No tear onion chopping

[iqarus]

As onions are sliced or eaten, cells are broken, allowing enzymes called alliinases to break down amino acid sulphoxides and generate sulphenic acids. A specific sulfenic acid, 1-propenesulfenic acid, formed when onions are cut, is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase or LFS, giving syn-propanethial-S-oxide, a volatile gas known as the onion lachrymatory factor or LF.[20] The LF gas diffuses through the air and eventually reaches the eye, where it activates sensory neurons, creating a stinging sensation. Tear glands produce tears to dilute and flush out the irritant.[21] Chemicals that exhibit such an effect on the eyes are known as lachrymatory agents.
Supplying ample water to the reaction while peeling onions prevents the gas from reaching the eyes. Eye irritation can, therefore, be avoided by cutting onions under running water or submerged in a basin of water.[21] Rinsing the onion and leaving it wet while chopping may also be effective. Another way to reduce irritation is by chilling, or by not cutting off the root of the onion (or by doing it last), as the root of the onion has a higher concentration of enzymes.[22] Using a sharp blade to chop onions will limit the cell damage and the release of enzymes that drive the irritation response. Chilling or freezing onions prevents the enzymes from activating, limiting the amount of gas generated. Eye irritation may be avoided by having a fan blow the gas away from the eyes as the onion is being cut.
It is also possible to avoid eye irritation by wearing goggles or any eye protection that creates a seal around the eye. Contact lens wearers can experience less immediate irritation as a result of the slight protection afforded by the lenses themselves. It may also be that lens wearers are familiar with controlling the more reflexive actions of their eyes with regards to irritation; as this is an ability they require when manipulating the lenses to prevent blinking.
The amount of sulfenic acids and LF released, and the irritation effect, differs among Allium species. On January 31, 2008, the New Zealand Crop and Food institute created a strain of "no tears" onions by using gene-silencing biotechnology to prevent synthesis by the onions of the lachyrmatory factor synthase enzyme.

some of the posted replies have scientific grounds, it mostly comes down to the enzyme reaching the eye.

[Mrs Ronnie H]

Mate! its breathing through your nose that causes the tears.



Minno

Thats right-- it is your breathing that causes you to cry when chopping onions.
Also it is the root part on the onion that holds the odour. Try slicing your onion without cutting the root part off it until last.

ORRRRRRRRRRRRRRRRRR-- you could always try a clothes peg on your nose. ????

Ronnie

[Noelm]

ooorrrrr, get someone else to do it! how easy is that?

[STUIE63]

I always just wore safety glasses they worked perfectly just looked a bit silly wearing them in the kitchen
Stuie

[Sandman]

Let them rest in chilled water for awhile jobs done , If dont want to do that get someone else to cut them up he he the apprentice

[Trio181]

Hey there
I am a chef and have been cutting onions for 24 yrs!!
The only way to stop the sting is to keep the onion fumes out of sinuses!!
By this i mean try like hell not to breath through your nose (MOUTH ONLY!!) it works but as soon as you even sniff once ya crying!!
Good luck

[dec0guy]

I always cut up unions under the rangehood in the kitch with fan set to max. Sucks away the union fumes and no tears!