Comparison of Antioxidant Activities in Black Soybean Preparations Fermented with Various Microorganisms

Black soybeans [Glycine max (L.) Merrill] were fermented with various GRAS (generally recognized as safe) microorganisms, including Aspergillus sp., Bacillus sp. and yeast (Issatchenkia orientalis) at 30°C for 3 d. The antioxidant contents, including total phenolics and total flavonoids, and the antioxidant activities of 1,1-diphenyl-2-picrylhydrazine (DPPH), ferric reducing antioxidant power (FRAP) and HO.scavenging were analyzed in preparations of fermented black soybeans. Fermented cultures proved to yield significant levels of antioxidants compared with non-fermented cultures (P < 0.05). Fermented black soybean preparations possessed antioxidant activities could be attributed to the total phenolics and flavonoids present.