Synergistic enhancement of functional properties in tea seed starch-based films incorporated with epigallocatechin gallate and chitosan

The growing demand for sustainable food packaging has spurred interest in starch-based films. In this study, tea seed starch-based films incorporating epigallocatechin gallate (EGCG) and chitosan were developed and systematically evaluated as potential food packaging materials. The film-forming solutions exhibited shear-thinning behavior, producing blend films with thicknesses ranging from 0.054 to 0.089 mm, and FTIR spectroscopy confirmed abundant non-covalent interactions among starch, EGCG, and chitosan. The microstructure showed aggregation and fracture in the cross-section of blend films containing EGCG and chitosan, but with reduced surface roughness. The color and optical tests demonstrated that EGCG significantly enhanced the UV-blocking property of the film, while chitosan primarily influenced its apparent color and transparency. Adjusting the EGCG/chitosan ratio effectively modulated the film's hydration and surface properties, leading to markedly improved tensile strength (from 3.11 MPa to 16.28 MPa) and elongation at break (from 71.10% to 109.40%). Further study confirmed that the blend film exhibited slow release of EGCG and desirable antioxidant properties in both aqueous and ethanol media, features that could effectively prevent fruit browning. These findings indicate the potential of tea seed starch-based films functionalized with EGCG and chitosan as promising active packaging materials for food preservation.