Lynne Wong's PhD thesis

Figure 1.5. Determination of extraneous matter in cane from a 400 kg load, with
removed non-cane on both sides and cleaned cane in the middle.
1.3.2 Other cane quality yardsticks
As indicators of cane quality, suspended solids in mixed juice, ash % cane and also sucrose
% dry matter in cane (i.e. sucrose expressed as a percentage of both Brix and fibre in cane)
have been used in South Africa (Lionnet, 1996). Ethanol was first employed by Lionnet
(1986) to measure cane deterioration after harvesting, and the concept of estimated
recoverable crystal in cane (ERC) was introduced by Van Hengel (1974) to estimate the
contribution of each cane consignment towards the total industrial production of a standard
sugar. However, past performance figures are needed to establish factors relating recovery
to each of the three parameters: sucrose, non-sucrose and fibre. The ageing of cane after
harvesting and infection by micro-organisms with the formation of dextran are also criteria
commonly considered.
Clarke and Legendre (1996) listed, as factors for cane quality, the ratio of green tops and
leafy trash, mud or field soil, staleness, stress factors affecting cane (drought, irrigation,
disease, pest, frost) and physical damage of cane stalks by mechanical handling, as well as
the harvesting method, cane transport and delivery procedures.
All the parameters cited above are not systematically measured in the routine control of
factory performance. Fortunately, changes in some measured parameters such as fibre %
cane, sucrose % cane, sucrose/fibre ratio in cane and mixed juice purity, can give an
indirect measure of cane quality received at factories.
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