The Science Behind Why Onions Make You Cry
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Understanding the Tear-Inducing Onion
Onions can be handled without causing tears, but the moment you slice, chop, or crush them, your eyes might start to water. This reaction is actually a protective mechanism for the onion, designed to deter animals from consuming it while it was growing underground.
The structure of an onion bulb consists of numerous rectangular cells, each containing vacuoles. These vacuoles are membrane-bound compartments filled with a specific enzyme known as lachrymatory factor synthase (LF), which acts as an irritant.
When an onion is cut, the vacuoles rupture, releasing LF. This enzyme then interacts with the contents of the onion cells, which include sulfenic acid, leading to a chemical reaction. This reaction produces a gas called syn-propanethial-S-oxide, which disperses into the air and can irritate the eyes. The eyes respond to this gas by producing tears to eliminate the irritant, explaining why we cry when cutting onions.
Interestingly, the intensity of this reaction varies among different onion types. Red, white, and yellow onions contain higher levels of LF, while green onions, scallions, and sweet onions have lower amounts, which is why not all onions trigger tears.
How to Cut Onions Without Crying
If you want to avoid tearing up while chopping onions, there are a few effective strategies. One method is to cut onions in a well-ventilated area or use a fan to blow the irritating gas away from your face. Alternatively, refrigerating the onion before cutting can slow down the movement of molecules, making the chemical compounds less volatile.
Fun Facts About Onions
According to the National Onion Association, the average American consumes about 20 pounds of onions annually, leading to approximately 450 semi-truck loads of onions being consumed each day in the United States.
Libya holds the record for the highest per capita onion consumption, with individuals in the country eating an average of 66.8 pounds each year.
In 2014, Tony Glover from Leicestershire, England, grew the largest onion on record, weighing in at 18 lbs 11 oz and measuring 32 inches at its widest point.
Texas has designated the 1015 sweet onion as its state vegetable. Developed by a horticultural professor at Texas A&M in the 1980s, it is named for its ideal planting date of October 15 and is exclusively cultivated in the Rio Grande Valley of South Texas.
Georgia's state vegetable is the Vidalia onion, which is only cultivated in a specific region of southern Georgia.
In 2016, China was the leading producer of onions, yielding 20.5 million metric tons, followed by India with 13.4 million metric tons, and the United States at 3.3 million metric tons.
Explore More
For those interested in more intriguing facts, check out "The Wonderful World of Completely Random Facts" series on Medium. You can also discover even more interesting information in the four volumes of "Knowledge Stew: The Guide to the Most Interesting Facts in the World."
The first video titled "Why Do Onions Make Me Cry?" provides an engaging exploration of the biological processes behind this common kitchen experience.
In the second video, "WHY DO ONIONS MAKE YOU CRY? And how to prevent it?", viewers can learn effective techniques to minimize tears while chopping onions.