Question

What are the chemical principles behind the fermentation process in making bread?

Answer 1

The fermentation process in bread-making is a biochemical reaction driven by yeast, typically Saccharomyces cerevisiae, which converts sugars into carbon dioxide (CO₂) and ethanol under anaerobic conditions. Initially, yeast breaks down glucose through glycolysis, producing pyruvate, ATP (energy), and NADH. In the next step, alcoholic fermentation, pyruvate is converted into ethanol and CO₂. The CO₂ forms bubbles that get trapped in the elastic gluten network, a protein structure developed during dough kneading, causing the dough to rise and create its light, airy texture. Enzymes like invertase and amylase facilitate the breakdown of complex carbohydrates into fermentable sugars, while byproducts such as organic acids and alcohols contribute to the bread’s flavor and aroma. During baking, the heat kills the yeast, stops fermentation, and solidifies the dough’s structure while allowing the CO₂ to expand further, resulting in the bread’s final volume and texture. This intricate process is essential for both the physical properties and taste of bread.