毛细管电泳法对乳及乳制品中乳源蛋白的研究

采用毛细管电泳方法对原料乳、市售鲜奶、不同厂家的巴氏灭菌乳、不同厂家和产地超高温灭菌乳(UHT)、调味乳、乳酸饮料、复原乳、酸奶、奶粉中蛋白成分进行检测。选择聚乙烯醇涂层毛细管,采用柠檬酸缓冲体系,在紫外检测214nm、分离电压20kV条件下对乳及乳制品中的α一乳白蛋白(α-La)、β一乳球蛋白(β-Lg)、α-酪蛋白(α-CN)、β-酪蛋白(β-CN)和k-酪蛋白(k-CN)进行分离测定。结果表明:五种蛋白的含量在原料乳(巴氏灭菌乳、市售鲜奶)、UHT乳、酸奶、调味乳、乳酸饮料、复原乳中依次降低,而UHT乳含量随保质期的增加而减少,奶粉中蛋白质含量因其适应人群而有差异。乳及乳制品中蛋白质的含量与其存在形式、产地及加工工艺相关。

Study on milk proteins in milk and milk products by capillary electrophoresis

The contents of milk protein were determined by capillary electrophoresis in raw milk,fresh milk in market,pasteurized milk from different plants,ultra-high temperature(UHT)milk from different plants and fields,sterilized flavor milk,lactic acid beverage,reconstituted milk,sour milk and milk powder.The proteins of α-La,β-Lg,α-CN,β-CN and k-CN were separated and analyzed by using polyvinyl alcohol coated capillary column and citric acid buffer solution with running voltage of 20kV and UV detection at 214nm.The results showed that the contents of five proteins decreased systematically in raw milk(fresh milk,pasteurized milk),UHT milk,sour milk,sterilized flavor milk,lactic acid beverage and reconstituted milk.And the contents of proteins in UHT milk decreased with the increase of their shelf life,the contents of proteins was changed with appropriate population.The contents of proteins in milk and milk products were related with their existing form,producing area and processing technology.