Lynne Wong's PhD thesis

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3 0 Stalk fibre 5 0 S talk pith 3 0 Rind fibre 4 0 EMC/% db 2 0 10 EMC/% db 3 0 2 0 EMC/% db 2 0 10 10 0 0 0 . 5 1 1. 5 a w 0 0 0 .5 1 1.5 a w 0 0 0 .5 1 1.5 a w 3 0 Rind fines 5 0 Top fibre 7 0 Dry leaf fibre EMC/% db 2 0 10 EMC/% db 4 0 3 0 2 0 10 EMC/% db 6 0 5 0 4 0 3 0 2 0 10 0 0 0 .5 1 1.5 a w 0 0 0 . 5 1 1. 5 a w 0 0 0 . 5 1 1. 5 a w 4 0 Dry leaf fines 7 0 Green leaf fibre 5 0 Green leaf fines 3 0 6 0 5 0 4 0 EMC/% db 2 0 10 EMC/% db 4 0 3 0 2 0 10 EMC/% db 3 0 2 0 10 0 0 0 . 5 1 1. 5 a w 0 0 0 . 5 1 1. 5 a w 0 0 0 . 5 1 1. 5 a w 30°C 45°C 55°C 60°C Figure 5.9. Experimental sorption isotherms of the nine sugar cane components of R 570 aged 36 weeks. Note the similar behaviour of the nine cane components except those of dry leaf fibre and green leaf fibre. 209
5.6.4.4 Fitting of sorption models to the experimental EMC data In order to determine which isotherm model best described the experimental EMC data obtained, fifteen of the isotherm models listed in Table 5.1 (all except the last two) and the modified Chung-Pfost and modified GAB models in Table 5.2 were fitted to the data. The parameters of the first seven models in Table 5.1 (namely, the Bradley, Caurie I, Caurie II, Halsey, Henderson, Kuhn and Smith models) were estimated by linear regression with Microsoft Excel software whereas those of the GAB model were estimated with the aid of the WATER ANALYSER PROGRAM (Webbtech@bigpond.com). Those of the remaining nine models (namely, BET, modified BET, Day-Nelson, Hailwood-Horrobin, Iglesias-Chirife, Mizrahi, Oswin, modified Chung-Pfost and modified GAB) were estimated by making use of the non-linear regression procedure of SigmaPlot (SPSS Inc.). The values of these parameters together with the calculated regression criteria, i.e. the coefficient of determination R 2 , the mean deviation modulus P and the standard error of the estimate E s , for each model and for each of the nine sugar cane components aged 52 and 36 weeks are shown in Tables 5.19 – 5.27. The BET, Day-Nelson and modified Chung-Pfost models yielded spurious results; they would undoubtedly give poor fit of the experimental results and were not included in the Tables. From Tables 5.19 – 5.27, it can be seen that for the first ten isotherm models, namely the GAB, Hailwood-Horrobin, Henderson, Bradley, Caurie I, Smith, Oswin, Halsey, Caurie II and modified GAB models, the coefficient of determination R 2 approaches one for most temperatures studied (30, 45, 55 and 60 °C) and for all the nine cane component parts of both ages. However, for the last four isotherm models, namely the Kuhn, Iglesias-Chirife, Mizrahi and modified BET models, this was not the case, R 2 was low and mostly below 0.90, and the mean relative deviation modulus P was much greater than 10. They therefore gave a poor fit of the experimental results. As mentioned earlier in Section 5.3.4, for a good fit, R 2 must approach one, the P value must be between 5 and 10, and the standard error of the estimate, E s , must be as small as possible. The poor fit of the last four isotherm models was confirmed from inspection of the isotherm plots for the EMC of stalk fibre of variety R 570 aged 52 weeks shown in Fig 5.10. The complete set of isotherm plots for all the nine components is included on the CD (file: Isotherm plots.xls). The isotherm plots show that in general, apart from the bad fit of the four models mentioned above, the Bradley and Smith models are only applicable within the activity 210
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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
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R 579 R 570 M 1557/70 M 1400/86 74
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loosen the fibre. The woody core is
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agitate the mixture in the pot, and
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Figure 3.7. Custom-built fibre-pith
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The extraction of fibres starting f
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pre-treatment in a Jeffco cutter-gr
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Figure 3.19. Stalk cake washed free
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not have many dry leaves attached t
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Table 3.5. Masses of cane samples a
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Table 3.7. Masses of cane samples a
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Table 3.9. Masses of cane component
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3 57.6 126.3 23.7 97.2 31.1 53.8 11
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Table 3.12. Material loss (%) from
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3.5.3 Fibre/pith ratios in cane com
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Table 3.15. Effect of extraneous ma
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Snow (1974) investigated the season
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from Figure 2.9 that the change in
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Table 3.18. Fibre % cane results by
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110
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(a). Dry leaf (b). Green leaf (c).
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dry fibre, or a factor, is used in
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Steuerwald (1912) applied sucrose s
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solution/fibre ratio was lowered fr
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leave some residual moisture on the
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instead of 150 g of 10° Brix sucro
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Table 4.2. Determination of Brix-fr
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Table 4.3. Comparison of Brix-free
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Table 4.4. Results of the determina
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In order to test for homogeneity of
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Table 4.7. Results of the repeat de
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The experiment was repeated with th
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e any residual moisture in the samp
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By means of the same technique, Won
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was still hot. Since the filter was
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value determined could be corrected
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Qin and White’s finding was confi
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A sample size of 3.5 g with 75 g co
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Figure 4.4. Fibre samples drying in
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- One large fibre sample (rind) of
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Table 4.18. Brix-free water values/
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Table 4.20. Brix-free water values/
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4.7.3 Statistical analysis It is es
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Table 4.23. Analysis of variance (B
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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
Page 225 and 226: Langmuir (1916, 1917, 1918) propose
Page 227 and 228: to determine the moisture sorption
Page 229 and 230: Table 5.1. Some commonly used isoth
Page 231 and 232: Lomauro et al. (1985) found that wi
Page 233 and 234: and on agricultural products such a
Page 235 and 236: Bruijn (1963) studied the mass incr
Page 237 and 238: After measuring the EMC of dry corn
Page 239 and 240: approached, that is, either by adso
Page 241 and 242: Table 5.4. Water activity (a w ) of
Page 243 and 244: 5.6.3 Procedure to determine equili
Page 245 and 246: 5.6.4 Results and discussion An exa
Page 247 and 248: Table 5.8. Equilibrium moisture con
Page 249 and 250: Table 5.10. Equilibrium moisture co
Page 251 and 252: Table 5.12. Equilibrium moisture co
Page 253 and 254: 30 o C 45 o C 55 o C 60 o C Water w
Page 255 and 256: m/m of 96% activity, a w (g/100g dr
Page 257 and 258: vaporisation generally decreases fr
Page 259 and 260: 30 o C isotherm 45 o C isotherm 55
Page 261: 4 0 Stalk fibre 5 0 Stalk pith 5 0
Page 265 and 266: Table 5.19. Parameters of the sorpt
Page 275 and 276: Modified GAB Kuhn Iglesias - Chirif
Page 277 and 278: Table 5.28. Classification of resid
Page 279 and 280: Stalk fibre Stalk pith Rind fibre 4
Page 281 and 282: 5.6.4.5 Calculated EMC values of re
Page 283 and 284: Table 5.30. Calculated equilibrium
Page 285 and 286: m/m of 96% Table 5.32. Calculated e
Page 287 and 288: Table 5.33. Parameters of the Hailw
Page 289 and 290: CHAPTER 6. PROPERTIES OF THE SORBED
Page 291 and 292: where m is the equilibrium moisture
Page 297 and 298: 6.2 THE NUMBER OF ADSORBED MONOLAYE
Page 299 and 300: 6.3 TOTAL SOLID SURFACE AREA AVAILA
Page 301 and 302: Thus, for each cane component of ea
Page 303 and 304: abscissa. For each moisture level (
Page 307 and 308: A similar procedure was followed to
Page 309 and 310: 10 0 Stalk fibre Stalk pith Rind fi
Page 311 and 312: 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
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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
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Van der Pol C., C.M. Young and K. D
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Lynne Wong's PhD thesis

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