A Taste of Protons

Q.1 Is it possible to use one’s tongue as a subatomic particle detector?
Q.2 If so, would that be a good idea?

According to Professor Stefan Frings, of the Frings Group at Heidelberg University Institute of Zoology, Heidelberg, Germany, it looks as though the answer to both questions is ‘Yes’.
He provides a general overview of the latest discoveries, in Proceedings of the National Academy of Sciences of the United States of America, PNAS December 2010 107 (51) 21955-21956. Drawing attention to the fact that the ability to detect ‘sour’ tastes is one of the least well-understood gustatory talents. But progress has recently been made, and the current view is that the detection of sour tastes is linked to the presence of hydrogen ions in the food. Since a normal hydrogen atom is composed of one proton and one electron, a hydrogen ion (missing its electron) can simply be thought-of as a free proton. Thus the sour-specific cells of mammalian tongues are, in effect, proton detectors. And this is an important, perhaps even life-saving skill – for sometimes, sour (acidic) foods might be dangerous to eat.

“When an animal eats, there is a brief but absolutely vital period during which it must reach a decision as to what to do with the food in its mouth: swallow it or spit it out.”

“Fortunately, the sense of taste has evolved to stand sentinel over the digestive system. It provides last-moment information on the suitability of food, and it enables the animal to come to an almost binary decision: take it! or get rid of it!.

The paper can be found here : The sour taste of a proton current.