Physiological and Molecular Mechanisms Underlying Postharvest Preservation of Peppers

Peppers (Capsicum annuum L.), including pungent chili types and non-pungent sweet and bell types, are a widely cultivated economic crop with high nutritional and commercial importance. Their postharvest behavior varies considerably with species, cultivar, maturity stage, and ripening physiology. In particular, most sweet and bell pepper cultivars are generally considered non-climacteric, whereas some hot pepper genotypes exhibit climacteric-like or intermediate ripening characteristics. Postharvest quality deterioration caused by vigorous respiration, water transpiration, microbial infection and chilling injury severely restricts the sustainable progression of the pepper industry. This article comprehensively reviews the key factors affecting the postharvest quality retention of peppers, including postharvest physiological changes, storage temperature, and packaging methods. Herein, recent advances in chemical, physical, and non-invasive preservation technologies are systematically summarized, and the underlying mechanisms involving sugar and energy metabolism, ethylene-related signaling, antioxidant systems, defense responses, cell wall metabolism, membrane stability and epigenetic regulation are elaborated. Finally, current application constraints and future research perspectives are thoroughly discussed. The review aims to provide a theoretical foundation for developing green, efficient, and sustainable postharvest preservation strategies for peppers.