Mechanistic insight into the bridging–locking assembly of an ovalbumin–konjac glucomannan hydrogel for resveratrol delivery

Abstract

Protein–polysaccharide hydrogels with clear gelation mechanisms and gastrointestinal robustness are attractive carriers for hydrophobic nutraceuticals. Here, a hydrogel composed of ovalbumin (OVA), konjac glucomannan (KGM), and genipin (GP), hereafter referred to as the OVA–KGM–GP hydrogel, was developed and found to form a self-supporting gel at room temperature. Apparent thermokinetic fitting provided an early clue that the OVA–KGM–GP system exhibited an integrated dehydration-stage signature rather than a simple additive thermal response, with ΔS^‡ values of −77.03 J mol⁻¹ K⁻¹ for OVA–KGM–GP and −88.55 J mol⁻¹ K⁻¹ for OVA–GP. Multiscale characterization further demonstrated that KGM guided OVA pre-assembly into interconnected structures, while GP fixed and compacted these structures into junction-like domains, yielding a hierarchically integrated lamellar–honeycomb network with elastic-dominant behavior. The hydrogel also exhibited enhanced gastric resistance, evidenced by a lower free amino group content after 2 h of simulated gastric digestion. As a delivery matrix, the hydrogel achieved a resveratrol encapsulation efficiency of 98.23%, and the bioaccessibility after 4 h simulated gastrointestinal digestion reached 70.23%, nearly two-fold that of free resveratrol (35.78%). These results support a bridging-locking assembly pathway for gelation and highlight its potential for hydrophobic nutraceutical delivery.