Effects of 60Co γ-irradiation on the Sterilization and Quality of Arachis hypogaea.L

Abstract:

To reduce microbial contamination in peanut, the bactericidal effect of 60Co γ-irradiation on the peanuts and the effects of 60Co γ-irradiation on the physicochemical properties and the texture characteristics and lipoxygenase of peanut were investigated. The results showed that 60Co γ-irradiation could significantly reduce the microbial content of peanut in a dose-dependent manner. The disinfection rates of total bacterial count, mold and yeast were 94.58% and 95.63%, respectively. The decimal reduction dose (D10) values of total bacterial count, mold and yeast were 2.33 kGy and 1.10 kGy, respectively. The sensory evaluation scores decreased with increasing irradiation doses, the sensory quality of peanuts was acceptable at the irradiation doses 1.5 kGy. At the range of dose of 0.00~4.50 kGy, irradiation had no significant effect on the moisture, fat, protein and fatty acids of peanuts, whereas, there was a significant decrease in the amount of coarse fiber when the irradiation dose was more than 1.50 kGy. Irradiation treatment could increase the hardness of peanuts to a certain extent, but had no obvious effect on the cohesiveness, elasticity, adhesiveness and chewiness of peanut. In addition, irradiation had no significant effect on lipoxygenase of peanuts. Therefore, when the dose of 60Co γ-irradiation dose was not more than 1.50 kGy, it could effectively kill the microbes in peanut and keep the maximal original edible quality of peanuts.