Widely targeted metabolomics reveals blue-green light-mediated regulation of bioactive compound accumulation in postharvest pepper fruits

Pepper (Capsicum annuum L.) fruits are rich in bioactive compounds essential for nutritional quality. This study evaluated the effects of combined blue-green light on postharvest metabolite accumulation, using dark treatment as a control. After 36 h exposure, widely targeted metabolomics identified 1270 metabolites, with flavonoids, phenolic acids, and lipids being the major classes. KEGG analysis showed significant enrichment in flavonoid biosynthesis, phenylpropanoid biosynthesis, and linoleic acid metabolism under combined light. Compared with the control, combined light significantly markedly increased carotenoids, total flavonoids, and total phenolics by 12.76%, 262.50%, and 99.19%, respectively, and enhanced antioxidant enzyme activities by 24.61%, 31.67%, and 268.16%. Soluble sugar, protein, and vitamin C contents also increased by 68.48%, 31.48%, and 37.77%, respectively. Notably, combined light induced more upregulated differential metabolites than single blue or green light, indicating a synergistic effect. Overall, blue-green light enhances bioactive compound accumulation and antioxidant capacity via coordinated metabolic regulation in pepper fruits.