RELATIONSHIP BETWEEN JUICE PROPERTIES AND ASH IN SUGAR

An analysis of data from five mills located in the North Queensland, Burdekin and Bundaberg areas was carried out to produce quantitative relationships between the properties of first expressed juice and the percent ash in sugar. The purpose of this analysis was to provide criteria for assessing the quality of the cane supply for possible responses by cane breeders, growers and millers to high ash in sugar. By using regression analysis, equations were developed for both percent ash and ash/impurity ratio in sugar. The results show that both ash and ash/impurity in sugar increase with increases in conductivity/impurities and with decreases in impurities/pol in first expressed juice (FEJ). The percent impurities in FEJ correlated most strongly with ash levels in sugar. While ash in sugar increases with increasing impurities in sugar, ash/impurities decreases. The latter dependency may be due to partitioning of impurities. Although the same variables apply to the various mills, the specific relationship for a particular mill could not be applied to other mills. Statistically significant relationships were not obtained for all data sets. Where a statistically significant relationship was not achieved the sugar was produced over a limited period and the ranges for the juice properties were small. Validation of the relationships is required to establish whether they can be applied for prediction of ash in sugar and assessing cane quality.