Flavoromics-Based Characterization of Regional Flavor Profiles and Key Markers in Chinese Glutinous Rice Vinegar

A multi-platform flavoromics approach-comprising headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), high performance liquid chromatography (HPLC), an electronic nose, and an electronic tongue-was used to characterize volatile compounds and representative non-volatile components (organic acids) in glutinous rice vinegar from seven different regions of China. Multivariate statistical analysis was then applied to identify key flavor markers and regional classification features, thereby elucidating the regional flavor patterns of Chinese glutinous rice vinegar. The electronic nose and electronic tongue effectively discriminated among the vinegar samples. In total, 87 volatile compounds were identified, and 17 differential key volatiles were selected based on variable importance in projection (VIP > 1). Acetic acid and lactic acid were the predominant organic acids in the samples. The fused multi-platform orthogonal partial least squares-discriminant analysis (OPLS-DA) model showed the strongest classification performance (R²_X = 0.997, R²_Y = 0.983, Q² = 0.964). Mechanistically, glutinous rice vinegar flavor is shaped by the interplay of fermentation substrates, microbial communities, and processing environments; the decarboxylation of phenolic acids generates phenols and aldehydes/ketones, contributing to aroma complexity, which is consistent with the marker patterns jointly revealed by GC-MS, GC-IMS, and e-nose/e-tongue data and supports geographical origin classification. Overall, this work enhances the understanding of the regional drivers of glutinous rice vinegar flavor and provides a scientific basis for the targeted flavor regulation of traditional vinegar.