Onions are the edible bulb of the onion plant. There are many different species of onion plants and each produce a different type of onion with unique characteristics. Although most species are rarely eaten on their own, onions are a popular ingredient in many foods. One of their least popular attributes of onions is that many people begin to cry when chopping them. If you have ever wanted to know why onions make people cry, keep reading to find out.
Why do onions make your eyes water?
It all starts when the onion is cut. This breaks the cells of the onion and causes the enzymes to mix with amino acid sulphoxides, which produces sulfenic acids. These acids are unstable and are quickly rearranged by another enzyme to releases syn-propanethial-S-oxide. This is a volatile gas containing a combination of sulfuric acid, sulfur dioxide and hydrogen sulfide. When this gas comes in contact with our eyes we feel the stinging sensation and our body reacts by stimulating the eyes to release tears to wash the irritant away.
Ways to prevent crying when chopping onions
Water can help prevent the gas from reaching the eyes. This means that chopping an onion under running water or submerged in water may prevent crying. Freezing or cooking the onion before cooking should make the enzymes less active and reduce the chance of tears. In extreme cases eye protection can be worn.
Did you know?
Researchers in New Zealand created a tear-free onion by finding a way to prevent the action of the enzyme responsible for syn-propanethial-S-oxide production.