Scientists say the tongue responds to ammonium chloride
Ammonium chloride (or salmiak salt) can be found in salty licorice.

By Shivali Best for Mailonline

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WHAT IS UMAMI? Share or comment on this article: Move over, umami! Scientists have discovered a SIXTH basic taste detected by the tongue

Published: 07:08 EDT, October 6, 2023 | Updated: 07:08 EDT, October 6, 2023

Growing up, most of us learned that there were five basic tastes: sweet, salty, sour, bitter, and umami.

But it’s time to rewrite the textbooks, as scientists at the University of Southern California have discovered a new flavor.

They claim that the tongue reacts to ammonium chloride in such a way that it should be considered a sixth basic taste.

Ammonium chloride (or salmiak salt) is not widely used around the world, but it can be found in salt licorice.

“If you live in a Scandinavian country, you will be familiar with this flavor and you may like it,” said Professor Emily Liman, lead author of the study.

Growing up, most of us learned that there were five basic tastes: sweet, salty, sour, bitter, and umami. But it’s time to rewrite the textbooks, as scientists at the University of Southern California have discovered a new flavor (file image)

For decades, scientists have known that the tongue responds strongly to ammonium chloride.

However, until now, the mechanism behind this reaction is unclear.

A protein called OTOP1 is known to be responsible for detecting sour tastes, and the team wondered if ammonium chloride could also activate OTOP1.

To test this, they introduced the Otop1 gene into human cells grown in the laboratory, so that the cells produced the OTOP1 protein.

They then exposed these cells to acid or ammonium chloride, before measuring the responses.

Ammonium chloride (or salmiak salt) is not widely used around the world, but it can be found in salt licorice.

WHAT IS UMAMI?

Umami is the Japanese word for the fifth basic sense of taste, after bitter, salty, sour and sweet.

Despite being known in the East for more than 100 years, particularly in Japan, it is a relatively new concept in the West, where until 2009 only the four main tastes were recognized.

Umami means deliciousness in Japanese, but is better translated as “tasty” and provides the “meaty” flavor of meat.

It is formed from the detection of glutamates by receptors on the tongue and is the reason why monosodium glutamate (MSG) is used as a flavor enhancer.

It is also found naturally in meats, cheeses and mushrooms.

“We saw that ammonium chloride is a really potent activator of the OTOP1 channel,” Professor Liman said.

“It activates as well or better than acids.”

Further tests on mice confirmed that those with the OTOP1 gene avoided ammonium chloride, while those without it did not care about the taste.

“This was really the deciding factor,” Professor Liman added.

“This demonstrates that the OTOP1 channel is essential for the behavioral response to ammonium.”

Since ammonium chloride does not occur naturally in many foods, the researchers wondered what the advantage of trying it is.

Professor Liman suggests that the ability to taste ammonium chloride could have evolved to help us avoid consuming harmful substances that have high concentrations of ammonium.

“Ammonium is found in waste products (think fertilizers) and is somewhat toxic,” he said.

“So it makes sense that we have evolved gustatory mechanisms to detect it.”

The researchers caution that this is very early research, but they hope their findings will encourage further study.

‘Who knows? “Perhaps ammonium chloride will join the other five basic flavors to bring the official count to six,” they added.