In 1908 Professor Kikunae Ikeda (1864—1936), College of Science, Tokyo Imperial University, Japan, isolated glutamate, one of the natural amino acids, from seaweed broth. 2300 years before this, Aristotle described the four tastes: sweet for sugar, salty for sodium chloride, sour for acid, and bitter for alkaloids. The fifth taste, the unami taste, is the indicator for proteins and nucleic acids.
Two other umami compounds were isolated later in Japan.
Ikeda found that humans can sense glutamate at a concentration as low as 0.01 % in water—far lower than the detection limit of sodium chloride and sugar—and that it is essential for a meal to taste good. He also found that sodium glutamate and sodium chloride synergistically enhance the taste of a meal.
Parmigiano reggiano contains a large amount (1.7 wt %) of glutamate, matured tomato > 2 % of its dry weight, and half of the amino acid content in human breast milk is glutamate. Today it is known that humans have a glutamate-receptor protein on the surface of their tongue and stomach.
In 1909, in collaboration with Ikeda, Saburosuke Suzuki started producing a seasoning on a commercial basis. A century later “Ajinomoto” has developed into a global product, and is now used by 800 million people in about 100 countries.
- One Hundred Years since the Discovery of the “Umami” Taste from Seaweed Broth by Kikunae Ikeda, who Transcended his Time,
Chem. Asian J. 2011.