Which substance is known to stabilize eggs in a recipe?

The correct choice is an acid, as acids play a crucial role in stabilizing eggs in various recipes. When egg whites are whipped, they form a foam structure that incorporates air; the addition of an acid, such as cream of tartar or lemon juice, helps to maintain the stability of this foam. The acid lowers the pH, which strengthens the protein structure of the egg whites, making them less likely to collapse.

Furthermore, the presence of an acid can enhance the volume and texture of whipped egg whites, resulting in lighter and fluffier outcomes in recipes like meringues or soufflés. This stabilization is particularly important in culinary applications relying on the aeration properties of eggs. While other ingredients like sugar and salt can have their own effects on eggs or a recipe, an acid is specifically recognized for its capability to effectively stabilize whipped egg whites.