Microstructural and physical properties of alkali-neutralization curdlan/gelatin blended edible coatings and films

The aim of this study was to develop blended coating and packaging films with enhanced properties by adjusting the blending ratio of alkali-neutralization curdlan (ANCUD) and G, and systematically investigated how changes in the ratio affect their structure and functionality. The CLSM results showed that ANCUD and G were compatible in the blended system. Rheological data revealed that as the ANCUD ratio in the blended coating increased the rheological properties were significantly improved. Notably, the coating with a G/ANCUD ratio of 3:7 exhibited excellent film-forming properties. The addition of ANCUD significantly enhanced the UV-blocking ability, crystallinity, and thermal stability of the G film. Compared to the G film, the elongation at break of the G/ANCUD (3:7) film increased by a factor of 3.33, while its water solubility decreased by 27.37 %. SEM observations revealed that the cross-sectional structure of the G/ANCUD (3:7) films displayed fibrous, tightly bound cross-linking characteristics. FTIR and TGA results further indicated strong hydrogen bonding interactions between G and ANCUD, and that the incorporation of ANCUD promoted the transition from β-sheet to α-helix in the gelatin conformation. Our study suggests that the G/ANCUD (3:7) blended coating/packaging film holds promising potential for use as a food packaging material.