Question

The puffed-up appearance of the dough is due to fermentation by yeast. Identify the gas liberated during this process:-
A. Methane
B. Carbon dioxide
C. Hydrogen sulfide
D. Ammonia

Answer 1

Hint:Fermentation is a combination of catabolic and metabolic activities that produce different chemical changes in the substrate. In other words, it is also known as the production of energy from carbohydrates in the absence of oxygen.

Complete answer:
1.Fermentation is divided into three stages primary, secondary, and conditioning.
2. We need to ferment the dough for the formation of bread from it and in other bakery products.
3. Firstly the preferment is added to the dough for the fermentation in the dough. This will take a long time period of 8 to 10 hrs.
4. In this process different chemical reactions take place in which Simple sugar or carbohydrates present in the dough is converted into ethanol and carbon dioxide.
Carbohydrates = ethanol + carbon dioxide
5. The carbon dioxide is lighter in weight than the other gases so it has a tendency to rise up. After fermentation, the amount of carbon dioxide is increased in the dough, and tries to come out of it. So it makes the dough puffy and raises the level of dough also.
6. In most of the products the dough rises twice this is due to the carbon dioxide which is released during the anaerobic breakdown of carbohydrates into alcohol and carbon dioxide in the presence of yeast.

Hence during the process of fermentation the gas liberated is CARBON DIOXIDE.

Note: 1:- when the yeast starts the process of fermentation in the dough it gives rise to the tiny bubbles of carbon dioxide within the dough.
2:- As carbon dioxide is a light-weighted gas, so due to its lightweight it starts moving upward and results in the puffed appearance of the dough.
3:- carbon dioxide plays an important role in bakery products. Only due to this carbon dioxide the bakery products become soft and spongy.