Structurally optimized photo-crosslinkable casein-PEG hydrogels for enhanced encapsulation and functional stability of resveratrol.

Casein-based gel delivery systems often exhibit limited loading efficiency and functional performance under conventional formulation approaches. We present a novel UV-induced photo-crosslinking strategy for generating porous casein-polyethylene glycol gels, enhancing resveratrol stabilization and enabling controlled delivery during processing and storage. Structural characterization by FTIR and 13C NMR supported the formation of an enhanced covalent network via ester and amide linkages. Formulation optimization showed that 10% casein achieved a crosslinking degree of 93.32 ± 0.43% (p < 0.05), accompanied by rapid gelation (18 s) and a sixfold increase in storage modulus compared with the control, while gel electrophoresis profiles supported controlled degradation behavior. Resveratrol was efficiently encapsulated at 96.31 ± 1.40%, as evidenced by reduced fluorescence intensity in the cross-linked matrix, and the optimized gel retained 86% of the drug during storage. The optimized formulation exhibited enhanced antioxidant performance, with 27.03% higher DPPH radical-scavenging activity and 46.12% higher ABTS response compared to the non-crosslinked system, highlighting that structurally engineered casein-based gels can significantly enhance encapsulation efficiency and the controlled release of sensitive bioactives in pharmaceutical applications.