Which is used as a preservative to protect processed food?

Options

A. Sodium sulphate
B. Saccharin
C. Sodium bicarbonate
D. Sodium metabisulphite

Answer

To determine which substance is used as a preservative to protect processed food, we need to analyze the options provided: Sodium Sulfate, Saccharin, Sodium Bicarbonate, and Sodium Metabisulfite.

### Step-by-Step Solution:

1. **Understanding Preservatives**:
- Preservatives are substances added to food to prevent spoilage caused by microorganisms and to extend shelf life.

2. **Analyzing the Options**:
- **Sodium Sulfate (Na2SO4)**:
- This compound is primarily used to dry organic liquids and in detergents. It does not serve as a food preservative.
- **Saccharin**:
- Saccharin is an artificial sweetener used to replace sugar, particularly for people with diabetes or those looking to reduce calorie intake. It is not a preservative.
- **Sodium Bicarbonate (NaHCO3)**:
- Commonly known as baking soda, it is used as an antacid to neutralize stomach acid. It does not have preservative properties.
- **Sodium Metabisulfite (Na2S2O5)**:
- This compound is a sulfur-containing preservative. It prevents oxidation and inhibits the growth of microorganisms in food, thus preserving it.

3. **Conclusion**:
- Among the options, **Sodium Metabisulfite** is the only substance that acts as a preservative to protect processed food. Therefore, the correct answer is Sodium Metabisulfite.

### Final Answer:
**Sodium Metabisulfite** is used as a preservative to protect processed food.

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