Dynamic changes in volatile flavor compounds and capsaicinoids and their interrelationships in eight chili pepper cultivars across three ripening stages

Abstract

This study investigated dynamic changes in volatile organic compounds and capsaicinoids during the maturation of eight chili pepper cultivars and their interrelationships. Gas chromatography–ion mobility spectrometry (GC-IMS) was used to analyze fruits at three ripening stages, resulting in the identification of 57 volatile compounds, mainly esters and alcohols. Relative odor activity value (ROAV) analysis identified butanoic acid ethyl ester and 3-methylbutanal as key aroma-active compounds, whose aroma contributions increased during ripening. Orthogonal partial least squares discriminant analysis (OPLS-DA) effectively differentiated samples by cultivar and maturation stage, and 28 differential compounds were selected on variable importance in projection scores. The total capsaicinoid content ranged from 785.7–2587.6 μg/g at the green stage and reached 462.3–3065.2 μg/g at maturation stage, indicating marked cultivar-specific variation. Capsaicin and dihydrocapsaicin both showed a significant positive correlation with esters, with correlation coefficients of r = 0.518 (p < 0.05) and r = 0.579 (p < 0.01), respectively. These findings suggest a close association between pungency and aroma formation during chili pepper ripening and provide theoretical support for the breeding of high-quality pepper cultivars and scientifically informed harvest strategies.