Characterization and Comparison of Antioxidant Properties and Bioactive Components of Virginia Soybeans

Abstract

Nine Virginia soybeans grown in a single location were evaluated and compared for their antioxidant properties and isoflavone profiles. The total phenolic content (TPC) in the soybean extracts was significantly different among different genotypes. The V01-4937, V03-1144, and MFS-511 soybeans had the highest TPC values of 3.89, 3.63, and 3.53 mg of gallic acid equiv/g of seeds, respectively. The isoflavone composition was also different among the different soybean varieties. Malonylgenistin was the major isoflavone in all soybean seeds, accounting for 75-83% of the total measured isoflavones. The V01-4937 variety had the highest total isoflavones and malonylgenistin content followed by the V03-5794. The antioxidant activities of the soybean extracts were also significantly different. V01-4937 and Teejay showed the strongest ORAC values, which were 70% higher than that of the V00-3493 soybean, which had the lowest ORAC value (115.7 micromol of Trolox equiv/g of seeds). However, their ORAC values were correlated with neither TPC nor total isoflavone content. The MFS-511, V01-4937, and Teejay soybeans had the highest DPPH radical scavenging activities of 4.94, 4.78, and 4.64 micromol of Trolox equiv/g of seeds. Overall, the V01-4937 soybean stood out among the tested Virginia soybeans with regard to having the highest TPC, ORAC value, and isoflavone content as well as the second highest DPPH scavenging activity.