Cow's milk contains about 3.3% total protein:

• 80% of which is made up of large casein aggregates;
• 20% of which is made up of much smaller and finely dispersed whey proteins.

The term casein (from the Latin word for cheese, caseus) refers to the primary component of milk proteins. Casein is obtained from skimmed milk, through rennet or acid precipitation.

Rennet Casein or Acid Casein is produced depending on the substance used for the precipitation.

Acid casein, whose precipitation is mainly generated through the use of hydrochloric acid (sometimes sulphuric acid), is employed by the chemical industry (to produce colours, glues, glossy paper and sealants), the food industry (as coffee whitener and cheese spreads) and in the production of pet food.

Besides being a basic ingredient in the production of any type of cheese, rennet casein, which is obtained from skimmed milk, through rennet precipitation, is employed by the food industry (in the production of cereal flakes, cheese sauces and certain meats) as well as the chemical industry (Galalite, Lanital).

(The content on this page was prepared with input from Pier Luigi Vecchia, Food Technologist)