Scientists in Japan have discovered that it might be possible to produce a tear-free onion without compromising on the taste.

It had previously been thought that the tear-inducing effect that occurs when an onion is sliced was linked to the onion’s flavour compounds.

However, scientists from Japan’s House Foods, reporting in today’s [Thursday’s] issue of the British journal Nature, have reported that a compound called propanthial S-oxide is responsible for the tear effect. The compound is produced by the appropriately named enzyme, lachrymatory-factor synthase, which is not responsible for the onion’s flavour or nutritional value.

The fact that the tear-inducing enzyme appears not to be linked to the onion’s flavour means that it is theoretically possible to engineer an onion that tastes the same but does not make people cry when they chop them.

A non-lachrymatory onion would be one of the few GM products engineered for purely consumer benefits rather than for agricultural benefits.