‘Umami’ Distinct Way To Describe Flavor

If tomatoes and peas are among your favorite vegetables, you love mushrooms and you keep a container of grated Parmesan on hand, chances are you are a big fan of umami.

Still unfamiliar to most Americans (but perhaps not for long), “umami” is a Japanese word that translates, vaguely, as “deliciousness.”

But the Japanese take it much further, using it to describe a fifth taste, one that is a bit more difficult to describe than the basic four: salt, sweet, sour and bitter.

Scientists are studying umami to understand what makes some people recognize and appreciate flavors that others cannot.

Their studies may shed new light on the role that glutamates - the amino acids that are in all foods described as having umami - play in carrying flavor and stimulating the appetite.

The most direct way to sample the umami taste is to sip a bowl of miso soup or to eat some sauteed mushrooms. If you would describe what you are tasting as “brothiness” for the soup or “meatiness” in the mushrooms, that is umami.

“There is a growing consensus that umami is in fact distinct, that there is something different about it from all other tastes,” said Dr. Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia.

Scientists have recently discovered that there are specific receptors in the mouth that seem designed to respond only to glutamates.

At the International Symposium on Olfaction and Taste in San Diego last July, Stephen Roper, a professor of physiology and biophysics at the University of Miami, compared the effect of glutamates on these receptors to turning a key in a lock that then starts an engine.

“The glutamate is the key, the receptor is the lock and now we’re trying to figure out exactly what happens when the key is turned,” Roper said.

If umami really is a distinct taste, why is it so elusive? After all, the classic big four of salty, sour, bitter and sweet require no scientific explanation: They are right there when you taste, for example, soy sauce, lemons, quinine or candy canes.

“The idea that there are only four tastes is like a religion,” said Professor Michael O’Mahony of the University of California at Davis. “It’s embedded in people’s heads. So when people are trying to describe the taste of something or other, they latch on to this idea that they have to use just four words.”

O’Mahony was attracted to the umami concept precisely because it could not be described adequately in English. So he set up experiments in which American and Japanese students were asked to describe the taste of glutamate.

The Americans’ descriptions were all over the map. “Salty” was the most common term employed; others were “beef bouillon,” “fishy,” “hamburger grease” and “seaweed.” The Japanese students described the taste as either “umami” or “Ajinomoto,” the name of a Japanese glutamate-based food additive.

Umami is likely to have somewhat of an uphill battle in this country in terms of image. The glutamate most familiar to Americans, a salt of glutamic acid called monosodium glutamate (MSG), has a bad reputation here. A common ingredient in Chinese restaurant food, MSG can cause hot flashes, tingling, tightness in the face and a vague feeling of pressure in the muscles.

Like salt, MSG brings out the inherent flavors in foods. In fact, umami has a quite remarkable ability to enhance flavor. “Umami can produce a certain fullness, a complexity, a depth of flavor when added to food,” said Patricia Keane, a senior consultant at Arthur D. Little in Boston, where umami has been studied since the 1940s. “It is not only a taste, but a kind of mouth feel.”

Despite the frequent description of umami as meaty, many foods - including mushrooms, tomatoes, peas and Parmesan cheese - have a higher level of free glutamate than an equivalent amount of beef or pork. This explains why foods that are cooked with mushrooms or tomatoes seem to have a fuller, rounder taste than when cooked by themselves.

“Umami stimulates appetites in all cultures all across the board,” Roper said. “Indeed, it seems very likely that glutamate drives the appetite for protein, just as the sweet taste drives the appetite for carbohydrates and the salt taste for minerals.”