Why do the eyes water when cutting the Onion?

Why does this happen when the eyes water when cutting the onion?

You go to chop an onion while cooking or to fry an egg, and tears start to well up in your eyes because of the grated onion! What a matter of trouble! But what is the relationship between cutting the onion and watering the eyes? Why does this happen? The question does not come to mind?

Onions contain a variety of sulfur-containing compounds, one of which is amino acid sulfoxide. When the onion is cut, the enzyme called allinase inside its cells is released, which turns amino acid sulfoxides compounds into volatile sulfenic acid (sulfenic acid); Which, on contact with the tears, produces a compound called syn-propanethial-S-oxide, which is responsible for the watery eyes. Simply put, mild sulfuric acid is produced on contact with the tears, so it irritates the eyes.

It should be noted here that the sensation of burning is detected by the brain through the free nerve ending above the cornea (where many nerves come together), then this feeling is carried by the ciliary nerve to the parasympathetic nerves to the lacrimal gland. (lacrimal gland)-stimulates. The result is watery eyes.

What is the way to escape now?

If you keep this onion in the fridge or soak it in water before chopping, then you will not burn your eyes while chopping the onion and as a result your eyes will not water. Isn’t that fun? Try it..

This is because sulfonic acid loses its effectiveness when it comes into contact with water when soaked in water. The same happens with refrigeration. Then the effectiveness of sulphonic acid decreases due to cold. As a result, it cannot form syn-propanethial-S-oxide compounds on contact with eye water. Due to this, it does not irritate the eyes.

Frequently Asked Question (FAQs):

  • Why does this happen when the eyes water when cutting the onion?
  • What is the way to escape now?

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