Development and characterization of curdlan-based edible films with enhanced antimicrobial properties for Salmon preservation

Herein, an active curdlan-based edible film was successfully developed via an efficient solution casting method. The structural, physicochemical, and antimicrobial properties of the films were evaluated following the incorporation of six natural antimicrobial agents. Comprehensive characterization techniques, including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), light transmittance measurements, and X-ray diffraction (XRD), confirmed the robust film-forming capacity of the curdlan matrix. Among the tested additives, nisin proved the most effective, significantly improving the film's thermal stability and mechanical performance. The resulting CLGF-NISIN film demonstrated superior properties, achieving a tensile strength of 31.91 MPa, a Young's modulus of 1105.56 MPa, and an elongation at break of 16.51 %. Additionally, hydrophobicity was markedly enhanced, as indicated by a contact angle (CA) of 69.15°, water solubility (WS) of 21.64 %, and water vapor permeability (WVP) of 5.69 × 10⁻¹⁴ g·m⁻¹·s⁻¹·Pa⁻¹. Functionally, the films exhibited strong antimicrobial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). When applied to salmon fillets, the CLGF-NISIN film effectively preserved organoleptic qualities, inhibited lipid oxidation, and maintained microbial safety during refrigerated storage. Collectively, these findings underscore the potential of CLGF-NISIN films as a sustainable, and high-performance packaging solution for extending the shelf life of perishable seafood products.