Final answer:
Foamy egg whites appear as a fluffy and airy mass due to the unfolding and network formation of egg white proteins, primarily albumin, as they trap air bubbles while being agitated. This process is a form of protein denaturation, similar to the visible changes when egg whites cook and turn from clear to opaque.
Step-by-step explanation:
Foamy egg whites appear as a fluffy, voluminous mass that is airy and light. This is a visual manifestation of the egg whites incorporating air and becoming frothy due to agitation, such as when whipping them. During this process, the proteins within the egg whites unfold and form a network that traps air bubbles, giving the foamy texture. Foamy egg whites are utilized in culinary applications to provide structure and leavening in dishes such as soufflés and meringues.
When egg whites are whisked, the major protein it contains, albumin, denatures. Through this denaturation process, the clear, viscous egg whites turn into an opaque and frothy mass. These changes in the structure of albumin are the same as those witnessed when egg whites are cooked, such as in the case of boiled or fried eggs, where the proteins coagulate and solidify resulting in a change from clear to opaque whites.