STARCH AND PROTEIN DIGESTIBILITY OF RICE BEAN (VIGNA-UMBELLATA) - EFFECTS OF DOMESTIC PROCESSING AND COOKING METHODS

The present investigation was conducted to study the in-vitro starch and protein digestibility of five high-yielding varieties (RB-4, RB-32, RB-37, RB-40 and RB-53) of rice bean (Vigna umbellata) and one variety each of green gram (K-851) and black gram (MT-9) as affected by various domestic processing and cooking methods which included soaking in tap water for 6, 12 and 18 h; sprouting for 40 and 60 h; ordinary cooking of unsoaked seeds and seeds soaked for 12 h; and autoclaving of unsoaked and soaked seeds. In-vitro starch digestibility (mg maltose released/g meal) and protein digestibility (per cent) of raw rice bean varied from 29·3 to 36·5, and 57·2 to 62·8, respectively. Both starch and protein digestibilities improved significantly on soaking, sprouting, cooking and autoclaving. There was a progressive and significant increase in starch and protein digestibility with successive increase in soaking and sprouting period. © 1990.