The egg white is made up of 88% water. Among the other constituents, we can find proteins with the ovoalbumin, renowned for its properties as coagulant and surfactant (it enables to stabilize the foam of the beaten egg whites). The two other main proteins of the white are the lysosyme and the ovotransferrin.
Shaking the egg whites quickly makes air enter the water of the white, which forms a finer and finer emulsion as they are beaten. The proteins, which are present in the white, trap the air within the water, thus forming some foam. When the whites are firm, they can be slowly mixed with the preparation we wish to make lighter. So egg whites are essential to lots of pastry recipes (mousses, meringues, creams, cakes, ice-creams and sorbets), but also to cooked meats and hot or cold dishes requiring to expand and reduce physically.
COAGULATING / GELLING / BINDING
When the egg white and egg yolk are warmed up, we can see that the liquid becomes solid. The egg is said to be coagulated or cooked. The egg proteins (yolk and white) are at the origin of this coagulation. This is a precious reaction to give consistency to some recipes (pasta, surimi, sweets, cooked meats…). Gelling, elasticity, texture, firmness are a few of their culinary features that the egg white allows to modulate.
The whiteness of this ingredient occurs in numerous recipes for the whitening of some dishes. It is also widely used to thicken and fix the other food colourings.
The egg white allows, regarding candies for instance, to avoid the sugar crystallization (succose). This is an essential point for the perfecting of some caramels, nougats and candies which have to remain smooth despite the important presence of sugar.
The lysozyme of the white has a sweet taste 200 times more intense than the one of the sweetening thaumatin protein.
Added to the wine as soon as the must starts to ferment, the lysozyme of the white egg allows to avoid the growth of bacteria responsible for the involuntary stopping of the fermentations, of the slow fermentations, of the increase in volatile acids. It allows a complete stopping or a control of the malolactic fermentation and a stabilization after the malolactic fermentation.
It was used in the past for the gold-leaf cladding, the albumin of the white beinga protein glue. Nowadays, it is particularly used in oenology to soften the red tannic wines.