Many people recognize the five basic tastes as sweet, sour, salty, bitter, and umami, but scientists claim to have found the sixth. Dr. Emily Liman from the University of Southern California conducted a study and discovered it is ammonium chloride. It is a salt common in some Scandinavian candies that simulates the tongue’s “sourness receptor.”
Learning about a sixth taste detected by our tongues seems trivial, but not for scientists. They recognize we didn’t develop that ability as a mere coincidence. Instead, it may have evolved to detect ammonium so we wouldn’t consume this hazardous substance. Also, detecting the sixth sense differs among animals, depending on their dietary habits at ecological niches.
This article will discuss the sixth taste we can discern, ammonium chloride. Later, I will elaborate on the fifth and the alternative sixth taste because most readers may not be familiar with them.
How did scientists discover the sixth taste?
Scientists have known for decades that the tongue responds strongly to ammonium chloride. As mentioned, Scandinavian regions call it salmiak salt and use it as an ingredient for salt licorice candy.
However, despite extensive research, experts have not discovered the specific tongue receptors that detect ammonium. Fortunately, LIman and her research team may have found an answer.
Previously, they discovered the protein that detects sour taste called OTOP1. It sits within cell membranes and forms a path for hydrogen ions moving into the cell.
Hydrogen ions are the key component of acids, which are abundant in sour foods like lemons and vinegar. These ions move through the OTOP1 channel into taste receptor cells.
Liman and other researchers knew ammonium chloride could affect the concentration of acids by shifting hydrogen ions. This substance releases small amounts of ammonia that raise the pH level, reducing hydrogen and making a cell more alkaline.
Thus, they inferred that substance may trigger OTOP1. They tested this hypothesis by introducing the OTOP1 gene into lab-grown human cells so they produce the OTOP1 receptor protein.
Next, they exposed the cells to ammonium chloride to check the responses. “We saw that ammonium chloride is a really strong activator of the OTOP1 channel,” Liman stated.
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“It activates as well or better than acids,” it added. Then, they confirmed their findings by testing it on regular mice and those that can’t produce OTOP1.
Taste bud cells from ordinary mice exhibited a sharp reaction when they had ammonium chloride. Conversely, those lacking OTOP1 didn’t react to the substance.
“It shows that the OTOP1 channel is essential for the behavioral response to ammonium,” Liman remarked. “Ammonium is found in waste products,” she explained, “so it makes sense we evolved taste mechanisms to detect it.
What are the fifth and sixth tastes?
You might be familiar with the fifth taste, Umami, but most can’t define it. Fortunately, Japanese food company Ajinomoto has extensive research on umami.
It says it was first discovered in 1908 when Dr. Kikunae Ikeda ate a bowl of kelp broth called kombu dashi. He noticed the savory flavor differed from sweet, sour, salty, and bitter.
He named the flavor “umami,” which roughly translates to “essence of deliciousness.” Later, he attributed the taste to glutamate. In 2002, scientists pinpointed umami taste receptors on the human tongue.
Most describe umami as the “meaty, savory deliciousness that deepens flavor.” You can taste it in protein-rich foods like pork, beef, shellfish, and fish. Also, you can add it with the following condiments:
- Ketchup
- Truffle oil
- Ranch dressing
- Soy sauce
- Miso
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There was a sixth taste before the discovery of our reaction to ammonium chloride. Ajinomoto discovered it in the 1980s and called it kokumi, which means “rich taste.”
It is the “sense of richness, body, and complexity some compare to how wines age and improve over time.” Ironically, Kokumi substances have no taste but make other foods taste better.
Conclusion
Scientists say they discovered the sixth taste our tongues perceive, ammonium chloride. It is often in waste and hazardous products. Hence, it could be a survival adaptation.
In other words, we may have developed an ability to taste ammonium chloride to avoid eating harmful substances and continue living. However, Dr. Emily Liman admits she needs more research to confirm her findings.
Get more information about this study on the Nature Communications website. Learn more about the latest digital tips and trends at Inquirer Tech.