Pickering and high internal phase Pickering emulsions stabilized by protein-based particles: A review of synthesis, application and prospective

Food proteins can be readily converted into particles and used to produce food grade Pickering emulsions, including normal Pickering emulsions (PEs) and high internal phase Pickering emulsions (HIPPEs). Plant and animal proteins and their complexes with polysaccharide and polyphenols are commonly used as Pickering particles. The ability of protein-based Pickering particles to stabilize PEs and HIPPEs depends on interaction between proteins and the complexed compounds. Protein and protein-based Pickering particles have shown to possess the ability to stabilize the HIPPEs which have internal phase ratio higher than 74%. Although the protein-based Pickering particles are used to stabilize both PEs and HIPPEs, there are significant differences in mechanism through which they are formed and stabilized. Although there are notable advances in linking-particle properties, migration and spreading of protein particles at the oil-water interface, reduction in interfacial tension with stability of PEs and HIPPEs; these aspects still need continued research. Pickering particles produced using proteins and their complexes are greatly affected by processing conditions and other compounds present in food. This aspect appears to be less rigorously researched, despite the substantial effect of processing parameters on the stability of PEs and HIPPEs. This review compiles and assesses the latest advances on production, characterization, application and stability of PEs and HIPPEs stabilized by protein and protein-based Pickering particles.