Collagen films functionalized with gallic acid in the presence of laccase for beef preservation

Collagen films were functionalized with different concentrations of gallic acid (GA) in the presence of laccase. FTIR results suggested that crosslinking bonds formed between the amino groups of collagen and quinone radicals generated from the oxidized phenolic hydroxyl groups of GA by laccase. The amount of cross-linking gradually increased with increasing GA concentration. The formed covalent cross-linking bonds strengthened the combination between collagen and GA, improving the stability of GA in the film matrix. The tensile strength and denaturation temperature of collagen film was increased by 43.01 MPa and 17.9 °C, respectively, at GA concentration of 8 mmol. When GA concentration was ≥ 4 mmol, the films exhibited obvious scavenging activity against DPPH free radicals and antibacterial activities against S. aureus and E. coli . Film with 8 mmol GA could reduce the thiobarbituric acid reactive substance values, total viable count and total volatile basic nitrogen content of beef during storage, showing a good application potential in food packaging.