Hydrophobic bioactive diaporthein B regulates supramolecular hydrogel formation for controlled release and postharvest fruit preservation.

Abstract

Low-molecular-weight hydrogels (LMWHs) show promise for bioactive delivery but are limited in food systems by high gelation thresholds and poor incorporation of hydrophobic compounds. Here, a food-grade supramolecular hydrogel based on glycyrrhizic acid (GA) was developed, in which a marine-derived natural product, diaporthein B (DTB), actively participated in network formation rather than acting as passive cargo. DTB enhanced non-covalent interactions, lowered the critical gelation concentration from 15 mM to 10 mM (a 33.0% reduction), and enabled stable network formation at low loading. The resulting hydrogel exhibited improved viscoelasticity, pH-responsive swelling, and sustained release behavior. It also showed enhanced antifungal activity against Botryosphaeria dothidea and prolonged efficacy compared to free DTB. In the postharvest apple model, the system effectively suppressed disease progression and preserved fruit quality. This work demonstrates a strategy for integrating hydrophobic bioactives into food-relevant networks without chemical modification or surfactants.