June 1, 2006 An exhibit at San Francisco's Exploratorium explains the science of cooking and eating, and in particular how we taste food. Our sense of taste comes from a combination of smell receptors in the nose and five types of taste receptors on the tongue, one of which was only discovered in 2000. The biological basis of our preferences for particular foods is still somewhat a mystery.
SAN FRANCISCO--Why do some people like these foods and others don't? Science may have many of the basics of the human body down, but our sense of taste and smell are still somewhat of a mystery.
What makes some of us scrunch our nose at certain foods is a question biologists have been trying to figure out.
"Most people don't realize that most of what we call taste -- enjoying a meal or a fine wine -- is actually smell," Karen Kalumuck, a biologist at San Francisco's Exploratorium, tells DBIS.
Kalumuck says 75 percent of what we call taste is due to what we smell. "Think about when you've a cold. You've got this stuffed up nose. I mean, what did things taste like? Not so great," she tells DBIS. "That's really because we can't have the odorant molecules meet up with the sensory receptors in the nose and transmit that information to the brain."
You can see how the nose and the mouth work together if you pinch your nose and eat a piece of candy, then unplug your nose while it's still in your mouth.
The nose has 5 million odor receptors that can detect 10,000 unique odors. On the tongue, there are taste buds. Inside each bud could be 50 to 100 taste receptor cells. Each receptor cell detects one of five different types of taste, sweet, sour, bitter, salty and umami.
What's umami? It detects the amino acid glutamate and was added to the list in 2000.
"Most ... have probably experienced glutamate in the form of MSG," Kalumuck says.
Also, spicy foods are not part of our taste or smell receptors ... They stimulate our pain receptors. So people who love spicy have a high tolerance for pain! And taste is all genetic! Your genes determine the type and number of sensors you have, so you can blame mom or dad if you don't like your food.
Kalumuck says you can learn to enjoy foods that might -- at first bite -- taste unpleasant.
BACKGROUND: An exhibit at the Exploratorium in San Francisco discusses the science behind cooking and eating. One section in particular reveals how odor molecules can react with our senses as part of the eating experience. This in turn may play a role in determining why some people like or dislike certain foods -- like anchovies on pizza.
HUMAN TASTE TEST: Taste is the ability to response to dissolved molecules and ions called tastants, which humans detect via taste receptor cells, clustered into taste buds. The tongue has about 10,000 taste buds. When these detect food particles, they send signals to the brain carrying information about their "taste." Each taste bud contains 50-100 taste cells, representing the five taste sensations: salty, sour, sweet, bitter and umami (the response to acidic salts like MSG, often used as a flavor enhancer in Asian dishes, processed meats, and processed cheeses).
Each taste cell has receptors that bond to specific molecules and ions response for the various taste sensations, connected to a sensory neuron leading back to the brain. So taste -- like all sensations -- resides in the brain. That's the reason different people like different things. Although a single cell may have several types of receptors, one may be more active than the others, so certain tastes will be preferred by that individual. Also, no single taste cell contains receptors for both bitter and sweet tastants.
THE NOSE KNOWS: Our sense of taste is partially enhanced by smell, which is why food may taste bland when we have a cold that blocks the nasal passages. Nerve receptor cells within the nose detect odors carried into the organ by air, and transmit signals to the brain through the olfactory nerve.
LITTLE FISH: Anchovies are small saltwater fish related to herring, usually found in coastal Italy. They can be cooked fresh, but are usually sold packaged in salt, tinned, or jarred in oil, or as a paste in tubes. They are used not just as a pizza topping, but also in the classic Caesar salad dressing -- and sometimes adorn the salad itself.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.