Forms of Casein Protein

Casein is one of the two main proteins in milk. The other is whey. This milk protein is generally classified as either acid casein or rennet casein. It is used to fortify foods like fabricated cheeses, bread and cereal. It's also used to increase the consistency in foods like pudding or soup. You'll also find milk proteins in nutrition bars and high-protein supplements.

Rennet Casein

To produce rennet casein, skim milk gets treated with an enzyme that makes the casein coagulate. When it coagulates, it separates from the other components in the milk. The protein concentration of this form of casein is 80 to 95 percent.

Acid Casein

When acid casein is produced, skim milk gets exposed to an acid treatment. This triggers a reaction that causes the casein protein to separate from the milk's other components. This type of casein is generally identified by the acid used to produce it, such as hydrochloric acid casein, lactic acid casein or sulfuric acid casein. The protein concentration of this form of casein also is 80 to 95 percent.

Caseinate

Caseinate is derived from acid casein in which the acid is neutralized with an alkali. Sodium caseinate and calcium caseinate are common forms. Other forms include ammonium caseinate and potassium caseinate. All of the casseinates have protein concentrations of about 90 percent. In addition to providing protein, caseinates serve as whipping aids, water binders and emulsifiers. You will see them in diet foods, coffee whiteners, whipped topping, processed meats and egg substitutes.

Milk Protein Concentrate

Milk protein concentrate, or MPC, contains both casein and whey. The protein content is variable, from 42 percent to more than 90 percent. This form of casein protein is commonly referred to using the percentage protein it contains. For example, if it has a protein concentration of 60 percent it is called MPC 60. This protein concentrate comes in dry powdered and liquid forms. The liquid for of MPC also is called ultrafiltered milk. If you use high-protein nutritional supplements, energy bars or sports drinks marketed for the health-conscious, athletes or the elderly you are likely to find milk protein concentrate or ultrafiltered milk on the ingredient list.