Abstract:To investigate the differences in quality characteristics and natural product compositions among the three main cultivated new plum cultivars (Xinmei 1, Xinmei 2, and Xinmei 3) in Jiashi County, Xinjiang, this study employed ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS)-based untargeted metabolomics to analyze 11 fruit samples at the mature stage. A total of 281 natural products were identified, belonging to 17 classes, among which flavonoids (63, 22.42%), terpenoids (54, 19.22%), and phenolic acids (30, 10.68%) were the three major categories. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) revealed that a total of 147 differential metabolites were screened among varieties, with flavonoids accounting for the highest proportion (32.6%), indicating they are the core chemical markers for variety discrimination. The flavor and functional characteristics of the different cultivars are distinctly differentiated: Xinmei 1 exhibits a coordinated and rich profile of terpenoids, phenolic acids, and amino acid derivatives, with a pronounced sweet aroma, and possesses the best overall antioxidant quality; Xinmei 2 contained an exceptionally high relative content of organic acids (62.13%), with pronounced acidity, making it suitable as a natural acidulant raw material; Xinmei 3 features prominent proportions of flavonoids (19.93%) and nucleosides (47.92%), making it suitable for developing high antioxidant functional foods. This study provides a theoretical foundation for variety identification and selection of raw materials for high-value-added products of Jiashi Xinmei.