Gel-like pea protein Pickering emulsions at pH 3.0 as a potential intestine-targeted and sustained-release delivery system for β-carotene

In recent years, there is increasing interest in the development of food-grade Pickering emulsions as promising delivery systems for bioactive compounds. Our previous work reported that most of the proteins in pea protein isolate (PPI) at pH 3.0, present in the nanoparticle form, can effectively perform as a kind of food-grade Pickering stabilizers for oil-in-water emulsions (LWT, 2014). The purpose of this study was to further report that PPI-stabilized emulsions at pH 3.0 exhibited great potential to act as intestine-targeted and sustained-release delivery systems for beta-carotene. The emulsions were produced by microfluidization at a specific protein concentration of 6.0% (w/v) and varying oil fractions (phi) of 0.2-0.6. The results indicated that increasing phi was favorable for the gel-like network strengthening of these emulsions. The gel formation was largely related to the droplet flocculation as well as inter-floc attractive interactions. The in vitro simulated digestion results showed that the release of beta-carotene during the intestinal digestion of these emulsions could be well modulated by altering phi. The gel-like emulsion at phi = 0.6 exhibited much lower release of beta-carotene, but higher stability towards degradation during the digestion, than that at phi = 0.3. The findings provide important information not only for the design of novel delivery systems for lipophilic bioactive components, but also for the development of plant protein-based formulations. (C) 2015 Elsevier Ltd. All rights reserved.