Characterization of volatile compounds in three commercial Chinese vinegars by SPME-GC-MS and GC-O

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were carried out to qualitatively and quantitatively characterize the volatiles and aroma-active compounds in three commercial Chinese vinegars, including Zhengrong Rice Vinegar (ZRV), Zhenjiang Aromatic Vinegar (ZAV), and Longmen Smoked Vinegar (ISV). With the aid of DVB/CAR/PDMS fiber, a total of 75 volatile compounds were identified. Among them, 42 aromas were confirmed by their corresponding authentic chemicals. After comparison of the identified volatiles between the three vinegars, the ZAV sample was found to contain more alcohols and acids, the ZRV sample had more esters and phenols, while the LSV sample was shown to have more identified compounds in the ketones, aldehydes, and pyrazines. In regard to the quantitation, the volatiles that were found in high concentrations included acetic acid (at 14.64, 31.95 and 194 mg/L), furfural (at 5.49, 43.81 and 33.01 mg/L) and tetramethyl pyrazine (at 10.39, 13.51 and 19.41 mg/L) in ZRV, ZAV and ISV, respectively. Moreover, thirty volatiles were identified by GC-O as aroma-active compounds that made contributions to the respective flavor profiles of the commercial Chinese vinegar. Eighteen of them were recognized as contributors for all the three commercial Chinese vinegars under this study.