Lynne Wong's PhD thesis
Lynne Wong's PhD thesis Lynne Wong's PhD thesis
Sample Table 4.5. Reproducibility of Brix-free water determinations on fibre samples. Mass of Mass of bottle Mass of bottle + sample Mass of Mass of dis. H 2O/g Brix before Mean p 1 Brix after Mean p 2 Adjusted blank (b) bottle/g empty sample/g + 110 g distilled + water/g sample/g w 1 w 2 p 1 p 2 p 2w 2w 3/(w 1w 4) 1b Rind fibre 225.48 231.24 342.47 5.76 111.23 0.00 0.00 0.00 0.000 0.01 0.01 0.01 0.010 0.009 2b Rind fibre 5.76 111.23 0.009 3b Rind fibre 5.76 111.23 0.009 4b Stalk fibre 226.13 231.45 344.88 5.32 113.43 0.00 0.00 0.00 0.000 0.01 0.01 0.02 0.012 0.012 5b Stalk fibre 5.32 113.43 0.012 6b Stalk fibre 5.32 113.43 0.012 7b Top fibre 202.07 208.02 319.60 5.95 111.58 0.00 0.00 0.00 0.000 0.07 0.06 0.07 0.067 0.061 8b Top fibre 5.95 111.58 0 0 0 0.064 9b Top fibre 5.95 111.58 0.064 10 Green leaf 11 b fibre Green leaf 12 b fibre Green leaf b fibre Sample 220.77 226.34 340.25 5.57 113.91 0.00 0.00 0.00 0.000 0.03 0.03 0.04 0.033 0.039 5.57 113.91 0 0 0 0.035 5.57 113.91 0.036 Mass of bottle Mass of bottle Mass of bottle + sample Mass of Mass of soln./g Brix before Mean p 3 Brix after Mean p 4 net p Brix-free water Standard + + sample/g empty/g sample/g 110 g 10º Brix solution/g w 3 w 4 p 3 p 4 p 4 - b [100w 4(1-p 3 p -1 )]/w 3 deviation 1 Rind fibre 226.29 231.40 344.72 5.11 113.32 9.97 9.98 9.98 9.978 10.07 10.06 10.06 10.067 10.05 17.56 2 Rind fibre 212.64 217.74 326.96 5.10 109.22 5 9.978 10.07 0 10.07 5 10.08 5 10.073 10.06 8 18.30 3 Rind fibre 216.80 222.05 337.42 5.25 115.37 9.978 10.07 0 10.07 0 10.07 0 10.070 10.06 4 18.10 0.383 4 Stalk fibre 216.30 221.49 333.15 5.19 111.66 9.978 0 0 0 10.07 10.07 10.07 10.072 10.06 1 17.49 5 Stalk fibre 225.36 230.53 340.71 5.17 110.18 9.978 5 10.08 10.09 10.09 10.087 10.07 0 20.45 6 Stalk fibre 214.09 219.49 333.30 5.40 113.81 9.978 10.08 10.09 10.08 10.085 10.07 5 19.85 1.565 7 Top fibre 180.48 186.20 303.13 5.72 116.93 9.74 9.74 9.75 9.745 5 9.890 9.900 9.910 9.900 3 9.839 19.50 8 Top fibre 175.38 181.10 292.88 5.72 111.78 0 5 0 9.745 9.900 9.910 9.915 9.908 9.844 19.72 9 Top fibre 178.31 184.33 301.07 6.02 116.74 9.745 9.900 9.910 9.915 9.908 9.844 19.48 0.133 10 Green leaf fibre 11 Green leaf fibre 12 Green leaf fibre 183.50 189.69 298.29 6.19 108.60 9.745 9.87 9.875 9.885 9.877 9.838 16.55 165.85 171.86 288.55 6.01 116.69 9.745 9.86 9.875 9.865 9.867 9.832 17.09 180.63 186.87 305.25 6.24 118.38 9.745 9.87 9.875 9.88 9.875 9.839 18.14 0.809 126
In order to test for homogeneity of samples, fibres of various components of cane were extracted from 15 kg of cane. After removing and discarding the nodes, the rind was separated from the stalk. Fibres were extracted from the rind and the stalk, washed free of sucrose and dried as per the method described in Chapter 3 (Sections 3.4.3.1 and 3.4.3.2). Fibres were separated from the fines/pith as much as possible to obtain four well-separated fractions: stalk fibre (620 g), pith (1175 g), rind fibre (1240 g) and rind fines (830 g). There were also two mixtures: stalk with pith weighing 250 g and rind fibre with fines weighing 915 g. No effort was made to further separate these two mixtures as they would serve to see to what extent reproducible results could be obtained from them. Each of these six fractions was tested in five replicates and one blank determination was effected. Drying was effected in a vacuum oven at 80 °C for 3 hours. To 6 g of sample when cool were added 110 g of 10° Brix sucrose solution. A contact time of one and a half hours was allowed during which period, the sample was shaken every ten minutes. The Brix-free water results are shown in Table 4.6, which indicate that the fractions of stalk fibre, rind fibre, rind fibre + fines, and rind fines were homogeneous, despite such a small sample (6 g) taken from a large sample, e.g. 1240 g, in the case of rind fibres. For the stalk fibre + pith mixture and stalk pith sample, results were not reproducible, probably because of the difficulty associated with drying the pith. Hence the drying condition prior to analysis needed investigation. 4.4.5 Drying conditions prior to analysis When more of the samples which had been examined previously (results shown in Table 4.3) were analysed again two days later for their Brix-free water content under the same analytical conditions and incorporating the blank value, significantly higher results (P < 0.05) were obtained (see Table 4.7). This would indicate that the samples were drier on the second occasion than when first examined, and took up more water to satisfy their Brix-free water capacity. Thus, the overnight vacuum drying at 65 °C so far adopted needed to be re-examined. One green leaf fibre sample was well mixed, and sub-samples of 6 g were weighed into separate bottles. Samples were dried at 65 °C under vacuum of 875 mbar for 2, 4, 6 and 16 hours. The Brix-free water results (Table 4.8) show increasing values from 2, 4, 6 hours reaching the highest value at 16 hours, implying that drying under these conditions for less than 16 hours is insufficient to drive off the moisture originally present in the sample. 127
- 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 and 174: Table 4.2. Determination of Brix-fr
- Page 175 and 176: Table 4.3. Comparison of Brix-free
- Page 177: Table 4.4. Results of the determina
- 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
- Page 225 and 226: Langmuir (1916, 1917, 1918) propose
- Page 227 and 228: to determine the moisture sorption
Sample<br />
Table 4.5. Reproducibility of Brix-free water determinations on fibre samples.<br />
Mass of Mass of bottle Mass of bottle + sample Mass of Mass of dis. H 2O/g Brix before Mean p 1 Brix after Mean p 2 Adjusted blank (b)<br />
bottle/g empty sample/g + 110 g distilled + water/g sample/g w 1 w 2 p 1 p 2 p 2w 2w 3/(w 1w 4)<br />
1b Rind fibre 225.48 231.24 342.47 5.76 111.23 0.00 0.00 0.00 0.000 0.01 0.01 0.01 0.010 0.009<br />
2b Rind fibre 5.76 111.23 0.009<br />
3b Rind fibre 5.76 111.23 0.009<br />
4b Stalk fibre 226.13 231.45 344.88 5.32 113.43 0.00 0.00 0.00 0.000 0.01 0.01 0.02 0.012 0.012<br />
5b Stalk fibre 5.32 113.43 0.012<br />
6b Stalk fibre 5.32 113.43 0.012<br />
7b Top fibre 202.07 208.02 319.60 5.95 111.58 0.00 0.00 0.00 0.000 0.07 0.06 0.07 0.067 0.061<br />
8b Top fibre 5.95 111.58<br />
0 0 0<br />
0.064<br />
9b Top fibre 5.95 111.58 0.064<br />
10 Green leaf<br />
11 b fibre Green leaf<br />
12<br />
b fibre<br />
Green leaf<br />
b fibre<br />
Sample<br />
220.77 226.34 340.25 5.57 113.91 0.00 0.00 0.00 0.000 0.03 0.03 0.04 0.033 0.039<br />
5.57 113.91<br />
0 0 0<br />
0.035<br />
5.57 113.91 0.036<br />
Mass of bottle Mass of bottle Mass of bottle + sample Mass of Mass of soln./g Brix before Mean p 3 Brix after Mean p 4 net p Brix-free water Standard<br />
+<br />
+<br />
sample/g<br />
empty/g sample/g 110 g 10º Brix solution/g w 3 w 4 p 3 p 4 p 4 - b [100w 4(1-p 3 p -1 )]/w 3 deviation<br />
1 Rind fibre 226.29 231.40 344.72 5.11 113.32 9.97 9.98 9.98 9.978 10.07 10.06 10.06 10.067 10.05 17.56<br />
2 Rind fibre 212.64 217.74 326.96 5.10 109.22<br />
5<br />
9.978 10.07 0 10.07 5 10.08 5<br />
10.073 10.06 8<br />
18.30<br />
3 Rind fibre 216.80 222.05 337.42 5.25 115.37 9.978 10.07<br />
0<br />
10.07<br />
0<br />
10.07<br />
0<br />
10.070 10.06<br />
4<br />
18.10 0.383<br />
4 Stalk fibre 216.30 221.49 333.15 5.19 111.66 9.978<br />
0 0 0<br />
10.07 10.07 10.07 10.072 10.06<br />
1<br />
17.49<br />
5 Stalk fibre 225.36 230.53 340.71 5.17 110.18 9.978<br />
5<br />
10.08 10.09 10.09 10.087 10.07 0<br />
20.45<br />
6 Stalk fibre 214.09 219.49 333.30 5.40 113.81 9.978 10.08 10.09 10.08 10.085 10.07<br />
5<br />
19.85 1.565<br />
7 Top fibre 180.48 186.20 303.13 5.72 116.93 9.74 9.74 9.75 9.745<br />
5<br />
9.890 9.900 9.910 9.900<br />
3<br />
9.839 19.50<br />
8 Top fibre 175.38 181.10 292.88 5.72 111.78<br />
0 5 0<br />
9.745 9.900 9.910 9.915 9.908 9.844 19.72<br />
9 Top fibre 178.31 184.33 301.07 6.02 116.74 9.745 9.900 9.910 9.915 9.908 9.844 19.48 0.133<br />
10 Green leaf<br />
fibre<br />
11 Green leaf<br />
fibre<br />
12 Green leaf<br />
fibre<br />
183.50 189.69 298.29 6.19 108.60 9.745 9.87 9.875 9.885 9.877 9.838 16.55<br />
165.85 171.86 288.55 6.01 116.69 9.745 9.86 9.875 9.865 9.867 9.832 17.09<br />
180.63 186.87 305.25 6.24 118.38 9.745 9.87 9.875 9.88 9.875 9.839 18.14 0.809<br />
126
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