Antioxidant activity and physicochemical properties of chitosan films incorporated with Lycium barbarum fruit extract for active food packaging

Active packaging film was developed by incorporating Lycium barbarum fruit extract (LFE) into chitosan. The effects of LFE on physicochemical properties of the chitosan/LFE films were evaluated. When the weight ratio of LFE to chitosan was increased from 0:1 to 1:1, DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity of the chitosan/LFE films increased near ten-folds and reached up to 35.8%; water vapour permeability of the chitosan/LFE films decreased 43.0% from 5.67gmmm(-2)day(-1)kPa(,)(-1) and water solubility decreased from 100% to 24.52% because of interactions between LFE and hydrophilic groups of chitosan confirmed by FTIR. However, the chitosan/LFE films became darker after LFE was incorporated. The pure chitosan film showed better tensile strength (23.19MPa) and elongation at break (22.29%) than the chitosan/LFE films (15.52MPa and 9.58% for the one with weight ratio of LFE to chitosan of 0.6:1).