Monosodium glutamate

Flavor enhancer (621 or E621)

Monosodium glutamate (MSG), also known as sodium glutamate, is a sodium salt of glutamic acid. MSG is found naturally in some foods including tomatoes and cheese in this glutamic acid form, and is used in cooking as a flavor enhancer that intensifies the umami flavor of food, as naturally occurring glutamate does in foods such as stews and meat soups. MSG was first extracted in 1908 by Japanese biochemist Kikunae Ikeda, who tried to isolate and duplicate the savory taste of kombu, an edible seaweed used as a broth (dashi) ingredient in Japanese cuisine.

From Wikipedia, under CC BY-SA. More on occurri.