Identification of characteristic volatiles of Zhenjiang aromatic vinegar using HS-SPME-GC/MS coupled with multivariate analysis

This study employed headspace solid phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC–MS) coupled with multivariate statistical analysis to identify volatile markers in various levels of Zhenjiang Aromatic Vinegar (ZAV). A full range of 40 volatile organic compounds (VOCs) were identified and categorized into acids, alcohols, esters, aldehydes, ketones, heterocyclic compounds and others. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) demonstrated a clear clustering effect among different levels of ZAV, indicating distinct volatile characteristics at the relative content level. Furthermore, using Orthogonal partial least squares discrimination analysis (OPLS-DA), 20 significant volatile organic compounds (VOCs) were identified as markers for distinguishing between the various levels of ZAV. To differentiate among the levels of ZAV, two volatile compounds, acetic acid and n-hexanol, were identified as characteristic volatile compounds using a combination of Venn diagram, analysis of variance (ANOVA) and boxplot analysis. The results showed notable variations in VOCs among ZAV samples of different grades. Acetic acid and n-hexanol can serve as reliable markers for grade distinction, providing valuable technical and theoretical support for the production and quality control of ZAV.