Licorice lovers rejoice: Scientists hint at a new basic taste

Sweet, salty, bitter, sour, and umami are the five tastes we perceive. These sensations are detected by taste buds distributed all over the tongue. Recently, scientists have discovered something intriguing: we may perceive a sixth taste, particularly familiar to licorice candy enthusiasts.

Licorice candies spark such intense feelings that people either love them or deeply dislike them. They are extremely popular in Scandinavia, where you can find them in every store. Although they look very appetizing, their flavor can be polarizing. Licorice is initially salty and tart, then it even becomes spicy. This unique taste profile is thanks to ammonium chloride, a salt responsible for the licorice flavor. According to scientists, ammonium chloride might deserve recognition as a basic taste.

Initially, we recognized only four basic tastes: sweet, sour, salty, and bitter. Then came umami, discovered by Kikunae Ikeda, a professor at the University of Tokyo. In 1908, he isolated glutamic acid from kombu seaweed. We can easily recognize this taste when eating Parmesan cheese, dishes with soy sauce, or fish sauce. Asians are masters at recognizing the umami taste.

Europeans and Americans had more difficulty with it, so umami was formally recognized as a basic taste only in 2000. Scientists from the University of Miami discovered specific receptors on the human tongue that detect glutamic acid.

For many years, it has been known that we can detect the taste of ammonium chloride and respond to it. What if there are specific receptors on the tongue responsible for detecting it? This is the question Emily Liman from USC Dornsife College of Letters, Arts, and Sciences asked herself. The initial findings are quite promising. An article published in "Nature Communications" suggests that the first evidence has already been found.

The answer lies in the protein OTOP1, which detects sour taste. This protein is located in the cell membrane and forms an ion channel through which hydrogen ions enter the cell. Hydrogen ions are components of all acids, and when we taste sour foods, they reach the tongue thanks to the OTOP1 protein.