常温储存和干热处理对豆粕蛋白质氧化的影响

研究常温储存和干热处理对豆粕中蛋白质氧化的影响。取新鲜豆粕200 g装入自封袋,置于室温下保存不同时间(1、10、20、30和60 d);另取豆粕20 g于烘箱中100℃加热不同时间(0、1、2、4和8 h),测定分析2种处理方式对豆粕中的蛋白质羰基、巯基、总巯基基团及氨基酸含量的影响。结果表明,与新鲜豆粕(对照)相比,室温储存和干热处理不同时间后蛋白质羰基含量均显著增加(P0.05);随储存和干热处理时间的增加,豆粕蛋白质巯基和总巯基基团含量均逐渐降低,蛋白质巯基被氧化成非二硫键的含硫化合物,导致蛋白质巯基和总巯基与二硫键含量均降低;随加热时间的延长豆粕中苏氨酸、酪氨酸、赖氨酸及组氨酸含量在数值上逐渐降低。结果提示,蛋白质羰基、巯基及氨基酸含量的变化与蛋白质氧化密切相关,室温储存和干热处理均会导致豆粕中蛋白质发生氧化。

Effects of Storing and Heating on Protein Oxidation of Soybean Meal

Effects of storing and heating on protein oxidation of soybean meal were studied in this trial. 200 g fresh soybean meal was put into the zip-lock bag and stored at room temperature for different time (1, 10, 20, 30, and 60 d); besides, 20 g fresh soybean meal was put in an oven and heated at 100 °C for different time (0, 1, 2, 4, and 8 h), then the contents of protein carbonyl, sulfhydryl, total disulphide/sulphydryl groups, and amino acid of soybean meal were measured. The results showed that compared with the fresh soybean meal (control group), protein carbonyl of soybean meal were significantly increased by storage at room temperature or dry heat treatment for different time (P<0.05); protein sulfhydryl and total disulphide/sulphydryl groups of soybean meal decreased gradually with increased storage or heat time; protein sulfhydryl is oxidized to a non-disulfide bond sulfur compounds, leading to the decrease of the protein sulfhydryl and total disulphide/sulphydryl groups; the content of threonine, tyrosine, lysine and histidine of soybean meal decreased gradually with increased heat time. The results implied that the content of protein carbonyl, sulfhydryl, or amino acid is closely related to protein oxidation, and both storing at room temperature and heating will result in protein oxidation.