Why do we cry when we cut onions?
When you cut an onion, cells of the onion are broken, releasing their contents. Enzymes that were kept separate now are free to mix with the sulfenic acids to produce 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 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.
Do you like onions in your food? Here are some that I like:
Other food with onions: