Physicochemical Characterization and Biodegradability of Nanostructured Chitosan-Based Films Reinforced with Orange Waste

The valorization of agricultural by-products through their integration into biodegradable materials represents a promising approach for sustainable food preservation. In this study, nanostructured chitosan/polyvinyl alcohol (PVA)/orange peel–bagasse waste (OPB) (0.125%, 0.25%, and 0.5% OPB) films were developed and characterized for their physicochemical, mechanical, and biodegradation properties. Scanning electron microscopy and confocal laser scanning microscopy revealed that OPB concentration influenced structural homogeneity. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) revealed possible molecular interactions among components through hydrogen bonding (peaks at 1570, 1416 cm−1, and 1020 cm−1) and imine (C = N) formation (broadening of the peak at 1425 cm−1). As OPB increased, water vapor diffusion and film rigidity increased, while elongation at break decreased. After composting, weight loss was 93.7% and 100% for the chitosan and PVA films, respectively. For the nanostructured films, weight loss was between 94.7% (30PVA/0.5OPB) and 99.7% (30PVA/0.125OPB). Regarding ATR-FTIR of the blends, the intensity of the peaks located between 3625 and 3005 cm−1, at 2919 cm−1, at 1729 cm−1, at 1621 cm−1, at 1521 cm−1, and between 1160 and 885 cm−1, corresponding to the OPB functional groups, decreased. These results demonstrate that incorporating citrus waste enhances biodegradability and provides films barrier properties suitable for fresh produce preservation.