Optimization and release evaluation for tea polyphenols and chitosan composite films with regulation of glycerol and Tween

In order to optimize the performance of chitosan-tea polyphenols composite films, effects of glycerol and Tween on the antioxidative activities and physical performance of chitosan composite films were evaluated. The results indicated that both flexibility and water vapour permeability of chitosan/tea polyphenols films were improved with the addition of glycerol, meanwhile the solubility and swelling degree decreased. Moreover, the release time of antioxidants from films was delayed with the addition of glycerol. The presence of Tween 20 had no significant effect on the tensile strength of films, but changed the DPPH radical scavenging activity depending on the blend ratio of glycerol and Tween. DSC, FTIR and X-ray analysis showed strong interaction among chitosan, tea polyphenols, glycerol and Tween. The optimum ratio was 0.5% tea polyphenols, 1.2% glycerol and 0.1% Tween. This study provided a reference that an optimized chitosan/tea polyphenols composite film could be obtained by the regulation of glycerol and Tween.