Rheological behavior and microstructure of Pickering emulsions based on different concentrations of gliadin/sodium caseinate nanoparticles

The properties of Pickering emulsion stabilized by different gliadin/sodium caseinate nanoparticle (Gli/CAS NPs) concentrations were investigated through physical stability, rheological properties, and microstructure observation. The results suggested that the higher the particle concentration, the smaller the size of the emulsion. The Pickering emulsion with 4% Gli/CAS NPs displayed the smallest particle size and higher stability. All the Pickering emulsion samples showed pseudoplastic behavior which is regulated through NPs concentration and oil fractions. Frequency sweep and large deformation rheology showed that the prepared Pickering emulsions shared dominant solid characteristic which was mainly determined by the particle network in the continuous phase. CLSM and Cryo-SEM observation showed that Gli/CAS particles adsorbed on the oil-water interface and formed film structures. As Gli/CAS NPs increased, the surface film becomes denser which prevents the coalescence of adjacent oil droplets. The unadsorbed particles in the continuous phase formed a three-dimensional net structure which improved the stability and viscoelastic properties of Pickering emulsion. This work showed that the microstructure and rheological properties of Pickering emulsions could be regulated by particle concentration, which might provide interesting features for various industrial applications.