Enhancement of Thermal Sealing and Solubility Properties of Konjac-Glucan/Gelatin Films by Hydroxypropyl Cassava Starch Thermoplastic Effect

The burgeoning convenience food sector, particularly in China, has intensified demand for packaging that simultaneously delivers convenience, environmental sustainability, and functional performance. This study addresses this need by developing a novel self-sealing, rapidly soluble food packaging film. The film was prepared using solvent casting technology, with a konjac glucomannan (KGM) matrix as the base material and gelatin (Gel) and hydroxypropyl tapioca starch (HS) as reinforcing agents. Leveraging the thermoplastic effect of HS (its hydroxypropyl side chains disrupt the ordered hydrogen bond network of KGM and Gel, enhancing molecular chain mobility) characterization via FTIR and SEM confirmed successful heat-sealing upon HS incorporation, while dissolution testing validated enhanced dissolution kinetics. The optimal formulation (KGH3) exhibited superior mechanical properties (tensile strength (TS): 17.54 MPa) and excellent barrier performance against both light and oxygen transmission compared to pristine KGM and KG control films. Self-sealed pouches fabricated from KGH films preserved edible oil for 65 days, maintaining peroxide values within acceptable limits and demonstrating 48.7% reduction in oxidation compared to KG films. These findings establish KGM–Gel–HS film as promising candidates for adhesive-free, biodegradable packaging of lipid-rich foods.