Coagulation is the process by which proteins change from a liquid or semi-liquid state to a solid or semi-solid state, often as a result of heat, acid, or enzymatic action. This process is essential in various cooking techniques and plays a crucial role in determining the texture and consistency of food.
For example, when eggs are cooked, the heat causes the proteins in the egg whites and yolks to coagulate, transforming them from a fluid state to a firm, opaque mass. This is the basis for dishes like scrambled eggs, omelets, and custards.
In dairy, coagulation is integral to cheese-making, where the addition of rennet, an enzyme, causes the proteins in milk to coagulate, forming curds that are then processed into cheese.
Coagulation also occurs when preparing tofu, where soy milk is curdled using a coagulant like calcium sulfate or magnesium chloride, resulting in the formation of tofu blocks.
The extent of coagulation affects the final texture of these foods, with gentle coagulation yielding a softer texture and more intense coagulation producing a firmer result.