Preparation and characterization of active films based on chitosan incorporated tea polyphenols

Active films based on chitosan incorporated tea polyphenols with different concentrations were developed. Attenuated total reflectance Fourier transform infrared spectrometry was used to investigate the potential interactions between chitosan and tea polyphenols in the films. Physical properties of the chitosan films incorporated tea polyphenols, including density, moisture content, opacity, color, water solubility and water vapor permeability, were measured. Antioxidant activity of the films was characterized in terms of total phenolic content and 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity. The results indicated that the incorporation of tea polyphenols caused interactions between chitosan and tea polyphenols and gave rise to the films darker appearance. After the addition of tea polyphenols, the films showed increased water solubility and decreased water vapor permeability. Meanwhile, the incorporation of tea polyphenols enhanced the total phenolic content and 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity of the films, i.e., increased the antioxidant activity of the films. But the antioxidant activity of the chitosan films incorporated tea polyphenols declined with time. (c) 2012 Elsevier Ltd. All rights reserved.