Effects of Adding Sorghum Procyanidins on the Structure, Molecular Interactions, and Thermal Properties of Agar-Glycerol-Gelatin Films

Abstract

Films made with blends of agar and gelatin are usually unstable in aqueous environments and susceptible to temperature, so modifying these films with the addition of compatible compounds is necessary to improve their structural stability, properties, and potential uses. This work determined the effects of adding sorghum procyanidins on the structure, molecular interactions and thermal properties of agar-glycerol-gelatin films. Films were prepared by solution cast method and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and computational methods. Adding sorghum procyanidins to agar-gelatin films plasticized with glycerol produced significant modifications compared to control films. They contributed to the amorphous character and roughness of these films and the film’s microstructure, reducing weight loss and enhancing thermal stability. The predominant interactions among the film components were hydrogen bonds, van der Waals, and [Formula: see text]–[Formula: see text] interactions.