Development of an Active Crosslinked Nanocomposite Film Based on Gelatin-Ethyl Cellulose, Trans-Cinnamaldehyde, and Silver Nanoparticles for the Preservation of Sliced Meat

This study aimed to develop a novel bioactive biobased packaging film combining gelatin (G) and ethyl cellulose (EC), cardanol and glycerol as plasticizers, trans-cinnamaldehyde (TCA) as a crosslinker/bioactive compound, and silver nanoparticles (AgNPs) as bioactive agents. The degree of crosslinking, mechanical and thermal properties, water solubility (WS), and water vapor permeability (WVP) of the films were analyzed. Molecular interactions within the film matrix were determined by FTIR spectroscopy. The G-EC film, in a 1:2 weight ratio, exhibited improved physicochemical properties compared to the pure G film, with a low WS (7.8%). The incorporation of TCA and AgNPs—to form bioactive nanocomposite films—improved the barrier and mechanical properties of the film (WS 0.33%, WVP 2.39 g·mm·m⁻²·day⁻¹·kPa⁻¹, tensile strength 9.6 MPa) with a 57% degree of crosslinking. Thermal analyses (TGA/DSC) revealed improved thermal stability of these films, with an increase in the maximum decomposition temperature (T_max up to 370°C–380°C) and the glass transition temperature (T_g 29.5°C) after incorporation of TCA and AgNPs. FTIR analysis confirmed the amide/imine covalent crosslinking reaction between TCA and G, and polymer network stabilization by hydrogen bonding between G and EC. The nanocomposite films demonstrated effective in vitro antibacterial activity against pathogenic and spoilage bacteria, with an inhibition spectrum of 27%–54%. An in situ test performed on chilled sliced meat packaged in nanocomposite films showed a significant extension of its shelf-life, up to 9 days. These results highlight the potential of G-EC-TCA-AgNPs films as a sustainable packaging solution for improved meat preservation. Practical Applications: G-EC-TCA-AgNPs films developed in this study could be applied as bioactive and biobased food packaging films to extend the shelf-life of meat products. Films are made of biopolymers and address the challenges of sustainability and circular economy. TCA and AgNPs could be used as a synergic antimicrobial combination encapsulated in films to prevent the growth of pathogenic and spoilage microorganisms in meat.