Bioactive nanocomposite zein-HPMC films incorporating green-synthesized silver nanoparticles from date seed extract for sustainable food preservation

Abstract

This work explores the development and characterization of multifunctional biopolymer films based on zein-HPMC integrating date seed extract (DSE) and the AgNPs, and their application as coatings for date fruits and pastries preservation. Biosynthesized AgNPs were incorporated into the films at concentrations from 0 to 0.025%. The resulting films were characterized in terms of structural, functional and physical properties. AgNP-DSE composite film with 0.025% AgNPs exhibited 48.6% and 34.4% reduction in water vapor permeability and solubility, respectively, and a 38.2% increase in contact angle, demonstrating enhanced barrier properties and surface compactness. The molecular docking study supported favorable nanocomposite film matrix. The AgNP-DSE films containing 0.025% AgNPs were the best multifunctional food packaging system due to their excellent mechanical, barrier and biological properties, ensuring safety and performance. The optimized AgNP-DSE coating effectively preserved color, reduced oxidative degradation, moisture loss, and maintained structural integrity in date fruits and pastries during storage (p < 0.05). Coated date fruits and pastries retained 72.7% and 73.8% of their initial firmness, with lipid oxidation reduced by 46.2% and 40% after 56 and 28 days, respectively, compared to controls. Fungal growth of Aspergillus flavus was suppressed by over 70% in coated samples (p < 0.05), confirming the synergistic antimicrobial effect of AgNPs and DSE. The antifungal activity was further highlighted via docking simulations of polyphenols-capped AgNPs with two key fungal enzymes, revealing strong binding energy and mechanistic insights into enzyme inhibition. This highlights a nanotechnology-based approach for extending food shelf life, reducing waste, and advancing bio-based active packaging solutions.