Strategy of two birds with one stone: epigallocatechin-gallate assisted structuring of egg yolk granules multiphase gels for controlled release of blueberry anthocyanins.

Blueberry anthocyanins (BA) are naturally antioxidants that are unstable in digestion. Enhancing their effective release in intestine is a current focus. In this study, a previously developed controllable mixed gel of egg yolk granules (EYGs) and salted ovalbumin was combined with EGCG co-pigment to further improve the digestive stability of BA. Results indicate that EGCG-induced hydrogen bond enhancement and hydrophobic shielding tightened protein conformations while regulating aggregation of denatured proteins during gelation. The changes also induced enhanced thermal stability, increased elasticity and chewiness, and a more porous microstructure. In vitro digestion demonstrated that the gel matrix and EGCG significantly enhanced BA stability in the stomach, enabling gradual release during intestinal. Besides, SPOE-EB21 exhibited the greatest BA release during intestinal digestion, exceeding the release from SPOE-BA by 6.35-fold. The development of mixed gels of EYGs, salted egg white, and EGCG provides a new strategy for creating highly stable natural pigment foods.