The dissection of tomato flavor and key nutrients: Chemical composition, biological function and molecular regulation

The decline in flavor and nutritional quality of tomato during domestication and breeding has become a longstanding scientific concern. For example, high-yield breeding has led to a downward trend in the levels of ascorbic acid, glutathione and various key volatile flavor compounds in tomatoes. Current research on tomato flavor and nutritional compounds remains relatively limited, providing insufficient guidance for breeding programs. Consequently, elucidating the biochemical basis and genetic mechanisms underlying tomato flavor and nutrients to provide essential breeding components for high-quality cultivars is an urgent priority for the tomato industry. As a globally significant economic crop, the flavor profile and nutritional functionality of tomatoes directly influence consumer preference and health value. However, the coordinated regulation of flavor and nutrition remains challenging. This review systematically summarizes recent advances in research on tomato volatile and non-volatile flavor compounds and key nutrients, encompassing their chemical properties, compositional functions and molecular regulatory mechanisms. In particular, it clarifies the regulatory roles of key enzyme genes in metabolic pathways and specific transcription factors involved in flavor formation, and elucidates the biological functions and molecular regulatory mechanisms of carotenoids, ascorbic acid and flavonoids. This review further analyzes current technical bottlenecks, such as balancing flavor-nutrition-yield trade-offs and the inherent complexity of metabolic regulation. It proposes future research directions that integrate multi-omics technologies, gene editing and smart sensing technologies. This work provides a scientific theoretical foundation for enhancing tomato quality, developing functional foods, and advancing precision nutrition strategies.