why do we tear when we cut onion?
Answers
Explanation:
Onions produce the chemical irritant known as syn-propanethial-S-oxide. It stimulates the eyes’ lachrymal glands so they release tears. Scientists used to blame the enzyme allinase for the instability of substances in a cut onion. Recent studies from Japan, however, proved that lachrymatory-factor synthase, (a previously undiscovered enzyme) is the culprit (Imani et al, 2002).
Maule’s seed catalogue for 1891 by Wm. Henry Maule (Firm). Henry G. Gilbert Nursery and Seed Trade Catalog Collection (on the Internet Archive), National Agricultural Library.
The process goes as follows:
Lachrymatory-factor synthase is released into the air when we cut an onion.
The synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid.
The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide.
Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes. The lachrymal glands become irritated and produces the tears!
yellow onions popular in cooking are the biggest culprits, and sweet, mild Vidalia onions are the least likely to trigger tears. Luckily, onions are the only type of vegetable that cause this crying reaction, because of their unique sulfur .......