Xu Hao, Qiu Shuyi, Dai Yifeng, Wu Yuangen, Zeng Xiangyong
Guizhou Province Key Laboratory of Fermentation Engineering and Biopharmacy, School of Liquor and Food Engineering, Guizhou University, Guiyang 550025, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China.
Foods. 2022 Aug 27;11(17):2607. doi: 10.3390/foods11172607.
Enantiomers of lactic acid were investigated in Baijiu, including soy sauce aroma-type Baijiu (SSB), strong aroma-type Baijiu (STB), and light aroma-type Baijiu (LTB), via high-performance liquid chromatography with a chiral separation column. The natural concentration and enantiomeric distribution of lactic acid were studied, and their contribution to the flavor of Chinese Baijiu was evaluated based on recognition threshold. The results showed that there were significant differences in the content of lactic acid and the ratio of enantiomeric isomers among different aroma types and storage year. In SSB, the concentrations of D-lactic acid and L-lactic acid were higher, with the highest concentrations of 1985.58 ± 11.34 mg/L and 975.31 ± 14.03 mg/L, respectively. In STB, the highest concentrations of D-lactic acid and L-lactic acid were 1048.00 ± 11.46 mg/L and 939.83 ± 0.23 mg/L, respectively. In LTB, the highest concentrations of D-lactic acid and L-lactic acid were 760.90 ± 9.45 mg/L and 558.33 ± 3.06 mg/L, respectively. The average D/L enantiomeric ratios were 78:22 ± 16.16 and 80:20 ± 9.72 in the Commercial Baijiu products of SSB and STB, respectively. The average D/L enantiomeric ratio in LTB was 90:10 ± 6.08. D-lactic acid in JSHS vintage Baijiu showed a wave variation with aging, while L-lactic acid gradually increased during aging, and the average D/L enantiomeric ratio was 76:24 ± 4.26. The concentration of D-lactic acid in XJCT vintage Baijiu also showed a wave variation with aging, and the concentration of L-lactic acid tended to be stable during aging, with an average D/L enantiomeric ratio of 88:12 ± 2.80. The content of the two configurations of lactic acid in the LZLJ vintage Baijiu showed a decreasing trend during aging, with an average D/L enantiomeric ratio of 60:40 ± 11.99. The recognition threshold of D-lactic acid in 46% ethanol solution was 194.18 mg/L with sour taste; while the L-lactic acid was 98.19 mg/L with sour taste. The recognition threshold of L-lactic acid was about half that of D-lactic acid, indicating that L-lactic acid has a stronger sour taste. The taste activity values (TAVs) of D-lactic acid and L-lactic acid were greater than 1 in most of the Baijiu samples, and the TAV of D-lactic acid was greater than that of L-lactic acid. The study showed that the lactic acid enantiomers contributed to the taste perception of Baijiu in most of the samples, and D-lactic acid contributed more to the Baijiu taste than L-lactic acid.
通过使用手性分离柱的高效液相色谱法，对白酒中的乳酸对映体进行了研究，这些白酒包括酱香型白酒（SSB）、浓香型白酒（STB）和清香型白酒（LTB）。研究了乳酸的自然浓度和对映体分布，并基于识别阈值评估了它们对中国白酒风味的贡献。结果表明，不同香型和储存年份的白酒中，乳酸含量和对映体异构体比例存在显著差异。在酱香型白酒中，D-乳酸和L-乳酸的浓度较高，最高浓度分别为1985.58±11.34mg/L和975.31±14.03mg/L。在浓香型白酒中，D-乳酸和L-乳酸的最高浓度分别为1048.00±11.46mg/L和939.83±0.23mg/L。在清香型白酒中，D-乳酸和L-乳酸的最高浓度分别为760.90±9.45mg/L和558.33±3.06mg/L。酱香型白酒和浓香型白酒商品酒的平均D/L对映体比例分别为78:22±16.16和80:20±9.72。清香型白酒的平均D/L对映体比例为90:10±6.08。酱香型白酒中D-乳酸含量随陈酿呈波动变化，而L-乳酸在陈酿过程中逐渐增加，平均D/L对映体比例为76:24±4.26。浓香型白酒中D-乳酸含量也随陈酿呈波动变化，L-乳酸含量在陈酿过程中趋于稳定，平均D/L对映体比例为88:12±2.80。清香型白酒中两种构型乳酸的含量在陈酿过程中呈下降趋势，平均D/L对映体比例为60:40±11.99。46%乙醇溶液中D-乳酸的识别阈值为194.18mg/L，有酸味；L-乳酸的识别阈值为98.19mg/L，有酸味。L-乳酸的识别阈值约为D-乳酸的一半，表明L-乳酸酸味更强。在大多数白酒样品中，D-乳酸和L-乳酸的味觉活性值（TAVs）均大于1，且D-乳酸的TAV大于L-乳酸。研究表明，在大多数样品中，乳酸对映体对白酒的味觉感知有贡献，且D-乳酸对白酒味道的贡献大于L-乳酸。
