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The Fifth Taste — New Hope For Poor Appetites
It has been common knowledge that there are four basic tastes1: sweet, sour, salty, and bitter. Right?
Not any more. A fifth taste was discovered very early in the twentieth century, but was not recognized officially until the year 2000. It was named “umami” by the Japanese scientist who isolated it, and that name is now official. [Note added by your Newsletter editor: For several reasons it is hard to detect “umami taste” by itself, but that taste is sometimes described as “meaty”.]
The artful use of umami can make mediocre fare taste better, and good food taste great. One substance that has umami taste has been in use in the United States as a flavor enhancer since 1917: MSG, monosodium glutamate, the sodium salt of glutamic acid.
Why should the umami taste exist? One theory holds that tastes guide us toward healthy food choices -- bitter and sour help us avoid dangerous substances, while sweet and salt attract us to sources of needed energy. Because glutamic acid is the most abundant amino acid in animal protein, umami perception could be a meat-protein-seeking mechanism. This theory is consistent with the fact that carnivores and omnivores respond positively to umami, while herbivores are indifferent or even repelled2.
The clearest proof that something is a basic taste would be the discovery of a physical receptor on the tongue, that produces the sensation. The receptors for sour and saltiness are well understood. Controversy lingers about bitter, and there appear to be multiple sweetness mechanisms.
Early in 2000, work at the University of Miami provided definitive evidence that an umami receptor exists.
Many elderly people stop eating well because they have largely lost their sense of taste and smell due to age, disease, or the side effects of medications. Susan Schiffman, of the department of psychiatry at Duke University Medical Center, uses various flavorings and umami substances to improve the diets of old people and medical patients. By selectively flavoring nutritious foods like vegetables, Ms. Schiffman says, she can alter the mix of foods that these people choose to eat. A growing awareness of umami’s role in the flavor and pleasurable sensations of food is changing the way food processors, nutritionists, and chefs think about what they do.
Based on the February 9, 2001 article by Thomas Maeder on the Web site “Redherring.com”
1. Taste is what our tongue tells us: sweet, sour, and so on. It is not the same as flavor, because flavor includes smell. Without smell you would, for instance, be unable to distinguish raw potato from raw apple if you put a slice, unseen, into your mouth.
2. Carnivores are meat-eaters such as cats; Herbivores, such as cows, eat only vegetable matter; Omnivores, such as humans, eat both.
W. A.. Shapiro
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