Novel dual-crosslinked antimicrobial hydrogels of oxidized hyaluronic acid/gelatin grafted with curcumin-Zn2+ complexes for preservation of chilled chicken

To enhance the solubility and stability of curcumin, a novel double-crosslinked antimicrobial hydrogels OHA/GEL/CUR-Zn(II) was prepared. Curcumin, as a ligand, was complexed with Zn 2+ to form a stable complex (CUR-Zn(II)), which was grafted to the hydrogel formed by oxidized hyaluronic acid (OHA) and gelatin (GEL) through Schiff base reaction. Fourier transform infrared spectroscopy analysis was employed to determine the formation of Schiff base (C N) between OHA with GEL, as well as the ester bond between OHA with CUR-Zn(II). X-ray diffraction results showed the presence of amorphous peaks in the composite film. The change in crystal structure was probably due to the formation of new hydrogen bonding or chemical bonding between CUR-Zn(II) and OHA/GEL. The incorporation of CUR-Zn(II) complexes into a hydrogel matrix resulted in a significant enhancement of tensile strength (TS) and elongation at break, accompanied by a reduction in water vapor transmission rate. Meanwhile, the hydrogel achieved a bactericidal rate of over 99 % against the predominant spoilage bacteria Escherichia coli and Staphylococcus aureus in chilled chicken meat, extending the shelf life of the chilled chicken meat to over 8 days. Overall, the composite hydrogel enhanced the stability of curcumin by chelating it with Zn 2+ and increased its solubility by grafting it onto OHA and GEL cross-linked hydrogels, demonstrating significant application potential in food packaging.