks maturity 

Jerusalem artichoke tubers and stored at 2 o C for 8 weeks, which demonstrate 

the new fructan series………………………………………………………………...80 

18 Dried de-seed sunflower head………………………………………………………..84 

19 HPAEC-PAD chromatograms of carbohydrate extracted from sunflower head……..85 

20 HPAEC-PAD chromatogram of DP distribution profile of inulin precipitation 

by water and different final ethanol concentration at 4 o C and 25 o C……………….101 

21 HPAEC-PAD chromatogram of DP distribution profile of supernatant 

by water and different final ethanol concentration at 4 o C and 25 o C ……………….104 

viii

LIST OF FIGURES (cont’d) 

Figure Page 

22 Effect of tempearature on solubility of commercial inulin Raftiline HP 

(inulin HP) and inulin from jerusalem artichoke (inulin JAT)……………………..108 

23 Sol-Gel transition of inulin solution 25% (w/v) heated at 80 o C for 5 min 

and cooled down at 20 o C for 1 days………………………………………………..109 

24 Gel formation of inulin HP solution at different concentration (%, w/v) 

heated at 80 o C for 5 min and cooled down at 20 o C for 1 days……………………..110 

25 Pasting curves of inulin and inulin-hylon mixed gel……………………………….114 

26 Pasting curves of inulin-corn mixed gel……………………………………………115 

27 Pasting curves of inulin-amioca mixed gel…………………………………………116 

28 Effect of inulin on viscosity reduction of inulin-starch mixed gel…………………117 

29 Photomicrographs of hylon starch granules………………………………………..118 

30 Force-time curves of inulin-starch mixed gel………………………………………121 

31 Scanning electron microscopy of inulin and inulin-starch mixed gel……………...125 

32 Photomicrographs of inulin HP gel………………………………………………...126 

33 Photomicrographs of hylon gel…………………………………………….………126 

34 Photomicrographs of inulin-hylon gel……………………………………………..126 

35 Steady shear characterized apparent viscosity of inulin HP 25% (w/w) 

solution at different temperature as function of shear rate…………………………128 

36 Steady shear characterized apparent viscosity of inulin HP solution at 

different concentration as function of decreasing a (cool down) temperature……...128 

37 Temperature sweep demonstrated sol-gel transition on inulin HP 25% (w/w); 

measured at constant frequency at 1 Hz with 1% strain and 0.5% strain…………..130 

38 Dynamic rheological data for storage modulus in strain sweep at different 

temperature of hylon and inulin HP-hylon mixed gel at 1 Hz frequency…………..133 

39 Dynamic rheological data for modulus in frequency sweep at different 

temperature of hylon and inulin HP-hylon mixed gel at 0.001 (0.1%) strain 

and 1 Hz frequency…………………………………………………………………134 

40 Dynamic rheological data for effect of temperature on modulus at a total 

polymer concentration 20% (w/w) of hylon and inulin HP-hylon mixed gel 

at 0.001 (0.1 %) strain and at 1 Hz frequency………………………………………135 

ix

LIST OF FIGURES (cont’d) 

Figure Page 

41 Dynamic rheological data for effect of temperature on tan δ (phase angel) 

at a total polymer concentration 20% (w/w) of hylon and inulin HP-hylon 

mixed gel at 0.001 (0.1%) strain and at 1 Hz frequency……………………………136 

42 Dynamic rheological data of storage modulus in strain sweep at different 

temperature of corn and inulin HP-corn mixed gel at 1 Hz frequency……………..138 

43 Dynamic rheological data of modulus in frequency sweep at different 

temperature of corn and inulin HP-corn mixed gel at 0.02 (2%) strain…………….139 

44 Dynamic rheological data for effect of temperature on modulus at a total 

polymer concentration 8% (w/w) corn and inulin HP-corn mixed at 

0.02 (2%) strain and at 1 Hz frequency…………………………………………….140 


at a total polymer concentration 8% (w/w) corn and inulin HP-corn mixed 

gel at 0.02 (2%) strain and at 1 Hz frequency………………………………………140 

46 Dynamic rheological data of storage modulus in strain sweep at different 

temperature of amioca and inulin HP-amioca mixed gel at 1 Hz frquency………...143 

47 Dynamic rheological data of modulus in frequency sweep at 20 o C of amioca 

and inulin HP-amioca mixed gel at 0.02 (2%) strain and at 1 Hz frquency………..144 

48 Dynamic rheological data of effect of temperature on modulus of amioca 

and inulin HP-amioca mixed gel at 0.02 (2%) strain and at 1 Hz frquency………..145 


at a total polymer concentration 15% (w/w) amioca and inulin HP-amioca 

mixed gel at 0.02 (2%) strain and at 1 Hz frequency……………………………….146 

50 MDSC thermogram of inulin HP gel which formed gel at room temperature 

for 1 day…………………………………………………………………………….150 

51 Total heat flow from MDSC thermogram of hylon (high amylose) starch gel 

and inulin HP-hylon mixed gel which formed gel at room temperature for 1 day...150 

52 Total heat flow from MDSC thermogram of amioca (high amylopectin), corn 

starch gel and inulin HP-amioca, inulin HP-corn and inulin HP-corn-amioca 

mixed gel which formed gel at room temperature for 1 day………………………..151 

x

INFLUENCE OF HARVEST TIME AND STORAGE TEMPERATURE ON 

CHARACTERISTICS OF INULIN FROM JERUSALEM ARTICHOKE AND 

PHYSICOCHEMICAL PROPERTIES OF INULIN-STARCH MIXED GEL 

INTRODUCTION 

Inulin is fructan which is non reducing water soluble carbohydrate found in higher 

plants. Inulin composes of fructosyl unit and usually containing one terminal glucose moiety 

per molecule. The fructose units are linked by β (2-1) linkage. The chain length or degree of 

polymerization (DP) of inulin range from 2 to 60 units, while oligofructose range from 2 to 10 

(Hoebregs, 1997; Coussement, 1999). Inulin occurs naturally as plant storage carbohydrates 

in a number of vegetables and plants including wheat, onion, banana, garlic, chicory and 

Jerusalem artichoke but two crops species, root chicory and Jerusalem artichoke have been 

grown for inulin production (Frese, 1993). Commercial inulin is obtained by synthesizing 

from sucrose or by hot water extracted from chicory roots ( Niness, 1999; Coussement, 1999; 

Cho and Prosky, 1999). 

Inulin as well as oligofructose is soluble dietary fiber, which resist to hydrolysis by 

human digestive enzyme. Moreover, when reaching the colon, both inulin and oligofructose 

are fermented and encourage growth of bifidobacteria which called bifidogenic factors as 

prebiotic properties and decrease colonic pH to reduced diarrhea and Salmonella (Izzo and 

Franck, 1998; Farnworth, 1994). 

The DP of inulin depends on many factors such as sources from which it was 

extracted, the climate and growing condition, the harvesting maturity and storage time after 

harvest (Coussement, 1999). The functional properties of inulin depend on its chain length. 

Inulin has longer chain length than oligofructose so it is less soluble and has the ability to 

form a smooth creamy texture gel at high concentration (Niness, 1999). Inulin is also an 

excellent fat replacer and forms a particle gel network after shearing. The gel strength 

depends on concentration, total dry substances and on the shearing parameters, but is not 

influence by pH. Water is immobilized in the net work, which assures the physical stability 

of the gel over the time. The net work exhibits a visco-elastic rheological behavior and shows 

shear-thinning properties (Chang, 2000). 

1

Inulin is used as substitutes for fat and sugar in ice cream for technological advantage 

include: stabilization, reduction of crystal growth during storage and improving creamy taste 

(Cho and Prosky, 1999; Schaller-Povolny and Smith 1999). Moreover, applications of inulin 

are showed in many products such as fermented dairy product, confectionery, chocolate, meat 

product, beverage, low fat spread, frozen dessert, breakfast cereal, fruit preparations and high 

fructose syrup productio (Orafti, 1998; Cho and Prosky, 1999). Inulin can be used in foods 

that contain starch but little knows about the interaction of starch and inulin. 

Jerusalem artichoke (Helianthus tuberosus) or sunchoke is in the same family with 

sunflower (Helianthus annus). It is the source of inulin, which has been range 16-39 %. In 

Thailand, Jerusalem artichoke had been grown in 1992 at Horticulture Department of 

Kasetsart University, Bangkhen campus which had unsuitable condition but it could be grown 

and gave moderate yield. Pinpong (1997) studied on growth and development quality, 

storage quality and harvesting index. In addition, he studied on effect of fertilization on yield 

and quality of Jerusalem artichoke tubers at The Royal Project Station, Pangda in Chiangmai. 

This research was studied for promotion Jerusalem artichoke to commercial crop. 

In 2001, Research and Development Institute for Agricultural Systems Under 

Adverse Conditions (IASAC), Kasetsart University studied Jerusalem artichoke for its 

potential on commerce and utilization. The utilization of Jerusalem artichoke tubers is of 

interested. It can be consumed as fresh vegetable and use as animal feed in swine and 

poultry. The most interesting utilization of Jerusalem artichoke is used as raw materials in 

inulin production. Therefore, study on quantity and quality change of inulin from Jerusalem 

artichoke of different maturity and storage condition is included with extraction of inulin with 

different type, liquid-solid ratio and time for beneficial to support industrial inulin production. 

Sunflower is in the same family with Jerusalem artichoke. In the present, sunflower 

heads are the wastes from sunflower seed production. So, it may be a potential source of 

inulin. 

2

OBJECTIVES 

The objectives of this research are to determine the optimum maturity and the 

appropriate storage condition of Jerusalem artichoke on quality of inulin from Jerusalem 

artichoke. In addition, this study evaluates the extraction and purification method of inulin. 

The characteristics physical properties, and behavior of inulin and its interaction with other 

hydrocolloids will also be investigated. The objectives also are to investigate whether 

sunflower head could be a potential source of inulin or not. 

Specific objectives 

1. To study the influence of harvest times and storage temperature on chain length, 

sugar profile of inulin from Jerusalem artichoke tubers grown in Thailand under tropical 

climate. 

2. To determine sugar profile of inulin from cultivars of sunflower head. 

3. To evaluate effect of solvent, solid-liquid ratio, and time for inulin extraction and 

inulin purification method. 

4. To study physicochemical properties of the extracted inulin and its combination 

with other food hydrocolloids such as high amylose or high amylopectin starch. 

Expected results 

1. Optimum harvest time of Jerusalem artichoke grown in Thailand for inulin 

quality. 

2. Appropriate storage condition of the harvested Jerusalem for optimum quality of 

inulin. 

3. Comparing quality of inulin from Jerusalem artichoke and dried sunflower head 

grown in Thailand. 

4. Proper extraction conditions and purification method of inulin from selected 

post-harvest condition of Jerusalem artichoke. 

5. Solubility and gel properties of commercial and extracted inulin. 

gel. 

6. Rheology and physicochemical properties of inulin gel and inulin-starch mixed 

3

1. Fructan Structure and Chemistry 

LITERATURE REVIEWS 

Fructan accumulation usually occurs in storage tissue of Jerusalem artichoke e.g. 

stem, crowns, tubers or roots. The quantity varies according to time of year and maturation. 

The older tissue composes less the storing of fructan (Housley and Pollock, 1993). Fructan is 

a compound composed of fructose (F) and some glucose (G) and one or more fructosylfructose 

linkages constitute majority of the linkages (Waterhouse and Chatterton, 1993). Four 

disaccharide units are found in various fructans: sucrose (G1↔2F), inulobiose (F2→1F), 

levanbiose (F2→6F) and unnamed molecule composed, like sucrose, but linked at O6 of 

glucose instead of O1 (F6→6G). The addition of one fructosyl residue to sucrose produces 1- 

kestose or iso-kestose (G1↔2F1←2F), 6-kestose or kestose (G1↔2F6←2F) and neokestose 

(F2←6G1↔2F) (Figure 1). All of these are non-reducing trisaccharides because the 

hydrogen atom of the OH group on C2 is replaced with other function group. However, there 

are a number of reducing trisaccharide including the linear inulotriose (F2↔1F2→1F) and 

levantriose (F2↔6F2→6F) (French and Waterhouse, 1993). Inulo-n-ose is oligomeric 

fructofuranosyl sugar that has all (2→1) linkage, i.e., inulobiose, inulotriose (Waterhouse and 

Chatterton, 1993). Inulobiose and levanbiose occur mostly as fragments after breakdown of 

large molecule. The total number of sugar residues present in a molecule is called its degree 

of polymerization (DPn) or number average degree of polymerization. 

1.1 Classification of fructan by linkage structure (Capita et al., 1989) 

1.1.1 Inulin has mostly or exclusively the β-D (2→1) fructosyl-fructose linkage 

(a glucose is allowed but is not necessary). Linear inulin implies (2→1) linkage exclusively. 

1.1.2 Levan/ Phlein has mostly or exclusively the β-D (2→6) fructosyl-fructose 

linkage (a glucose is allowed but is not necessary). Phlein is levan which used to describe 

plant-derived meterial. 

1.1.3 Graminan is high branched fructan which has both the β-D (2→1) and β-D 

(2→6) fructosyl-fructose linkage 

All fructans found in dicotyledons were of the inulin type. In monocotyledons, the 

phlein type occurred more frequently than the inulin type. Inulin type fructans forme 3,4,6- 

4

trimethyl-D-fructose after methylation and hydrolysis. The levan or phlein type fructans 

forme 1,3,4-trimethyl-D-fructose (Suzuki, 1993a). 

Figure 1 Structure of the fructans with their established names. 

Source: Van Loo et al.(1995) 

1.2 Definition of inulin 

The word inulin comes from Inula helanium, the source of a series of (2→1) 

linked furanose linked at the end to a glucose residue. Inulin is polydisperse fructan, which 

has DP 2-60 or more. In general, formation of inulin is GFn and Fn where G is glucose 

moiety, F is Fructose moiety and n is the number of fructose molecules. Lower polymer (DP 

2-60) is called fructo-oligosaccharide or fructo sugar or oligofructose. Fructo-oligosaccharide 

5

has two classes; fructosyl-fructose linkage with a glucose unit (GFn type) and only fructosylfructose 

linkage (Fn-type) (Roberfroid, 1993; Van Loo et al., 1995; Coussement, 1999). 

1.3 Fructan and inulin synthesis 

Inulin is stored in vacuoles of plant cell. As reported by Edelman and Jefford 

(1968) tuber growth and fructan synthesis in Jerusalem artichoke are controlled by sucrose : 

sucrose fructosyltransferase (SST) and fructan: fructan fructosyltransferase (FFT). SST is 

found in the first stage of inulin synthesis or during growing tubers and disappeared rapidly 

from the tissue when tubers stopped growing, while FFT activity is always present. SST can 

be isolated from growing tuber, where as FFT can be detected in mature tubers. A model for 

the synthesis and breakdown of fructan in Jerusalem artichoke has been proposed that the 

fructan synthesis proceeded via action of two fructosyltransferase with sucrose as the primary 

fructosyl donor in the vacuole (Edelman and Jefford,1968). Sucrose can be converted into 

fructans in leaves during darkness, indicating that sucrose can function as both substrate and 

energy source (Housley and Pollock, 1993). 

SST is cytoplasmic in location, and that FFT acts vectorially across the 

tonoplast, this despite pH optima of 5.0 to 5.2 for SST and 6.0-7.0 for FFT, optimum 

temperature is at 30 o C. Fructan mobilization in higher plants is mediated by the action of one 

or more exo-hydrolytic enzyme. The hydrolytic enzyme are classified as β-fructofuranodases 

(E.C. 3.2.1.26) or invertase and fructan exohydrolase (E.C. 3.2.1.80) (Housley and Pollock, 

1993). 

Sucrose: sucrose fructosyltransferase (SST, E.C.2.4.1.99) catalyzes the first step 

by the formation of 1-kestose: 

G-F + G-F → G-F-F + G 

Fructan : fructan fructosyltransferase (FFT, E.C.2.4.1.100) then utilizes the 1kestose 

as substrate for further chain elongation into inulin-type fructans: 

G-F-(F)n + G-F-(F)m ↔ G-F-(F)n+1 + G-F-(F)m-1 

6

The first step of fructan biosynthesis is assumed to be carried out by the SST 

which releases free glucose. Glucose therefore usually appears during inulin synthesis. The 

decrease of free glucose could indicate a decline of fructan synthesis in mature Jerusalem 

artichoke (Limami and Fiala, 1993). The relative abundance of chain length inulin depends on 

the relative affinity of the FFT with different inulin chain length. Distribution curves of DP 

from inulin metabolism modeling shows the most abundant polymers with chain length 

around DP 10. It is assumed that the affinity of FFT initially decreased, then increase with an 

increase in chain length (Shaw et al., 1993). 

3.2.1.80). 

Depolymerization of fructan is initiated by a fructan exohydrolase (FEH, E.C. 

G-F-(F)n → G-F-(F)n-1 +F 

FEH does not catalyze sucrose hydrolysis. Fructose is the product of FEH 

hydrolysis of fructan (Housley and Pollock, 1993). FEH activity exhibits Michaelis-Mentenlike 

kinetics. When FEH was incubated with inulin, the Km of the exo-hydrolase activity 

increased with the increase in degree of polymerization of inulin. Bonnett and Simpson 

(1993) found that the FEH exhibits higher affinity for fructans of lower DP. By contrast, the 

velocity of FEH activity, against fructan with mean DP ranging from 34 to 314 was 

influenced only by concentration and, not by DP. Pejin et al. (1993) suggested that 

hydrolysis of raw juice by Novo inulinase first led to degradation of high fructan polymer 

(DP>10) with the formation of D-fructose and fructo-oligosaccharides. The amount of free 

fructose increases in the mature root probably due to inulinase (E.C. 3.2.1.7) activity in the 

root (Limami and Fiala, 1993). 

2. Sources of Fructan and Inulin 

Fructan is storage carbohydrate in vacuole of plants and also occurrence in bacteria 

nd fungi. Sources of fructan are shown as following (Hendry and Wallace, 1993) 

2.1 Plants 

Fructan is storage carbohydrate in root, tuber, seed and stem parts. In 

monocotyledons, fructan are widely present in the grasses (Gramineae) and the Liliaceae e.g., 

garlic, onion, leek. Inulin in Liliaceae almost is low DP oligomer. Inulin in dicotyledons is 

7

present in high content in Compositae (Asteraceae) family e.g., chicory, Jerusalem artichoke 

and globe artichoke that contain high DP polymer. Each plant contain in different contents 

and DP fraction of inulin in Figure 2 and Table 1. Inulin also occurs in algae i.e. Acetabularia 

mediterranea. In higher plants, the DP of inulin ranges to as high as 70 residues (French and 

Waterhouse, 1993). 

Figure 2 Cumulative distribution of polydisperse inulin of fresh plant material 

Source: Van Loo et al. (1995) 

2.2 Fungi 

Utilization of fructans by yeast has been known for many years. One of the 

earliest report of fructans accumulation in fungi was in Aspergillus sydowi. The molecular 

weight of the inulin from Aspergillus sydowi is greater than that found in plants and is 

synthesized extracellurly from a sucrose source (French and Waterhouse, 1993). 

2.3 Bacteria 

Bacterial fructans are of the levan type. One exception is the inulin formed by 

Streptococcus mutans, a major component of dental plaque. The DP of bacterial inulin can 

range to as high as 1,000 residues (French and Waterhouse, 1993) 

8

Table 1 Natural occurance of inulin and oligofructose. 

Sources Inulin 

(%) a 

Oligofructose 

(%) a 

Dry solid 

content b 

Fructan storage 

tissue c 

Wheat (Triticum aestivum) 1-6 1-4 - - - 

Banana (Musa cavendishii 

Lamb) 

Edible 

portion c 

0.3-0.7 0.3-0.7 24-26 NA Fruit 

Murnong 

Alliaceae 

8-13 NA 25-28 NA Root 

Onion (Allium cepa) 2-10 2-6 6-12 Bulb Bulb 

Leek (A. ampeloprasum) 3-16 2-5 15-20* Leaf base leaves 

Garlic (A. sativum) 

Liliaceae 

9-11 3-6 40-50* Cloves Cloves 

Asparagus shoot 

(Asparagus offivinalis) 

1-4 2-3 NA Root Spears 

Compositeae 

Salsify 

(Scorzonera hispanica) 

Globe artichoke 

(cynara cardunculua L.) 

Jerusalem artichoke 

(Helianthus tuberosus L.) 

Yacon 

(Polymnia sonchifolia) 

Chicory (Cicorium 

intybus) 

4-10 2-5 20-22 NA Root 

2-9

where distribution area extends from the east coast of the United States and Canada to the 

central western state and from Southern Canada to Georgia and Arkansas. The tubers contain 

the inulin instead of the starch and sucrose found in most tubers. Jerusalem artichoke is one 

of the primary sources of inulin. Jerusalem artichoke has one or more stems with numerous 

leaves and normally develops tubers 4 to 6 weeks after planting. The plants have tall, stiff 

stems which in some varieties produce small yellow flowers (Frese, 1993). Modern cultivars 

have aimed to select a less knobby tuber, which is easier to peel. “Fuseau”, a French variety 

is on of the best of the traditional ones. Dwarf Sunray is a free flowering, small variety with 

stems height150-210 cm. The usual one has stem height 250-300 cm and never flowers. 

Golden Nugget has carrot like tubers. Stampede is quite maturing early flowering variety 

with large tubers, available in America. There is also a red skinned variety called Smooth 

Garnet (Phillips and Rix, 1993). 

Kiehn and Chubey (1993) investigated the variability of agronomic 

characteristics of Jerusalem artichoke cultivars in southern Manitoba, Canada. Jerusalem 

artichoke was divided into three maturity groups based on the number of days to full flower 

or absence of flowering within the growing season. These group were 1) early maturity 

which reached full flower within 100 days, 2) medium maturity which reached full flower in 

100 to 135 days and 3) late maturity which reached full flower over 135 days. The early 

maturing group produced the low fresh tuber yields (t ha -1 ) and dry matter yields (t ha -1 ) of 

tubers with a trend to increased to late maturity. The late maturity was significantly lower in 

percent of dry matter than other maturing group. 

Plant development can be divided into two phases (Frese, 1993): 

a) Vegetative stage is a phase during planting to flower induction. In this stages 

a large portion of stored carbohydrate is used for stem and leaf production, with accumulation 

of inulin in the stem. Flowering in Jerusalem artichoke marks the culmination of vegetative 

growth. 

b) Reproductive stage is a phase of rapid accumulation of carbohydrate in 

tubers. Inulin is translocated from the stem to the tubers in this stage. Stolones are formed at 

the stem basis and after flower induction the last stolone internodium generally swells to 

rhizome tuber. 

10

Tuber initiation starts about 6 weeks after emergence. The number of tubers per 

plant increases until flowering. After flower initiation, the stem loses its sink activity and the 

stem inulin is relocated to the tubers (Meijer et al., 1993). Translocation of photosynthetic 

products from aerial plant part into the tubers was apparently during flowering before the end 

of vegetative period. During flowering utilization of fructan increases resulting in decreases 

of fructans content (Zubr and Pedersen, 1993). 

Jerusalem artichoke can be grown in both cool-humid and warm-dry climates. 

Total water consumption is higher than chicory because the tuber do not descend into deeper 

soil. Therefore layer irrigation is necessary. The soil pH should be average between 6 and 8. 

Nitrogen supply and irrigation appear to be the major factors influencing inulin yield and 

fructose/glucose ratio. High nitrogen and water supply promote growth of stem and leaves at 

the expense of tuber growth (Frese, 1993). The percent of inulin yield based on total biomass 

ranges between 16 and 39%. Low rainfall and very high temperatures reduce dry matter 

yields (Kiehn and Chubey, 1993). The sum of low solar hours had an irreversibly inhibitory 

effect on the development of plants especially, flowering and flower bud (Zubr and Pedersen, 

1993) 

The distribution of dry matter between tubers and tops was most favorable in 

early cultivar. The composition of carbohydrate in tuber was significantly different in early 

and late cultivars. In early cultivar, the dry matter accumulation in tuber was higher than late 

cultivar. Early cultivar, tuber had lower amount of inulin content (DP>4) and more 

monosaccharide content than late cultivar. In late cultivar, translocation of inulin from tops 

onto tuber was slow causing lower yield in tuber than early cultivar (Zubr and Pedersen, 

1993). Fontana et al, (1993) extracted Jerusalem artichoke juice from different the date of 

harvest. The extracts yield of early tuber was less than late tuber and low total sugar content. 

However, the inulin yield by alcohol precipitation of early tuber was higher than late tuber. 

Also, the early tuber extract contained more high DP (DP>10) than the late tuber extracts. 

De Leenheer and Hoebregs (1994) indicated the structure of native inulin was 

independent of its origins. Inulin was a polydisperse, slightly β (26) branched beta β (21) 

fructan molecule. An average DP, however, is dependent on the plant source, and its time of 

harvesting. 

11

Jerusalem artichoke is one of the sources for industrial inulin production. Inulin in Jerusalem 

artichoke has different DP content (Table 2). However, the DP decreased as the harvesting 

time is postponed (Van Loo et al., 1995). 

. 

Table 2 Describing the inulin in Jerusalem artichoke. 

Composition 

Item Range 

Dry matter content (%) 19-23 

% Fructan of fresh tuber 19-23 

% inulin on fructan 100 

DP 2-19 

DP distribution 

DP 19-40 DP>40 

74% 20% 6% 

DP20 

52% 22% 26% 

Source: Van Loo et al., (1995) 

3.2 Utilization of Jerusalem artichoke 

Jerusalem artichoke tubers are excellent source of both soluble and insoluble 

fiber. The insoluble fiber component with proper bleaching and reduction in off-flavors has a 

potential for usage in white bread. Jerusalem artichoke flour has been added to wheat flour, 

to lattere becomes a low caloric flour and also used in the production of several pasta product 

(Van Loo et al., 1995). The major problem of utilizing Jerusalem tuber flour in food products 

is the undesirable flavor. Jerusalem artichoke can be used in animal feed as flour, dried mash 

and co-extrudated as a source of bifidogenic factors. Incorporating Jerusalem artichoke 

tuber, probiotic bacteria and gamma globulin in milk replacers for neonatal pigs, appears to 

have as potential in reducing the cost of rearing specific-pathogen-free (SPF) pigs. In 

addition, Jerusalem artichoke can improve feed efficiency by reducing diarrhea and feces 

odor in swine and poultry. Baker et al., (1993) evaluated cost of ethanol production from 

Jerusalem artichoke in Canada. The results indicate that Jerusalem artichoke could be grown 

economically as the feedstock for ethanol production as an octane enhancer for transportation 

fuels. 

12

Vogel (1993) reported the production of inulo-oligosaccharides or fructoologosaccharides 

in commercial scale has two processes. In the first process, fructooligosaccharides 

are synthesized from sucrose by fructosyltransferase enzyme. This product 

was developed by Japanese company and had the trade name as neosugar. The other process 

starts with inulins which are partial hydrolyzed by endo-inulinase enzyme, resulting heterooligomers 

or neosugar and homo-oligomers which lacking the terminal glucose moiety. 

Endo-inulinase and exo-inulinase hydrolyses inulin by sequential removal of the terminal 

fructose residues. Endo-inulinase has optimum temperature at 60 o C, and optimum pH is 5.3- 

5.4. At pH value > 5.4 the activity of the enzyme decreases. The fructo-oligosaccharides are 

used in both food and pharmaceutical industry. 

4. Sunflower Head 

Sunflower (Helianthus annuas L.) is in the same family with Jerusalem artichoke. 

Sunflower is valuable crop from an economic viewpoint. The leaves form a cattle food and 

the stems contain a fiber which may be used in paper making. The seed is rich in oil. Deseeded 

sunflower heads are an excellent natural source of low methoxyl pectin. Mature 

sunflower heads contain 150-250 g of pectin per kg head, of which about 25% is water 

soluble (Shi et al., 1996). Most pigments in heads are water soluble and are strongly 

associated with the pectin extract. Pretreatment with a hot water-washing process was used 

prior to pectin extraction to improve pectin quality by removing pigments. Although the 

washing treatment in hot water removes more pigments, it results in an undesirable loss of 

water-soluble pectin (Shi et al., 1996). Sunflower heads are the waste from sunflower seed 

production in Thailand. Therefore, it may be a potential source of inulin. 

5. Harvest Time and Storage Condition on Quality of Jerusalem artichoke 

Jerusalem artichoke tubers are difficult to store outside the soil because of the rapid 

onset of rotting. Therefore, the crop must be harvested according to the daily capacity of 

processing industry (Frese,1993). 

Kang et al., (1993) studied on changing in composition of soluble neutral 

carbohydrates from different harvest date and storage temperature of Jerusalem artichoke 

tubers. The harvest date were (Aug.-Nov. 1992 and Mar. 1993) and the storage temperature 

13

were 4 or 25-40 o C. Breakdown of inulin (GF8) into sucrose and fructo-oligosaccharides 

(GF2-GF7) was highest in November which just after cold-shock. Contents of sucrose and 

fructo-oligosaccharides in tubers harvested in March were much higher than that of tubers 

harvested in September of the previous year. Inulin (>GF8) proportion decreased from 66.4 to 

33.1% while the proportion of fructo-oligosaccharides (GF2-GF7) and sucrose increased from 

25 to 61% and from 3.4 to 13.6%, respectively, at the later harvesting dates. Storage of tubers 

at a low temperature (4 o C) for 34 days also increased their content. However, the amount of 

fructo-oligosaccharides decreased when tubers harvested in March were stored at high 

temperature (25-40 o C). For maximum yield of fructo-oligosaccharides in Jerusalem 

artichoke, it is recommended that tubers should be harvested in March and/or stored at low 

temperature. 

Modler et al, (1993) studied the effect storage temperature on the fructooligosaccharides 

profile of Jerusalem artichoke tubers. Tubers from 4 Jerusalem artichoke 

cultivars (Columbia, Challenger, Sunroot and Fusil) were harvested, trimmed, washed, and 

placed in polyethylene bags. Of the 5 storage treatments tested (5, 2, -10 o C, program cooled 

to -10 o C and ambient), the 2 o C treatment yielded the best quality tuber at the end of 12 

months of storage. Tubers kept at 5 o C showed signs of sprouting after 6 months and some 

spoilage after 12 months. The other treatments were unsatisfactory. During short-term 

storage (18 weeks) the inulin content of the Jerusalem artichoke tubers shifted to the shorter 

chain fructo-oligosaccharides. Fructo-oligosaccharides profile of Jerusalem artichoke tubers 

stored at 2 o C were similar to fresh tubers and had amounts of high degree of polymerization 

(DP) more than the one kept at 5 o C. The rate of respiration of the tubers at 2 o C were slows. 

Tubers stored for 16 months at 5 o C had virtually no fructo-oligosaccharide with a DP >10, but 

had accumulated substantial amounts with a DP 1-4. The result indicated that at 5 o C there is 

sufficient metabolic activity to utilize fructose formed from the breakdown of long chain 

fructo-oligosaccharides. 

Pinpong (1997) found the optimum harvesting stage of Jerusalem artichoke tuber 

ranges between 18-20 weeks after planting based on quantity and quality of tubers. During 

this period, leaves and stem were dry 50-100 % from the top. Weight of fresh tubers 

increased rapidly during 12-18 weeks with flower left 50 %. Highest firmness was found in 

tuber at 20 weeks. At 16 weeks, the tubers were highest in size portion. After 20 weeks 

weight loss, firmness loss, and reduction in specific gravity occurred rapidly. Quantity of 

total nonstructural carbohydrate (TNC) increased between 12-20 weeks (highest for 20 weeks 

14

at 68.00 %) and reduced rapidly after 20 weeks. Cleaning Jerusalem artichoke tubers with 

brush resulting in scratches on the skin which caused loss of storage quality and rot easily 

(Pinpong, 1997). Therefore, scratches must be avoided during cleaning process. Tubers 

stored at room temperature deteriorated quickly. The tubers in open basket became shrivel 

within 5 days. Perforated bag (P.E. size 9 x 14 inch, 0.04 mm. thickness and 4 hole which ¼ 

inch dia.) tubers had storage life 15 days. Tubers in sealed polyethylene bags (0.04 mm. 

thickness) lasted for 7 days before sprouting, moldy and rotting. At low temperature (1, 5 and 

10 o C) storage in sealed bag, tubers could be stored longer than 3 months. 5 and 1 o C storage 

tubers showed comparable quality which was better than at 10 o C. However, total 

nonstructural carbohydrates (TNC) (Nelson’s reducing sugar procedure) decreased for long 

term storage, especially at room temperature storage. Pinpong (1997) suggested that 

Jerusalem artichoke tuber storage for inulin processing should be monitored by to TNC 

content. At high temperature hydrolase enzyme hydrolysed inulin into free fructose. So, low 

temperature and modified atmospheres were suitable for storage of Jerusalem artichoke tubers 

(Kosaric et al., 1984). 

Schorr-Galindo and Guiraud (1997) studied the effect of cultivars and harvest time 

on the inulin composition of Jerusalem artichoke. Six cutivars, Violet de Rennes, K8, 

Nahodka, C76, Kharkov and Huertos de Moya were planted in April or March, and tuber 

samples were taken for analysis at 15 or 30 day intervals between September and the 

following February. Samples were analysed for biomass, total sugars, reducing sugars and 

quantity and sugar composition of the inulin. Generally, tubers grew maximally until late 

autumn, and then slowly, or not at all, over the winter period. Tuber dry weight 

(approximately 20% of fresh weight.) remained unchanged during the winter. In terms of 

biomass gain, the more productive cultivars were K8, C76, Nahodka and Kharkov. 

Variations in sugar yield were similar to those of dry weight. Sugar contents of tubers 

averaged 85% of dry weight. In general, the fructose:glucose ratio (which provides an 

indication of inulin polymerization) reduced from a maximum of 11 at the beginning of 

harvest in September to a minimum of 3 as early as December. Variation in inulin degree of 

polymerization depended on the cultivar and on the harvest date. At the beginning of the 

harvest, tubers contained a greater amount of polymerized sugars which offered industrial 

applications for high-fructose syrup production. 

15

Maximum accumulation of polymerized carbohydrates was reached at the end of 

growth and at the beginning of flowering. After this period polyfructosan content decreased 

whereas the simple sugar concentration increased (Chekroun et al., 1994). 

6. Extraction and Processing of Inulin from Inulin Containing Plant 

Inulin containing plants can be consumed as vegetable for human consumption and 

animal feed. Inulin production from plant material had many steps. The processes consist of 

extraction, clarification/purification, and isolation process. 

Extraction process is a juice extract step from plant material by pressing. This could 

be done by hot water. The colloidal matter, coloring matter, ionic impurity and free amino 

acid extracted in juice were removed by clarification/purification process. The clarifying 

method consists of liming and carbonation, centrifugation, filtration with aid of diatomaceous 

or siliceous earth, and/or activated carbon and adsorbent resin. Isolation of inulin can be done 

by different methods such as precipitation, crystallization, ultrafiltration. 

Vogel (1993) extracted inulin from chicory roots or Jerusalem artichoke tubers by 

cleaned, chopped, mecerated and quickly heated to 93-95 o C for 15 minutes to inactivate the 

enzymes. It was then cooled down to 56-58 o C and filtrated. High amounts of mono-, di- and 

oligosaccharrides could be separated by ethanol precipitation. The precipitate contained only 

components with DP>10. Process for large scale production of inulin, fructose syrup and 

inulo-oligosaccharides from plant material with contained inulin is illustrated in Fig. 3. 

Laurenzo et al. (1999) purified and isolated of inulin from Jerusalem artichoke tubers 

by using ultrafiltration technique. Cleaned Jerusalem artichoke tubers were steamed for about 

10 minutes to inactivate inulin degrading enzyme. The steamed tubers were crushed by meat 

grinder. The crushed tubers were extracted by boiling water (tubers and water as equal mass) 

for 10-15 minutes and filtered with muslin cloth. The extract was sterilized at high 

temperature (143.3 o C) for 5-15 second. 

16

Plant materials 

Washing 

Chopping 

Maceration/Pasteurization 

Cooling 

Enzymatic treatment Enzymatic treatment Pressing 

(Inulinase) (Endo-inulinase) 

Fructose syrup Inulo-oligosaccharides Inulin 

Figure 3 Process flow-sheet for the production of fructose, inulo-oligosaccharides and inulin. 

Source: Vogel (1993) 

Extracted Inulin contained inulin with a range of DP and impurity such as minerals, 

amino acids, protein, fat, cell wall fragment, colloidal matter and particulate matter. 

Extracted Inulin was clarified by filter to remove particulate matter, colloidal matter, and 

microorganism. Hollow fiber membrane (10,000 NMWCO) was used to filter and 

concentrate the extract. This hollow fiber filtration procedure separated the very high (DP> 

40) molecular weight fraction. Different DP fraction could be produced by ultrafiltration. 

The different membrane pore size (2.5K NMWCO and 1K NMWCO) was used to separate 

different molecular weight fraction and reduced the concentration of low molecular weight. 

Inulin fractions having average DP less than a membrane pore size pass through membrane as 

permeate and the fractions having greater average DP were collected as retentate. 

Ionic impurities and color forming impurities was removed by absorbent medium. 

Calcium hydroxide and gaseous carbon dioxide was added to mixture for decolorization and 

deionization. Both lime and carbon dioxide were regulated to control pH between 10.4-10.7. 

The mixture was stood overnight and the pH was reduced to neutral by further addition of 

carbon dioxide. Carbon was added to decolored the mixture. The resulting mixture was 

centrifuged and filtered or ultrafiltrated by hollow fiber membrane to remove the residual 

17

carbon. The clear solution was deionized by passing to the ion exchange resin column in 

order of Dowex monophere 550 A (anion exchange resin; chloride form), mixed bed resin 

(Dowex MR-3) or Dowex Monophere 550A (OH - form) and Dowax Marathon C (cation 

exchange; H + form), respectively. The use of chloride resin in the first step was advantageous 

to effectively remove color and anions which were diffecult to remove with the hydroxide 

resin alone. Position the hydroxide resin before the acid resin also minimized pH excursion 

into the acid region which would damage the polyfructan. Fractionation of inulin to different 

chain length was done by size exclusion chromatography with a series of membranes. A 

typical sequence of membranes might be in ascending or descending order of NMWCO. The 

clarified extract was concentrated by rotary evaporation. The concentrated solution was 

spray-dried using inlet temperature of 195 o C and outlet temperature of 120 o C at a feed rate of 

2.5 kg/hour. Dried inulin was recovered as a fine granular which was moderately 

hydroscopic. 

Juice extraction from Jerusalem artichoke could be carried out by pressing or by 

diffusion (Barta, 1993). At 90 o C soluble substances was 30% higher than at 75 o C. Colloids 

and floating contaminants in the raw juice could be coagulated at pH 10 to 11.5 by means of 

heat and calcium hydroxide. The optimal temperature for clarification was between 85-95 o C. 

Calcium hydroxide was used at 0.2% for extracted juice and at 0.4% for press juice with 

calcium oxide equivalent of the juice (w/v). Calcium, alkali ion and coloring agents could be 

removed from the juice by cation exchange resin. This should be done at low temperature to 

prevent inulin brakedown. The liquid was then neutralized as soon as possible by passing it 

on anion exchang column. It was also recommended to pass it through a decolorizer column. 

The effect of the above-mentioned processes on inulin breakdown was found to be small. 

The reducing sugar only 1.5% increased as compared to total sugar content (Vokov et 

al.,1993). 

Yamazaki et al (1989) prepared from Jerusalem artichoke flour by maceration to a 

pumpable homogenate, preferably in an environment of steam, heating at 150 o C for 15 sec-10 

min and spray-drying. The recovering flour comprised a mixture of 50-60% small 

fructooligosaccharides and 40-50% large oligosaccharides. Extraction and purification of 

fructooligosaccharides from Jerusalem artichoke was difficult because of several limitations 

such as, 1) difficulty in removing the undesirable flavor components, 2) undesirable color 

development during processing due to the action of polyphenol oxidase (Modler et al., 1993). 

The color of Jerusalem artichoke flour produced by spray drying was substantially improved 

18

y heating the whole tubers prior to maceration. This serves to inactivate polyphenol oxidase, 

responsible for the undesirable brown color development. 

Grotelueschen and Smith (1968) extracted fructans from timothy and bromrgrass with 

graded ethanol concentrations at room temperature. They found a percentage of 

carbohydarates extracted from timothy was highest at water extraction. But in case of 

bromograss was highest at 65% ethanol and remained constant. The maximum DP of fructan 

in timothy (~260) was higher than in bromograss (~26). High ethanol concentration extracted 

reducing sugars and sucrose. Therefore, high DP of fructosans was extracted as the ethanol 

concentration was decreased. Ohyama et al, (1990) extracted inulin from yacon (Polymnia 

sonchifolia Poepp. et Endll or P. edulis Wedd) with hot 80% ethanol. It was shown that about 

90% of dry matter of yacon, consisted of substances extractable in 80% ethanol. Inulin was 

detected in the fraction insoluble in 80% ethanol but the content was significantly low and 

also average DP was low. Therefore, yacon belong to the plant group which accumulates 

low-DP fructans like onion. This is different from inulin accumulating plant like Jerusalem 

artichoke. 

In 1991, Wei et al.extracted tubers of Jerusalem artichoke and yacon with 80% 

ethanol. The DP of the oligosaccharides fraction was determined by gel permeation 

chromatography. A series of fructo-oligosaccharides plus glucose and fructose were detected 

in yacon but not in Jerusalem artichoke. In Jerusalem artichoke, oligosaccharides with low 

DP increased while higher oligosaccharides decreased with storage time. Glucose and 

fructose were not found in artichoke after storage. 

Berghofer and coworker (1993a) compared the inulin extraction techniques from 

chicory roots in pilot scale. Extraction of inulin from the roots was carried out using a pilot 

countercurrent screw conveyor slope extractor at 75-80. o C for 54 minutes. Solid particles and 

coloring matter was separated by active carbon and siliceous earth. 

7. Inulin Precipitation 

The standard procedure for precipitating gum/hydrocolloid is by slowly added the 

ethanol (or acetone) to a rapid stirred solution. Polysaccharides do not precipitate well from 

dilute solutions, so concentration is necessary. Generally, three volume of 95 % ethanol are 

added (final concentration = 71% ethanol v/v) which is sufficient to separate high molecular 

19

weight polysaccharides. However, gums are available in wide range of molecular weight. 

These may not precipitate well even by addition of four volumes of ethanol (final 

concentration = 76% ethanol v/v) (BeMiller, 1996). 

Two methods of recrystallization of inulin were water and 50% ethanol precipitation 

(Phelp, 1965). Water precipitation depended on the fact that many fructosans could be 

obtained in microscopically “crystalline” by cooling a solution to –15 o C and allowing it to 

warm up to room temperature. The second method depended on the ability of ethanol to 

precipitate inulin from aqueous solution. The water-recrystallized inulin had less 

contaminants, low fructose and, ash than ethanol precipitation which had high content of DP 

2-8. Inulin from ethanol recrystallization was more soluble than water-recrystallized inulin at 

the same temperature. It might due to the water-recrystallized materials representing one 

form whereas the ethanol-recrystallized might be an unstable second modification form 

(Phelps, 1965). 

Berghofer et al. (1993a) isolated inulin by crystallization and ultrafiltration process. 

For the crystallization process, the extract was evaporated under vacuum to about 40% (w/w). 

Concentrated juice was heated up to 95 o C and slow cooling down to 4 o C with out stirring over 

a period of 30 h. Inulin was precipitated in a crystalline form and was separated and dried. 

The isolation of inulin by crystallization appeared to be difficult and yield were not 

satisfactory. The residual syrup was found to be rich in low molecular weight carbohydrates. 

For the other process, the extract was purified by ultrafiltration membrane. High 

molecular weight inulin was in retentate while the greater part of ash and the nitrogenous 

substance passed into the permeate. The retentate consisted of pure inulin (degree of purity 

98.6%). This retentate proved to be immediatedly ready for spray-dry. The DP of crystalline 

inulin from crystallization process was about 20-25. By contrast, the ultrafiltration obtained 

higher molecular weight inulin. The average DP in the sample was found to be as high as 

40-45. 

Bubnik et al.(1997) also removed dispersed insolubles chicory extract by crossflow 

filtration through Membralox ceramic membranes having filtration area of 2 m 2 and 

diameter 50 and 100 mm. Unrefined extract was vacuum at 55-60 o C to 43.4% dry matter, 

nucleation occurred and followed by cooling for 2 days. The product was a suspension with 

20

inulin purity of 70%. Laurenzo et al. (1999) clarified a crude inulin extract by ultrafiltration 

with hollow fiber membrane with different DP by ultrafiltration with spiral wound membrane. 

8. Analytical Method for Inulin 

The molecular weights of fructans range from 504 to millions. Some of large 

polymers hardly dissolve in hot water, but oligomers are freely soluble in water or ethanol. 

Some HPLC methods now separate the whole range of isomers present in an extract up to DP 

6, and different isomers are distinguishable up to DP 10. Two kinds of columns for HPLC 

that increasingly used are reverse phase and anion exchange at high pH. 

High pH anion exchange chromatography analysis is another technique which can be 

used to differentiate between GFn and Fn compound. The method also provides a 

“fingerprint” of the molecular weight distribution of inulin. The pKa of the alcohol groups of 

carbohydrate range from 12 to 13. They can be separated at high pH by high performance 

anion-exchange chromatography (HPAEC). The high pH (13-14) of sodium hydroxide 

(NaOH) eluent converts hydroxyl groups on the oligosaccharrides into oxyanions (Fig 4). 

The degree of oxyanion interaction with the anion exchange resin (Fig.5) determines 

carbohydrate retention time (Henshall, 1999). Adding a competitive ion such as sodium 

acetate (15-500 mM NaOAc) to the eluent reduces retention time Fig. 6 (Ernst et al., 1996). 

This method, associated with pulsed amperometric detection (PAD), gives high sensitivity 

detection of which is optimized in alkaline solutions. The PAD system oxidizes and detects 

separated carbohydrates as they pass through the detector. 

Figure 4 Oxyanion of carbohydrate in alkaline condition 

Source: Henshall (1999) 

21

Columns are packed with an alkali resistant, pellicular resin with quatenary 

ammonium anion exchange groups (Fig. 5). Two different columns are available from 

Dionex Corp., the often-used Carbopac PA1 and the new PA 100. Its performance in fructan 

separation is similar to the PA1. A metal-free HPLC system is recommended because strong 

alkali will quickly leach metal ions from a stainless system. Eluted, gradients are best run 

with a progressively increasing NaOAc concentration in the presence of constant 

concentration of NaOH. Acetate was recommended because its affinity for the anion 

exchange resin is similar to that of hydroxide which will maximize resolution of the 

carbohydrates. The concentration of NaOH is the most important factor in determining the 

size range of sugars. Between 75 and 150 mM NaOH, several monosaccharide and structural 

isomers in the low DP range can be resolved. At higher concentrations of NaOH, up to 0.5 

M, a higher range of polysaccharides is better resolved. A commercial solution of low 

carbonate 50% NaOH (w/w) should be used, because NaOH in pellets form is usually heavily 

contaminated by carbonate. 

Figure 5 Structure of pellicular ion exchange packing for high resolution carbohydrate 

separations. 

Source: Henshall (1999) 

22

Figure 6 Ion exchange separations are based on the analyze ions in competition with the 

eluent ion for the same exchange sites. 

Source: Pharmacia Fine Chemical 

Relatively crude samples can be injected without substantial interference from 

contaminants because the PAD is poorly sensitive to amino acids and proteins but they may 

foul the column. The PAD response may decrease over weeks if crude samples are used. 

Also, halides should be avoided because they will etch the gold electrode, reducing its 

sensitivity and increasing background noise. Standards must be used for each carbohydrate 

because the PAD response varies with the type of carbohydrate and run conditions (Bancal et 

al., 1993). 

Sensitivity of PAD was decreased as DP increased. The detector measures the 

electrons released during oxidation of the carbohydrate at glod electrode. As carbohydrate 

becomes larger, then proportionally fewer electrons are released per fructosyl unit, and so the 

PAD out put per µg sugar decreases as the DP is increased. Thus quantitative of inulin 

become increasingly difficult for high DP, and also due to limitation of appropriate standards. 

For inulin oligomers to DP8, peak area increased linearly as the concentration of each fraction 

increased. However, each had a unique slope and required different calibration curves 

(Chatterton et al., 1993; Timmermans et al., 1994). 

The difference in chromatographic behavior between glucose-containing inulooligosaccharides 

and those consisting of fructose only can be applied to differentiate the DP2 

23

component of sucrose and inulobiose. The sucrose is eluted very much earlier than the 

inulobiose. High content of mino-,di- and oligosaccharides in inulin extracted solution can be 

eliminated by a single precipitation in aqueous solution of ethanol. The precipitate obtained 

only components with DP>10 (Vogel, 1993). 

9. Inulin Properties 

9.1 Functional properties of inulin 

Standard chicory inulin has the DP range from 2 to >60, with average of about 

10-12. Long chain inulin with average DP of ~ 25 is available for high performance fat 

replacement and texture improvement (Franck and De Leenheer, 2002). Table 3 demonstrated 

the physicochemical properties of standard and long chain inulin. 

Inulin extracted from chicory is a mixture of oligomers with different DP with a 

modal chain length of approximately 9. Inulin extract from chicory has a following typical 

formulation: monosaccharides 2% disaccharides 5% and inulin (GF3-GF 60) 93%. Dry inulin 

powder is white, amorphous, hygroscopic and has a specific gravity about 1.35 and a 

molecular weight about 1600 (Silva, 1996). De Gennaro et al., (2000) determined molecular 

weight of Raftline ® ST (inulin chicory from Orafti) by cryoscopic measurement was 1251. 

Also, Inulin Fn-type had more reducing power than GFn-type, and provide pure sweetness 

like sucrose. 

Inulin powders were odorless and mostly tasteless, however, impurities caused a 

slightly bitter taste. Color of powder was white or light gray depending on purity. The 

particles were a spheroidal under light microscope, whereas were a disk-like shape with 

diameter 1-5 µm under scanning electron microscope (Berghofer et al., 1993a). Kim and 

Wang (2001) characterized physicochemical properties of inulin where melting point was 

observed using a microscope under a hot stage. Inulin melted at 190 o C showed a shiny circle 

in the center. Phase transition was determined by DSC, the peak temperature (Tp) and 

enthalpy of inulin melting were 184.5 o C and 41.75 J/g respectively with 5.3 % (w/w) H2O. 

The peak temperature was decreased as the amount of water increased which water acted like 

plasticizer. Water binding capacity of inulin was less than waxy corn starch. 

24

Table 3 Physicochemical properties of chicory inulin. 

Properties Standard inulin Long chain inulin 

Chemical structure GFn (2 < n< 60) GFn (10 < n< 60) 

Average DP 12 25 

Dry matter (d.m.) (%) > 95 > 95 

Inulin content (%, d.m.) 92 99.5 

Sugar content (% d.m.) 8 0.5 

pH (10% w/w) 5-7 5-7 

Sulfated ash (%, d.m.) < 0.2 < 0.2 

Heavy metals (ppm, d.m.) < 0.2 < 0.2 

Appearance White powder White powder 

Taste Neutral Neutral 

Sweetness (versus sucrose = 100%) 10 None 

Solubility in water at 25 o C (g L -1 ) 120 10 

Viscosity in water (5%) at 10 o C (m Pa.s) 1.6 2.4 

Heat stability Good Good 

Acid stability Fair Good 

Functionality in foods Fat replacement Fat replacement 

Body and mouthfeel Body and mouthfeel 

Texture improvement Texture improvement 

Foam stabilization Foam stabilization 

Emulsion stabilization Emulsion stabilization 

Synergy with gelling agents Synergy with gelling agents 

F, fructosyl unit; G, glusyl unit 

Source: Franck and De Leenheer (2002) 

Inulin is dispersible in water but may have a tendency to clump due to its very 

hygroscopic characteristics. Dispersibility may be improved either through mixing with sugar 

or starch or through instantizing (Silva, 1996). Inulin solution reduces the freezing point of 

water and increases the boiling point of water. However, there were small effect on freezing 

and boiling point as in Table 4 (Silva, 1996; Orafti, 1998a). Inulin is soluble in water with the 

solubility depends on the water temperature. Inulin was hardly soluble in cold water but can 

be dissolved in water at temperature between 40-60 o C. Solubility of inulin increased when 

temperature was elevated. At high temperature (e.g. at 80 o C) when almost all inulin is 

25

dissolved, the solution has Newtonian liquids behavior. In cold water, Inulin is swell and 

insoluble. The viscosity of inulin solution is rather low, i.e., 1.65 mPa.s at 10 o C for 15% (dry 

matter) solution and 100 mPa.s for 30% (dry matter) solution (De Leenheer, 1996). Inulin 

suspension with a large percentage of undissolved portion exhibits hyteresis property which is 

very similar to the rheograms of rheopex-plastic substances. This hysteresis effect is clearer 

in the higher concentration of inulin. Aqueous suspension at higher concentrations of inulin 

were of a gel-like nature (Berghofer et al., 1993a; Kim and Wang, 2001). 

For improving inulin properties, Berghofer and coworker (1993 b) modified 

inulin by esterification with acetic/adipic anhydride and sodium tri-metaphosphate. Modified 

inulin had higher viscosity than native inulin and decreasing solubility. However, the 

disadvantage of these derivatives was low stability. Phosphate derivative was also able to 

form thermoreversible gels which firmer than those of native and adipate derivatives at the 

same concentration. 

Table 4 Freezing and boiling point of inulin solution. 

Concentration (%) Raftiline ST/GR/ST-gel Raftiline HP/HP-gel 

Freezing point ( o C) 

5 -0.1 -0.04 

10 -0.3 -0.08 

15 -0.5 -0.14 

Boiling point ( o C) 

30 100.5 100.3 

35 100.6 100.4 

Raftiline ST/GR/ST-gel contained 92 % inulin, sugar 8%, and average DP 10 

Raftiline HP/HP-gel contained 100 % inulin, and average DP > 23 

Source: Orafti (1998a) 

9.2 Food application and nutritional aspects of inulin 

Inulin and oligofructose can be used for either its nutritional advantage or its 

technological properties, but it is often used to offer a double benefit. They are used as food 

26

ingredients by food industry for a variety of applications. They can improve organoleptic 

quality and balance nutritional composition. The application of inulin in food and drinks is 

provided in Table 5. 

Inulin and oligoructose are confirmed as food ingredients, not food additives. In 

the U.S.A. they are generally recognized as safe (GRAS). Some EU members (Belgium, 

Germany, Italy) have legal definitions which include inulin and oligosaccharides. In the 

United Kingdom, inulin is ready classified as a non-starch polysaccharides as dietary fiber. 

Inulin has been shown to provide several interesting nutritional properties to 

animal and human in Table 6. Inulin and oligofructose are resistance the hydrolysis by human 

enzymes. Thus they have one of the major properties of dietary fiber. They are soluble and 

highly fermentable but of low viscosity. They can be classified as dietary fiber. Which 

regulated both gastrointestinal and systemic functions (Roberfroid, 1993). Inulin is 

recommended sometimes for diabetics. It has a mildly sweet taste, and is filling like starchy 

foods. But because it is not absorbed, therefore it does not affect blood sugar levels. 

In southern European countries, recommendation inulin for consumption is about 

6 g daily. Fructo-oligisaccharides posses a sweetness about 0.4 to 0.6 times of sugar and can 

be regarded as a kind of soluble dietary fiber with a reduced caloric value. Recent research 

has shown an important physiological action for inulin (Roberfroid, 1993; Gibson et al., 

1995). In large intestine fruto-oligosaccharides are fermented by bacterial, preferentially by 

bifidobacteria to CO2, methane and volatile or short chain fatty acid that exert systemic 

effects on lipid metabolism. The health benefit of colonization of bifidobacteria in large 

intestine is to eliminate other pathogen bacteria as Clostridium and Staphylococcus spp. 

(Vogel, 1993). Like some pectins and fructooligosaccharides, inulin is a preferred food for 

the lactobacilli in the intestine and can improve the balance of friendly bacteria in the bowel. 

Subjects in one trial were given 15 grams of inulin a day for fifteen days where lactobacillus 

bifidobacteria increased by about 10% during that period. Gram-positive bacteria associated 

with disease declined. Bifidobacteria digest inulin to produce short chain fatty-acids, such as 

acetic, propionic, and butyric acids. The first two may be used by the liver for energy 

production, while butyric acid has cancer-preventing properties within the intestine. Recent 

animal research also shows that inulin prevents precancerous changes in the colon (Reddy et 

al., 1997). 

27

Table 5 Food application of inulin. 

Application Functionality Dosage level (% w/w) 

Dairy products 

(yogurts, cheeses, dessert, 

drinks) 

Fat replacement, Body and 

mouthfeel, Foam stability, Fiber 

and prebiotic 

Frozen desserts Fat replacement, Texture 

improvement, Melting behavior, 

Low caloric value 

Table spreads and butter-like 

products 

Fat replacement, Texture and 

spreadability, Emulsion 

stabilization, Replacement of 

gelatin, Fiber and prebictic. 

Baked goods and breads Fiber and prebioctic, Moisture 

retention 

Breakfast cereals and 

extruded snacks 

Fiber and prebiotic, Crispness and 

expansion, Low caloric value 

Fillings Fat replacement, Texture 

improvement 

Salad-dressing and sauces Fat replacement. Mouth feel and 

body, Emulsion stability 

Meat products Fat replacement, Texture and 

stability, Fiber 

Dietetic products and meal 

replacers 

Fat replacement, synergy with 

intense sweeteners, Body and 

mouthfeel, Fiber and low calorie 

Chocolate Sugar replacement, Fiber, Heat 

resistance 

Tablets Sugar replacement, Fiber and 

prebiotic 


2-10 

2-10 

2-10 

2-15 

2-20 

2-30 

2-10 

2-10 

2-15 

5-30 

5-75 

28

Table 6 Biological and nutritional properties of inulin. 

Degree of evidence Evidence 

Strong Non digestibility and low acloric value (1.5 kcal g -1 ) 

Suitable for diabetics 

Soluble dietary fiber 

Stool bulking effect : increase in stoole weight and stool frequency, 

relief of constipation 

Modulation of the gut flora composition, stimulating beneficial 

bacteria ( bifidobacterium) 

and repressing harmful bacterial (Clostridium): prebiotic/bifidogenic 

effect 

Improvement of calcium and magnesium bioavailability 

Promising Reduction of serum triglycerides and insulin levels 

Reduction of colon cancer risk (in animal models) 

Modulation if immune response 

Protection against intestinal disorders and infections 


9.3 Gelling formation and properties of inulin 

Polysaccharides solution have three types of system: macromolecular solution, 

weak gels and strong gels. Three type of systems are easily done by mean of viscoelastic 

measurements. The mobility of macromolecular in solutions mainly due to degree of 

entanglement of chains. The three dimensional net work of gel is structured by junction 

zones arising from specific interactions between polymer chains and absence of mobility of 

the chains (Doublier and Cuvelier, 1996). 

At concentrations of 1-10% inulin increases its viscosity, while at a 

concentration from 11-30% a thickening is noticed but no gelling. A inulin gel is formed 

upon cooling for about 30-60 min. As the level of inulin in water is increases, the formation 

of gel takes less time. The gel formation is almost instantaneous at about 40-45% inulin 

solids in solution. Inulin gel is very creamy and fat like. As the level of inulin gradually 

increases to about 50% the gel becomes very firm but still has a fatty feel to touch, indicating 

29

that the strength of gel depends on the concentration of inulin among other factors (Silva, 

1996). 

Frank and Coussement (1997) mentioned that at high concentration (> 25% in 

water for standard inulin and >15% for long chain inulin). Inulin has gelling properties and 

forms a particle gel network after shearing. The particle gel of inulin imitates fat extremely 

well. It provides a short spreadable texture, a smooth fatty mouth feel, as well as a glossy 

aspect and well-balance flavor release. The gel strength depends on inulin concentration, 

total dry substance content, the shearing parameters such as temperature, time, speed, 

pressure, and also on type of shearing device used, but is not influenced by pH between 4 and 

9. The gel strength also increases during the first 24 h after shearing. Electron microscopy 

has shown that such as inulin gel is composed of a three-dimensional network of insoluble 

submicron inulin particles in water. These particles of about 100 nm in size aggregate to form 

larger clusters having a diameter of 1-5 µm. Large amounts of water are immobilized in that 

network, as determined by NMR experiments, which assures the physical stability of the gel 

in function of the time. 

Inulin gel exhibits a viscoelastic rheological behavior that is characterized by 

certain elasticity as well as a viscosity. The gel also shows shear-thinning and thixotropic 

properties, and is characterized by relatively low yield stress (i.e., 1540 Pa for a gel of 30% 

standard inulin in water at 25 o C). When submitted to an increasing deformation (Oscillatory 

rheological experiments), the gel gradually loses its solid property. The elasticity modulus 

decreases whereas the fluid properties and thus the viscosity modulus, which are initially 

lower, increases. The dynamic behavior of inulin gel is quite similar to that of margarine type 

product, and rather different from that of typical polymer gels such as starch. Furthermore 

inulin displays synergy with most gelling agents, e.g., gelatin, alginate, k-and i- carrageenan, 

gellan gum, maltodextrin. The gel strength obtained by combining them with inulin is higher 

than the sum of the gel strengths obtained for the two gels made separately (Frank and 

Coussement, 1997) 

Kim and Wang (2001) and Kim et al. (2001) studied on kinetic and factors of 

inulin gel formation. At high temperature, solubility of inulin increased significantly and also 

hydrolysis of inulin. The solubility and hydrolysis of inulin were pseudo first-order kinetic. 

Nevertheless, the rate of solubility was higher than that of hydrolysis. Inulin was hydrolyzed 

rapidly at 80 o C and higher. Gel formation of inulin could be induced by shear and heat. For 

30

shear induced gel formation, with high shearing (5000 rpm), lower concentration of inulin 

was required to form gel and with smoother texture than low shearing (250 rpm). In 

addition, gel from high shear had higher gel strength at the same condition. Thermally 

induced gel showed higher gel hardness than shear induced gel at the same concentration. 

These results suggested that shear induced gel formed gel with hydrogen bond and van der 

Waals interaction among particle but thermally induced gel could form the network structure 

among the molecular chain through entanglement of molecules (Kim et al., 2001). 

Kim et al. (2001) also mentioned that the critical concentration to form gel was 

depended upon the preparation temperature. At severe temperature and pH (1-2), inulin was 

hydrolyzed to short chain or low DP which decreased gel formation. Thus, important factor 

of gel formation was concentration of critical chain length of inulin. At low concentration (< 

5%) inulin-water mixture did not form gel because the system did not have enough particle or 

molecular density of inulin chains to reach the critical clouding effect. Inulin could form gel 

when cool down the solution to low temperature. The speed of gel formation was also related 

with the left particle. Incomplete dissolution left some crystalline nuclei in suspension. 

These nuclei facilitated the crystallization process of gel forming. So, firming of the inulin 

gel took longer time when inulin was totally dissolved. Solvent adding such as, ethanol and 

glycerol, which has low polarity than water could accelerate gel setting. Kim and co-worker 

(2001) concluded that the best range for gel formation were 20-30% (w/v) inulin (Raftiline 

HP), 70-90 o C heating for 3-5 min at pH 6-8, and cool down to room temperature (25 o C). 

Nuclear magnetic resonance (NMR) is the powerful technique to quantify the 

immobilized fractions in relation to physicochemical properties of gel. NMR spectroscopy 

was used to study the physiochemical properties of inulin and inulin gel. De Gennaro et al, 

(2000) investigated inulin solution by 1 H-NMR pulse relaxation times (T1 values). T1 values 

decreased with increasing molecular weight and concentrations as a result of increased 

protons order and reduced water mobility. 

Cross-relaxation NMR spectroscopy or magnetization transfer spectroscopy can 

selectively detect solid-like components in aqueous gel, by monitoring the response of the 

H2O NMR signal upon saturation of the immobilized carbohydrate material by low-power 

irradiation. Quantitative information from cross-relaxation was the terms of the molecular 

mobility and amount of the rigidified phase. Two parameters that could be obtained to 

monitor the growth of solid-like component in inulin gel were transverse relaxation parameter 

31

of solid pool (T2b) which was proportional to its molecular mobility and T2a was transverse 

relaxation time of the mobil pool, which decreasing in rigid phase formation. Rab Mb. was a 

measure for the abundance of the solid phase. Rab Mb/T2a was exhibited proportional to 

formation of solidified phase. T2b was indicative for fairly rigid solid lattice at short time 

stage in the aging process. The mobility of the rigid polymer was invariant during the aging 

process. At low concentration, the degree of inulin solidification and gel firming were lower 

than high concentration. Cross-relaxation NMR spectroscopy could be used as rapid sample 

and non-invasive method to probe gel firming because the G’ values from rheological 

measurement and the θ value from NMR experiment were good correlation (Van Duynhoven 

et al., 1999). 

Mixed hydrocolloid gels were of interest because they could synergistic 

interaction which enhanced gelling properties. In Orafti report, combinations of Raftiline HP 

with thickeners such as guar gum, lamda-carrageenan, Na-caseinate, locust bean gum, 

xanthan gum and CMC were not synergism but between Raftiline HP and gelling agents such 

as starch, maltodextrin, gelatin, iota- and kappa-carrageenan, gellan gum, alginate and LM 

pectin were synergism, when measured as the gel strength (Orafti, 1998b) 

Zimeri and Kokini (2002) studied mixed polymers system of inulin and 

amylopectin. Native inulin in semi-crystalline and amylopectin were equilibrated at different 

storage relative humidities. At storage relative humidities below 75% (25 o C), inulin was in 

glassy state when it pre-solubilized dried and stored at low moisture content and crystallinity 

was low (~13%). Crystallinity increased to 42% dramatically at relative humidities 

corresponding to conditions above the glass transition (Aw > 0.75). Gelatinized amylopectin 

remained in an amorphous state at relative humidities below 93% (25 o C). Inulin and 

amylopectin glass transitions temperature were well-fitted by the Gordon-Taylor equation 

(Zimeri and Kokini, 2002). 

Inulin (100%), amioca starch (98% amylopectin) and mixed inulin-amylopectin 

sample (0, 10 and 20% inulin, wet basis) were equilibrated at different water activity (0 to 

0.93). This system was investigated for glass transition temperature by DSC. The Tg of 

mixed system had two peaks, one at high temperature range closed to that of pure 

amylopectin and the other at low temperature range closed to that of pure inulin. The glass 

transition of inulin was about 30% smaller than that of amylopectin. It was shown that there 

were lack of interaction between them. Thus, it was concluded that phase separations had 

32

occurred (Zimeri and Kokini, 2003 a). The knowledge of Tg of inulin-amylopectin systems 

provided information to understand the effect of ingredient interaction on phase transition. 

Therefore, these would apply to the success in design texture and stability of food products. 

10. Hylon ® (High Amylose Starch ) and Amioca TM (High Amylopectin Starch) 

Hylon ® or high amylose maize is high amylose corn starch granules which obtains 

from corn kernels by means of milling and purification process. The granule is partially 

crystalline solid compound of amylose and amylopectin. Differences in the amounts of 

amylose and amylopectin lead to appreciable changes in physical properties and functionality. 

Amylose is mainly linear polymer of anhydroglucose units by 1,4-∝-D glycosidic bonds. 

Amylopectin has molecular weight approximately 1,000 times more than amylose and highly 

branch with 1,6-∝-D glycosidic bonds. 

Plant deposits amylose in an amorphous form, whereas amylopectin is in cystallinity. 

At higher level of amylose, the partially crystalline structure of the starch granule is 

significantly altered. High amylose granule has a lower percentage of crystallity than high 

amylopectin starch. From wide angle x-ray scattering (WAXS) demonstrated crystal pattern 

of high amylose (Hylon) starch is B-type plus V-type, whereas high amylopectin (Amioca TM ) 

is A-type (Richardson et al., 2000; Shi et al., 1998). Starch granule of B-type has higher 

melting temperature as well as being more resistant to enzyme degradation and has a higher 

gelatinization temperature than normal starch. Amioca TM is a corn starch containing no 

amylase. 

The amylose contents of various type of starches, as determined by potentiometric 

iodine method,: 27% for corn starch, 56.8% for hylon V starch, 71% for hylon VII starch and 

89.9% for low-amylopectin starch (LAPS) (Richardson et al., 2000). Jane and coworkers 

(1999) indicated that long branch chain of amylopectin can bind with iodine and develop blue 

color similar to amylase which can cause higher apparent amylase content. Apparent amylose 

content of hylon V and hylon VII was 52.0% and 68.0%, whereas absolute amylase content 

was 27.3% and 40.2%, respectively. 

Under heat and excess water, the semicrystalline starch granule will melt (gelatinize), 

absorb water and swell, producing viscous solution. At higher temperature (90 o C) and longer 

33

heating time, the starch granule will disintegrate, leading to nearly complete solubilization. 

The B-type crystal form of amylopectin in high amylose starches results in higher 

gelatinization temperature than native corn starch. Amylopectin in high amylose starch 

contains a higher portion of longer side chain, while amylopectin in native corn starch has 

higher small side chain (Richardson et al., 2000). The high amount of amylose affects 

solubilization and gelation behavior and acts as restraint to swelling. Because of hydrogen 

bonding between chains, the high temperature (> 90 o C) and pressure such as in jet cooking or 

longer heating time are often required for complete solubilization or gelatinization 

(Richardson et al., 2000). Gelatinization temperature range of hylon V and VII measured by 

DSC was 41.6 and 58.8 o C, respectively. Large enthalpy changes were found indicating large 

amounts of energy were needed to gelatinize crystallites. (Jane et al., 1999). 

The rheological properties of gelatinized high amylose starches are dominated by 

amylose gelation. The very high amylose content affected swell limitation of granule which 

resulting in low viscosity paste (Jane et al., 1999). During gelatinization, only small fraction 

of amylose diffused out of swollen granule. This caused relatively low viscosity when 

compare with other water-soluble polysaccharides. Once the amylose is solubilized, it is 

rapidly forming double helix that aggregate as the solution is cooled. At a concentration > 

1%, three-dimensional gel net work formed. The high amylose starches form firm and turbid 

gels. As the amylase percentage increased the starch gel because tougher and more rubbery 

(Case et al., 1998), and also formed strong and brittle films (Richardson et al., 2000). The 

retrogradation percentage of hylon VII as calculated by ∆H retrogradation starch / ∆H gelatinization was 

61.0. Whereas hylon V was 8.08 which corresponding to higher amylase content in hylon VII 

than in hyon V. This indicated that high amylase was high retrogradation (Jane et al., 1999). 

Pasting properties of starch were affected by amylose and lipid contents, and by 

branch chain-length distribution of amylopectin. Amylopectin contributed to swelling of 

starch granules at pasting, whereas amylose and lipids inhibited the swelling (Tester and 

Marrison, 1990). 

The amylopectin chain-length and amylose molecular size produced synergistic 

effects on the viscosity of starch pastes (Jane and Chen, 1992). High amylose maize V and 

VII starches did not completely gelatinized under the RVA cooking conditions, because there 

had very high gelatinization temperature (Jane et al., 1999). 

34

10.1 Gelation 

Morris (1998) mentioned gelatinization results in a loss of molecular orientation 

and a breakdown of the crystalline structure. Swelling of the granules leads to solubilization 

of amylose. Under shear the granule structure may break down into fragments freeing 

amylopectin. Under non-shearing conditions there is little evidence for the release of 

amylopectin, even upon heating to 100 o C. Thus heating results in porous amylopectin-based 

granules suspended in a hot amylose solution. On cooling the samples form turbid 

viscoelastic pastes. High concentrations (>6% w/w), starch form opaque thermoirreversible 

elastic gels. The reinforcement of amylose gels is promoted by the porous starch granule 

particles. The important factors governing paste and gel rheological properties are rheology 

of the matrix (amylose), rigidity of the filler (granule), volume fraction of the filler, and the 

filler-matrix interaction. An amylose-amylopectin network is the classical fringed micellar 

gel structure. Amylose molecules are considered to participate in several junction zones and 

deformability is attributed to perturbation of the polymeric linkages between junction zones. 

The amylose forms opaque elastic thermoirreversible gels at concentrations >1.5% w/w. 

Solubilization of a sufficient quantity of amylose is an essential requirement for the gelation 

of starch. For amylose, the critical overlap concentration (c*) was very close to the critical 

concentration (co) for gelation. Thus, the gelation process will involve conversion of the 

weak, temporary network into strong permanent network. The gelation can occur by different 

mechanism depends upon preparation conditions. In case of amylose two extreme scenarios 

would be the formation, at high molecular weights, of a fine network which then becomes 

coarsens. Or, at low molecular weights, where the formation of coarse network aggregates 

which then forms linkage to form a network. The amylose gel consists of an amorphous 

network containing crystallites, which provide permanent cross-links. The level of 

crystallization within the gel is depended on the amylose concentration, but the rate of 

crystallization is independent of polymer concentration. Small angle neutron scattering 

(SANS) supported the concept of phase separation follwed by network formation and 

crystallization. On the basis of electron microscopy combined with other technique suggested 

that the crystalline regions within the networks are oriented perpendicular to the fiber axes of 

the gel network. 

The branched amylopectin can also gel. On cooling the solutions, amylopectin 

eventually associates over a long period of time to form opaque thermoreversible gels. Crosslinking 

appears to be related to crystallization, and both processes are thermoreversible. It is 

35

suggested that the association may involve co-crystallization of short branches of the 

amylopectin molecules. Gelatinization of starch in the presence of shear results in a mixture 

of amylose and amylopectin. There was evidence that amylopectin inhibits amylose 

aggregation. Starch gels are composites consisting of swollen granules embedded within 

interpenetrating amylose gel. The granules increase the stiffness of the amylose matrix 

(Morris, 1998). 

10.2 Viscoelastic property of amylose and amylopectin gel 

Table 7 demonstrated variation in the linear viscoelastic and rheological 

properties range of starch: amylose and amylopectin. The critical concentration (Co) of 

amylase, below which cannot form gel, is about 0.8-1.1%. It appears to be independent of 

molecular weight and the origin of biolpolymer. During sol-gel transition, amylose 

undergoes conformational ordering resulting in aggregation and association of polymer chains 

to form a three-dimensional network. Amylose gel formation progress through two stages, 1) 

molecular aggregation by double helix formation and elongation and 2) lateral association of 

the helical regions. These stages are influenced by molecular weight or the degree of 

polymerization. Aggregation is favored by high DP, where as lateral association is favored 

by low-molecular weight amylose molecule (Okechukwu and Rao, 1998). 

Amylose gels are generally stiff. G′ is highly dependent on amylose 

concentration. G′ value does not vary with frequency during rheometer measurement. The 

gels are irreversible to temperature below 100 o C and develop full gel strength within 2-4 hrs. 

Amylopectin require high concentration (10% and above) and low temperatures for gelation. 

Gel strength approaches the limiting value. G′ increases faster than G′′ and shows a linear 

dependence on concentration. G′ value decreases with frequency. Amylopectin gels are 

thermoreversible at temperature below 100 o C (Okechukwu and Rao, 1998). 

Amioca (8%w/w) gel measured in steady shear displayed an upswing in apparent 

viscosity at low shear rates which indicated apparent yield stress. Dynamic rheological data 

performed at 4% strain showed higher G′ than G″. The slopes of moduli were parallel which 

each other. At 4% strain it was found to be in the linear viscoelastic region at 20 o C. Amioca 

gel behaved like a weak gel (Chamberlain and Rao, 1999). 

36

Table 7 Rheological properties of amylose and amylopectin. 

Index Amylose Amylopectin 

Minimum conc. for gelation(Co) ~ 0.9% (w/w) and 

~ 10% (w/w) but 

(c*~0.5%) 

Linear viscoelastic range 1-10 % strain 0.1 % strain 

Concentration dependence of G′ G′ ∝ c ∝ (power relation) G′ ∝ c ∝ (linear relation) 

∝ ~ 3-7 

Gel strength development Fast and exponential 

maximum gel strength 

developed in less than 24 h 

Reversibility Irreversible at temperatures 

< 100 o C but reversible at 

temp>~ 140 o C 

Temperature dependence of G′ Weak Strong 

c* = coil overlap concentration 

Source: Okechukwu and Rao (1998) 

37 

Slow initially and sigmoidal 

with respect to time; max. 

strength attined in 30-40 

days 

Reversible at temperatures 

< 100 o C 

Aqueous amylopectin solutions of sufficient high concentration could form 

cross-linked thermoreversible gels upon cooling to below room temperature (Durrani and 

Donald, 1995). Amylopectin gelation was accompanied by development of crystallinity. 

DSC gel melting endotherm provided a measurement of the degree and perfection of the 

crystallinity in the gel. For gel stored at 4 o C, the crystallinity covered a wide range of 

perfection. The wide angel x-ray scattering (WAXS) pattern of amylopectin gel had 

diffraction peaks at the same positions as those of starch with a B-type pattern, although the 

crystallnity of waxy maize starch had a A-type. The gels were white and opaque, indicating 

that they consisted of phase separated regions. 

Oscillatory testing on gel of low amylopectin starch (4.8% solid), hylon V (4.7% 

solid) and hylon VII (4% solid) by Case et al. (1998) found that the onset of gelation occurred 

first in LAPS followed by hylon VII and V, respectively. Temperature for gel setting related 

with amylose content where low amylopectin starch could set at 45 o C while hylon V could set

at lower temperature (20 o C). Gel of these starch demonstrated strong gel, which high 

amylose content show higher G′ value. 

11. Mixed Polysaccharide Gels 

Gels form continuous phase in a number of manufactured foods. They generally form 

by aggregation of molecules into three-dimensional network. In some cases the aggregation 

may be into a fibrous network such as pectin and in other cases the network may be produced 

from clumps joined together, such as yogurt. Fibrous gels are more usually encountered 

when gel are set on cooling, presumably as this allowed time for the molecules to aggregate in 

an ordered form. Some gels develop as a mixture of continuous and dispersed phases. 

Examples of this type of gel are starch gels, where the starch granules remain embedded in an 

amylose matrix (Lewis, 1988). 

Gelling agent are often used as mixture. In some cases discrete phases are formed 

while in other cases a combined gel network are formed. Varying the proportions of gelling 

agent makes it possible to reverse the phases and to change the distribution of the dispersed 

phase, and consequently to modify the texture of the overall system (Lewis, 1988). Mixed 

polymer gels are of interest because they provide realistic models for complex food structures 

or natural tissues. They also provide relatively inexpensive methods for manipulating 

rheology and texture. 

11.1 Single component gels 

Single component polymeric networks are the simplest molecular models for 

biopolymer gels. The advantage of studying single component gels is that they provide ideal 

model for investigating mechanism of gelation and also for devising mathematical 

descriptions of rheological and mechanical behavior. Physical and physicochemical studies 

have established the basic principles of most gelation processes and thus revealed the main 

factors which control gelation. The effect of external variables such as pH, ionic strength, 

temperature and the nature of added co-solutes can be explained in terms of molecular models 

for gelation (Brownsey and Morris, 1988). 

38

11.2 Two component mixed gels 

It is possible to divide binary mixtures in a few simple type of gel. Four types of 

gel structure can be described in Fig. 7 (Morris, 1998). 

a) Swollen networks are formed when one component forms a network and the 

other component resides within and swells the network. Let the polymer which forms the 

network be designated A and the soluble entrapped polymer designated B. The presence of 

polymer B may influence gelation of polymer A, and affect conformational transition of 

polymer A and/or swell the polymeric network (Fig. 7A). 

b) Interpenetrating networks consist of two independent networks each 

spanning the entire sample volume and interpenetrating through each other (Fig.7B). One of 

the most common types of interpenetrating network is where a preformed network is swollen 

and a second system is crosslinked in situ. If there is a high degree of miscibility, then an 

interpenetrating network will result. If not, phase separation is observed with an 

interpenetrating network structure only at the boundaries. True interpenetrating networks are 

rare, due to phase separation or the possibility of interactions, which may give rise to coupled 

networks. Nevertheless, it is necessary that a means of identifying a structure as an 

interpenetrating network be available, the most usual entails monitoring the glass transition 

temperature (Tg). However, the existence of a single Tg is not itself a sufficient criterion that 

two materials are miscible. It may be that even on a microscopic scale the structure is 

heterogeneous (Brownsey and Morris, 1988). 

c) Phase separated networks result on mixing incompatible polysacchrides. 

Gelation within one or both of the two phases arrest phase separation forming a composite of 

filled gel (Fig.7C). The most common example of phase separated network is starch. Starch 

gel can be modelled as an amylose network, interpenetrating and reinforced by swollen 

granules, composed mainly of amylopectin. Several experimental techniques can be used to 

establish phase separation of which microscopy is probably the most valuable. A difficulty 

with mixed polysaccharides model study is to achieve differential contrast for the two 

components. Staining techniques may be useful. At molecular resolution using electron or 

atomic force microscopy it may be possible to distinguish different molecular species on the 

basis of size and shape. A further problem, as identified through microscopic studies of 

39

mixed gels, is that each phase may not be pure but will contain multiple inclusions of the 

other phase. 

d) Couple gel networks are attractive commercially because they offer the 

prospect of developing new mechanical or textural properties. The junction zones in coupled 

gels are new ordered structures (Fig.7D). Physical and chemical techniques may be employed 

to test the hypothesis of intermolecular association. The most powerful direct physical 

technique is X-ray diffraction of oriented fibers prepared from the gels (Brownsey and 

Morris, 1988). Considerable research has gone into the study of synergism in binary mixed 

polysaccharides. Synergism implies that gelation is enhanced on mixing the two 

polysaccharides. Example, pectin-alginate mixtures will gel under conditions for which the 

individual components will not gel. 

Figure 7 Schematic models for two-component mixed gel networks. a) swollen network, 

b) interpenetrating network, c) phase separated network and d) coupled network. 

Source: Morris (1998) 

12. Viscoelastic Measurement for Rheological Property 

This method can monitor the phase transition of solid and liquid when applied the 

stress and strain to the sample. It also can monitor gel formation and aging process of gel. 

Rheology is the science of the deformation and flow of matter. There is three ways to 

deform a substance: shear, extents, and bulk compression. Common instruments for 

measuring rheology properties of fluid and semi-solid food are rotational type and tube type 

40

instrument. Rotational instruments may be operated in the steady shear (constant angular 

viscosity) or oscillatory (dynamic) mode. Under Steady shear conditions viscoelastic fluids 

exhibit normal stresses which provide elastic characterization. Unsteady state shear 

measurements provide a dynamic means of evaluating viscoelasticity . The two major 

categories of unsteady shear testing are transient and oscillatory. Oscillatory (dynamic) shear 

tests provide the complex viscosity (η*), storage modulus (G′) and loss mogulus (G″) with 

different frequency at the constant temperature (Ivanov et al., 2001). The parameters in the 

viscoelastic measurements are: 

Strain (γ) is deformation of material 

Stress (σ) defines as a force per unit area and usually express in Pascal (N/m 2 ), may 

be measured as tensile, compressive, or shear. 

Modulus is defined as the ratio of stress to strain while a compliance is defined as the 

ratio of strain to stress (Steffe, 1996a) 

For oscillatory testing, a sample is subjected to harmonically variation (usually 

sinusoidal) stress or strain with small amplitude deformations in a simple shear field. Many 

parameters can be generated from oscillatory experiments (Table 8). Oscillatory testing is 

useful in many application including gel strength evaluation, monitoring starch gelatinization, 

studying the glass transition phenomenon, observing protein coagulation or denaturation, 

evaluating curd formation in dairy products, shelf life testing, and correlation of rheology 

properties to human sensory perception. Typical commercial instruments operate in the shear 

deformation mode. Shear strain may be generated using parallel plate, cone and plate, or 

concentric cylinder fixtures. Dynamic testing instruments divide in two categories: controlled 

rate instruments where the deformation (strain) is fixed and stress is measured, and controlled 

stress instruments where the stress amplitude is fixed and the deformation is measured. Both 

produce similar results (Steffe, 1996b). The lower plate is fixed and the upper plate is 

allowed to move back and forth in horizontal direction. 

Oscillatory or dynamic testing uses controlled stress/strain rheometer to determined 

viscoelastic properties of fluid. Evaluation of G′ and G″ as a function of frequency, time and 

temperature provides useful information on the phenomenon of gelation and the melting 

characteristics of thermoreversible gels (Okechukwu and Rao, 1998). 

41

Table 8 Parameters that can be measured by oscillatory shear testing. 

Viscosity Complex, Pa s η* 

Dynamic, Pa s η′ 

Modulus Complex shear, Pa G* 

Shear storage, Pa G′ 

Shear loss, Pa G″ 

Compliance Complex shear, J* 

Shear storage, J′ 

Shear loss, J″ 

Other Out of phase component of the complex 

Source: Adapted from Steffe (1996b) 

viscosity, Pa s η″ 

The rheological properties are resolved into elastic and viscous component. The 

storage modulus G′ express the magnitude of stress in term of an elastic that stored in 

material. Loss modulus G″ or viscous is a measure of the energy lost as viscous of 

deformation. The tangent of phase shift or phase angel called tan delta, (tan δ) = G″ / G′, is 

the ratio of the energy lost to the stored of deformation and also a function of frequency. The 

tan δ can vary from zero to infinity. The tan δ is very high for dilute solutions, 0.2 to 0.3 for 

amorphous polymers, and low (near 0.01) for glassy crystalline polymers and gels (Steffe, 

1996 b). These parameters often measure as function of time at constant frequency or as a 

function of frequency at a constant temperature. G′ and G″ are influence by frequency, 

concentration, temperature, and strain. For strain value within the linear region, G′and G″ are 

dependent of strain (Okechukwu and Rao, 1998). If material is Hookean solid, the stress and 

strain are in phase and phase lag (δ) =0. Hence, G″ and η′ are also equal to 0 because there is 

no viscous. If material behaves as a Newtonian fluid, the stress and strain are 90 degree out 

of phase (δ=π/2). In this case G′ and η″ are zero because the material does not store energy 

(Steffe, 1996b). 

Phase lag (δ) is meaningful to examine behavior of fluid or solid-like, and relative to 

the strain. Phase lag may be calculated from the loss and storage moduli: δ = arctan (G’/G’’). 

High value of δ at low frequencies indicates a tendency toward more fluid-like behavior for 

42

oth the dilute and concentrated solutions at low deformation rates. More solid-like behavior 

is observed for these solutions at the high deformation rates associated with high frequency. 

The phase lag for the gel is indicating consistent solid-like behavior over the entire frequency 

range (Fig. 8). 

The data from measurement can classify material to four classifications, i.e., dilute 

solution or Newtonion, concentrate solution or entanglement network system, weak gel, and 

strong gel. Weak gel have G′ higher than G″ which both the moduli almost paralle to each 

other, whereas strong gel also have G″ larger than G′, however G′ over has a slope of ~ 0 and 

G″ show a minimum at the intermediate frequency (Chamberlan and Rao, 1999; Clark and 

Ross-Murphy, 1987). The strength of gel could be appreciated by the magnitude of G′ in the 

range of several k Pa, and by the great differences between G′ and G″. The differences also 

indicate a strong gel in the present case with G′ >> G″ (Chenite et al., 2001). 

The small deformation oscillatory measurements enable a distinction to be made 

between entanglement networks, strong, and weak gels. Polymer networks can be devided 

into chemically cross-linked materials (gel) and entanglement networks. Gels are formed by 

various of routes including cross-linking high molecular weight linear chains or 

polymerization of oligomeric multifunctional precursors. Entanglement networks are formed 

by topological interaction of polymer chains, which depend on concentration and intrinsic 

viscosity of the polymer. 

Figure 8 Variation of the phase lag (δ) with frequency (ω) for typical materials. The upper 

limit is represented by Newtonian fluid (δ= π/2) and the lower limit by a Hooke 

solid (δ=0) 

Source: Steffe (1996b) 

43

Typical spectra of G′ and G″ for entanglements networks (pseudo gel) as the 

frequency decreased. There is a crossover in G′ and G″, at very low frequency. In the 

terminal zone (at low frequency) G′ and G″ flow as high viscosity liquid. Whereas true gels 

posses G′ is higher than G″ through frequency sweep. At small strain both strong and weak 

gel systems give a G′ > G″ with both moduli largely independent of frequency. However, the 

strain dependence of these two classes of materials is very different, since strong gels rupture 

and fail, while weak gel recover and flow (Ross-Murphy, 1995). 

12.1 Strain or stress sweep 

A strain or stress sweep can be conducted by varying the amplitude of the input 

signal at a constant frequency is used to determined the limits of linear viscoelastic behavior 

by identifying a critical value of the sweep parameter.. The values of the strain amplitude are 

verified in order to ensure that all measurement are performed within the linear viscoelastic 

region, such that the storage (G′) and loss modulus (G″) are independent of the strain 

amplitude. Storage and loss moduli versus the sweep paprameters are plot in Fig. 9. Some 

experiments prefer to plot combined materail functions such as the complex modulus or the 

complex viscosity. In the linear region (Fig. 9.) rheological properties are not strain or stress 

dependent. The strain and stress sweeps have been used to differentiate weak and strong gel. 

Strong gel may remain in the linear vicoelastic region over greater strain than weak gels. 

Figure 9 Typical response to a strain or stress sweep showing the linear viscoelastic region 

defined by the critical value of the sweep parameter 

Source: Steffe (1996b) 

44

12.2 Frequency sweep 

The frequency sweep shows how the viscous and elastic behavior of the material 

changes with the rate of application of strain or stress. In this test the frequency is increased 

while the amplitude of the input signal (stress or strain) is held constant. Materials usually 

exhibit more solid like characteristics at higher frequencies. Frequency dependent G′ and G″ 

of solution and gel are measured in the range of frequency at controlled constant temperature. 

The gelation temperature determines as the temperature at which both G′ and G″ follow a 

power law (G′α ω n and G″α ω n ) with the same exponent n. The gelation time is also 

determined as the time. A dilute solution shows G″ larger than G′ over the entire frequency 

range. Concentrated solution shows G′ and G″ curve crossover at the middle of the 

frequency range indicating solid-like behavior at high frequency (Steffe, 1996b). In sol- gel 

transition, G′ shows greater sensitivity to frequency and increases faster than G″. The 

intersection point of G′ and G″ is defined as the gel point (Ross-Murphy, 1991). Another 

criterion use to indicate gel point when plots log G′and G″ against log ω are parallel over 

wide range of frequency (ω) (Winter and Chambon, 1986). 

In frequency sweep experiment within the linear viscoelastic strain range, the 

relative magnitudes of G′ and G″ can classify the rheological behavior of food into three types 

as below (Okechukwu and Rao, 1998). 

a) Biopolymer solution (dilute or concentrate); G′ and G″ show less 

pronounced dependence on frequency. At low frequency G″ is always higher than G′, which 

at the lowest frequency, G′α ω 2 and G″α ω. As frequency or concentration is increased, G′ 

increases faster than and G″, and then displays crossover. At low frequency, dispersion 

shows liquid like behavior and changes to solid-like at high frequency. The value of G′ at 

high frequency is known as the plateau modulus. 

b) Weak gel: G′ and G″ is almost independent of frequency, and possible G″ / 

G′ is about 10 -1 

c)True gel: G″ / G′ would be about 10 -2 

45

12.3 Temperature sweep 

To determine gelation temperature, the temperature at the rapidly increase of G′ 

indicates the gelling temperature (Chenite et al, 2001). The temperature at which tan δ is 

rapid decreased indicates the on set of gelation (Hansen et al., 1990 and 1991; Ikkala, 1986). 

13. Modulated Differential Scanning Calorimetry 

Modulated differential scanning calorimetry (MDSC) is a recently developed 

extension of conventional DSC and a thermo-analytical technique which involves the 

application of sinusoidally complex temperature program. The program is used instead of 

conventional linear heating or cooling temperature (Reading et al., 1992). Whereas DSC is 

only capable of measuring the total heat flow, MDSC provides the total heat flow, the 

reversible (heat capacity of component) and the non-reversible (kinetic component) heat flow. 

(Gallagher, 1997; Hill et al., 1998). 

MDSC technique has received considerable attention in the polymer science field, 

particularly due to the possibility of seeing glass transition in the reversing signal. The 

reversing signal is isolated from overlapping thermal event such as endothermic relaxation 

peaks, which can be seen in the non-reversing response. The advantages of MDSC are 

disentangling overlapping phenomena, improving resolution, enhancing sensitivity, and 

giving a good precision in heat capacity (Reading et al., 1994). 

In addition, the reversing and non-reversing signals reveal the thermodynamic and 

kinetic characteristics of transition, respectively. Examples of event associated with nonreversing 

signals are irreversible processes (e.g., molecular relaxations, cold crystallization, 

evaporation, thermoset cure etc.) and non-equilibrium phase transitions (e.g., melting, 

crystallization and reorganization). The reversing event involves reversible transitions such 

as glass transition and simultaneous crystallization (Gallagher, 1997; Wunderlich, 1997). 

The application of MDSC is to study non-reversible process, such as desolvation, 

degradation and polymorphic conversion as well as in the study of recrystallization 

phenomenon (Rabel et al., 1999). The choice of MDSC experimental parameters must be 

carefully made in MDSC experiments. As a poor choice could be resulted in an inaccurate or 

misleading data. Factors that affect the measured data include the choice of modulation 

46

parameters such as the scan rate (heating rate or degree increase/minute), modulation period 

frequency (time to complete one cycle) and amplitude (magnitude of sigmoidal temperature 

cycling) the quality of the sine wave, the calibration of the data and the pan type (Hill et al., 

1998). MDSC experiments required much slower heating rate (typically 1-5 o C/min) than 

usually used in DSC. Large modulation period are recommended for measuring glass 

transitions since they give more accurate heat capacity measurements. In addition, large 

temperature amplitudes will increase the signal-to-noise ratio and so the data improvement 

(Hill et al., 1998). 

Operation conditions of the MDSC for optimizing the endothermic baseline shift 

associated with the glass transition are scan rate of 5 o C/min with an amplitude of + 1 o C over 

modulation period of 60 or 100 sec. Both the higher scan rate and higher modulation period 

results in a more distinguishable glass transition (Bell and Touma, 1996). The thermal 

responses of starch gelatinization are significantly governed by the frequency and heating 

rate. The temperature on set (To) and peak temperature (Tp) increases as frequency and 

heating rate increased. Tp and gelatinization temperature increases with rising heating rate 

rather than modulation period. In addition, increasing modulation period causes no 

significant influenced on total enthalpy but results in increased reversing and decreased nonreversing 

response. As to the heating rate effects, the size of endothermic peak increased with 

increasing heating rate. Total, reversing and non-reversing enthalpy changes with different 

heating rate (Lai and Lii, 1999). 

Glass transition (Tg) is a physical change in an amorphous material promoted by the 

addition of heat and/or the uptake of plasticizers. Below Tg, a material is in a rigid glassy 

state, which shows high internal viscosity whereas, molecular mobility and diffusion are 

virtually non-existent. Above Tg, amorphous material becomes a rubbery and demonstrates a 

decreases viscosity, and increase in the number and magnitude of molecular motion. The 

glass transition, being reversible, can be differentiate from irreversible change, such as the 

endothermic relaxation of amorphous materials, gelatinization, recrystallization and protein 

denaturation (Bell and Touma, 1996). 

47

1. Raw Materials 

MATERIALS AND METHODS 

Materials 

1. Jerusalem artichoke tubers (Helianthus tuberosus) were obtained from Research 

and Development Institute for Agricultural Systems Under Adverse Conditiona (IASAC) 

which growing at Kanchanaburi research station, Kanchanaburi Province, Thailand. Details 

of raw material handling is presented in section 4. 

2. Dried suflower heads (Helianthus annus) were obtained from Oil Crop subdivision 

of Department of Agricultural extension 

3. Commercial inulin powder Raftiline ® ST and Raftiline ® HP were obtained from 

Helm Mahabun Co. Ltd., 

4. High amylose starch (HYLON ® VII) (70% amylose) was obtained from National 

Starch and Chemical Company, Thailand. 

5. High amylopectin starch (AMIOCA ® ) (98% amylopectin) from National Starch 

and Chemical Company, Thailand. 

6. Normal Corn starch from A.E. Staley Manufacturine company, Decatur, IL. USA. 

2. Chemical Reagents 

1. NaOH solution 400 g/l (40M), Kanto chemical Co., INC. Cat. No. 37901-08 

2. Sodium acetate trihydrate (HPLC grade), Scharlau So0030 

3. Glucose - D(+)-Dextrose anhydrous, Fluka 

4. Fructose D(-) Levulose, Fluka 

5. Sucrose, Sigma 

6. 95 % Ethanol 

3. Equipments and Instruments 

1. High Performance anion exchange chromatography with pulsed amperometric 

detector (HPAEC-PAD). Dionex Bio LC (Sunnyvale, CA, USA) with Chromeleon TM 

software version 6.2 from Dionex. Chromatographic system consisting of : 

48

1.1 ED 50 Pulsed amperometric detector with gold working electrode and 

silver chloride as a reference electrode 

1.2 AS 50 Auto sampler 

1.3 Gradient pump 

1.4 Liquid chromatography module 

1.5 Eluent degas module 

1.6 Column Carbopac PA1 analytical (2x250 mm) 

1.7 Column Carbopac PA1 guard (2x50 mm) 

2. Oscillatory Rotation Rheometer VISCOTECH Rheometer controlled strain 

rheometer (Rheological ® instruments AB, ATS Rheosystems, NJ at Whistler Center for 

Carbohydrate Research, Department of Food Science, Purdue University. 

3. Differential Scanning Calorimeter with modulated mode DSC 2920 Modulated 

DSC TA Instruments NewCastle, DE at Whistler Center for Carbohydrate Research, 

Department of Food Science, Purdue University. 

4. Texture analyzer TA.XT2i ® Stable Microsystems texture expert, from Texture 

Technologies, Scarsdale, NY at Whistler Center for Carbohydrate Research, Department of 

Food Science, Purdue University. 

5. Scanning Electron Microscopy (SEM) Model JSM 5600LV, JEOL Ltd., Japan 

6. Light microscope Leitz-Laborlux 12 POL-Binocular, Germany at Whistler 

Center for Carbohydrate Research, Department of Food Science, Purdue University. 

7. Rapid Visco Analyse (RVA) Newport Scientific Pty. Ltd. Marriedwood, Sydney. 

Australia. 

8. Vaccum rotary evaporator: Rotavapor R152 Buchi and Rotavapor R-114 Buchi 

9. Overhead Stirrer : IKA Labortechnik Eurostar basic with paddle 

10. Hot air oven 

11. Refrigerator 

12. Refregirated centrifugae: Sorvall RC 50 Plus with Rotor F-16/250 

13. Shaking water bath WB22 MEMMERT ® 

14. Magnetic stirrer 

15. Filter membrane 0.45 µm Satorius cellulose acetate 

16. Freeze dryer: FD 2.5 Heto 

17. Hand refractometer (Atago) 

49

1. Chemical Analysis 

1.1 Total soluble solid 

Methods 

Total soluble solid was measured by hand refractometer and expressed as the degree 

brix. The Jerusalem artichoke tubers were crushed into small pieces and pressed. Juice was 

immediately measured by hand refractometer (Van Waes et.al., 1998). 

1.2 Dry matter 

Dry matter was determined before extraction according to the method AOAC 984.25 

(1990). The Jerusalem artichoke tubers were chopped into small pieces and dried at 105 o C 

for 24 h. 

2. Analysis of Inulin Characteristic by HPAEC-PAD 

The distribution of degree of polymerization (DP) and carbohydrate profile were 

analyzed by high performance anion exchange chromatography with pulsed amperometric 

detector (HPAEC-PAD) using Dionex BioLC (Sunnyval, CA, USA) and equipped with a 

pulsed amperometric detector (ED 50). 

The 200 µl of inulin extract (according to 3.) was adjusted to 25 ml and then filtered 

through 0.45 µm cellulose acetate membrane. The diluted inulin extract was injected to 

column by autosampler (AS50). The chromatographic conditions were conducted as 

following: 

Analytical column: CarboPac PA 1 anion exchange column (2 x 250 mm) in 

combination with a CarboPac PA 1 guard column 

Eluents: 150 mM Sodium hydroxide (NaOH) as eluent A, 150 mM Sodium hydroxide 

(NaOH)/500 mM Sodium acetate (NaAc) as eluent B with linear gradient 

Flow rate: 0.25 ml min –1 

Injection volume: 25 µl. 

50

The gradient conditions was programmed to obtain a separation of high DP chains as 

following 

Time (min) Eluent A (%) Eluent B (%) 

0-15 100 0 

15-45 100 to 40 0 to 60 

45-90 10 to 10 60 to 90 

90-110 10 to 0 90 to 100 

110-120 0 to 100 100 to 0 

120-130 100 0 

All gradient solution was linear step. The concentration of sodium hydroxide were 

kept constants to ensure an optimal pH for the analysis (Van Waes et al., 1998). Eluent B, 

containing sodium acetate was mixed increasingly to activate separation of the high DP of 

inulin chain. 

Pulsed amperometric detector (PAD) was equipped with a gold working electrode and 

silver chloride as reference electrode. The potentials and time periods for the pulsed were as 

below. 

Time (sec) Potential (V) Integration 

0.00 0.1 

0.20 0.1 Begin 

0.40 0.1 End 

0.41 - 2.0 

0.43 - 2.0 

0.44 0.6 

0.50 - 0.1 

Detection potential was 0.1 V. Other potentials were used for electrode cleaning. 

High and low potential was applied to eliminate the gold oxide at the surface of working 

electrode to avoid electrode fouling (Cataldi et al., 2000). Relative percentage of the 

composition of sugars and inulin were calculated based on the peak area from chromatogram 

as integrated by the Chromeleon TM software version 6.2 from Dionex. Quantification of each 

DP inulin was limited due to the lack of appropriate standard inulin at specific DP. 

Nevertheless, the relative percentage of DP would reflect changes occur due to maturity, 

storage condition, extraction, and the other parameters involved. In addition, it gave the 

insight information on distribution and population of different inulin DP. 

51

3. Inulin Extraction from Jerusalem Artichoke Tubers 

Inulin was extracted by hot deionized water by modified the method from Van Waes 

et al., (1998). Jerusalem artichoke tubers were washed and steamed at atmospheric pressure 

for 15 min (Laurenzo, 1999). The cooked tubers were crushed into small pieces. Eighty-five 

grams deionized water at 85 o C was added to 11.5g crushed tubers. The slurry was shaken at 

130 rpm at 85 o C for 1 h in a water bath. After cooling to room temperature the total weight 

was adjusted to 100g with deionized water. The samples were then filtered and centrifuged 

for 20 min at 12,000 xg. The supernatant was frozen and stored at -20 o C for analysis. The 

samples were thawed in water bath at 40 o C until clearly before analysis by HPAEC-PAD. 

4. Effect of Harvest Time, Storage Temperature and Storage Time on Jerusalem 

Artichoke Inulin 

For the first year crop, Jerusalem artichoke was planted in winter on January 18, 2001 

at Kanchanaburi research station of Research and Development Institute for Agricultural 

Systems Under Adverse Conditions (IASAC), Kasetsart university. The first flowering was 

in early April, 2001. Jerusalem artichoke tubers (JAT) were harvested in late summer on June 

19, 2001 as the maturity was 21 weeks from planting. At this period of harvesting the stems 

and leave were about 50% dried. 

For second year crop, Jerusalem artichoke was planted in early winter on November 

22, 2001 at Kanchanaburi research station of Research and Development Institute for 

Agricultural Systems Under Adverse Conditions (IASAC), Kasetsart university. The first 

flowering was on January 15, 2002. Jerusalem artichoke tubers were harvested at 3 different 

periods: 16, 18 and 20 weeks after planting. The first maturity was harvested in early summer 

on March 7, 2002. The second and third maturity was harvested on March 21, 2002 and April 

3, 2002, respectively. 

Jerusalem artichoke tubers from first year crop were dug and placed in nylon bags in 

the field. Transportation from research station to laboratory was made at ambient temperature 

within a day of after harvested. Jerusalem artichoke tubers from second year crop were kept 

in ice-cube bucket during transportation from research station to laboratory within a day of 

after harvested. 

52

All tubers were washed and soaked in chlorinated water (200 ppm) for 30 min to 

eliminate soil and reduce microorganism. Some samples were selected for fresh tuber 

analysis on the harvested date. The remaining tubers were packed in sealed polyethylene 

bags (0.075-mm thickness) and kept in duplicated at three temperature treatments. The 

storage temperatures were 2,-18 and –40 o C for the first year crop and 2, 5 and-18 o C for the 

second year crop. These tubers were analyzed for inulin composition at 2 weeks intervals. 

One hundred and fifty grams of tuber were taken randomly from each pack for inulin 

extraction and analyzed by HPAEC-PAD. The data from samples which taken to analyze for 

inulin at 2 weeks were compared with the fresh tubers. Data were analyzed by multivariate 

analysis of variance (MANOVA) one way fixed factor, Duncan multiple range tests was 

calculated for multiple mean comparisons at a significance level of *P

were 15 min for one treatment and 1 hour for another treatment. The experimental was 3 x 3 

x 2 factorial in CRD where type of solvent, solvent-solid ratio and time were the factors. 

Extraction process shown in Fig10. Jerusalem artichoke tubers were washed and 

steamed at atmospheric pressure for about 10 min. (Laurenzo et al.,1999) The steamed tubers 

were crushed and transferred to the hot solvent. The slurry then placed into a water bath at 

85 o C with shaken at 130 rpm and control specific temperature through extraction. After 

cooling to room temperature, a total weight was adjusted to 100g by deionized water. The 

samples were then filtered with fine screen and centrifuged for 10 min at 12,000 xg. The 

clear supernatants were transferred to evaporate flask and evaporated under vacuum on a 

rotary evaporator at 40 o C to concentrate and remove ethanol from the dilute extracts. The 

concentrated juice was made up volume to 25 ml with deionized water and stored at -20 o C for 

analysis. The samples were thawed in water bath at 40 o C until solution was clear before 

analysis of inulin characteristic. 

Figure 10 Inulin extraction process diagram 

Jerusalem artichoke tubers 

Steaming 

Crushing 

Pouring into hot solvent (85 o C) 

Control temp. at 85 o C and shaking at 130 rpm 

for 15 min or 1 h 

Filtration 

Centrifuge at 12,000 xg, 20 min 

Evaporation under vacuum at 40 o C 

54

7. Effect of Solvent on Inulin Precipitation 

To study the effect of solvent on inulin precipitation, the inulin solution was extracted 

from Jerusalem artichoke by deionized water in the ratio of solid:liquid, 1:3 at 85 o C for 1 h as 

Fig.10. The extracted inulin was evaporated under vacuum at 40 o C to about 30 o Brix. The 

inulin was purified or isolated from the extract by water precipitation and/or ethanol 

precipitation. 

7.1 Water precipitation 

The concentrated inulin extract was cooling down to 4 o C for 24 hours without 

stirring (Berghofer et al., 1993b). Inulin was separated by centrifuged at 900xg, 15 min. The 

pallets were freeze-dried. 

7.2 Ethanol precipitation 

Fifty ml of the concentrated inulin extract was added slowly with 21.5, 50 and 

115 ml of cool 95 % ethanol to the final ethanol concentration of 30%, 50% and 70% (v/v) for 

precipitation. During ethanol adding the mixture was immediately stirred at 900 rpm for 3 

min to prevent large fragments of white precipitate adhered to the flask. The flasks were 

covered with parafilm and one stored at room temperature (25 o C) and another one at 4 o C to 

help complete precipitation for 24 hours. Inulin was separated by centrifugation at 900 xg, 15 

min. The pellet was suspended once with the same concentration ethanol and centrifuged 

again. The white precipitate was freeze dried. The experiment was 3 x 2 factorial in CRD 

where concentration of ethanol and temperature were the factors. 

The freeze dried inulin was ground with blender to fine particle and sieving 

through 60 mesh. Purified inulin and supernatant from both methods was analyzed for inulin 

profile by HPAEC-PAD. 

8. Physicochemical Properties of Inulin and Mixed Gel 

Inulin has been used as fat replacer in food that contains starch but little is know 

about the interaction of starch and inulin. Interactions of inulin with other food component 

55

will need to be investigated to determine the types of interaction, functional properties and 

characteristics for useful of application. 

Inulin samples, Raftiline ® HP from Orafti obtained from Helm Mahabun Co.Ltd 

(inulin HP), and inulin extract from Jerusalem artichoke (inulin JAT) were used for these 

experiments. Both samples were sieved through 60 mesh (250 µm) for controlling particle 

size. Other gelling agent were hylon, corn starch and amioca. 

8.1 Solubilization of inulin 

Water solubility of inulin HP and inulin JAT was measured as the effect of 

temperature at 20, 50, 60, 70, 80 and 90 o C. At each experiment temperature, 10 ml of 

deionized water was heated and control the specified temperature throughout the experiment. 

Inulin was slowly added to hot water and stirred with magnetic bar at constant speed until 

undissolve particles were found in the solution after continuing stirring 2 min (Kim et al., 

2001). This was the saturated point of inulin at each temperature. Inulin-water mixture was 

then vacuum filtrated with Whatman No.1 filter paper in the buchner funnel. The buchner 

funnel was controlled at the same temperature as solubilized temperature by water circulate 

through buchner. The inulin on the filter paper was dried at 105 o C and weighed for the excess 

inulin. The excess inulin was subtracted from amount of added inulin, for the known amount 

of soluble inulin. 

8.2 Concentration of inulin for gel formation 

Inulin HP and inulin JAT solution was prepared by RVA as method 8.3 and then 

poured in cylinder and stand to cool down at room temperature. The concentration of inulin, 

which can form gel, was measured by volumetric gel index (VGI). The VGI was calculated 

as the volume of gel formed over total volume multiplied by 100 (Kim et al., 2001). The VGI 

number indicates the degree of gel formation. 

Figure11 Definition of VGI. 

Total volume 

Liquid 

Gel 

Volumetric Gel Index (VGI) = Volume of gel x100 

Total volume 

56

8.3 gel preparation 

Sample preparation for rheological measurement and pasting properties were 

done by using a Rapid ViscoAnalyser (RVA) (Newport Scientific Pty. Ltd., Marriedwood 

NSW, Australia) to control temperature, agitation speed and evaporation loss. 

Inulin HP and inulin JAT solution (15, 18, 20,22 and 25 % w/w, 10 g of total 

weight) was prepared by dispersed inulin powder in deionized water and equilibrated at 50 o C 

for 1 min, heated at 10 o C/min to 80 o C, maintain at that temperature for 5 min, and then heated 

up to 90 o C at 2.5 o C/min for totally dissolved under 500 rpm shearing speed. The temperature 

profile of RVA was shown below. 

Profile for preparing inulin gel by RVA: 

Time (H:M:S) Type Value ( o C) or (RPM) 

0:0:0 Temp 50 

0:0:0 Speed 960 

0:1:0 Speed 500 

0:1:0 Temp 50 

0:4:0 Temp 80 

0:8:0 Temp 80 

0:13:0 Temp 90 

For the mixed gels, there were combination of Hylon VII, Inulin HP or inulin 

JAT, Amioca and corn according to the design below. 

Hylon VII (high amylose starch ~ 70% amylose) and inulin-hylon mixed gel was 

prepared at 20% w/w. 

Mixed inulin-hylon ratio: 1:10 and1:5, 

Amioca starch (high amylopectin starch ~ 98% amylopectin)and inulin-amioca mixed 

gel was prepared at 15% w/w. 

Mixed inulin-amioca ratio 1:10, 1:5 and 3:5 (or 1:1.67) 

corn starch (27% amylose) and inulin-corn mixed gel was prepared at 8% w/w. 

Mixed inulin-corn ratio 1:5 

Mixed inulin-corn-amioca ratio 1:2:3. 

All samples were prepared 10 g of total weight and equilibrated at 50 o C for 1 min, 

heated at 8.5 o C/min to 95 o C, maintained at that temperature for 2.30 min, and then cooled 

57

down to 70 o C for 2 min. At first 10 sec rotating speed of the paddle was 960 rpm, and then 

used speed at 160 rpm along the process. The temperature and speed profile were as below 

Profile for preparing hylon, amioca, corn and mixed system gel by RVA 

8.4 Gel Strength 

Time (H:M:S) Type Value ( o C) or (RPM) 

0:0:0 Temp 50 

0:0:0 Speed 960 

0:0:1 Speed 160 

0:1:0 Temp 50 

0:4:42 Temp 95 

0:7:12 Temp 95 

0:11:0 Temp 70 

0:13:0 Temp 70 

The gel strength of inulin gels was measured as a force in compression test. A 

force-deformation curves were recorded by texture analyzer TA.XT2 at 25 o C. The gel 

samples was prepared in Teflon cylinder molds 1.5 cm diameter 1.5 cm height and kept at 

room temperature for 24 h. The gel samples were placed under the texture analyzer with a 5mm 

diameter flat-faced cylindrical probe. The depth of puncture was 10 mm, the probe speed 

was 0.5 mm/s and trigger force was 1.0 g. The maximal peak force was calculated as gel 

hardness (Kim et al., 2001). The gradient (slope) peak represented gel firmness. The area of 

the peak represented gel toughness. At least 3 replicates of each sample were tested for 

strength. 

8.5 Gel structure 

Gel structures were examined under scanning electron microscopy (SEM) at 10 

kV after dewatered in absolute alcohol and dehydrated by air-drying. Dehydrated specimens 

were fractured, placed in metal stubs and the exposed surface was coated with gold 10-15 ηm 

thickness. Particle characteristics of gel were examined under light microscope by dispersed 

gel on glycerol and stained with aqueous iodine for differentiate inulin and starch particle. 

58

8.6 Rheological properties measurement 

Rheological properties were analyzed by using a VISCOTECH controlled strain 

rheometer (Rheological ® instruments AB, ATS Rheosystems, NJ). The parameters in this 

study were type of inulin (inulin HP and JAT), amylose (Hylon ® ), amylopectin (Amioca ) 

and different proportion of amylose and amylopectin. Each type of inulin was tested in 

combination with amylose and amylopectin in different ratio. High amylose corn starch 

(Hylon ® VII, amylose~ 70%) and high amylopectin waxy corn (Amioca , Amylopectin~ 

98%) were used in this experiment. The conditions were as following: 

- inulin Raftiline ® HP and Inulin JAT concentration from 8.2 

- Interaction between inulin and amylose, inulin-hylon mixture at total 

concentration 20% w/w; hylon, inulin-hylon ratio 1:10 and 1:5. 

- Interaction between inulin and amylopectin, inulin and amioca mixture at total 

concentration 15% w/w; amioca, inulin-amioca ratio 1:10, 1:5 and 3:5 (or 1:1.67). 

- Interaction between inulin, amylose and amylopectin (corn starch), Inulin and corn 

mixture at total concentration 8% w/w; corn, inulin-corn ratio 1:5 and inulin-corn-amioca 

ratio 1:2:3 

Mixed gel was prepared as in method 8.3, amylose and/or amylopectin were 

heated up to gelatinization temperature and cool down to 70 o C. Sample from RVA was 

immediately transferred to rheometer cell. Sample size was maintained constant using 1 ml a 

pipette. Steady shear and oscillatory rheological properties was measured using pressure 

sealed plate-plate cell (Fig. 12). Moisture evaporation was controlled by the application of air 

to sealed cell plate-plate control pressure in the cell. Stainless parallel plate was 20 and 25mm 

diameter. The gap was set at 1 mm. To avoid slippery between the rheometer plates and 

the gel, the surface of the two plates was covered with No.6 sand paper no.6 

The complex viscosity (η*), storage modulus (G′) and loss modulus (G′′) of 

solution and gel were measured. Inulin solution was determined in steady shear (flow test) at 

each temperature (70, 50, 30 and 20 o C). Rheological property of inulin mixed gel was studied 

using dynamic shear rheometer with plate and plate probe. Oscillatory shear test was 

59

conducted at different temperature in wide frequency range 0.01-10 Hz. Rheological 

measurement performed at constant temperature and in wide frequency range. 

Sealed cell plate-plate 

Air supply 

Figure 12 Controlled strain rheometer with sealed plate-plate cell. 

8.6.1 Measuring the viscosity of inulin solution in constant rate 

Hot inulin solution was a low viscosity liquid-like. Viscosity solution was 

measured at 70,50,30 and 20 o C. The measurement cell was heated to 70 o C and then 1 ml 

sample was added. Temperature and shear rate were controlled. 

Effect of temperature on viscosity at constant shear rate; sample was 

measured at shear rate 64.26 1/s and temperature was decreased from 70 o C to 20 o C at 2 o C 

/min. For the effect of shear rate on viscosity at each temperature; sample was measured at 

shear rate 14.01-297.0 1/s while the temperature was controlled at specified temperature. 

8.6.2 Measuring the modulus as a function of strain 

Pressure and 

temperature 

control unit 

Strain sweep were run to determine the linear viscoelastic region of the 

sample. Inulin solution was not tested by strain sweep because inulin solution was a low 

viscosity and liquid like. Strain sweep was determined at 1 Hz and the strain range was 

60

etween 0.01-100%. Oscillatory testing was performed at the temperature of 10, 30 and 50 o C 

at the constant frequency of 1 Hz. The maximum strain, which not destroy the gel structure, 

was selected to be an appropriate strain value for using in the modulus experiments in 8.6.3. 

8.6.3 Measuring the modulus as a function of temperature 

To determine gelation temperature, oscillatory measurement was 

performed at 1 Hz frequency and at a maximum strain value from 8.6.2, while the 

temperature was reduced from 70 to 20 o C at a constant rate of 1 o C/min. The dynamic shear 

storage modulus (G′) at each temperature was recorded. The temperature at the rapidly 

increase of G′ indicated the gelling temperature (Chenite et al., 2001). 

8.6.4 Measuring the modulus and complex viscosity as a function of frequency 

To determine the values of G′ and G′′ as a function of frequency was 

performed at a range between 0.01-100 Hz, with the maximum strain value obtained from 

8.6.2. Oscillatory testing was performed at a temperature of 10, 30 and 50 o C (Chenite et al., 

2001; Ivanov et al.,2001). 

8.7 Thermal properties measurement 

Samples were kept at room temp (25 o C) for 24 h before measured. Melting 

temperature (Tm ), glass transition (Tg) and crystallization temperature (Tc) were measured 

from gel sample. Exact 2 to 10 mg of gel was hermetically sealed separately into aluminum 

DSC pans. The DSC was operated in modulated mode (MDSC) equipped with a refrigerated 

cooling system (RCS). MDSC was performed over a temperature range of 20 to 120 o C, 

1 o C/min scan rate, with amplitude + 1 o C over a modulation period of 60 sec. The DSC cell 

was calibrated for baseline using empty pans of matched weight and for temperature, enthalpy 

and heat capacity using indium (Tm=156.6 o C) as standard. 

This allowed the determination of both Tg and Tm. Tg was taken as inflection 

points of reversible heat flow curves and Tm was taken as peak values of endothermic heatflow 

curves. Crystallization temperature was collected as peaks of exothermic heat flow 

curves (Ivanov et al., 2001). 

61

RESULTS AND DISCUSSIONS 

1. Effect of Harvest Time on Jerusalem Artichoke Inulin 

Jerusalem artichoke has more tall and stiff stems with numerous leaves and normally 

develops tubers 4 to 6 weeks after planting. The number of tubers per plant increases until 

flowering. After flower initiation, the stem lose their sink activity and the stem inulin is 

translocated to the tubers (Frese,1993; Meijer et al., 1993 and Zubr and Pedersen, 1993). The 

Thai grown cultivar has ginger like tubers and white brown skinned (Fig. 13). 

A) B) 

Figure 13 Jerusalem artichoke stems and tubers. A) Jerusalem artichoke stem 16 weeks 

maturity, B) Jerusalem artichokes tubers at 20-weeks maturity from Kanchanaburi 

Research station. Thailand. 

The dry matter of tubers from second crop increased with maturity from 19.63% to 

24.77% at 16 to 20 weeks, respectively (Table 9). Carbohydrate content of Jerusalem 

artichoke tubers is related to dry matter and reaches a maximum at the end of growth (Ben 

Chekroun et al., 1994). Total soluble solids were about the same in each maturity stage. 

62

However, the composition of the sugars was different. Fructose content increased rapidly up 

to 9-fold from 0.34% to 3.0% in the 20-week tubers compared to those at 16 weeks. Sucrose 

content only slightly increased in late maturity tubers. Glucose was more abundant at early 

maturity and decreased from 0.96% to 0.26% at late maturity. Edelman and Jefford (1968) 

indicated that fructan synthesis was controlled by sucrose-sucrose fructosyltransferase (SST) 

and fructan-fructan fructosyltransferase (FFT). SST is the first step of fructan synthesis in 

growing tubers, using sucrose as the primary source of fructosyl donor and releasing free 

glucose. Glucose usually appeared in growing tubers and decreased to a very low level in the 

mature tubers. The increase in free fructose could indicate increased activity of inulinase as 

the tuber grows older (Limami and Fiala, 1993). 

Table 9 Dry matter, total soluble solids and relative percentage composition of sugars and 

inulin of Jerusalem artichoke tubers with different maturity. 

Composition Maturity (weeks) 

16** 18** 20** 21* 

Dry matter (%) 19.63 b 

23.55 a 

24.77 a 

31.58 

Total soluble solid (%) 23.35 a 

22.50 a 

23.50 a 

Relative (%) 

25.00 

Glucose 0.96 a 

0.80 b 

0.26 c 

3.91 

Fructose 0.34 c 

0.74 b 

3.00 a 

0.67 

Sucrose 7.51 b 

7.50 b 

8.76 a 

2.52 

Inulin DP 3-10 47.01 a 

47.15 a 

47.28 a 

32.47 

DP 11-20 29.19 a 

29.56 a 

26.71 b 

32.67 

DP 21-30 10.24 a 

9.99 a 

9.52 a 

16.86 

DP >30 4.79 a 

4.30 a 

4.48 a 

10.94 

* First crop: Jarusalem artichoke planted on January, 2001 and harvested in April 2001 

** Second crop: Jerusalem artichoke planted in November, 2001 and harvested on March 

2002 

Means with different letters in a row are significantly different at *P

period, while the DP 11-20 component decreased in the 20-week tubers. This suggests that 

inulin composition changed with maturity. The decrease in DP 11-20 with increase in free 

fructose and sucrose might be caused by the depolymerization of fructan by fructan 

exohydrolase (FEH) (Edelman and Jefford, 1968). It has been shown that FEH exhibited a 

high affinity for fructan with a DP up to 30 (Bonnett and Simpson, 1993). Ben Chekroun et 

al. (1994), using HPLC and TLC techniques, found that only the late maturity tubers had 

maximum contents of polyfructans. The drying period of Jerusalem artichoke leaves and 

stems was accompanied by a small increase in reducing sugar, which was due to 

depolymerization of high molecular weight carbohydrate molecules (Schorr-Galindo and 

Guiraud, 1997). Tubers at 16 and 18 weeks contained high DP fructan (DP > 10; 44.22% and 

43.85%) compared to 20 weeks (40.71%) where inulin depolymerization may occur. 

Jerusalem artichoke tubers at 16-18 weeks were preferable for the production of inulin 

because it had high DP fraction and low content of sucrose and fructose. When considering 

dry matter content we recommended that 18 weeks after planting seemed to be the optimum 

maturity for high molecular weight inulin from Jerusalem artichoke grown in Thailand. 

The relative composition of carbohydrate in first crop Jerusalem artichoke tubers of 

DP 3-10, DP11-20, DP 21-30, DP>30, glucose, sucrose and fructose were 30%, 30%, 15%, 

10%, 5%, 4% and 1% respectively. The main portion of inulin from first crop Jerusalem 

artichoke was DP < 20 which was approximate by 60% of total carbohydrate. The main 

composition of inulin in the second crop Jerusalem artichoke was also DP < 20 which was 

approximately 75% of total carbohydrate. 

The year and planting condition also affected the composition of inulin (Table 9). 

Both crops were planted in the same area, but were different in the amount of water supply 

mainly with rainfall. The first crop was planted on January until June 2001 which had 

average temperature of 29.02 o C and had average rainfall of 47.0 mm. The flowering period in 

April until harvested had high amount of rainfall (176.9 mm). The second crop was planted 

in November until April 2001, which had average temperature of 27.7 o C and had average 

rainfall of only 11.4 mm. The flowering period in January until harvested had the amount of 

rainfall of 52.9 mm. For the first crop, water was supplied to plant until harvest, yielding full 

flowering crop. Whereas in the second crop, there was water shortage during flowering stage 

which gave an incomplete flowering crop. The effect of these different water 

supplementation was reflected by the amount of dry matter, total soluble solid and inulin 

composition in the tubers between the first and second crop (Table 9). 

64

The dry matter of 21-weeks first crop tubers was 31.58% and total soluble solid was 

25% which higher than 20-weeks second crop tubers of 24.77% and 23.5%, respectively. 

These may indicate that the amount of water supply affected the quality of tubers, especially 

during flowering period. Water stress conditions might cause an incomplete synthesis and 

translocation of photosynthesis materials from stem into tuber. Because, during flowering, the 

inulin is relocate from stem to tuber (Meijer et al., 1993; Zubr and Pedersen, 1993). Frese 

(1993) found water supply appeared to be the major factor influencing inulin yield and inulin 

DP or fructose/glucose ratio, and also promoted growth of stem and leaves to expense of 

tuber growth. Low rainfall and a very high temperature reduced dry matter yields (Kiehn and 

Chubey, 1993). 

The composition of carbohydrate in 21-weeks first year crop tubers was different 

from 20-weeks second crop tubers (Table 9). Glucose content in first crop tubers was 3.91% 

which 15-folds higher than second crop. Fructose and sucrose was 0.67% and 2.52% which 

4.5-folds and 3.5-folds less than second year crop tubers, respectively. Inulin DP 3-10 and 

DP > 10 was 32.47% and 60.47% while in the second crop tuber was 47.28% and 40.71%. 

These contents might indicate that water supply had more effect on inulin synthesis. The 

inulin synthesis might continue because the glucose content was still high. Also, inulin 

deplymerization might be delay because there were high content of high DP and the fructose 

and sucrose content were low. The high content of sucrose and low inulin DP > 10 in second 

crop tubers might be indicate the FFT activity. Luscher et al. (1996) found that sucrose will 

inhibit 1-FFT activity for synthesis high DP inulin. This may cause the low content of high 

DP inulin in second crop tubers. 

Beside differences in the composition of inulin and dry matter was affected by harvest 

time and water supply. The physical characteristic of tubers was also affected. The 20-weeks 

tubers in second crop had spongy texture (Fig. 14B) which had lost their crisp and juicy 

nearly the base of the stem (Fig. 14A). 

The results from both crop tubers indicated that the quality of tubers and carbohydrate 

compositions did not merely depend on harvest time but also on the plating condition either. 

Thus, the physical characteristics of tubers, drying period of leaves and stems might be 

considered for harvesting beside the date of planting until harvest. 

65

Spongy part 

A) B) 

Figure 14 Spongy texture of 20-weeks tubers, A) area of spongy texture, B) Spongy texture. 

2. Effect of Storage Temperature on Jerusalem Artichoke Inulin 

Tubers stored at 2 o C and 5 o C for 12 weeks were still firm, crisp, and exhibited no 

sign of spoilage or sprouting. The effect of storage temperature on dry matter was more 

pronounced. There were significantly different in the amount of dry matter kept at different 

storage temperature (Table 10). Jerusalem artichoke tubers stored at -40 o C maintained highest 

dry matter content as compared to -18 o C and 2 o C storage condition. The 2 o C samples 

exhibited lowest dry matter content. A slight loss of reserve dry matter could due to tissue 

respiration. 

There were no significant changes in total soluble solid content with storage time up 

to 12 weeks. A slight increase in total soluble solid of the 2 o C Jerusalem artichoke tubers 

was probably due to moisture loss after long term storage. The total soluble solid of the - 

18 o C Jerusalem artichoke tubers, however, was lowest throughout 12 weeks storage time. 

This could due to some soluble solid loss with drip during thawing just prior the 

measurement. The freezing and frozen storage at -18 o C would result in larger ice crystal 

formation in the tissue, hence more structural damage during thawing than the -40 o C freezing 

and frozen storage tuber. Cold storage at 2 o C would not pose tissue damage from 

temperature effect. 

The effect of storage temperature on the distribution profile of inulin DP (Fig. 15) 

was more pronounced with longer storage time. A gradual increase in sucrose and DP 3-10, 

and a decrease in DP > 10 fractions were seen in inulin composition extracted from 2 o C and 

66

5 o C stored tubers, particularly at 5 o C after 4 weeks of storage (Fig. 15B, 15C). Composition 

of inulin extracted from -18 o C stored tubers remained stable throughout the storage time (Fig. 

15A). Most enzymatic and chemical reactions were drastically reduced or stopped at freezing 

temperatures, while Jerusalem artichoke tissue metabolism could continue, at a slow rate, 

even at 2 o C storage temperature. Cold storage would therefore retard undesirable changes in 

the inulin characteristics for a certain period of time, e.g. 4 weeks at 5 o C in this study. Frozen 

storage would maintain Jerusalem artichoke tubers and their inulin quality for much longer 

time. 

Table 10 Dry matter and total solid of 21-weeks maturity first crop Jerusalem artichoke 

tubers stored at different temperatures for 12 weeks. 

Storage time 

Dry matter (%) Total solid (%) 

(weeks) 2 o C -18 o C -40 o C 2 o C -18 o C -40 o C 

2 27.19 b 

4 27.17 c 

6 27.19 c 

8 30.24 b 

10 27.64 c 

12 28.92 b 

30.88 a 

27.84 b 

29.29 b 

30.50 b 

31.59 a 

29.05 b 

31.29 a 

30.18 a 

31.03 a 

32.85 a 

30.08 b 

31.44 a 

25.00 a 

27.50 a 

24.00 a 

29.50 a 

27.00 a 

29.25 a 

22.00 b 

19.50 b 

21.50 a 

22.00 c 

22.75 b 

19.75 c 

Means with different letters in a row are significantly different at *P 10) and monosaccharide at 5 o C as compared to 2 o C. Higher storage temperature (5 o C) 

encouraged more changes in inulin DP profile toward low molecular weight compounds. 

Modler et al. (1993) also found that higher storage temperature encouraged breakdown of 

inulin and utilization of monosaccharide formed from the breakdown, presumably due to 

higher respiration and other metabolic activities. Significant increased in sucrose and DP 3- 

10 corresponded with significant decrease in higher DP inulin (DP >10) and monosaccharide. 

The lower proportion of monosaccharide, sucrose, and DP 3-10 in frozen samples (-18 o C) 

compared to fresh tubers was probably due to drip loss during thawing, which is in agreement 

67

with the preliminary results found on reductions in total soluble solids. Increase in the high 

DP proportion of the -18 o C sample therefore reflected the losses of those low molecular 

weight fractions. 

Relative (%) 

Figure 15 Relative percentage (mean ± SD) of sugars and inulin profiles from 20-week 

maturity Jerusalem artichoke tubers stored at -18 o C (A), 2 o C (B), and 5 o C (C) for 

10 weeks. 

70 

60 

50 

40 

30 

20 

10 

0 

0 2 4 6 8 10 

70 

60 

50 

40 

30 

20 

10 

0 

70 

60 

50 

40 

30 

20 

10 

0 

monosaccharide sucrose 

DP3-10 DP>10 

0 2 4 6 8 10 

0 2 4 6 8 10 

Storage time (weeks) 

A) 

B) 

C) 

68

Table 11 Relative percentage of sugar and inulin composition of 21-weeks maturity first crop 

Jerusalem artichoke tubers stored at different temperature for 12 weeks. 

Composition Storage temperature ( o C) 

(relative %) fresh -40 -18 2 

Monosaccharide 6.15 c 

Glucose 5.34 b 

Fructose 0.81 d 


DP 3-10 29.29 c 

DP>10 59.23 a 

DP 11-20 30.39 c 

DP 21-30 16.68 a 

DP>30 12.12 a 

7.00 b 

6.04 a 

0.96 c 

2.93 c 

33.81 b 

55.96 b 

31.99 a 

15.42 b 

8.55 c 

6.79 b 

5.58 a 

1.22 b 

2.92 c 

33.41 b 

56.93 b 

31.37 b 

15.38 b 

10.18 b 

11.71 a 

3.39 c 

8.32 a 

10.51 a 

43.46 a 

34.33 c 

24.25 d 

7.31 c 

2.77 d 

Means with different letters in a row are significantly different at *P10 44.42 b 

DP 11-20 29.19 b 

DP 21-30 10.24 b 

DP>30 4.79 b 

1.77 b 

1.37 a 

0.40 c 

3.87 c 

40.56 b 

53.82 a 

34.34 a 

13.16 a 

6.32 a 

7.82 a 

0.84 a 

6.99 a 

11.26 a 

45.03 a 

35.89 c 

25.77 c 

7.09 c 

3.03 c 

2.97 b 

0.10 a 

2.88 b 

8.99 b 

46.47 a 

41.63 b 

23.85 c 

12.06 a 

5.72 a 


Table 13 Relative percentage of sugar and inulin composition of 18-weeks maturity second 

crop Jerusalem artichoke tubers stored at different temperature for 12 weeks. 

Composition Storage temperature ( o C) 

(relative %) fresh -40 -18 2 

Monosaccharide 1.53 a 


Fructose 0.74 a 


DP 3-10 47.15 b 

DP>10 43.85 b 

DP 11-20 29.56 a 

DP 21-30 9.99 b 

DP>30 4.30 b 

2.08 a 

1.79 a 

0.30 a 

3.63 c 

6.69 a 

1.40 ab 

5.29 a 

9.60 d 

39.23 42.80 c 

55.05 a 

34.28 a 

14.91 a 

5.86 a 

41.03 b 

26.73 a 

10.78 b 

3.52 c 

3.59 a 

1.11 ab 

2.48 a 

8.25 ab 

48.50 

39.13 c 

26.94 a 

9.32 b 

2.39 d 


DP 11-20 26.71 b 

DP 21-30 9.52 c 

DP>30 4.48 b 

1.26 b 

0.71 a 

0.55 c 

4.33 c 

40.82 c 

53.61 a 

31.67 a 

15.29 a 

6.65 a 

2.51 ab 

0.45 a 

2.05 ab 

8.22 b 

46.33 b 

42.95 b 

27.48 b 

11.93 b 

3.54 b 

1.05 b 

0.05 a 

1.01 bc 

10.23 a 

57.06 a 

31.00 c 

23.64 c 

6.77 d 

1.27 c 


The chromatograms of inulin from Jerusalem artichoke which stored at -18 o C, 2 o C 

and 5 o C had different pattern (Fig. 16). The chromatograms of inulin from Jerusalem 

artichoke tubers which stored at -18 o C and fresh tuber (Fig. 16A-B) had the same pattern, 

thoughout the storage time. Whereas the chromatograms of inulin from Jerusalem artichoke 

tubers which stored at 2 o C and 5 o C had extra small peak. These indicated that the inulin 

distribution profile was changed by the effect of storage temperature. In the frozen storage, 

the inulin compositions of stored tubers were quite similar to in fresh tubers for long time 

storage (Table 15-16, 18, 21 and 24). See section 3. 

Detector response (µC) 

0.180 _C 

0.150 

0.125 

0.100 

0.075 

0.050 

0.025 

fru 

glu 

suc 

5 

10 

15 

20 

-0.020 

-0.0100 

0 20 40 60 80 100 0 20 40 60 80 100 

0.140 _C 

0.120 

0.100 

0.080 

0.060 

0.040 

0.020 

0.000 

glu fru 

suc 

5 

4 ′ 

3 ′ 

5 ′ 

10 

15 

20 

A) 

C) 

0.0600 _C 

Figure 16 HPAEC-PAD Chromatograms of inulin and new fructan series from 20-week 

0.0500 

0.0400 

0.0300 

0.0200 

0.0100 

0.0000 

0.100 _C 

-0.020 

-0.010 min 

0 20 40 60 80 100 0 130 20 40 60 80 100 

0.080 

0.060 

0.040 

0.020 

maturity Jerusalem artichoke tubers as fresh tuber (A), and stored at -18 o C (B), 

2 o C (C), and 5 o C (D) for 8 weeks. Series of small peaks in (C) and (D) indicate 

new fructan series. Glu = glucose, Fru = fructose, Suc = sucrose, Number of peak 

represents DP fractions 

suc 

suc 

Time (min) 

5 

5 

4 ′ 

3 ′ 

5 ′ 

10 

10 

15 

15 

20 

20 

25 

B) 

D) 

71

3. Effect of Storage Time on Jerusalem Artichoke Inulin 

The effect of storage time on DP distribution profile can be seen in Fig. 15. The 

reduction in DP > 10 and the increases in sucrose and DP 3-10 were significant after 4-6 

weeks of storage. Table 15-26 also demonstrates the effect of storage time on relative 

percentage of sugar and inulin composition. The effect of storage time on inulin composition 

was more dominated in cold storage temperature. The compositions of inulin in Jerusalem 

artichoke tubers which stored at 2 o C and 5 o C changed with time of storage while the one at 

-18 o C and -40 o C were rather constant. Table 17 at storage temperature 2 o C fructose and 

sucrose increased rapidly at 6 weeks and DP 3-10 increased later on. At this storage time, the 

content of long-chain inulin such as DP > 10 was decreased because it might depolymerized 

to free fructose, sucrose and short-chain inulin. Storage tubers at 2 o C for longer time resulted 

in decreasing the amount of long chain inulin. For the samples which stored at -18 o C and 

-40 o C, the amount of each sugar and inulin compositions were constant through the 12 weeks 

storage (Table 15-16). 


Jerusalem artichoke tubers with different storage time at -18 o C. 

Composition Storage time (weeks) 

(relative %) 0 2 4 6 8 10 12 

Monosaccharide 6.15 d 

Glucose 5.34 e 

Fructose 0.81 e 

Sucrose 4.79 a 

DP 3-10 29.92 e 

DP 11-20 30.39 c 

DP 21-30 16.68 a 

DP >30 12.16 a 

7.82 b 

6.42 c 

1.40 a 

2.52 d 

31.28 d 

5.48 e 

4.47 f 

1.01 d 

3.48 b 

35.29 a 

30.94 31.04 b 

16.44 a 

11.00 ab 

15.10 d 

9.62 c 

7.79 b 

6.83 b 

0.96 d 

2.96 c 

31.17 d 

31.82 a 

15.95 b 

10.34 bc 

8.41 a 

7.29 a 

1.13 c 

2.77 cd 

32.33 c 

31.66 a 

15.54 c 

9.27 c 

4.58 f 

3.50 g 

1.09 c 

3.41 b 

34.86 a 

30.86 bc 

15.36 cd 

10.95 ab 


Table 26 demonstrated the effect of storage time on second crop Jerusalem artichoke 

tubers stored at 5 o C up to 10 weeks. Fresh harvested Jerusalem artichoke tubers contained 

about 40.71%, 47.28% and 8.76% of inulin with DP > 10, DP 3-10, and sucrose, respectively. 

After 4 weeks of storage significant breakdown of high DP fractions (DP > 10) occurred. At 

the end of 10 weeks storage DP distribution profile of inulin shifted significantly to about 

31.68%, 57.06% and 10.23% of DP > 10, DP 3-11 and sucrose, respectively. Therefore, longterm 

storage would inevitably affect inulin composition, i.e. degradation to shorter chains. In 

our case, four weeks storage time seemed to be the limit at 5 o C in order to maintain high DP 

inulin (Fig. 15). 


Jerusalem artichoke tubers with different storage time at -40 o C. 


(relative %) 0 2 4 6 8 10 12 

Monosaccharide 6.15 e 

Glucose 5.34 c 

Fructose 0.81 c 


DP 3-10 29.92 ab 

DP 11-20 30.39 c 

DP 21-30 16.68 a 

DP >30 12.16 ab 

8.40 b 

6.58 a 

1.81 b 

2.28 e 

29.64 b 

30.44 c 

16.64 a 

12.63 a 

15.65 a 

6.47 ab 

9.18 a 

7.22 a 

33.05 a 

23.25 d 

11.66 e 

9.21 de 

7.36 c 

6.14 b 

1.22 bc 

2.77 cde 

32.32 a 

31.53 ab 

15.80 c 

10.24 cd 

8.28 b 

6.69 a 

1.59 b 

2.56 de 

31.61 a 

31.75 a 

15.48 cd 

10.37 cd 

6.39 e 

5.6 c 

0.79 c 

3.21 c 

32.15 a 

30.89 bc 

16.22 b 

11.15 bc 



Jerusalem artichoke tubers with different storage time at 2 o C. 


(relative %) 0 2 4 6 8 10 12 

Monosaccharide 6.15 f 


Fructose 0.81 f 

Sucrose 4.79 d 

DP 3-10 29.92 e 

DP 11-20 30.39 b 

DP 21-30 16.68 a 

DP >30 12.16 b 

8.52 e 

7.17 a 

1.35 d 

5.53 c 

29.52 e 

27.15 d 

16.45 ab 

12.84 a 

6.23 f 

5.25 bc 

0.98 e 

2.99 e 

32.67 c 

31.44 a 

15.95 b 

10.76 c 

14.76 a 

5.13 c 

9.63 a 

9.78 b 

31.01 d 

28.69 c 

9.13 c 

6.65 d 

12.59 b 

4.23 d 

8.36 b 

9.85 b 

30.65 d 

28.23 d 

8.50 d 

10.23 c 

10.40 d 

3.53 e 

6.87 c 

9.81 b 

40.72 b 

26.54 e 

6.72 e 

5.85 e 

Means with different letters in a row are significantly different at *P30 4.79 c 

0.83 b 

0 a 

0.83 cd 

4.32 abc 

46.17 ab 

31.10 b 

11.77 bc 

5.86 ab 

4.85 a 

0.77 a 

4.09 a 

6.49 ab 

43.23 bcd 

29.62 b 

10.79 cd 

5.06 bc 

4.10 ab 

2.64 a 

1.46 b 

5.21 abc 

44.16 abc 

30.74 b 

10.60 d 

5.23 bc 

2.25 ab 

1.37 a 

0.88 bcd 

2.43 c 

43.93 abc 

33.56 a 

12.04 b 

5.80 ab 

2.90 ab 

1.795 a 

1.12 bc 

3.91 bc 

41.57 cd 

33.95 a 

12.45 ab 

5.23 bc 



crop Jerusalem artichoke tubers with different storage time at 2 o C. 


(relative %) 0 2 4 6 8 10 12 

Monosaccharide 1.29 e 

Glucose 0.96 d 

Fructose 0.34 f 

Sucrose 7.51 f 

DP 3-10 47.01 a 

DP 11-20 29.19 a 

DP 21-30 10.24 ab 

DP >30 4.79 c 

8.23 d 

3.22 b 

5.03 e 

9.15 e 

38.98 b 

26.63 ab 

11.02 a 

6.08 ab 

15.53 a 

5.77 a 

9.80 b 

10.01 d 

37.67 b 

22.27 cd 

9.45 b 

5.11 bc 

8.23 d 

2.05 c 

6.19 d 

9.89 d 

39.35 b 

24.42 bc 

11.11 a 

7.03 a 

12.13 c 

2.11 c 

10.02 ab 

12.90 ab 

31.56 a 

23.76 bc 

9.77 b 

5.01 bc 

13.68 c 

3.18 b 

10.51 a 

10.68 c 

45.70 a 

20.49 d 

6.76 c 

2.67 d 

Means with different letters in a row are significantly different at *P30 4.79 d 

9.15 b 

2.59 ab 

6.56 b 

8.15 cd 

36.05 d 

27.42 b 

12.21 a 

6.99 ab 

9.7 b 

2.85 a 

6.86 b 

9.10 c 

39.01 c 

25.21 cd 

10.95 bc 

6.07 bc 

6.40 c 

1.11 b 

5.29 c 

9.30 c 

39.44 c 

26.13 c 

11.51 ab 

7.21 a 

12.1 a 

0.79 bc 

11.23 a 

12.24 a 

40.49 bc 

24.63 de 

7.15 d 

3.46 e 

2.34 de 

0.28 bc 

2.06 e 

10.82 b 

41.78 b 

25.12 cde 

12.63 a 

7.33 a 



crop Jerusalem artichoke tubers with different storage time at -18 o C. 


(relative %) 0 2 4 6 8 10 12 

Monosaccharide 1.53 bc 

Glucose 0.80 ab 

Fructose 0.74 ab 


DP 3-10 47.15 a 

DP 11-20 29.56 de 

DP 21-30 9.99 e 

DP >30 4.30 b 

2.4 ab 

1.35 a 

1.05 a 

5.66 c 

48.04 a 

30.04 d 

9.73 ef 

3.85 b 

3.61 a 

1.41 a 

2.21 a 

6.45 b 

48.36 a 

28.75 e 

8.99 f 

3.86 b 

2.42 ab 

1.41 a 

1.00 ab 

5.43 c 

44.17 b 

31.47 c 

11.12 d 

5.36 a 

0.69 c 

0.08 b 

0.61 bc 

4.44 d 

43.97 b 

33.22 b 

12.35 c 

5.34 a 

1.73 bc 

1.43 a 

0.30 c 

3.29 e 

38.38 c 

36.93 a 

14.01 b 

5.73 a 

Means with different letters in a row are significantly different at *P30 4.30 bc 

1.92 b 

0 c 

1.92 b 

3.35 b 

48.97 a 

29.87 a 

10.83 b 

5.05 a 

6.85 b 

2.31 ab 

4.54 b 

10.31 a 

45.77 b 

19.05 c 

8.65 c 

4.42 ab 

14.20 a 

2.98 a 

11.22 a 

11.23 a 

4.90 b 

1.36 abc 

3.54 b 

10.36 a 

45.32 bc 47.82 abc 

4.08 b 

0.98 abc 

3.22 b 

7.90 ab 

42.10 d 

20.16 bc 24.06 abc 28.23 ab 

6.26 d 

2.84 e 

9.29 c 

3.70 cd 

12.65 a 

5.06 a 





(relative %) 0 2 4 6 8 10 12 

Monosaccharide 1.53 c 

Glucose 0.80 cd 

Fructose 0.74 de 

Sucrose 7.50 c 

DP 3-10 47.15 c 

DP 11-20 29.56 a 

DP 21-30 9.99 c 

DP >30 4.30 d 

8.36 a 

2.51 ab 

5.86 a 

8.52 bcd 

42.62 d 

26.30 bc 

9.67 c 

4.54 cd 

8.19 a 

0.95 cd 

7.25 a 

9.16 bc 

39.47 f 

25.91 bc 

11.02 b 

6.27 b 

9.40 a 

2.98 a 

6.43 a 

9.60 b 

40.83 e 

25.21 c 

9.66 c 

5.32 c 

3.75 b 

1.61 bc 

2.14 bc 

15.74 a 

64.19 a 

14.38 d 

1.63 d 

0.37 f 

1.26 c 

0.90 d 

1.17 bc 

6.87 e 

42.5 d 

27.5 b 

14.07 a 

7.81 a 

Means with different letters in a row are significantly different at *P30 4.48 c 

0 c 

0 c 

0 d 

4.60 b 

51.38 a 

29.59 c 

10.04 d 

4.40 c 

1.52 b 

0.84 a 

0.68 bc 

5.35 c 

43.88 c 

31.86 b 

12.02 c 

5.38 b 

1.88 b 

0.93 a 

0.95 b 

4.75 b 

44.39 c 

31.48 b 

12.16 c 

5.36 b 

0 c 

0 c 

0 d 

3.02 b 

42.01 d 

35.27 a 

14.06 b 

5.70 b 

1.26 b 

0.71 ab 

0.55 c 

4.33 b 

40.82 d 

31.67 b 

15.29 a 

6.65 a 





(relative %) 0 2 4 6 8 10 

Monosaccharide 3.26 d 

Glucose 0.26 c 

Fructose 3.00 d 

Sucrose 8.76 c 

DP 3-10 47.28 a 

DP 11-20 26.71 b 

DP 21-30 9.52 ab 

DP >30 4.48 b 

6.28 c 

2.48 b 

3.80 c 

8.77 c 

41.28 c 

27.20 a 

16.45 a 

5.60 a 

10.22 a 

3.26 a 

6.96 b 

9.97 c 

41.73 c 

24.31 c 

9.03 ab 

4.76 b 

6.40 c 

0.59 c 

5.82 b 

10.28 a 

44.40 b 

22.11 d 

10.83 ab 

5.91 a 

7.72 b 

3.62 a 

4.10 c 

9.88 b 

48.36 a 

23.94 c 

7.72 c 

2.40 d 

2.51 d 

0.45 c 

2.05 e 

8.22 d 

46.33 ab 

27.48 a 

11.93 ab 

3.54 c 


0.44 d 

2.22 ab 

2.65 bc 

4.9 b 

40.6 d 

31.89 a 

13.08 a 

6.91 a 

10.73 a 

3.56 a 

7.16 a 

10.15 ab 

40.72 d 

24.76 ab 

9.17 b 

4.49 b 

4.93 b 

0.5 ab 

4.43 ab 

14.29 a 

60.14 a 

16.43 b 

3.12 d 

1.11 d 

0.18 d 

0 b 

0.18 c 

10.03 ab 

60.73 a 

22.24 ab 

5.01 cd 

1.92 c 

1.05 d 

0.05 b 

1.01 bc 

10.23 ab 

57.06 b 

23.64 ab 

6.77 c 

1.27 d 


Further examination of the HPAEC-PAD chromatogram revealed that not only was 

the distribution profile of inulin changed but also new carbohydrates were formed (Fig. 16). 

Series of small peaks, especially from tubers stored at 2 o C and 5 o C, were found as illustrated 

in Fig. 16C-D, while samples stored at -18 o C retained their original chromatographic pattern 

as fresh tuber (Fig. 16B). Fig. 17 illustrated the presence of second fructan series, designated 

as DP 3′, DP 4′ etc., up to DP 19. A new second fructan series, DP 2′-DP 5′, was found in 

fresh Jerusalem artichoke in trace amounts by Ernst et al. (1996). The amount of inulo-n-ose 

present on a tissue depended on the physiological condition of plant. In chicory there was 

low inulo-n-ose during growing season but was rather high after just 3 week of cold storage. 

These were characterized as inulo-n-ose that contained only β (2→1) linked fructose 

molecules without end glucose moiety (Ernst et al., 1996). These inulo-n-ose products, for 

example 2′ for inulo-bi-ose and 3′ for inulo-tri-ose, might be derived by hydrolysis of 

terminal glucose or fructose molecules from large inulin molecules. These new fructans were 

probably formed during inulin mobilization in plant tissue (Ernst et al., 1996). Our findings 

indicate that the second fructan series occurred in Jerusalem artichoke tubers during cold 

storage, but not under frozen storage at -18 o C. Previous study (Ernst et al., 1996) by gel 

permeation suggested that DP 2 (sucrose) and 2′ (inulo-bi-ose), DP 3 and 3′, etc. were of the 

same molecular size. However, their retention times on the HPAEC-PAD chromatogram 

were quite different. DP 2′ eluted after DP 3 (1-kestose), 3′ eluted after DP 4 (nystose) and so 

on (Ernst et al., 1996). The new series inulin is assumed to be indentical with the inulin series 

minus the terminal glucose moieties. The differences in chromatographic behavior between 

glucose-containing inulo-oligosaccharides and those consists of fructose only (especially 

applied) to the DP 2 components sucrose and inulobiose, the sucrose was eluted very much 

earlier than the inulobiose (Vogel, 1993). 

Partial hydrolysis of pure 4′ new fructan resulted in 3′, 2′ and fructose but no 1kestose, 

sucrose and glucose. Therefore the new fructan had no terminal or internal glucose 

moiety in molecule. Analysis of carbon linkage using methylation method found that new 

fructan had only fructose moieties with substitution occurring only on carbon number 1 and 2. 

This new fructan was different from isomer of fructan from cheatgrass which has both of β– 

2,1-linked and β-2,6 linked fructose (Chatterton et al.,1993b). 

79

Detector response 

0 

0 

0 

glu 

fru 

suc 

3 

10 40 

6 ′ 

8 9 10 

7′ 

11 

12 

13 

14 

40 50 60 

4 

3’ 

Time (min) 

5 

6 7 8 9 

4’ 

5’ 

6’ 7’ 

10 11 

A) 

B) 

80 

15 

16 

12′ 

17 

13′ 

18 19 

14′ 15′ 

20 21 22 23 

16′ 17′ 18′ 19′ 

Figure 17. HPAEC-PAD chromatograms of inulin extracted from 18-weeks maturity 

Jerusalem artichoke tubers and stored at 2 o C for 8 weeks, which demonstrate the 

new fructan series. The inulin series is marked as 3, 4, 5 etc. The new fructan 

series is marked as 2′, 3′, 4′, etc. A) First part of chromatogram displays up to DP 

11, B) Continuing chromatogram to display DP > 8. 

Table 27-29 show the amount of inulo-n-ose designated as DP 3′ up to DP 17′ in 

relative percentage from tubers kept at 2 o C and 5 o C up to 12 weeks. Inulo-n-ose increased 

with time of storage. The amount of inulo-tri-ose (3′) increased about 4 fold from 4 weeks to 

12 weeks of storage for 16-weeks maturity tubers (Table 27). Inulo-tri-ose (3′) and inulo- 

tetra-ose (4′) were the predominant new fructans found throughout the 12 week study period. 

Inulo-tri-ose (3′) and inulo-tetra-ose (4′) were first found after 2 weeks of tuber storage at 

B)

5 o C. Higher DP of inulo-n-ose was observed as storage time increased. Ernst et al. (1996) 

found a second fructan DP 2′ up to DP 18′ in chicory stored at 2-4 o C for 3 weeks. However, 

DP 2′ was not found in this study. There were no second fructan series found in the frozenstored 

tubers. Freezing temperatures could cease hydrolytic activity in the tubers as seen in 

Fig. 16B. If the second fructan series was to be minimized, inulin should be extracted before 

indigeneous hydrolysis occured. Cold (non-freezing) storage of Jerusalem artichoke tubers 

could result in degradation of high DP inulin to short chain inulin, with the formation of these 

β (2→1) linked fructans without end glucose moiety. 

Table 27 Relative percentage of inulo-n-ose as compared to sugar and inulin composition of 

16-weeks maturity second crop Jerusalem artichoke tubers stored at 2 o C and 5 o C up 

to12 weeks. 

Storage 

inulo-n-ose 

conditions 3′ 4′ 5′ 6′ 7′ 12′ 13′ 14′ 15′ 16′ 17′ 

2 o C 

2 weeks ND ND ND ND ND ND ND ND ND ND ND 

4 weeks 1.56 d 

1.30 d 

1.01 d 

0.86 d 

0.48 d 

0.15 d 

0.19 c 

0.22 b 

0.22 b 

ND ND 

6 weeks 2.15 c 

1.96 c 

1.63 c 

1.44 c 

1.21 c 

0.21 c 

0.56 b 

0.58 a 

0.47 a 

0.37 b 

8 weeks 2.79 b 

2.35 b 

1.87 b 

1.66 b 

1.43 b 

0.86 b 

0.78 ab 

0.57 a 

0.53 a 

0.40 a 

10 weeks 2.03 c 

1.58 d 

1.17 d 

0.86 d 

0.24 d 

ND ND ND ND ND ND 

12 weeks 4.54 a 

4.04 a 

3.31 a 

2.64 a 

2.06 a 

1.04 a 

0.91 a 

0.64 a 

0.46 a 

0.31 c 

5 

ND 

o C 

2 weeks 0.50 f 

0.47 f 

ND ND ND ND ND ND ND ND ND 

4 weeks 0.94 e 

0.97 e 

0.75 e 

0.65 e 

0.35 e 

ND 0.20 e 

0.20 e 

ND ND ND 


1.53 d 

1.28 d 

1.14 d 

0.94 d 

ND 0.26 d 

0.33 d 

0.36 c 

0.30 d 

8 weeks 3.29 a 

2.88 a 

2.14 b 

1.80 b 

1.45 b 

0.26 b 

0.72 c 

0.43 c 

0.47 b 

0.34 c 

10 weeks 1.99 c 

1.97 c 

1.81 c 

1.47 c 

1.20 c 

0.31 ab 

0.82 b 

0.72 b 

0.59 a 

0.46 b 

ND 

12 weeks 2.91 b 

2.73 b 

2.32 a 

1.94 a 

1.58 a 

0.29 a 

0.90 a 

0.75 a 

0.62 a 

0.48 a 

ND 

ND = not detected 

Means with different letters in a column are significantly different at *P



to12 weeks. 

Storage 

inulo-n-ose 

conditions 3′ 4′ 5′ 6′ 7′ 12′ 13′ 14′ 15′ 16′ 17′ 

2 o C 


4 weeks 0.72 bc 


8 weeks 2.06 ab 



5 o C 





10 weeks 1.86 a 


0.42 e 

0.68 d 

1.69 c 

2.06 b 

2.15 b 

2.63 a 

0.43 c 

1.04 ab 

1.15 ab 

1.69 a 

1.65 a 

1.88 a 

0.26 c 

0.54 c 

1.21 b 

1.77 a 

1.99 a 

2.16 a 

0.28 e 

0.23 d 

0.46 d 

1.01 c 

1.44 b 

1.89 a 

1.91 a 

0.23 d 

0.74 0.65 c 

0.92 c 

1.23 b 

1.78 a 

1.71 a 

0.81 b 

0.85 b 

1.57 a 

1.55 a 

82 

ND ND ND ND ND ND ND 


ND 0.18 c 

0.21 c 

0.21 c 

ND ND 

0.26 0.38 b 

0.48 b 

0.40 b 

0.23 b 

ND 

ND 0.99 a 

0.86 a 

0.55 a 

0.54 a 

ND 


0.28 ab 

0.81 ab 

1.22 ab 

1.66 a 

0.93 ab 


ND ND ND 0.09 c 

ND ND 

ND 0.17 b 

0.22 b 

0.23 b 

0.19 b 

ND 


0.26 0.67 a 

0.75 a 

0.63 a 

0.45 a 

ND 


0.33 c 

0.45 b 

0.30 c 

1.28 a 

1.29 a 





to 10 weeks. 

Storage 

inulo-n-ose 

conditions 3′ 4′ 5′ 6′ 7′ 12′ 13′ 14′ 15′ 16′ 17′ 

2 o C 


0.34 e 


1.01 d 


2.41 a 


1.83 c 

10 weeks 1.67 2.23 b 

5 o C 


0.31 e 


1.04 d 


1.20 c 


2.35 a 

10 weeks 1.87 b 

2.11 b 

83 


0.66 c 

0.38 c 


1.63 a 

1.35 a 

0.71 0.79 a 

0.61 a 

0.51 a 

0.38 ND 

1.34 b 

1.06 b 

ND 0.25 b 

0.29 b 

0.27 b 

ND ND 

1.65 a 

1.35 a 


0.76 d 

2.04 a 

1.58 c 

1.85 b 


0.69 0.40 ND ND 0.16 0.18 ND ND 

0.57 d 


1.36 b 

1.02 b 


1.45 a 

1.13 a 


0.79 d 

0.86 c 

1.62 b 

1.67 a 



Figure 18 Dried de-seed sunflower head. 

Table30 Proximate composition of dried sunflower head. 

Cultivars Moisture 

(%) 

Protein 

(%) 

Fat 

(%) 

Ash 

(%) 

84 

Carbohydrate 

(%) 

Pacific 33 * 12.28 4.43 1.29 20.16 61.63 

Pacific 33** 11.00 6.42 1.74 19.96 60.88 

Pacific 33*** 14.14 12.39 1.48 19.71 52.28 

Pacific 44*** 12.57 12.43 1.82 18.72 54.46 

Pacific 55*** 12.87 9.18 1.74 20.27 55.94 

SS 3322*** 13.09 13.76 1.52 18.49 53.14 

Mitent*** 13.32 7.44 1.85 21.37 56.02 

* Commercial plot from Saraburi ** Commercial plot from Suphanburi 

*** Demonstration plot 

Proximate analysis of dried sunflower heads of all cutivars was shown in Table 30. 

The compositions were moisture 11.00-14.14 %, protein 4.43-13.76 %, fat 1.29-1.85%, ash 

18.49-21.37 and carbohydrate 52.28-61.63% (Table 33). Carbohydrate was the large of 

portion in dried sunflower head. Dried heads also contained high ash content. Cellulose, 

hemicellulose and pectin might be main carbohydrates. Sunflower heads was known to

Detector Response (µC) 

contain acetyled pectin or low methoxyl pectin. Shi et al., (1996) reported that mature 

sunflower heads contained 150-250 g of pectin per kg head, of which about 25% was water 

soluble. 

Sunflower water extraction was analyzed by HPAEC-PAD as shown in Fig. 19. The 

chromatographic patterns from dried sunflwer head were distinctively different from those of 

inulin extracted from jerusalem artichoke (Fig. 16). The individual peak was eluted after 30 

min to 70 min. Pacific 33 variety had more high DP fraction than other varieties. These may 

imply that the DP of carbohydrate in sunflower head had short range of DP and low content 

of high DP. The chromatograms also exhibited no glucose, fructose and sucrose. Unresolved 

chromatogram suggested mixed composition of high molecular weight carbohydrate with in 

the extract. Separation of any complex polysaccharides might be need prior to further 

characterization of this carbohydrate. 

0.014 _C 

0.010 

0.007 

0.005 

0.002 

0.000 

0.0180 _C 

0.0150 

0.0100 

0.0050 

0.0020 

-0.0020 

0 20 40 60 80 100 0 20 40 60 80 100 

0.0900 _C 

0.0750 

0.0625 

0.0500 

0.0375 

0.0250 

0.0125 

A B 

.0200 _C 

C D 

.0150 

.0100 

0.0050 

-0.0020 

-0.0100 

0 20 40 60 80 100 

0 20 40 60 80 100 

Time (min) 

Figure 19 HPAEC-PAD chromatogram of carbohydrate extract from sunflower head of each 

Cultivars; A) Pacific 33, B) Pacific 55, C) Mitent and D) SS 3322. 

85

Carbon linkage of oligomer can determine from methylation analysis by 

dimethylsulfoxide (DMSO) anion followed by methyl iodide. The resulting partially 

methylated were analyzed by GC-MS. Oligomer structure can further be identified by 

analyzed the products of a partial hydrolysis. The resulting hydrolysated can be analyzed 

directly by HPAEC (Chatterton et al., 1993b). If inulin was presented in dried sunflower 

head, it may be of low content. It could also need to be extracted at a stage of full head 

development, before the dried out period or seed production. Inulin could be depolymerized 

in reserved plant part at the last stage of maturity (Ben Chekround et.al., 1994). Since there 

were little or no inulin presence in these dried sunflower head, further study in the disertation 

will focus on Jerusalem artichoke inulin. 

5. Effect of Solvent Extraction on Inulin Composition of Jerusalem Artichoke 

Inulin from Jerusalem artichoke were extracted by water, 50% ethanol and 80% 

ethanol in the solid: liquid ratio 1:1,1:5 and 1:10 within 15 min and 1 hour at 85 o C. The 

effect of extraction time was tested by independent sample T-test at confidential interval 95% 

and found that there was no significant different for inulin extracts at 15 min and 1 hour for 

all types of solvent and solid: liquid ratio. 

The effect of solvent and solid: liquid ratio were analyzed by multivariate analysis of 

variance, there were no significant different in composition of extracted inulin . Table 31-32 

illustrated the effect of solvent on composition of extracts which were not different for all 

three types of solvent at each solid: liquid ratio. Further examination on the effect of solid : 

liquid ratio in Table 33-35 indicated, there were no effect on the composition of the extract. 

Although, the composition was not significant different (p 30) tended to decrease as the ethanol concentration increased 

(Table 31). The large portion of extract was inulin DP 3-10. High DP inulin (DP > 10) from 

ethanol extraction was slightly low than from water extraction, especially in 80% ethanol 

concentration at 15 min extraction time. The effect of solvent was cleared at 15 min 

extraction for which the differences in composition of the extracts were observed. 

86

There were no effect on sugar and inulin due to solvent, solvent extraction time and 

solvent ratio (Appendix Table 19-20). However, solvent type had some effect as in Table 36. 

Monosaccharide and/or glucose content from 80% ethanol extraction was higher where DP > 

30 was lower than from 50% ethanol and water extraction. 

These results indicated high DP fructan was extracted as the ethanol concentration 

was decreased. Grotelueschen and Smith (1968) extracted fructans from timothy and 

bromrgrass with graded ethanol at room temperature. The maximum DP of fructan (~260) in 

timothy was higher than in bromograss (~26). The percentages of carbohydarates extracted 

from timothy were highest for water extraction, but in case of bromograss the highest was 

found for 65% ethanol extraction. High ethanol concentration also extracted reducing sugars 

and sucrose. Therefore, high DP of fructosans was extracted as the ethanol concentration was 

decreased. Ohyama et al. (1990) extracted inulin from yacon which had low-DP fructans like 

onion with hot 80% ethanol. It was shown that about 90% of dry matter in 80% ethanol 

extract contained with a low molecular weight. Inulin a which was detected in the insoluble 

fraction of 80% ethanol extraction, was significantly low in content and average DP. Ben 

Chekround et al. (1994) used 90% and 50% ethanol for extraction simple carbohydrates and 

polyfructans from Jerusalem artichoke and found that inulin DP from 90% ethanol was lower 

than 8, and from 50% ethanol was higher than 8. BeMiller (1996) mentioned that high 

molecular weight polysaccharides precipitated at high ethanol concentration. Hence, high DP 

inulin might remain in insoluble pulp as Livingston (1990) and Livintons et al. (1993) 

extracted fructan from oats and barley with 80% ethanol and was washed with hot deionized. 

The ethanol extraction contained primarily sugars and DP 3-5 fructan. The pulp of plant 

material contained DP > 6. 

Table 37 showed the high solid: liquid ratio (1:10) was high capable extracted higher 

amount of glucose and DP > 30 than low ratio (1:1). This might be from the diffusion rate 

and mass transfer rate in high liquid portion was more than in thick slurry. 

The extraction inulin with high concentration of ethanol would provide high content 

of reducing sugar, low DP fraction. The high DP fraction may be left in insoluble part or in 

pulp of Jerusalem artichoke tubers. Thus water extraction would provide high DP fraction 

and low content of sugar than ethanol extraction. The high DP fraction may also be possible 

to extract by water extraction of the remaining pulp. 

87

Table 31 Effect of solvent (water, 50% and 80% ethanol) on relative percent of sugar and inulin composition of Jerusalem artichoke tubers extracted 

for 15 min at different solid:liquid ratio. 

Composition Solid:liquid (1:1) Solid:liquid (1:5) Solid:liquid (1:10) 

(relative %) water 50% 80% water 50% 80% water 50% 80% 

Monosaccharide 4.12 + 0.74 6.87 + 2.50 8.11 + 3.87 8.70 + 3.71 9.09 + 4.17 8.41 + 0.46 9.89 + 5.57 8.74 + 4.78 17.04 + 3.65 

Glucose 0.60 + 0.84 2.28 + 0.62 3.18 + 1.70 2.87 + 0.83 3.38 + 1.29 3.75 + 2.59 3.99 + 2.8 3.36 + 2.14 8.23 + 2.25 

Fructose 3.53 + 0.11 4.59 + 1.87 4.93 + 2.17 5.83 + 2.88 5.71 + 2.89 4.66 + 2.13 5.90 + 2.77 5.38 + 2.64 8.81 + 1.40 

Sucrose 8.38 + 2.36 11.21 + 1.56 10.22 + 0.01 9.53 + 0.91 10.56 + 0.19 12.70 + 1.69 10.40 + 0.19 10.7 + 0.70 12.27 + 1.75 

Inulin DP 3-10 46.16 + 3.41 50.11 + 2.95 50.50 + 2.56 49.20 + 1.85 48.14 + 1.85 49.71 + 4.25 47.26 + 0.17 48.92 + 3.49 43.49 + 6.05 

DP 11-20 29.52 + 1.17 23.30 + 3.56 23.08 + 3.27 23.63 + 2.44 23.40 + 2.63 21.44 + 0.04 23.29 + 3.12 23.46 + 3.00 20.75 + 0.23 

DP 21-30 9.32 + 1.61 7.21 + 2.77 6.86 + 2.38 7.26 + 2.08 6.97 + 1.75 6.39 + 1.49 7.15 + 1.80 6.73 + 1.40 5.72 + 0.28 

DP > 30 2.50 + 0.12 1.36 + 0.69 1.19 + 0.74 1.69 + 0.64 1.68 + 0.21 1.34 + 0.69 2.02 + 0.42 1.43 + 0.23 1.18 + 0.09 

Means in a row for each solid: liquid ratio are not significantly different at *P < 0.05 according to Duncan’s Multiple RangeTest. 

93 

88

Table 32 Effect of solvent (water, 50% and 80% ethanol) on relative percent of sugar and inulin composition of Jerusalem artichoke tubers extracted 

for 1 h at different solid:liquid ratio. 

Composition Solid:liquid (1:1) Solid:liquid (1:5) Solid:liquid (1:10) 

(relative %) water 50% 80% water 50% 80% water 50% 80% 

Monosaccharide 6.18 + .01 3.72 + 2.00 6.65 + 3.05 6.41 + 0.82 9.19 + 4.60 8.52 + 5.90 6.34 + 1.15 7.43 + 3.60 9.41 + 1.53 

Glucose 1.41 + 0.65 0.96 + 1.35 2.04 + 0.71 1.57 + 1.27 3.65 + 1.99 0.79 + 0.67 1.45 + 0.81 2.55 + 1.41 2.57 + 0.47 

Fructose 4.77 + 2.67 2.77 + 0.66 4.61 + 2.33 4.84 + 2.11 5.54 + 2.61 4.73 + 2.33 5.20 + 2.00 4.79 + 2.02 6.84 + 1.05 

Sucrose 11.23 + 1.01 11.49 + 1.39 11.37 + 0.89 10.31 + 0.96 10.35 + 0.13 9.73 + 0.34 10.30 + 0.80 10.83 + 0.80 7.11 + 5.79 ns 

Inulin DP 3-10 51.23 +.42 53.59 + 4.65 51.40 + 0.63 49.32 + 2.90 47.56 + 0.60 48.94 + 0.59 49.46 + 2.30 48.55 + 0.88 47.26 + 4.38 

DP 11-20 23.93 + 3.13 23.86 + 2.28 25.22 + 1.39 24.41 + 2.04 23.84 + 2.90 23.37 + 2.83 24.15 + 1.74 23.76 + 2.73 26.09 + 5.06 

DP 21-30 6.68 + 1.61 6.54 + 1.53 6.24 + 1.00 7.70 + 2.23 7.27 + 2.01 7.62 + 2.84 7.70 + 2.09 7.58 + 2.40 7.97 + 2.74 

DP > 30 0.90 + 0.23 0.77 + 0.35 0.60 + 0.84 1.87 + 0.37 1.86 + 0.50 1.81 + 0.52 2.04 + 0.44 1.98 + 0.51 2.15 + 0.78 

Means in a row for each solid: liquid ratio are not significantly different at *P < 0.05 according to Duncan’s Multiple RangeTest. 

94 

89

Table 33 Effect of solid: liquid ratio on relative percent of sugar and nulin composition of Jerusalem artichoke tubers which extracted by water. 

Composition Extraction time 15 min Extraction time 1 hour 

(relative %) 1:1 1:5 1:10 1:1 1:5 1:10 

Monosaccharide 4.12 + 0.74 8.70 + 3.71 9.89 + 5.57 6.18 + .01 6.41 + 0.82 6.34 + 1.15 

Glucose 0.60 + 0.84 2.87 + 0.83 3.99 + 2.8 1.41 + 0.65 1.57 + 1.27 1.45 + 0.81 

Fructose 3.53 + 0.11 5.83 + 2.88 5.90 + 2.77 4.77 + 2.67 4.84 + 2.11 5.20 + 2.00 

Sucrose 8.38 + 2.36 9.53 + 0.91 10.40 + 0.19 11.23 + 1.01 10.31 + 0.96 10.30 + 0.80 

Inulin DP 3-10 46.16 + 3.41 49.20 + 1.85 47.26 + 0.17 51.23 +.42 49.32 + 2.90 49.46 + 2.30 

DP 11-20 29.52 + 1.17 23.63 + 2.44 23.29 + 3.12 23.93 + 3.13 24.41 + 2.04 24.15 + 1.74 

DP 21-30 9.32 + 1.61 7.26 + 2.08 7.15 + 1.80 6.68 + 1.61 7.70 + 2.23 7.70 + 2.09 

DP >30 2.50 + 0.12 1.69 + 0.64 ns 

2.02 + 0.42 ns 

0.90 + 0.23 1.87 + 0.37 2.04 + 0.44 

Means in a row for each extraction time are not significantly different at *P < 0.05 according to Duncan’s Multiple RangeTest. 

95 

90

Table 34 Effect of solid: liquid ratio on relative percent of sugar and nulin composition of Jerusalem artichoke tubers which extracted by 50% 

ethanol. 


(relative %) 1:1 1:5 1:10 1:1 1:5 1:10 

Monosaccharide 6.87 + 2.50 9.09 + 4.17 8.74 + 4.78 3.72 + 2.00 9.19 + 4.60 7.43 + 3.60 

Glucose 2.28 + 0.62 3.38 + 1.29 3.36 + 2.14 0.96 + 1.35 3.65 + 1.99 2.55 + 1.41 

Fructose 4.59 + 1.87 5.71 + 2.89 5.38 + 2.64 2.77 + 0.66 5.54 + 2.61 4.79 + 2.02 

Sucrose 11.21 + 1.56 10.56 + 0.19 10.7 + 0.70 11.49 + 1.39 10.35 + 0.13 10.83 + 0.80 

Inulin DP 3-10 50.11 + 2.95 48.14 + 1.85 48.92 + 3.49 53.59 + 4.65 47.56 + 0.60 48.55 + 0.88 

DP 11-20 23.30 + 3.56 23.40 + 2.63 23.46 + 3.00 23.86 + 2.28 23.84 + 2.90 23.76 + 2.73 

DP 21-30 7.21 + 2.77 6.97 + 1.75 6.73 + 1.40 6.54 + 1.53 7.27 + 2.01 7.58 + 2.40 

DP >30 1.36 + 0.69 1.68 + 0.21 1.43 + 0.23 0.77 + 0.35 1.86 + 0.50 1.98 + 0.51 


96 

91

Table 35 Effect of solid: liquid ratio on relative percent of carbohydrate and inulin composition of Jerusalem artichoke which extracted by 80% 

ethanol. 


(relative %) 1:1 1:5 1:10 1:1 1:5 1:10 

Monosaccharide 

8.11 + 3.87 8.41 + 0.46 17.04 + 3.65 6.65 + 3.05 8.52 + 5.90 9.41 + 1.53 

Glucose 

3.18 + 1.70 3.75 + 2.59 8.23 + 2.25 2.04 + 0.71 0.79 + 0.67 2.57 + 0.47 

Fructose 

4.93 + 2.17 4.66 + 2.13 8.81 + 1.40 4.61 + 2.33 4.73 + 2.33 6.84 + 1.05 

Sucrose 

10.22 + 0.01 12.70 + 1.69 12.27 + 1.75 11.37 + 0.89 9.73 + 0.34 7.11 + 5.79 ns 

Inulin DP 3-10 

50.50 + 2.56 49.71 + 4.25 43.49 + 6.05 51.40 + 0.63 48.94 + 0.59 47.26 + 4.38 

DP 11-20 

23.08 + 3.27 21.44 + 0.04 20.75 + 0.23 25.22 + 1.39 23.37 + 2.83 26.09 + 5.06 

DP 21-30 

6.86 + 2.38 6.39 + 1.49 5.72 + 0.28 6.24 + 1.00 7.62 + 2.84 7.97 + 2.74 

DP >30 

1.19 + 0.74 1.34 + 0.69 1.18 + 0.09 0.60 + 0.84 1.81 + 0.52 2.15 + 0.78 


97 

92

Table 36 Effect of solvent on relative percent of sugar and inulin composition of Jerusalem 

artichoke tubers. 

Composition Solvent 

(relative %) Water 50% EtOH 80% EtOH 

Monosaccharide 6.94 + 2.91 7.50 + 3.41 9.69 + 4.40 

Glucose 1.93 + 1.59 ns 

2.69 + 1.50 ns 

3.42 + 2.72 

Fructose 5.01 + 1.88 4.79 + 1.95 5.76 + 2.19 

Sucrose 10.02 + 1.29 10.85 + 0.83 10.56 + 2.73 

Inulin DP 3-10 48.77 + 2.39 47.80 + 6.40 48.55 + 3.85 

DP 11-20 24.82 + 2.83 23.60 + 2.14 25.82 + 4.75 

DP 21-30 7.63 + 1.68 7.05 + 1.54 6.79 + 1.70 

DP > 30 1.83 + 0.56 1.51 + 0.53 ns 

1.38 + 0.7 ns 

Means in a row are not significantly different at *P 30 1.22 + 0.77 ns 

1.71 + 0.37 1.80 + 0.51 

Means in a row are not significantly different at *P

6. Effect of Solvent on Inulin Precipitation 

The extracted juice contained of mono-, di-, oligosaccharides and high polymers 

carbohydrates. A standard procedure to precipitate gum/hydrocolloid is by slowly adding of 

ethanol (or acetone) to a rapid stirred solution. Polysaccharides do not precipitate well from 

dilute solutions, so certain concentration is necessary. Generally, three volume of 95 % 

ethanol are added (final concentration = 71% ethanol v/v) to separate high molecular weight 

polysaccharides. However, gums are available in wide range of molecular weight. They may 

not precipitate well even by addition of four volumes of ethanol (final concentration = 76% 

ethanol v/v) (BeMiller, 1996). 

Two methods of inulin separation were water and ethanol precipitation (Phelps, 

1965). Water precipitation depended on the fact that many fructosans could be obtained in 

microscopically “crystalline” from by cooling a solution to –15 o C and allowing it to warm up 

to room temperature. The second method depended on the ability of ethanol to precipitate 

inulin from aqueous solution (Phelps, 1965). 

Fifty ml concentrate inulin extract (30 o B), was precipitated by adding water at low 

temperature (4 o C) and by adding ethanol at 4 o C and 25 o C overnight. In ethanol precipitation, 

the solution turned to cloudy when ethanol was added. If it was not stirred quickly, large 

clump of white precipitates occurred and adhered to the flask. The fine particle was 

discovered in the rapid stirring condition. 

Precipitate from water at low temperature was yellow-white color, while precipitate 

from ethanol was bright white. The amount of precipitate from adding of high ethanol 

concentration was higher than from low ethanol concentration and water as illustrated in 

Table 38. Inulin from 70% ethanol precipitation was 12.23-12.42 g, while inulin from 50% 

ethanol, 30% ethanol and water precipitation was 11.03-9.56, 7.39-7.62 and 4.32 g, 

respectively. In addition, total soluble solid in supernatant from 70% ethanol precipitation 

was lowest. This suggested that 70% final ethanol concentration was more effective to 

precipitate the inulin and provide more yield of inulin separation. Berghofer et al. (1993b) 

studied the production of inulin from chicory root in pilot scale. The extract was evaporated 

under vacuum to about 40% (w/w), heated up to 95 o C and then over a period of 30 h, slowly 

cooling down to 4 o C without stirring. Inulin was precipitated in a crystalline form and was 

separated and dried. The isolation of inulin by crystallization appeared to be difficult and 

94

yield was not satisfactory. The residual syrup was found to be rich in low molecular weight 

carbohydrates. 

Table 38 The amount of dried inulin in precipitate fraction. 

Treatment Inulin (g) 

Water, 4 o C 4.32 d + 0.05 

30% final Ethanol concentration, 4 o C 7.62 bcd + 2.35 

50% final Ethanol concentration, 4 o C 9.56 abc + 0.40 

70% final Ethanol concentration, 4 o C 12.42 a + 2.07 

30% final Ethanol concentration, 25 o C 7.39 cd + 1.07 

50% final Ethanol concentration, 25 o C 11.03 abc + 2.74 

70% final Ethanol concentration, 25 o C 12.23 ab + 2.35 


Table 39 illustrated the composition of inulin from ethanol precipitation which did 

not contain sucrose content. The precipitated inulin had DP range from simple sugars to an 

estimated DP of 60. Ku et al. (2003) found that ethanol concentration had effect on the 

efficiency of inulin precipitation. The experiment of Ku et al. (2003) designed by four ratios 

of solvent to inulin solution (1:1; 2:1; 3:1 and 4:1, v/v) were investigated at 4 o C overnight. At 

a ratio of 1:1 (~ 48% final ethanol concentration), there was no precipitation. At a ratio of 2:1 

(~ 63% final ethanol concentration) molecules with high DP began to precipitate. At a ratio 

of 3:1 (~ 71% final ethanol concentration) more of the molecules with high DP precipitated. 

and the molecules of lower DP began to precipitate. Finally at ratio of 4:1 (~ 76% final 

ethanol concentration) molecules with DP 1-18 remained in supernatant. From our data 

(Table 39), inulin can precipitate even in water solution at 4 o C because high DP inulin was 

less water soluble than the low DP. Thus at 4 o C DP > 30 was precipitated by water at 

19.82%. The content of DP > 30 by ethanol precipitation increased as the ethanol 

concentration increased. The content of low DP (DP 3-10) of ethanol precipitated at 4 o C was 

gradual higher than ethanol which high ethanol concentration increased possibility the 

precipitate of low DP. Besides at low ethanol concentration 30% and 50% the precipitate 

occurred. 

Precipitate from ethanol at 4 o C had high content of simple sugars and DP 3-10 than 

water precipitation. These results were similar to Phelps (1965) who found that inulin 

precipitated from 50% final ethanol concentration had high content of DP 2-8 than from water 

precipitation. The water precipitated inulin possessed the least contaminants from fructose 

and ash than inulin from ethanol precipitation. 

For the effect of temperature to ethanol precipitate (Table 39), it found that large 

molecule DP>20 could be better precipitated at 25 o C. By the proportion, low molecular 

weight (DP 3-10) was better separated at 4 o C than 25 o C. At 4 o C, DP 3-10 was the largest 

fraction content which was not at 25 o C. Fig. 20 illustrated the DP distribution profile of the 

precipitate, which had wide range of DP. The number of DP was higher than 60. The 

maximum number of DP was in the range of 60-70. However, due to the limit of detection 

sensitivity by HPAEC-PAD, high DP than 70 could will be presented. At 25 o C, the 

precipitate had low content of DP 4 than precipitate at 4 o C. 

96

Table 39 Effect of final ethanol concentration and temperature on relative percent of sugar 

and inulin composition of precipitate. 

Composition 4 o C 25 o C 

relative % water 30% 

EtOH 



Fructose 3.30 b 


DP 3-10 22.29 a 

DP 11-20 26.89 a 

DP 21-30 24.22 a 

DP > 30 19.82 a 

12.30 a 

0.33 a 

11.98 a 

0.26 a 

38.87 a 

26.11 a 

14.54 a 

7.94 d 

50% 

EtOH 

10.87 a 

0.56 a 

10.31 a 

0.0 a 

70% 

EtOH 

9.53 a 

0.57 a 

8.96 ab 

0.0 a 

31.6 a 8 37.98 a 

26.43 a 

18.64 a 

12.47 b 

25.77 a 

16.34 a 

10.36 bc 

30% 

EtOH 

6.16 a 

0.52 a 

5.65 a 

0.56 a 

25.45 a 

26.70 a 

23.52 a 

18.33 a 

50% 

EtOH 

5.56 a 

0.48 a 

5.05 a 

1.37 a 

25.91 a 

26.78 a 

22.95 a 

17.26 a 

Means with different letters in a row are significantly different at *P 20. Especially, for ethanol precipitation, the high DP > 30 did not remaine in 

the supernatant. The supernatant had high content of low DP. Moreover, it also contained 

second fructans, which were not found in precipitate (Table 41). The second fructans DP 3′- 

DP 7′ was found left in the supernatant. Fig. 21 illustrated the DP distribution profile of 

supernatant, which had the highest DP in the range of 40-50. The content of sugar and low 

DP was high especially for DP 3 and DP 4. The high DP content gradually decreased. 

Livingston (1990) precipitated inulin by adding absolute ethanol to the extract and 

found that the supernatant contained simple sugars and smaller fructans. The white 

precipitate was dissolved in water, then reconcentrating and precipitating twice. Three total 

precipitation resulted in inulin DP>6 and absenced of sugars and smaller fructans (DP 3-5). 

Moreover, the different extracted solvent concentrations yielded different DP of fructan 

precipitate. The alcohol treatment could precipitate large DP and other substances 

(Chatterton et al., 1993). Also, Vogel (1993) eliminated the high amount of mono-, di- and 

97

oligosaccharide by ethanol precipitation. The precipitate contained only component with 

DP>10. 

Table 40 Effect of final ethanol concentration and temperature on relative percent of sugar 

and inulin composition left in the supernatant after precipitation for 1 day. 

Composition 4 o C 25 o C 

relative % water 30% 

EtOH 



Fructose 2.84 a 


DP 3-10 42.44 a 

DP 11-20 24.83 a 

DP 21-30 9.98 a 

DP > 30 1.77 a 

11.80 a 

10.44 a 

1.36 a 

0.0 a 

50.59 a 

24.32 a 

5.45 a 

0.63 a 

50% 

EtOH 

11.68 a 

11.68 a 

0.0 a 

0.30 a 

50.59 a 

28.17 a 

3.31 a 

0.0 a 

70% 

EtOH 

7.03 a 

5.88 a 

1.16 a 

0.91 a 

54.01 a 

31.95 a 

2.97 a 

0.0 a 

30% 

EtOH 

12.28 a 

9.07 a 

5.64 a 

5.92 a 

43.90 a 

23.16 a 

9.56 a 

0.63 a 

50% 

EtOH 

8.51 a 

6.98 a 

0.0 a 

2.78 a 

45.69 a 

24.84 a 

10.62 a 

1.27 a 


Compositions of precipitate from water and ethanol were not significant different 

(Table 39). Precipitate from ethanol had high content of sugars and low DP. This precipitate 

should be washed with the same final ethanol concentration several times to remove some 

sugars and low DP in precipitate fraction if one was desired. 

Preliminary experiment examination of water and 70% final ethanol concentration 

precipitated at 4 o C for 5 days indicated that the composition of precipitate from water and 

ethanol was different. Table 42 demonstrated the results of this experiment. The main 

composition of precipitate was DP 11-20, and ethanol precipitation. Precipitate from water 

contained sugars but there were not contained in ethanol precipitate. The content of DP>10 

of ethanol precipitation was 73.7 which higher than water precipitate was 66.42. DP>30 in 

ethanol precipitate was at 14.91% while in water precipitate was only 7.79%. This result was 

in argument with Livingtons (1990) that inulin which precipitate from absolute ethanol 

consisted of DP>6 and disappeared of fructose. 

Table 42 Effect of precipitation method on relative percent of sugar and inulin composition 

of precipitate which precipitation at 4 o C for 5 day. 

Composition Precipitate Supernatant 

relative % Water 70% final ethanol conc. Water 70% final ethanol conc. 

Monosaccharide 2.15 0 0 12.79 

Glucose 0.77 0 0 5.13 

Fructose 1.37 0 0 7.66 

Sucrose 4.03 0 2.93 12.25 

Inulin DP 3-10 27.42 26.33 62.83 52.72 

DP 11-20 40.33 40.64 28.25 20.70 

DP 21-30 18.30 18.15 4.92 1.55 

DP >30 7.79 14.91 0.72 0 

Supernatant from water and ethanol precipitation for 5 day at 4 o C was quite different. 

Water supernatant did not have monosaccharide and inulin was remained 96.72% which was 

high DP (DP>10) 33.89%. Whereas, ethanol supernatant consisted of monosaccharide, 

sucrose and inulin component 74.95 %, which 22.25%of inulin was DP>10. These results 

were mentioned by Vogel (1993) that mono-,di and oligosaccharides were eliminated be 

ethanol precipitation. 

99

The main composition found in precipitation for 1 day and 5 days was different 

(Table 39 and Table 41). The main composition from 1 day precipitation was DP 3-10 while 

DP 11-20 was the main fraction for 5 days precipitation. Thus, duration time for complete 

precipitation was the factor that should be considered for the high purity inulin preparation. 

Therefore, the composition of inulin was not only effect by type of sovent but also depended 

on the procedure such as times of precipitation and stirring of solution, temperature and 

concentration of the extracts. Phelps (1965) also mentioned that inulin from ethanol 

recrystallization was easier and more solubled than water-recrystallized at the same 

tempearature. 

100

Relative (%) 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

74 

72 

70 

68 

66 

64 

62 

60 

58 

56 

54 

52 

50 

48 

46 

44 

42 

40 

38 

36 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

s 

glu 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

suc 

glu 

suc 

glu 

10 

8 

6 

4 

14 

12 

18 

16 

22 

20 

26 

24 

26 

24 

30 

28 

30 

28 

34 

32 

34 

32 

38 

36 

38 

36 

Degree of Polymerization 

42 

40 

42 

40 

46 

44 

Figure 20 HPAEC-PAD chromatogram of DP distribution profile of inulin precipitated by 

water and different ethanol concentration at 4 o C and 25 o C. 

50% Ethanol;4 o C 

50 

48 

Water; 4 o C 

30% Ethanol; 4 o C 

46 

44 

50 

48 

54 

52 

54 

52 

58 

56 

58 

56 

62 

60 

101

Relative (%) 

16 

14 

12 

10 

8 

6 

4 

2 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

suc 

glu 

4 

s 

glu 

62 

60 

58 

56 

54 

52 

50 

48 

46 

44 

42 

40 

38 

36 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

suc 

glu 

10 

8 

6 

4 

12 

10 

8 

6 

14 

12 

16 

14 

18 

16 

22 

20 

18 

62 

60 

58 

56 

54 

52 

50 

48 

46 

44 

42 

40 

38 

36 

34 

32 

30 

28 

26 

24 

22 

20 

26 

24 

30 

28 

34 

32 

38 

36 

44 

42 

40 


30% Ethanol 25 o C 

48 

46 

70% Ethanol 4 o C 

52 

50 

58 

56 

54 


Figure 20 (Cont.) HPAEC-PAD chromatogram of DP distribution profile of inulin 

62 

60 

precipitated by water and different ethanol concentration at 4 o C and 25 o C. 

66 

64 

102 

64

Relative (%) 

16 

14 

12 

10 

8 

6 

4 

2 

0 

glu 

suc 

6 

4 

8 

10 

12 

14 

16 

18 

20 

22 

24 

28 

26 

Figure 20 (Cont.) HPAEC-PAD chromatogram of DP distribution profile of inulin 

30 


32 

34 

36 


38 

40 


42 

44 

46 

48 

50 

52 

54 

56 

58 

60 

103

Relative (%) 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

glu 

glu 

glu 

suc 

4 

suc 

suc 

6 

4 

8 

4 

10 

6 

6 

12 

8 

14 

8 

16 

10 

18 

10 

12 

Water; 4 o C 

Figure 21 HPAEC-PAD chromatogram of DP distribution profile of inulin in supernatant 

20 

12 


22 

14 

24 

14 

16 

26 

28 

16 

18 


30 

20 

32 

18 

34 

36 

38 

40 


20 

22 

24 


22 

24 

26 

28 

104 

26 

30

Relative (%) 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

14 

12 

10 

8 

6 

4 

2 

0 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

glu 

glu 

glu 

suc 

suc 

suc 

4 

4 

4 

6 

6 

8 

8 

6 

10 

10 

12 

8 

14 

12 

16 

14 

10 

18 

16 


Figure 21 (Cont.) HPAEC-PAD chromatogram of DP distribution profile of inulin in 

20 

12 

18 

22 

20 

14 

24 

supernatant precipitated by water and different ethanol concentration at 4 o C and 

25 o C. 

22 

26 

24 

16 

28 

26 


30 

18 

28 

32 

20 

22 

24 

30% Ethanol; 25 

o 

34 

30 

36 

38 

40 

42 

44 


32 

34 

36 

38 

40 

26 

46 

42 

105

Relative (%) 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

glu 

suc 

4 

6 

Figure 21 (Cont.) HPAEC-PAD chromatogram of DP distribution profile of inulin in 

supernatant precipitated by water and different ethanol concentration at 4 o C and 

25 o C. 

7. Physicochemical Properties of Inulin Gel and Mixed Gel 

Inulin has been used as fat replacer in food that contain starch but little is know about 

the interaction of starch and inulin. Interactions of inulin with other food component need to 

be investigated to determine types of interaction, functional properties and characteristics for 

useful application. In the mixed gel studies, inulin was mixed with hylon VII (high amylose 

corn starch), amioca (high amylopectin corn starch) and normal corn starch. The amylose 

content, as determined by potentiometric iodine method to form blue color substance are: 

normal corn starch was 27%, and for hylon VII starch was 71% (Richardson et al., 2000). 

The amylopectin content of amioca was 98%. The physical characteristics of inulin 

Raftiline ® HP and inulin JAT were described as following. 

Raftiline ® HP was extracted from chicory roots and spray dried. The purity is > 

99.5% and the average degree of polymerization is > 25. The relative composition which 

analyzed by HPAEC-PAD (as the prior method) had no sugar, DP 3-10 3.68% and DP > 10 

96.32%. Raftiline ® HP was white granulated particle and free flowing as sugar. The moisture 

content was 4.66%. 

8 

10 

12 

14 

16 

18 

20 

22 

24 

26 


28 

30 


32 

34 

36 

38 

40 

42 

44 

106

Inulin JAT was extracted from Jerusalem artichoke, precipitate by 70% final ethanol 

concentration and then separated by centrifugation. Inulin JAT was freeze dried look like 

flour and yellowish color. The relative composition which analyzed by HPAEC-PAD was 

sugar 7%, DP3-10 34.26 % and DP > 10 59.51%. The moisture content was 8.25%. 

7.1 Water solubility of inulin 

Inulin was hygroscopic which clumped when dispersed into water. Factors 

affecting inulin solubility which were controlled during the experiment were temperature, 

amount of water, inulin particle size, speed of mixing, size of stir bar, size of containers to 

control rate of water evaporation, and time for seeing undisslove particles. Water was 

preheated at each specific temperature of experiment before adding inulin to minimize 

thermal lag (Kim and Wang, 2001). The temperature was monitored with thermometer and 

controlled throughout the experiment including the filtration of excess inulin in order to had 

the constant temperature. Dissolve process was related to mass transfer which was controlled 

by using constant speed of mixing in a constant beaker size to avoid variation of 

solubilization rate of mixing (Kim and Wang, 2001). Thus, solubilization of inulin was 

influenced mainly by temperature. However, at the high temperature water evaporated 

rapidly. 

Solubility of inulin increased when temperature elevated (Fig. 22). Inulin was 

hardly soluble in cold water. At 20 o C, inulin was almost insoluble. Solubility of Raftiline HP 

was only 0.3% (w/v) at 20 o C and increased to 46.14% at 90 o C. Inulin JAT, solubility was 

only 0.28% (w/v) at 20 o C and increased to 26.03% at 90 o C. The solubility process of inulin 

was a pseudo first-order reaction and dissolution of inulin was completed within 3 to 4 min of 

heating. At the same time, heating for long time especially at temperature higher than 80 o C 

hydrolyzed inulin was occurred (Kim and Wang, 2001). 

The solution of inulin HP was clear, yellowish, and had low viscosity at the high 

concentration, whereas, inulin JAT solution was more turbid, yellowish and thick solution 

than inulin HP. The Inulin JAT solution was viscous at high concentration at the same 

temperature. Inulin HP exhibited higher solubility than inulin JAT. Although, Phelp (1965) 

said that inulin from ethanol recrystallization was easily and more soluble than waterrecrystallized 

at the same temperature. Solubility might depend upon the purity of inulin and 

physical characteristics of solution. Inulin HP was spray-dried product, fine particle like icing 

107

sugar and flowbility. Inulin JAT was freeze-dried product, fine particle like starch. These 

properties might provide different surface area for water absorption, especially, at high 

concentration of inulin. Inulin HP easily and better dispersed in solution than inulin JAT, 

which always formed clump. These may cause lower water solubility of inulin JAT at high 

Water solubility (%, w/v) 

60 

50 

40 

30 

20 

10 

0 

0 20 40 60 80 100 

Temperature ( o C) 

concentration and high temperature than inulin HP. 

Figure 22 Effect of temperature on solubility of commercial inulin Raftiline HP (inulin HP) 

and inulin from Jerusalem artichoke (inulin JAT). 

7.2 Effect of inulin concentration on gel formation 

Inulin HP 

inulin JAT 

Inulin gel formation could be induced by shear and heat. For shear induced gel 

formation, inulin gel with high shearing (5,000 rpm) used lower amount of inulin to form gel. 

And resulted in smoother texture than low shearing (250 rpm) gel formation. In addition, gel 

from high shear had higher gel strength at the same condition. Thermally induced gel showed 

gel hardness than shear induced gel at the same concentration (Kim et al., 2001). 

In this experiment, inulin was dissolved at 80 o C for 5 min with stirring at 500 

rpm by RVA. Inulin JAT showed viscous solution at high concentration and did not form gel 

even at 25% w/w concentration at low temperature (4 o C) for 48 h. This might due to that 

inulin JAT contained sugar and high content of low DP (DP < 10) when compared with inulin 

HP. Kim et al. (2001) discussed that reducing sugar and low DP are non-gel forming 

components. Viscosity of Inulin HP gradually increased with increasing concentration. At 

high concentration it formed discrete particle gels. 

108

Fig. 23 showed typical sol-gel transition of inulin HP solution. Sol-gel transition 

is often found in carbohydrate gels. Soluble polymers became insoluble to form a semi-solid 

structure (gel) due to association of polymer molecules in solution (sol) (Kim et al., 2001). 

Inulin HP solution 25% (w/w) was clear in hot solution and started to form gel as the 

temperature dropped. Before gel formation, inulin solution (Fig. 23A) showed a whitish or 

yellowish color depending on concentration of inulin and heating temperature (Kim et al., 

2001). As the temperature dropped the inulin solution started to form gel by precipitation of 

dissolved inulin molecules probably through crowding effect (Kim et al., 2001). After setting 

time, inulin solution formed a white gel as in Fig. 23 B. The rate of gel formation depended 

on inulin concentration, heating temperature, particle left in solution and less amount 

hydrophilic solvent added (Kim et al., 2001). 

Kim et al. (2001) indicated that inulin HP solution with low concentrations such 

as 5% (w/v) did not show any gel structure at all heating temperature because the system did 

not have enough particles and/ or molecules density of inulin chain to reach the critical 

crowding effect. 

A B 

Figure 23 Sol-Gel transition of inulin HP solution 25% (w/w) heated at 80 o C for 5 min and 

cooled down at 20 o C for 1 days; A) before cooling; B) after cooling . 

This indicated that there must be a critical inulin concentration for the formation of 

gel structure. Volume gel index (VGI) was used to determine the degree of gel formation of 

inulin. If there were no formed gel, VGI would be 0 or not measurement and increased as 

109

more for gel formation (Table 43). Fig. 24 showed that inulin HP solution at 15% (w/w) after 

cooled down at 20 o C for 1 days formed gel with water left on the surface of gel. The liquid 

portion decreased as inulin concentration increased. 

In this experiment, rate of gel formation increased as concentration of inulin 

increased. Inulin HP 15% (w/w) solution started to turbid in 1 h. Phase separation between 

water and gel occurred in 6 h. Inulin HP 18% (w/w) solution started to turbid in 1 h and had 

phase separation in 3 h. Inulin HP 20% (w/w) exhibited phase separate within 2 h. Inulin HP 

22% (w/w) formed gel within 2 h and inulin HP 25% (w/w) formed gel within 15 min. 

As concentration increased, VGI increased gradually and finally reached 100% 

(Table 43). For example, VGI at 15% (w/w) was 69.2 + 3.9 and increased to 97.1 + 0.7 at the 

concentration of 20%(w/w). By increasing the concentration to 22 and 25% (w/w), the 

solution formed 100% gel. For inulin HP gel preparation, heated at 80 o C for 5 min with 

stirring at 500 rpm, the critical concentration for inulin gel formation was 22% (w/w). The 

critical concentration for inulin HP gel formation of Kim et al. (2001), which heated at 80 o C 

for 5 min with stirring at 500 rpm was 20% (w/v). VGI or ability of gel formation was a 

function of heating temperature, inulin concentration, pH and solvent added. Also, minimal 

inulin concentration required for gel formation increased with increasing heating temperature 

due to hydrolysis of inulin to low DP 

A) B) 20% C) D) 

Figure 24 Gel formation of inulin HP solution at different concentration (% w/v) heated at 

80 o C for 5 min and cooled down at 20 o C for 1 days. A) 15%, B) 20%, C) 21% and 

D)22%. 

110

The texture of inulin HP gel at shear rate 500 rpm was creamy, fat-like gel 

similar to butter or yogurt depending on concentration. Gel strength was a strong function to 

inulin concentration. For example, the hardness of 22% (w/w) inulin HP gel was 0.89 + 0.14 

N at and 2.46 + 0.10 N at 25% (w/w). Gel firmness increased as inulin concentration 

increased (Table 43). 

Kim et al. (2001) mentioned gel strength was a strong function of inulin 

concentration and also depended on the method of gel preparation. Gel hardness decreased 

with increased in temperature because inulin was hydrolysis to low DP and simple sugar. The 

method of gel preparation by thermally induced gel created stronger gel than shear induced 

gel. Shear induced gel formed gel with hydrogen bond and van der Waals interaction among 

disperses particles (aggregates of molecules). But thermally induced gel formed the network 

structure through entanglement of molecules into smaller particles as compared to that of 

shear gel (Kim et al., 2001). 

Table 43 Degree of gel formation and gel strength of inulin HP at different concentration. 

Inulin concentrations 

(%,w/w) 

Volumetric gel index 

(%) 

Gel strength 

(N) a 

Firmness 

(N/s) a 

15 69.2 + 3.9 N/A N/A 

18 94.7 + 0.60 N/A N/A 

20 97.1 + 0.70 N/A N/A 

22 100 0.89 + 0.10 0.04 + 0.01 

25 100 2.46 + 0.14 0.12 + 0.01 

a gel strength and firmness were measured only for samples with 100 % VGI 

N/A = not measured because the product did not show 100% VGI 

7.3 Effect of inulin on pasting properties of starch 

This experiment observed the effect of inulin on gelatinization and functional 

properties of starch. The mixed gel was prepared by RVA which provide information about 

pasting temperature and viscosity of gel. The effect of inulin HP and inulin JAT on pasting 

properties were shown in Table 44 - 45 and Figure 25-27. 

111

Table 44 Effect of inulin HP on pasting temperature, peak viscosity and final viscosity of gel 

by Rapid Visco-Analyser. 

Sample Pasting Temperature Peak Viscosity Final Viscosity 

(%, w/w) ( o C) (Cp) (Cp) 

Hylon, 20% 92.5 + 0.0 486.6 + 29.9 302.2 + 25.4 

HP: hylon (1:10), 20% 92.3 + 0.5 250.2 + 13.0 164.9 + 16.1 

HP: hylon (1:5), 20% 92.1 + 0.0 64.4 + 6.5 27.6 + 6.4 

Amioca, 15% 71.6 + 0.2 1116.3 + 53.3 512.7 + 45.2 

HP: amioca (1:10), 15% 71.5 + 0.1 1005.7 + 61.4 475.9 + 20.1 

HP: amioca (1:5), 15% 71.5 + 0.0 838.0 + 34.0 399.0 + 21.4 

HP: amioca (3:5), 15% 73.2 + 0.1 447.23 + 23.7 218.8 + 32.3 

Corn, 8% 84.1 + 0.0 366.3 + 21.2 268.0 + 16.7 

HP: corn (1:5), 8% 84.5 + 0.0 229.1 + 14.1 169.8 + 14.6 

HP: corn: amioca (1:2:3), 8% 74.3 + 0.0 215.7 + 24.3 124.7 + 24.5 

The temperature at the onset of a rise in viscosity is known as the pasting 

temperature. The pasting temperature provides an indication of the minimum temperature 

required to cook a given sample. Hylon or high amylose starch had highest gelatinization 

temperature of > 92 o C, and > 84 o C for corn starch, and > 71 o C for amioca or high 

amylopectin starch. Pasting temperature increased as the content of amylose increased. Jane 

et al. (1999) determined pasting temperature of starch by RVA and found that pasting 

temperature of normal corn starch was 82 o C, of high amylopectin starch was 69.5 o C. But for 

hylon it could not be detected by RVA. Pasting properties of starch were rather complex 

which affected by amylose, lipid contents, and by branch chain length distribution of 

amylopectin. Amylopectin contributed to swelling of starch granules and its pasting 

temperature, where as amylose and lipid inhibited the swelling (Tester and Morrison, 1990). 

The amylose-lipid complex in normal starch caused an increase in pasting temperature and 

increase in resistance to shear thinning of starch pastes. High amylose affected solubilization 

and gelation behavior and act as restraint to swelling (Richardson et al., 2000). 

Inulin HP and inulin JAT in a single system did not have pasting temperature nor 

pasting curve as starch. In a mixed system, inulin HP and inulin JAT at ratio of inulin:starch 

1:5 and 1:10 did not effect on the pasting temperature. But at a ratio of 3:5, the pasting 

temperature was slightly raised. The pasting temperature of inulin JAT system was higher 

112

than that of inulin HP system. This might due to inulin JAT had more sugar content than 

inulin HP. 

Table 45 Effect of inulin JAT on pasting temperature, peak viscosity and final viscosity of 

gel by Rapid Visco-Analyser. 

Sample Pasting Temperature Peak Viscosity Final Viscosity 

(%, w/w) ( o C) (Cp) (Cp) 

Hylon, 20% 92.5 + 0.0 486.6 + 29.9 302.2 + 25.4 

JAT: hylon (1:10), 20% 93.0 + 0.9 185.6 + 4.1 133.2 + 3.5 

JAT : hylon (1:5), 20% 92.9 + 0.6 97.4 + 9.8 69.6 + 6.1 

Amioca, 15% 71.6 + 0.2 1116.3 + 53.3 512.7 + 45.2 

JAT: amioca (1:10), 15% 72.3 + 1.6 783.50 + 3.7 429.4 + 7.6 

JAT: amioca (1:5), 15% 72.1 + 0.3 653.6 + 5.6 391.8 + 41.0 

JAT: amioca (3:5), 15% 73.2 + 0.2 429.4 + 7.6 210.8 + 5.6 

Corn, 8% 84.1 + 0.0 366.3 + 21.2 268.0 + 16.7 

JAT: corn (1:5), 8% 85.0 + 0.0 208.0 + 5.3 158.8 + 5.3 

JAT: corn: amioca (1:2:3), 8% 75.01 + 0.0 226.8 + 4.4 149.6 + 6.3 

The peak viscosity occurs at the balance (cross over) point between swelling of 

starch granule causing an increase in viscosity, and rupture and alignment causing its 

decrease. The viscosity of the starch paste increases as the starch granule swell and then 

decreases as the starch granule breakdown. Peak viscosity indicates the water-binding 

capacity of the starch or mixture. It is often correlated with final product quality. Final 

viscosity is the most commonly used parameter to define a particular sample’s quality. It 

indicates the ability of the material to form a viscous paste or gel after cooking and cooling. 

Inulin affected the viscosity of starch-inulin mixed gel. The viscosity of the mixed gel 

decreased as inulin content increased. Inulin might disrupt the gel net work of starch. These 

will be discussed in section 7.5. 

113

Viscosity cP 

Viscosity cP 

600 

450 

300 

150 

0 

600 

450 

300 

150 

0 

0 3 6 9 12 15 

Time mins 

Figure 25 Pasting curves of inulin and inulin-hylon mixed gel; A) inulin HP-hylon mixed gel, 

B) inulin JAT-hylon mixed gel. 

Hylon 

HP : Hylon; 1:10 

HP : Hylon; 1: 5 

0 3 6 9 12 15 

Time mins 

HP 

Hylon 

JAT : Hylon; 1:10 

JAT : Hylon; 1: 5 

JAT 

B) 

A) 

100 

80 

60 

40 

100 

80 

60 

40 

Temp 'C 

Temp 'C 

114

Viscosity cP 

Viscosity cP 

0 

400 

320 

240 

160 

80 

400 

240 

120 

Figure 26 Pasting curves of inulin-corn mixed gel; A) inulin HP-corn mixed gel, B) inulin 

JAT-corn mixed gel. 

0 

Corn 

Corn 

A) 

JAT: corn: amioca 

1:2:3 

HP :corn 1:5 

HP: Corn: amioca 1:2:3 

JAT: corn 1:5 

0 3 6 9 12 15 

Time mins 

B) 

0 3 6 9 12 15 

Time mins 

100 

80 

60 

40 

100 

80 

60 

40 

Temp 'C 

Temp 'C 

115

Viscosity cP 

Viscosity cP 

0 

800 

600 

400 

800 

600 

400 

200 

0 

Figure 27 Pasting curves of inulin-amioca mixed gel; A) inulin HP-amioca mixed gel, B) 

inulin JAT-amioca mixed gel. 

A) 

Amioca 

HP: Amioca 1:10 

HP: amioca 1:5 


0 3 6 9 12 15 

Time mins 

B) 

Amioca 

JAT: amioca 1:10 


JAT: Amioca 3:5 

0 3 6 9 12 15 

Time mins 

100 

80 

60 

40 

100 

80 

60 

40 

Temp 'C 

Temp 'C 

116

viscosity reduction (%) 

20 

0 

-20 

-40 

-60 

-80 

-100 

 

 

 

 

 

 

 

HP-hylon; 1:10 

 

HP-amioca; 1:10 

 

 

 

 

 

 

 

HP-hylon; 1:5 

HP-amioca; 1:5 

HP-corn 1:5 

Figure 28 Effect of inulin on viscosity reduction of inulin-starch mixed gel; A) inulin HP- 

starch mixed gel, B) inulin JAT-starch mixed gel. 

 

A) 

 

0 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Inulin-starch mixed gel showed a decreased viscosity. By calculating viscosity 

reduction from single starch gel, there was more viscosity reduction as inulin content 

increased (Fig. 28). Inulin had more effect high amylose (Hylon) starch than high 

amylopectin starch (Amioca). 

In this study, hylon starch gel was prepared by RVA at 95 o C for 8 min. 

Richardson et al. (2000) suggested that the high temperature (>90 o C) and pressure such as in 

jet cooking or longer heating time were often required for complete solubilization or 

gelatinization. Also, Jane et al. (1999) mentioned that high amylose starch did not completely 

gelatinization under the RVA cooking conditions at temperature 95 o C for 5 min and then 

cooled to 50 o C. 

Fig. 29A showed birefringence of hylon starch granules. The starch granules 

viewed under crossed polar in a light microscope show a characteristic “Maltese cross” 

pattern indicating molecular orientation within the granule. The granules exhibited positive 

birefringence, indicating that the molecular orientation was radial (Morris, 1998). 

Gelatinization resulted in loss of molecular orientation and a breakdown of the crystalline 

structure. Swelling of the granules leaded to solubilization of the amylose (Morris, 1998). 

Fig. 29B demonstrated all hylon starch had lost of birefringence due to gelatinization after 

cooking. This result indicated that hylon can be gelatinized at 95 o C for 8 min with agitate at 

viscosity reduction (%) 

20 

-20 

-40 

-60 

-80 

-100 

JAT-hylon; 1:10 

JAT-amioca; 1:10 

JAT-hylon; 1:5 

JAT-amioca; 1:5 

JAT-corn; 1:5 

117 

B)

160 rpm under the RVA condition. However, all gelatinized starch granules did not 

completely solubilized. Some granules were swell and some were breakdown. 

(A) (B) 

Figure 29 Photomicrograps of Hylon starch granules: A) Cross polarized light raw starch 

granule (Magnification x 10); B) bright field illumination (Magnification x 5) of 

cooked starch at 95 o C. 

Lewis (1988) mentioned that starch gel could be formed by cooling the mixtures 

at various stages of cooking. Early on the cooking cycle, the starch grains were relatively 

compact and only a small amount of free amylose was available to from gel and this resulted 

in a weak, brittle gel. At the point of maximum viscosity in the cooking cycle, the gel formed 

upon cooling had very swollen but intact starch granule with a fair amount of amylose to act 

as cement. This resulted in a reasonable firm gel. Prolonged cooking caused the breakdown 

of the starch granules and resulting in a soft and elastic gel. 

7.4 Gel strength of inulin and mixed gel 

In the force-distance or force-time curves from texture analyzer, there was an 

initial rapid rise in force over a short distance as the punch moves onto the sample. During 

this stage the sample is deforming under the applied force; there is no puncturing of the tissue 

(Mohsenin, 1986). This stage ends abruptly when the punch begins to penetrate into the food, 

which caused sudden change in slope called the “yield point” or “bioyield point”. The initail 

deforamtion stage is not of great concern. The bioyield point marks the instant when the 

punch begins to penetrate into the food, causing irreversible crushing or flow of the 

underlying tissue and is the point of greatest interest. After bioyield point, the direction of 

118

force change during penetration of the punch into the food separates the puncture curves into 

three basic types; A) the force continuous to increase, B) the force is approximately constant, 

and C) the force decrease (Bourne, 2002). Mohsenin (1986) defined bioyield as a decrease 

or no change in force with increasing deformation occurring before rupture. 

Stiffness (modulus) or rigidity is the resistance to deformation, indicated by the 

slope of the initial force-deformation curve. The ratio of stress to strain of the curve may be 

referred to as modulus of elasticity or Young’s modulus (Mohsenin, 1986). The term of 

Young’s modulus of elasticity may be substituted with modulus of deformability in food 

materials (Bourne, 2002). Gel strength is measured by a maximum force reading. Area is a 

represent of toughness or work, which required a fracturing of the sample. 

Initial peak or bioyield (FYield and DYield), maximum force (Fmax), total area 

(energy), and gradient (slope) in Table 46 were extracted from the loading portion of the 

force-time curves (Fig. 30). 

Inulin HP gel property depended on inulin concentration and method of gel 

preparation as previous discussion. Gel strength, firmness, yield point and modulus of 25% 

(w/w) inulin was higher than 22% (w/w) inulin HP gel (Table 46). According to Zemeri and 

Kokini (2003b) who evaluated inulin gel stored for 24 h by steady shear and found that inulin 

gel 30% and 40% had yield stress behavior but had no yield in 10% and 20% inulin 

concentration gel. Zemeri and Kokini (2003b) result was different from this studied might 

due to the different method for gel preparation. Zemeri and Kokini (2003b) prepared gel at 

shearing speed of 350 rpm and heated at 9 o C 0 for 30 min which caused hydrolyzed inulin by 

heat (Kim and Wang, 2001). 

The effect of inulin on textural and properties of gel was demonstrated in Table 

46 and Fig. 30. Fig 30A, after trigger force of 0.01N was attained the probe then proceeded 

to penetrate into the gel to a depth of 10 mm. During this penetration the force dropped and 

then increased, at the point where the gel break. The peak force (i.e. the rupture point of the 

gel) was recorded as yield point or rupture force (or rupture strength). Rupture point 

corresponded to a failure in the macrostructure of the specimen. The rupture point might 

occur at any point on the force-deformation curves beyond the yield point. The rupture force 

of inulin HP gel was the highest. Dyield (breaking strain) and Fyield (breaking stress) of HP gel 

increased with increasing concentration (Table 46). At high concentration, gel became harder 

119

and tougher. Yoshimura et al. (1998) suggested that the breaking stress of polymer gel 

always increased with increasing concentration of polymer, while whether the breaking strain 

increased or decreased might depend on type and concentration of a polymer. 

Inulin HP gel structure was shown in Fig. 31A and 32A which had uniform size 

and fine particles. These structures provided a firm gel. When inulin HP was added in inulinstarch 

mixed system, it caused a decrease in rupture force (Table 46). This might due to 

interfering of inulin on structure of starch gel. 

The rupture force of hylon gel structure was lower than inulin HP gel and 

decreased as inulin was added. This might explain by photomicrograph in Fig. 31B, E and 

33A that hylon gel had non-uniform and large particle as compared for inulin HP gel. This 

hylon gel structure provided a low firmness gel structure when compared with inulin HP gel. 

For brittle material rupture might occur in the early portion of the curve. For 

tough material rupture might take place (Mohsenin, 1986). The distance that gel was 

penetrated before the yield point (Dyield) occurs gave and indication of the gel’s elasticity i.e. a 

short distance indicated a brittle gel where as a long distance indicated a more elastic gel. 

Inulin HP gel was brittle than hylon gel and corn gel, respectively, Inulin added in inulinstarch 

mixed system caused an increase in brittleness (Table 46). When comparing the 

amylose content of hylon which higher than corn starch, the increasing in modulus and 

rupture force of the inulin-hylon starch mixed gel and inulin-corn starch mixed gel appeared 

to be related to the increase in amylose concentration. The starch gel was more rigid and 

stronger as amylose content increased (Case et al., 1998). 

In the experiments Fig. 30A-E, inulin HP, hylon, inulin-hylon, corn and inulincorn 

gel shown initial rapid rise or yields point. While Amioca, inulin-amioca and inulincorn-amioca 

gel did not have yield point Fig. 30F-H. This type curve is found with some 

starch pastes, which behaves essentially as a viscous liquid, and is unsuited to the puncture 

test because no meaningful results (Bourne, 2002). Puncture curve beyond the yield point 

represents the force required to penetrate into the food. The force change after yield point of 

inulin HP, hylon, inulin-hylon gel was continuous increase while the force of corn and inulincorn 

gel was approximately constant (Fig, 30D). The continuous change in slope 

approximately zero and had followed multiple peaks which denote fracture events. 

120

Force (N) 

3.000 

2.000 

1.000 

0.000 

-1.000 

0.0 

-2.000 

5.0 10.0 15.0 20.0 25.0 

Time (sec.) 

-3.000 

-4.000 

A 

C 

Inulin HP 

F yield 

JAT;hylon 1:10 

JAT;hylon 1:5 

JAT: corn 1:5 

JAT: corn : amioca 

1: 2: 3 

Force (N) 

1.400 

0.000 

-0.200 0.0 5.0 10.0 15.0 20.0 

-0.400 

-0.600 

Figure 30 Force –time curves of inulin-starch mixed gel using 5-mm diameter flat-faced 

1.200 

1.000 

0.800 

0.600 

0.400 

0.200 

Force (N) 

0.600 

0.500 

0.400 

0.300 

0.200 

0.100 

-0.200 

E 

-0.100 

-0.150 F 




Hylon 

Time (sec.) 

HP: Hylon 1:10 

HP: Hylon 1:5 

0.000 

-0.1000.0 

5.0 10.0 15.0 20.0 

Time (sec.) 

Force (N) 

0.300 

0.250 

0.200 

0.150 

0.100 

0.050 

G H 

B 

D 

D yield 

Fmax 

0.000 

-0.050 0.0 5.0 10.0 15.0 20.0 

cylinder probe loading at 0.5 mm/s for 10 mm depth. A) Inulin HP, B) Hylon and 

HP hylon, C) JAT : hylon, D) Corn and HP : corn, E) JAT: corn, F) Amioca, G) 

JAT: amioca, H) HP : amioca. 

Corn 

HP: corn 1:5 

Amioca 

Time (sec.) 

121 

HP: corn: amioca 

1: 2: 3 


HP: amioca 1:10

Table 46 Textural properties of inulin HP and inulin-starch mixed gel as calculated from force-time curve. 

Sample FYield 

DYield 

Young Modulus 

(rupture force) (brittleness) (stiffness) (gel strength) (firmness) (toughness) 

(%, w/w) (N) (mm) N/mm 2 

(N) (N/s) Ns 

Inulin HP 25% 1.54 + 0.07 1.12 + 0.10 1.06 + 0.14 2.46 + 0.14 0.123 + 0.008 38.67 + 2.45 

Inulin HP 22% 0.51 + 0.05 0.90 + 0.13 0.44 + 0.10 0.89 + 0.10 0.043 + 0.005 13.90 + 1.24 

Hylon, 20% 0.47 + 0.05 1.52 + 0.30 0.24 + 0.05 1.28 + 0.03 0.064 + 0.005 15.13 + 0.34 

HP: hylon (1:10) 0.26 + 0.05 1.22 + 0.21 0.18 + 0.02 0.80 + 0.03 0.039 + 0.004 7.80 + 1.20 

HP: hylon (1:5) 0.13 + 0.01 1.38 + 0.19 0.07 + 0.01 0.48 + 0.03 0.023 + 0.001 4.83 + 0.19 

JAT: hylon (1:10) 0.26 + 0.02 0.99 + 0.18 0.14 + 0.05 0.51 + 0.28 0.030 + 0.002 7.26 + 0.52 

JAT: hylon (1:5) 0.20 + 0.02 0.96 + 0.35 0.11 + 0.04 0.43 + 0.18 0.022 + 0.003 5.02 + 0.23 

Amioca, 15% N/A N/A 0.015 + 0.003 0.19 + 0.02 0.009 + 0.002 1.90 + 0.29 

HP: amioca (1:10) N/A N/A 0.002 + 0.001 0.04 + 0.07 0.009 + 0.001 1.94 + 0.15 

HP: amioca (1:5) N/A N/A 0.014 + 0.002 0.18 + 0.02 0.002 + 0.00 0.41 + 0.06 

HP: amioca (3:5) N/A N/A 0.003 + 0.000 0.05 + 0.01 0.002 + 0.00 0.60 + 0.05 

JAT: amioca (1:10) N/A N/A 0.004 + 0.001 0.08 + 0.02 0.004 + 0.001 0.73 + 0.30 

JAT: amioca (1:5) N/A N/A 0.005 + 0.000 0.09 + 0.01 0.005 + 0.001 1.03 + 0.08 

orn, 8% 0.34 + 0.02 3.58 + 0.07 0.08 + 0.02 0.40 + 0.03 0.019 + 0.002 5.31 + 0.39 

HP: corn (1:5) 0.16 + 0.01 2.78 + 0.07 0.04 + 0.00 0.14 + 0.01 0.006 + 0.001 2.47 + 0.17 

HP: corn: amioca (1:2:3) N/A N/A 0.003 + 0.00 0.04 + 0.00 0.001 + 0.00 0.53 + 0.02 

JAT: corn (1:5) 0.08 + 0.01 1.00 + 0.23 0.02 + 0.00 0.10 + 0.01 0.003 + 0.001 1.32 + 0.16 

N/A: Not available because the samples did not show yield point. 

FMa x 

Gradient 

Area 

117 

122

The breaking strain, breaking stress and elastic modulus of inulin-starch mixed 

gel decreased as increasing inulin content. Mixed gel with high content of inulin became soft 

and brittle gel. Inulin could decreased gel strength, firmness, yield point and modulus of gel. 

Inulin increased gel brittle because Dyield decrease. There was not a synergy between the 

combined components, when the functionality measured as that parameter. Inulin might 

disrupt or decrease continuity the network of starch gel. These arguments were supported by 

structure under microscope presented later. 

7.5 Gel structure of inulin and inulin-starch mixed gel 

The microstructure of gel was studied by SEM and light microscope (Fig. 31- 

34). The network of inulin gel was produced from clumps of particles joined together (Fig. 

31A, 32A). The surface of clumps or gel particles was wrinkle or split. The particle was oval 

shape and rather uniform approximately 2-5 nm in size under preparation at 80 o C with 

shearing speed 500 rpm. The particle size was smaller than Kim et al. (2001) which prepared 

gel at 80-90 o C with stirring at 150 rpm and obtained 2.31 µm particle size. These particles 

packed into larger clusters forming the network (Figure 32A- B). This basic microstructure 

was similar to typical gels of whey protein (Aguilera and Kinsella, 1991). 

Hylon or high amylose gel developed as a mixture of continuous and dispersed 

phased (Figure 31B, 33A, 34A). The swollen hylon granules had smooth surface, round 

shape and varied in particle size. The amylose performed a continuos network will swollen 

starch granules as dispersed phased. The starch granules remained embedded in an amylose 

matrix. Starch gel was a system where the dispersed inclusions and the continuous matrix 

both contribute to the overall properties of gel. During cooking starch granules swelled and 

amylose was released from the granules; on cooling the amylose set into a gel network 

(Lewis, 1998). Amylose could be leached from granules without destroying granule 

crystallinity. Solubilization of a sufficient quantity of amylose was an essential requirement 

for the starch gelation. Swollen granules reinforced amylose gel and postulated amyloseamylopectin 

binding of granules into a network (Morris, 1998). Under light microscope, 

inulin-hylon gel stained with aqueous iodine showed distinctly larger hylon granule in dark 

purple and inulin granule in clear and smaller size (Fig. 34B). This indicated that inulin and 

hylon exhibited phase separation gel type. 

123

The SEM demonstrated amylose network, hylon granules and inulin granules 

(Fig. 34A). These structures might indicate that both component probably gelled 

independent. 

Fig. 31C-D, F-H demonstrated amioca or high amylopectin starch gel, normal 

corn starch gel, inulin-amioca (3:5) starch gel, inulin-corn starch (1:5) gel, and inulin-amiocacorn 

starch gel showed continuous network with out any particle phase. However, the 

structure of amioca gel (Fig. 31C) was more uniform and smoother than inulin-amioca (Fig. 

31F) which had rough surface gel. When comparing corn gel (Fig. 31D), inulin-corn 1:5 gel 

(Fig. 31G), and inulin-corn-amioca 1:2:3 (Fig. 31H), the corn gel had continuous network 

than those of mixed gel. Inulin-corn mixed gel showd multiplesmall sheet-like which overlap 

and stacking to form gel structure. Inulin added might disrupt the continuous network of 

single can gel structure. From the photomicrogrph, the texture of corn gel might expect to be 

stiffer and stronger than inulin-corn mixed gel. The stiffness, rupture force and gel strength 

from texture analyzer confirmed that corn gel was more stiffer and stronger than inulin-corn 

mixed gel as seen in Table 46. 

124

A) B) 

C) D) 

E) F) 

G) H) 

Figure 31 Scanning electron microscopy of inulin HP and inulin HP-starch mixed gel 

(Magnification x 3000); A) inulin, B) hylon, C) amioca, D) corn, E) inulin-hylon 

(1:5), F) inulin-amioca (3:5), G) inulin-corn (1:5), H) inulin-corn-amioca (1:2:3). 

125

(A) (B) 

Figure 32 Photomicrograph of inulin HP gel; A) scanning electron microscopy 

(Magnification x 1000), B) light microscope of inulin gel stained with aqueous 

iodine (Magnification x 32). 

(A) (B) 

Figure 33 Photomicrograph of hylon gel; A) scanning electron microscopy (Magnification x 

A 

1000), B) light microscope of hylon gel (Magnification x 5). 

H 

I 

(A) (B) 

Figure 34 Photomicrograph of inulin HP-hylon 1:5 gel; A) scanning electron microscopy 

126 

(Magnification x 1000), B) light microscope of inulin-hylon gel stained with 

aqueous iodine (Magnification x 10). A: amylose network, H: hylon granule and I: 

inulin granule. 

H 

I

7.6 Rheological properties of inulin gel and inulin-starch mixed gel 

7.6.1 Viscosity of inulin HP solution in constant rate 

The steady shear (constant angular viscosity) measurement was large 

deformation of material. Viscoelastic fluids exhibit normal stresses and measurements them 

provide one way of elastic characterization. 

Inulin HP solution had low viscosity at high temperature. When it was 

cooled down with decreasing temperature the solution was more viscous and gel. Fig. 35 

illustrated apparent viscosity decreased with increasing shear rate which indicated shearthinning 

properties (Steffe, 1996a). This result was similar to Zemeri and Kokoni (2003b) 

exhibited inulin gel (30% and 40%) which stored for 24 h before analysis by steady shear 

exist yield stress behavior. At low temperature, 20 o C and 30 o C, inulin solution showed higher 

viscosity. Increase inulin concentration resulted in increase viscosity and gel formation (Fig. 

36). Inulin HP solution at 25% (w/w) clearly showed sol-gel phase transition at approximate 

40 o C. 

The gel point are an infinite steady-shear viscosity, however, because 

continuous shearing affects gel formation from viscosity measurement is not possible in the 

close vicinity of the gel point. The small deformation as dynamic technique can obtained 

actual gel point (Silva and Rao, 1991). Then inulin HP solution was evaluated viscoelastic 

behavior under oscillatory rheological analysis. 

127

Figure 35 Steady shear characterized apparent viscosity of inulin HP 25% (w/w) solution at 

Apparent viscosity (Pa s) 


0.400 

0.350 

0.300 

0.250 

0.200 

0.150 

0.100 

0.050 

- 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

different temperature as function of shear rate. 


0.050 

0.045 

0.040 

0.035 

0.030 

0.025 

0.020 

0.015 

0.010 

0.005 

70oC 50oC 30oC 20oC 


14 19 26 35 47 64 87 118 160 217 251 297 

shear rate (1/s) 

15%HP 18%HP 20%HP 22%HP 25%HP 

0.000 

70 65 62 58 54 51 47 43 39 36 32 29 27 25 

Temperature ( oC) 70 65 62 58 54 51 47 43 39 36 32 29 27 25 


Figure 36 Steady shear characterized apparent viscosity of inulin HP solution at different 

concentration as function of decreasing a (cool down) temperature. 

0.140 

0.120 

0.100 

0.080 

0.060 

0.040 

0.020 

- 

14 19 26 35 47 64 87 118 160 217 251 297 

shear rate (1/s) 

128

For many polymer systems, gelation, began from a sol state, which often 

below the strain oscillatory resolution. Thus the gel point or networks formation, indicated by 

the point when storage modulaus (G′) increased to a value greater than an experiment noise 

level (Silva and Rao, 1991; Durrani and Donald, 1995). Gel temperature also was determined 

by rapidly rise values of G′ at the temperature axis. Temperature sweep was performed from 

70 o C to 20 o C at rate 0.5 o C/min. Fig.37A show that inulin HP solution (25% w/w) at 1% 

strain value formed gel at 55 o C, which G′ raised rapidly and phase lag (δ) changed from 

viscous to elastic. Since at this point G′ was higher than loss modulus (G′′) which indicted 

that material was in gel state (Chenite et al., 2001). When measured gel point at 0.5% strain 

it was found the inulin HP formed gel at a range 60-65 o C, which was higher than at 1% strain 

(Fig. 37B). This indicated that gel point or gel temperature depended on strain, which 

referred to gel deformation. Gel temperature obtained from steady shear measurement was 

40 o C, which it was 55 o C from the temperaure sweep oscillatory experiment. The gel 

temperature was slightly different. The dynamic test, by oscillatory obtained higher gel point 

temperature because the strain was kept small. Therefore modification of molecular structure 

caused by shear was minimized. 

According to Zemeri and Kokini (2003b) studied inulin HP solution at room 

temperature by dynamic rheological and found that at low concentration (2%) inulin HP was 

in typical non gelling/ liquid-like system. At 5% and 10% concentration inulin HP exhibited 

dilute solution system. At 20% gel was formed and had syneresis. At high concentration 

(30%) inulin gel structures had no entanglement, with particles sliding one on top of the other. 

At 40% inulin HP gel exhibited the typical highly crystalline polymer and strong gel 

129

G', G'' (Pa) 

G', G'' (Pa) 

100,000 

10,000 

1,000 

100 

10 

1,000,000 

100,000 

10,000 

1,000 

100 

10 

1 

20 25 30 35 40 45 50 55 60 65 70 

B) 

A) 


G' 1% strain 

G'' 1% strain 

Phase 1% strain 

1 

20 25 30 35 40 45 50 55 60 65 70 


G' 0.5% strain 

G'' 0.5% s train 

Figure 37 Temperature sweep demonstrated sol-gel transition on inulin HP 25% (w/w); 

measured at constant frequency at 1 Hz with 1% strain A) and 0.5% strain B). 

1 

130 

100 

Phase () 

10

7.6.2 Rheological properties of hylon and inulin HP-hylon gel 

The important factors governing paste and gel rheology were rheology of 

the matrix (amylose), the rigidity of the filler (granule), and the volume fraction of the filler 

and the filler-matrix interaction. An amylose-amylopectin network was the classical fringed 

micellar gel structure. Amylose molecules were considered to participate on several junction 

zones and deformability was attributed to perturbation of the polymeric linkages between 

junction zones. The amylose formed opaque elastic thermoirreversible gels at concentrations 

>1.5% w/w (Morris, 1998). The behavior of system of two or more polymers was important. 

They interacted with each other, either by stacking together or by separating apart, called 

associative or aggregate effects which leaded to heterogenous gels (Silva and Rao, 1991). 

Amylose gel formation progressed through two stages 1) molecular 

aggregation, by double helix formation and elongation at the tip and 2) lateral association of 

the helical regions (Okechukwu and Rao, 1998). These stages were influenced by molecular 

weight or the degree of polymerization. Aggregation was favored by high DP, where as 

lateral association was favored by low-molecular weight amylose molecule (Okechukwu and 

Rao, 1998). Amylose gel was generally stiff, with values of G′ no variation with frequency. 

The gels were irreversible to temperature below 100 o C and developed full gel strength within 

2-4 hrs. G′ was highly dependent on amylose concentration. 

mixed gel 

7.6.2.1 Modulus change as a function of strain for hylon and inulin HP-hylon 

Strain sweep or amplitude sweep conducted by varying the amplitude 

at a constant frequency, was used to determine the limits of linear viscoelasticity behavior. In 

linear regions rheology properties were not strain or stress dependent and also gel structure 

was not break down. The limit of linear region was considered at the point where G’ was 

decreased. Strain sweep also was used to differentiate weak and strong gel. Strong gel might 

remain in the linear region over greater than weak gel. Rheological, weak gel was relatively 

viscoelastic, had shorter linear elastic regions, and fracture more easily (Steffe, 1996b). Fig. 

38 demonstrated that magnitude of G′ decreased with increasing inulin content and 

temperature. The linear region of hylon 20%(w/w) and inulin HP-hylon (1:10) mixed gel at 

each temperature was quite similar, the strain was not over 0.01 (1%). Linear region of HP: 

hylon; 1:5 at each temperature was different at 20 o C and 30 o C and had wide range of linear 

131

egion when the strain was not over 0.001 (0.1%) strain. But at 50 o C and 70 o C the linear 

region was not clearly seen might because the gel was too soft. The results demonstrated 

hylon and HP: hylon 1:10 gel were stronger than HP: hylon 1:5. It also indicated the inulin 

HP gel weakens than the hylon gel. When considering effect of temperature to G′ found that 

when temperature increased the G′ was decreased except hylon gel which showed strong gel 

at all temperature. Temperature had more effect in mixed gel especially gel with high content 

of inulin HP. This was related to the gelling temperature of inulin HP which inulin Hpmight 

not be complete gel at ~55 o C. The linear viscoelastic region of hylon and HP-hylon gel for 

dynamic experiment was found with the strain value between 0.001 (0.1%) strain. 

7.6.2.2 Modulus change as function of frequency for hylon and inulin HPhylon 

mixed gel 

The frequency sweeped shows how the viscous and elastic behavior of 

material changed with the rate of strain applied. The frequency was increased while the 

amplitude or strain was held constant. The strain applied was 0.001 (0.1%) which was 

obtained from strain sweep experiment in section 7.6.2.1. Fig. 39 showed the frequency 

sweep of gel at different temperature. In all temperature G′ was higher than G′′. Which that 

meant the solution exhibited gel-like behavior over the studies range of frequencies. Based 

on frequency sweep data one could designate “ true gels” are G′ was higher than G′′ 

throughout the frequency range and G′ was almost independent of frequency. The other were 

“weak gel” which G′ moduli was highly dependent on frequency (Silva and Rao, 1991). In 

hylon gel, at all temperature gel performed a plateau modulus and because G′ was higher than 

G′′ and independent of frequency so the sample was classified as strong gel. The typical 

characteristics of highly crytalline polymer in which G′ curve was relatively flat throughout 

the frequency range and G′′ wass considerably less than G′(Okechukwu and Rao, 1998). 

HP-hylon mixed gel at 50 o C and 70 o C performed weak gel because G′ 

and G′′ increased as frequency increased. Inulin HP might not be form gel at these 

temperatures as described in 7.6.1. At low temperature 20 o C and 30 o C inulin HP-hylon 

mixed gel were performed as strong gel. 

132

G' (pa) 

G' (Pa) 

G' (Pa) 

10000 

1000 

100 

10 

1 

A 

0.0001 0.001 0.01 0.1 1 10 

strain (%) 

10000 

1000 

10000 

1000 

100 

100 

10 

1 

10 

1 

C 

B 

0.0001 0.001 0.01 0.1 1 10 

strain (%) 

Figure 38 Dynamic rheological data for storage modulus in strain sweep at different 

temperature; A)20% (w/w) hylon, B) inulin HP: hylon; 1:10, and C) inulin HP: 

hylon; 1:5 at 1 Hz frequency. 

70 

50 

30 

20 

G'70 

G'50 

G'30 

G'20 

0.0001 0.001 0.01 0.1 1 10 

strain (%) 

G'70 

G'50 

G' 30 

G'20 

133

G',G'' (Pa) 

G',G'' (Pa) 

G',G'' (Pa) 

100000 

10000 

1000 

100 

10 

1 

100000 

10000 

1000 

10000 

1000 

100 

10 

A 

0.01 0.1 1 

Frequency (Hz) 

10 100 

100 

10 

B 

C 

Figure 39 Dynamic rheological data for modulus in frequency sweep at different 

temperature; A) 20% (w/w) hylon, B) inulin HP: hylon; 1:10, and C) inulin HP: 

hylon 1:5 C) at 0.001 (0.1%) strain and 1 Hz frequency. 

G' 20 

G''20 

G' 30 

G''30 

G'50 

G''50 

G'70 

G''70 

G ' 20 

G ''20 

G ' 30 

G ''30 

G '50 

G ''50 

G '70 

G ''70 

1 

0.01 0.1 1 


10 100 

1 

0.01 0.1 Frequency 1 (Hz) 

10 100 

G ' 20 

G ''20 

G ' 30 

G ''30 

G '50 

G ''50 

G '70 

G ''70 

134

7.6.2.3 Modulus change as function of temperature for hylon and inulin HPhylon 

mixed gel 

In the experiment mixed solution dispersion was measured at 0.001 

(0.1%) strain with 1Hz frequency. The temperature was decreased from 70 o C to 20 o C at rate 

0.5 o C /min. Fig. 40 showed storage modulus change as a function of temperature. Hylon 

solution almost gelled immediately at 70 o C, while HP-hylon gelled around at 60 o C. G′ was 

increased as temperature decreased. These indicated that inulin HP affect hylon (amylose) gel 

formation by extended time of gelation and disrupt the amylose gel by decreased the G′ and 

gel strength. 

Tan δ value of these gels were between 0.04-0.1 (Fig. 41) which 

indicated the gel was crystalline (Steffe, 1996b). The value of tan δ increased with increasing 

inulin content. Mixtures with lower inulin HP content were more solid-like than those with 

more content. 

G', G'' (Pa) 

100000 

10000 

1000 

100 

10 

1 

G' hylon 

G'' hylon 

G' HP:hylon; 1:10 

G'' HP: hylon; 1:10 

G' HP: hylon; 1:5 

G'' HP: hylon; 1:5 

- 10 20 30 40 50 60 70 80 


Figure 40 Dynamic rheological data for effect of temperature on modulus at a total polymer 

concentration 20% (w/w) hylon, inulin HP: hylon; 1:10 and inulin HP: hylon 1:5 

with temperature rate 0.5 o C/min at 0.001 (0.1 %) strain and at 1 Hz frequency. 

135

tan δ 

1.00 

0.10 

0.01 

- 10 20 30 40 50 60 70 80 

Figure 41 Dynamic rheological data for effect of temperature on tan δ (phase angel) at a total 

polymer concentration 20% (w/w) hylon gel, inulin HP-hylon; 1:5 and inulin HPhylon; 

1:10 at 0.001 (0.1%) strain and at 1 Hz frequency. 

7.6.3 Rheological properties of corn and inulin HP-corn gel 

Yoshimura et al. (1998) found that G′ and G′′ of corn starch gel 

(concentration 2.1-3.5%) was dependened on concentration where the modulus (G′ and G′′) 

increased with increasing concentration. 


hylon 20 

HP: hylon;1:10 

HP:hylon; 1:5 

7.6.3.1 Modulus change as function of strain for corn and inulin HP-corn gel 

Fig. 42 showed strain sweep of corn and inulin HP-corn gel at 1 Hz 

frequency at different temperature. Corn gel and inulin HP-corn; 1:5 gel performed true gel 

since they had a wide range of linear region than inulin HP-corn-amylopectin; 1:2:3 gel, 

hylon, and inulin HP-hylon gel. The linear region limit of corn gel was not over 0.1 (10%) 

strain, which after this point G′ was decreased due to the structure deformation. Temperature 

had more effect to gel properties because G′ at each temperature was clearly different. Also 

at 50 o C and 70 o C, the liner region was less than at low temperature. The linear limit of inulin 

HP-corn-amioca gel showed weak gel characteristics because G′ was much more less than 

corn and inulin HP-corn and G′ gradually decreased as strain increasing. Inulin HP affected 

corn gel by decreased a G′ at each temperature. Therefor inulin HP-corn-amioca gel, had 

136

different characteristic from corn and HP-corn gel. Inulin HP might not be the only effect on 

the gel but also the amioca. The main effect seemed to be from amioca. 

gel 

7.6.3.2 Modulus change as function of frequency for corn and inulin HP-corn 

The frequency sweep was measured at 0.02 (2%) strain, which was in 

linear region from strain sweep. Fig 43 showed the frequency sweep of gel at different 

temperature. All gel exhibited gel-like behavior because G′ was higher than G′′. At 

frequency < 1 Hz corn and inulin HP-corn gel acted as true gel because the G’ was 

independent with frequency. But when the frequency was higher than 1 Hz the properties 

changed instantly, i.e., G’ depended on frequency. At high frequency 10 Hz, 5 Hz and 3 Hz, 

G′′ of corn, inulin HP-corn and inulin HP-corn-amioca decreased with increasing frequency. 

However G′ did not increase so much as G′′ decreased. This behavior might classified 

rheologically as intermediate between a concentrated polymer solution and weak gel (Morris, 

1983; Clark and Ross-Murphy, 1987). This, indicated that the initial structure has been 

disrupted (Zemeri and Kokini, 2003b). 

When compared gel properties which different inulin content it was 

found that G′ decreased markedly with increasing inulin content. The G′ value of corn gel 

larger than inulin HP-corn and inulin HP-corn-amioca gel (Fig. 43). This indicated that inulin 

HP inhibited the formation of three-dimension network of amylose. This corresponded well 

with the observed elastic young modulus from force-deformation curves (Fig. 30D and 30F). 

From this observations it was suggested that inulin did not interact synergistically with 

amylose to promote the formation of an ordered structure. Inulin HP-corn-amioca gel 

exhibited weak gel because G′ and G′′ was strong frequency dependence, i.e., both G′ and G′′ 

increased throughout the frequency range. 

137

G' (Pa) 

G' (Pa) 

G' (Pa) 

10000 

1000 

10000 

1000 

100 

100 

100 

10 

1 

10 

1 

10 

1 

G'70 

G'50 

G' 30 

G' 20 

0.0001 0.001 0.01 0.1 1 10 

Strain (%) 

B) 

0.0001 0.001 0.01 0.1 1 10 

Strain (%) 

C) 

G '70 

G '50 

G '30 

G '20 

0.001 0.01 0.1 

Strain (%) 

1 10 

Figure 42 Dynamic rheological data of storage modulus in strain sweep at different 

temperature of A) 8% (w/w) corn gel, B) inulin HP-corn; 1:5, and C) inulin HP: 

corn: amioca; 1:2:3 C) at 1 Hz frequency. 

G' 70 

G' 50 

G' 30 

G' 20 

138

G', G'' (Pa) 

G', G'' (Pa) 

G', G'' (Pa) 

10000 

1000 

100 

10 

10000 

1000 

100 

1 

0.01 0.1 1 


10 100 

10 

1 

1000 

100 

10 

Figure 43 Dynamic rheological data of modulus in frequency sweep at different temperature 

G' 30 

G'' 30 

G' 50 

G'' 50 

G' 20 

G'' 20 

G' 70 

G'' 70 

0.01 0.1 1 10 100 


1 

0.01 0.1 1 


10 100 

of A) 8% (w/w) corn gel, B) inulin HP-corn; 1:5, and C) inulin HP: corn: amioca; 

1:2:3 at 0.02 (2%) strain. 

B 

A 

G' 20 

G'' 20 

G' 30 

G'' 30 

G' 50 

G'' 50 

C 

G' 50 

G'' 50 

G' 20 

G'' 20 

G' 70 

G' 30 

G'' 30 

G'' 70 

139

G' (Pa) 

10000 

1000 

100 

10 

G' HP: corn: Amioca; 1:2:3 

G' Corn 

G' HP: corn; 1:5 

G" HP: corn: Amioca; 1:2:3 

G" Corn 

G'' HP: corn 1:5 

1 

0 10 20 30 40 

Tempearature ( 

50 60 70 80 

o C) 

Figure 44 Dynamic rheological data for effect of temperature on modulus at a total polymer 

tan tan δ 

1 

0.1 

0.01 

concentration 8% (w/w) corn gel, inulin HP-corn; and inulin HP: corn: amioca; 

1:2:3 at 0.02 (2%) strain and at 1 Hz frequency. 

HP: corn: amioca; 1:2:3 

HP: corn; 1:5 

Corn 

0 10 20 30 40 

Temperature ( 

50 60 70 80 

o C) 


polymer concentration 8% (w/w) corn gel, inulin HP-corn; and inulin HP: corn: 

amioca; 1:2:3 at 0.02 (2%) strain and at 1 Hz frequency. 

140

corn gel 

7.6.3.3 Modulus changes as function of temperature for corn and inulin HP- 

Fig. 44 showed modulus changes as a function of temperature under 

0.02 (2%) strain and 1 Hz frequency. Corn gel had higher G′ than inulin HP-corn gel and 

inulin HP-corn-amioca gel. As temperature decreased G′ was gradually increased which 

indicated the solution dispersion formed gel with time and temperature dependent. While G′ 

of inulin HP-corn-amioca stayed almost constant throughout the experiment, which indicated 

that inulin HP-corn-amioca needed longer time to form gel. The value of tan δ of the corn gel 

and the mixed gel was between 0.2-0.002, which decreased as temperature decreasing (Fig. 

45). At temperature higher than 57 o C, corn gel and inulin HP-corn gel had similar tan δ value 

and rapidly decreased. At lower than 57 o C, corn gel had lower tan δ than inulin HP-corn gel 

and gradually decreased. This suggested that inulin HP-corn started to gel at this temperature, 

which was close to inulin HP gel temperature. The tan δ of inulin HP-corn-amioca gel was 

0.2 and stayed almost plateaus at every temperature which indicated an occurrence of 

amorphous polymer or soft gel (Steffe, 1996b). 

7.6.4 Rheological properties of amioca and inulin HP-amioca gel 

Amylopectin required high concentration (10% and above) and low 

temperatures for gelation where gel strength approached the limiting value. G′ increased 

faster than G′′ and showed a linear dependent on concentration and a decrease influence of 

frequency. Amylopectin gel was thermoreversible at temperature below 100 o C (Durrani and 

Donald, 1995). 

Amioca (8%w/w) gel measured in steady shear displayed an upswing in 

apparent viscosity at low shear rates which indicated apparent yield stress (Chamberlain and 

Rao, 1999). Dynamic rheological data was performed at 4% strain showed that G′ was higher 

than G′′ and slopes of moduli were parallel which each other. At 4% strain G′ was found to 

be in the linear viscoelastic region at 20 o C. Therefore amioca gel behaved like a weak gel. 

Zemeri and Kokini (2003b) found apparent viscosity of inulin HP-amioca 

mixed gel decreased with increasing inulin content indicated that inulin acted as diluent to 

141

amioca. Thus inulin did not interact synergistically with amioca (amylopectin) to form a 

three-dimension network. 

amioca gel 

7.6.4.1 Modulus change as a function of strain for amioca and inulin HP- 

Amioca or high amylopectin gel showed low G′ when compared with 

hylon and corn gel. Temperature did not much effect on gel properties because G′ at each 

temperature was almost similar. The linear limit of gel indicated weak gel characteristics 

because G′ was low and G′ gradually decreased as strain increasing especially at high ratio of 

inulin HP (Fig. 46) The strain sweep showed that 0.02 (2%) strain was probably within the 

linear region. Durrani and Donald (1995) found the linear region of 30%(w/w) amylopectin 

gel stored at 4 o C over 43 h was at 1% strain. G′ was not valid at lower strain up to ~0.02%. 

This simply was a consequence of poor instrument sensitivity arising from the generation of a 

low torque (Durrani and Donald, 1995). This characteristics were similar to HP-corn-amioca 

gel. Thus in HP-corn-amioca gel, amioca dominate of effect on the mixed gel properties. 

7.6.4.2 Modulus change as a function of frequency for for amioca and inulin 

HP-amioca gel 

The frequency sweep was measured at 0.02 (2%) strain, which was in 

linear region from strain sweep. Fig 47 showed the frequency sweep of gel at 20 o C. All gel 

exhibited gel-like behavior because G′ was higher than G′′. However amioca and inulin HP- 

amioca exhibited weak gel because G′ and G′′ was increased throughout the frequency range. 

At high frequency, gel exhibited more solid-like due to an increase in G′. Durrani and Donald 

(1995) evaluated amylopectin (30%w/w) gel stored and found that it at 4 o C for 312 h 

exhibited strong gel because its moduli was independent with frequency. The storage 

modulus of the amylopectin gel increased with concentration, storage time and molecular 

weight (Durrani and Donald, 1995). Amylopectin gel was the most elastic component of 

inulin-amylopectin mixed gel (Zemeri and Kokini, 2003b). 

142

G' (Pa) 

100 

10 

1 

A) 

G' 20 

G'30 

G' 50 

G' 70 

0.01 0.1 1 

100 

strain (%) 

G' 20 

G' (Pa) 

10 

B) 

1 

0.01 0.1 

strain (%) 

1 

Figure 46 Dynamic rheological data of storage modulus in strain sweep at different 

temperature of A) 15% (w/w) amioca, and B) inulin HP-amioca; 3:5 at 1 Hz 

frquency. 

G' 30 

G' 50 

G' 70 

143

10000 

G', G'' (Pa) 

1000 

100 

10 

1 

G' HP: amioca; 3:5 

G'' HP: amoica; 3:5 

G' Amioca 

0.1 

G'' Amioca 

0.01 0.1 1 


10 100 

Figure 47 Dynamic rheological data of modulus in frequency sweep at 20 o C of A)15% (w/w) 

amioca, and B) inulin HP-amioca; 3:5 at 0.02 (2%) strain and at 1 Hz frquency. 

7.6.4.3 Modulus changes as a function of temperature for for amioca and 

inulin HP-amioca gel 

Fig. 48 showed modulus changes as a function of temperature under 

0.02 (2%) strain and 1 Hz frequency. G′of all gel stayed almost constant throughout the 

experiment, which might indicate that amioca and inulin HP-amioca mixed gel needed longer 

time to form gel. The gelation of amylopectin was found to be such a slow process that 

monitoring gelation in situ on a rheometer was not feasible, except for solutions of 

particularly high concentration. Even then only data at the early stages of gelation could be 

acquired (Durrani and Donald, 1995). The tan δ value of amioca and inulin HP-amioca gel 

was 0.3-0.4 and 0.5-0.7, respectively (Fig. 49). These results indicated HP-amioca gel was 

softer than amioca gel. 

According to Zemeri and Kokini (2003b), the viscosity of inulin-high 

amylopectin starch mixed gel depended on the total polymer concentration and inulin to high 

amylpectin starch ratio. The viscosity increased with total polymer concentration. Up to 20% 

total concentration, viscosity decreased with increasing inulin content. But at total polymer 

concentration > 30%, which was the critical concentration (c*) of inulin gel, viscosity 

144

increased with increasing inulin content. Thus inulin disrupted the structure of high 

amylopectin at low total polymer concentration, while at high total polymer concentrations 

(above inulin’s c*), the rheological properties of the inulin-amylopectin mixed system were 

dominated by those of inulin (Zemeri and Kokini, 2003b). 

It should be noted that amioca gel was clear and sticky as glue and. 

When inulin was added , stickiness decreased and became more opaque as inulin content 

increased by observation. Thus the properties of gel could reverse as the ratio of polymer 

changes. 

G', G'' (Pa) 

100 

10 

1 

G' Amioca 

G'' Amioca 

G' HP: amioca; 3:5 

G'' HP: amoca; 3:5 

0 10 20 30 40 50 60 70 


Figure 48 Dynamic rheological data of effect of temperature on modulus of A)15% (w/w) 

amioca, and B) inulin HP-amioca; 3:5 at 0.02 (2%) strain and at 1 Hz frquency. 

The short-term development of gel structure was largely dominated by 

aggregation of amylose. The solubilized amylopectin act simply as filler in the continuous 

amylose matrix. At high amylose content, time on set gel was rapid and one could set gel at 

high temperature (Case et al., 1998). The gel rigidity decreased progressively as amylose 

content decreased resulting in high amylose gel had higher G′. The G′ of gelatinized hylon 

(high amylose) starch as much higher than those of the normal corn and amioca (high 

amylopectin) gel. This was likely the result of amylose and the rigid granular structure of 

gelatinized starch. Reddy et al., (1994) reported that G′ and G′′ values were highly correlated 

with amylose content of starch. 

145

tan δ 

1 

0.1 

0 10 20 30 40 

Tempearature ( 

50 60 70 80 

o C) 


polymer concentration 15% (w/w) amioca gel, inulin HP-amioca; 3:5 at 0.02 (2%) 

strain and at 1 Hz frequency. 

7.7 Thermal properties of inulin-starch mixed gel 

amioca 

HP: amioca; 3:5 

Modulated differential scanning calorimetry (MDSC) is a recent extension of 

conventional DSC. MDSC is a thermo-analytical technique which sinusoidally complex 

temperature program is used instead of conventional linear heating or cooling temperature 

(Reading et al., 1992). Whereas, DSC is only capable of measuring the total heat flow, 

MDSC provides the total heat flow, the reversible (heat capacity of component) and the nonreversible 

(kinetic component) heat flow. (Gallagher, 1997; Hill et al., 1998). The glass 

transition is detected on the reversible heat flow. Th non-reversible heat flow transition is 

kinetic and temperature dependent. 

In this experiment inulin-starch mixed gel was formed under different conditions 

which were at room temperature and 4 o C for 24 h before anylsis. All thermal parameters, 

including onset (To), peak temperature (Tp) and the enthalpy (∆H ) changes in total and nonreversing 

exotherm were listed in Table 47. The appearance of non-reversing endo-, 

exotherms resulted from the irreversible process (e.g., molecular relaxation, cold 

crystallization, evaporation, decomposition, and thermoset cure) and non equillibrium phase 

transition (e.g., melting crystallization and reorganization) (Gallagher, 1997; Wunderlich, 

146

1997). Roos (1995) mentioned that DSC data could be used to calculat enthalpy changes and 

heat capacities. First order phase transitions produced endotherm or exotherm peaks and step 

change in heat flow. First order phase transition of carbohydrates in foods included melting, 

crystallization and gelatinization of starch. Starch retrogradation could be detected from 

increasing size of melting endotherm in DSC thermogram. In addition, De Meuter et al. 

(1999) suggested that the exothermicity of crystallization process of starch could never be 

measured in situ by conventional DSC because the crystallization rate was too low. However 

MDSC enabled measurement of the kinetic of starch crystallization. 

Thermal properties of inulin HP gel, hylon (high amylose) gel, corn gel and 

amioca (amylopectin) gel and mixed gel was shown in Table 47 and Fig. 50-52. Both total 

and non-reversing heat flows displayed concurrently exothermic changes. Fig. 50 

corresponded to MDSC thermogram for inulin HP gel which showed reversing, non-reversing 

and total heat flow history. The reversible endothermic transition was observed on the 

reversing heat flow signal. The glass transition of inulin HP gel at room temperature was 

64.9 o C, with heat capacity of 0.035 J/g/ o C, and for gel formed at 4 o C was 58.4 o C, with heat 

capacity of 0.038 J/g/ o C (Table 47). The heat capacity values varied between 0.035 and 0.038 

J/g/ o C, indicating a small-magnitude transition. This also indicated that inulin HP gel was not 

a strong network such as helix, or stacking formation gel. From the previous results by 

microscope (F0g.31A and 32A) and Frank and Coussement (1997) it was suggested that 

inulin gel formed a particle gel network. Non-reversing and total heat flow showed exotherm 

peak around 72.6 o C and a small endotherm prior Tonset of exotherm at around 60 o C. By 

appearence, inulin gel was a reversible gel. Gel became soft when heating, and changed from 

semi-solid phase to sol and finally dissolved at around 80 o C. At early endotherm around 60 o C 

it was suggested that the water mobility in gel structure with increase. Interaction of water 

with inulin might decrease and suggested in a softer gel. Kinetically molecular reorganization 

was responsible for endotherm seen in non-reversing heat flow. Virtually reversible transition 

was also observed similarly at a range of 60-70 o C. According to Rabel et al. (1999), 

polymorphic conversion or transformations with occur via decomposition after melting of the 

component or via a melt followed by recrystallization. 

When warming up the gel exotherm was observed. This might due to the energy 

released from water-water hydrogen bond formation and water-inulin interaction. At around 

90 o C, exotherm was diminished due to fully dissolved which related of inulin by water-inulin 

147

interaction. Gel transition was from semi-solid to resilience gel and fully dissolves colloid 

system. This correlated with the observation of fully dissolved gel. 

All gels, except inulin HP, did not have heat transition on reversing heat flow. 

Some gels showed multiple exotherms of total heat flow and non-reversible heat flow, e.g., 

hylon, inulin HP-corn; 1:5, inulin HP-corn-amioca; 1:2:3, amioca at 4 o C, inulin HP-amioca 

1:5. These might suggest multiple kinetic characteristics of these inulin-starch mixed gels. 

Hylon gel and inulin HP-hylon mixed gel showed single exotherm. Hylon and 

inulin HP-hylon mixed gel which gelled at room temperature had To and Tp lower than those 

for 4 o C. But enthalpy of gel stored at 4 o C was higher than gel stored at room temperature 

(Table 47). The exotherm of inulin HP-hylon mixed gel had To and Tp higher than hylon gel 

which was similar to inulin HP gel system (Fig. 51). The thermal events showed the main 

effect of inulin on gel properties. Gel strength of inulin HP-hylon mixed gel was lower than 

hylon gel. This might be useful if one would like to reduce gel stiffness and thus decreasing 

the amylose retrogradation. 

148

Table 47 Thermal properties of inulin-starch mixed gel as analyzed by Modulated 

Differential Scanning Calorimetry 

Sample Gel a Nonreversing Exotherm b 

Total Exotherm b 

To ( o C) ∆H (J/g) Tp ( o C) To ( o C) ∆H (J/g) Tp ( o C) 

HP RT 63.9 + 0.3 7.07 + 0.23 72.4 + 0.1 64.1 + 0.4 8.50 + 0.35 72.6 + 0.7 

149 

4 o C 61.8 + 2.3 9.27 + 3.75 70.0 + 0.9 61.9 + 2.2 9.0 + 3.6 69.9 + 1.0 

Hylon RT 56.7 + 1.1 12.79+ 8.2 65.8 + 1.0 56.5 + 0.7 13.8 + 8.2 65.7 + 1.0 

92.0 + 6.9 1.31 + 0.73 93.4 + 6.8 92.1 + 6.9 1.30+ 0.8 93.4 + 6.8 

4 64.2+ 0.5 20.08 + 2.9 71.6 + 0.7 64.3 + 0.6 19.4 + 2.4 71.6 + 0.7 

o C 

110.5+ 1.8 0.20 + 0.0 111.6 + 1.7 110.6+ 1.9 0.2 + 0.0 111.6+ 1.7 

HP-hylon, RT 63.4 + 2.3 13.67+ 3.5 71.3 + 0.7 63.5 + 2.2 12.9 + 3.6 71.2 + 0.6 

1:5 4 o C 66.4 + 1.2 3.47 + 2.50 73.2 + 1.5 66.5 + 1.2 2.61 + 1.4 73.1 + 1.6 

HP-hylon, RT 64.8 + 1.4 14.53+ 7.1 72.3 + 1.3 65.0 + 1.2 13.3 + 6.7 72.3 + 1.3 

1:10 4 o C 66.3 + 0.5 6.39 + 1.0 73.0 + 0.3 66.8 + 0.0 5.3 + 0.1 73.0 + 0.3 

corn RT 61.0 + 0.0 18.87+ 6.4 68.4 + 0.5 61.1 + 0.1 17.6 + 6.1 68.3 + 0.46 

4 o C 65.9 + 0.3 14.0 + 0.3 71.6 + 0.1 66.5 + 1.3 11.9 + 1.3 71.5 + 0.1 

HP-corn, RT 62.8 + 1.5 12.37+ 7.1 68.5 + 1.6 62.9 + 1.5 12.0 + 6.6 68.5 + 1.5 

1:5 

104.4 + 1.9 1.59+ 0.52 105.7 + 2.0 104.3+ 2.0 1.60 + 0.5 105.7+ 2.0 

4 66.2 + 0.6 6.02 + 4.42 72.9 + 0.5 66.4 + 0.7 5.0 + 3.5 72.9 + 0.5 

o C 

93.5 + 4.9 0.97 + 0.02 97.99 + 3.5 94.9+ 5.4 0.6 + 0.1 98.2 + 3.2 

HP-corn- RT 64.7 + 0.5 8.59+ 9.2 71.2 + 2.6 64.7 + 0.3 8.0 + 7.8 71.1 + 2.7 

amioca, 

111.3 + 2.6 2.85+ 3.8 112.5+ 2.7 111.4+ 2.7 2.1 + 2.7 112.5+ 2.7 

1:2:3 4 o C 62.7 + 0.3 12.0 + 0.5 71.5 + 1.7 63.2 + 0.0 10.8 + 0.6 72.0 + 1.1 

113.6 + 5.0 2.76 + 3.6 115.4+ 4.1 114.1+ 4.3 1.7 + 2.1 115.4+ 4.0 

Amioca RT 63.4 + 0.8 21.9 + 3.5 69.4 + 0.9 63.4 + 0.8 21.6 + 3.4 69.4 + 0.9 

4 o C 59.9 + 2.3 31.3 + 0.5 68.7 + 0.6 60.1 + 2.0 31.8 + 1.9 68.7 + 0.6 

100.2+ 4.6 2.82 + 3.65 102.9 + 2.0 100.4 + 2.0 2.3 + 3.0 102.9+ 2.1 

RT 60.8 + 0.1 5.259 + 4.4 68.6 + 0.2 60.7 + 0.1 5.49 + 5.0 68.6 + 0.2 

89.5 + 3.3 10.17 + 0.5 95.0 + 2.7 89.5 + 3.4 9.6 + 0.1 95.0 + 2.7 

4 o HP-amioca, 

1:5 

C 60.7 + 1.9 11.96+ 1.3 68.9 + 2.3 60.8 + 2.1 11.1 + 1.7 69.0 + 2.4 

90.5 + 3.9 1.86+ 0.3 100.1+ 2.3 95.6+ 4.1 1.75+ 0.7 101.5+ 3.4 

HP-amioca, RT 60.5 + 2.1 8.53+ 2.4 71.4 + 1.0 60.8 + 2.4 7.7 + 3.3 71.4 + 1.1 

3:5 4 o C 63.3 + 1.4 5.5 + 1.1 72.8 + 1.6 64.3 + 1.5 3.8 + 0.5 72.9 + 1.7 

a gel condition: RT= gel formation at room temperature 24 h, 4 o C = gel formation at 4 o C 24h. 

b Onset (To), peak (Tp), as well as enthalpy changes for total, nonreversing flow (∆H )

Total heat flow (mW) 

-0.3 

-0.4 

-0.5 

-0.6 

-0.7 

-0.8 

-0.9 

0 20 40 60 

Temperature ( 

80 100 120 

o C) 

0 

-0.1 

-0.2 

-0.3 

-0.4 

-0.5 

-0.6 

Rev heat flow (mW) 

Nonrev heat flow (mW) 

Figure 50 MDSC thermogram of inulin HP gel which formed gel at room temperature for 1 

Total heat flow 

-0.4 

-0.5 

-0.6 

-0.7 

-0.8 

-0.9 

-1 

-1.1 

-1.2 

day. 

Non –reversing heat flow 

Total heat flow 

Reversing heat flow 

Inulin HP 

Hylon 

Inulin HP: hylon, 1:10 

Inulin HP: hylon, 1:5 

-1.3 

0 20 40 60 

Temperature ( 

80 100 120 

oC) Figure 51 Total heat flow from MDSC thermogram of hylon (high amylose) starch gel and 

inulin HP-hylon mixed gel which formed gel at room temperature for 1 day. 

150

Total heat flow (mW) 

-0.2 

-0.3 

-0.4 

-0.5 

-0.6 

-0.7 

-0.8 

-0.9 

-1 

-1.1 

-1.2 

Inulin HP: corn: amioca, 1:2:3 

Corn 

Inulin HP: amioca, 1:5 

Inulin HP: corn, 1:5 

Amioca 

0 20 40 60 80 100 120 140 


Figure 52 Total heat flow from MDSC thermogram of amioca (high amylopectin), corn 

starch gel and inulin HP-amioca, inulin HP-corn and inulin HP-corn-amioca 

mixed gel which formed gel at room temperature for 1 day. 

Single system of corn gel and amioca gel showed single exotherm, but in inulin 

Hp-corn and inulin HP-corn-amioca mixed system they had two exotherms. Also, gels at 4 o C 

had higher To and Tp than gels at room temperature. Inulin HP-amioca 1:5, and inilin HP-corn- 

amioca; 1:2:3 showed double exotherms. But inulin HP-amioca; 3:5 which had high inulin 

HP content showed a single exotherm. Inulin added into mixed starch gel introduced a 

weaker gel as compared to single starch system. Typical amioca gel was sticky. When inulin 

was added, the gel became soft and loss stickiness and adhesive (glueminess) with increasing 

inulin concentration. These results related with gel properties from texture analyzer as 

mentioned in section 7.4. 

Inulin HP-starch mixed gel showed second exotherm at high temperature around 

100 o C (Fig. 52). The content of amylopectin in amioca and corn was 98% and 72%, 

respectively, thus the content of amylopectin in HP-amioca > HP-corn-amioca > and HPcorn. 

At high temperature (~ 100 o C), water in gel might vaporize and causing on increase in 

concentration of amylopectin and inulin. Also, at high temperature inulin was completely 

dissolved as mentioned before. More complex of amylopectin-inulin might occur which 

151

could released an energy. This could be observed by the enthalpy value of HP-amioca > HPcorn-amioca 

> and HP-corn which were 9.6, 2.1 and 1.6, respectively. However, the second 

exotherm of inulin HP-corn mixed gel had higher temperature than the others. Because this 

gel had lower amylopectin content than other. The second exotherm might occur under the 

condition which inulin and amylopectin were interacted at high temperature (more than 

100 o C). Zemiri and Kokini (2003a) studied the interaction of pre-solubilized inulin powder 

and gelatinized waxy maize starch (WMS) powder by DSC found phase separation occurred 

with the thermogram exhibited two transitions. One at low temperature (~ 25-30 o C at 11%- 

14% moisture content) was related to pure inulin and the one high temperature (~ 100-110 o C 

at 11%-14% moisture content) was related to amylopectin. Moreover, the ratio of inulin to 

WMS did not effect the Tg. The addition of inulin had no plasticizing effects on WMS. The 

only one plasticizer acting in mixed inulin-WMS sample was water. 

In our case the inulin-starch gelled at high moisture (75%-82%) did not show the 

reverse heat flow transition but did show the double exotherm. The low temperature range 

exotherm was close to inulin HP exotherm. The high temperature range exotherm was close 

to amylopectin transition from Zemiri and Kokini (2003a). The second exotherm pattern did 

not appear in amylose system. This might due to that both inulin and amylose are rather 

linear polymer which might not have strong interaction. While the amylopectin have branch 

chain which might encourage the interaction with inulin. These results demonstrated that 

composition of gel (e.g., inulin, amylose and amylopectin) and the temperature of gel 

formation had significant effect on thermal and rheological properties of inulin-satrch mixed 

gel. 

Phase separation and thermodynamic incompatibility of these biopolymers is still 

need to be addressed. 

152

CONCLUSION 

Early and late harvest of Jerusalem artichokes tuber resulted in different composition 

of the extracted inulin. We found that there was a decrease in the inulin DP 11-20 

components and an increase in fructose and sucrose for the 20-weeks matured tubers as 

compared with 16–18 weeks, which had higher DP fractions and lower contents of sugar. 

However, the dry matter, which estimate carbohydrate content or tubers yield, of early 

harvested tubers was lower than that of late maturity tubers. Therefore, 18 weeks seems to be 

the optimum harvest time for locally grown Jerusalem artichokes on the basis of the amount 

of high DP inulin and dry matter content. 

Jerusalem artichoke tubers were stored at different temperatures for 12 weeks. It was 

found that storage temperature and duration affected the quality and DP distribution profile of 

the inulin. After 4-6 weeks storage at 2 o C and 5 o C an increase in sucrose and DP 3-10, with a 

decrease DP > 10 fractions were observed. Whereas inulin composition remained unchanged 

with frozen storage (-18 o C) for 3 months. A series of second fructan, inulo-n-ose appeared in 

cold storage tubers. Inulo-n-ose increased as storage time increased. Inulo-tri-ose (3′) and 

inulo-tetra-ose (4′) were predominant throughout the 12-week study period. There were no 

second fructan series found with frozen storage. 

Extraction of inulin from Jerusalem artichoke with high ethanol concentration (>70%) 

tended to provide high content of reducing sugar and low DP fraction. The high DP inulin 

molecule was left in the pulp of extract. The water extraction obtained high DP fraction and 

low content of sugar than ethanol extraction. Ethanol concentration at 70% or higher was 

more effective to precipitate inulin from an extract. Yield and content of high DP inulin (DP> 

30) increased as concentration of ethanol increasing. 

Inulin solubility increased with elevated temperature. The solubility depended on 

several factors such as physical characteristics and purity of inulin. Gel formation ability 

depended on concentration and the amount of high DP fractions. As the concentration and 

high DP fractions of inulin increased gel formation ability increased. The extracted Jerusalem 

artichoke inulin (inulin JAT) did not form gel even at 25% (w/w) concentration. Commercial 

inulin (Raftiline HP) could form gel at 25% (w/w) concentration at 50 o C. This could due to 

inulin JAT had higher sugar and more of low DP content than inulin HP. Inulin gel exhibited 

shear thinning properties by steady shear measurement. 

153

For inulin-starch mixed system, both inulin JAT and inulin HP did not affect the 

pasting temperature of starch gel, but resulted in decreasing gel viscosity. Rheological study 

showed that gel strength, firmness, yield point and modulus decreased while gel brittleness 

increased as inulin content in the mixed system increased. Increase inulin content in the 

inulin-starch mixed system resulted in decreasing storage modulus of the mixed gel. Inulin 

exerted more effect on Hylon (high amylose starch) and corn starch than on Amioca (high 

amylopectin) starch. Light microscope and SEM of inulin gel showed a particle gel system 

that might interfere and disrupt the starch gel network. Results from modulated differential 

scanning calorimeter (MDSC) suggested inulin-amylopectin complex might occur while 

dissolved at high temperature (about 100 o C or higher). This, however, was not observed for 

inulin-amylose mixed sytem. 

154

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168

APPENDIX 

169

Appendix Table 1 Result of Multivariate test of harvest time effect on inulin composition of 

16,18 and 20 weeks maturity second crop Jerusalem artichoke tubers. 

Multivariate Tests(c) 

Effect Value F 

Hypothesis 

df Error df Sig. 

Intercept Pillai's Trace 1.000 3747.723(a) 3.000 1.000 .012 

HT 

Wilks' Lambda .000 3747.717(a) 3.000 1.000 .012 

Hotelling's Trace 11243.152 3747.717(a) 3.000 1.000 .012 

Roy's Largest 

Root 

11243.152 3747.717(a) 3.000 1.000 .012 

Pillai's Trace 1.754 4.744 6.000 4.000 .077 

Wilks' Lambda .000 16.743(a) 6.000 2.000 .057 

Hotelling's Trace 644.750 .000 6.000 .000 . 

Roy's Largest 

Root 

641.667 427.778(b) 3.000 2.000 .002 

a Exact statistic 

b The statistic is an upper bound on F that yields a lower bound on the significance level. 

c Design: Intercept+HT 

170

Appendix Table 2 The analysis result of the effect of of harvest time on inulin composition of 

16,18 and 20 weeks maturity second crop Jerusalem artichoke tubers. 

Tests of Between-Subjects Effects 

Dependent Type III Sum 

Source 

Variable of Squares df Mean Square F Sig. 

Corrected Model monosaccharide 4.596(a) 2 2.298 901.235 .000 

glucose .534(b) 2 .267 205.802 .001 

fructose 8.229(c) 2 4.114 665.402 .000 

sucrose 2.109(d) 2 1.054 15.938 .025 

DP 3-10 7.023E-02(e) 2 3.512E-02 .143 .872 

DP 11-20 9.607(f) 2 4.803 93.570 .002 

DP 21-30 .536(g) 2 .268 4.948 .112 

DP >30 .245(h) 2 .122 1.471 .359 

% Dry matter 28.868(i) 2 14.434 21.491 .017 

total solid 1.083(j) 2 .542 .448 .676 

Intercept monosaccharide 24.604 1 24.604 9648.529 .000 

glucose 2.710 1 2.710 2088.518 .000 

fructose 11.016 1 11.016 1781.588 .000 

sucrose 376.517 1 376.517 5691.864 .000 

DP 3-10 13334.963 1 13334.963 54273.355 .000 

DP 11-20 4868.941 1 4868.941 94849.501 .000 

DP 21-30 589.645 1 589.645 10885.755 .000 

DP >30 122.582 1 122.582 1472.756 .000 

% Dry matter 3077.229 1 3077.229 4581.710 .000 

total solid 3197.042 1 3197.042 2645.828 .000 

Harvest Time monosaccharide 4.596 2 2.298 901.235 .000 

glucose .534 2 .267 205.802 .001 

fructose 8.229 2 4.114 665.402 .000 

sucrose 2.109 2 1.054 15.938 .025 

DP 3-10 7.023E-02 2 3.512E-02 .143 .872 

DP 11-20 9.607 2 4.803 93.570 .002 

DP 21-30 .536 2 .268 4.948 .112 

DP >30 .245 2 .122 1.471 .359 

% Dry matter 28.868 2 14.434 21.491 .017 

total solid 1.083 2 .542 .448 .676 

a R Squared = .998 (Adjusted R Squared = .997) 

b R Squared = .993 (Adjusted R Squared = .988) 

c R Squared = .998 (Adjusted R Squared = .996) 

d R Squared = .914 (Adjusted R Squared = .857) 

e R Squared = .087 (Adjusted R Squared = -.522) 

f R Squared = .984 (Adjusted R Squared = .974) 

g R Squared = .767 (Adjusted R Squared = .612) 

h R Squared = .495 (Adjusted R Squared = .159) 

i R Squared = .935 (Adjusted R Squared = .891) 

j R Squared = .230 (Adjusted R Squared = -.283) 

171

Appendix Table 3 Result of Multivariate test of storage temperature effect on inulin 

composition of 21-weeks maturity first crop Jerusalem artichoke tubers. 


Effect Value F Hypothesis df Error df Sig. 


Wilks' Lambda .000 12085.541(a) 4.000 1.000 .007 


Roy's Largest 

Root 

48342.163 12085.541(a) 4.000 1.000 .007 

TEMP Pillai's Trace 2.894 20.487 12.000 9.000 .000 

Wilks' Lambda .000 244.897 12.000 2.937 .000 

Hotelling's Trace . . 12.000 . . 

Roy's Largest 

Root 

70434.075 52825.556(b) 4.000 3.000 .000 



c Design: Intercept+TEMP 

172

Appendix Table 4 The analysis result of the effect of storage temperature on inulin 

composition of 21-weeks maturity first crop Jerusalem artichoke tubers. 



Source 

Variable 

of Squares df Mean Square F Sig. 


173 

glucose 8.185(b) 3 2.728 369.964 .000 

fructose 80.691(c) 3 26.897 12366.513 .000 

sucrose 77.417(d) 3 25.806 682.465 .000 

DP 3_10 202.395(e) 3 67.465 521.065 .000 

DP 11_20 76.153(f) 3 25.384 2032.780 .000 

DP 21_30 110.952(d) 3 36.984 869.957 .000 

DP > 30 97.160(g) 3 32.387 468.353 .000 


glucose 207.061 1 207.061 28076.102 .000 

fructose 63.845 1 63.845 29354.023 .000 

sucrose 223.556 1 223.556 5912.212 .000 

DP 3_10 9884.180 1 9884.180 76340.452 .000 

DP 11_20 6960.230 1 6960.230 557375.785 .000 

DP 21_30 1500.698 1 1500.698 35300.161 .000 

DP > 30 572.234 1 572.234 8275.263 .000 

TEMP monosaccharide 39.240 3 13.080 1090.004 .000 

glucose 8.185 3 2.728 369.964 .000 

fructose 80.692 3 26.897 12366.513 .000 

sucrose 77.417 3 25.806 682.465 .000 

DP 3_10 202.395 3 67.465 521.065 .000 

DP 11_20 76.153 3 25.384 2032.780 .000 

DP 21_30 110.952 3 36.984 869.957 .000 

DP > 30 97.160 3 32.387 468.353 .000 



c R Squared = 1.000 (Adjusted R Squared = 1.000) 


e R Squared = .997 (Adjusted R Squared = .996) 


g R Squared = .997 (Adjusted R Squared = .995)


174 

composition of 16-weeks maturity second crop Jerusalem artichoke tubers. 






TEMP 

Wilks' Lambda .000 6878.507(a) 4.000 1.000 .009 


Roy's Largest 

Root 

27514.027 6878.507(a) 4.000 1.000 .009 

Pillai's Trace 2.222 2.143 12.000 9.000 .129 

Wilks' Lambda .000 63.306 12.000 2.937 .003 


Roy's Largest 

Root 

21863.943 

16397.957 

(b) 

4.000 3.000 .000 



c Design: Intercept+TEMP




Dependent Type III Sum of 

Source 

Variable 

Squares df Mean Square F Sig. 


glucose 1.685(b) 3 .562 .784 .562 

fructose 58.534(c) 3 19.511 168.382 .000 

sucrose 57.755(d) 3 19.252 33.006 .003 

DP 3-10 51.477(e) 3 17.159 14.689 .013 

DP 11-20 126.921(f) 3 42.307 31.332 .003 

DP 21-30 42.338(g) 3 14.113 67.955 .001 

DP >30 12.362(h) 3 4.121 39.526 .002 


glucose 5.298 1 5.298 7.395 .053 

fructose 56.180 1 56.180 484.833 .000 

sucrose 499.912 1 499.912 857.078 .000 

DP 3-10 16031.242 1 16031.242 13723.910 .000 

DP 11-20 6400.330 1 6400.330 4740.019 .000 

DP 21-30 904.826 1 904.826 4356.932 .000 

DP >30 196.813 1 196.813 1887.893 .000 


glucose 1.685 3 .562 .784 .562 

fructose 58.534 3 19.511 168.382 .000 

sucrose 57.755 3 19.252 33.006 .003 

DP 3-10 51.477 3 17.159 14.689 .013 

DP 11-20 126.921 3 42.307 31.332 .003 

DP 21-30 42.338 3 14.112 67.955 .001 

DP >30 12.362 3 4.121 39.526 .002 


b R Squared = .370 (Adjusted R Squared = -.102) 







175


composition of 18-weeks maturity second crop Jerusalem artichoke 

tubers. 





Intercept Pillai's Trace 1.000 .000(a) 5.000 .000 . 

TEMP 

Wilks' Lambda .000 .000(a) 5.000 .000 . 

Hotelling's Trace 437292909 

730207.800 

.000(a) 5.000 .000 . 

Roy's Largest 

Root 

437292909 

730207.800 

.000(a) 5.000 .000 . 

Pillai's Trace 2.930 16.691 15.000 6.000 .001 

Wilks' Lambda .000 22841.924 15.000 .401 .104 


Roy's Largest 

Root 

174087866 

75288.800 

696351467 

0115.520(b) 

176 

5.000 2.000 .000 





177 




Mean 

Source 

Variable 

of Squares df Square F Sig. 


glucose 1.067(b) 3 .356 3.317 .138 

fructose 30.736(c) 3 10.245 2.299 .219 

sucrose 39.399(d) 3 13.133 35.022 .002 

DP 3-10 107.401(e) 3 35.800 286.432 .000 

DP 11-20 73.988(f) 3 24.663 3.099 .152 

DP 21-30 37.867(g) 3 12.622 25.582 .005 

DP >30 12.742(h) 3 4.247 58.462 .001 


glucose 12.903 1 12.903 120.310 .000 

fructose 38.632 1 38.632 8.668 .042 

sucrose 419.486 1 419.486 1118.666 .000 

DP 3-10 15782.426 1 15782.426 126272.036 .000 

DP 11-20 6903.125 1 6903.125 867.349 .000 

DP 21-30 1012.275 1 1012.275 2051.580 .000 

DP >30 128.801 1 128.801 1772.901 .000 


glucose 1.067 3 .356 3.317 .138 

fructose 30.736 3 10.245 2.299 .219 

sucrose 39.399 3 13.133 35.022 .002 

DP 3-10 107.401 3 35.800 286.432 .000 

DP 11-20 73.988 3 24.663 3.099 .152 

DP 21-30 37.867 3 12.622 25.582 .005 

DP >30 12.742 3 4.247 58.462 .001 








h R Squared = .978 (Adjusted R Squared = .961)


178 

composition of 20 weeks maturity second crop Jerusalem artichoke tubers. 






Wilks' Lambda .000 4647.455(a) 4.000 1.000 .011 


Roy's Largest 

Root 

18589.822 4647.455(a) 4.000 1.000 .011 

TEMP 

Pillai's Trace 2.777 9.357 12.000 9.000 .001 

Wilks' Lambda .000 22.654 12.000 2.937 .014 


Roy's Largest 

Root 

1724.344 1293.258(b) 4.000 3.000 .000 






tubers. 



Mean 

Source 

Variable 

Squares df Square F Sig. 


glucose .479(b) 3 .160 1.464 .351 

fructose 7.190© 3 2.397 16.464 .010 

sucrose 38.101(d) 3 12.700 94.911 .000 

DP 3-10 273.616(e) 3 91.205 85.809 .000 

DP 11-20 65.701(f) 3 21.900 281.314 .000 

DP 21-30 78.694(g) 3 26.231 111.992 .000 

DP >30 29.780(h) 3 9.927 73.962 .001 


glucose 1.075 1 1.075 9.852 .035 

fructose 21.780 1 21.780 149.614 .000 

sucrose 497.228 1 497.228 3715.857 .000 

DP 3-10 18331.338 1 18331.338 17246.734 .000 

DP 11-20 5995.125 1 5995.125 77008.671 .000 

DP 21-30 946.125 1 946.125 4039.385 .000 

DP >30 126.962 1 126.962 945.978 .000 


glucose .479 3 .160 1.464 .351 

fructose 7.190 3 2.397 16.464 .010 

sucrose 38.101 3 12.700 94.911 .000 

DP 3-10 273.616 3 91.205 85.809 .000 

DP 11-20 65.701 3 21.900 281.314 .000 

DP 21-30 78.694 3 26.231 111.992 .000 

DP >30 29.780 3 9.927 73.962 .001 









179

Appendix Table 11 Result of Multivariate test of storage temperature and time effect on 

inulin composition of 21-weeks maturity first crop Jerusalem artichoke 

tubers. 






Wilks' Lambda .000 39317.913(a) 8.000 50.000 .000 


Roy's Largest Root 6290.866 39317.913(a) 8.000 50.000 .000 


Wilks' Lambda .032 28.583(a) 16.000 100.000 .000 

Hotelling's Trace 22.153 67.842 16.000 98.000 .000 

Roy's Largest Root 21.790 138.909(b) 8.000 51.000 .000 

TIME Pillai's Trace 2.416 6.311 40.000 270.000 .000 

Wilks' Lambda .008 10.991 40.000 220.739 .000 



TEMP * TIME Pillai's Trace 3.292 3.985 80.000 456.000 .000 

Wilks' Lambda .001 7.578 80.000 325.690 .000 





c Design: Intercept+TEMP+TIME+TEMP * TIME 

180

Appendix Table 12 The analysis result of the effect of storage temperature and time effect on 

inulin composition of 21-weeks maturity first crop Jerusalem artichoke 

tubers. 



Source 

Variable 



glucose 59.021(b) 18 3.279 3.566 .000 

fructose 626.238(c) 18 34.791 36.424 .000 

sucrose 601.690(d) 18 33.427 13.506 .000 

DP 3-10 1014.854(e) 18 56.381 15.951 .000 

DP 11-20 430.111(f) 18 23.895 15.145 .000 

DP 21-30 922.470(g) 18 51.248 78.081 .000 

DP >30 447.305(h) 18 24.850 26.059 .000 


glucose 1704.726 1 1704.726 1854.111 .000 

fructose 498.635 1 498.635 522.045 .000 

sucrose 1393.557 1 1393.557 563.075 .000 

DP 3-10 68363.599 1 68363.599 19340.676 .000 

DP 11-20 55639.772 1 55639.772 35265.657 .000 

DP 21-30 12619.974 1 12619.974 19227.583 .000 

DP >30 6188.384 1 6188.384 6489.502 .000 


glucose 18.450 2 9.225 10.033 .000 

fructose 332.896 2 166.448 174.262 .000 

sucrose 448.946 2 224.473 90.700 .000 

DP 3-10 205.697 2 102.848 29.097 .000 

DP 11-20 263.032 2 131.516 83.358 .000 

DP 21-30 514.207 2 257.104 391.719 .000 

DP >30 140.889 2 70.445 73.872 .000 

TIME monosaccharide 41.270 5 8.254 3.915 .004 

glucose 22.771 5 4.554 4.953 .001 

fructose 39.849 5 7.970 8.344 .000 

sucrose 28.268 5 5.654 2.284 .058 

DP 3-10 361.073 5 72.215 20.430 .000 

DP 11-20 19.967 5 3.993 2.531 .039 

DP 21-30 114.912 5 22.982 35.016 .000 

DP >30 137.082 5 27.416 28.750 .000 

TEMP * TIME monosaccharide 177.185 10 17.718 8.403 .000 

glucose 15.924 10 1.592 1.732 .096 

fructose 230.324 10 23.032 24.114 .000 

sucrose 118.403 10 11.840 4.784 .000 

DP 3-10 429.544 10 42.954 12.152 .000 

181

Appendix Table 12 (Cont’d) 

Source 



Variable 


DP 11-20 131.749 10 13.175 8.351 .000 

DP 21-30 258.356 10 25.836 39.363 .000 

DP >30 156.634 10 15.663 16.426 .000 










inulin composition of 16-weeks maturity second crop Jerusalem 







182 

Wilks' Lambda .000 76293.565(a) 10.000 10.000 .000 




Wilks' Lambda .000 99.220(a) 20.000 20.000 .000 




Wilks' Lambda .000 12.626 50.000 48.971 .000 



TEMP * TIME Pillai's Trace 5.858 2.688 100.000 190.000 .000 

Wilks' Lambda .000 9.632 100.000 83.455 .000 





c Design: Intercept+TEMP+TIME+TEMP * TIME


inulin composition of 16-weeks maturity second crop Jerusalem artichoke tubers. 



Mean 

Source 

Variable 



glucose 70.434(b) 18 3.913 7.427 .000 

fructose 494.220(c) 18 27.457 313.951 .000 

sucrose 336.647(d) 18 18.703 24.369 .000 

DP 3-10 579.270(e) 18 32.182 17.740 .000 

DP 11-20 585.949(f) 18 32.553 33.787 .000 

DP 21-30 129.547(g) 18 7.197 36.655 .000 

DP >30 63.901(h) 18 3.550 22.688 .000 


glucose 88.989 1 88.989 168.905 .000 

fructose 597.490 1 597.490 6831.956 .000 

sucrose 2073.182 1 2073.182 2701.345 .000 

DP 3-10 55377.126 1 55377.126 30527.190 .000 

DP 11-20 23613.031 1 23613.031 24508.093 .000 

DP 21-30 3527.280 1 3527.280 17964.728 .000 

DP >30 910.248 1 910.248 5817.257 .000 


glucose 19.322 2 9.661 18.337 .000 

fructose 271.896 2 135.948 1554.484 .000 

sucrose 277.150 2 138.575 180.562 .000 

DP 3-10 83.061 2 41.530 22.894 .000 

DP 11-20 472.706 2 236.353 245.312 .000 

DP 21-30 43.386 2 21.693 110.485 .000 

DP >30 10.349 2 5.175 33.070 .000 


glucose 18.058 5 3.612 6.855 .001 

fructose 78.646 5 15.729 179.853 .000 

sucrose 12.959 5 2.592 3.377 .024 

DP 3-10 119.427 5 23.885 13.167 .000 

DP 11-20 28.492 5 5.698 5.914 .002 

DP 21-30 13.644 5 2.729 13.898 .000 

DP >30 15.607 5 3.121 19.949 .000 

TEMP * TIME monosaccharide 149.565 10 14.957 20.888 .000 

glucose 31.647 10 3.165 6.007 .000 

fructose 100.316 10 10.032 114.706 .000 

sucrose 45.472 10 4.547 5.925 .000 

DP 3-10 312.211 10 31.221 17.211 .000 

DP 11-20 76.977 10 7.698 7.990 .000 

183


Source 


184 


Mean 

Variable 


DP 21-30 72.121 10 7.212 36.732 .000 

DP >30 36.952 10 3.695 23.616 .000 










j R Squared = .955 (Adjusted R Squared = .912) 


inulin composition of 18-weeks maturity second crop Jerusalem 







Wilks' Lambda .000 142424.673(a) 10.000 10.000 .000 




Wilks' Lambda .000 28.503 50.000 48.971 .000 




Wilks' Lambda .000 76.577(a) 20.000 20.000 .000 



TIME * TEMP Pillai's Trace 5.669 2.487 100.000 190.000 .000 

Wilks' Lambda .000 8.700 100.000 83.455 .000 





c Design: Intercept+TIME+TEMP+TIME * TEMP

Appendix Table 16 The analysis result of the effect of storage temperature and time on inulin 


tubers. 



Mean 

Source 

Variable 



glucose 26.959(b) 18 1.498 3.487 .005 

fructose 303.761(c) 18 16.876 11.411 .000 

sucrose 356.842(d) 18 19.825 14.408 .000 

DP 3-10 1161.583(e) 18 64.532 86.501 .000 

DP 11-20 1040.911(f) 18 57.828 12.292 .000 

DP 21-30 319.727(g) 18 17.763 82.021 .000 

DP >30 93.883(h) 18 5.216 48.812 .000 


glucose 55.218 1 55.218 128.543 .000 

fructose 271.901 1 271.901 183.849 .000 

sucrose 1864.039 1 1864.039 1354.783 .000 

DP 3-10 64658.646 1 64658.646 86670.731 .000 

DP 11-20 23713.698 1 23713.698 5040.571 .000 

DP 21-30 3270.851 1 3270.851 15103.636 .000 

DP >30 627.523 1 627.523 5872.788 .000 


glucose 9.714 5 1.943 4.523 .007 

fructose 91.874 5 18.375 12.424 .000 

sucrose 88.091 5 17.618 12.805 .000 

DP 3-10 432.446 5 86.489 115.933 .000 

DP 11-20 245.104 5 49.021 10.420 .000 

DP 21-30 128.252 5 25.650 118.445 .000 

DP >30 31.273 5 6.255 58.534 .000 

% Dry matter 19.456 5 3.891 .631 .679 

total solid 58.650 5 11.730 353.762 .000 


glucose .620 2 .310 .721 .499 

fructose 111.306 2 55.653 37.630 .000 

sucrose 161.290 2 80.645 58.613 .000 

DP 3-10 44.026 2 22.013 29.507 .000 

DP 11-20 502.500 2 251.250 53.406 .000 

DP 21-30 46.316 2 23.158 106.936 .000 

DP >30 4.965 2 2.483 23.233 .000 

TIME * TEMP monosaccharide 137.000 10 13.700 5.249 .001 

glucose 15.867 10 1.587 3.694 .007 

fructose 87.536 10 8.754 5.919 .000 

sucrose 107.325 10 10.733 7.800 .000 

DP 3-10 677.684 10 67.768 90.839 .000 

DP 11-20 282.441 10 28.244 6.004 .000 

185

Appendix Table 16 (Cont,d) The analysis result of the effect of storage temperature and time 

Source 

on inulin composition of 18-weeks maturity second crop 

Jerusalem artichoke tubers. 



Mean 

Variable 


DP 21-30 145.008 10 14.501 66.960 .000 

DP >30 57.555 10 5.755 53.864 .000 









i R Squared = .287 (Adjusted R Squared = -.388) 

j R Squared = .995 (Adjusted R Squared = .991) 


inulin composition of 20-weeks maturity 2 nd crop Jerusalem artichoke 

tubers. 






Wilks' Lambda .000 1228335.574(a) 10.000 7.000 .000 




Wilks' Lambda .000 94.377 40.000 28.399 .000 




Wilks' Lambda .000 269.834(a) 20.000 14.000 .000 



TIME * TEMP Pillai's Trace 5.946 4.052 80.000 112.000 .000 

Wilks' Lambda .000 23.152 80.000 52.965 .000 





c Design: Intercept+TIME+TEMP+TIME * TEMP 

186


inulin composition of 20-weeks maturity 2 nd crop Jerusalem artichoke 

tubers. 


Type III Sum 

Mean 

Source Dependent Variable of Squares df Square F Sig. 


glucose 53.435(b) 15 3.562 5.222 .001 

fructose 179.971(c) 15 11.998 12.773 .000 

sucrose 288.228(d) 15 19.215 6.466 .000 

DP 3-10 1421.928(e) 15 94.795 99.761 .000 

DP 11-20 712.193(f) 15 47.480 7.257 .000 

DP 21-30 392.203(g) 15 26.147 5.836 .001 

DP >30 100.549(h) 15 6.703 98.023 .000 


glucose 33.210 1 33.210 48.683 .000 

fructose 202.541 1 202.541 215.625 .000 

sucrose 1752.446 1 1752.446 589.690 .000 

DP 3-10 59586.613 1 59586.613 62707.899 .000 

DP 11-20 19519.317 1 19519.317 2983.560 .000 

DP 21-30 2857.636 1 2857.636 637.829 .000 

DP >30 517.519 1 517.519 7567.796 .000 


glucose 17.078 4 4.270 6.259 .003 

fructose 61.282 4 15.320 16.310 .000 

sucrose 43.824 4 10.956 3.687 .026 

DP 3-10 299.959 4 74.990 78.918 .000 

DP 11-20 121.936 4 30.484 4.660 .011 

DP 21-30 82.700 4 20.675 4.615 .011 

DP >30 19.664 4 4.916 71.886 .000 


glucose 12.501 2 6.251 9.163 .002 

fructose 86.776 2 43.388 46.191 .000 

sucrose 185.791 2 92.895 31.259 .000 

DP 3-10 364.407 2 182.203 191.748 .000 

DP 11-20 389.931 2 194.965 29.801 .000 

DP 21-30 147.966 2 73.983 16.513 .000 

DP >30 27.879 2 13.939 203.840 .000 

TIME * TEMP monosaccharide 94.942 8 11.868 54.370 .000 

glucose 21.913 8 2.739 4.015 .009 

fructose 31.737 8 3.967 4.223 .007 

sucrose 57.276 8 7.160 2.409 .064 

DP 3-10 757.324 8 94.666 99.624 .000 

DP 11-20 200.241 8 25.030 3.826 .011 

187



Type III Sum 

Mean 


DP 21-30 159.924 8 19.991 4.462 .005 

188 

DP >30 52.978 8 6.622 96.839 .000 










j R Squared = .983 (Adjusted R Squared = .966)

Appendix Table 19 Result of Multivariate of the effect of solvent extraction on inulin 

composition. 





Intercept Pillai's Trace .999 2427.255(a) 8.000 11.000 .000 

189 

Wilks' Lambda .001 2427.255(a) 8.000 11.000 .000 



SOL Pillai's Trace .725 .852 16.000 24.000 .623 

Wilks' Lambda .398 .803(a) 16.000 22.000 .669 

Hotelling's Trace 1.201 .751 16.000 20.000 .717 

Roy's Largest Root .829 1.243(b) 8.000 12.000 .354 

RATIO Pillai's Trace .963 1.394 16.000 24.000 .225 

Wilks' Lambda .209 1.636(a) 16.000 22.000 .140 



TIME Pillai's Trace .503 1.393(a) 8.000 11.000 .298 

Wilks' Lambda .497 1.393(a) 8.000 11.000 .298 



SOL * RATIO Pillai's Trace 1.142 .699 32.000 56.000 .861 

Wilks' Lambda .239 .625 32.000 42.161 .915 


Roy's Largest Root .993 1.738(b) 8.000 14.000 .175 

SOL * TIME Pillai's Trace .751 .901 16.000 24.000 .577 

Wilks' Lambda .359 .919(a) 16.000 22.000 .561 



RATIO * TIME Pillai's Trace .845 1.098 16.000 24.000 .407 

Wilks' Lambda .309 1.099(a) 16.000 22.000 .411 



SOL * RATIO * TIME Pillai's Trace 1.145 .702 32.000 56.000 .859 

Wilks' Lambda .224 .659 32.000 42.161 .888 





c Design: Intercept+SOL+RATIO+TIME+SOL * RATIO+SOL * TIME+RATIO * 

TIME+SOL * RATIO * TIME

Appendix Table 20 The analysis result of the effect of solvent extraction on inulin 

composition. 



Mean 

Source 

Variable 



glucose 105.098(b) 17 6.182 2.630 .024 

fructose 55.145(c) 17 3.244 .690 .776 

sucrose 57.171(d) 17 3.363 1.097 .422 

DP3-10 356.597(e) 17 20.976 1.159 .379 

DP11-20 616.563(f) 17 36.268 .792 .683 

DP21-30 21.484(g) 17 1.264 .316 .989 

DP>30 8.981(h) 17 .528 2.190 .054 


glucose 259.049 1 259.049 110.188 .000 

fructose 968.869 1 968.869 205.997 .000 

sucrose 3953.475 1 3953.475 1289.822 .000 

DP3-10 84245.063 1 84245.063 4652.880 .000 

DP11-20 22050.270 1 22050.270 481.443 .000 

DP21-30 1845.848 1 1845.848 461.041 .000 

DP>30 89.145 1 89.145 369.620 .000 

SOL monosaccharide 50.613 2 25.307 2.158 .144 

glucose 13.397 2 6.699 2.849 .084 

fructose 6.206 2 3.103 .660 .529 

sucrose 4.277 2 2.138 .698 .511 

DP3-10 6.090 2 3.045 .168 .847 

DP11-20 29.661 2 14.831 .324 .728 

DP21-30 4.415 2 2.208 .551 .586 

DP>30 1.322 2 .661 2.741 .091 

RATIO monosaccharide 91.921 2 45.960 3.920 .039 

glucose 21.570 2 10.785 4.587 .025 

fructose 23.005 2 11.503 2.446 .115 

sucrose .914 2 .457 .149 .863 

DP3-10 134.574 2 67.287 3.716 .045 

DP11-20 119.093 2 59.547 1.300 .297 

DP21-30 .028 2 .014 .003 .997 

DP>30 2.347 2 1.173 4.865 .020 


glucose 24.917 1 24.917 10.598 .004 

fructose 3.062 1 3.062 .651 .430 

sucrose 1.166 1 1.166 .381 .545 

DP3-10 63.044 1 63.044 3.482 .078 

DP11-20 52.611 1 52.611 1.149 .298 

190


Source 



Mean 

Variable 


DP21-30 .321 1 .321 .080 .780 

DP>30 .019 1 .019 .079 .781 

SOL * RATIO monosaccharide 36.954 4 9.238 .788 .548 

glucose 15.006 4 3.752 1.596 .219 

fructose 15.263 4 3.816 .811 .534 

sucrose 6.370 4 1.593 .520 .722 

DP3-10 64.611 4 16.153 .892 .489 

DP11-20 108.565 4 27.141 .593 .672 

DP21-30 1.372 4 .343 .086 .986 

DP>30 .543 4 .136 .562 .693 

SOL * TIME monosaccharide 5.387 2 2.694 .230 .797 

glucose 11.795 2 5.898 2.509 .109 

fructose .869 2 .435 .092 .912 

sucrose 19.194 2 9.597 3.131 .068 

DP3-10 12.524 2 6.262 .346 .712 

DP11-20 151.769 2 75.885 1.657 .219 

DP21-30 3.386 2 1.693 .423 .662 

DP>30 .866 2 .433 1.796 .195 

RATIO * TIME monosaccharide 23.090 2 11.545 .985 .393 

SOL * RATIO * 

TIME 

glucose 10.284 2 5.142 2.187 .141 

fructose 1.153 2 .577 .123 .885 

sucrose 15.616 2 7.808 2.547 .106 

DP3-10 48.313 2 24.156 1.334 .288 

DP11-20 13.623 2 6.812 .149 .863 

DP21-30 10.561 2 5.280 1.319 .292 

DP>30 3.577 2 1.788 7.415 .004 

monosaccharide 

33.014 4 8.254 .704 .599 

glucose 8.129 4 2.032 .864 .504 

fructose 5.586 4 1.397 .297 .876 

sucrose 9.634 4 2.408 .786 .549 

DP3-10 27.443 4 6.861 .379 .821 

DP11-20 141.240 4 35.310 .771 .558 

DP21-30 1.401 4 .350 .088 .985 

DP>30 .307 4 .077 .319 .862 



c R Squared = .394 (Adjusted R Squared = -.177) 


191


f R Squared = .428 (Adjusted R Squared = -.112) 

g R Squared = .230 (Adjusted R Squared = -.498) 


Appendix Table 21 Result of Multivariate test of inulin precipitate method effect inulin yield. 






Treatment 

Wilks' Lambda .000 7677.853(a) 2.000 6.000 .000 


Roy's Largest 

Root 

2559.284 7677.853(a) 2.000 6.000 .000 

Pillai's Trace 1.588 4.492 12.000 14.000 .005 

Wilks' Lambda .013 7.636(a) 12.000 12.000 .001 


Roy's Largest 

Root 

27.103 31.621(b) 6.000 7.000 .000 



c Design: Intercept+TRT 

Appendix Table 22 The analysis result of the effect of inulin precipitate method on inulin 

yield. 


Type III Sum 

Mean 


Corrected Model inulin weight 105.281(b) 6 17.547 5.088 .025 

Intercept inulin weight 1190.118 1 1190.118 345.083 .000 

Treatment inulin weight 105.281 6 17.547 5.088 .025 

Error inulin weight 24.142 7 3.449 



192

Appendix Table 23 Result of Multivariate test of inulin precipitate with different solvent 

effect on inulin composition at 4 o C. 




Wilks' Lambda .002 142.717(a) 4.000 1.000 .063 



TRT Pillai's Trace 2.227 2.161 12.000 9.000 .127 

Wilks' Lambda .000 4.344 12.000 2.937 .130 






Appendix Table 24 Result of Multivariate test of inulin precipitate with different solvent 

effect on inulin composition at 25 o C. 






Wilks' Lambda .027 11.849(a) 3.000 1.000 .210 



TRT Pillai's Trace .971 .629 6.000 4.000 .709 

Wilks' Lambda .046 1.225(a) 6.000 2.000 .514 






193

Appendix Table 25 The analysis result of the effect on inulin composition of inulin precipitate 

with different solvent at 4 o C. 



Source 

Variable 

Squares df Mean Square F Sig. 


glucose 2.882(b) 3 .961 .621 .637 

fructose 85.165(c) 3 28.388 6.816 .047 

sucrose 2.817(d) 3 .939 .883 .522 

DP 3-10 350.711(e) 3 116.904 2.712 .180 

DP 11-20 1.352(f) 3 .451 .030 .992 

DP 21-30 106.133(g) 3 35.378 2.756 .176 

DP >30 157.641(h) 3 52.547 44.175 .002 


glucose 5.429 1 5.429 3.510 .134 

fructose 596.506 1 596.506 143.223 .000 

sucrose 1.437 1 1.437 1.351 .310 

DP 3-10 8554.320 1 8554.320 198.428 .000 

DP 11-20 5532.994 1 5532.994 362.776 .000 

DP 21-30 2718.425 1 2718.425 211.798 .000 

DP >30 1279.168 1 1279.168 1075.361 .000 

TRT monosaccharide 57.326 3 19.109 1.839 .280 

glucose 2.882 3 .961 .621 .637 

fructose 85.165 3 28.388 6.816 .047 

sucrose 2.817 3 .939 .883 .522 

DP 3-10 350.711 3 116.904 2.712 .180 

DP 11-20 1.352 3 .451 .030 .992 

DP 21-30 106.133 3 35.378 2.756 .176 

DP >30 157.641 3 52.547 44.175 .002 




d R Squared = .398 (Adjusted R Squared = -.053) 





194

Appendix Table 26 The analysis result of the effect on inulin composition of inulin 

precipitate with different solvent at 25 o C. 



Source 

Variable 


Corrected Model monosaccharide .891(a) 2 .446 .009 .991 

glucose .007(b) 2 .004 .019 .981 

fructose .763(a) 2 .382 .008 .992 

sucrose .659(c) 2 .329 .200 .829 

DP 3-10 .922(d) 2 .461 .002 .998 

DP 11-20 14.858(e) 2 7.429 .309 .755 

DP 21-30 2.277(f) 2 1.139 .018 .982 

DP >30 11.038(g) 2 5.519 .139 .876 


glucose 1.344 1 1.344 7.231 .074 

fructose 160.167 1 160.167 3.567 .155 

sucrose 5.704 1 5.704 3.465 .160 

DP 3-10 4030.560 1 4030.560 21.515 .019 

DP 11-20 4653.735 1 4653.735 193.697 .001 

DP 21-30 3126.340 1 3126.340 49.013 .006 

DP >30 1710.619 1 1710.619 42.981 .007 

TRT monosaccharide .891 2 .446 .009 .991 

glucose .007 2 .004 .019 .981 

fructose .763 2 .382 .008 .992 

sucrose .659 2 .329 .200 .829 

DP 3-10 .922 2 .461 .002 .998 

DP 11-20 14.857 2 7.429 .309 .755 

DP 21-30 2.277 2 1.139 .018 .982 

DP >30 11.038 2 5.519 .139 .876 

a R Squared = .006 (Adjusted R Squared = -.657) 







195

Appendix Table 27 Result of Multivariate test of inulin precipitate with different solvent at 

4 o C effect on inulin composition in supernatant. 




Wilks' Lambda .001 180.542(a) 4.000 1.000 .056 



TRT Pillai's Trace 1.720 1.007 12.000 9.000 .508 

Wilks' Lambda .011 1.087 12.000 2.937 .541 






Appendix Table 28 Result of Multivariate test of inulin precipitate with different solvent at 

25 o C effect on inulin composition in supernatant. 






Wilks' Lambda .013 24.535(a) 3.000 1.000 .147 



TRT Pillai's Trace 1.002 .669 6.000 4.000 .686 

Wilks' Lambda .132 .585(a) 6.000 2.000 .741 






196

Appendix Table 29 The analysis result of the effect of inulin precipitate with different 

solvent at 4 o C effect on inulin composition in supernatant. 



Source 

Variable 



197 

glucose 44.263(b) 3 14.754 .678 .610 

fructose 8.130(c) 3 2.710 .484 .712 

sucrose 42.022(d) 3 14.007 .856 .532 

DP 3-10 145.099(e) 3 48.366 .990 .482 

DP 11-20 74.676(f) 3 24.892 1.954 .263 

DP 21-30 62.540(g) 3 20.847 .583 .657 

DP >30 4.156(h) 3 1.385 .789 .560 


glucose 618.992 1 618.992 28.439 .006 

fructose 14.285 1 14.285 2.549 .186 

sucrose 23.427 1 23.427 1.432 .298 

DP 3-10 19526.832 1 19526.832 399.869 .000 

DP 11-20 5968.874 1 5968.874 468.650 .000 

DP 21-30 235.445 1 235.445 6.580 .062 

DP >30 2.868 1 2.868 1.633 .270 

TRT monosaccharide 29.594 3 9.865 1.733 .298 

glucose 44.263 3 14.754 .678 .610 

fructose 8.130 3 2.710 .484 .712 

sucrose 42.022 3 14.007 .856 .532 

DP 3-10 145.099 3 48.366 .990 .482 

DP 11-20 74.676 3 24.892 1.954 .263 

DP 21-30 62.540 3 20.847 .583 .657 

DP >30 4.156 3 1.385 .789 .560 








h R Squared = .372 (Adjusted R Squared = -.099) 

i R Squared = .315 (Adjusted R Squared = -.199)

Appendix Table 30 The analysis result of the effect of inulin precipitate with different 

solvent at 25 o C effect on inulin composition in supernatant. 



Source 

Variable 


Corrected Model monosaccharide 35.889(a) 2 17.945 .988 .468 

glucose 23.516(b) 2 11.758 .232 .806 

fructose 2.914(c) 2 1.457 .156 .862 

sucrose 14.547(d) 2 7.274 .151 .866 

DP 3-10 8.564(e) 2 4.282 .045 .957 

DP 11-20 12.078(f) 2 6.039 1.034 .455 

DP 21-30 3.171(g) 2 1.586 .018 .982 

DP >30 .521(h) 2 .261 .110 .899 


glucose 274.186 1 274.186 5.421 .102 

fructose 31.556 1 31.556 3.378 .163 

sucrose 148.205 1 148.205 3.071 .178 

DP 3-10 12401.488 1 12401.488 129.937 .001 

DP 11-20 3710.604 1 3710.604 635.187 .000 

DP 21-30 561.440 1 561.440 6.383 .086 

DP >30 6.573 1 6.573 2.780 .194 

TRT monosaccharide 35.889 2 17.945 .988 .468 

glucose 23.516 2 11.758 .232 .806 

fructose 2.914 2 1.457 .156 .862 

sucrose 14.547 2 7.274 .151 .866 

DP 3-10 8.564 2 4.282 .045 .957 

DP 11-20 12.078 2 6.039 1.034 .455 

DP 21-30 3.171 2 1.586 .018 .982 

DP >30 .521 2 .261 .110 .899 

a R Squared = .397 (Adjusted R Squared = -.005) 







h R Squared = .068 (Adjusted R Squared = -.553) 

i R Squared = .145 (Adjusted R Squared = -.425) 

198

CURRICULUM VITAE 

NAME :Mrs. Wanpen Saengthongpinit 

BIRTH DATE : November 5, 1972 

BIRTH PLACE : Ratchaburi, Thailand 

EDUCATION : YEAR INSTITUTION DEGREE 

1995 King Mongkut’s Institute 

of Technology Ladkrabang 

B.Sc. (Agricultural Industry) 

1998 Mahidol Univ. M.Sc. (Food and Nutrition 

for Development) 

2005 Kasetsart Univ. Ph.D. (Food Science) 

POSITION : Lecturer 

WORK PLACE : Department of Food Science and Technology, Faculty of Agricultural 

Technology, Phetchaburi Rajabhat University 

SCHOLARSHIP/AWARDS: 

The Royal Bangkok Sport Club, Education Scholarship 

The Coordination Office of Research and Development of 

1996-1998 

Royal Thai Army, Research Fund 

The Third Place of Outstanding Research Project Competition 

1996-1998 

“Development of Special Ration for Special Operation of Thai 

Soldiers” From Army Medical Department, Royal Thai Army 1998 

Phetchaburi Rajabhat University, Education scholarship. 2001-2003 

Postgraduate Education and Research Development in Postharvest 

Technology Program, Kasetsart University, Research Fund 2001 

The Split-mode program, National Center for Genetic Engineering 

and Biotechnology (BIOTEC), Thailand, Research Fund 2002 

Graduate school of Kasetsart University, Research Fund 2002 

199

thesis

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