What is another ingredient that can increase the volume of whipped egg whites?

Citric acid is an effective ingredient for increasing the volume of whipped egg whites. It works by stabilizing the proteins in the egg whites, which helps to create a more robust foam structure. When egg whites are whipped, the proteins unfold and create a network that traps air, resulting in the volume increase. Citric acid lowers the pH of the egg whites, which promotes better foaming and creates a more stable meringue or whipped egg white mixture. This is particularly beneficial when making recipes that rely on airy textures, such as soufflés or meringue-based desserts.

Other ingredients listed do not provide the same stabilizing effect. Flour can weigh down the mixture when added, gelatin, while it can stabilize other mixtures, does not contribute to volume in whipped egg whites, and cocoa powder, being dense and heavy, can also detract from the lightness and volume of the whipped egg whites.