Effect of emulsification methods on the physicochemical properties of emulsion stabilized by calcium carbonate and sodium alginate

Abstract

Our lab’s studies have found that heavy calcium carbonate (CaCO3) with sodium alginate (SA) can synergistically stabilize Pickering emulsion. However, there were significant differences in the flow characteristics of the emulsions obtained by different preparation methods during storage. Herein, in this current work, Pickering emulsions were prepared by two-step emulsifying method (SA was added into the primary emulsion stabilized by CaCO3 for secondary shearing, M1) and one-step emulsifying method (oil phase was added to homogeneous dispersed CaCO3-SA solution for one-step shearing, M2), respectively. The particle size, microstructure, rheology and microrheological properties of these two kinds of emulsions and the interaction of CaCO3 with SA were analyzed. The results showed that the droplet size of M1 emulsion was 21.78–49.62 μm, and that of M2 emulsion was 6.50–11.87 μm. M1 emulsion had stronger viscoelasticity, and could transform into a gel state during storage. However, M2 emulsion remained in flow condition all the time which was related to the interaction between SA and CaCO3 in the aqueous phase.