Evaluation of the Smri Juice Colour Analysis Methods and Laboratory Clarification Tests

Raw sugar colour is an increasing sugar quality concern, not because of a decline in the quality of South African very high pol raws but rather due to rapid improvements in the raw house colours in the rest of the world. Technically, raw sugar with lower colour has direct implications for the refiner’s effort and cost of processing that sugar. Enormous benefits could be derived if colourants could either be prevented from entering the factory or be removed early in the process, e.g. during clarification where insoluble impurities are already being settled out. The method for analysing juice colours in South Africa is based on the ICUMSA methods for sugar and molasses colours. This method was evaluated on both mixed juice and clear juice. Once repeatability limits were established, the SMRI laboratory clarification settling test could be evaluated for reproducibility in terms of colour changes. It was also ascertained that the effect of freezing of the mixed juice on the analysis and on the clarification procedure was negligible for at least six weeks of freezing.