Development of antibacterial and antifouling bio-based food packaging films using zwitterionic rosin-modified chitosan

This study focuses on enhancing the antibacterial and self-cleaning properties of bio-based food packaging films. We developed a zwitterionic rosin sulfonated betaine (MPA-BN + SO 3 − ) and co-grafted it with rosin quaternary ammonium salt onto chitosan, which was then combined with gelatin to create the films. Characterization was done using FTIR and 1 H NMR. The films exhibited a minimum inhibitory concentration (MIC) of 200 μg/mL for Staphylococcus aureus and 400 μg/mL for Escherichia coli , with a 19 mm antibacterial zone for 30% CS-B-S in Staphylococcus aureus . The modification improved water solubility, tensile strength (10.22 MPa, a 20% increase), elongation at break (87%), and antioxidant properties (48.2%). Preservation tests on fresh fruits and biological safety assessments through cytotoxicity tests and a 30-day gastric lavage experiment in mice confirmed the effectiveness and safety of films. Outdoor degradation tests showed strong biodegradability and minimal environmental impact. These results suggest that the CS-B-S/gelatin film is a promising food packaging material with excellent antibacterial, antifouling, and biodegradable properties.