Why tears come while cutting a onion?

Why tears come while cutting a onion?

Onion is rich in Vitamin C and lowers cholesterol.
While chopping onions, cells inside the onion are broken and the gas that comes out forms sulfenic acid. The acid gets mixed with enzymes and forms a gas called propanethiol S-oxide. When this gas reaches our eyes, it gets mixed with water and forms sulphuric acid.
Sulphuric acid makes our eyes sting, which results in more tears and the water in our eyes produces more acid thus more irritation. Once you start cooking onions it deactivates the enzymes and slowly our eyes become normal.

The process goes as follows:

1.  Lachrymatory-factor synthase is released into the air when we chop onions.
2. The synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid.
3. The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide.
4. Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes.

The lachrymal glands in our eyes become irritated and produces tears!

How to get rid of this?

• Keep the onions in water after taking off the peel: The theory behind this is, that the gas released from onion gets absorbed by the water rather than the eyes. Many also suggest cutting onion near running water as this way water will absorb all the gas. But this is not a good method as it will lead to wastage of clean water.

• Take your tongue out while cutting onions:Taking out your tongue while cutting onions will stop your eyes from tearing. This way the gas will be absorbed by our tongue. Any kind of irritation or problem in tongue due to this has not been reported yet. So it’s safe to do so.

• Keep onion in freezer before cutting:Doing so will slow down the amount of acid that is released while cutting onions. This does not mean you need to freeze onions, you just need to keep them in the freezer for 10-15 minutes before you cut them.
  

• Wearing goggles:It’s easy to buy goggles which are tight enough so that they do not let the gas reach your eyes while cutting onions. Swimming goggles will also serve the purpose. People may make fun of you but by wearing goggles you can cut as many onions as you want without a single tear.
• Burning a candle near yourself while cutting onions can also be of great help.

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

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