Monosodium Glutamate (MSG)
Monosodium glutamate, sodium glutamate, flavour enhancer 621, EU food additive code: E621, HS code: 29224220 (IUPAC name 2-aminopentanedioic acid. Also known as 2-aminoglutaric acid), commonly known as MSG, Ajinomoto, Vetsin, or Accent, is a sodium salt of glutamic acid. MSG is a food additive and it is commonly marketed as a "flavour enhancer".
Although traditional Asian cuisine uses flavour-enhancing ingredients which contain high concentrations of MSG, it was not isolated until 1907. MSG was subsequently patented by the Japanese Ajinomoto Corporation in 1909. In its pure form, it appears as a white crystalline powder; when dissolved in water (or saliva) it rapidly dissociates into sodium cations and glutamate anions (glutamate is the anionic form of glutamic acid, a naturally occurring amino acid).
Under Standard conditions for temperature and pressure, MSG is stable, but it reacts with strong oxidizing agents. Two chiral enantiomers exist for monosodium glutamate, but only the naturally occurring L-glutamate form is used as a flavour enhancer.
The Ajinomoto Company was formed to manufacture and market MSG in Japan; the name 'Ajinomoto' means "essence of taste". It was introduced to the United States in 1947 as Ac'cent flavor enhancer.
Modern commercial MSG is produced by fermentation of starch, sugar beets, sugar cane, or molasses. About 1.5 million metric tons were sold in 2001, with 4% annual growth expected. MSG is used commercially as a flavour enhancer. Once stereotypically associated with food in Chinese restaurants in America, it is now found in some common food products consumed in the US.
Only the L-glutamate enantiomer has flavour-enhancing properties. Manufactured MSG contains over 99.6% of the naturally predominant L-glutamate form, which is a higher proportion of L-glutamate than found in the free glutamate ions of naturally occurring foods. Fermented products like soy sauce, steak sauce, and Worcestershire sauce have comparable levels of glutamate as foods with added MSG. However, glutamate in these brewed products may be composed 5% or more of the D-enantiomer.
