Investigation of film Physical properties under various starch thermal treatments with emphasis on Retrogradation effects

This study investigated the changes in the physical properties of cornstarch-based films as they were retrogradely aged at different temperatures. Using a casting method, the films were fabricated, and their effects on the mechanical properties, thermal stability, barrier properties, and essential properties were analyzed. With prolonged aging and retrogradation periods, reductions in film thickness, solubility, water content, and water vapor permeability of 5.35%, 9.92%, 29.61%, and 20.94%, respectively, were observed. In addition, the surface roughness decreased by 44.46% for Rq (root-mean-square roughness) and 45.61% for Ra (arithmetic average roughness), while the elongation at break decreased by 72.64%. Conversely, the tensile strength, maximum degradation rate, and maximum degradation temperature increased by 116.98%, 99.5%, and 3.21%, respectively. These results provide a fundamental understanding of the changes that occur in the properties of cornstarch-based films during aging and retrogradation.