Lynne Wong's PhD thesis

Figure 3.1. Glucose and fructose and their condensation product sucrose
(Chen and Chou, 1993).
When the plant needs the stored energy during photosynthesis, the above equations are
reversed (respiration) into active energy for synthesis of fats, proteins, etc., for growth and
production. There is competition within the plant for the products of photosynthesis. On
one hand, glucose and fructose are necessary for rapid growth, and on the other hand,
sucrose is needed for storage. Anything that stimulates growth, such as high temperatures,
adequate water and nutrients, results in low sucrose % cane and a low juice purity.
Conversely, drought and winter conditions result in a high sucrose % cane and high juice
purity. The growing season should therefore be warm with high mean day temperatures of
about 25 to 30 °C, with adequate moisture and high incident solar radiation; whereas the
ripening and harvesting season should be cool, with mean day temperatures of between 10
and 20 °C, frost-free, dry and with high incident radiation.
The composition of the sugar cane depends very much on the cane variety, the region and
the climatic conditions under which it is grown, the degree of maturity of the cane and so
on. Sugar cane is composed mainly of sucrose, fibre and water, usually in the proportion
of about 12%, 15% and 70%, respectively (Anon., 2007), in Mauritius. The remaining
constituents are other sugars (glucose and fructose), inorganic materials, nitrogeneous
substances, gums, waxes and organic acids (Chen and Chou, 1993).
The sugar cane plant can be divided into three parts: roots, stalk and leaves, the
composition of which has been reported by Brown and Blouin (1907) and is shown in
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