Flavor-guided superior variety selection for round bell Paojiao: An integrated GC-MS metabolomics and chemometrics...

To screen fresh round bell-pepper varieties suitable for processing high-quality paojiao and to elucidate the mechanisms underlying quality formation, thereby providing a theoretical basis for the breeding of paojiao-specific varieties, this study systematically evaluated five self-bred round bell-pepper cultivars (P1-P5) in terms of their raw material characteristics, as well as the physicochemical properties, texture, color, volatile flavor profiles, and sensory quality of the resulting paojiao. Results indicated that variety significantly influenced the final quality. P5 received the highest overall sensory score. Odor activity values (OAVs) revealed 11 key odorants (e.g., guaiacol, (±)-trans-nerolidol and so on) contributing to the typical aroma. P5 exhibited significantly higher unique volatile content (16.23%), correlating with its distinct flavor profile and superior sensory acceptance. Orthogonal partial least squares-discriminant analysis (OPLS-DA, R²X = 0.972, R²Y = 0.993) identified 19 key markers (VIP > 1), with R-fruit width (VIP = 2.56), R-b* (VIP = 1.75), and R-pectin (VIP = 1.73) being the most significant. Correlation analysis further demonstrated that sensory scores (morphology, color, texture) were positively correlated with protopectin and total acid contents, but negatively with reducing sugars. Raw material texture (hardness, chewiness) also significantly influenced the final color. The self-bred cultivar P5 was identified as the optimal variety for producing high-quality paojiao, with fruit size, texture, and pectin content serving as the key determinants of the sensory quality of the paojiao. This study provides an important basis for the breeding of paojiao-specific varieties and the quality control of raw materials.