Monosodium glutamate, also known as sodium glutamate and MSG, is a sodium salt of the naturally occurring non-essential amino acid glutamic acid. It is used as a food additive and is commonly marketed as a flavour enhancer. It has the HS code 29224220 and the E number E621. Trade names of monosodium glutamate include Ajinomoto, Vetsin, and Accent. It was once predominantly made from wheat gluten, but is now mostly made from bacterial fermentation; it is acceptable for celiacs following a gluten-free diet.
Although traditional Asian cuisine had often used seaweed extract, which contains high concentrations of glutamic acid, it was not until 1907 that MSG was isolated by Kikunae Ikeda. MSG was subsequently patented by Ajinomoto Corporation of Japan in 1909. In its pure form, it appears as a white crystalline powder which rapidly dissociates into sodium cations and glutamate anions on contact with water (glutamate is the anionic form of glutamic acid).
Modern commercial MSG is produced by fermentation of starch, sugar beets, sugar cane, or molasses. About 1.5 million tonnes were sold in 2001, with 4% annual growth expected. MSG is used commercially as a flavour enhancer. Although once associated with foods in Chinese restaurants, MSG is now used by most fast food chains and in many foodstuffs, particularly processed foods.
- Prepared stocks often known as stock cubes or bouillon cubes.
- Condiments such as barbecue sauce and salad dressings.
- Canned, frozen, or dried prepared food
- Common snack foods such as flavoured jerky, flavoured potato chips (crisps) and flavoured tortilla chips.
- Seasoning mixtures