- Scientists claim that the tongue reacts to ammonium chloride
- Ammonium chloride – or ammonia salt – is found in salted licorice
Growing up, most of us learned that there are five basic tastes – sweet, salty, sour, bitter and umami.
But it’s time to rewrite the textbooks, because 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 is a sixth basic taste.
Ammonium chloride – or ammonia salt – is not commonly used worldwide, but can be found in salted licorice.
“If you live in a Scandinavian country, you are familiar with this taste and may like it,” said Professor Emily Liman, lead author of the study.
Growing up, most of us learned that there are five basic tastes – sweet, salty, sour, bitter and umami. But it’s time to rewrite the textbooks because scientists at the University of Southern California have discovered a new flavor (stock image)
Scientists have known for decades that the tongue reacts strongly to ammonium chloride.
However, the mechanism behind this reaction remains unclear.
A protein called OTOP1 is known to be responsible for detecting sour tastes, and the team wondered whether ammonium chloride might also trigger OTOP1.
To test this, they introduced the Otop1 gene into human cells grown in the lab so that these cells produced the OTOP1 protein.
They then exposed these cells to acid or ammonium chloride before measuring the reactions.
Ammonium chloride – or ammonia salt – is not commonly used worldwide, but 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.
Although it has been known in the East, particularly in Japan, for more than 100 years, it is a relatively new concept in the West, where only the four main flavors were known until 2009.
Umami means deliciousness in Japanese, but is best translated as “taste” and gives the meat its “meaty” taste.
It is formed from glutamates recognized by receptors on the tongue and is the reason monosodium glutamate (MSG) is used as a flavor enhancer.
It also occurs naturally in meat, cheese and mushrooms.
“We saw that ammonium chloride is a really powerful activator of the OTOP1 channel,” said Professor Liman.
“It activates as well or better than acids.”
Further testing on mice confirmed that those with the OTOP1 gene avoided ammonium chloride, while those without this gene did not mind the taste.
“That was really the deciding factor,” Professor Liman added.
“It shows that the OTOP1 channel is essential for the behavioral response to ammonium.”
Given that ammonium chloride does not occur naturally in many foods, the researchers questioned what benefit there would be in trying it.
Professor Liman suggests that the ability to taste ammonium chloride may have evolved to help us avoid consuming harmful substances with high concentrations of ammonium.
“Ammonium is found in waste products – think fertilizers – and is somewhat toxic,” she said.
“So it makes sense that we evolved taste mechanisms to detect it.”
The researchers note that this is very early research, but hope that their results will stimulate further studies.
‘Who knows? “Perhaps ammonium chloride will join the other five basic flavors, bringing the official number to six,” they added.