When we taste a food, humans We distinguish between sweet, bitter, salty and sour. four basic tastes that combine in our nervous system to configure what is commonly we call it ‘taste’. This complex sensory experience, configured in the brain, allows us to provides information about what we find enjoyable (nothing is written against taste) and induces us to consume certain foods. However, for some animals, this sense is not just a matter of preferencesbut of survival, as it is indicative of the chemical peculiarities of a given food that may mean the difference between life and death.
The key is in the PH
pH, the scale of acidity or basicity of a substance (the quality of the base), plays a role an essential role for living organisms, given that many biological processessuch as food breakdown and enzymatic reactions, they need the pH level to be correct. PH stands for ‘hydrogen potential’ and specifically indicates the amount of hydrogen ions available in a substance. Thus, the greater the amount of available ions, the more acidic it will be and vice versa. Thus, a high pH indicates that the substance is alkaline, while a low pH tells us that it is acidic. The scale is between 0 and 14, with which the neutral PH is considered the one with the value 7.
human beings are familiar with the sour tastethat allows us to perceive these very low pH values, little is known about how other animals perceive bases at the opposite end of the pH spectrum: the alkaline. The detection of acids and bases frequently present in foods is important because they can significantly influence the nutritional or toxic properties of foods. And it is that a very high pH can be harmful, not only for flies but also for humans, which can cause health problems such as muscle spasms, nausea and numbness.
Alkaline, the sixth taste
A new investigation carried out by the Monell Chemical Senses Center, an organization dedicated to the investigation of new flavors, has identified a new method to detect this high pH based on the study of the behavior of fruit flies. (Drosophila melanogaster). Researchers have discovered that these insects can distinguish alkaline substances because they have a taste receptor for high pH. In other words: they found an sixth taste In addition to the four previously described and the so-called umami, discovered decades ago.
“Our work has settled the debate about whether there is a taste for alkaline foods.” Yali Zhang, biochemist.
A team of scientists, led by Yali Zhang, a biochemist at the Monell Center and lead author of the recent discovery, published in the specialized journal Nature’s Metabolism, discovered a gene coded as CG12344, which they named alka, It is expressed in taste receptor neurons (GRNs) of flies, the equivalent of mammalian taste receptor cells.
An investigation based on fruit flies has shown the existence of the alkaline taste. The new flavor adds to the four classics (sweet, bitter, salty and sour) and umami, added later.
To carry out the experiment, the scientists used the CRISPR gene editing technique, the so-called ‘genetic scissors’, to knock out the gene alka. When confronted with neutral foods versus alkaline foods, wild flies chose neutral pH foods. On the contrary, the genetically modified they had lost the ability to discriminate alkaline foods.
In short, Dr. Zhang and his team found that fruit flies have a taste receptor capable of detecting this high pH and therefore a new taste: alkaline. In the future, his team intends to study whether analogous high-pH detectors exist in mammals, but for now, “our work has settled the debate about whether there is a taste for alkaline things,” Zhang said. “It definitely exists,” says the expert.