乳粉及乳制品中酪蛋白含量及产地关联性的分析

Casein Content in Milk Product and Their Correlation of Production Origin

目的:考察不同产地、不同类型乳产品中αs1-、αs2-、β-、κ-酪蛋白四种亚型的含量比例及总含量,为临床营养师和食品监管机构提供科学依据。方法:采用新型质谱定量技术对106批次国内外乳原料及乳制品中酪蛋白四种亚型含量进行分析,通过合成特异性标准多肽,进行内标法定量。结果:国内外乳原料、婴幼儿配方乳粉、普通营养调制乳粉和液态乳中酪蛋白总含量平均值分别为14.79、3.47、12.66、1.95g/100g。中国国产以上四类乳产品中酪蛋白总含量平均值分别为15.08、4.17、11.66、2.06g/100g,除普通营养调制乳粉外,其余三类均高于本次分析国内外样本量的平均值。酪蛋白含量丰富的产品与优质奶源产地之间不存在完全正相关的关系。另外,本研究还发现了酪蛋白四种亚型之间的含量比例在不同类型乳产品中呈规律性分布。结论:酪蛋白作为乳产品中丰度最高的营养性蛋白,其总含量及亚型之间的比例可以作为指征乳产品优劣程度和食品检验的精准判断标准。

Objective To investigate the casein(αs1-、αs2-、β-、κ-)proportion and total content in different milk products from different product regions to provide scientific evidence for market supervision departments.Method As a modern protein quantification technique,mass spectrometry-absolute quantification method had been applied to 106 batches raw milk and milk product.A synthesized signature peptide as internal control for sample quantification.Result Fist,the overall average value of casein content in raw milk,infant milk powder,modulation powder and liquid milk producing both in China and overseas were 14.79g/100g,3.47g/100g,12.66g/100g,1.95g/100g,respectively.On the other hand,those four types of milk products inspected in Chinese domestic market were much higher than overall average value,except modulation powder.The casein content reflected the level of domestic market were 15.08g/100g,4.17g/100g,11.66g/100g,2.06g/100g,respectively.There was not the absolute correlation between high casein products and high milk production regions.Furthermore,the distribution rule of four types of casein in different milk products had been confirmed.Conclusion As the highest nutritional protein in milk,casein content and their proportion not only represent the quality of milk products to certain extent,but also supply accurate judgement criteria on food testing.