Preparation and characterization of Pleurotus eryngii polysaccharides/hyperbranched poly-L-lysine composite film and its application in cherry preservation

In this study, Pleurotus eryngii polysaccharides (PEP)-hyperbranched poly-L-lysine (HBPL) composite film was prepared, and its physicochemical and functional properties were characterized. Subsequently, cherries were selected as the model system to evaluate the preservation efficacy of the composite film. By monitoring changes in key physical and chemical parameters as well as enzymatic activities during storage, the postharvest preservation effects of the PEP-HBPL film on fruits were assessed. The results indicated that the PEP-HBPL composite film exhibited excellent mechanical strength, flexibility, favorable surface morphology, antibacterial activity, and significant antioxidant activity. Application of the PEP-HBPL film effectively mitigated weight loss and fruit softening, reduced the degradation of titratable acidity, ascorbic acid, and total phenols, and suppressed the accumulation of total soluble solids and malondialdehyde in cherries. Furthermore, the composite film enhanced the activities of superoxide dismutase, catalase, and peroxidase, while simultaneously inhibiting the rise in polyphenol oxidase activity. In conclusion, these findings demonstrated that the PEP-HBPL composite film could effectively extend the postharvest shelf life of cherries, underscoring its promising potential as an active fruit packaging material. • A new film was developed using Pleurotus eryngii polysaccharides and hyperbranched poly-L-lysine. • The film had high mechanical strength, flexibility, and antioxidant activity. • The film maintained cherry quality by reducing weight loss, softening, and nutrient decay. • The film extended shelf-life by enhanced the antioxidant enzyme system.