非变性聚丙烯酰胺凝胶电泳检测新疆特种乳中掺加的牛乳

Detection of Xinjiang special milk adulteration cow milk by native polyacrylamide gel electrophoresis

新疆特种乳资源丰富,具有重要的商业价值。近年来乳制品掺假问题时有发生,准确鉴别特种乳中乳源动物成分,防止牛乳掺假具有重要的意义。本研究采用非变性聚丙烯酰胺凝胶电泳(native-PAGE)对驼乳、马乳、驴乳、山羊乳与牛乳等特种乳的乳清蛋白及酪蛋白进行乳间差异性分析,建立基于牛乳特征蛋白质多态性的检测方法,并研究不同热处理工艺对检测方法稳定性、灵敏度的影响。结果表明,牛β-乳球蛋白可作为特种乳中掺加牛乳的检测靶标,热处理会使样品中蛋白质发生变性,导致掺加牛乳检出限的升高。基于牛β-乳球蛋白的条带强度与牛乳掺加百分比建立回归方程,相关系数为0.9779~0.9998,定量范围在5%~100%之间。本研究为新疆特种乳中掺加牛乳的检测,提供了一种准确、灵敏和经济的方法。

Xinjiang special milk is resource-rich,with high commercial value.In recent years,the adulteration problem of dairy products has occurred constantly.For preventing adulteration,accurate identification of animal-origin components in milk is significant.In this study,based on the analysis of differences of whey protein and casein in bovine milk and four special milks(camel,horse,donkey and goat milk)using native-PAGE,we established a detection method based on polymorphisms of characteristic bovine milk protein and studied stability and sensitivity of the method under different heat treatment conditions.Results showed that a regression equation was established based on the band intensity of bovineβ-lactoglobulin which found as the characteristic protein and the percentage of milk adulteration.The correlation coefficient was 0.9779-0.9998,and the quantitative ranged between 5%and 100%.Heat treatment resulted in increased LOD.This study provided an economical method for detection of the adulterated cow milk.