“Nuomici” Litchi Pericarp Waste Transformed Into Activated Film for Food Packaging

The antioxidant composite film was prepared by blending the pericarp extract of the Chinese litchi variety “Nuomici” (NLPE) with chitosan (CS). The study examined the impact of various NLPE concentrations (0%, 2%, 5%, 10%, and 15% [w/v]) on the mechanical properties, water vapor barrier, UV–visible light barrier, and antioxidant properties of the CS film. The results indicated that the composite films displayed superior antioxidant and UV-barrier properties, accompanied by lower water vapor permeability coefficients, water content, elongation at break, and tensile strength, compared to the pure CS film. Fourier-transform infrared (FTIR) spectroscopy, SEM, and x-ray diffraction were employed to analyze the hydrogen bonding between CS and NLPE, revealing their excellent compatibility. Furthermore, fruit preservation studies demonstrated that CS composite film containing 5% (w/v) NLPE retarded weight loss and shrinkage of green grapes more effectively than both the pure CS film and the control group without film packaging. Therefore, CS/NLPE film holds significant potential and value for practical applications in food packaging, while also offering a novel approach for the reuse of waste resources and sustainable packaging.