Lynne Wong's PhD thesis

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This is attributable to possible residual sucrose in the fibre sample, despite repeated washing and pressing during the fibre extraction process, resulting in an over-estimation of the Brix increase in the sucrose contacting solution, and hence an over-estimation of the Brix-free water content. Reports exist on the use of detergent to clean plant tissue prior to certain analyses, e.g. Van Soest (1963) experimented with detergents to dissolve forage nitrogen in the preparation of fibrous portions of plant tissue of low nitrogen content for analysis such as lignin, and found cetyl trimethyl ammonium bromide in strongly acid solution or sodium lauryl sulfate in slightly alkaline solutions most effective. However, one must ensure that any residual reagent does not affect the subsequent Brix-free water determination. It would be much simpler to effect a blank determination in distilled water, and subtract the Brix value of the sample blank from that of the test solution. Since it would be difficult to adjust to have the same mass of distilled water in the blank as that of the contact solution in the test solution, let alone to have the same mass of fibre sample in the blank and test solution, bearing in mind the hygroscopic nature of cellulose fibre; a corrected blank is needed to compensate for the differences in masses. The advantage of the corrected blank is that if one sample is used several times in the same experiment for different test purposes, only one blank will be required. Thus, if w 1 and w 3 are the mass of sample in the blank and test solution respectively, and w 2 is the mass of distilled water in the blank and w 4 , the mass of the contacting solution in the test solution; p 1 and p 2 are the Brix of the sample blank before and after equilibrium, and p 3 and p 4 are the Brix of the test solution before and after equilibrium, the corrected blank, b, is given by b = p 2 w 2 w 3 /(w 1 w 4 ) and the net Brix increase by p = p 4 – b. Hence the Brix-free water in the sample is given by BFW = [100 w 4 (1 – p 3 p -1 )]/w 3 . Results obtained from almost sucrose-free fibre samples (Table 4.3) confirmed that the samples still had high residual sucrose content as evidenced by the high Brix p 2 after equilibration with distilled water, and the Brix-free water results are now 30-40% lower than those obtained had the sample blank not been incorporated in the method. Most other workers performed their studies on bagasse which probably has a low residual sucrose. 122
Table 4.3. Comparison of Brix-free water determined in fibre samples with and without the incorporation of a blank. Determination of blank value Sample Mass of empty Mass of bottle + Mass of bottle + sample + Mass of sample/g Mass of Brix before Mean p 1 Brix after Mean p 2 Adjusted blank (b) bottle/g sample/g 110 g distilled water/g w 1 dist. H 2O/g p 1 p 2 p 2w 2w 3/(w 1w 4) w 2 1b Stalk fibre 216.48 222.69 336.55 6.21 113.86 0.00, 0.00, 0.00 0.000 0.04, 0.04, 0.03 0.037 0.035 2b Stalk pith 217.78 223.62 337.51 5.84 113.89 0.000 0.04, 0.04 0.040 0.039 3b Rind fibre 217.03 223.28 334.74 6.25 111.46 0.000 0.04, 0.04, 0.04 0.040 0.039 4b Rind fines 212.97 219.10 331.97 6.13 112.87 0.000 0.03, 0.03, 0.03 0.030 0.028 5b Dry leaf fibre 225.64 232.26 345.44 6.62 113.18 0.000 0.05, 0.06, 0.06 0.057 0.056 6b Dry leaf fines 215.08 221.66 333.87 6.58 112.21 0.000 0.07, 0.07, 0.05 0.063 0.057 Determination of Brix-free water in sample Sample Mass of bottle Mass of bottle + Mass of bottle + sample + Mass of sample/g Mass of Brix before Mean p 3 Brix after Mean p 4 net p Brix-free water Brix-free water empty/g sample/g 110 g 10º Brix solution/g w 3 soln./g p 3 p 4 p 4 - b [100w 4(1-p 3 p -1 )]/w 3 without w 4 sample blank 1 Stalk fibre 216.48 222.48 339.67 6.00 117.19 10.04, 10.04,10.05 10.048 10.14, 10.15, 10.14 10.143 10.109 11.71 18.36 2 Stalk pith 217.78 223.69 341.58 5.91 117.89 10.05, 10.05, 10.06 10.048 10.16, 10.16 10.160 10.121 14.37 21.99 3 Rind fibre 217.03 223.34 337.78 6.31 114.44 10.048 10.15, 10.14, 10.15 10.147 10.107 10.65 17.64 4 Rind fines 212.96 218.90 336.18 5.94 117.28 10.048 10.13, 10.13, 10.13 10.130 10.102 10.56 15.98 5 Dry leaf fibre 225.63 232.12 344.99 6.49 112.87 10.048 10.18, 10.18, 10.18 10.180 10.124 13.05 22.55 6 Dry leaf fines 215.07 221.11 334.15 6.04 113.04 10.048 10.19, 10.19, 10.19 10.190 10.133 15.62 25.48 123
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THE BRIX-FREE WATER CAPACITY AND SO
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dissolved and hydrated waters, and
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ACKNOWLEDGEMENTS I am particularly
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Page 1.5 THE DELETERIOUS EFFECTS OF
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Page 2.2 THE PHENOMENON OF BRIX-FRE
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Page 3.4.3.3 Cane tops 83 3.4.4 Cha
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4.3.3 Temperature at which Brix-fre
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4.6.1 Materials 143 4.6.1.1 Samples
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CHAPTER 6. PROPERTIES OF THE SORBED
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APPENDIX 3. CALCULATIONS LEADING TO
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LIST OF FIGURES Page Figure 1.1. Fi
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Figure 3.1. Glucose and fructose an
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Figure 5.11. Residual plots for the
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total adsorbed water (m) and the pr
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Table 2.18. Moisture content in sug
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Page Table 4.4. Results of the dete
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Page Table 4.24. Analysis of varian
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Page Table 5.13. Table 5.14. Equili
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Table 6.3. Heat of sorption of the
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GLOSSARY OF TERMS Absorption is the
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Filterability of a raw sugar is mea
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Sorption is the generic term used w
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LIST OF MAIN SYMBOLS Symbol Descrip
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s c s Slope of Caurie I isotherm pl
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number of 255, and cane land covere
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Nouvelle Mon In Trésor ustrie and
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Figure 1.3. Cane sampling by core s
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In Mauritius, most of the sugar fac
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are: cane tops, dry and green leave
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1.4 TRENDS IN CANE QUALITY RECEIVED
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campaign was launched to encourage
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The level of extraneous matter in c
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In Australia (Cargill, 1976), cane
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The effect of soil on factory perfo
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leaves increased the level of impur
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• From 1976 to 1980, when the pro
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Clerget purity of molasses 40 Clerg
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CHAPTER 2. IMPACT OF EXTRANEOUS MAT
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Since the extrapolated purity of mo
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Figure 2.1. Jeffco cutter grinder.
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2.1.4 Results The analytical result
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Table 2.3. Analytical results of re
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Table 2.5. Composition of dry trash
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Table 2.7. Predicted factory perfor
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Boiling house recovery 91.0 89.8 89
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0 5 10 15 20 % EM in cane y = 0.572
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% EM in cane 0 5 10 15 20 0 -2 -4 -
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1 y = 0.020 (% D) R 2 = 1.00 = 0.03
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% EM in cane 0 5 10 15 20 0 -2 y =
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esulting in 0.015 unit sucrose loss
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2.2.1 Experimental procedure Cane m
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filter paper, rejecting the first f
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Table 2.9. Effect of increased addi
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Table 2.11. Effect of increased add
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Table 2.13. Effect of increased add
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various components such as stalk fi
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in the presence of dry leaves, if c
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Table 2.17. Moisture content in sug
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CHAPTER 3. SEPARATION OF THE SUGAR
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Table 3.1. It can be seen that the
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Table 3.2. Fibrous physical composi
Page 123 and 124: R 579 R 570 M 1557/70 M 1400/86 74
Page 125 and 126: loosen the fibre. The woody core is
Page 127 and 128: agitate the mixture in the pot, and
Page 129 and 130: Figure 3.7. Custom-built fibre-pith
Page 131 and 132: The extraction of fibres starting f
Page 133 and 134: pre-treatment in a Jeffco cutter-gr
Page 135 and 136: Figure 3.19. Stalk cake washed free
Page 137 and 138: not have many dry leaves attached t
Page 139 and 140: Table 3.5. Masses of cane samples a
Page 141 and 142: Table 3.7. Masses of cane samples a
Page 143 and 144: Table 3.9. Masses of cane component
Page 145 and 146: 3 57.6 126.3 23.7 97.2 31.1 53.8 11
Page 147 and 148: Table 3.12. Material loss (%) from
Page 149 and 150: 3.5.3 Fibre/pith ratios in cane com
Page 151 and 152: Table 3.15. Effect of extraneous ma
Page 153 and 154: Snow (1974) investigated the season
Page 155 and 156: from Figure 2.9 that the change in
Page 157 and 158: Table 3.18. Fibre % cane results by
Page 159 and 160: 110
Page 161 and 162: (a). Dry leaf (b). Green leaf (c).
Page 163 and 164: dry fibre, or a factor, is used in
Page 165 and 166: Steuerwald (1912) applied sucrose s
Page 167 and 168: solution/fibre ratio was lowered fr
Page 169 and 170: leave some residual moisture on the
Page 171 and 172: instead of 150 g of 10° Brix sucro
Page 173: Table 4.2. Determination of Brix-fr
Page 177 and 178: Table 4.4. Results of the determina
Page 179 and 180: In order to test for homogeneity of
Page 181 and 182: Table 4.7. Results of the repeat de
Page 183 and 184: The experiment was repeated with th
Page 185 and 186: e any residual moisture in the samp
Page 187 and 188: By means of the same technique, Won
Page 189 and 190: was still hot. Since the filter was
Page 191 and 192: value determined could be corrected
Page 193 and 194: Qin and White’s finding was confi
Page 195 and 196: A sample size of 3.5 g with 75 g co
Page 197 and 198: Figure 4.4. Fibre samples drying in
Page 199 and 200: - One large fibre sample (rind) of
Page 201 and 202: Table 4.18. Brix-free water values/
Page 203 and 204: Table 4.20. Brix-free water values/
Page 205 and 206: 4.7.3 Statistical analysis It is es
Page 207 and 208: Table 4.23. Analysis of variance (B
Page 209 and 210: pointing out that at 52 weeks old,
Page 211 and 212: The crop of R 570 sampled in 2001 w
Page 213 and 214: 4.7.4. Estimated Brix-free water co
Page 215 and 216: The main difference in the two sets
Page 217 and 218: Table 4.27. Predicted Brix-free wat
Page 219 and 220: 4.8 SUMMARY AND CONCLUSIONS An anal
Page 221 and 222: component parts, and verify the Bri
Page 223 and 224: 3) Thermodynamic, water in equilibr
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Langmuir (1916, 1917, 1918) propose
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to determine the moisture sorption
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Table 5.1. Some commonly used isoth
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Lomauro et al. (1985) found that wi
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and on agricultural products such a
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Bruijn (1963) studied the mass incr
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After measuring the EMC of dry corn
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approached, that is, either by adso
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Table 5.4. Water activity (a w ) of
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5.6.3 Procedure to determine equili
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5.6.4 Results and discussion An exa
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Table 5.8. Equilibrium moisture con
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Table 5.10. Equilibrium moisture co
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Table 5.12. Equilibrium moisture co
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30 o C 45 o C 55 o C 60 o C Water w
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m/m of 96% activity, a w (g/100g dr
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vaporisation generally decreases fr
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30 o C isotherm 45 o C isotherm 55
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4 0 Stalk fibre 5 0 Stalk pith 5 0
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5.6.4.4 Fitting of sorption models
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Table 5.19. Parameters of the sorpt
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Modified GAB Kuhn Iglesias - Chirif
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Table 5.28. Classification of resid
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Stalk fibre Stalk pith Rind fibre 4
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5.6.4.5 Calculated EMC values of re
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Table 5.30. Calculated equilibrium
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m/m of 96% Table 5.32. Calculated e
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Table 5.33. Parameters of the Hailw
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CHAPTER 6. PROPERTIES OF THE SORBED
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where m is the equilibrium moisture
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6.2 THE NUMBER OF ADSORBED MONOLAYE
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6.3 TOTAL SOLID SURFACE AREA AVAILA
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Thus, for each cane component of ea
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abscissa. For each moisture level (
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A similar procedure was followed to
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10 0 Stalk fibre Stalk pith Rind fi
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Moreover, if T β > T hm the proces
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Table 6.5. Characteristic parameter
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Binding energy/kJ (kg mol) -1 2 0 0
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6.8 CALCULATION OF BOUND WATER AND
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The values of K 1 , K 2 and W were
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Table 6.7. Separation of the total
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Table 6.7. (Contd.) Sample 30 o C 4
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3 0 S talk fibre 4 0 Stalk pith 3 0
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3 0 Reconstituted cane at 30 o C 3
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when water is added to dry wood, wh
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It is evident that in some cases ma
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The number of adsorbed monolayers,
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Data in Tables 2.9 and 2.11 show th
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particular fibre is systematically
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Anon. (1985b). Laboratory manual fo
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Blanchi R.H. and A.G. Keller (1952)
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Day D.L. and G.L. Nelson (1965). De
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Heyrovsky J. (1970). Determination
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Kuhn I.J. (1964). A new theoretical
Page 349 and 350:
Madamba P.S., R.H. Driscoll and K.A
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Prinsen Geerligs, H.C. (1897). Stud
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Sing K.S.W., D.H. Everett, R.A.W. H
Page 355 and 356:
Van der Pol C., C.M. Young and K. D
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Lynne Wong's PhD thesis

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