Chitosan/collagen films loaded with Pleurotus ostreatus polysaccharide-epigallocatechin gallate conjugates with excellent antioxidant and antibacterial activities for pork preservation

Abstract

The purpose of this study was to develop a multifunctional active food packaging composite films to solve the environmental and health problems of traditional petroleum-based plastic packaging and for food preservation. The chitosan (CS) based-functional films were prepared by blending collagen (Clg), Pleurotus ostreatus polysaccharide-Epigallocatechin gallate conjugates (POP-EGCG) and ε-Polylysine (ε-PL, PL). The mechanical, physical and chemical properties, antioxidant, antibacterial activity and application in pork preservation were studied. The results showed strong intermolecular hydrogen bond interactions among Clg, POP-EGCG, and ε-PL led to denser, more uniform film surfaces and cross-sections, which significantly enhanced the thermal stability, crystallinity, tensile strength (221.73 %), and elongation at break (21.33 %) of the CS/Clg/POP-EGCG/PL film (P < 0.05). The CS/Clg/POP-EGCG/PL films exhibited excellent water resistance, oxygen barrier properties, UV blocking, slow-release capability, and biosafety. They also demonstrated strong antioxidant (DPPH: 93.10 ± 0.51 %; ABTS: 94.13 ± 0.57 %) and antibacterial effects, thus effectively delaying pork lipid oxidation and microbial growth during refrigeration and extending shelf life by 5 days. This study offers a novel active packaging strategy to extend fresh pork shelf life, facilitating practical applications of CS/CO/POP-EGCG/PL films in food packaging.