The Tears That Live in an Onion

I’ve started cooking recently. The only thing that is more annoying than forgetting to put salt, is the constant flow of tears while cutting an onion. So today’s question is:

Why Do Chopping Onions Make You Cry?

Turns out, the onion doesn’t want other animals to eat it (nothing new. plants do this often, check out the chilli). Chopping an onion breaks down its cells and a reaction occurs as detailed below:

• Lachrymatory-factor synthase is released into the air
• The synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid
• The unstable sulfenic acid rearranges itself into syn-propanethial-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!

Although it is very irritating, people have suggested ways to prevent it. Including this glorious invention:

From personal experience, wearing spectacles or goggles do help! Try it out the next time you cut an onion.