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.