Whey is a low calorie milk serum remaining after casein removal in cheese manufacturing. Composition and properties of whey depend on the type of cheese production process, type and the quality of the used milk. Whey mostly consists of lactose, proteins, vitamins, minerals, enzymes, hormones and growth factors. Functional and nutritional roles of whey components meet the requirements for dietary food.
Whey proteins are liquid fractions of 20% milk proteins, which remain in whey after casein removal. The increase in the temperature of milk processing leads to denaturation of proteins and a decrease in their content. The most common whey proteins are albumin and globulin. Separation and fractionation of whey proteins may be carried out as precipitation, combined with acid treatment, high temperature treatment or centrifugation (centry-whey process), and as a membrane process (usually ultra- or microfiltration followed by a diafiltration and spray drying). Whey proteins can also be separated based on their molecular mass, charge and hydrophobicity.
It is a well-known fact that whey proteins possess admirable nutritional and functional components, such as essential amino acids, bioactive peptides, antioxidants and immunopotentiators.  Research   of bioactive compounds and nutrients pushed whey protein to the forefront of the functional food sector, therefore, the implementation of these proteins in the diet and supplements has the potential to address many metabolic imbalance-caused diseases, and it seems imperative to harness their potential.