Green-Synthesized Silver Nanoparticle-Loaded Antimicrobial Films: Preparation, Characterization, and Food Preservation

This study presented a novel antimicrobial packaging PVA/xanthan gum film decorated with green-synthesized silver nanoparticles (AgNPs) derived fromMyrica rubra leaf extract(MRLE) for the first time. Montmorillonite (MMT) was used to improve its dispersion (AgNPs@MMT). The synthesis time, temperature, and concentration of AgNO3were considered using a central composite design coupled with response surface methodology to obtain the optimum AgNPs (2 h, 75 °C, 2 mM). Analysis of substance concentration changes confirmed that the higher phenolic and flavonoid content inMRLEacted as reducing agents and stabilizers in AgNP synthesis, participating in the reaction rather than adsorbing to nanoparticles. TEM, XRD, and FTIR images revealed a spherical shape of the prepared AgNPs, with an average diameter of 8.23 ± 4.27 nm. The incorporation of AgNPs@MMT significantly enhanced the mechanical properties of the films, with the elongation at break and shear strength increasing by 65.19% and 52.10%, respectively, for the PAM2 sample. The films exhibited strong antimicrobial activity against bothEscherichia coli(18.56 mm) andStaphylococcus aureus(20.73 mm). The films demonstrated effective food preservation capabilities, significantly reducing weight loss and extending the shelf life of packaged grapes and bananas. Molecular dynamics simulations reveal the diffusion behavior of AgNPs in different matrices, while the measured silver migration (0.25 ± 0.03 mg/kg) complied withEFSAregulations (10 mg/kg), confirming its food safety. These results demonstrate the film’s potential as an active packaging material for fruit preservation.