不同热处理工艺对牛乳中热敏感成分的影响

热处理是保证乳制品质量稳定和卫生安全的重要手段之一,牛乳在热处理过程中会发生美拉德反应、乳糖异构化和蛋白质变性等多种化学变化,且反应程度与热处理强度密切相关。文中以纯鲜生乳为材料,经巴氏、超巴氏和超高温瞬时杀菌(UHT)等热处理后,分析检测牛乳中主要热敏感成分的变化。结果表明:随着热处理强度的提高,牛乳中的糠氨酸含量呈指数关系增加,纤溶酶活则逐渐下降;热处理强度不同导致乳清蛋白各组分的变性程度也不同,其中β-LgB和BSA对热最敏感,β-LgA其次,α-La的耐热性最强;热处理温度越高,时间越长,牛乳中VB1和VB6的损失率也就越高。根据牛乳中热敏感成分含量或活性在热处理过程中的的变化规律,可以将糠氨酸、α-乳白蛋白和纤溶酶活等作为牛奶受热程度的指示物,从而更好的指导实际生产和维护消费者权益。

Effects of Heat Treatment Processing on the Heat-sensitive Components in Milk

Thermal treatment is a key procedure in dairy products preparation to ensure the products safety.During the heat processing,a variety of chemical reactions occurred,such as Maillard reaction,lactose isomerization and protein denaturation,which are all closely related to the heat treatment intensity.The objective of the present study is to evaluate the effect of different thermal treatments on the heat-sensitive components in milk by comparing the heat damage between raw milk,pasteurization milk,ultra-pasteurization milk and UHT milk.In the raw milk,the furosine contents increased with increased heat treatment strength,while plasmin activity decreased.The thermal treatment caused whey protein denaturaed,in which β-LgB and BSA were more sensitive to heat treatment and the α-La was heat resistance;the content of vitamin B1 and B2 decreased as the improvement of thermal treatment.We can determine the content or activity of the furosine,α-La and plasmin to be used as the heat indicators in order to identify different heat treatment of milk.This will help dairy products manufacturing and protect the interests of consumers.