Rennin, applications

Although acid caseins are employed for a number of purposes, rennet caseins in which the protein remains associated with calcium and phosphate are preferred for plastics applications. Rennet is the dried extract of rennin, obtained from the inner lining of the fourth stomach of calves, and is a very powerful coagulant. As little as 0.2 parts per million are said to be sufficient to coagulate slightly acidic milk. Its coagulating power is destroyed at 100°C. 

Source. Enzymes for food applications come from all three kingdoms plant, animal, and microbial. Traditionally used plant and animal enzymes are the plant proteases such as papain, ficin and bromelain, plant amylases from malt, and animal rennin which is used in cheese manufacture. Microbial cells are the usual and most promising future source of industrial enzymes. Estimates of the number of microorganisms in the world tested as potential sources of enzymes fall around 2% with only about 25 organisms, including a dozen or so fungi, currently used for industrial enzymes. 

The application of fermentation processes in the production of foodstuffs continues to be a field of constant growth and economic value. For example, the development of a bacterial strain that produces rennin, a compound that is used as a coagulant and ripening agent in the production of cheese, is reported to represent a potential cost reduction in cheese manufacturing in the United States of at least 500,000 annually. 

Proteases have found practical application in various food and other technologies for instance, rennin is used in the dairy industry for the manufacture of hard cheeses, while plant proteases, such as papain, are employed in the prevention of protein hazes in beer. 

---