Development of tea extracts and chitosan composite films for active packaging materials.

The effects of 0.5%, 1% and 2% green tea extracts (GTE) and black tea extracts (BTE) on the physical, structural and antioxidant properties of chitosan films were investigated. Results showed that the addition of tea extracts significantly decreased water vapour permeability and increased the antioxidant ability of films. The DPPH radical scavenging ability of GTE films was stronger than that of BTE films in all food simulants (0%, 20%, 75% and 95% ethanol). The equilibration time in different food simulants decreased with the increased ethanol concentration. DSC and FTIR spectra analysis indicated that there was strong interaction in film matrix, which could be reflected by the physical and mechanical properties of composite films. This study revealed that an active chitosan film could be obtained by incorporation of tea extracts, which may provide new formulation options for developing an antioxidant active packaging.