Abstract: One-factor-at-a-time and orthogonal array design methods were used to optimize the major reaction conditions affecting the determination of amino acid content in sterilized milk by ninhydrin colorimetric method. Water-bath heating time influenced significantly determination results so that it required strict control. The optimal determination conditions were 1.2 mL of ninhydrin solution and heating for 30 min in 70 ℃ water-bath. Under these conditions, the amino acid content in sterilized milk was determined to be 1.62 g/100 mL.

Key words: sterilized milk；amino acid；determination conditions

摘要： 考察茚三酮比色法测定灭菌乳中氨基酸条件的主要影响因素。通过单因素及正交试验对其测定条件进行改进。结果表明：水浴时间对测定结果影响显著,要严格控制。茚三酮比色法测定灭菌乳中氨基酸的最佳条件为：水浴时间30min、水浴温度70℃、茚三酮用量1.2mL,在此条件下测得灭菌乳中氨基酸含量为1.62g/100mL。

关键词: 灭菌乳; 氨基酸; 测定条件