Development and characterization of biodegradable chitosan films incorporating olive and pomegranate leaf extracts for active food packaging

This study developed biodegradable chitosan films incorporating optimized olive ( Olea europaea ) and pomegranate ( Punica granatum ) leaf extracts to improve functional properties for active food packaging. Films were prepared at extract concentrations of 100, 300, and 500 µg/mL, including binary mixtures, and compared to an extract-free control. Unlike previous studies that typically focus on single plant sources or peel-derived phenolics, this work employs leaf extracts from two species and systematically contrasts single and combined formulations at multiple concentrations within the same chitosan matrix, providing a more comprehensive evaluation of structure–function relationships in active films. Elevated extract levels significantly decreased water vapor permeability and solubility, with the lowest solubility in the 500 µg/mL pomegranate extract film. Moisture content showed no significant change ( p > 0.05), while water absorption increased progressively over six days of storage. Mechanical analysis revealed reduced tensile strength but enhanced elongation at break and thickness with higher extracts. SEM imaging displayed irregular, porous microstructures, and antimicrobial assays demonstrated potent inhibition against Salmonella Typhi . The 500 µg/mL pomegranate extract formulation exhibited optimal performance, highlighting its potential as a novel, leaf-extract-based system for sustainable active packaging applications.