Enhancing the storage and gastrointestinal passage viability of probiotic powder (Lactobacillus Plantarum) through encapsulation with pickering high internal phase emulsions stabilized with WPI-EGCG covalent conjugate nanoparticles

In this study, we demonstrated the role of Pickering high internal phase emulsions (HIPEs) stabilized with the whey protein isolate (WPI)/(-)-epigallocatechin-3-gallate (EGCG) covalent conjugates on the storage and GIT passage viability of probiotics powder (Lactobacillus Plantarum). At pH 9 value, the WPI-EGCG covalent conjugates by free-radical induction reaction formed hydroxyquinone or hydroxyquinone dimers with better wettability, and digestive enzyme inhibition effect and smaller particle size. Then, the WPI-EGCG covalent conjugates were used to stabilize the O/W type Pickering emulsion. The oil fraction (ϕ) addition led to an increase in the droplet size and modulus of Pickering emulsions toward to generate gel-like structure. On the other hand, at a constant ϕ value, the droplet size of these Pickering HIPEs reduced with increasing particle concentration (c) from 0.5% to 5%, indicating that high c can stabilize more oil droplets. Encapsulation of Lactobacillus Plantarum powder with the Pickering HIPEs was successful to enhance the viable cell count after 14 days storage and GIT digestion. The protective effect of Pickering emulsions was improved with the addition of the c and/or ϕ value. Therefore, Pickering HIPEs can be applied as a promising carrier for enhancing the viability of probiotic powder during storage and GIT digestion by reason of the high oil phase fraction and the adsorption of the WPI-EGCG covalent conjugates on the droplet interface.