Stabilization and microstructural network of pickering emulsion using different xanthan gum/lysozyme nanoparticle concentrations

In this paper, xanthan gum/lysozyme nanoparticles (XG/Ly NPs) were used to prepare Pickering emulsion, and the effect of particle concentration was investigated from the aspects of stability, rheology, and microstructure. Creaming index (CI) decreased along with the increase of XG/Ly NPs concentration and oil content until the particle concentration exceed 2%. At this time, the stratification disappeared, and the emulsion was more stable. Confocal laser scanning microscope showed that XG/Ly NPs form a three-dimensional network in the aqueous phase serving as a physical barrier, which can enhance the viscosity and shear resistance of the emulsion and have the maximum contribution to the emulsions' solid-like elastic properties. Increasing the particle concentration was favorable to enhancing the solid-like property and reducing the droplet size, and the stability of the emulsion was improved. Rheological analysis showed that Pickering emulsions exhibited shear-thinning behavior and good structural stability within a large strain range in a particle concentration dependent manner. The exponent n decreased from 0.70 to 0.39 as the particle concentration and oil content increased. The endeavor confirmed that microstructure and rheological performance of Pickering emulsions could be regulated by particle concentration, which might provide feasible strategy for development functional emulsion systems with controllable structures.