超巴氏杀菌对牛乳酪蛋白微观结构及凝聚性质的影响

Effect of Ultra-Pasteurization on Microstructure and Aggregation Properties of Casein from Bovine Milk

以未经过热处理以及两种常用巴氏杀菌(65℃30 min、72℃15 s)处理的牛乳为对照,探究超巴氏杀菌(121℃5 s)处理对牛乳中酪蛋白微观结构及凝聚性质的影响。粒径分析结果表明,超巴氏杀菌后酪蛋白粒径明显增加;透射电子显微镜和扫描电子显微镜的分析结果表明,超巴氏杀菌能够破坏酪蛋白胶束结构,产生大规模的交联和凝聚,但是凝聚作用能够使酪蛋白胶束呈现出更均一的状态;差示扫描量热法的分析结果表明,超巴氏杀菌处理的样品,其酪蛋白胶束的变性温度略高于未经过热处理的对照组,72℃15 s处理后的酪蛋白与其他3组相比热稳定性提高,其变性温度为99℃。

The effect of ultra-pasteurization(121℃/5 s)on the microstructure and aggregation properties of casein in milk was investigated in comparison with non-thermally treated milk and two commonly used pasteurization treatments(65℃/30 min,and 72℃/15 s).The results showed that the particle size of casein increased significantly after ultrapasteurization.Under transmission electron microscopy and scanning electron microscopy it was observed that ultrapasteurization could destroy the casein micelle structure and result in large-scale cross-linking and coagulation,but the coagulation could result in a more uniform state of casein micelles.Differential scanning calorimetry(DSC)analysis showed that the samples treated with ultra-pasteurization had a slightly higher denaturation temperature than the casein micelles without heat treatment.The thermal stability of casein was increased after the second pasteurization treatment when compared with the other treatments,and the denaturation temperature was 99℃.