Irradiation decontamination of soy protein flour

This paper reported decontaminative effects of irradiation on the soy protein flour quality, including main nutrient components, sensitivity of urea enzyme and sensory index. The results show that the irradiation treatment is very effective in eliminating microorganism in soy protein flour. The higher the dose was, the more microorganisms were eliminated. At least 53% microorganisms were eliminated at 2.0 kGy irradiation. Eliminating ratios of 95%, 97% and 100% were obtained at applied doses 4.0, 6.0 and 8.0 kGy, respectively. The content of protein, crude fiber, total sugar and amino acid (except Leu) and urea enzyme would not vary much in the ranged of 2 to 8kGy. But the content of crude fat and lecithin in irradiated soy protein flour is significant different (at 0.01 level), and the content of isoflavone significantly decreased (at 0.05 level). Irradiation will not change the sensory index of soy protein flour much when irradiation dose is lower than 6.0 kGy. It was concluded that the optimal dose for bacteria decontamination of soy protein flour is in the range of 3.0 ∼ 5.0 kGy for the sake of various quality factors. (authors)