National Occupational Competency Testing Institute (NOCTI) Culinary Practice Exam

Which ingredient primarily contributes to the leavening of angel food cakes?

1. Sugar

2. Flour

3. Yeast

4. Egg whites

The correct answer is: Egg whites

Egg whites are the primary ingredient that contributes to the leavening of angel food cakes. When whipped, egg whites create a stable foam that traps air. This aeration is crucial for the texture and rise of the cake, as the air bubbles expand during baking, resulting in a light and airy structure. The proteins in the egg whites also provide stability to the foam, allowing it to hold its shape and support the cake as it rises. In contrast, sugar, while important for flavor and moisture, does not play a direct role in the leavening process. Flour contributes to the structure of the cake but is not responsible for leavening; it provides the necessary starches and proteins for the cake's overall integrity. Yeast is a leavening agent found in many baked goods, but it is not used in angel food cakes, which rely on the whipped egg whites instead.