Enrichment of Genistein in Soy Protein Concentrate with b-glucosidase

Genistein has been reported to have the most potent anticarcinogenic effect among isoflavones. Conversion of genistin in the glucoside form to genistein in the aglucone form by a b-glucosidase enzyme hydrolytic activity during soy protein concentrate (SPC) preparation was evaluated. The optimum conditions for the conversion of genistin to genistein were pH 5.0, 50 °C incubation temperature, 2 units of enzyme/g of soy flour, 1 h incubation period, and 1:10 (w/v) defatted soy flour to water ratio. Under these conditions, 1.214 mg/g genistein were obtained in SPC and is significantly (p < 0.05) higher than the genistein content in SPC prepared under similar conditions without enzyme addition (0.845 mg/g).