Lynne Wong's PhD thesis

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Table 4.16. Comparison of the Brix-free water of a sample in its original state with that in a finely divided state. Sample Brix-free water in the original state/% Mean/% Brix-free water of finely cut sample/% Mean/% Stalk fibre 1 10.89 10.66 10.54 10.72 10.59 10.62 Stalk fibre 2 11.63 10.26 11.82 11.73 11.34 10.80 Stalk fibre 3 10.57 12.19 10.15 10.36 11.33 11.76 Stalk fibre 4 12.41 12.47 12.82 12.61 13.57 13.02 Stalk fibre 5 14.08 12.76 14.23 14.16 14.21 13.49 Stalk fibre 6 16.97 16.86 16.96 16.96 17.28 17.07 Rind fibre 1 8.57 8.86 8.12 8.34 8.67 8.77 Rind fibre 2 8.38 8.89 8.52 8.45 9.21 9.05 Rind fibre 3 8.51 8.47 8.56 8.54 8.47 8.47 Rind fibre 4 11.53 12.82 12.44 11.98 12.22 12.52 Rind fibre 5 13.89 13.66 14.60 14.24 13.78 13.72 Rind fibre 6 12.66 11.59 12.90 12.78 12.08 11.83 Dry leaf fibre 1 14.96 14.27 14.89 14.93 14.38 14.32 Dry leaf fibre 2 12.77 13.08 13.14 12.96 13.21 13.15 Dry leaf fibre 3 12.92 12.31 12.85 12.89 12.84 12.57 Green leaf fibre 1 13.55 13.63 13.10 13.32 13.03 13.33 Green leaf fibre 2 13.32 12.31 12.87 13.09 12.56 12.44 Green leaf fibre 3 13.58 14.07 13.42 13.50 13.37 13.72 Top fibre 1 14.80 15.39 15.91 15.35 15.72 15.55 Top fibre 2 17.03 15.55 16.13 16.58 15.36 15.46 Top fibre 3 16.07 15.98 15.57 15.82 15.02 15.50 4.4.11 Sample size and precision of the method In general, the use of 6 g samples and the corresponding 110 g contact solution, with the ratio of contact solution/sample set at 20, had been adopted for all previous Brix-free water determinations. However, with pith sample, a test sample of 6 g is very bulky, making it difficult to dry and handle when filtering after contact with the sucrose solution. The sample size was therefore reduced to 3.5 g in the above experiment. The filtrate obtained was found sufficient to satisfy the test volume requirement of Brix measurement as described in Section 4.4.2. 142
A sample size of 3.5 g with 75 g contact solution was henceforth adopted for pith samples. 4.5 OTHER METHODS OF DETERMINING BRIX-FREE WATER So far in the literature and here, the method used to determine Brix-free water in cane fibre involves mixing dried fibre with a solution of 10° Brix sucrose solution. From the increase in Brix as detected by a refractometer, the amount of water absorbed by the fibre is calculated leading to the Brix-free water value of the fibre. In theory, the fibre can be made to contact a solution other than that of sucrose, the increase in the analyte as detected by an appropriate analytical technique, should also lead to the Brix-free water value of the fibre, provided that the technique is sensitive enough to detect the increase in the analyte. In this context, various analytes and techniques were explored, for example, lithium by flame photometry, conductivity by using a conductivity meter, chloride by amperometric potentiometric titrimetry, lactose by high performance ion chromatography and pol by saccharimeter. The details of these experiments are given in Appendix 4. All these alternative methods (except the polarimetric one) still require further development to give acceptable Brix-free water results. Although the polarimetric method showed promise, it is much more time-consuming and requires special equipment, this is the reason why the refractometric method was preferred in this study. 4.6 EXPERIMENTAL The following procedure was followed to determine the Brix-free water content in fibres of sugar cane component parts. 4.6.1 Materials 4.6.1.1 Samples examined Brix-free water was determined in duplicate for the three replicates of four cane varieties (R 579, R 570, M 1557/70 and M 1400/86) aged 52, 44 and 36 weeks. For each age, nine cane component parts, namely dry leaf fibre and fines, green leaf fibre and fines, top fibre, rind fibre and fines and stalk fibre and pith obtained as described in Section 3.4.3 were studied. For comparison, those nine component parts of R 570 aged 52, 44 and 37 weeks harvested in 2001 were also studied. 143
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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
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 and 174: Table 4.2. Determination of Brix-fr
Page 175 and 176: Table 4.3. Comparison of Brix-free
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: Qin and White’s finding was confi
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
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
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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
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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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