Active Eco-friendly Mucilage-Based Films Reinforced with Graphitic Carbon Nitride (g‑C₃N₄) for Sustainable Food...

The increasing global reliance on plastic poses serious environmental and health risks, highlighting the need for biodegradable packaging alternatives. Opuntia ficus-indica mucilage (OFIM) is a promising biopolymer due to its abundance and biodegradability, although its poor mechanical and barrier properties limit direct application. In this study, OFIM-based films reinforced with cellulose nanofibers (CNF) and graphitic carbon nitride (g-C₃N₄) nanoparticles at 1%, 3%, and 5% were developed for food packaging applications. The g-C₃N₄ nanoparticles and OFIM/CNF/g-C₃N₄ composite films were characterized using UV-vis spectroscopy, XRD, and FTIR, confirming successful nanoparticle synthesis and incorporation into the biopolymer matrix. The nanocomposite films exhibited significantly improved physicochemical, mechanical, optical, and biological properties (p < 0.05). Increasing g-C₃N₄ concentration reduced moisture content, solubility, and water vapor permeability while enhancing tensile strength, thickness, and UV-blocking capacity, with optimal overall performance at 5% g-C₃N₄. Antioxidant activity increased with nanoparticle concentration, as demonstrated by ABTS radical scavenging assays. Antimicrobial evaluation against Enterococcus faecalis, Escherichia coli, and Staphylococcus aureus revealed enhanced inhibition, particularly at 3% g-C₃N₄, attributed to improved nanoparticle dispersion and bioactive compounds in OFIM. Overall, the OFIM/CNF/g-C₃N₄ nanocomposite films show strong potential as sustainable active food packaging materials, supporting reduced plastic use and postharvest losses in line with the Sustainable Development Goals.