Outstanding antioxidant pickering high internal phase emulsions by co-assembled polyphenol-soy β-conglycinin nanoparticles

Abstract

This work reports a kind of novel antioxidant Pickering high internal phase emulsions (HIPEs; with an oil fraction, ϕ > 0.74) stabilized by soy β-conglycinin (β-CG) and polyphenol complex nanoparticles, as outstanding protective containers for lipophilic nutraceuticals. The nanoparticles with a representative polyphenol ((-)-epigallocatechin-3-gallate; EGCG) encapsulated were fabricated through an ethanol-mediated dissociation and re-assembly process of β-CG, with greater particle size and higher surface hydrophilicity observed at higher initial EGCG concentrations. Using these co-assembled nanoparticles as sole stabilizers, a kind of HIPE gels with similar gel stiffness and microstructure, could be easily fabricated at ϕ = 0.8 and a protein concentration in the aqueous phase of 1.0 wt% using polyunsatuated fatty acid-rich flaxseed oil as the dispersed phase. These HIPE gels were extraordinarily stable against heating or long-term storage, but susceptible to freeze-thawing. The as-fabricated HIPEs showed an excellent protection to β-carotene (encapsulated in oil phase) against heating, as well as an inhibition of lipid oxidation. The oxidation protection was in an EGCG concentration dependent manner. The results would be of interest for providing a novel strategy to fabricate functionalized Pickering HIPEs as potential containers or delivery systems for lipophilic nutraceuticals.