Degradation of sucrose during sugar processing - II. Storage study of refinery liquors at specific processing steps

The levels of sucrose, D-glucose, D-fructose and oligosaccharides were moni tored at a number of the steps involved in cane sugar processing at the Mar seilles Saint-Louis Sucre refinery. This was carried out using an accurate analytical method for carbohydrate determination (High-Performance Anion-Ex change chromatography with Pulsed Amperometric Detection, HPAE-PAD). A seri es of recovery house products were analysed with respect to temperature, pH , Brix, and levels of the listed sugars at the weekly shut down on early Sa turday, and at start up of the refinery early on Monday. They were also inc ubated for 96 h at the sampling temperature and at various initial pH value s in order to determine the optimum conditions for stability during storage . When the initial pH of the refinery liquors was about 6 - 6.5, they were found to be relatively stable, whereas an increase in the initial storage p H from 7 to 8.5 resulted in a slight decrease in the invert sugar content a nd subsequent acidification of the liquor, but no significant change in the sucrose level occurred during the 96-h incubation period. Both first and s econd strike syrups, i.e. syrups 1 and 2, the initial pH values of which ra nged from 7 to 8, were also found to be stable during this incubation perio d. In contrast, the clear liquor resulting from the decolorization step using an ion exchange resin, which had an initial pH higher than 8, rapidly under went degradation when stored at 85 degrees C for the 96 h trial period.