Lynne Wong's PhD thesis

weighed bag made of mosquito net, and measuring about 30 cm x 15 cm. The bag could
be tied closed with a draw string. After weighing to determine the initial sample mass,
drying was effected in a thermostatic oven at 105 °C to constant mass, after which, the
dried sample was weighed while still hot to calculate the moisture content of the trash.
The results obtained are shown in Tables 2.16 – 2.19. Most of the dry trash samples had a
low moisture content below the typical Brix-free water value of 28.3% found in the main
Mauritian cane varieties. Tables 2.16 – 2.19 show that 93, 94, 85 and 100% of the 192, 98,
60 and 22 samples respectively contain less than 28% moisture.
How the Brix-free water in dry trash affects the cane payment system could be the subject
of a future study.
2.2.4 Conclusions
The effect of processing clean cane stalks together with their attached tops in the
reconstituted whole cane experiment reduced the volume of juice extracted, pol % cane
and sugar recovered, and increased non-sucrose in press juice and fibre % cane. This is in
agreement with the results obtained in Section 2.1.6 except in the case of fibre % cane (see
Fig 2.9), where there was practically no change when measured quantities of cane tops
were added to clean cane, whereas with whole cane, there was an increase of 16% in fibre
% cane. The difference is probably due to the different amount of foliage attached to the
cane tops. The effect produced by whole cane is roughly the same extent as produced by
the presence of 15% green leaves on cane.
Dry leaves absorb more juice than green leaves during cane crushing. The effect of dry
leaves on non-sucrose contents in the juice extracted was of the same order of magnitude
as that produced by green leaves. The overall effect of wet dry leaves on the quality of
both press juice and cane approximated that of green leaves.
Dry leaves have a much higher juice absorbing power than green leaves. When the
moisture content of dry leaves is below a certain critical Brix-free water value, determined
by Mangion and Player’s (1991) method to be 28.3% for typical Mauritian cane varieties,
the press juice obtained in contact with dry leaves had increased the concentrations of
sucrose, Brix and pol (marked bold in Tables 2.2, 2.9 – 2.12), as the trash absorbs water in
preference to juice during pressing to satisfy its Brix-free water capacity. This implies that
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