Zein/carboxymethyl dextrin nanoparticles stabilized pickering emulsions as delivery vehicles: Effect of interfacial composition on lipid oxidation and in vitro digestion

Abstract

In this study, zein/carboxymethyl dextrin nanoparticles (ZCPs) were used as stabilizers to prepare Pickering emulsions. The contact angle (θ) of ZCPs with a mass ratio of 2:1 (zein:CMD) was 89.1°, which was suitable for stabilizing Pickering emulsions. The droplet sizes of ZCPs stabilized Pickering emulsions were dependent on particle concentration and oil volume fraction. The droplet sizes of emulsions decreased with increasing particle concentration at a constant oil volume fraction, and increased as the oil volume fraction increased fixing particle concentration. Visual observation indicated that ZCPs stabilized Pickering emulsions at various particle concentrations and oil fractions were stable during long-term storage. The rheological measurements indicated that all emulsions exhibited shear thinning behavior and the elastic gel-like structure. Furthermore, the viscosity and gel-like structure were relied on ZCPs concentrations and oil volume fractions. Confocal laser scanning microscope showed that ZCPs formed the densely packed layer around the oil droplets. ZCPs stabilized Pickering emulsions significantly inhibited lipid oxidation compared to zein nanoparticles stabilized emulsions. In vitro digestion study suggested that the free fatty acids (FFA) released, bioaccessibility and stability of curcumin in ZCPs stabilized Pickering emulsions were higher than those in bulk oil and zein nanoparticles stabilized emulsions. These researches might facilitate the preparation of Pickering emulsions with excellent stability for nutraceutical delivery in food and pharmaceutical applications.