Enhancement of mechanical, barrier, and functional properties of chitosan film reinforced with glycerol, COS, and gallic acid for active food packaging

The demand for eco-friendly and natural food packaging materials has sparked considerable interest in the research and development of sustainable active packaging materials. In this study, a chitosan-based film was developed using glycerol as a plasticiser, chitooligosaccharide (COS) as an additive, and gallic acid as a cross-linking agent. The physical, barrier, mechanical, morphological, thermal, and functional properties of fabricated films were measured. The bio-composite film showed significantly lower moisture content (from 24.28 to 17.01%), water solubility (from 41.56% to 31.03%), water vapour permeability (14.63 to 9.79 × 10⁻⁹ gm⁻¹s⁻¹Pa⁻¹), and light transmittance (from 63.67% to 21.71%) compared to neat chitosan film. Furthermore, the bio-composite film exhibited higher tensile strength (57.66 MPa) and elongation at break (88.76%), smooth microstructure, strong DPPH and ABTS radicals scavenging capacity, and good antimicrobial activity towards E. coli, L. innocua, and S. cerevisiae, and non-toxic to HaCaT cells indicating promising potential for use in sustainable active food packaging.