Mutual interactions between HG-LG gellan gum and tea polyphenols: Concentration-dependent structural modulation and...

Tea polyphenols (TPs) provide health benefits but are unstable during the thermal and pH variations during food processing and storage. In this study, we developed a composite hydrogel system using low- and high-acyl gellan gums (HG-LG, 1:1 w/w) for efficient TP protective matrix. The characteristics were systematically evaluated. Incorporating TPs enhanced the gel texture and water retention but increasing the TP content led to a decrease in the storage and loss moduli and texture parameters. Analyses confirmed the formation of a stable, hydrogen bonded 3D network. Molecular dynamics simulations further revealed that TPs, in particular epigallocatechin gallate, interact strongly with gellan gum through multiple hydrogen bonding and electrostatic interactions, stabilizing the compounds and enhancing thermal stability. The gels retained over 90% DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity following prolonged heating, demonstrating enhanced stability. Thus, the HG-LG composite hydrogel is an effective, thermally stable carrier for TPs in functional food applications.