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Interviewees: Elliot Prag, Natural Gourmet Institute
Until recently scientists used to say we could sense only four basic tastes; sweet, salty, bitter and sour. But chefs worldwide have long known about umami taste.
One hundred years ago, a Japanese chemistry professor, Kikunae Ikeda recognized that the dominant taste in a soup base called dashi was distinct from the four officially named basic tastes. Dashi is made by boiling a seaweed called kombu. Ikeda isolated the source of the taste and identified it as glutamate, a type of amino acid.
He called it “umami,” derived from the Japanese word “umai,” meaning delicious. Ikeda developed a method to make a crystallized form of it called monosodium glutamate or MSG. The Ajinomoto company subsequently mass-produced the product. But it took many years for the larger scientific community to acknowledge umami as a basic taste.
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In 2002, molecular biologist Xiaodong Li, from Senomyx, Inc. discovered umami receptors on the human tongue. It was only then that scientists began to acknowledge umami as an official basic taste. Glutamates are found naturally in many protein rich foods like meats and seafood but also in tomatoes, shitake mushrooms, fermented products like soy sauce and certain aged cheeses.
But it was still a mystery how glutamates acted on the receptors. Now Li’s team has figured it out. Li studied umami receptors in cell cultures. He discovered that the key part of the umami receptor is shaped like a clamshell and when glutamate is added, the clamshell shuts.
But there was another part to Li’s study. There are certain chemicals that enhance umami taste including IMP and GMP. Many packaged food manufacturers add these enhancers to products that contain glutamates to strengthen the umami taste, even though the mechanism was unknown. Li had already seen the effects of these enhancers in his studies of cell cultures. But now he found out how they work. When the enhancers are mixed with glutamates, the clamshell part of the receptor shuts even tighter.
Li says that this research can help the company create more umami ingredients and enhancers. Even before this study, Senomyx had four patented umami flavorings that are used in packaged foods.
But you don’t necessarily need to add processed ingredients like MSG to get more umami into your meals. FIRST Prag, who is an instructor at Natural Gourmet Institute, says there are many natural ways to get umami flavor in the kitchen, without adding packaged glutamates.
“If you make a beef stew, if you make chicken soup, if you make a mushroom dish, if you used an aged cheese in what you were cooking you would achieve this flavor very easily,” explains Prag.
PUBLICATION: Proceedings of the National Academy of Sciences, December 30, 2008
RESEARCH FUNDED BY: Senomyx, Inc.
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