Sulfur dioxide is employed to bleach wood pulp in paper manufacture. It is also added as an additive in the making of jam and marmalade, usually in the form of sulfite compounds. If its amount exceeds $10\ \text{mg kg}^{-1}$, it has to be declared as an ingredient in the jam. What is the reason for adding sulfur dioxide to jam?
- AIt is a bleaching agent and removes the undesirable colours from the fruit used in the jam.
- BIt is a preservative that destroys unwanted bacteria and enzymes.
- CIt is a reducing agent and removes the acids that give the jam a sharp taste.
- DIt is an acidic gas and maintains the pH of the jam at a suitable value to give it a sharp taste.