Recent advances of protein modification strategies to enhance the freezing stability of food emulsions: Principles, applications, and prospects

Emulsion-based foods typically employ proteins as their stabilizers, and their quality maintenance mostly relies on freezing conditions. Currently, improving the freezing stability of food emulsions through various strategies has been a topical issue in food science fields, and the modification targeting proteins is an essential research direction. This review discusses the destabilization mechanisms of food emulsions during freezing, including changes in the aqueous and oil phases, lipid oxidation, changes in pH and ionic strength, and denaturation or inactivation of proteins as emulsifiers. Then, it illustrates the role of the spatial structural properties of proteins and the formation of interfacial protein films in maintaining the freezing stability of emulsions. Moreover, this review highlights the effects of protein modification strategies on the freezing stability of emulsions and emulsion gels, including enzymatic hydrolysis treatment, glycosylation, salt and pH treatment, polyphenol addition, and physical treatment. It also discusses the further application of protein-modified Pickering emulsions in the food industry. In summary, modification treatments performed on proteins are effective in improving the freezing stability of food emulsions, and this area still has considerable room for exploration in the future, such as treatments involving emerging technologies or emerging substances and the synergistic effect of different treatments in maintaining emulsion freezing stability. This review will provide valuable theoretical insights into the production of high-quality and shelf-stable emulsion-based food products.