Development and characterization of starch–gelatin edible films reinforced with lemon peel and pomegranate peel powders

The development of sustainable alternatives to petroleum-based food packaging has increased interest in biodegradable edible films derived from renewable resources. In this study, powdered lemon ( Citrus limon ) and pomegranate ( Punica granatum ) peels were directly incorporated into starch gelatin matrices to produce edible films through a simple waste valorization approach. The effects of peel type on the morphology, water holding capacity, and mechanical behavior of the films were comparatively investigated. The pomegranate peel-reinforced films exhibited higher load-bearing capacity, whereas the lemon peel-reinforced films showed higher water holding capacity and greater flexibility. Scanning electron microscopy revealed distinct morphological differences between the two formulations, with the lemon peel-reinforced film exhibiting a relatively rougher and more heterogeneous surface, while the pomegranate peel-reinforced film displayed a comparatively smoother and more continuous morphology. These morphological differences were consistent with the observed differences in hydration and mechanical behavior. Overall, the findings demonstrate the potential of whole fruit peel powders as sustainable bio-based reinforcements for starch–gelatin edible films and highlight their potential for biodegradable food-packaging applications.