Characterization of pickering emulsion stabilized by colloidal sodium caseinate nanoparticles prepared using complexation and antisolvent method

Abstract

The aim of this study was to investigate the effect of different treatments on sodium caseinate (SC) colloidal suspension physicochemical properties and their ability to act as a Pickering stabilizer for reduced-fat formulations. Heat-treated SC (HSC) particles were prepared by adding glucose (HSC-Glc) and tannic acid (HSC-TA), followed by precipitation with ethanol (EtOH) and ethyl cellulose (EC) dissolved in ethanol (EC/EtOH). Stable colloidal suspensions were prepared by adjusting SC, Glc, TA, and EC to 10, 4, 2, and 5 mg/mL respectively, and using a 5: 3 solvent/antisolvent (mL/mL). The stable Pickering emulsions (PEs) in the volumetric ratio of 50: 50 (mL/mL) oil: water were prepared using HSC/EtOH, HSC-Glc/EtOH, and HSC-Glc-TA-EC/EtOH particles as the aqueous phases. They showed higher contact angles and lower interfacial tensions in comparison with native SC and long-term physical stability. Heating and the addition of anti-solvent played the main role in stabilizing PEs with SC and the addition of Glc, TA or EC has only an auxiliary role that could be added or removed depending on its application purpose in the food or pharmaceutical industry. They especially had a major role in the oxidative and thermal stability of the emulsion.