Abstract: The composition and content of amino acids in infant formula sold in China were investigated in comparison with human milk at different lactation stages. An amino acid analyzer was used to detect the contents of free and hydrolyzed amino acids in commercial infant formula, and total amino acid content and the proportion of individual amino acids were calculated. The results showed that free amino acids were detected in some of the 12 samples, while hydrolyzed amino acids were detected in all these samples. The average concentration of most amino acids was close to that of human milk at 1 to 60 d of lactation, and higher than that of human milk at 61 to 180 d. The average ratio of essential to total amino acids was 46.43%, which was close to that of human milk. The proportions of methionine and tryptophan to total amino acids were higher than those of human milk, the proportions of arginine and cystine to total amino acids were lower than those of human milk, and the proportion of other amino acids to total amino acids was close to that of human milk. This study reveals the difference in amino acid content between commercial infant formula and human milk.

Key words: infant, milk powder, human milk, amino acid

摘要： 研究我国市售婴儿配方乳粉的氨基酸组成和含量与呈动态变化的母乳成分的差异。采用氨基酸分析仪检测市售婴儿配方乳粉的游离氨基酸和水解氨基酸含量，并计算总氨基酸含量和各单体氨基酸占总氨基酸的比例，同时与系统综述的中国母乳数据进行对比。结果表明：12 份市售婴儿配方乳粉中仅部分乳粉样品检出游离氨基酸，全部乳粉样品均检出水解氨基酸；大部分氨基酸的质量浓度平均值与1～60 d母乳平均值接近，高于61～180 d母乳平均值；必需氨基酸占总氨基酸的质量分数平均值为46.43%，与母乳接近；各单体氨基酸中蛋氨酸和色氨酸占总氨基酸的比例高于母乳，精氨酸和胱氨酸占总氨基酸的比例低于母乳，其他氨基酸占总氨基酸的比例和母乳接近。目前市售婴儿配方乳粉的氨基酸含量与呈动态变化的母乳之间存在差异。

关键词: 婴儿, 乳粉, 母乳, 氨基酸