Time and temperature dependence of antioxidant activity from soybean seeds (Glycine max L. Merr.) during germination

Abstract

The influence of germination temperature and time on the antioxidant activity of soybean seeds was investigated. The MTB 760 soybean cultivar was germinated in dark condition at 22, 25, 28°C and ambient temperature 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 (AA) assayed by DPPH radical-scavenging activity in terms of IC50 of germinated soybean were determined. These values increased with the increase of germination time for all applied germination temperature and they tend to reach the maximum values after a period of 60 hours. Germination temperature also influenced these parameters and generally at 25°C they reached the highest values. The TPC, TFC, vitamin C and IC50 value of soybean seed germinated at 25°C for 60 hours were respectively 8.11 ± 0.03 mgGAE/g (DW); 6.45 ± 0.09 mgQE/g (DW); 12.80 ± 0.02 mg/g (DW) and 5.49 ± 0.03 mg/ml. The maximum content of α-tocopherol after 72 hours of germination was 0.247±0.004mg/g (DW). Correlation studies indicated significant negative correlation between the values of IC50 with TPC (r = -0.968).