Bioactivities of fractions obtained from green gram (Vigna radiata) milled by-products

Green gram as dhal (dehusked split cotyledons) is a common food material in India. During milling of green gram into dhal, 18% of the grain becomes by-product. The by-product was separated into the husk, the germ, the plumule rich fraction (PRF) and the aleurone rich fraction by sieving and air classification. Polyphenols, flavonoids, tannins, carotenoids and chlorophyll contents were the highest in the husks followed by the PRF. The husk and the PRF showed antioxidant activity with IC50 values of 12 and 23 µg for DPPH; and 17 and 25 µg for ABTS˙+ scavenging activities, respectively. The husk and the PRF showed IC50 values of 0.3 and 0.3 mg for α-amylase inhibition; 0.2 and 0.3 mg for α-glucosidase inhibition; and 2 and 3 µg for oxidative DNA damage protection, respectively. Gallic acid, ferulic acid, sinapic acid, vitexin and isovitexin were the major bioactive compounds in various fractions, and these compounds were found to be the highest in the husks followed by the PRF. Thus, the present study suggests that green gram milled by-products may contain useful nutraceutical compounds.