Characterization of hydrophobic modification of gelatin crosslinked vanillin edible coatings and its application in food preservation

Conventional petroleum-based food packaging faces sustainability challenges due to limited water resistance and mechanical strength. To address this, we developed an octenyl succinic anhydride (OSA)-modified gelatin film crosslinked with vanillin (OGV), enhancing its potential for food packaging applications. Infrared and X-ray spectroscopy confirmed the successful modification of gelatin and forming a Schiff base structure with vanillin. Thermal analysis showed that the modification and crosslinking enhanced the film's thermal stability. The results demonstrated that OSA modification and vanillin crosslinking significantly enhanced the mechanical strength of OGV films, increasing tensile strength from 19.50 MPa to 43.04 MPa. Additionally, OGV films exhibited excellent water vapor barrier properties, with the water contact angle increasing from 76.6° to 91.1°, along with superior UV-blocking capacity and notable antimicrobial activity against E. coli and S. aureus . Furthermore, applying OGV films to fresh-cut green peppers effectively reduced weight loss (by 9.23 % after 10 days), preserved chlorophyll and ascorbic acid content, and inhibited lipid peroxidation, thereby extending shelf life. These findings highlight the potential of this bio-based film as an effective and sustainable alternative for food packaging applications.