重量法结合氨基酸分析法测定婴幼儿配方乳粉中小分子蛋白肽含量

Determination of small molecular peptides in infant formula milk powder by gravimetric method combined with amino acid analysis

目的:建立婴幼儿配方乳粉中小分子肽含量的定量分析方法。方法:分别采用凯氏定氮法、重量法、离子交换色谱等方法测定婴幼儿配方乳粉中总蛋白、高分子蛋白和游离氨基酸含量,通过计算求得小分子蛋白肽含量。结果:高分子蛋白检测精密度RSD(n=6)为0.74%;17种氨基酸回收率为91.0%~103.2%,检测结果的相对偏差为0.6%~2.5%;小分子蛋白肽添加回收率为95.2%~98.2%。结论:所建方法精密度和回收率良好,可用于婴幼儿配方乳粉中小分子肽含量的测定。

Objective:Combined with the determination of macromolecular protein,amino acid and total protein,a quantitative analysis method for the content of small molecular peptides in infant formula milk powder was established.Methods:The contents of total protein,polymer protein and free amino acid in infant formula milk powder were determined by Kjeldahl nitrogen determination method,gravimetric method and ion exchange chromatography,and then the contents of small molecular protein peptide were calculated.Results:The precision RSD of the macromolecular protein detection(n=6)was 0.74%;The recovery rates of the 17 kinds of amino acids were 91.0%~103.2%,and the relative deviations of the detection results were 0.6%~2.5%.The recovery rates of small molecular weight peptides were 95.2%~98.2%.Conclusion:The established method has been validated by methodology,with good precision and recovery rate,and can be used for the determination of small molecular peptides in infant formula milk powder.