The fresh onion’s pungent aroma and taste can repel some people. Even more bothersome is chopping the onion, every slice bringing more tears to the eyes. Which is a crying shame because onions are layered with antioxidants, especially when eaten raw.
Sulfur is the cause of the waterworks even as sulfur compounds in the onion are responsible for its many health benefits and its odors.
Cutting into an onion breaks open the plant cells and starts a chemical chain reaction. Escaped enzymes called lachrymatory-factor synthase react with the amino acid sulfoxides (sulfur compounds) stored in the cells to form sulfenic acids.
These acids are unstable so they rearrange themselves into syn-propanethial-S-oxide, a volatile sulfur gas that wafts up to the eyes and causes a stinging sensation. The lacrimal (tear) glands produce reflex tears to wash away the irritant.
How can you stop the drama? Wear goggles while chopping the onion to shield your eyes from the tear gas. If you’d rather not look silly in the kitchen, freeze the onion for 15 minutes before chopping. The cold inhibits the enzymes and slows the chemical reactions. Also, start with a sharp knife to minimize damage to the onion cells in the first place.
You can also choose the variety of onions. Regular onions are grown in sulfur-rich soil, which is how they get so pungent. Sweet onions such as the Vidalia variety are grown in low-sulfur soil, so they are milder in taste and cause fewer tears.
photos: in order - depositphotos/ehaurylik; robynmac; claudiodivizia; vladvitek; jeep5d