Cereal Chem 57:356 - 360.  |  VIEW ARTICLE
Changes in Oligosaccharides During Germination and Cooking of Black Gram and Fermentation of Black Gram/Rice Blend.

N. R. Reddy and D. K. Salunkhe. Copyright 1980 by the American Association of Cereal Chemists, Inc. 

The oligosaccharides of the raffinose family of sugars account for 61% of total sugars in black gram seeds and cotyledons. The black gram seeds studied had 3.4% verbascose, 0.9% stachyose, a trace of raffinose, and 1.5% sucrose, whereas the black gram cotyledons contained 4.0% verbascose, 0.7% stachyose, a trace of raffinose, and 1.5% sucrose on a dry weight basis. Germination of black gram seeds for 48 hr resulted in complete disappearance of verbascose, stachyose, and raffinose; the sucrose content was unchanged after 24 hr of germination. Increased alpha-galactosidase activity was observed during the first 48 hr of germination and throughout the 45-hr fermentations of black gram/rice and of black gram blends. Cooking for 40 min at 10 psi (116 C) caused a decrease in the oligosaccharide content of black gram cotyledons. Polished Texas long-grain rice did not contain the verbascose, stachyose, and raffinose but had a trace of sucrose. Fermentation of black gram/rice and of black gram blends for 45 hr decreased the original oligosaccharides to 28 and 71%, respectively. Steaming of batter made from black gram/rice blend fermented for 20 hr produced an acceptable product, Idli, that contained about 1.0% verbascose and 0.2% stachyose, representing 44% of the total sugars.