Question

The cause of special flavor in onion and garlic is due to the presence of
A. Sulphur
B. Phosphorus
C. Potassium
D. Nitrogen

Answer 1

Hint:-Onion and garlic are monocotyledonous flowering plants and belong to the genus Allium. The genus Allium also includes cultivated scallion, shallot, leek, and chives.
The family is known for its use as a food flavoring and for traditional medicinal purposes. It has proved to have beneficiary cardiovascular effects and has anti-flu and anticarcinogenic properties.

Complete step-by-step solution:-
The characteristic odour and special flavor in the vegetables of allium genus is due to the presence of a chemical compound called amino acid sulfoxides. The eye watering and bad breath are also caused by this chief chemical present known as allyl methyl sulfide. The activities such as peeling and cutting of onions and garlic lead to the release of enzymes known as allinases which then converts the sulfoxides in onions or garlic into sulfenic acids. The condensation of these acids then gives rise to pungent odour. The characteristic odour is caused by the sulfur-containing chemicals.
 In garlic and onions, while chopping, peeling or cutting, the cell walls are damaged, and as a result, an enzyme is released that produces these ranges of compounds. It also acts as a defence mechanism as these chemicals act as irritants.
Thus, Option (A) is the correct option.

Note:- Among the various compounds produced by these reactions, many are unstable in nature and therefore break down further causing a chain of reactions. If the onion is ingested, these compounds are eventually broken down into allyl methyl sulfide, the same compound which is responsible for garlic breath in people consuming it.