Oil-in-water emulsions stabilized by sodium alginate microgels

In this research, sodium alginate (ALG) microgels were prepared with different ALG concentrations, and physicochemical and emulsifying profiles of these hydrophilic microgels were comparatively analyzed. Results showed that these microgels possessed different size, hardness, and surface charge. All these microgels could stabilize an oil-in-water emulsion through the Mickering mechanisms, and smaller microgels had better emulsifying capacity. The surface hydrophobicity and interfacial tension of the microgels had no exact effects on their emulsifying behaviors. Compared with the harder microgels (prepared with high ALG concentration, e. g. 4 mg/mL), the emulsifying capacities of the softer ones (prepared with low ALG concentration, e.g. 1 mg/mL) were more sensitive to the high salt concentration (200 mM NaCl) but stable under acidic environment (pH 2.0). Our research would afford a new strategy for the manufacture and application of the novel polysaccharide-based emulsifiers.