Question

Which preservatives are usually used for preservation of wine?
(A). Bisulfites
(B). Citric acid
(C). Diethyl pyrocarbonate
(D). Sorbic acid
Choose the correct answer from the options given below:

• (B) and (C) only
• (B) and (D) only
• (A) and (C) only
• (B) only

Hint:

Sulfites (bisulfites) are the universal antioxidant and antimicrobial agents added to almost all commercial wines.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Wine preservation requires chemical agents capable of protecting the product from both oxidative degradation and microbial spoilage by yeasts or acetic acid bacteria.

Step 2: Detailed Explanation:
- Bisulfites (sulfur dioxide, SO$_2$) (A) are the most widely used preservatives in winemaking. They act as antioxidants to prevent browning and as antimicrobials to inhibit unwanted wild yeasts and bacteria.
- Diethyl pyrocarbonate (DEPC) (C) (and its modern successor, dimethyl dicarbonate or DMDC) is used as a cold sterilant in wines to prevent refermentation after bottling by killing active yeast cells.
- Citric acid is an acidulant, not a primary preservative, and sorbic acid is used less frequently and typically only in sweet wines in combination with sulfur dioxide.
Therefore, (A) and (C) are the primary chemical preservatives associated with wine.

Step 3: Final Answer:
The preservatives traditionally used for wine are bisulfites and diethyl pyrocarbonate, representing Option C.