Stability of glycosylated complexes loaded with Epigallocatechin 3-gallate (EGCG)

•Binding of protein to EGCG delayed the decline of antioxidant activity of EGCG.•EGCG enhance the cross-linking effect of particles in composite protein emulsion.•Glycosylated protein nanoparticles had good retention and protection to EGCG.•Release rate of EGCG in intestinal fluid was higher than that in gastric fluid. The application of Epigallocatechin-3-gallate (EGCG) in food industry was limited by its low stability in aqueous solutions and poor bioavailability in vivo. The novel EGCG glycosylated arachin nanoparticles (Ara-CMCS-EGCG) and EGCG glycosylated casein nanoparticles (Cas-CMCS-EGCG) were prepared to improve the stability and bioavailability of EGCG. The effect of different variables on the storage stability and the slow-release behavior of novel glycosylation complexes in nanoparticle background solution and artificial gastrointestinal fluid were investigated. The results showed that the DPPH scavenging activity of Ara-CMCS-EGCG and Cas-CMCS-EGCG were stable in temperature (25 ∼ 70 °C). EGCG could enhance the crosslinking effect of molecular particles in glycosylation complexes solution. The glycosylated protein nanoparticles were stable to acid-base and enzymolysis in simulated gastrointestinal fluid. The release rate of EGCG in simulated intestinal fluid was higher than that in simulated gastric fluid. The glycosylated protein carrier can not only release EGCG slowly, but also significantly improve the stability and bioavailability of EGCG in simulated gastrointestinal fluid.