Biodegradation, Water Sorption Isotherms and Thermodynamic Properties of Extruded Packaging Composed of Cassava Starch With Tomato Peel

Abstract Scientists are developing new technologies for biodegradable active packaging made from natural polymers and antioxidant agents as a more sustainable alternative to conventional packaging made from fossil fuels. In this study, the biodegradation of the films was evaluated using techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), visual and morphological analysis using scanning electron microscopy (SEM). Water sorption isotherms and thermodynamic parameters were analyzed at different temperatures (5 °C, 15 °C, and 25 °C) and relative humidities until the samples reached a constant weight. The results showed changes in the morphology, color, and mass of the cassava starch films with tomato peel due to biodegradation. FTIR revealed structural changes in the films, while TG/DTG curves did not show significant differences over time. The addition of tomato peel to the polymer matrix resulted in lower water solubility. The Guggenheim-Anderson-de Boer (GAB) model provided the best fit for the water sorption isotherms. The monolayer moisture content (X m ) increased with temperature, indicating the availability of active sites for water sorption in the material. Thermodynamic analyses indicated that lower moisture content corresponded to more active sorption sites, and the sorbed water molecules exhibited greater order. In conclusion, biodegradable active packaging offers an environmentally friendly alternative as it decomposes more rapidly than conventional packaging made from fossil-derived materials. The sorption isotherms demonstrated that the adsorption in the packaging materials is controlled by entropy, emphasizing the importance of the number of available active sites for binding rather than the chemical composition of the film.