The Changes in Antioxidant Capacity of Soybean (Glycine max (L.) Merrill) and Mung Bean (Vigna radiate (L.)Wilczek) during Germination Process

Abstract

This study aim to determine effects of the germination time on the changes in antioxidant capacity of soybean (Glycine max (L.) Merrill) and mung bean (Vigna radiate (L.)). Antioxidant compounds, such as total polyphenol content (TPC), total flavonoids content (TFC), free radical scavenging capacities (DPPH), vitamin E content and vitamin C contents were studied. TPC were measured by Folin-Ciocalteu method. TFC were determine by the aluminum chloride colorimetric assay. The antioxidant capacities were determine using DPPH free radical scavenging method. Vitamin E content were measured base on reaction between α-tocopherol with ferric chloride. Vitamin C content were measured by iodine method. The result indicated that the changes in these bioactive compounds depended on the germination times. Germination of soybean provided a higher bioactive compounds than that of mung bean. Both TPC in soybean and mung bean increased sharply in the period 0-60h of germination, with 4.61 ± 0.03mg GAE/g dw at 60h for soybean and 3.59 ± 0.03mg GAE/g dw at 48h for mung bean. TFC were found to be 3.26 ± 0.15mg QE/g dw for soybean and 4.03 ± 0.02 mg QE/g dw for mung bean after 60h of germination. Besides, the DPPH values rose continuously during germination and reached a peaks of 76.20% at 60h of germination for soybean and 71.89% at 48h of germination for mung bean. The result also reported that vitamin C content and vitamin E content in two legumes increased during germination and the highest values at 72h (for soybean, 0.25 mg/g dw, 13.43± 0.21 mg/g dw and mung bean 0.19 ± 0.01 mg/g dw, 8.05 ± 0.24 mg/g dw, respectively). As so, the germination process in the period 60-72h affected the greatest enhancement in antioxidant compounds in soybean and mung bean.