The relationship between harvesting methods and dextran formation in sugarcane (Saccharum officinarum cv. Co 6806), and quality indices

Abstract

The effects of harvesting conditions on dextran deterioration, and indices indicating dextran in the juice were aimed to be studied for the sugarcane variety Co 6806. Therefore, sugarcane was harvested manually after plantation and two ratoons, before and after burning as well as with and without stalk chopping. Dextran formation in juice was measured 1 to 5 days after harvest, and correlated with pH, viscosity, Brix, colour, polarization, apparent purity and Australian commercial cane sugar (CCS). Harvesting methods alone did not explain cane deterioration, but it may be due to a combination of adverse cultivation, maturation, harvesting, environment and weather conditions. Still, burning and chopping may increase the risk of deterioration, and the maximum time from harvest to processing should not exceed 4 days. Increasing viscosity (R = 614, p<0.001), and decreasing pH to 6.1–6.4 (R = 0.807, p<0.001) correlated with dextran up to 893 ppm in Brix, while colour and Brix (total soluble solids) did not change, indicating dextran precipitation. Polarization correlated with CCS (R = 0.968, p<0.001). Among these indices, pH and CCS calculated from polarization were the best in predicting elevated dextran concentrations.