Sustainable Starch-based Films from Sweet Potato and Arrowroot: Functional Enhancement through Gallic Acid and Aloe Vera Reinforcement

This study investigated the yield, functional properties and film-forming behavior of native and gallic acid (GA)-modified starches from sweet potato (Ipomoea batatas) and arrowroot (Maranta arundinacea). GA modification induced structural deformation and significantly reduced starch moisture content while enhancing solubility, swelling power and waterholding capacity. Bulk density declined correspondingly. Twelve starch-based films were prepared using glycerol and aloe vera, as additives, with formulations containing native starches (unmodified), GA-modified starches or direct incorporation of GA during film preparation. Moisture content of films ranged from 0.025–0.142%, with GAmodified starch films showing the lowest values. Direct GA incorporation increased film thickness and solubility, whereas GA-modified starch films exhibited lower solubility in water, ethanol and chloroform, suggesting enhanced stability. Light transmittance was highest in native starch films but decreased in GA-containing films, reflecting denser phenolic-rich networks. Importantly, antioxidant assays revealed that GA-enriched films exhibited strong DPPH radical scavenging activity (up to 92.1%), compared with moderate activity in GAmodified films and negligible activity in native starch films. These results demonstrate that GA improves both the functional properties and the structural and antioxidant performance of starch and starch-based films. The dual benefits highlight GA-starch films as promosisng candidates for biodegradabel active packaging and pharmaceutical protective materials where controlled oxygen-scavenging functionality is critical.