Preparation of Pickering Flaxseed Oil-in-Water Emulsion Stabilized by Chitosan-Myristic Acid Nanogels and Investigation of Its Oxidative Stability in Presence of Clove Essential Oil as Antioxidant

The aim of this study was to obtain a stable flaxseed oil (FSO)-in-water Pickering emulsion (PE) stabilized by chitosan (CS)-myristic acid (MA) nanogels and to investigate the oxidative stability of the CS-MA nanogels-encapsulated FSO in the presence of clove essential oil (CEO) in shell or core modes. First, MA was successfully conjugated to CS by amide linkages in different MA-to-CS ratios to improve the emulsifier property of CS. Subsequently, the effects of pH, MA-to-CS ratio, and oil-to-nanogel ratio on the stability and droplet size of PE were examined. The most stable PE was obtained at pH 8, MA-to-CS ratio of 0.75:1, and oil-to-nanogel ratio of 10:1. Finally, the oxidative stability of the emulsions was analyzed. The results indicated that the formation of the CEO shell around dispersed droplet surfaces of FSO was more efficient in reduction of lipid oxidation and droplet size than admixing CEO in the oil core. The best oxidative stability was observed in the PE with 0.1% CEO shell. Overall, this work showed that by engineering the interfacial architecture via the combination of steric hindrance of CS-MA nanogel-based membrane and the interfacial load of CEO, appropriate physical and oxidative stabilities of the emulsions were obtainable.