Protein-stabilized Pickering emulsions: Formation, stability, properties, and applications in foods

Background: Pickering emulsions prepared using food-grade colloidal particles can be designed to have high physical stability, tunable textural attributes, and good loading/release properties. Protein-based colloidal particles are particularly suitable for this purpose because they are widely available, inexpensive, have good emulsifying properties, and nutritional benefits. Scope and approach: This paper reviews the stabilization mechanisms of Pickering emulsions, then summarizes the preparation, properties, and applications of protein-stabilized Pickering emulsions, focusing on protein nanoparticles, microgels, and fibrils. The challenges of utilizing protein-based Pickering emulsions in the food industry are also discussed. Key findings and conclusions: At present, there are three main types of mechanisms responsible for stabilizing Pickering emulsion using proteins: (i) formation of a solid particle coating at the interface; (ii) formation of a three-dimensional viscoelastic particle network in the continuous phase; (iii) depletion stabilization. Each of these mechanisms has its own advantages and disadvantages, and selecting the most appropriate one (or combination) depends on the application requirements of the Pickering emulsion. Currently, the most common applications of protein-stabilized Pickering emulsions in the food industry are: formulation of spread-like products (like margarine); encapsulation of bioactive components; and, protection of lipids against oxidation.