Research On The Effect Of Co-60 Gamma Irradiation On Brown Rice During Storage At Low Temperature

China is a big consumer of rice, rice storage related to national security and social stability. Irradiation used in food storage and processing areas widely. This study analyzed brown rice irradiated by 60Co-y then storage for a period of one and a half years, during storage, the microstructure,pasting quality,food quality, physical and chemical quality and lipids changes. The purpose of this article is to clarify the change mechanism of quality induced by 60Co-y irradiation on storage brown rice and provide a theoretical basis for determining suitable irradiation dose level and technical methods for rice storage.After the harvest of rice cereal, shelling to brown rice and stored in plastic film samples bags, then irradiated at 0.2,0.5,1.0 and 2.0 kGy. After measure the initial index,brown rice stored at 15±0.5℃ for one year and a half, qualities measured every three months;by measuring the indicators,we analyzes the relationship between the various macroeconomic indicators and the relationship between macroeconomic indicators and microstructure of brown rice. The main purpose is study the effects of different doses of irradiation and storage time on the brown rice. The main conclusions are as follows:1. Brown rice paste parameter values (peak viscosity, through viscosity, breakdown values, setback and final viscosity) decrease with the irradiation dose increasing, while the pasting temperature increases with dose increasing,this indicate that starch gel process softer,cold paste stability improved during pasting,the rice is more resistant to cooking,as a result,the quality of the cooking rice improved.The hardness of cooked rice increased with storage time; 0.5 kGy of irradiation dose reduced the hardness of cooking rice significantly and rice get softer texture.2. Irradiation modified the starch structure, the starch granules become smaller,more water can penetrate into starch when cooking rice,the surface area of hydration increased during cooking, rice texture becomes softer under the same conditions,so the hardness decreased significantly (P<0.05) when irradiation dose up to 0.5kGy, the tasting quality of rice improved.3. After irradiated by 1.0 kGy and 2.0 kGy, the surface color of rice becomes yellow (b-value increased significantly), so the sensory scores decreased significantly. The lightness value decreased with irradiation dose increase,so the color score in sensory decreased significantly. Tthe aerobic bacterial count of brown rice irradiated at different dose reach a significant level (P<0.01). After 2.0 kGy of irradiation treatment of brown rice. The TBA value of brown rice increased significantly (P <0.05), cooking rice has dislike flavor. The solubility and expansive force of rice increased with the irradiation dose increase.The amylose content increased with the increase of irradiation dose. Gamma irrdiation had no significant effect on the fatty acid of brown rice. Gamma irradiation treatment had no significant effect on the fat content and fatty acids accounted of brown rice (P> 0.05).