Preparation and characterization of tea polyphenols-chitosan-based nanoparticles and their application in starch films

Abstract

Green composite starch films were prepared using tea polyphenols-chitosan-based nanoparticles as active agent and nanocellulose as strength agent, which showed good mechanical and antioxidant activities and is a candidate for food packaging in this work. Here, chitosan-based nanoparticles containing tea polyphenols (CNTP) were prepared by the ionic gel method. The best utilization of tea polyphenols could be achieved when the mass ratio of tea polyphenols to sodium tripolyphosphate was 3:1, the concentration of tea polyphenols was 0.01 g/mL, and the pH of chitosan solution was 4. Uniform and stable CNTP with a particle size of approximately 200 nm was prepared. CNTP release rates were 45.9% after 6 h, showing the ability to release slowly. Using starch as the substrate, nanocellulose as the enhancer, and tea polyphenols as the antioxidant and antibacterial agent, an active film was prepared that demonstrated improved transparency, mechanical properties, and antioxidant and antibacterial activity. Its transmittance reached 83.9%, and the tensile strength was 33.4 MPa. The scavenging efficiency of 2,2-diphenyl-1-picrylhydrazyl (DPPH) by the composite film was 42%, and the OD value of the composite film was 0.9348. The results showed that CNTP can prolong the release period and activity of tea polyphenols, and the composite film with CNTP had antibacterial and antioxidant activities to prolong the shelf life of food.