Question

The bread is soft and porous when the yeast cells are mixed in the lump of wheat flour because

• A. Yeast produce benzoic acid.
• B. Evolution of $C{O}_2$makes the bread spongy.
• C. Yeast is soft and flour also becomes soft.
• D. Yeast produces acetic acid and alcohol which give softness to the bread.

Answer 1

The correct option is B Evolution of $C{O}_2$makes the bread spongy.

When yeast is added to a mixture of dough, a fermentation process begins as the yeast eats the sugars and releases carbon dioxide gas. The yeast absorbs the oxygen in the dough as it begins a reproduction of cells, dividing the single yeast cell into two cells, which then become four, and redividing continuously into increasingly larger numbers of cells. Trapped in the dough, the yeast cells produce carbon dioxide resulting in the rising of the dough until it reaches a point in size to be burst, reducing it back into its original shape to begin the rising process again. This second rising is faster due to the abundance of cells now present from multiplying continuously.