Scientists Discover New Taste Beyond the 5 We Know

There are five recognized tastes we can detect, but scientists think they’ve discovered a mechanism by which we can detect a sixth.

Taste-bud receptors on the tongue. Nemes Laszlo/Shutterstock

We all know the five basic tastes that our tongues can detect: sweet, salty, sour, bitter, and umami (the savory taste of monosodium glutamate, or MSG). However, new research has found that there’s a sixth basic taste that we’re capable of perceiving.

It’s Found in Salt Licorice

The study, published in early October in Nature Communications, found that the tongue can respond to ammonium chloride through the same protein receptor that signals a sour taste, according to neuroscientist Emily Liman and her team.

“If you live in a Scandinavian country, you will be familiar with and may like this taste,” Ms. Liman said in a statement.

According to the statement, salt licorice has been a popular candy in some northern European countries, at least since the early 20th century. The candy includes salmiak salt, also called ammonium chloride, among its ingredients.

However, this isn’t to say that the taste itself is newly discovered; what Ms. Liman and her team have identified is what they believe is the part of the tongue that detects this flavor. It’s called the OTOP1 protein receptor, a receptor also linked to our ability to taste sour things.

Ability May Have Developed to Avoid Poisoning

To identify this, researchers introduced the gene for OTOP1 into lab-grown human cells and then exposed some to acid or ammonium chloride. Their results showed that ammonium chloride can activate the OTOP1 receptor as well as acid can. They confirmed this using mice with and without the gene for this receptor. Those with it avoided ammonium chloride, and those without it didn’t notice the taste.

However, ammonium chloride isn’t found naturally in many foods, and researchers question the advantage of being able to taste it.

“Ammonium is somewhat toxic,” Ms. Liman pointed out. So it makes sense that people developed taste mechanisms to detect it.

Ms. Liman and the team emphasized that this is early research and that they hope these findings encourage further studies.

Going forward, researchers plan to extend their studies to understand whether sensitivity to ammonium is conserved among other members of the OTOP proton family of receptors expressed in other parts of the body, such as the digestive tract.