How Umami Works

The Discovery of Umami
Dashi fish stock often flavors Japanese ramen broth.
Dashi fish stock often flavors Japanese ramen broth.
© Studio Eye/Corbis

People enjoyed umami long before they identified it. Two thousand years ago, for instance, Romans enjoyed garum, a sauce made by fermenting fish until it liquefied [source: Koetke].

The turning point in unmasking umami as a taste came in 1907, when Kikunae Ikeda set out to unlock the secret of dashi [source: Koetke]. Dashi, a staple in Japanese cuisine, is a fish stock made by simmering flakes of dried bonito, a type of tuna, in a broth made from the seaweed kelp, or kombu. It's a main ingredient in numerous traditional dishes, including miso soups (made with fermented soybean paste) and sauces for buckwheat soba noodles and tempura-battered vegetables [source: Wang]. Ikeda noticed dashi imparted the same full-bodied savoriness he'd tasted in tomatoes, asparagus and other foods while studying in Germany [source: Ninomiya]. It was this taste and textural experience that he would later name umami.

Ikeda was no ordinary foodie: By the time he undertook his investigation, he was a chemistry professor at the Imperial University of Tokyo. Accordingly, he began with a chemical analysis of dried kelp. Through water extraction and crystallization, Ikeda flushed out and sorted through its various components. He discovered several salts, including potassium chloride and sodium chloride (table salt) [source: Lindemann]. But as a chemist and dashi aficionado, he knew these were not the source of umami. Finally Ikeda isolated the compound that met both the taste and chemical criteria: monosodium glutamate, or MSG [source: Kenzo]. As the name denotes, MSG is sodium salt formed from glutamic acid. Glutamic acid is an amino acid and amino acids are the building blocks of protein.

A few years later, one of Ikeda's students would identify the main umami component in the dried bonito: inosinate. Inosinate belongs to a class of proteins called nucleotides [source: Kenzo]. Around 1960, scientist Akira Kuninaka identified guanylate, another nucleotide in shiitake mushrooms, as a third contributor to umami. Equally important, Kuninaka found that the relationship among these three ingredients is synergistic: They work together to heighten the umami impact exponentially [source: Ninomiya].

That's the umami backstory. To understand how it works to enhance food flavor, we offer the following short course in taste physiology – a tour of the tongue and beyond.

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