目的 分析低温酸奶储存过程中必需氨基酸和非必需氨基酸含量的变化.方法 使用氨基酸分析仪对样品中氨基酸的组成及含量进行分析.结果 搅拌型酸奶中必需氨基酸含量显著高于凝固型酸奶(P<0.05),其中搅拌型酸奶-Ⅱ的必需氨基酸含量最高, 达到40.93 g/100 g蛋白.5种低温酸奶中谷氨酸含量最高, 显著高于其他氨基酸(P<0.05), 其最高值为(22.16±0.04) g/100 g蛋白.半胱氨酸含量显著低于其他氨基酸(P<0.05),其最低值为(0.15±0.00) g/100 g蛋白.必需氨基酸中缬氨酸和异亮氨酸含量在储存6 d时达到最大值, 亮氨酸和赖氨酸含量在储存3 d时达到最大值.非必需氨基酸中丝氨酸、脯氨酸和半胱氨酸在储存6 d时含量降到最低.结论 储存过程中乳酸菌发酵对必需氨基酸和非必需氨基酸的代谢产生影响, 缬氨酸、赖氨酸、异亮氨酸、亮氨酸、脯氨酸、半胱氨酸和丝氨酸含量都发生显著变化.%Objective To investigate the changes of concentrations of essential amino acids and non-essential amino acids in cool yoghurt during storage. Methods Amino acid analyzer was used for the determination of compositions and concentrations of amino acids. Results The concentration of essential amino acids in stirred yogurt was significantly higher than that in set yogurt (P<0.05). The concentration of essential amino acids in stirred yogurt- was Ⅱ the highest, and the value was 40.93 g/100 g. The concentration of glutamic acid was significantly higher than the others in the 5 kinds of yogurt (P<0.05), and the highest value was (22.16±0.04) g/100 g. The concentration of cysteine was significantly lower than the others in the 5 kinds of yogurt (P<0.05), and the lowest value was (0.15±0.00) g/100 g. The concentrations of valine and isoleucine of essential amino acids reached the maximum at 6 d during storage, the content of leucine and lysine reached the maximum at 3 d during storage, and the content of serine, proline and cysteine of non-essential amino acids reached the minimum at 6 d during storage. Conclusion The metabolism of essential amino acids and non-essential amino acids is affected by the fermentation of lactic acid bacteria. The concentrations of valine, lysine, isoleucine, leucine, praline, cysterine and serine are significantly changed.
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