Biological properties of chitosan edible films incorporated with different classes of flavonoids and their role in preserving the quality of chilled beef

Chitosan based bioactive films incorporated with catechin (CH), quercetin (QDH) and luteolin (LU) at 1, 3, 5 and 10% (w/w of chitosan) were prepared and their biological properties were evaluated. Additionally, the ability of the composite films to improve the shelf life and quality of beef was evaluated during storage at 4 °C for two weeks. Antioxidant activity of the composite films increased along with total phenolic and total flavonoid contents (TPC and TFC). All three films inhibited the growth of Listeria monocytogenes, Salmonella typhimurium, Escherichia coli and Staphylococcus aureus under the contact surface of the film when tested in agar plates. Storage of the chitosan films at room (21 °C) and cold (4 °C) temperatures for six weeks resulted in significant reductions in the TPC, TFC and antioxidant activity of the films, and the reduction rate was higher at room temperature. During the two weeks storage the color of the beef was maintained, and the aerobic plate count remained low. The results demonstrated that chitosan composite films prepared with all three flavonoids could be used to improve the shelf life and color quality of beef without the addition of synthetic preservatives.