Abstract: Using sodium alginate (SA) and chitosan (CS) as film-forming substrates and different concentrations (0%, 1%, 2.5% and 5%) of tea polyphenol (TP) @ zeolitic imidazolate framework-8 (ZIF-8) nanocomposites as a functional component, TP@ZIF-8/CS/SA composite membranes were prepared by layer-by-layer self-assembly. The morphology and composition of the composite films were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, texture analyzer and color different meter. The results showed that addition of TP@ZIF-8 nanomaterial at 5% changed the color, affected the microstructure, and enhanced the thermal stability, barrier performance, and mechanical properties of the composite films. In addition, addition of TP@ZIF-8 nano-composite imparted good antioxidant and antibacterial activity the composite films. Thus, the biodegradable composite active packaging films have good prospects for application in the field of food preservation.

Key words: tea polyphenol; chitosan; sodium alginate; antioxidant activity; antibacterial activity