Study on the storage of refinery liquors at different stages of sugar processing

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 mentioned sugars at the weekly shut down on early Saturday, and at start up of the refinery early on Monday. They were also incubated for 96h at the sampling temperature and at various initial pH val ues in order to determine the optimum stability conditions during storage. When the initial pH value of the refinery liquors was about 6-6.5, they wer e found to be relatively stable, whereas an increase in the initial storage pH value from 7 to 8.5 resulted in a slight decrease in the invert sugar c ontent and subsequent acidification of the liquor, but no significant chang e in the sucrose level during the 96-h incubation period. Both first and se cond strike syrups, i.e. syrups 1 and 2, the initial incubation pH value of which ranged from 7 to 8, were also found to be stable during this incubat ion period. In contrast, the clear liquor resulting from the decolourizatio n step using an ion exchange resin, the initial pH of which was higher than 8, rapidly underwent degradation when stored at 85 degrees C for 96h.