2016 Volume 51 Issue 1 Pages 11-16
Soybeans are an inexpensive and nutritious food with strong radical-scavenging activity, believed to reduce the risk of developing diseases associated with the generation of reactive oxygen species and inhibit the progression of such diseases. Although gamma irradiation of soybeans improves their physical characteristics without adversely affecting flavor, the specific radical-scavenging activity of irradiated soybeans has not been well studied. Here, the scavenging activity of soybean water extracts for individual radical species was investigated by electron spin resonance (ESR) spin trapping. Singlet oxygen-scavenging activity increased, whereas superoxide radical-scavenging activity decreased with increasing radiation dose; however, the hydroxyl and alkoxyl radical-scavenging activity of irradiated and non-irradiated soybeans did not differ significantly. The oxygen-radical absorbance capacity of irradiated and non-irradiated soybeans also did not differ significantly. Our findings demonstrate that gamma-irradiation affects the superoxide radical and singlet oxygen-scavenging activity of soybean water extracts.