a-Galactosidase was immobilized in j-carrageenan. The optimum pH of the soluble enzyme and immobilized enzyme was 4.8. The optimum temperature of the soluble enzyme was 50°C and that of the immobilized enzyme was increased to 53°C. The immobilized enzyme was used in batch, repeated batch, and in the continuous mode to degrade the raffinose family sugars present in soymilk. Two hours incubation with free and immobilized a-galactosidase resulted in 88 and 75% reduction in raffinose family oligosaccharides in soymilk respectively. In the repeated batch, 61% reduction was obtained in the fourth cycle. A fluidized bed reactor was designed to treat soymilk continuously. The performance of immobilized a-galactosidase was also tested in a fluidized bed reactor at different flow rates and 92% reduction of raffinose family oligosaccharides in soymilk was obtained at 25 ml h )1 flow rate. The study revealed that immobilized a-galactosidase in continuous mode is efficient in reducing the oligosaccharides present in the soymilk.

The oligosaccharide content was determined in 12 different cultivars of black gram. The effect of various treatments such as soaking, cooking, and enzyme treatment on the raffinose family oligosaccharides of dry seeds and flour was studied. Ajugose, a higher oligosaccharide (DP 6) found in trace quantities in seeds, was shown in black gram by HPLC. The percent reduction of raffinose, stachyose, verbascose, and ajugose after soaking for 16 hr was 41.66%, 47.61%, 28.48%, and 26.82%, respectively in Local-I variety and 43.75%, 20.58%, 23.60%, and 15.88%, respectively in Local-II variety. Cooking for 60 min resulted in decrease of 100% for raffinose, 76.19% for stachyose, 36.39% for verbascose, and 60.97% for ajugose in Local-I variety and 100% for raffinose, 55.88% for stachyose, 48.52% for verbascose, and 56.07% for ajugose in Local-II variety. Thin layer chromatographic analysis of 3 hr enzyme-treated samples revealed almost complete hydrolysis of raffinose family of oligosaccharides. Among the different methods employed, enzyme treatment was found to be the most effective for removing alpha-galactosides in black gram.

No abstract