How many times you have cried in your whole life???? ..... Once .....Twice.....Thrice .....and how many times you have cried during chopping an onion???? ...... all the time .....is this your answer ????.... Probably Yes .We mostly deluge our tears during the assassination of this eatable beast. But Have you ever wondered why do onions bring tears to our eyes when we cut them? Get ready to know why...

Onions contain amino acid sulfoxides that form sulfenic acids in the onion cells. Both the enzymes and the sulfenic acids are kept separately in the cells. When you cut the onion, the otherwise separate enzymes start mixing and produce propanethiol S-oxide, which is a volatile sulphur compound that starts wafting towards your eyes. The gas that is emitted reacts with the water of your eyes and forms sulphuric acid. The sulphuric acid thus produced causes burning sensation in your eyes and this in turn leads to the tear glands secreting tears. Thus you end up with watery eyes every time you cut onions at home. It is the sulphur compound in the onions that also leave a typical odour of onions on your hands and utensils even after washing.

Cooking the onion inactivates the enzyme, so while the smell of cooked onions may be strong, it doesn't burn your eyes.