Spatiotemporal dynamics of sugars, acids, phenolics, and flavor in the peel and pulp of five plum cultivars

Plum is highly valued for its distinctive flavor and health benefits. This study comprehensively evaluated the dynamic changes in fruit quality of five Chinese plum cultivars (‘Kuli’, ‘Qiangcui’, ‘Yinhong’, ‘Naili’, and ‘Cuihong’) across five developmental stages, integrating phenotypic traits, primary metabolites, bioactive substances, and electronic tongue-based sensory evaluation. Fruit growth followed a typical double-sigmoid pattern, with ‘Naili’ showing the largest fruit (70.5 g). Soluble sugars increased gradually, while organic acids and most bioactive substances declined during development. Sucrose accumulated rapidly at late stages, while glucose and fructose remained the major sugars. ‘Qiangcui’ pulp exhibited the highest sugar-acid ratio at maturity (13.7). Peel consistently contained higher phenolic levels than pulp. ‘Cuihong’ peel had the highest total phenolic content (4.8 mg·g -1 ) at maturity. Procyanidins B1/B2 constituted the major fraction of the phenolics in most cultivars. Electronic tongue analysis revealed distinct cultivar- and tissue-specific taste profiles. ‘Kuli’ displayed the highest sourness and astringency, while the pulp of ‘Cuihong’ and ‘Naili’ showed superior richness and umami. These findings demonstrate substantial diversity in flavor and functional quality among plum cultivars and tissues, providing useful information for consumers seeking preferred taste, improved eating quality, and greater health-promoting value.