Monosodium Glutamate (MSG)

What is Monosodium Glutamate?

Monosodium glutamate, often abbreviated to MSG, is a sodium salt of glutamic acid. The chemical formula of MSG is C5H8NO4Na and its IUPAC name is sodium 2-aminopentanedioate. Since it is known to intensify meaty flavours in food, monosodium glutamate is widely used as a flavour enhancer in the food industry.

This compound was first produced by the Japanese chemist Kikunae Ikeda in the year 1908. At room temperature, MSG exists as a crystalline solid which is white in colour. It does not have any distinct odour.

Monosodium Glutamate

Crystals of Monosodium Glutamate (MSG)

Among the sodium, magnesium, potassium, and calcium salts of glutamic acid, MSG is the most soluble in water. Monosodium glutamate dissociates into sodium cations (Na+) and glutamate anions (C5H8NO4) when dissolved in water.

Structure

MSG molecules feature an ionic bond between Na+ and C5H8NO4. The structure of a monosodium glutamate molecule is illustrated below.

Monosodium Glutamate Structure

Structure of Monosodium Glutamate

In solid MSG, the glutamate ion exists in its zwitterion form – O(C=O)CH(NH3+)(CH2)2(C=O)O.

Preparation

The three most common methods of producing monosodium glutamate are listed below.

  • Hydrolysis of some vegetable proteins in the presence of hydrochloric acid.
  • Chemical synthesis with the help of acrylonitrile (CH2CHCN).
  • A bacterial fermentation process involving starch or molasses.

The majority of MSG production is done through bacterial fermentation. Commercial samples of this compound are usually in the monohydrate form.

Properties of MSG

Chemical Data

Monosodium Glutamate C5H8NO4Na
Molar Mass Anhydrous: 169.11 grams/mole; Monohydrate: 187.12 grams/mole
Melting Point 232oC
Boiling Point Decomposes

Physical Properties

  • This compound is solid at room temperature and has a white, crystalline appearance.
  • Monosodium glutamate is odourless.
  • A saturated solution of MSG in water has a density of 26.2 grams per cubic centimetre at a temperature of 20o
  • MSG is highly soluble in water; its solubility in water corresponds to 740 grams/litre.

Chemical Properties

  • When heated to temperatures above 232oC, this compound decomposes to release toxic fumes containing oxides of nitrogen and sodium.
  • Solutions of monosodium glutamate have pH values ranging from 6.7 to 7.2.
  • When cooled to temperatures below -8oC, this compound crystallizes as a pentahydrate.

What are the Uses of Monosodium Glutamate?

Monosodium glutamate has an umami taste and it intensifies meaty flavours when added to certain foods. Therefore, one of its primary applications is in the food industry. Some other important uses of MSG are listed below.

  • This compound is used in several canned food products and spice blends.
  • MSG is often added to tobacco in order to enhance its taste.
  • It also finds use in the treatment of hepatic coma.
  • MSG is an important component of several instant ramen noodle products.

Monosodium glutamate has been associated with several symptoms such as headaches, tingling sensations, and burning sensations. These symptoms are collectively referred to as the “Chinese restaurant syndrome”. However, the data from several studies suggest that there is no link between this syndrome and MSG. This compound is a permitted food additive in most countries.

To learn more about monosodium glutamate and other sodium compounds (such as sodium thiosulfate), register with BYJU’S and download the mobile application on your smartphone.

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