Evaluation of Genistin and Genistein Contents in Soybean Varieties and Soy Protein Concentrate Prepared with 3 Basic Methods

The contents of genistein and its β-glucoside form, genistin, in 13 soybean varieties were determined. Soybean variety (Var-1) with high genistein and genistin contents (0.019 mg/g and 0.420 mg/g) was used to evaluate the 3 basic soy protein concentrate (SPC) production methods (acid, alcohol, and hot-water leach) for genistin and genistein retention on a total weight basis. The acid leach method gave the highest total genistin + genistein content (0.742 mg/g) compared to SPCs prepared with the hot-water leach method (0.671 mg/g), and the alcohol leach method (0.070 mg/g). The acid leach, hot-water leach and alcohol leach methods had 20.3%, 24.2%, and 91.2% losses of total genistin + genistein, respectively.