Rennin Enzyme – Function in Milk Digestion

Enzymes are the bio-catalysts produced in the body of all living organisms. They carry out a number of chemical reactions in the body. They regulate the life processes such as digestion, coagulation, respiration, growth, reproduction and development. Rennin is an important enzyme produced in the stomach of human body. It comes under aspartic group of protease enzymes. Rennin is also known as rennet or chymosin. It is very helpful for digestion milk in infants and children.

Rennin Enzyme – Function

The main function of rennin enzyme is to curdle milk. Curdling is also called as coagulation. This means milk is beaten up to separate it into semisolid curd and liquid or whey. This helps in digestion of milk proteins in the stomach. If milk is eliminated from the stomach without digestion process, the body would not benefit in any way from the milk. Curdling of milk by rennin enzyme helps the body in absorbing proteins from milk.

Curdling of milk – How does rennin help

  • Rennin is produced by the stomach in an inactive form, called prorennin.
  • After milk is consumed, the gastric acids present in stomach activates the inactive prorennin to active rennin.
  • Milk consists of four types of molecules, together called as a caseinogen enzyme. The active rennin only in presence of calcium in milk, precipitates three molecules, called alpha-s1, alpha-s2 casein and beta casein,
  • The fourth molecule is kappa casein. It doesn’t allow the precipitation of the other three molecules.
  • But the rennin enzyme makes the kappa casein molecule inactive, so that the three molecules are precipitated.
  • Milk is thus coagulated and digested properly in the stomach by rennin enzyme.

The optimum temperature that allows the coagulation of milk by rennin is 37 degree Celsius. At higher and lower temperatures, the coagulation process of milk cannot occur. Because at higher temperatures, rennin enzyme breaks down and at lower temperatures, the reaction rate is slowed down.

Where is Rennin Enzyme Produced

  • Rennin is produced in the infant immediately after the birth. As the child grows, rennin production goes down and is replaced by pepsin digestive enzyme.
  • It is produced in the inner lining of true stomach, called as abomasum in the calf that is being milk-fed by its mother.
  • The enzyme is also produced in the stomach of lamb or goat.
  • The other sources of rennin enzyme are plants, especially nettles and thistles and microorganisms such as yeasts and fungi.

Rennin Enzyme – Industrial Application

Rennin enzyme, due to its property of milk coagulation, is used in food industries. It is used in cheese production. Rennin is obtained from calf stomach as well as other non-animals sources for cheese production. For large scale production of cheese, rennin is required in large amounts. Thus, genetic engineering methods are applied for obtaining rennin enzyme in larger amounts.

3 responses to Rennin Enzyme – Function in Milk Digestion

  1. Good work, had one question for you which has really raised debates:
    what is the nutritive importance of milk to the body of adults?

  2. Does anyone have an EEI on rennin :)

  3. very good and perfect information of rennin but i want to know that rennin is found in human or not, b’coz some auther says that rennin is found in only calf and other mammles except human, some auther says rennin is doubtful in human. thanks

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