Question

______ is used as a bleaching agent for wheat flours.

• A. CO2
• B. Benzoyl peroxide
• C. Potassium metabisulphite
• D. Sodium benzoate

Hint:

Benzoyl peroxide acts purely as a bleaching agent and does not modify the physical properties or baking performance of the gluten network, unlike multi-functiol agents like chlorine gas.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Freshly milled wheat flour possesses a pale yellow hue caused by carotenoid pigments (principally lutein).
Flour bleaching agents are food additives used to oxidize and decolorize these pigments, producing a white flour preferred for many baking applications.

Step 2: Detailed Explation:
Carotenoids contain conjugated double bonds that absorb light in the blue-violet region, giving the flour its yellow tint.
Benzoyl peroxide is an organic peroxide that acts as a powerful bleaching agent.
When added to flour, it slowly decomposes over 24 to 48 hours to yield free radicals that oxidize the double bonds of carotenoids, converting them into colorless compounds.
This results in a clean, white flour.
In contrast:
- Carbon dioxide (\(CO_2\)) is an inert gas used in modified atmosphere packaging or aeration, not bleaching.
- Potassium metabisulphite is a reducing agent (antioxidant and preservative) that inhibits browning, but does not bleach flour pigments.
- Sodium benzoate is a common antimicrobial food preservative.

Step 3: Fil Answer:
Benzoyl peroxide is the primary additive used specifically as a bleaching agent for wheat flour.
Hence, the correct option is (B).