What is the primary function of yeast in baking?

The primary function of yeast in baking is to make bread rise. Yeast is a living organism that ferments sugars present in the dough, producing carbon dioxide gas and alcohol as byproducts. The carbon dioxide gas gets trapped in the dough's structure, causing it to expand and rise. This process not only creates a light and airy texture in the final product but also contributes to the development of flavor during fermentation. The growth and activity of the yeast are crucial to leavening bread; without it, the dough would remain dense and flat.

While yeast does impart some flavor and aroma during fermentation, its main role focuses on the leavening process, making it essential for creating the desired texture in baked goods. The other options, such as adding color or sweetening the dough, are not primary functions of yeast in baking.