Protein - Coagulation, Foam Formulation, Gluten Formation, Denaturation

Protein Coagulation

Proteins can undergo a process known as coagulation, where they change from a liquid to a solid state.
This takes place when the protein is exposed to heat, causing the protein structure to change and become more rigid.
When eggs are cooked, the heat causes the protein in the whites and yolks to coagulate, changing them from a liquid to a solid state. Firmness of the egg depends on the cooking time.

Eggs can also be used to form foams in food preparation, which are important in dishes like meringues and soufflés.
When egg whites are beaten, the protein in the egg whites unwinds and creates a network that traps air bubbles, forming a stable foam.
Sugar is often added to the egg whites to stabilise the foam and prevent it from collapsing.

Gluten is a protein found in wheat, barley, and rye. When water is added to these flours and the mixture is kneaded, the gluten proteins link together to form a network that gives the dough structure and elasticity.
Gluten is what allows dough to rise during baking. The network created traps the gases produced by yeast, causing the dough to expand.
The amount of kneading and the type of flour used can affect the amount of gluten formation.

Protein denaturation is a process where the proteins lose their shape due to the breaking of chemical bonds. This can occur due to exposure to heat, motion (like whipping), or acid.
Denatured proteins can bond together in new ways, causing a change in the texture of the food. For example, beating egg whites causes the proteins to denature and form a foam.
The process of denaturation and coagulation is crucial in many cooking processes, like coagulation of egg proteins when making an omelette.