Casein is a group of related phosphoproteins found in mammalian milk, making up approximately 80% of the proteins in cow's milk. These proteins are characterized by their ability to form stable micelles in the presence of calcium ions, which is crucial for milk's colloidal stability. Casein is widely used in the food industry, particularly in cheese production where it coagulates to form curds. It serves as a slow-digesting protein source in nutritional supplements. Chemically, caseins are rich in proline and contain phosphorylated serine residues that bind minerals. They have applications in pharmaceuticals, cosmetics, and as emulsifiers. Research shows potential health benefits from casein-derived peptides, including antihypertensive and antimicrobial effects. Due to its amphiphilic nature, it exhibits excellent surface-active properties.