Dynamic evolution of pungency and aroma profiles in eight pepper cultivars of three Capsicum species at different fruit maturation.

Eight pepper accessions representing three Capsicum species were sampled at the mature green (MG), color turning (TR), and red ripe (RR) stages. High-performance liquid chromatography (HPLC) and Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used separately to quantify capsaicinoid levels and characterize volatile organic compound (VOC) profiles. Combined ANOVA, principal component analysis, HCA and OPLS-DA analyses were performed to dissect the effects of cultivar genotype and fruit maturity on pungency and flavor traits. The results indicated that both genotype and ripening stage significantly modulated pungency and aroma. Genotypically, Capsicum chinense (MGJ) exhibited the highest capsaicinoid accumulation, with content increasing from 55.777 g/kg at the MG stage to 70.5957 g/kg at the RR stage. Capsicum frutescens (LA-111) followed, with capsaicinoid content ranging from 5.603 g/kg at the MG stage to 8.449 g/kg at the RR stage. Capsicum annuum displayed the lowest capsaicinoid content, varying from 0.099 g/kg in line GC-2 at the MG stage to 0.759 g/kg in line LZ-85 at the RR stage. Maturation consistently increased capsaicinoid content across all cultivars (relative increases: 24%-73%) and shifted VOC profiles from green-leafy (hexanal and pyrazines) to sweet/fruity. Results demonstrate that cultivar genotype determines the basal levels of capsaicinoids and key volatile classes, whereas fruit maturity governs their dynamic accumulation and sensory transformation. These findings provide integrated theoretical guidance for pepper breeding, optimal harvest timing, and targeted industrial processing.