24 August 2006

That Sour Taste

Scientist Charles Zuker and his colleagues had just figured out how our tongues are able to taste any sour taste. He has zeroed in on the action of a receptor called PKD2L1, which seems to be the receptor which communicates the sour taste.

What remains baffling to the scientists is "why a sour receptor would come to be." They can explain 'bitter' as our way of avoiding poisonous substances, and 'sweet' as our way of knowing what to eat when we need a boost in energy. But sour??? They still don't know why we would need to detect sour food items.

Not all sour foods are bad. Most girls I know like the sour taste. They even like their mangoes green just to have that sour taste. Why do we need the sour taste? I can venture a guess: maybe we need to detect Vitamin C, too.

How about you? Any good guesses?

5 reactions:

bayi said...

The sour taste brings out our saliva and digestive juices. When we eat Indian rice, we are usually offered something sharply sour so that we can stimulate our digestive juices to help digest the curry. The saliva helps to clean our mouth and teeth. My "explanation" is just a guess!

Emer said...

Even the other tastes can also evoke the release of salivary enzymes. The medical term is called a gustatory response, Bayi. Your guess is good but I think there is still more to reason why we are able to detect sour tastes.

Anonymous said...

My guess is that we have them so we can taste whether or not the food or drink we are about to comsume is off or not ripe yet..you think..if we ate fruit that wasnt ripe or was off..it has a taste of sour and bitter..both of which is need to tell us not to eat it..having something sour causes a reaction in the body, anything from the saliva to eyes watering, to having cringes..i think its something we have developed from millions of yrs ago when we needed it to tell us not to eat certian foods, otherwise we would become sick, but in our days..food which is sour, has most likely been made sour for the unusual reaction and taste..

jhay said...

I've read this news item last week. It noted that we humans are the only kind of our species that have a taste for sour food. It is an indication of high acidity in food stuffs like unripe fruit etc. but I guess since we evolved intelligent brains that can has gotten the hang of sour foods and made it to our liking.

Anonymous said...

I think that our saliva is very sensitive to the sour taste and that is why our saliva bleeds from our tongue. we all know that that sour taste in our mouthis detected by our taste buds i did a report on this:
Scientists and researchers may have finally revealed the secret, of that sour taste in your mouth when you eat a lemon or something that is labeled sour. A protein called PKD2L1 might help solve the mystery.
Scientists began by estimating that sour-sensing proteins would have regular traits with proteins that allow us to sense other tastes. These molecules, called receptors, are imbedded inside some tongue cells. Tongue cells contain a receptor that senses just one type of flavor. Perhaps one cell might have a sweet receptor, while another cell responds to only bitter flavors. PkD2L1 was zeroed in on scientists. PKD2L1 caught their eye because it appeared to be a specialized protein in taste bud cells. At the same time, it did not show up in cells that sensed sweet, bitter, or umami flavors. Researchers then created a strain of mice that did not make the
PKD2L1 protein. The tests on the mice’s nerves showed that the mice responded to only the non-sour tasting flavors. The scientists gave them citric acid or vinegar, nothing happened.
The mice “were completely insensitive, just like we were dabbing their tongues with water,” says research-leader Charles S. Zuker of the University of California, San Diego. This discovery may have eventually help chemists make foods less sour, from the inside out. The scientists did this to solve the mystery of the bitter taste in your mouth when you eat sour foods.