Effects of gibberellic acid on the antioxidant activity of soybean seeds (Glycine max L. Merr.) during germination

Abstract

Changes in antioxidant compounds and antioxidant activity were studied in soybean seeds during germination applied gibberellic acid (GA₃) in soaking water. GA₃ concentrations in soaking water were set up as 0; 0.001; 0.01; 0.1; 1 and 10mg/L. The soaking process was carried out at ambient temperature for 12 hours prior germination. Soaked soybeans were germinated in dark condition, at 25oC for 0, 12, 23, 36, 48, 60 and 72 hours. The total phenolic content (TPC), total flavonoid content (TFC), vitamin C and a-tocopherol contents as well as antioxidant activity assayed by DPPH radical-scavenging activity in terms of IC50 of germinated soybean were determined. It was found that, the increase of germination time caused an increase the TPC, TFC, vitamin C, α-tocopherol as well as antioxidant activity and most of them tend to reach the maximum values after a period of 60 hours of germination. In addition, GA₃ has a profound effect upon the antioxidant potentials and it caused a significant enhancement in the production of antioxidant compounds when compared to control. GA₃ 1mg/L in soaking solution was proposed as optimum concentration to apply for soaking process.