Effect of type of fatty acid attached to chitosan on walnut oil-in-water Pickering emulsion properties.

The effect of fatty acid type bonded to chitosan on the emulsifying properties of chitosan-based particles was investigated. Capric acid, myristic acid, and stearic acid were attached to chitosan chains. Longer fatty acids in the structure of chitosan lead to the better and more uniform formation of chitosan nanogels. The contact angle of chitosan, chitosan-capric acid, chitosan-myristic acid and chitosan-stearic acid were found to be 52.5°, 60.0°, 65.1° and 72.5°, respectively. Different chitosan nanogels were used to stabilize walnut oil emulsions, and the emulsion stabilized with chitosan-stearic acid nanogels had the lowest creaming index (15.2%). Stabilized emulsions with chitosans attached to longer chain acids were more adapted to the mechanism of Pickering emulsions, in addition to having higher viscosity as well as more gel-like behavior. In general, this study showed that emulsifying properties of chitosan could be improved by increasing the number of fatty acid carbons bonded to chitosan.