Composite Films of Gelatin/Sodium Alginate Loaded with Benzyl Isothiocyanate and Eugenol Essential Oils: Characterization and Application in the Preservation of Cherries and Beef

In this study, two antimicrobial food packaging films were prepared by using gelatin/sodium alginate (GSA) as the film substrate and introducing benzyl isothiocyanate (BITC) and eugenol (EUG), respectively. The incorporation of BITC and EUG increased the tensile strength of the GSA film by 66.7% and 32.2%, respectively, while reducing the elongation at break by 44.9% and 39.8%, respectively. The water contact angle increased by 50.4% and 14.9%, and the water vapor permeability decreased by 65.4% and 59.2%, respectively, indicating that the addition of BITC and EUG improved the water resistance of the GSA film. In addition, the incorporation of BITC and EUG reduced the light transmittance of the GSA film. Scanning electron microscopy revealed that the surface inhomogeneity of the GSA film improved after the addition of BITC and EUG. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) indicated that BITC and EUG interacted with the GSA matrix and affected the structural and thermal characteristics of the composite films. Application tests on cherries and beef have shown that BITC-GSA and EUG-GSA films delayed quality deterioration during storage. Overall, these films show promising potential as biodegradable active packaging materials for food preservation. These two films were applied to cherries and beef, effectively extending their shelf life and demonstrating the potential of these films as food packaging materials.