山西老陈醋晒制前后挥发性风味物质变化

采用顶空-固相微萃取结合气相色谱-质谱联用、气相色谱-嗅闻对晒制前后山西老陈醋挥发性风味物质进行分析,基于保留指数、质谱、标准品,气-质联机共鉴定出84种挥发性风味物质,气相色谱-嗅闻鉴定出42种香气活性化合物,包括含硫化合物、含氮杂环、含氧杂环、醛类、酮类、醇类、酸类、酯类、酚类、其他类。其中2种醋中含量较高的为乙酸、四甲基吡嗪、糠醛、糠醇、2,3-丁二酮等20种化合物,检测频率较高的为3-甲硫基丙醛、2-乙基-3,5-二甲基吡嗪、2-呋喃丙烯醛、香兰素、乙酸、3-甲基丁酸等16种化合物。从化合物种类看,晒后新出现了3-甲硫基丙醇、2-乙酰基呋喃、苯甲醇、丙酸等14种化合物,但有二甲基二硫醚、苯丙酮、丁酸、3-甲基戊酸、丁酸乙酯、2-乙酰基吡咯、5-羟甲基糠醛等19种化合物消失。从化合物含量变化看,晒后四甲基吡嗪、糠醇、苯乙醇、丙酸、乙酸苯乙酯等11种香气活性化合物含量升高,而乙酸、糠醛、己酸、二苯甲酮等29种香气活性化合物的含量降低。总体上,晒制后有杂味的化合物种类及含量降低,而具有良好香气特性的化合物种类或含量增加。研究结果可为山西老陈醋生产工艺的升级改造提供参考。

Changes of Volatile Flavor Compounds in Shanxi Aged Vinegar Before and After Aging

The samples of Shanxi aged vinegar before and after aging were analyzed by headspace solid-phase microextraction combined with gas chromatography-mass spectra and gas chromatography-olfactometry. Based on retention indices, mass spectra, and injection of authentic standards, a total of 84 volatile compounds were identified by GC-MS and 42 odor-active compounds were identified by GC-O, including sulfur-containing compounds, nitrogen-containing heterocycles, oxygen-containing heterocycles, aldehydes, ketones, alcohols, acids, esters, phenols and others. For both the vinegars before and after aging, 20 compounds were found in a major amount, such as acetic acid, tetramethyl pyrazine, furfural, furfuryl alcohol, 2,3-butanedione, and so on. Meanwhile 16 compounds were found with high detection frequencies, such as 3-methylthio propanal, 2-ethyl-3,5-dimethyl pyrazine, 2-furanacrolein, vanillin, acetic acid, 3-methyl butanoic acid, and so on. However, according to the total number of compounds, after aging, 14 compounds were newly detected, e.g. 3-methylthio-1-propanol, 2-acetylfurane, benzyl alcohol, and propanoic acid, whereas 19 compounds were disappeared, e.g. dimethyl disulfide, benzyl acetone, butanoic acid, 3-methylpentanoic acid, ethyl butyrate, 2-acetyl pyridine, and 5-hydroxymethyl furfural. According to amounts of the compounds, those of the 11 odoractive compounds (e.g. tetramethyl pyrazine, furfuryl alcohol, phenylethyl alcohol, propanoic acid, and phenethyl acetate) were markedly increased; whereas those of the 29 odor-active compounds (e.g. acetic acid, furfural, hexanoic acid, and benzophenone) were decreased. Overall, the aging processing resulted in decrease of compounds with off-flavors and simultaneously increase of compounds with pleasant flavors. The research results were expected to provide guidance for improving or up-grading the production technology of Shanxi aged vinegar.