Abstract:The samples of Shanxi aged vinegar before and after aging were treated by simultaneous distillation and solvent extraction (SDE). The extracts from the two vinegars were analyzed by gas chromatography-mass spectra (GC-MS) and gas chromatography-olfactometry(GC-O). Based on retention indices, mass spectra, and injection of authentic standards, a total of 184 volatile compounds were identified, including sulfur-containing compounds, nitrogen-containing heterocycles, oxygen-containing heterocycles, aldehydes, ketones, alcohols, acids, esters, phenols, ethers, and others. The major volatile compounds found in both the vinegars before and after aging included acetic acid, acetoin, furfural, 2,3-butanedione, etc. However, compared to the vinegar before aging, the amounts of pyrazine compounds, especially tetramethylpyrazine, were markedly increased in the aged vinegar. By GC-O analysis, according to retention indices, sniffed odor characteristics, identifications in the GC-MS, and comparison of the analytical parameters with those of the authentic standards, a total of 23 odor-active compounds were identified, where 10 compounds were found with high FD values in the vinegar before aging, including acetic acid, acetoin, 2,3-butanedione, ethyl lactate, guaiacol, etc; and 20 compounds were found with high FD values in the vinegar after aging, including 3-methyl propyl alcohol, furfural, phenylacetyldehyde, guaiacol, etc. Comparatively, after aging mainly the odorants of esters were decreased while those of the nitrogen-containing heterocyclic compounds (especially the pyrazine compounds) and the sulfur-containing compounds were increased in the vinegars. The research results are expected to provide guidance for upgrading production technology of the Shanxi aged vinegar.