Posted on 10/19/2009 10:04:13 PM PDT by neverdem
Protein splits carbon dioxide to give fizz its flavor
The light, sparkly fizz of champagne owes its taste to the tongue’s sense of sour. New studies in mice reveal how the tongue tastes carbonation, solving an old puzzle of why some mountain climbers get the “champagne blues.”
Tasting fizz begins with a special protein that’s tethered to sour-sensing taste cells on the tongue, researchers report in the Oct. 16 Science. This protein, the enzyme carbonic anhydrase 4, splits carbon dioxide into bicarbonate ions and free protons, which stimulate the sour-sensing cells.
Scientists have long thought that the taste of carbonated beverages emerged from the physical bursting of bubbles on the tongue, says study author Charles Zuker, a neuroscientist now at Columbia University who did the work while at the University of California, San Diego. But bubbly drinks still taste distinctly carbonated when they are imbibed in a pressure chamber where bubbles don’t burst.
To understand how carbonation fits into the sensory repertoire, Zuker, Nick Ryba of the National Institute of Dental and Craniofacial Research in Bethesda, Md., and their colleagues measured nerve activity in mouse taste cells. When the rodents were given carbon dioxide in the form of club soda or gaseous CO2, their taste cells responded robustly to CO2.
The researchers then genetically engineered mice that were missing one of the five kinds of taste cell—sweet, salty, umami, bitter and sour. Taste-sensing nerves fired in response to carbon dioxide except in the “sourless” mice, pinpointing the role of the sour-sensing taste cells.
Combing through the genes that are turned on in sour-sensing cells, one “rose to the top,” says Zuker. It was the gene encoding carbonic anhydrase 4, one enzyme in an important class that helps maintain appropriate levels of CO2 and acidity in the body.
The researchers also...
(Excerpt) Read more at sciencenews.org ...
Protein splits carbon dioxide to give fizz its flavor, not.
Carbonic anhydrase splits H2CO3, carbonic acid, giving carbon dioxide and water. I feel bad for the author. This story is one of the current favorites.
Dang I’m sure glad you cleared that up. But now I’m going to be up all night calling everyone I know to share this incredible news with them.
Thanks SO much!
Does this mean that we can taste globule warming?
Other sources (e.g. the infamous Wiki) claim that this same anhydrase turns bicarbonate ion into hydrogen ions and carbon dioxide, the hydrogen ions triggering the sour taste characteristic of any acid. Is someone mixing up the two anhydrases, or is this a dual purpose enzyme?
O M G!!
I’ve lost countless hours of sleep worrying/wondering why climbers hate their top-of-the-peak champagne!
I am sooooooo grateful that the mystery is solved, I’m going to bed to rest for the first time in YEARS!
Did we pay for this study?
I don't know. They're calling this one carbonic anhydrase 4. I get the impression they have found at least three other variants. I wouldn't be surprised if there are multiple multifunction enzymes, but folks don't appreciate all the reactions that they catalyze yet.
Does anyone know why carbonated beverages “burn” the esophagus when consumed?
What causes this pain, and why does it increase the longer you drink?
I don't. I just have questions. Does anything give it relief besides not drinking carbonated beverages? Try baking soda or over the counter Pepcid, Zantac or Tagamet.
What causes this pain, and why does it increase the longer you drink?
Maybe it's an inherited trait. Do siblings, mother or father have similar complaints? Maybe it's gastroesophageal reflux disease, GERD, or a hiatal hernia? Consider seeing a gastroenterologist.
I’m speaking in more general terms, here. I don’t have a medical condition, etc...
I believe everyone experiences the carbonated beverage “throat pain,” much like the common icecream headache. (from consuming icre cream too quickly) If you open a fresh can of coke and try to chug it, your throat will begin to hurt more and more the longer you drink.
Why?
I believe everyone experiences the carbonated beverage “throat pain,” much like the common icecream headache. (from consuming icre cream too quickly) If you open a fresh can of coke and try to chug it, your throat will begin to hurt more and more the longer you drink.
Why?
Coka Cola has phosphoric acid. Try club soda.
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