Onion stands out as the third largest fresh vegetable industry in the US. Onions, cut, sautéed, fried and in many other forms, find their place in almost every meal. But cutting these delicious vegetables is often a tearful experience.
Of course, these tears are not caused by any emotion. These are described as reflex tears from irritants. You can read the rest of our article to find out why onions make you “cry” and how to avoid the effects of this popular vegetable.
The natural environment of underground onions is full of creatures like field mice that like to gnaw at the roots. Onions have developed a special defense mechanism against this gnawing.
Onions release various enzymes and sulfenic acid when their “skin” is opened. These compounds combine to produce the irritating gas, propanethial S-oxide. Propanethial S-oxide, as a tearing agent, causes tears when it comes into contact with the eye. Propanethial S-oxide turns into sulfuric acid when it comes into contact with the layer of water that covers and protects your eyeballs.
However, like onions, our eyes also have their own defense mechanisms. When the nerves in the eye detect a tearing factor, they produce tears and try to remove this factor from the eye.
Of course, as you probably know, different types of onions have different effects and some are less teary than others. The types of onions that create the harshest chemical reactions are those that contain a lot of sulfur compounds. These include yellow, red and white onions. Sweeter varieties, such as scallions, usually have less sulfur, so they have less tear-creating effects.
In addition, plant scientists have also produced onions that do not cause tears, by genetic transformations. Although these onions are not yet grown on large scales, they are available in some specialty markets.
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