Tearless Onions: Japanese Scientists Have Developed A Less Pungent Variety That Also Won’t Cause Foul Breath

Japanese scientists have succeeded in creating onions that aren’t pungent. These onions will not make you cry and won’t leave you with “onion breath.”

Japanese food manufacturing company House Foods Group has announced the development of a new tearless variety of onion that’s less pungent. This directly translates to no odors on your hands from handling them or foul breath after eating them.

The team has been perfecting their tearless onion for over 10 years. Apparently, scientists had assumed for many years that the chemical Propanethial-s-oxide was responsible for the tears, explained Scicurious, a postdoc in biomedical research.

“Scientists knew that an enzyme called alliinase breaks down the chemical PRENCSO to pyruvic acid. They thought that it just spontaneously went from there to the tear-jerking Propanethial-s-oxide.”

Interestingly, garlic also contains alliinase. But this equally strong condiment doesn’t make people cry when they cut it. Hence, the Japanese team suspected something else was at play, continued Scicurious.

“They added alliinase specifically to PRENCSO… and got NO Propanethial-s-oxide. So the alliinase alone is not responsible for the breakdown. There’s another, missing enzyme.”

Detailed analysis revealed that the culprit is lachrymatory factor (LF) synthase, a powerful enzyme found in onions but not their milder garlic cousins. The team won the 2013 Ig Nobel for Chemistry for their discovery. They claim they can now disable the enzyme while retaining the flavor of the onion.

The team figured out how to neutralize the onion’s odor by halting the production of this enzyme, which is released when the onion is cut. The team managed to do so by zapping it with irradiating ions. By disabling the reactive properties of this enzyme, the scientists have successfully retarded a chemical reaction that both causes tears and produces thiosulfinate — a substance responsible for the onion’s signature strong smell.

Unfortunately, these odorless onions may be vulnerable to insects or animals which were earlier repelled by the offensive smell profile, explained Eric Block.

“They are often compounds that will repel insects or animals that try to bite into it. So everything is, I believe, very Darwinian from the standpoint of the chemistry of plants, a very large number of compounds that we view as either being pleasant smelling or unpleasant smelling.

“They’re not there for our pleasure. They’re there to allow the plant to survive in a very hardscrabble world, a world where there are lots of worms in the ground and animals that would devour something that exists as a bulb and has to survive in the ground. So if you’re living in the ground as a perennial, as the garlic does, you need to defend yourself, and you can’t run. Plants can’t run. So they stay and fight, and they’re wonderful at it.”

The Japanese team is to yet announce if they want to bring their odorless and tearless onions in the market.

[Image Credit | Shutterstock via Beatnikhiway]