Isoflavone, γ-aminobutyric acid contents and antioxidant activities are significantly increased during germination of three Chinese soybean cultivars

The changes in isoflavone and γ-aminobutyric (GABA) contents and antioxidant activity of germinated soybean seeds were investigated. Three Chinese soybean cultivars (ZH 13, 30 and 42) released for high yield and protein content were evaluated. The results showed that the total isoflavone contents at peak level were 86.3, 81.0, and 42.3% higher than that of the un-germinated control for ZH 42, 13 and 30, respectively. GABA content of ZH 13 in particular was a statistically significant 36.7-fold increase in day 5 germinated soybeans as compared to un-germinated soybean. Such increases also led to significantly elevated antioxidant activities. Moreover, germination can significantly suppress IL-8 expression in Caco-2 cells by ZH 13 extract (P < 0.05) without cell apoptosis. Current results suggest that ZH 13 soybean is a cultivar that can be used to develop nutritional and functional foods with important health benefits.