Beyond particle stabilization of emulsions and foams: Proteins in liquid-liquid and liquid-gas interfaces

In the early 20th century, Pickering and Ramsden revealed that solid particles could be utilized as emulsion stabilizers. Later, it was shown that particles can be used to aid in stablilization of foam as well. Differentiated from the emulsions/foams constructed by using surfactant agents, particle-stabilization offers significant advantages, such as better interfacial stability, non-toxicity, and less sensitive to environmental influences. Therefore, particle-stabilized foam and emulsion systems have the potential to gain more applications in the food, drug delivery, and cosmetic field. The internal mechanism and principle of particle stabilization interface have been clarified by introducing the classic mechanism of Pickering stabilization. By summarizing the additional/different effects of the protein, the relationship between the adaptive behavior of the protein in the interface and the protein structure has been explained. Furthermore, the functions of protein besides interface stabilization are introduced, such as encapsulation, taste masking and the catalytic properties of Pickering particles. Finally, deep thinking was triggered based on the existing research foundation, a new concept of "edible capillary foam" was proposed, and a new outlook was made. It is anticipated that the perception acquired from the current intense activity in this field will help researchers to reform existing materials and invent additional formulations, facilitating the exploration of additional engineering applications.