Question

Why bread has soft, spongy texture?

Answer 1

Bakers use two simple facts of life to create soft, spongy, moist bread:

First, they use the fact that yeast (a single-cell fungi) will eat sugar, and from the sugar create alcohol and carbon dioxide gas as waste products. The carbon dioxide gas created by yeast is what gives bread its airy texture, and the alcohol, which burns off during baking, leaves behind an important component of bread's flavor.

Second, wheat flour, if mixed with water and kneaded, becomes very elastic. The flour-and-water mixture in bread becomes stretchy like a balloon because of a protein in wheat known as gluten. Gluten gives bread dough the ability to capture the carbon dioxide produced by yeast in tiny flour balloons.

Answer 2

Answer:

Breads become spongy due to the addition of yeast in their dough. Yeast reproduces  rapidly and produces carbon dioxide gas while respiring. This gas fills the dough and  increases its volume making it to rise, thus making the bread appear spongy and fluffy.

Hope it helps you :)