egg whites or ½ cup egg substitute

Egg whites, also called albumen, are the clear viscous liquid portion of chicken eggs that surrounds the yolk, constituting approximately 60% of the egg's total mass. Botanically, they consist primarily of water (approximately 90%), proteins (ovalbumin being the most abundant), minerals, and glucose, with minimal fat content. The protein structure of egg whites changes dramatically when subjected to heat or mechanical agitation, transforming from a transparent, fluid state to an opaque, gelatinous solid. This unique property makes egg whites indispensable in countless culinary applications where protein coagulation provides structure and lift.

Egg substitute refers to commercially formulated products designed to replicate egg whites' functional and nutritional properties while offering advantages such as extended shelf life, food safety guarantees, and cholesterol reduction. Common formulations include liquid pasteurized egg whites (with added gums or starches for texture), powdered egg white solids, or plant-based alternatives containing ingredients like potato starch, guar gum, and sometimes soy or pea proteins. The composition and performance characteristics vary by brand and formulation type.

Egg whites function as leavening agents, binders, and stabilizers across global cuisines. They are whipped to incorporate air, producing meringues, mousses, soufflés, and light foam desserts; used to clarify broths and stocks; employed in glazes for baked goods; and incorporated into cakes, custards, and cocktails like the classic Whiskey Sour. Egg white proteins denature and coagulate when heated, providing structural integrity to baked goods and custards. Egg substitutes replicate these functions with varying degrees of success—liquid substitutes work well in most baking and binding applications, while powdered versions require reconstitution and may require adjusted ratios depending on the desired outcome.