MCQ Detailed View

The strong and distinctive odour of garlic is due to the presence of sulphur-containing compounds. When garlic is intact, it contains a compound called alliin, which is odorless. However, when garlic is cut, crushed, or chewed, an enzyme called alliinase is activated. This enzyme converts alliin into allicin, a sulphur compound responsible for the sharp and pungent smell we immediately associate with fresh garlic.

Allicin is highly unstable and easily breaks down into other sulphur compounds such as diallyl disulfide, allyl methyl sulfide, and ajoene. These compounds continue to give garlic its long-lasting odour, even after cooking. Some of these byproducts are also responsible for the lingering garlic smell on breath after eating raw or cooked garlic.

Sulphur compounds are unique because they can create strong odors even in very small amounts. This is why garlic’s smell is so noticeable and difficult to mask. It is also the reason garlic is sometimes used in chemical studies as a reference for volatile sulphur chemistry.

In addition to giving garlic its smell, these sulphur compounds provide important health benefits. Allicin and related molecules have been studied for their antibacterial, antifungal, and antioxidant properties. Garlic has traditionally been used in medicine for boosting the immune system, lowering blood pressure, and supporting heart health.

Other options in the question are incorrect. Fluorine compounds and chlorine compounds do not occur naturally in garlic and are not responsible for its odour. The correct answer is sulphur compounds, especially allicin, which plays the key role in producing garlic’s characteristic smell.

Thus, the distinct odour of garlic is a result of sulphur chemistry, making this a fascinating example of how chemical compounds influence everyday life through both senses and health.