Development and Physicochemical Characterization of Chitosan– <i>Pedalium murex</i> Linn. Mucilage Bioactive Films for Postharvest Quality Improvement of Fresh Tomatoes

The current study aims to develop a novel alternative to synthetic food packaging films through a bioactive, eco-friendly, edible film that incorporates Pedalium murex Linn. mucilage (PMM) at varying concentrations (1–3%) into a chitosan (CH) matrix. PMM incorporation significantly decreased the water solubility and opacity of CH films. Comprehensive physicochemical characterizations of CH-PMM films’ thermal gravimetric analysis (TGA), DSC, FTIR, XRD, and SEM confirmed the thermal stability (Tmax 315 °C) and structural compatibility (CI 33–35%). The CH-PMM (3%) formulation exhibited superior antioxidant activity (71.69 ± 0.21%) and strong antibacterial efficacy against Escherichia coli (inhibition zone of 23.25 ± 0.19 mm), markedly outperforming plain CH films (15.9 ± 0.28 mm). It also demonstrated the maximum tensile strength of 7.50 ± 0.09 MPa and an elongation at break of 82 ± 0.07%. The optimized CH-PMM composite film formulation extended the postharvest shelf life of tomatoes by 20 days, providing a biodegradable and sustainable solution for postharvest quality preservation.