The tongue has a sixth basic taste: ammonium chloride.

In the early 1900s, scientists identified four basic tastes. language: salty, sweet, bitter, sour. Then, in the late 1980s, Japanese Kikunae Ikeda first proposed umami as a core flavor.

Umami comes from Japanese and means “delicious” and is due to the presence of glutamate and other amino acids in some foods, especially those rich in protein. Umami does not have a strong flavor, but rather a subtle and lingering flavor that stimulates salivation and enhances the flavor of other ingredients. Some foods that contain umami are Parmesan cheese, dry-cured ham, ripe tomatoes, soy sauce, anchovies, shiitake mushrooms, and fish stock.

Sixth basic taste

In a study published Oct. 5 in Natural communicationsUSC Dornsife neuroscientist Emily Lyman and her team discovered that the tongue responds to ammonium chloride through the same protein receptor that signals sour taste, thus becoming the sixth basic taste.

“If you live in a Scandinavian country, you will be familiar with this taste and may like it,” says Liman, a professor of biological sciences. In some northern European countries, salted licorice has been a popular candy since at least the early 20th century. The candy contains salmiac salt or ammonium chloride.

In recent years, they identified the protein OTOP1, which detects sour taste. They suggested that this protein might also respond to ammonium chloride due to its effect on acid levels in cells.

To test this, they introduced the Otop1 gene into lab-grown human cells and then exposed some of them to acid or ammonium chloride. The results showed that ammonium chloride activated the OTOP1 receptor as effectively as acid.

Additional tests in mice confirmed that those with the OTOP1 gene avoid ammonium chloride, and those without it do not care about the taste.

Lyman suggests that the ability to taste ammonium chloride may have evolved to help organisms avoid harmful substances.

“Ammonia is somewhat toxic,” he explained, “so it makes sense that we have evolved taste mechanisms to detect it.”

The team also found that sensitivity to ammonium chloride varies among species, possibly due to differences in the environment.