Question

Which one or more processes listed below DOES NOT produce carbon dioxide during fermentation?

• A. Brewing wine using yeast.
• B. Baking bread using yeast.
• C. Making yogurt using lactobacillus.
• D. Making cheese using fungus.

Hint:

Yeast-based fermentations (wine, beer, bread) release CO$_2$, while lactic acid bacteria and fungal fermentations mainly produce acids or flavors without CO$_2$.

Answer 1

The Correct Option is C, D

Step 1: Wine fermentation. Yeast ferments sugars $⇒$ produces ethanol and CO$_2$. Hence (A) produces CO$_2$.
Step 2: Bread fermentation. Yeast ferments sugars in dough $⇒$ CO$_2$ released, causes dough to rise. Hence (B) produces CO$_2$.
Step 3: Yogurt fermentation. Lactobacillus ferments lactose mainly to lactic acid $⇒$ no CO$_2$ produced. Hence (C) does NOT produce CO$_2$.
Step 4: Cheese fermentation. Cheese production by fungi (e.g., Penicillium) involves breakdown of proteins and fats, not CO$_2$-producing fermentation. Hence (D) does NOT produce CO$_2$.
Therefore, processes (C) and (D) do not produce CO$_2$ during fermentation.