Monosodium glutamate (MSG) is a flavor enhancer classified as food additive E621. It is the sodium salt of glutamic acid — a naturally occurring amino acid found in many foods including tomatoes, aged cheeses, mushrooms, and fermented products. Commercially, MSG is produced by bacterial fermentation of sugars. Its primary technological function is to enhance and intensify the savory (umami) taste of food products. It can also serve as a partial salt substitute in reduced-sodium formulations.
Applications and dosage
MSG is used in a wide range of food products:
- Food concentrates (instant soups, bouillon cubes, seasoning mixes) — up to 5,000 mg/kg
- Dietary products as a salt substitute — up to 5,000 mg/kg
- Ready-to-eat snacks (flavored crackers, croutons, chips, marinated herring) — up to 10,000 mg/kg
Physical and chemical properties
Chemical formula: NaC₅H₈NO₄·H₂O. CAS number: 142-47-2. Molecular mass: 169.1 g/mol (anhydrous), 187.1 g/mol (monohydrate). Appearance: white crystalline powder with no distinct odor. Melting point: 232 °C. Water solubility: ≥100 g/L at 20 °C, with maximum solubility up to 740 g/L. MSG dissolves readily in water, making it easy to incorporate into liquid-based food systems.
Safety considerations
MSG has been extensively studied and is classified as “generally recognized as safe” (GRAS) by the U.S. FDA and approved by the European Food Safety Authority. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has not set an ADI limit for MSG. However, some individuals may experience transient symptoms after consuming large amounts — a phenomenon sometimes called “Chinese restaurant syndrome.” Risk code R20/21/22 applies to the pure substance, indicating it can be harmful through oral, respiratory, and skin exposure at industrial concentrations. MSG can be produced from genetically modified raw materials.
Find more information about food additives and flavor enhancers in the articles below.