Factors affecting the colour formation and its estimation of clarified cane juice
1993
Yuwapha Wirojsakulchai
Factors, pH and incubation time that affecting colour formation of clarified cane juice were investigated. Clarified cane juice of pH 8, 9 and 10 were incubated at 100 deg C for 300 minutes. The increasing of lactic acid concentration and dark colour compounds of clarified cane juice contributed to the decreasing of pH and sucrose concentration. Moreover, the higher pH and longer incubation time promoted higher content of colour compounds in clarified cane juice. Colour values of clarified cane juice of pH 8, 9 and 10 were detected as 2345.58, 7329.44 and 11434.31 ICUMSA units respectively and the average rate constants of colour formations were 1.72/(exp.1), 2.38/(exp.1) and 1.02/(exp.1)/min respectively. Incubated clarified cane juice and molasses from 42 factories were fractionated by Sephadex G-25 gel filtration chromatography. It was found that gel filtration chromatograms of clarified cane juice were similar to that of caramel products and alkaline degradation products of glucose. Gel filtration chromatograms of molasses were similar to that of maillard products, caramels and alkaline degradation products of glucose. Absorption spectrums of incubated clarified cane juice and molasses were scanned at wavelength 200-500 nm. The lambda max was 243 nm which was the character of initial of thermal degradation, presence of carbonyl groups with one or more conjugated double bonds.
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