Effect of gamma irradiation on microbial load, physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill)

Abstract

Gamma irradiation is highly effective in inactivating microorganisms in various foods and offers a safe alternative method of food decontamination. In the present study, soybeans (Glycine max L. Merrill) were treated with 0, 1.0, 3.0, 5.0 and 10.0KGy of gamma irradiation. Microbial populations on soybeans, isoflavone, tocopherol contents, raffinose family oligosaccharides, color and sensory properties were evaluated as a function of irradiation dose. The results indicated that gamma irradiation reduced aerobic bacterial and fungal load. Irradiation at the doses applied did not cause any significant change (p>0.05) in the contents of isoflavone of soybeans, but decreased tocopherol contents. The content of key flatulence-producing raffinose family oligosaccharides in irradiated soybeans (10.0kGy) decreased by 82.1% compared to the control. Sensory analysis showed that the odor of the soybeans was organoleptically acceptable at doses up to 5.0kGy and no significant differences were observed between irradiated and nonirradiated samples in flavor, texture and color after irradiation.