Dynamic Changes in Physicochemical Properties and Volatile Metabolites during Tomato Peel Residue Vinegar Fermentation

Tomato peel residue is rich in a variety of nutrients and bioactive substances, rendering it a potential high - quality raw material for fruit vinegar fermentation. This study conducted a systematic investigation into the dynamic changes in physicochemical properties and volatile metabolites during the three stages (enzymatic hydrolysis, fermentation, and vinegar production) of tomato peel residue fruit vinegar fermentation. The results indicated that the polyphenol content decreased significantly during the fermentation process, whereas the contents of flavonoids and lycopene remained stable, and the total antioxidant capacity increased significantly. The contents of glutamic acid, succinic acid, and quinic acid in the fruit vinegar were 0.026 ± 0.002 g/L, 1200.94 ± 36.03 mg/L, and 30.46 ± 1.52 mg/L, respectively. Electronic nose and electronic tongue analyses could effectively distinguish samples from different fermentation stages, and the cumulative variance explanation rate exceeded 99%. Among the volatile metabolites, 266 esters, 231 terpenoids, and 154 ketones were identified. Terpenoid biosynthesis, carbon metabolism, and phenylalanine metabolism are the core pathways for flavor formation during the fermentation process. These findings provide a theoretical basis and practical foundation for the comprehensive development and utilization of tomato peel residue. • Tomato peel residue was used in full-substrate liquid fermentation. • Flavoromics analyzed volatile metabolite evolution during fermentation. • Terpene synthesis and phenylalanine metabolism shaped the final flavor. • Metabolite trends clustered into seven distinct groups. • A key aroma compound peaked in both raw tomatoes and final vinegar.