Antibacterial and Structural Properties of Chitosan-Gelatin Edible Films Enhanced with Liquid Smoke from Rice Husks and Cajuput Twigs

This study developed edible films incorporating liquid smoke derived from rice husks and cajuput twigs as both a chitosan solvent and an active antimicrobial–antioxidant agent. The fabricated films exhibited excellent mechanical integrity in accordance with Japanese Industrial Standards and possessed homogeneous microstructures, as evidenced by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analyses. Antibacterial tests demonstrated that higher concentrations of chitosan and liquid smoke enhanced inhibition against Escherichia coli and Bacillus subtilis, with inhibition zone diameters ranging from 6.08 mm to 11.68 mm for E.coli and 6.05 mm to 9.18 mm for B.subtilis. Antibacterial activity against Bacillus subtilis was enhanced in edible films containing rice husk and cajuput twig liquid smoke, with increases observed alongside rising concentrations of the liquid smoke. These results suggest that liquid smoke derived from biomass enhances the mechanical and antimicrobial properties of edible films, rendering them an eco-friendly and sustainable packaging solution.