中文摘要：黄曲霉及随之而来的黄曲霉毒素污染花生是全球最严重的安全问题之一。水活度(a(w))及温度是储存时真菌生长及黄曲霉毒素产生的限制因素。为优化实际储存参数，本研究探索了a(w)(0.85-0.99)、温度(15-42摄氏度)对带壳花生真菌生长、黄曲霉毒素产生及黄曲霉毒素生物合成及调节基因表达的作用。从食品安全的角度，该项研究的结果可用于优化某些食品工艺并制定预防控制粮食（如花生、玉米和水稻）及其制品中这些致癌的天然代谢物的策略。
外文摘要：The contamination of peanuts with Aspergillus flavus and subsequent aflatoxins is considered to be one of the most serious safety problems in the world. Water activity (a(w)) and temperature are limiting factors for fungal growth and aflatoxins production during storage. To optimize the practical storage parameter, the effect of a(w) (0.85-0.99) and temperature (15-42 degrees C) on fungal growth, aflatoxin production and the expression of aflatoxin biosynthetic and regulatory genes in shelled peanuts was investigated. A. flavus grew at a lower rate when temperature <= 20 degrees C or a(w) <= 0.85. For the growth of A. flavus in shelled peanuts, the optimum conditions were a(w) was 0.98, and the optimum temperature was 37 degrees C. The maximum amount of AFB(1) in peanuts was obtained at 28 degrees C and a(w) 0.96. Real-time analysis showed that 16 of 25 genes had highest expression levels at 28 degrees C under a(w) 0.92, while 9 genes had highest expression levels at 37 degrees C under a(w) 0.92. Compared with 37 degrees C, all aflatoxin biosynthetic pathway genes were down regulated at 42 degrees C. All the pathway genes and laeA were up-expressed at aw of 0.96 under 28 degrees C, compared to a(w) 0.99. Furthermore, there was a good positive correlation between the ratio of aflS/afIR and AFB(1) production. The expression of laeA was also positively correlated with AFB(1) production while the expression of brlA was correlated with the A. flavus growth. The results of this study suggest that AFB(1) production in peanut kernels can occur over a wider range of a(w) x temperatures levels compared to formula media and peanut media. Previous studies have showed that AFB(1) could not be produced on formula media at 37 degrees C without the expression of most aflatoxin structural genes. But, in the un-autoclaved shelled peanuts, high concentration of AFB(1) was produced at 37 degrees C with up-regulation of some aflatoxin biosynthetic genes. From a food safety point of view, the results can be used to optimize certain food technological processes and develop prevention strategies to control such carcinogenic natural metabolites in grains (such as peanuts, maize and rice) and derived products.
外文关键词：Molds；Aspergillus flavus；Aflatoxin；Water activity；Temperature
作者：Liu, X；Guan, XL；Xing, FG；Lv, C；Dai, XF；Liu, Y；AF Liu, Xiao；Guan, Xuanli；Xing, Fuguo；Lv, Cong；Dai, Xiaofeng；Liu, Yang
作者单位：Chinese Acad Agr Sci
期刊名称：FOOD CONTROL
期刊影响因子：3.388
出版年份：2017
出版刊次：-
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