| The temperature and moisture soybean might encounter in the process of transportationand storage was simulated. The influence of storage conditions on soybean quality, thechanges of total soybean mold, as well as the soybean oil and meal quality changes wasstudied. Different degree of mildew soybean (storage0,10,30,50days) was irradiated with60Co (0kGy、5kGy、10kGy、20kGy、30kGy), the effect of irradiation on mold inhibitory, oilcontent and quality, protein content and quality was investigated. The results showed that:1. In the process of storing the content of crude fat and crude protein had no obviouschanges, total number of mold increased, Moisture content10.58%of soybeans did notappear mildew grain during storage, acid value, peroxide value, the proportion of unsaturatedfatty acid and KOH of soybean meal protein solubility had no obvious changes; moisturecontent15.23%of soybean appeared mildew grain on the28th day during storage, acid value,peroxide value increased, unsaturated fatty acid ratio and the soybean meal protein solubilityin KOH decreased; Moisture content20.17%of soybeans appeared mildew grain on the14thday during storage, acid value, peroxide value increased, unsaturated fatty acid ratio and thesoybean meal protein solubility in KOH decreased.2. The total number of mold in the mildew soybean was significantly reduced afterirradiation. More than99%of the mold of all the samples was killed after10kGy irradiation.Oil content in soybean and mildew soybean didn’t have obvious change after the irradiationof5kGy,10kGy, and20kGy, but increased slightly after the irradiation of30kGy, the oilcontent in mildew soybean didn’t have obvious change after the irradiation of5kGy,10kGy,20kGy and30kGy. Acid value of nomal soybean oil didn’t change obviously after irradiation,but acid value of mildew soybean oil increasesed after irradiation. Peroxide value andcarbonyl value of normal soybean and mildew soybean increased, iodine value and theoxidation induction time decreased, and the proportion of unsaturated fatty acids, vitamin Econtent in oil was reduced after irradiation.3. The content of protein in soybean didn’t change obviously, and the content of amino acids decreased sligtly after irradiation. Water and oil absorption capacity, emulsification,emulsifying stability of protein concentrate changed obviously, nitrogen solubility indexdecreased, and in vitro digestibility didn’t change obviously after irradiation. SDS-PAGE andFT-IR analysis showed that the structure of protein changed obviously after irradiation, partof the protein aggregation, and the proportion of various secondary structure changedobviously. After the irradiation of5kGy, the isoflavones content increased, but decreased withthe increase of irradiation does. |
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