Eco-Friendly Chitosan-Pectin Polyelectrolyte Films for Sustainable Food Packaging: Performance and Functional Properties

Polyelectrolyte complexes (PECs) are recognized as promising materials for the development of sustainable food packaging. In this study, eco-friendly PECs based on pectin (P) and chitosan (C) were prepared by solvent casting at different pH values and volume ratios (C, P, 1C:1P, 1C:2.5P, and 1C:5P) (v/v). The resulting films were characterized for numerous features, including thickness, opacity, moisture content, swelling degree, and water solubility, while mechanical performance (elongation at break and tensile strength), water vapor transmission rate (WVTR), surface energy, and anti-adhesive activity were evaluated for the most promising formulation. The results revealed that blending chitosan with pectin significantly improved the films’ physicochemical properties, notably by increasing thickness (up to 100 µm) and opacity (slightly above 2) while reducing the swelling degree (from over 1800% for pure chitosan to below 600% for 1C:2.5P film at pH 3.2) and the water solubility (from 100% for pectin films to around 45–50% for the blended films). The film 1C:2.5P at pH 3.2 showed improved barrier performance, with a lower WVTR (approximately 20 g/h·m2) compared to the single polymer films (more than 30 g/h·m2), and exhibited significant anti-adhesive activity by reducing bacterial adhesion to below 5% compared to 65% for the conventional packaging film. However, these improvements were accompanied by reduced tensile strength (From ~4.2 MPa to ~1.3 MPa) and in elongation at break (from ~50% to ~20%). Overall, PEC films demonstrate strong potential as sustainable packaging materials by combining improved barrier properties and anti-adhesive activity, despite some limitations in mechanical resistance.