Recent Advances in Milk Protein Modification: Techniques and Functional Implications

Milk protein, a crucial natural raw material in the dairy industry, possesses multiple physiological activities. However, natural milk protein has deficiencies in key functional properties such as thermal stability, solubility, and gel characteristics, which restrict its application in dairy processing. To address this issue, modulation of the molecular structure of milk protein through protein modification technology can not only enhance its basic functionalities but also explore and impart novel functional characteristics to it. This review focuses on the precise regulation of milk protein functional properties and systematically reviews four modification technologies: 1) enzymatic modification such as hydrolysis and cross-linking; 2) physical modification such as non-thermal processing and microencapsulation; 3) chemical modification such as glycosylation, phosphorylation (dephosphorylation), and acylation (deacylation); and 4) combined modification. It discusses these technologies in terms of mechanisms, functional characteristics, and advantages and disadvantages. In light of current research progress, this article also points out that the field still faces several challenges, such as the likelihood of chemical modification causing reagent residues, the high cost of enzyme preparations, the limited effectiveness of single physical modification, and insufficient understanding of the structure-function relationship at the molecular level. Finally, it is proposed that further research should focus on developing targeted green combined modification technologies, investigating the safety and nutritional properties of modified products, and expanding the application of milk protein in high value-added special diets such as infant formula and nutritional products for the elderly, with the aim of providing a theoretical basis and technical support for promoting the high-value utilization of milk protein.