Tearless Onions

It has recently been reported that New Zealand and Japan Crop and Food research scientists are working towards using a ”gene-silencing technology to switch off the enzyme” which is the culprit for causing the eye to tear. Somehow the thought of human interfering with our food surely brings tears to my eye! It’s going to happen within the decade. The implication for me is that I’m going to work hard to ensure that I’ve a good stock of the existing onion plants and seeds and get involved with the seed bank to ensure that the traditional variety isn’t lost forever.

A short scientific explanation on how the tear causing enzyme works:

“Lachrymatory-factor synthase is released into the air when we cut an onion. The synthase enzyme converts the sulfoxides (amino acids) of the onion into sulfenic acid. The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide. Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes. The lachrymal glands become irritated and produce the tears! Oddly enough, this volatile compound is also responsible for a lot of the great taste in onions, as well as the pleasant aroma when you cook the vegetable. You'll also get sulfenic acids by cutting up garlic, chives and leeks, among other vegetables, but they don't form the same irritating gas, just a strong smell.