氨基酸折算法计算婴幼儿配方粉中乳清蛋白含量方法的评估

目的评价以氨基酸折算法计算婴幼儿配方粉中乳清蛋白含量的方法。方法本实验使用自配的流动相,采用酸水解氨基酸自动分析仪测定婴幼儿配方粉中氨基酸含量,再根据乳清蛋白中天冬氨酸/天冬酰胺、丙氨酸、苯丙氨酸和脯氨酸4种特征氨基酸含量的经验公式折算出婴幼儿配方粉中乳清蛋白占总蛋白的百分比。结果对我国市售多种品牌的婴幼儿配方粉中的水解氨基酸进行了检测,再计算出乳清蛋白含量,发现仅1阶段乳基婴儿配方粉基本符合大于60%的国标规定。结论该氨基酸折算法对婴幼儿配方粉中乳清蛋白含量的定量研究具有参考价值,但对掺有大豆蛋白的产品无法进行准确测定。

Evaluation of amino acid conversion method for calculating whey protein content in infant formula powder

Objective To evaluate amino acid conversion method for calculating the whey protein content in infant formula powder. Methods Using the self-made mobile phase, amino acid content in infant formula powder was determined by automatic amino acid analyzer of acid hydrolysis. The percentage of whey protein in total protein in infant formula powder was converted according to the empirical formula of the content of four characteristic amino acids, including asparagine/aspartic acid, alanine, phenylalanine, and proline in whey protein. Results Hydrolyzed amino acids in infant formula powder from a variety of commercially available brands were detected, and then the whey protein content was calculated. It was found that only one stage of milk-based infant formula powder reached the national standard of above 60%. Conclusion The amino acid conversion method provided reference values for the quantitative research of whey protein content in infant formula powder, but it could not provide accurate detection for products mixed with soybean protein.