Onion As A Chemical

gowritells By gowritells, 24th Apr 2015 | Follow this author | RSS Feed | Short URL http://nut.bz/2o-6-lw-/
Posted in Wikinut>Guides>Science>Biology>Human Biology

There are several reasons for tear glands of humans to get activated.But the most involuntary reason is the cutting of an onion which is discussed here.

All about the tear glands

The tear glands (lachrymal glands), located above each eyeball, continuously supply tear fluid that’s wiped across the surface of your eye each time you blink your eyelids.

They secrete tears in three forms
basal tears :lubricating agents which keep the cornea wet to keep the eye clear from dust.
reflex tears:which are secreted due to foreign particles like dust or chemical agents or vomiting,yawning etc
psychic tears:which are secreted due to emotions

Secret behind the chopping of onions

Onions produce the chemical irritant known as syn-proprietorial-S-oxide. It stimulates the eyes' lachrymal glands so they release tears.Lachrymal-factor synthase is released into the air when we cut an onion.The synthase enzyme converts the sulfoxides (amino acids) 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!
When an onion is cut, the lachrymator compounds are released causing the nerves around the eyes or lacrimal glands to become irritated. The onion's cells release these compounds into the air. When this occurs, "enzyme" works to alter the amino acids into lachrymator compounds. This form of sulfuric acid irritates the nerves around the eyes making them tear.The chemical compounds released by the onions are allyl sulfide and they also exist in garlic and spring onions.

How to avoid crying while cutting

1. Use a sharp knife to cut the onion to reduce the amount of damage to the onion cells.

2.Cool the onion in a refrigerator to suppress the scattering of the lachrymator.

3.Soak the onion in water to dissolve the amino acids. (Cutting the
onions quarters before soaking them is even more effective.)

4.Wear swimming goggles or ski goggles while cutting the onion.

5.Use a ventilator or fan to blow the allyl sulfide away.

6.Don't cut the bottom part of the onion first,it contains more chemicals.

7.Use of a chopper instead of knife to prevent the irritation to some extent.

Some more facts

The word Lacrymal is taken from Latin word "lacrima", or “tear.”

Onions are rich in two health-benefiting compounds: flavonoids and sulfur-containing compounds

Flavonoids are potential antioxidants that could protect us against cancer, heart disease, and aging. They are often found at high concentrations in the skins and outer layers of onions with yellow or brown color.

The sulfur-containing compounds are the flavor precursors that give rise to the characteristic odor and flavor of onions.

Tear-free onions have been developed by Crop & Food Research of New Zealand and House Foods Corporation of Japan in 2008.

Without enough tears the eyes feel gritty and can become red or swollen, and sometimes painful. The eyelids may stick together and the vision blur from time to time.


Acids, Chemical Reactions, Chemistry, Chopping, Lachrymal Glands, Onions, Tear Glands, Tears, Types Of Tears

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writing is my passion and I am glad when readers find my pages interesting or inspiring.

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