Preparation and characterization of high internal phase Pickering emulsions stabilized by hordein-chitosan composite nanoparticles

In this study, hordein and chitosan were used to prepare composite nanoparticles (H-Cs) by anti-solvent pre-cipitation method at pH 4.0. The addition of chitosan caused the increase in zeta-potential of H-Cs and the gradual decline in fluorescence intensity of H-Cs, indicating that chitosan was located on the hordein surface during the formation of H-Cs. Fourier transform infrared spectra of H-Cs illustrated that hordein and chitosan were combined to form composite nanoparticles by hydrogen bonds and hydrophobic interactions. The com-posite nanoparticle H-C25 (the mass ratio of hordein to chitosan 25:1) was chosen as Pickering stabilizer by measurement of three-phase contact angle. The O/W (oil-in-water) high internal phase Pickering emulsions (HIPPEs) stabilized by H-C25 (2.0 %, w/v) with oil fractions of 75 %-85 % were further prepared. The confocal laser scanning microscope images and the rheological results indicated these HIPPEs had strengthen gel-like structure, leading to their excellent self-supporting capacity and storage stability. This study provides inspiration for designing protein-based food-grade HIPPEs in substitutes of partially hydrogenated vegetable oils (PHOs).

Automated summary

In this study, composite nanoparticles (H-Cs) were prepared using hordein and chitosan through the anti-solvent precipitation method at pH 4.0. The addition of chitosan increased the zeta-potential of H-Cs and resulted in a gradual decrease in fluorescence intensity, indicating that chitosan was located on the hordein surface during H-Cs formation. Fourier transform infrared spectra confirmed the formation of composite nanoparticles through hydrogen bonds and hydrophobic interactions. The H-C25 (hordein to chitosan mass ratio of 25:1) composite nanoparticle was chosen as a Pickering stabilizer and successfully stabilized high internal phase Pickering emulsions (HIPPEs) with excellent self-supporting capacity and storage stability. This study provides inspiration for the development of protein-based food-grade HIPPEs as substitutes for partially hydrogenated vegetable oils (PHOs).