Ripening-Associated Changes in Physicochemical Properties and Metabolomic Profiles of Processing Tomato

Understanding ripening-associated physicochemical and metabolic changes is essential for evaluating quality development and optimizing harvest maturity in processing tomatoes. In this study, the processing tomato cultivar "Zhongshu 5810" (Solanum lycopersicum L.) was investigated across six consecutive ripening stages using physicochemical analysis, LC-MS-MS, and HS-SPME-GC-MS-based metabolomics. During ripening, total soluble solids significantly increased, whereas γ-aminobutyric acid and total phenolic content significantly decreased (p < 0.05). GC-MS identified 77 volatile compounds, and the 20 volatile compounds with the highest VIP scores were selected as candidate markers of ripening-related aroma variation, revealing stage-dependent remodeling of volatile metabolism. LC-MS detected 4157 non-volatile features and revealed pronounced stage-dependent remodeling of the non-volatile metabolome, with distinct accumulation patterns among diverse chemical classes. Multivariate analysis and pathway enrichment analysis indicated that amino acid, nucleotide, cofactor, and lipid-related metabolism contributed substantially to ripening-associated metabolic variation. These findings provide a comprehensive characterization of quality-related metabolomic changes during processing tomato ripening and identify potential maturity-associated indicators for harvest optimization and quality management.