为了解不同香型白酒中乳酸和乳酸乙酯异构体含量差异，建立了直接测定白酒中乳酸和乳酸乙酯异构体的分离方法，并分析其含量规律。结果表明，乳酸对映体在0.02~0.6 g/L范围内呈线性关系；乳酸乙酯对映体在0.01~2.5 g/L范围内呈线性关系。不同香型白酒乳酸和乳酸乙酯旋光性含量存在显著差异。在酱香型白酒中，D乳酸和L乳酸含量较高，平均质量浓度分别为1.348 g/L和0.440 g/L，浓香型白酒的平均质量浓度为0.402 g/L和0.244 g/L，清香型白酒平均质量浓度为0.161 g/L和0.042 g/L。在酱香型白酒中，D乳酸乙酯和L乳酸乙酯含量较高，平均质量浓度分别为1.280 g/L和0.283 g/L，浓香型白酒平均质量浓度为0.592 g/L和0.352 g/L，清香型白酒的平均质量浓度为0.211 g/L和0.038 g/L。综上所述，该方法操作简便，精密度和准确度高，适用于白酒中乳酸和乳酸乙酯旋光性的测定，明确不同香型白酒在乳酸和乳酸乙酯旋光性含量上的差异，为进一步探究白酒风味形成机制提供数据支撑。

In order to understand the differences in the contents of lactic acid and ethyl lactate isomers in baijiu (Chinese liquor) of different flavor types, a separation method for directly determining the lactic acid and ethyl lactate isomers in baijiu was established, and the content rules were analyzed. It was shown by the results that the enantiomers of lactic acid had a linear relationship within the range of 0.02 - 0.6 g/L; the enantiomers of ethyl lactate had a linear relationship within the range of 0.01 - 2.5 g/L. Significant differences existed in the optical rotation contents of lactic acid and ethyl lactate in baijiu of different flavor types. In Maotai-flavor baijiu, the contents of D-lactic acid and L-lactic acid were relatively high, with the average mass concentrations being 1.348 g/L and 0.440 g/L respectively. The average mass concentrations in Luzhou-flavor baijiu were 0.402 g/L and 0.244 g/L respectively, and those in Fen-flavor baijiu were 0.161 g/L and 0.042 g/L respectively. In Maotai-flavor baijiu, the contents of D-ethyl lactate and L-ethyl lactate were relatively high, with the average mass concentrations being 1.280 g/L and 0.283 g/L respectively. The average mass concentrations in Luzhou-flavor baijiu were 0.592 g/L and 0.352 g/L respectively, and those in Fen-flavor baijiu were 0.211 g/L and 0.038 g/L respectively. All in all, the method was simple to operate, with high precision and accuracy, and was applicable to the determination of the optical rotation of lactic acid and ethyl lactate in baijiu. The differences in the optical rotation contents of lactic acid and ethyl lactate in baijiu of different flavor types were clarified, providing data support for further exploring the flavor formation mechanism of baijiu.

酿酒生物技术及应用四川省重点实验室开放课题（NJ2022-07）；四川轻化工大学研究生创新基金项目（Y2023236）