Gelatin/agar-based multifunctional film integrated with copper-doped zinc oxide nanoparticles and clove essential oil Pickering emulsion for enhancing the shelf life of pork meat

This work reports the fabrication of copper-modified zinc oxide nanoparticles (ZnO@Cu) added gelatin/agar-based multifunctional films loaded with clove essential oil Pickering emulsion (PEC). The ZnO@Cu particles were prepared using a simple precipitation method, and their successful synthesis was verified by X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM) analysis. The clove oil Pickering emulsion was developed using nanocellulose as a solid base. The addition of nanofillers (ZnO@Cu and PEC) improved the films' physical performance. The films' UV-shielding property was similar to 99% enhanced without a significant decrease in their transparency, and the incorporation of fillers also enhanced their mechanical properties. The gelatin/agar films also showed strong antimicrobial activity on ZnO@Cu and PEC addition, where a 100% eradication of L. monocytogenes and similar to 50% decrease in the E. coli population was detected. Further, the antioxidant activity of the functional films was twice the original value obtained for neat films due to the presence of PEC. The developed multifunctional film was applied to wrap the pork belly meat before vacuum packaging, which helped significantly reduce its total aerobic bacterial count and lipid oxidation. The multifunctional film could successfully improve the shelf life of wrapped meat.

Automated summary

This work describes the fabrication of multifunctional films loaded with clove essential oil Pickering emulsion using copper-modified zinc oxide nanoparticles and nanocellulose. The films exhibit excellent physical properties and antimicrobial activity, while also improving UV-shielding and antioxidant activity. When applied in vacuum packaging, these films significantly extend the shelf life of wrapped food.