Utilization of β-lactoglobulin- (- )-Epigallocatechin- 3-gallate(EGCG) composite colloidal nanoparticles as stabilizers for lutein pickering emulsion

摘要

Controlling and manipulating thickness, packing, charge and chemical composition of the interfacial layer is highly relevant to the fabrication of stable emulsion delivery systems. In this work, composite nanoparticles with antioxidant capacity were prepared using beta-lactoglobulin nanoparticles (beta-lgNPs) and (-)-Epigallocatechin-3-gallate (EGCG) and applied as Pickering emulsifiers to stabilize a model lutein emulsion. The primary interactions between beta-lgNPs and EGCG were found to be hydrogen bonding and hydrophobic effects through Fourier transform infrared spectra. beta-lactoglobulin-EGCG composite nanoparticles (beta-lgENPs) exhibited much stronger antioxidant activity than beta-lgNPs, especially for beta-lg-EGCG at a molar ratio of 15:1. Adsorbed protein fraction (F-ads), saturation surface load (Gamma(sat)), adsorbed layer thickness as well as dynamic interfacial tension were determined to compare the interfacial adsorption properties of native beta-lg, beta-lg-EGCG complexes, beta-lgNPs and beta-lgENPs. The binding of EGCG had almost no influence on the physical stability of either native beta-lg or beta-lgNPs stabilized emulsions. The least degradation of lutein occurred in the emulsion stabilized by beta-lgENPs, in which 87.2% of lutein was still retained in emulsion after 30 days of storage, confirming the enhanced protection by the formation of beta-lgENPs. Potential mechanisms were proposed to explain the difference between beta-lg-EGCG complexes and beta-lgENPs in stabilizing lutein emulsions.