Casein is a mixture of many proteins found in the mammalian milk. It is largely used in the food industry to manufacture cheese, yogurts and other products from milk and it has a high value on the market.
Casein is the name of component present of some protein. This mixture is very nutritive due to bring many aminoacids and also calcium and phosphorus.
Formula and structure: Casein has not a defined chemical formula, however the average molecular mass is 2000 g mol-1 and there are at least 21 types of different casein molecules:
|Molecular weight (kDa)||23.6||25.7||24||19|
|Number of Aminoacids||199||207||209||169|
The molecule of casein has a size between 80 to 1000 nm dependent on the type of the casein that forms the mixture and these molecules usually are grouped in a micelles of 20-25 casein molecules.
Occurrence: Casein can be found in the milk from every mammal on nature. These proteins are biosynthesized by glands present on the female bodies.
Preparation: The casein is a mixture of complex macromolecules, thus it cannot be easily prepared by synthetic chemical methods. The casein is extracted from the cow milk and its production depends on the lactation stage of the cows.
Physical properties: Ethylene Casein is a yellow to tan powder and its melting point is 280 ºC and above this temperature it decomposes. It is slightly soluble in water, so that it could form a cloudy suspension in water. It is hygroscopic and incompatible with oxidizing agents.
Chemical properties: Casein is not so soluble in water due to the structure has a high content of apolar aminoacids, thus casein has around 40% of proline, leucine and isoleucine residues. The large number of casein types is due to the lack of disulfur bonds, which does not allow the formation of a defined tertiary structure. α and β caseins are immunoglobulin structures and for that reason, casein is largely used in the study of hormonal disorders, especially in patients insulin-dependents.
Uses: Casein is largely used in food industry and processes, especially to produce cheeses from different type of milks: cows, goats or sheep. Moreover, casein is used to manufacture glues and coats and also plastic and fibers. Additionally, casein is a component of many biochemical assays, especially the assays related to insulin. Recently, casein has been used as a protein supplement.
Health effects / safety hazards: Casein is not dangerous to health. It is combustible and can react with some oxidizing agents.