Development of Epigallocatechin-Loaded Water Caltrop Starch Aerogels: Structure, Functional Properties and In Vitro Release Behavior

The increasing demand for sustainable food packaging has generated interest in biodegradable carriers for bioactive chemicals. This study created porous aerogels from water caltrop starch (WCS) to encapsulate and regulate the release of epigallocatechin (EGC), a sensitive natural polyphenol. WCS aerogels with different EGC concentrations (0.6–2.5 g per 2.5 g starch) were produced using sol–gel processing and freeze-drying. Structural investigations (FTIR, XRD) suggested bonding interactions between WCS and EGC, which stabilized the polyphenol and affected crystallinity. Scanning electron microscopy demonstrated that an appropriate EGC loading (1.8 g) facilitated a well-connected porous network, improving water and oil retention. Rheological and textural investigations demonstrated that the addition of EGC enhanced the gel network, leading to increased mechanical properties. In vitro release tests revealed a sustained, diffusion-controlled release profile over 10 days, with higher EGC loading resulting in enhanced retention. The aerogels demonstrated concentration-dependent antibacterial efficacy against E. coli and S. aureus, and exhibited preliminary degradability in soil and water. These findings suggest that WCS-based aerogels represent a potential biodegradable delivery system for polyphenols, demanding additional research for functional food packaging.