Lynne Wong's PhD thesis

2.2.2.5 Estimation of EM in cane using sucrose ratio in dirty cane relative to clean cane
Larrahondo et al. (1998) derived an equation to predict the trash level in cane by assuming
that sucrose in EM was negligible.
⎛
Thus, % EM in cane = 1 sucrosein dirtycane
100
sucrosein cleancane ⎟ ⎞
⎜ −
⎝
⎠
If pol instead of sucrose % cane data from Tables 2.9 – 2.12 are substituted in the above
equation, calculated EM values can be obtained as shown in Table 2.14. When they were
compared with known added EM contents, the equation appeared to apply well to green
and wetted dry leaves, but at high levels of dry and extra dry leaves, the theoretical values
tended to be underestimated.
2.2.2.6 Brix-free water determination in dry leaves
The results of the Brix-free water determination by Mangion and Player’s (1991) method
in dry leaves of the four main cane varieties cultivated in Mauritius are summarised in
Table 2.15. Only M 695/69 had a low Brix-free water of 25.6% while the other three
varieties averaged 28.3% Brix-free water. This is in agreement with the data obtained in
Trial II (Table 2.10), carried out during the rainy season, when the trash was not quite dry,
and averaged a moisture content of 29.8%. In this trial, the phenomenon of Brix-free water
was not observed to be operating, as evidenced by the lower Clerget sucrose % press juice
(14.29%) due to the addition of 5% dry trash than that in the control sample (14.46%). The
same applies to the 10% and 20% addition of dry trash. This is also true for the values of
pol % press juice. The indication would be that the Brix-free water of the dry leaves in this
case was below 29.8%.
This method of determining Brix-free water, gave reproducible results for dry leaves, but
when tried on bagasse samples, the results were not reproducible. According to Qin and
White’s (1991) finding, there are significant differences in the Brix-free water values of
rind, stalk fibre and stalk pith fractions in bagasse sample, which explains why the Brixfree
water value of bagasse is variable. This is probably because in each sample of bagasse
tested there were varying proportions of fibre, pith, rind and trash, each with their own
Brix-free water contents. It would therefore be of interest to separate sugar cane into its
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