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Monosodium glutamate, also known as sodium glutamate, is a sodium salt of glutamic acid.
Monosodium glutamate is found naturally in some foods including tomatoes and cheese in this glutamic acid form, and is used in cooking as a flavor enhancer that intensifies the umami flavor of food, as naturally occurring glutamate does in foods such as stews and meat soups.
Monosodium glutamate was first extracted in 1908 by Japanese biochemist Kikunae Ikeda, who tried to isolate and duplicate the savory taste of kombu, an edible seaweed used as a broth (dashi) ingredient in Japanese cuisine.
CAS: 142-47-2
MF: C5H10NNaO4
MW: 171.13
EINECS: 205-538-1
Synonyms
L-Glutamic acid monosodium salt monohydrate,L-2-Aminopentanedioic acid, MSG, Sodium L-glutamate;L-(+)Sodium glutamat;L-Glutamic acid mono;MSG (MONOSODIUM GLUTAMATE);L-SodiuM glutaMate hydrate;sodiumglutamatemonohydrate;vetsin;zest
Monosodium glutamate also balances, blends, and rounds the perception of other tastes.
Monosodium glutamate, along with disodium ribonucleotides, is commonly used and found in stock (bouillon) cubes, soups, ramen, gravy, stews, condiments, savory snacks, etc.
An optically active form of Monosodium glutamate having L-configuration.
The U.S. Food and Drug Administration has given MSG its generally recognized as safe (GRAS) designation.
Monosodium glutamate is a popular misconception that MSG can cause headaches and other feelings of discomfort, known as "Chinese restaurant syndrome".
Several blinded studies show no such effects when Monosodium glutamate is combined with food in normal concentrations, and are inconclusive when MSG is added to broth in large concentrations.
The European Union classifies Monosodium glutamate as a food additive permitted in certain foods and subject to quantitative limits.
Monosodium glutamate has the HS code 2922.42 and the E number E621.
Monosodium glutamate has a unique taste, known as “umami”, which is different from the four basic tastes of sweet, salty, sour, and bitter.
Monosodium glutamate is used in large quantities as a flavor enhancer throughout the world.
Monosodium glutamate is not a direct taste enhancer but a complex flavor enhancer for gravies, meats, poultry, sauces, and in other combinations.
Monosodium glutamate is also used to enhance the taste of tobacco and to treat hepatic coma.
As a salt of amino acid, Monosodium glutamate is also safe in practices of use and concentration in cosmetics, such as skin care products.
The best known and most widely used flavor enhancer is Monosodium glutamate.
In 1866, a German chemist, Ritthausen, isolated glutamic acid.
Later, another chemist converted the acid to a sodium salt, Monosodium glutamate.
In doing their work, neither had any interest in flavor.
More than 40 years later, in 1908, a Japanese chemist at the University of Tokyo, Dr. Kikunae Ikeda, discovered the flavor enhancing properties of MSG.
Dr. Ikeda had set out to find out why and how a certain seaweed, Laminaria japonica, affected flavor.
Japanese cooks had used this seaweed for centuries to improve the flavor of soups and certain other foods.
Dr. Ikeda discovered that the ingredient in the seaweed that made the difference was MSG, and that Monosodium glutamate had an unusual ability to enhance or intensify the flavor of many high protein foods.
After isolating MSG, Dr. Ikeda developed a process for extracting it from wheat flour and other flours.
Working with the Japanese chemical company, Suzuki and Co., he supervised the construction of a plant and, as a partner with the company, began commercial production of MSG in 1909.
There were several attempts to produce Monosodium glutamate in the United States in the years following, but it was not until the 1940s that large- scale Monosodium glutamate production began in this country. By 1968, U.S. production had grown to 46 million pounds per year.
The latest production figures (1987) reported 18.6 million pounds per year.
Flavor and enhancing properties.
At one time, it was felt that Monosodium glutamate had a somewhat meaty flavor and that this flavor was a factor in its ability to intensify the flavors of other foods, particularly protein-rich foods.
Monosodium glutamate was discovered, however, that the meaty taste came rather from contaminants in the crude glutamate, and when these contaminants were sharply reduced, the flavor characteristic also was reduced considerably.
MSG is not flavorless.
In large enough concentrations, or by itself, Monosodium glutamate has been found to have a taste of its own, sometimes described as sweet-saline.
There are some, in fact, who feel that Monosodium glutamate is nothing more than a seasoner which gains its effect by combining with and intensifying the flavors of the foods to which it is added.
However, to say that Monosodium glutamate only intensifies the flavor of foods is too simplistic.
When monosodium glutamate is added to food, several specific flavor characteristics are enhanced - such as impact, body or fullness, continuity, mouth fullness, mildness, and complexity.
Glutamate also harmonizes the wide range of flavors present in sauces, soups and casseroles, promoting a highly blended and full-bodied perception of flavor.
The savory taste of glutamate is to tomatoes, cheese, and meat what sweetness is to sugar, sourness is to lemons, saltiness is to anchovies and bitterness is to coffee.
Just as each of these foods has a distinctive taste, food high in glutamate has a basic and independent taste.
In China and Japan, there is a concept for this independent taste, which they call Xian-Wei (China) and Umami (Japan).
Current research has found more than 40 umami substances of which glutamate is most common.
In fact, umami is an integral part of cuisines throughout the world and has been described by Westerners as “savory,” “broth-like” and “meaty.”.
Production.
Monosodium glutamate is commonly produced using a fermentation process using a glucose (often sugar molasses) as a starting substance.
Once the glucose is converted to glutamic acid, the glutamic acid is filtered, dissolved and converted to monosodium glutamate by neutralization with sodium hydroxide.
The monosodium glutamate solution is decolorized.
Monosodium glutamate is then crystallized, dried, sieved, packed and shipped.
L-Glutamic acid, monosodium salt, commonly known as monosodium glutamate (MSG), is a sodium salt of the amino acid L-glutamic acid.
Monosodium glutamate is a white crystalline powder that is highly water-soluble and imparts a savory umami flavor, making it a popular flavor enhancer in foods.
Monosodium glutamate is notable for its ability to enhance the flavor of various dishes without adding significant calories.
Chemically, Monosodium glutamate contains a carboxyl group and an amino group, making it an amino acid derivative.
Monosodium glutamate is generally recognized as safe (GRAS) by food safety authorities when consumed in typical dietary amounts.
However, some individuals may experience sensitivity to Monosodium glutamate, leading to symptoms often referred to as "Chinese restaurant syndrome."
In addition to its culinary uses, Monosodium glutamate is also used in the food industry for its preservative properties and is involved in various biochemical processes in the body, including neurotransmission.
Overall, Monosodium glutamate is a versatile compound with significant applications in both food science and biochemistry.
Monosodium glutamate Chemical Properties
Melting point: 232°C
alpha: 20 -3.5° (10% soln in 5° Bé HCl); D20 +25.16° (10g MSG/100ml 2N HCl)
density: d20 (saturated water soln): 1.620
refractive index: 25 ° (C=10, 2mol/L HCl)
FEMA: 2756 | MONOSODIUM GLUTAMATE
storage temp.: Keep in dark place,Inert atmosphere,Room temperature
solubility: Soluble in water; sparingly soluble in ethanol (95%).
form: powder
color: white to off-white
Odor: Odorless
biological source: synthetic
Water Solubility: >=10 g/100 mL at 20 ºC
Merck: 6254
Stability: Hygroscopic
Cosmetics Ingredients Functions: FRAGRANCE
SKIN CONDITIONING
HAIR CONDITIONING
InChI: 1S/C5H9NO4.Na/c6-3(5(9)10)1-2-4(7)8;/h3H,1-2,6H2,(H,7,8)(H,9,10);/q;+1/p-1/t3-;/m0./s1
InChIKey: LPUQAYUQRXPFSQ-DFWYDOINSA-M
LogP: -1.44
CAS DataBase Reference: 142-47-2(CAS DataBase Reference)
EPA Substance Registry System: Monosodium glutamate (142-47-2)
Chemical properties
Monosodium glutamate is usually available as the monohydrate, a white, odorless, crystalline powder.
The solid contains separate sodium cations Na+ and glutamate anions in zwitterionic form, −OOC-CH(NH+3)-(CH2)2-COO−.
In solution, Monosodium glutamate dissociates into glutamate and sodium ions.
Monosodium glutamate is freely soluble in water, but it is not hygroscopic and is insoluble in common organic solvents (such as ether).
Monosodium glutamate is generally stable under food-processing conditions.
Monosodium glutamate does not break down during cooking and, like other amino acids, will exhibit a Maillard reaction (browning) in the presence of sugars at very high temperatures.
Monosodium glutamate, the best-known and most widely used flavor enhancer, is practically odorless and may have either a slightly sweet or slightly salty taste.
Addition of monosodium glutamate to food enhances several specific flavor characteristics, such as impact, body of fullness, continuity, mouth fullness, mildness and complexity.
For a detailed description of this compound refer to Burdock (1997)
Monosodium glutamate occurs as white free-flowing crystals or a crystalline powder.
Monosodium glutamate is practically odorless and has a meat-like taste.
sodium glutamate is an amino acid with skin-conditioning, odormasking, and hair-conditioning action.
Flavor enhancer for foods in concentration of about 0.3%.
Use
Pure Monosodium glutamate is reported to have a highly unpleasant taste until it is combined with a savory aroma.
The basic sensory function of MSG is attributed to its ability to enhance savory taste-active compounds when added in the proper concentration.
The optimal concentration varies by food; in clear soup, the "pleasure score" rapidly falls with the addition of more than one gram of MSG per 100 mL.
The sodium content (in mass percent) of MSG, 12.28%, is about one-third of that in sodium chloride (39.34%), due to the greater mass of the glutamate counterion, and the remainder, 87.72%, is glutamic acid.
Although other salts of glutamate have been used in low-salt soups, they are less palatable than MSG.
The ribonucleotide food additives disodium inosinate (E631) and disodium guanylate (E627), as well as conventional salt, are usually used with monosodium glutamate-containing ingredients as they seem to have a synergistic effect.
"Super salt" is a mixture of 9 parts salt, to one part MSG and 0.1 parts disodium ribonucleotides (a mixture of disodium inosinate and disodium guanylate).
Pharmaceutical Applications
Monosodium glutamate is used in oral pharmaceutical formulations as a buffer and a flavor enhancer.
For example, Monosodium glutamate is used with sugar to improve the palatability of bitter-tasting drugs and can reduce the metallic taste of iron-containing liquids.
Monosodium glutamate has also been used in subcutaneous live vaccine injections such as measles, mumps, rubella and varicella-zoster live vaccine (ProQuad).
However, the most widespread use of monosodium glutamate is as a flavor enhancer in food products.
Typically, 0.2–0.9% is used in normally salted foods, although products such as soy protein can contain 10–30%.
The use of monosodium glutamate in food products has been controversial owing to the apparently high number of adverse reactions attributed to the substance, which gives rise to the so-called ‘Chinese Restaurant Syndrome’.
The current consensus is that there is no clinically compelling evidence to suggest that monosodium glutamate may be harmful at the current levels used in foods.
Production
Monosodium glutamate has been produced by three methods: hydrolysis of vegetable proteins with hydrochloric acid to disrupt peptide bonds (1909–1962); direct chemical synthesis with acrylonitrile (1962–1973), and bacterial fermentation (the current method).
Wheat gluten was originally used for hydrolysis because Monosodium glutamate contains more than 30 g of glutamate and glutamine per 100 g of protein.
As demand for MSG increased, chemical synthesis and fermentation were studied.
The polyacrylic fiber industry began in Japan during the mid-1950s, and acrylonitrile was adopted as a base material to synthesize MSG.
As of 2016, most Monosodium glutamate worldwide is produced by bacterial fermentation in a process similar to making vinegar or yogurt.
Sodium is added later, for neutralization.
During fermentation, Corynebacterium species, cultured with ammonia and carbohydrates from sugar beets, sugarcane, tapioca or molasses, excrete amino acids into a culture broth from which L-glutamate is isolated.
Kyowa Hakko Kogyo (currently Kyowa Kirin) developed industrial fermentation to produce L-glutamate.
The conversion yield and production rate (from sugars to glutamate) continues to improve in the industrial production of Monosodium glutamate, keeping up with demand.
The product, after filtration, concentration, acidification, and crystallization, is glutamate, sodium ions, and water.
Preparation
Monosodium glutamate is commonly produced by a fermentation process using glucose (often sugar molasses) as a starting substance.
Once the glucose is converted to glutamic acid, it is filtered, dissolved and converted to monosodium glutamate by neutralization with sodium hydroxide.
The monosodium glutamate solution is decolorized and then crystallized, dried, sieved, packed and shipped.
Production Methods
Monosodium glutamate is the monosodium salt of the naturally occurring L-form of glutamic acid.
Monosodium glutamate is commonly manufactured by fermentation of carbohydrate sources such as sugar beet molasses.
In general, sugar beet products are used in Europe and the USA.
M 452 Monosodium Glutamate Other carbohydrate sources such as sugar cane and tapioca are used in Asia.
Synthesis
The industrial production of glutamic acid is primarily carried out in the form of monosodium glutamate (MSG), mainly through microbial fermentation.
This process has replaced earlier methods such as protein hydrolysis and chemical synthesis.
In this modern and efficient production method, specific bacterial strains, such as Corynebacterium glutamicum, are cultivated in large fermenters using carbohydrates such as sugarcane, sugar beets, or molasses as raw materials.
These bacteria secrete glutamic acid into the culture medium.
After fermentation, the glutamic acid is separated, purified, and then neutralized with sodium hydroxide, ultimately yielding the product—monosodium glutamate (MSG).
