AS Biology Coursework:Investigating the effect of temperature on the rate of reaction of the essence rennet

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AS Biology Coursework 2002:

Investigating the effect of temperature on the rate of reaction of the essence rennet 

Plan

Rennet contains enzymes called chymosin, which have the property of clotting, or curding milk. Chymosins’ coagulate the protein casein found in milk, forming solid curds. 0They firstly break down specific bonds in a glycopeptides found on the surface of soluble calcium caseinate that contain casein, leaving relatively insoluble calcium paracaseinate (unstable, denuded casein particles). These particles in the presence of calcium (2-) ions coagulate to form a continuous curd.

This property of coagulating milk makes rennet a biological enzyme that is used industrially in the production of cheese, yogurt, and other diary products.

There are many forms of rennet, derived from different sources using different methods. In this investigation I will be using calf rennet, this has been derived from the inner lining of the fourth stomach of a calf. Other forms include, Maxiren (100% pure chymosine, made using rDNA technology) and rennilase (a fungal protease).

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Chymosin, known also as rennin, is a proteolytic enzyme (made up of protein), which is most stable between pH 5.5 and 6.0 hence it is stable in milk, which is at pH 5.56

Hypothesis

My hypothesis is that the chymosin enzyme in calf rennet will be most efficient at clotting milk at temperatures between 39C to 41C, which I believe to be its optimum temperature. I predict that at this temperature the calf rennet will clot the most milk. At temperatures much higher than 40C and much lower than 40C, the least amounts of milk will clot, ...

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