Manufacturing-Processing DEXTRANS AND DEXTRANASE

Information was sought on the cause, effects, and control of dextran in sugar manufacture in Jamaica. Storage experiments on manually harvested, burnt, whole-stalk cane revealed that Leuconostoc mesenteroides was the predominant spoilage organism. Its growth was accompanied by significant increases in dextran content and juice viscosity. However, these parameters. did not increase linearly with storage time. "Dextran" was frequently detected in fresh cane by the haze analysis technique but it was thought to differ from true dextran. Measurements of the occurrence and frequency distribution of dextran in factory mixed juice indicated that much of the cane was sour or stale and likely to cause processing difficulties. A small but significant correlation existed between L. mesenteroides count and dextran content of mixed juice (r = .320, p = .01). The viscosity of mill syrups was correlated with dextran content (r = .633, P = .01), but no correlation was observed between c-axis crystal elongation and dextr.an content of c-massecuites. Final molasses purity was correlated with dextran content of mixed juice in corresponding weeks (r = .557, P = .02), but this may have been due in part to a decline in cane quality. Treatment of mixed juice with dextranase significantly reduced the dextran content. At an enzyme concentration of 3 units/100 ml juice, 68.5% of the initial dextran was removed within 20 min at 40 C. Microbial amylases were less effective than dextranase. It was concluded that the harmful effects of dextran on sugar manufacture may be successfully eliminated by treatment with dextranase, either alone or with other enzymes.