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In flour, glutenin and gliadin are the key proteins. When water is added, they merge into gluten, giving dough its elasticity. Kneading strengthens these bonds, and heat in the oven causes gluten to set, forming the scaffold that holds the loaf together.
Leaveners such as yeast, baking soda, and baking powder create the airy structure we love. Baking soda reacts with acidic components to emit CO₂, while baking powder releases CO₂ twice—once upon hydration and again at baking temperatures. Yeast ferments starches, producing sugars, alcohol, and CO₂ that lift the dough.
At high temperatures, proteins and sugars rearrange, forming complex, ring‑shaped molecules that brown the crust. These Maillard products deliver toasted, savory aromas and deepen flavor, creating the sensory experience that distinguishes fresh bread.
Caramelization begins around 356 °F (180 °C). Heat breaks down sugars, releasing water that steams, and triggers the formation of flavor compounds such as diacetyl (butterscotch), esters and lactones (rum‑like), furan (nutty), and maltol (toasty).
