Starch/carboxymethyl cellulose-based photodynamic packaging material delays the quality deterioration of snap beans via ROS metabolism regulation

Snap beans (Phaseolus vulgaris L.) are prone to rapid senescence and quality deterioration during postharvest storage. In this study, the effect of a novel carbon dot/g-C3N4-mediated starch/carboxymethyl cellulose-based photodynamic film (CCPF) on the postharvest quality deterioration and reactive oxygen species (ROS) metabolism of snap bean pods was investigated. CCPF packaging influenced gas composition regulation, ethylene degradation and microbial infection, which resulted in snap bean pods with lower respiratory metabolism and less quality loss. In addition, the snap bean pods in the CCPF group maintained the content of nonenzymatic antioxidants, low activities of pro-oxidative enzymes and high activities of antioxidant enzymes compared to other groups, thus decreasing electrolyte leakage, malondialdehyde accumulation, H2O2 accumulation and the O2·- generation rate. Overall, CCPF packaging effectively delayed postharvest senescence and extended the shelf life of snap beans by reducing respiration and regulating ROS metabolism. Pearson’s correlation analysis confirmed that postharvest senescence correlated with ROS metabolism in snap bean pods. This study offers theoretical evidence for a method to preserve snap bean pods and can be used as a valuable reference for the practical application of novel CCPF packaging. •A novel photodynamic nanocomposite film was developed for snap bean preservation.•The snap beans packaged with photodynamic film maintained better commercial quality.•Photodynamic film packaging delayed the postharvest senescence of snap bean pods.•Photodynamic film packaging regulated the ROS metabolism of snap bean pods.