Monosodium glutamate (MSG), also known as sodium glutamate, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids. Glutamic acid is found naturally in tomatoes, grapes, cheese, mushrooms and other foods. MSG is used in the food industry as a flavor enhancer with an umami taste that intensifies the meaty, savory flavor of food, as naturally occurring glutamate does in foods such as stews and meat soups.
MSG was first prepared in 1908 by Japanese biochemist Kikunae Ikeda, who was trying to isolate and duplicate the savory taste of kombu, an edible seaweed used as a base for many Japanese soups. MSG balances, blends, and rounds the perception of other tastes. MSG is commonly found in stock (bouillon) cubes, soups, ramen, gravy, stews, condiments, savoury snacks, etc. After 1968, it became known for its use in Chinese restaurants.
The U.S. Food and Drug Administration has given MSG its generally recognized as safe (GRAS) designation. A popular misconception is that MSG can cause headaches and other feelings of discomfort, known as "Chinese restaurant syndrome," but blinded studies fail to find evidence of such a reaction. The European Union classifies it as a food additive permitted in certain foods and subject to quantitative limits. MSG has the HS code 29224220 and the E number E621.