Abstract: The supercritical CO2 extraction technology of isoflavones from soy bean meal was potimized by orthogonal test,and the antioxidant and antimicrobial activeties of the isoflavones were determined. The experimental results showed that the order of different factors affecting extraction rate is extraction temperature>operation pressure>amount of modifier >extraction time. The scavenged rates of ·OH and O2· are both above 50% when the concentrations of the isoflavones are 1.0 mg/ml and 1.2 mg/ml, respectively. The products can inhibit the growth of Staphylococcus aureus, Bacillus subtilis and B.licheniformis.

Key words: soy bean meal, genistein, supercritical fluid extraction, antioxidant activity, antimicrobial activity