Why does raw egg white change when it becomes cooked?

The change in raw egg white when it's cooked is due to a process called denaturation. Here's a breakdown:

1. The Structure of Raw Egg White

* Raw egg white is mostly water, but it also contains proteins, primarily albumin.

* These proteins are long chains of amino acids that are folded into specific 3D shapes.

* The shape of these proteins is crucial for their function.

2. Denaturation by Heat

* When heat is applied to raw egg white, the energy causes the protein molecules to vibrate.

* This vibration disrupts the weak bonds (hydrogen bonds) that hold the proteins in their specific shapes.

* The proteins unfold and become denatured.

3. The Effects of Denaturation

* Coagulation: The unfolded proteins tangle with each other, forming a network that traps water and solidifies the egg white.

* Changes in Texture: The egg white becomes firm, opaque, and rubbery.

* Loss of Function: The denatured proteins lose their ability to bind water and create foam.

4. Other Factors Affecting Denaturation

* Acidity: Acids like lemon juice can also denature egg white proteins, leading to coagulation.

* Metals: Certain metals like copper can accelerate denaturation.

In short, cooking egg white causes denaturation of the albumin proteins, which changes the shape and properties of the egg white, making it firm, opaque, and less functional.