<p>The objective of this study was to evaluate the effect of grape polysaccharide content on the biodegradable polymeric films derived from cornmeal flour starch properties. The physicochemical and thermal characteristics of starch films containing 5%, 10%, and 15% grape-derived polysaccharides were investigated. The experiments showed that the addition of 5% polysaccharides improved water solubility by 14.18% compared to the control film, whereas increasing the polysaccharide content to 10% and 15% resulted in decreases of 2.11% and 4.07%. Nevertheless, high polysaccharide concentration resulted in increased swelling index and thermal stability. The maximum decomposition temperature rose from 319.50 °C for samples with 5% polysaccharides to 328.33 °C for those with 15% polysaccharides, while the swelling index increased from 70.08% in the control sample to 122.04% in the sample with 10% polysaccharides. To identify the decomposition mechanism for each degradation stage, the Coats-Redfren analysis was carried out. The data suggests that the thermal decomposition of films with polysaccharides involves three-dimensional diffusion for first degradation step, indicating low volatile compounds in the samples’ structure. The second degradation stage corresponds to the first order reaction, probably due to internal carbon rearrangement in the chemical structure. To calculate the apparent activation energies, model-free and nonlinear estimation methods were employed.</p>