Improving properties of Litsea cubeba oil Pickering emulsion-loaded gelatin-based bio-nanocomposite film via optimizing blending ratio: Application for mango preservation

To improve the biological and water-barrier properties of gelatin film, we incorporated the red roselle extract (RRE), ZnO nanoparticles (ZnO), and Litsea cubeba oil Pickering emulsion (LCON) into the GE film. The effect of RRE, ZnO, and LOCN on the properties of GE film was assessed using Box–Behnken response surface design (BBD). The BBD results revealed that these compounds greatly affect the properties of the film, especially the contribution of ZnO/LCON on the mechanical and water barrier properties of the film. The optimal antifungal (80.15%), antibacterial (31.24 mm), antioxidant (73.00%), tensile strength (42.03 MPa), elongation at break (25.50%), water vapor permeability (18.01 g mm·m−2·Kpa−1·h−1), and water contact angle (110.2°) of the film were obtained at 1.10% RRE, 1.51% ZnO and 2.38% LCON. The X-ray diffraction pattern and FTIR spectra results indicated the change of molecular interactions and semi-crystalline structure in the film. The scanning electron microscopy, fluorescence image, and energy dispersive X-ray results revealed that the excellent dispersion of RRE, ZnO, and LCON in the GE matrix led to an even and smooth structure in the film. This structure offers a positive effect on improving the mechanical and barrier properties of the film. The colorful patterns were successfully printed on the film to provide essential product information. Due to its excellent biological, mechanical, and barrier properties, the optimized film was applied for mango preservation. The optimized GE/RRE/ZnO/LCON film significantly controlled the postharvest quality and anthracnose in mango. Thus, the GE/RRE/ZnO/LCON film has great potential for mango preservation in active packaging applications.