Impact of Chitosan-Capric Acid Nanogels Incorporating Thyme Essential Oil on Stability of Pomegranate Seed Oil-in-Water Pickering Emulsion

The aim of this study was to obtain a stable Pomegranate Seed Oil (PSO)-in-water Pickering emulsion stabilized by chitosan (CS)-capric acid (CA) nanogels incorporating Thyme Essential Oil (TEO). Firstly, CS-CA nanogels were synthesized at different ratios of CA to CS (0.25:1, 0.5:1, and 0.75:1). Scanning electron microscopy images showed that by increasing the CA to CS ratio, the uniformity of particles was increased. In the following, CS-CA nanogels were used to stabilize PSO-in-water emulsions. The findings revealed that the most stable emulsion was obtained at pH 8, CA-to-CS ratio of 0.5:1, and an oil-to-nanogel ratio of 10:1. In addition, the interfacial structure of emulsion droplets indicated that the CS-CA nanogels contributed to the stability of emulsion through both the formation of an interface layer and a network on the surface of dispersed droplets. Finally, the oxidative stability and microstructure of the emulsions stabilized by CS-CA nanogels incorporating TEO (0.1%) were evaluated. The results showed that TEO increased the oxidative stability of the emulsion and reduced the emulsion droplet size.