Fabrication and characterization of pickering emulsions stabilized by octenyl succinic anhydride -modified gliadin nanoparticle

Abstract The oil-in-water (O/W) Pickering emulsions stabilized by octenyl succinic anhydride (OSA) modified gliadin nanoparticles (OGNPs), which were prepared through a facile anti-solvent precipitation procedure and ultrasound treatment using gliadin powders, then modified by OSA, have been successfully fabricated. FT-IR result confirmed that the gliadin nanoparticles were modified by OSA. The mean size and three-phase contact angle of OGNPs were larger than those of gliadin nanoparticles, and the zeta potential reversed from positive to negative while the surface and shape of gliadin nanoparticles were destroyed. The effects of OGNPs concentration, OSA content and environment factors viz, pH and ionic strength on the properties of emulsions were investigated. The images, optical microscopy, confocal laser scanning microscopy (CLSM), and droplet size measurement of Pickering emulsions were evaluated. An increase in OGNPs concentration led to a formation of smaller droplets, which increased emulsification efficiency. Similar results were obtained with the addition of OSA from 2% to 10%. Stable emulsions could be developed at the low pH value due to high electrostatic repulsion. Increasing the NaCl concentration destabilized the Pickering emulsions. CLSM showed that OGNPs could be absorbed at the oil-water interface and form a densely packed layer on the surface of spherical oil droplets, which exhibited good stability for 14 days storage. These results suggested that OGNPs may be a promising stabilizer of Pickering emulsions, which may be used as delivery carriers of bioactives.