Egg White Foam
The physical stress of beating egg white can create a foam. There are two types of physical stress caused by beating them with a whisk, the first being that the whisk drags the liquid through itself, creating a force that unfolds the protein molecules. This process is called denaturation. The second stress comes from the mixing of air into the whites, which causes the proteins to come out of their natural state. These denatured proteins gather together where the air and water meet and create multiple bonds with the other unraveled proteins, and thus become a foam, holding the incorporated air in place. This is because the proteins consist of amino acids; some are hydrophilic (attracted to water) and some are hydrophobic (repelled by water). This process is called coagulation.
When beating egg whites, they are classified in three stages according to the peaks they form when the beater is lifted: soft, firm, and stiff peaks. Overbeaten eggs take on a dry appearance, and will eventually collapse. Egg whites will not beat up correctly if they are exposed to any form of fat, such as cooking oils or the fats contained in egg yolk.
Read more about this topic: Egg White
Famous quotes containing the words egg, white and/or foam:
“Thy head is as full of quarrels as an egg is full of meat.”
—William Shakespeare (1564–1616)
“Their errors have been weighed and found to have been dust in the balance; if their sins were as scarlet, they are now white as snow: they have been washed in the blood of the mediator and the redeemer, Time.”
—Percy Bysshe Shelley (1792–1822)
“Yet ere I can say where—the chariot hath
Passed over them—nor other trace I find
But as of foam after the ocean’s wrath”
—Percy Bysshe Shelley (1792–1822)