[Chemistry Class Notes] Monosodium Glutamate Pdf for Exam

Monosodium glutamate (MSG) is a white crystalline substance, at room temperature, which is used for enhancing flavors in certain food items. MSG is also commonly known as monosodium L-glutamate or sodium glutamate or Ajinomoto. MSG is a sodium salt of glutamic acid. The IUPAC name of monosodium glutamate or MSG is sodium 2-aminopentanedioate and the chemical formula is C5H8NO4Na. MSG as a compound does not have any distinct odor. In terms of solubility, it dissolves better than other salts of glutamic acid such as sodium, magnesium, or potassium. When it dissolves it separates into cations, which are Na+, and anions, which is C5H8NO4⁻. 

Chemical Properties of MSG

There are several distinctive properties of monosodium glutamate. Some of the chemical properties of monosodium glutamate are listed below:

• The IUPAC name for MSG is (2S)-2-amino-5-hydroxy-5-oxo-pentanoate

• The molecular formula is C5H8NO4Na

• The molecular mass of MSG is 169

• Its melting temperature is 225oC

• When heated or melted, it decomposes and releases oxides of nitrogen and sodium in the form of toxic fumes. 

• When cooled down at temperature around -8oC, it crystallizes as a compound known as pentahydrate.

• It is highly soluble in water

• The pH level of MSG ranges from 6.7 to 7.2.

• MSG corresponds to the deprotonation of the a-carboxylic group. This group is also known for having the most acidic hydrogen.

Physical Properties of MSG

MSG is also quite popular in the Indian culture as it is added in the preparation of many food items. Some people do not recommend the use of MSG in food as it can affect their health or the child’s development. Therefore, it is important to have a thorough understanding of compounds that are so popular and common in our day-to-day lives. 

Since we are discussing the properties of monosodium glutamate, it is important to specify some distinctive physical properties of monosodium glutamate. Some of these properties are mentioned below:

• It is a solid compound.

• In terms of solubility, MSG is highly soluble in water but not insoluble in organic solvents. The solubility level of MSG in water corresponds to 740grams for every liter.

• At room temperature, it has a white, crystal-like appearance.

• MSG has no odor or smell. Some might say that it has a peptone like odor. 

• The taste of MSG refers to “Umami”.

• When MSG is dissolved in water, it develops the shape of rhombic prisms.

• The density of MSG is 26.2 gram per cubic centimeters when the MSG solution is saturated in water at a room temperature of 20oC. 

Understanding How is MSG Produced

There are three common methods of preparing or producing monosodium glutamate. 

1. The first process is called hydrolysis. In this method, hydrochloric acid is added to some vegetables, and the process of hydrolysis is then conducted in order to produce MSG. 

2. The second common method is through chemical synthesis. In order to prepare monosodium chloride through chemical synthesis, acrylonitrile is used. The molecular formula for acrylonitrile is CH₂CHCN. 

3. The third and the most common process for preparing MSG is bacterial fermentation. This process requires starch or molasses and ammonium salts. 

For commercial or large scale production, MSG is prepared in the monohydrate form. 

MSG Monosodium Glutamate Other Names

MSG, commonly known as monosodium glutamate is largely responsible for that irresistible taste. The other names for MSG include 

Fun Fact

MSG has been found to stimulate the taste bud receptors of the palate that conveys a brain signal because of which the taste of a food item gets intensified or enhanced.