Submitted to: Sugar Tech
Publication Type: Review article
Publication Acceptance Date: 6/7/2009
Publication Date: 7/15/2009
Citation: Eggleston, G., Karr, J., Parris, A., Legendre, B. 2009. A rapid biochemical test to assess postharvest deterioration of sugarcane and milled juice. Sugar Tech. 11(2):189-195. Interpretive Summary: Currently, there is no reliable, sensitive, rapid, easy and inexpensive method to measure sugarcane deterioration in factory consignments. Mannitol formed by bacteria, is a very sensitive indicator of sugarcane deterioration that directly affects processing. A precise, accurate, rapid, simple and inexpensive method has been developed to measure mannitol at the factory. The method was validated for use across the processing season of a sugarcane factory in Louisiana. This quantitative method will allow sugarcane factory staff to screen individual consignments of cane, reject unsuitable ones for processing, and be used in a grower’s sugarcane payment formula.
Technical Abstract: The delivery of consignments of deteriorated sugarcane to factories can detrimentally affect multiple process units, and even lead to a factory shut-down. An enzymatic factory method was used to measure mannitol, a major degradation product of sugarcane Leuconostoc deterioration in the U.S., in press (consignment) and crusher juices collected across the 2004 processing season at a Louisiana factory. Weather conditions varied markedly across the season causing periods of the delivery of deteriorated sugarcane to the factory. A strong polynomial relationship existed between mannitol and haze dextran (R2=0.912) in press and crusher juices. Mannitol concentrations were usually higher than haze and monoclonal antibody dextran concentrations, which indicates (i) the usefulness and higher sensitivity of mannitol to better predict sugarcane deterioration from Leuconostoc and other bacteria than dextran, and (ii) the underestimation by sugar industry personnel of the relatively large amounts of mannitol present in deteriorated sugarcane that can affect processing. Greater than ~2500 ppm/%Brix mannitol in juice predicts downstream processing problems. The enzymatic method is quantitative and could be used in a sugarcane payment formula. Approximately > 300 ppm/%Brix haze in raw sugar indicated that the majority of the crystals were elongated. Approximately > 600 ppm/%Brix antibody dextran indicated when elongated crystals were predominant in the raw sugar. The enzymatic mannitol method underestimates mannitol in raw sugars.