Advances in Pickering emulsions stabilized by protein particles: Toward particle fabrication, interaction and arrangement

With the increasing global demand for clean-label and sustainable emulsifiers that are suitable for use in agrochemicals, personal care and food industry, protein-based particles are becoming promising emulsion stabilizer in food industry owing to their considerable surface activity, biodegradability and excellent nutritional value. Accumulating evidence implies that, relative to classical rigid inorganic particles, protein colloidal particles perform more as soft particles to stabilize emulsions. A brief historical introduction to Pickering emulsions provides a conceptual framework firstly. Then, the conformational properties and methods of fabrication and modification of protein-based particles are introduced in more detail. In addition, the particle shape, interfacial arrangement and interaction are also discussed. Finally, novel application of these materials and future perspectives concerning the interfacial conformation, rheology and industrial production of protein-based Pickering particles are considered. In summary, thermal and solvent-induced aggregation are found to be the principal fabrication methods of protein-based Pickering particles. Through the complexation or covalent interaction with polysaccharides, proteins and phenolics, protein particles exhibit improved solubility, emulsification effectiveness and bioactive functionalities. According to different shapes, protein-based Pickering particles can be categorized into elongated and linear particles, spherical particles, plate-shaped particles, and fractal aggregates, which have different interfacial adsorption energy. Overall, the embedding arrangement, interfacial rheology and large-scale production of protein particles are challenges as well as opportunities that coexist in further studies.