Novel chitosan/zein bilayer films incorporating grape seed extract and nisin: Preparation, characterization and application in pork shelf-life extension

Fresh pork is highly perishable and prone to oxidative degradation and microbial contamination. This study was designed to fabricate an active chitosan/zein bilayer film incorporating grape seed extract (GSE) and nisin, and to assess its efficacy in preserving the quality of fresh pork during refrigerated storage. Results revealed that the inclusion of active agents significantly improved the film's barrier properties, with the CNG film (containing both GSE and nisin) exhibiting the lowest water vapor permeability and oxygen permeability. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis confirmed excellent compatibility and strong intermolecular interactions between the active agents and the film matrix, with the CNG film showing enhanced interfacial penetration between layers. The CNG film also demonstrated superior water sensitivity modulation, along with the strongest UV-blocking capacity and sustained release behavior in food simulants. During pork packaging trials, the CNG film effectively retarded quality deterioration, as evidenced by the highest shear force retention, minimal color change, and lowest cooking loss . Furthermore, the CNG film significantly inhibited lipid oxidation, protein oxidation and microbial growth. Therefore, this bilayer active film demonstrates high potential as a viable edible packaging material for fresh meat preservation.