Umami and the Fifth Taste

For much of the twentieth century, Western food science recognized only four basic tastes: sweet, sour, salty, and bitter. A fifth taste, now called umami, had already been identified decades earlier by Japanese chemist Kikunae Ikeda, but it took much longer to gain acceptance outside Japan. In 1908, Ikeda became curious about the deep, savory flavor of dashi, a broth made from kombu, a type of edible kelp. Through chemical analysis, he isolated glutamate, a naturally occurring amino acid, as the compound responsible for the broth's distinctive taste, and he coined the word umami to describe it, combining Japanese words roughly meaning "pleasant" and "taste." For most of the following century, many Western scientists remained skeptical that umami represented a genuinely separate taste rather than simply an intense version of saltiness. That skepticism began to fade in the early 2000s, when researchers identified specific taste receptors on the tongue, formed by proteins named T1R1 and T1R3, that respond directly to glutamate and closely related compounds. This discovery gave umami the same physiological basis already established for the other four tastes. Umami now appears on the standard list of basic tastes in most nutrition and food science curricula, and its presence is noted in foods ranging from aged cheese and ripe tomatoes to mushrooms, soy sauce, and cured meats.