Question

Which enzyme is responsible for breaking down starch into simple sugars during the fermentation process in bread-making?

• A. Protease
• B. Amylase
• C. Lipase
• D. Cellulase

Hint:

Yeasts cannot directly ferment large starch molecules. Amylase acts as an essential intermediary, converting starch into fermentable maltose and glucose to feed the yeast during proofing.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
In bread-making, yeast (*Saccharomyces cerevisiae*) requires fermentable simple sugars (like maltose and glucose) to undergo fermentation.
Because wheat flour consists mostly of complex starch macromolecules rather than simple sugars, enzymes must break down these complex carbohydrates to sustain yeast activity.

Step 2: Detailed Explation:
Amylases are the starch-degrading enzymes responsible for this breakdown:
- Flour contains starch granules composed of amylose and amylopectin.
- Amylases (including endogenous enzymes in the flour and exogenous enzymes from added malt or microbial sources) hydrolyze the \(\alpha\)-(1,4) glycosidic bonds in starch.
- This enzymatic cleavage breaks starch down into dextrins, maltose, and glucose.
- The yeast then metabolizes these simple sugars to produce carbon dioxide (\(CO_2\)) and ethanol, leading to dough rising and flavor development.
Other choices:
- Protease hydrolyzes proteins (gluten) to modify dough rheology, but does not produce simple sugars.
- Lipase hydrolyzes lipids (fats) into fatty acids and glycerol.
- Cellulase breaks down cellulose, which is not the main carbohydrate substrate in wheat flour starch.

Step 3: Fil Answer:
Amylase is the enzyme that breaks down starch into simple sugars to drive yeast fermentation.
Hence, the correct option is (B).