Metabolic alterations associated with chilling injury development in red pepper (Capsicum annuum L.) during low-temperature storage.

Red pepper (Capsicum annuum L.) is stored at low temperatures to maintain freshness; however, prolonged storage can induce chilling stress and quality deterioration. This study investigated metabolic alterations associated with chilling stress during cold storage. Chilling injury (CI) symptoms progressively intensified, became evident after 2 weeks, and were accompanied by pronounced metabolic shifts. Complementary proton nuclear magnetic resonance spectroscopy and gas chromatography-tandem mass spectrometry (GC-MS/MS) analyses revealed metabolite-specific alterations in carbohydrates, amino acids, and organic acids. Multivariate analysis clearly distinguished early (0-2 weeks) and late (4-6 weeks) storage stages, whereas GC-MS/MS profiling showed a marked increase in sucrose (log₂FC = 1.67). Changes in amino acids and tricarboxylic acid cycle-related metabolites were associated with coordinated alterations in central carbon and nitrogen metabolism. These findings provide novel insights into metabolic responses to chilling stress and a metabolic framework for future studies on postharvest management of chilling-sensitive horticultural crops.