New Flavor: Is Ammonium Chloride a Basic Flavor?

A new study shows that ammonium chloride is perceived as a basic taste on the tongue. The study reveals how taste buds perceive ammonium chloride and also exemplifies the specific taste of salt liquor popular in Scandinavia and the Netherlands. This discovery provides evidence for the existence of ammonium chloride as a basic flavor.

The Acceptance of Umami and the Discovery of Ammonium Chloride as a New Flavor

Umami was described by Kikunae Ikeda in 1908 and recognized as a separate taste in 1990. It was considered a sixth taste, joining the four basic tastes (sweet, sour, salty, bitter) recognized in the world of taste. A study conducted by researchers from the USC Dornsife College of Letters, Arts and Science found evidence for the existence of ammonium chloride as a sixth basic taste.

Research Methodology and Findings on the Discovery of Ammonium Chloride as a New Flavor

In the study, the researchers introduced the Otop1 gene into laboratory-grown human cells to test the effect of taste buds and ammonium chloride on the tongue’s sensing ability. Some cells were exposed to acid or ammonium chloride. The results showed that ammonium chloride activated the OTOP1 receptor as effectively as acid. Experiments on mice confirmed that mice with the Otop1 gene avoided ammonium chloride, while mice with the gene disabled did not.

Ammonium chloride is a compound that is a decomposition product of amino acids, which are often toxic to humans and other animals. It is thought that the ability to detect this compound taste of ammonium chloride may have evolved to help avoid harmful substances.

Researchers have observed differences between different species. The OTOP1 channels of humans and mice were strongly activated by ammonium chloride, while the OTOP1 channels of chickens were more sensitive and zebrafish were less sensitive to ammonium chloride. These differences are said to reflect the ecological niches of each organism. For example, while birds are known to be less sensitive to sour taste, they should avoid consuming ammonium chloride present in their feces.

The researchers plan to study the OTOP1 receptor’s response to ammonium chloride in more detail and learn more about its evolutionary significance. Efforts are also underway to find a more appropriate name for the receptor that could better describe the taste of food and be used in conjunction with the other five basic flavors.

This study was published in Nature Communications.