Response of nutritional and functional composition, anti-nutritional factors and antioxidant activity in germinated soybean under UV-B radiation

The effects of germination under UV-B radiation on the nutritional and functional composition, anti-nutritional factors and antioxidant activity of germinated soybean were comprehensively investigated. Results showed that total sugar decreased by 16% and the free amino acids increased from 0.29 to 4.73 g/100 g during germination, while UV-B inhibited these changes. LTV-B increased Asp content, but reduced Glu content. Germination enhanced the level of saturated fatty acids and suppressed the proportion of unsaturated fatty acids, while UV-B further increased the linolenic acid and erucic acid contents. In addition, UV-B significantly elevated the contents of isoflavones (from 3325 to 8080 mu g/g), phenolic acids (from 24 to 104 mu g/g), vitamin C (from 21 to 194 mg/100 g), folate (from 783 to 1602 mu g/100 g), and chlorophyll contents (from 0.007 to 0.237 mg/g) during germination, respectively. Meanwhile, enhanced antioxidant activity and reduced anti-nutritional factors were also observed in the presence of UV-B. Principal component analysis indicated that changes in free amino acid, vitamin C and folate were highly correlated with antioxidant activity. Therefore, UV-B radiation during germination is an efficient protocol to enhance the nutritional and functional qualities of soybeans.