IN VITRO DIGESTIBILITY OF STARCH EXTRACT AND FLOURS OF SOME UNDERUTILIZED LEGUMES

Abstract

Digestibility of underutilized legumes (African yam beans, Bambara groundnut, Fava beans, Limba beans and Pigeon pea) was studied and related to their proximate compositions, functional and rheological properties. The aim of this study is to extract starch and prepare flour from these selected legumes: African yam beans (Sphenostylis stenocarpa), bambara groundnut (Vigna subterranean L. Verdc), fava beans (Vicia fabas), limba beans (Phaseolus lunatus L) and pigeon pea (Cajanus cajan). The reducing sugar contents of the legume starch and flours ranged from 0.05-0.9 mg/g and 3.21-20.1 mg/g while the starch damage of starch and flour ranged from 0.81-10.7% and 2.8-8.6% respectively. The kinetc parameters Vmax/Km (catalytic preference) observed from Michealis Menten revealed pigeon pea flour and starch having the highest catalytic preference of 193, 0.159 min-1/mg/ml respectively were rapidly digested among the tuber flours and starches, fava pea flour and African yam bean starch having lowest Vmax/Km value of 38, 0.009 min-1/mg/ml respectively, indicating slow digestion rate among tuber flour and starches.