Nothing to do with emotions: Onion tears

A chemical found in onions, called as lachrymatory factor, syn-propanethial-S-oxide, is released when onion cells are damaged or cut. It is highly volatile, and once it is released from the onion cells, it mixes with the air, reaches the eyes, and triggers the nerves in the eyes. The tears are spontaneously released to protect the eyes from irritation. As a part of 'Foods and Their Specifications' course taught by Prof. Dr. Sibel Ozilgen at the Gastronomy and Culinary Arts Department, Yeditepe University students learn that in the kitchen, keeping onions in the refrigerator before cutting will decrease the energy of these volatile molecules, hence less of them will have enough energy to hit the eyes.