Hydrogels from quinoa protein aggregates: structural features, functional properties, and delivery application

Quinoa protein aggregates (QPs) were obtained through acid-heat treatment and explored as carriers for resveratrol (Res). The treatment increased the particle size and surface charge stability of quinoa protein (QP), promoted the exposure of hydrophobic groups, and enhanced β-sheet content. The aggregates provided effective physical junctions, enabling the formation of a continuous and interconnected curdlan-based hydrogel network. Compared with QP gel, QPs gels showed higher water-holding capacity, improved freeze-thaw stability, and greater Res encapsulation efficiency. Res was retained in a non-crystalline state within the protein gel, with improved stability under light exposure, heating, pH changes, and ionic stress. Fluorescence quenching results indicated that hydrophobic interactions and hydrogen bonding were the main forces involved in QPs-Res complex formation. In vitro digestion demonstrated controlled Res release throughout simulated gastrointestinal digestion, together with improved bioaccessibility. Overall, QPs provide a promising plant-based gel platform for the encapsulation and gastrointestinal delivery of hydrophobic bioactive compounds.