POP - Denaturing and Coagulating a Protein Microlesson

Denaturing and Coagulating a Protein

Heat causes the protein to denature; the higher the temperature the faster proteins denature and then coagulate.  

Quick Glance: Extra Whip Please!

Have you ever eaten egg whites or had a latte or cappuccino with foam on top? 

If you said yes then you have consumed a protein that has been denatured. Denaturing a protein is when heat or an acid is applied to a protein in order to change the structure. This happens often in cooking. Coagulation is a form of denaturing a product or changing the structure. When milk thickens or cheese is formed, then coagulation has taken place. This process helps to improve the texture and taste of animal-based products.

Explore: A Little Chemistry Lesson

Science Daily defines protein denaturation as

the alteration of a protein shape through some form of external stress (for example, by applying heat, acid or alkali), in such a way that it will no longer be able to carry out its cellular function.

Warning- a little chemistry ahead!! Natural proteins are shaped like coils or springs. When natural proteins are exposed to heat, salt, or acid, they denature—that is, their coils unwind. So, proteins change their structure. A good example is when you cook a protein like egg whites. They go from liquid to solid. This is not always reversible but sometimes it is!

 

 

 

But Why...

Why do we want to denature proteins? Many times, if we change the chemical structure of a protein, it will make it easier to digest and even more tender. It also changes the taste. Denaturing a protein by heat will cook the meat and make it tasty and safe to eat. Using acids can help tenderize meat and make it absorb liquid. This is often used in marinades.

The video below will take you through the denaturation and coagulation process.

  

Wait...This Is A Lot Of Chemistry

Now that you understand that proteins can be structurally changed we will discuss another concept, coagulation. Coagulation is defined as the change in the structure of the protein (from a liquid form to solid or a thicker liquid) brought about by heat, mechanical action, or acids. Oftentimes, this term is used to describe the process of cooking egg white or making cheese. Coagulation causes the protein to clot, hence the egg whites become thick. This can even happen when heat is applied to milk. It will curdle or form a thin layer on the top or a foam layer. You cannot reverse this process. You can however over denature or coagulate which can cause the texture to become tough and damage the taste. Basically, overcooking or processing.

Check out this video on how cheese is made.

 

Challenge

So do you think you understand proteins? Try the challenge below to test your knowledge.

 

Takeaway: Which Comes First?

Milk or tea first? Cream or coffee first? This is a funny question.  

But for true coffee and tea lovers, they argue about which should come first. Food science can explain which is best. When milk is heated above a certain temperature, the taste, and texture change. So, if someone is to pour cream or milk into a hot cup of coffee, it could rise quickly and change the taste. But, if the milk is already in the bottom of the cup or poured first, it warms slowly as the tea or coffee is being poured in. Check out this short video to explain this theory.

 

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