Onions – fun facts you never knew
After a serious look at onions last week, now it’s time to learn some funny details about them, some tips on using onions, and the answer as to why onions make you cry.
- Our word “onion” comes from the Latin “unio” meaning one or unity, because an onion grows as a single bulb.
- In ancient Egypt, the onion was a symbol of eternity because it is a circle‐within‐a‐circle. The Pharaoh Cheops paid workers who built the Great Pyramid in onions, garlic, and parsley and onions were painted on the walls of the pyramids. Mummies were even buried with onions.
- According to an old English Rhyme, the thickness of an onion skin can help predict the severity of the winter. Thin skins mean a mild winter is coming while thick skins indicate a rough winter ahead.
- According to the Guinness Book of World Records, the largest onion ever grown, weighed 10 pounds 14 ounces. It was grown by V. Throup of Silsden, England.
- Onions are a popular vegetable. Worldwide we grow about 50 million tons of onions a year! The average person eats about 13.7 pounds of onions a year. This really varies, for example in North America we eat about 18.6 pounds each per year, while in Libya, the average person eats 66.8 pounds of onions in a year!
- After slicing onions, wash your hands in cold water, then rub them with salt or vinegar. The salt or vinegar will remove onion smells from your hands.
- If you eat onions you can get rid of onion breath by eating parsley.
- If you need only half of an onion, use the top half. The root will stay fresh longer in the refrigerator.
- When buying onions, go for ones that feel heavy in your hand and firm.
Onions – why the tears?
It’s all about chemistry!
Onions absorb sulfur from the soil, which helps form a class of volatile organic molecules called amino acid sulfoxides; they form sulfenic acids. When you cut an onion, you break cells, releasing their contents. Enzymes that were kept separate now are free to mix with the sulfenic acids to produce propanethiol S-oxide, a volatile sulfur compound that wafts upward toward your eyes. This gas reacts with the water in your tears to form sulfuric acid. The sulfuric acid burns, stimulating your eyes to release more tears to wash the irritant away.
Cooking the onion inactivates the enzyme, so while the smell of cooked onions may be strong, it doesn’t burn your eyes. Aside from wearing safety goggles, a snorkel mask or running a fan, you can keep from crying by refrigerating your onion before cutting it (slows reactions and changes the chemistry inside the onion) or by cutting the onion under water. This can be very tricky and may lead to knife mishaps. Instead, use a sharp knife which reduces the crushing effect of slicing onions.