Tannin contents and protein digestibility of black grams (Vigna mungo) after soaking and cooking

The objective of this research was to ascertain the effects of soaking black grams (Cultivar AARI-5732)in different salt solutions at different temperatures and different timeperiods, and different methods of cooking on the tannin content and proteindigestibility. Tannin content of black grams was reduced to variousextents by soaking at 30^° and 100 ^°C for different timeperiods. However, soaking at 100 ^°C increased the rate ofextraction and reduced the extraction time of tannins. Soaking black gramsin water at 100 ^°C reduced tannins by 22.14% in 45 minuteswhereas about 2.5 times more tannin was reduced after soaking in sodiumbicarbonate solution with or without sodium chloride. Maximumimprovement in protein digestibility was also observed after soaking blackgrams in sodium bicarbonate solution. Tannin contents were furtherreduced along with improvement in protein digestibility as a result ofcooking.