A characteristic feature of the Allium family is its pungency. This property originates
from the presence of sulfur-containing compounds. These precursor components such as S-alk(en)yl cysteine sulfoxide and sulfonic acid are stored in a compartmentalized form
stored in the vacuole. When the cells are ruptured, the precursor molecules react with a
cytosolic enzyme allinase, releasing a number of volatile components that include thiosulfinates,
thiosulfonates, disulfides, and sulfonic acids. Allicin, alliin, diallylsulfide, and
ajoene are volatile components present in onion and garlic products. Lachrymatory factors
(thiopropanal S-oxide, C2H5 CH SO) are generated by the action of allinase on the precursor
molecules such as allicin and alliin (Block et al., 1992). Despite their pungent nature,
Allium vegetables contain several nutraceuticals, and consumption of these vegetables, in
general, is regarded as a healthy choice