Cane deterioration in the field, factory storage pile, or during factory milling processes, has become a topic of major concern in recent years, particularly in those areas of the world where mechanical harvesting of billeted sugar cane has increased dramatically. Little work has been accomplished on accurately elucidating the relative contributions of microbial, enzymic, and chemical reactions to sucrose lossses on cane deterioration at ambient temperatures. This is partly because inaccurate pol measurements have been too frequently used to evaluate sucrose losses. This investigation was undertaken to determine the relative sources of cane sucrose losses by using laboratory tests to compare microbial, enzymic, and chemical deterioration of sucrose in factory cane juice. Heat (boiling temperature) and biocide treated juice, as well as untreated juice, were deteriorated at 27°C (to simulate factory ambient temperature) in an incubator across 71 hours (h). The biocide treated juice retained its dark brown color, fresh odor, initial pH and °Brix levels across 71 h. In strong contrast, after 71 h the untreated juice was light brown, had a strong alcohol odor and markedly lower pH and °Brix levels. The color of the heated juice only reduced after 23 h, and the juice was viscous after 71 h and had neither a fresh nor alcoholic odor. Sucrose, glucose, and fructose were analyzed using gas chromatography. Over the first 14 h of deterioration, 93.0% of sucrose losses were microbial, 5.7% enzymic and 1.3% were chemical (acid degradation). Ion chromatography with integrated pulsed amperometric detection (IC-IP AD) was used to simultaneously analyze for ethanol, mannitol, and oligosaccharides in deteriorated cane juice. The rate of formation of mannitol, produced from the reduction of fructose by mannitol dehydrogenase in dextran forming Leuconostoc bacteria, was much higher than associated oligosaccharides or ethanol formation. A further investigation of the use of mannitol as a sensitive indicator of future dextran related processing problems at the cane factory is warranted. Ethanol was shown not to be very useful as an indicator of Leuconostoc bacterial cane deterioration.
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