![Monosodium glutamate crystals](https://upload.wikimedia.org/wikipedia/commons/8/89/Monosodium_glutamate_crystals.jpg)
Glutamate flavoring is the generic name for
flavor-enhancing compounds based on
glutamic acid
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synt ...
and its
salts
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively cha ...
(glutamates). These compounds provide an
umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats.
People taste umami through taste receptors that typically respond to glutamates and ...
(savory) taste to food.
Glutamic acid and glutamates are natural constituents of many
fermented
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
or aged foods, including
soy sauce
Soy sauce (also called simply soy in American English and soya sauce in British English) is a liquid condiment of Chinese origin, traditionally made from a fermented paste of soybeans, roasted grain, brine, and '' Aspergillus oryzae'' or ''Asp ...
,
fermented bean paste
Fermented bean paste is a category of fermented foods typically made from ground soybeans, which are indigenous to the cuisines of East, South and Southeast Asia. In some cases, such as the production of ''miso'', other varieties of beans, such ...
, and
cheese
Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...
. They can also be found in
hydrolyzed protein
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides. While many means of achieving this exist, most common is prolonged heating with hydrochloric acid, sometimes with an enzyme su ...
s such as
yeast extract
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...
. The
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
salt of glutamic acid,
monosodium glutamate
Monosodium glutamate (MSG), also known as sodium glutamate, is the sodium salt of glutamic acid. MSG is found naturally in some foods including tomatoes and cheese in this glutamic acid form. MSG is used in cooking as a flavor enhancer wit ...
(MSG), is manufactured on a large scale and widely used in the
food industry
The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditiona ...
.
Glutamic acid versus glutamates
When glutamic acid or any of its salts are dissolved in water, they form a
solution
Solution may refer to:
* Solution (chemistry), a mixture where one substance is dissolved in another
* Solution (equation), in mathematics
** Numerical solution, in numerical analysis, approximate solutions within specified error bounds
* Soluti ...
of separate
negative ions
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
, called
glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...
s, and positive ions like
or
. The result is actually a
chemical equilibrium
In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the sy ...
among several ionized forms, including
zwitterion
In chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion, is a molecule that contains an equal number of positively- and negatively-charged functional groups.
: With amino acids, for example, in solution a chemical equilibrium wil ...
s, that depends on the
pH (acidity) of the solution. Within the common pH range of foods, the prevailing ion can be described as
−OOC-C()-()
2-COO
−, which has an
electric charge
Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respe ...
of −1.
Only the glutamate ion is responsible for the umami flavor, so the effect does not depend significantly on the starting compound. However, some crystalline salts such as monosodium glutamate dissolve much better and faster than crystalline glutamic acid. This has proven to be an important factor in the implementation of substances as flavor enhancers.
Discovery
Although they occur naturally in many foods, glutamic acid and other amino acid flavor contributions were not scientifically identified until early in the twentieth century. In 1866, the German chemist
Karl Heinrich Ritthausen
Karl Heinrich Ritthausen (13 January 1826 – 16 October 1912) was a German biochemist who identified two amino acids and made other contributions to the science of plant proteins.
Education
Ritthausen was born in Armenruh, near Goldburg, Sil ...
discovered and identified the compound. In 1907, Japanese researcher
Kikunae Ikeda
was a Japanese chemist and Tokyo Imperial University professor of chemistry who, in 1908, uncovered the chemical basis of a taste he named umami. It is one of the five basic tastes along with sweet, bitter, sour and salty.
Ikeda graduated in 1 ...
of the
Tokyo Imperial University
, abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...
identified brown crystals left behind after the evaporation of a large amount of
kombu
''Konbu'' (from ja, 昆布, konbu or kombu) is edible kelp mostly from the family Laminariaceae and is widely eaten in East Asia. It may also be referred to as ''dasima'' ( ko, 다시마) or ''haidai'' ().
Kelp features in the diets of many c ...
broth as glutamic acid. These crystals, when tasted, reproduced the ineffable but undeniable flavor detected in many foods, especially seaweed. Professor Ikeda coined the term
umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats.
People taste umami through taste receptors that typically respond to glutamates and ...
for this flavor. He then patented a method of mass-producing the crystalline salt of glutamic acid known as monosodium glutamate.
Isomers
Further research into the compound has found that only the
L-glutamate
enantiomer
In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...
has flavor-enhancing properties.
Manufactured monosodium glutamate consists to over 99.6% of the naturally predominant L-glutamate form, which is a higher proportion of
L-glutamate than can be found in the free glutamate ions of fermented naturally occurring foods. Fermented products such as
soy sauce
Soy sauce (also called simply soy in American English and soya sauce in British English) is a liquid condiment of Chinese origin, traditionally made from a fermented paste of soybeans, roasted grain, brine, and '' Aspergillus oryzae'' or ''Asp ...
,
steak sauce
Steak sauce is a tangy sauce commonly served as a condiment for beef in the United States. Two of its major producers are British companies, and the sauce is similar to the "brown sauce" of British cuisine.
Overview
Steak sauce is normally br ...
, and
Worcestershire sauce have levels of glutamate similar to those in foods with added monosodium glutamate. However, 5% or more of the glutamate may be the
D-enantiomer. Nonfermented naturally occurring foods have lower relative levels of
D-glutamate than fermented products do.
Taste perception
Glutamic acid stimulates specific receptors located in
taste bud
Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...
s such as the
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
receptor
T1R1/
T1R3
Taste receptor type 1 member 3 is a protein that in humans is encoded by the ''TAS1R3'' gene. The ''TAS1R3'' gene encodes the human homolog of mouse Sac taste receptor, a major determinant of differences between sweet-sensitive and -insensitive mo ...
or other
glutamate receptor
Glutamate receptors are synaptic and non synaptic receptors located primarily on the membranes of neuronal and glial cells. Glutamate (the conjugate base of glutamic acid) is abundant in the human body, but particularly in the nervous system a ...
s like the metabotropic receptors (
mGluR4
Metabotropic glutamate receptor 4 is a protein that in humans is encoded by the ''GRM4'' gene.
Together with GRM6, GRM7 and GRM8 it belongs to Metabotropic glutamate receptor#Group II & Group III, group III of the metabotropic glutamate receptor ...
and
mGluR1
The glutamate receptor, metabotropic 1, also known as GRM1, is a human gene which encodes the metabotropic glutamate receptor 1 (mGluR1) protein.
Function
L-glutamate is the major excitatory neurotransmitter in the central nervous system and ...
), which induce the flavor known as
umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats.
People taste umami through taste receptors that typically respond to glutamates and ...
. This is classified as one of the five
basic tastes
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...
(the word "umami" is a
loanword
A loanword (also loan word or loan-word) is a word at least partly assimilated from one language (the donor language) into another language. This is in contrast to cognates, which are words in two or more languages that are similar because th ...
from
Japanese
Japanese may refer to:
* Something from or related to Japan, an island country in East Asia
* Japanese language, spoken mainly in Japan
* Japanese people, the ethnic group that identifies with Japan through ancestry or culture
** Japanese diaspor ...
; it is also referred to as "savory" or "meaty").
![IMP and GMP structure](https://upload.wikimedia.org/wikipedia/commons/b/bc/IMP_and_GMP_structure.jpg)
The flavoring effect of glutamate comes from its free form, in which it is not bound to other amino acids in protein. Nonetheless, glutamate by itself does not elicit an intense umami taste. The mixing of glutamate with
nucleotides
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules w ...
inosine-5'-monophosphate (IMP) or guanosine-5'-monophosphate (GMP) enhances the taste of umami; T1R1 and T1R3 respond primarily to mixtures of glutamate and nucleotides. While research has shown that this synergism occurs in some animal species with other amino acids, studies of human taste receptors show that the same reaction only occurs between glutamate and the selected nucleotides. Moreover, sodium in monosodium glutamate may activate glutamate to produce a stronger umami taste.
Two hypotheses for the explanation of umami taste transduction have been introduced: the first posits that the umami taste is transduced by an N-methyl-D-aspartate (NMDA) type glutamate ion channel receptor; the second posits that the taste is transduced by a metabotropic type glutamate receptor (taste-mGluR4). The metabotropic glutamate receptors such as mGluR4 and mGluR1 can be easily activated at glutamate concentration levels found in food.
Sources
Natural occurrence
Glutamate is ubiquitous in biological life. It is found naturally in all living cells, primarily in the bound form as a constituent of
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s. Only a fraction of the glutamate in foods is in its "free" form, and only free glutamate produces an
umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats.
People taste umami through taste receptors that typically respond to glutamates and ...
flavor in foods. The savory flavor of
tomato
The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word ...
es, fermented
soy
The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses.
Traditional unfermented food uses of soybeans include soy milk, from which tofu and ...
products,
yeast extract
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...
s, certain sharp cheeses, and fermented or
hydrolyzed protein
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides. While many means of achieving this exist, most common is prolonged heating with hydrochloric acid, sometimes with an enzyme su ...
products (such as soy sauce and
fermented bean paste
Fermented bean paste is a category of fermented foods typically made from ground soybeans, which are indigenous to the cuisines of East, South and Southeast Asia. In some cases, such as the production of ''miso'', other varieties of beans, such ...
) is partially due to the presence of free glutamate ions.
Asia
Japanese cuisine originally used
broth
Broth, also known as bouillon (), is a savory liquid made of water in which meat, fish or vegetables have been simmered for a short period of time. It can be eaten alone, but it is most commonly used to prepare other dishes, such as soups, ...
made from kombu (
kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms.
Kelp grows in "underwat ...
) to produce the umami taste in soups. Manufacturers, such as
Ajinomoto
is a Japanese multinational food and biotechnology corporation which produces seasonings, interlayer insulating materials for semiconductor packages for use in personal computers, cooking oils, frozen foods, beverages, sweeteners, amino acids, an ...
, use selected strains of ''
Corynebacterium glutamicum
''Corynebacterium glutamicum'' is a Gram-positive, rod-shaped bacterium that is used industrially for large-scale production of amino acids. While originally identified in a screen for organisms secreting L-glutamate, mutants of ''C. glutamicum' ...
''
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
in a nutrient-rich medium. The bacteria are selected for their ability to excrete glutamic acid, which is then separated from the nutrient medium and processed into its sodium salt, monosodium glutamate.
Rome
In the
Roman Empire
The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...
glutamic acid was found in a sauce called
garum
Garum is a fermented fish sauce that was used as a condiment in the cuisines of Phoenicia, ancient Greece, Rome, Carthage and later Byzantium. Liquamen is a similar preparation, and at times they were synonymous. Although garum enjoyed its grea ...
, made from fermenting fish in saltwater. The flavor enhancing properties of glutamic acid allowed Romans to reduce the use of expensive salt.
Concentration in foods
The following table illustrates the glutamate content of some selected common foods. Free glutamate is the form directly tasted and absorbed whereas glutamate bound in protein is not available until further breakdown by digestion or cooking. In general, vegetables contain more free glutamate but less protein-bound glutamate.
Hydrolyzed protein
Hydrolyzed protein
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides. While many means of achieving this exist, most common is prolonged heating with hydrochloric acid, sometimes with an enzyme su ...
s, or protein hydrolysates, are acid- or enzymatically treated proteins from certain foods. One example is
yeast extract
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...
. Hydrolyzed protein contains free amino acids, such as glutamate, at levels of 5% to 20%. Hydrolyzed protein is used in the same manner as monosodium glutamate in many foods, such as canned vegetables, soups, and processed meats.
Safety as a flavor enhancer
Studies
Monosodium glutamate (MSG) is regarded as safe for consumption. An association between MSG consumption and a constellation of symptoms has not been demonstrated under rigorously controlled conditions.
Techniques used to adequately control for experimental bias include a
placebo-controlled
Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed ...
double-blinded
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...
experimental design and the use of
capsules to deliver the compound to mask the strong and unique after-taste of glutamates.
Even though there are also reports of MSG sensitivity among a subset of the population, this has not been demonstrated in placebo‐controlled trials.
Chinese restaurant syndrome
Origin
The controversy surrounding the safety of MSG started on 4 April 1968, when Dr. Robert Ho Man Kwok wrote a correspondence letter to the ''
New England Journal of Medicine
''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one.
Hist ...
'', coining the term "Chinese restaurant syndrome".
In his letter, Kwok suggested several possible causes before he nominated MSG for his symptoms.
This letter was initially met with insider satirical responses, often using race as prop for humorous effect, within the medical community.
[ Some claimed that during the discursive uptake in media, the conversations were recontextualized as legitimate while the supposed race-based motivations of the humor were not parsed.][
In January 2018, Dr. Howard Steel claimed that it was actually a prank submission by him under a pseudonym.] However, it turned out that there was a Dr. Robert Ho Man Kwok who worked at the National Biomedical Research Foundation, both names Steel claimed to have invented. Kwok's children, his colleague at the research foundation, and the son of his boss there confirmed that Dr. Robert Ho Man Kwok, who had died in 2014, wrote this letter. After hearing about Kwok's family, Steel's daughter Anna came to believe that the admission that the letter was a prank was itself one of the last pranks by her late father.
The claims of 'Chinese restaurant syndrome' have the same symptoms as hypernatremia
Hypernatremia, also spelled hypernatraemia, is a high concentration of sodium in the blood. Early symptoms may include a strong feeling of thirst, weakness, nausea, and loss of appetite. Severe symptoms include confusion, muscle twitching, and b ...
, so it may actually be salt poisoning
Salt poisoning is an intoxication resulting from the excessive intake of sodium (usually as sodium chloride) in either solid form or in solution ( saline water, including brine, brackish water, eating salt, or seawater). Salt poisoning suffici ...
.
Reactions
Some authors and activists have attributed the negative perceptions around MSG to xenophobic or racist biases towards East Asians
East Asian people (East Asians) are the people from East Asia, which consists of China, Taiwan, Japan, Mongolia, North Korea, and South Korea. The total population of all countries within this region is estimated to be 1.677 billion and 21% of the ...
and East Asian cuisine
This is a list of Asian cuisines, by region. A cuisine is a characteristic style of cooking practices and traditions, usually associated with a specific culture or region. Asia, being the largest, most populous and culturally diverse continent, ...
, criticising the classification of alleged MSG-related symptoms as "Chinese Restaurant Syndrome".
In 2020, Ajinomoto
is a Japanese multinational food and biotechnology corporation which produces seasonings, interlayer insulating materials for semiconductor packages for use in personal computers, cooking oils, frozen foods, beverages, sweeteners, amino acids, an ...
, the leading manufacturer of MSG, launched the #RedefineCRS campaign to combat what it said was the myth that MSG is harmful to people's health. Following the #RedefineCRS campaign, Merriam-Webster announced it will be "reviewing" the term, which was added to the dictionary in 1993.
Regulations
Regulation timeline
In 1959, the U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) classified monosodium glutamate as generally recognized as safe (GRAS). This action stemmed from the 1958 Food Additives Amendment to the Federal Food, Drug, and Cosmetic Act
The United States Federal Food, Drug, and Cosmetic Act (abbreviated as FFDCA, FDCA, or FD&C) is a set of laws passed by the United States Congress in 1938 giving authority to the U.S. Food and Drug Administration (FDA) to oversee the safety of f ...
that required premarket approval for new food additives and led the FDA to promulgate regulations listing substances, such as monosodium glutamate, which have a history of safe use or are otherwise GRAS.
Since 1970, FDA has sponsored extensive reviews on the safety of monosodium glutamate, other glutamates, and hydrolyzed proteins, as part of an ongoing review of safety data on GRAS substances used in processed foods. One such review was by the Federation of American Societies for Experimental Biology
The Federation of American Societies for Experimental Biology (FASEB) is a non-profit organization that is the principal umbrella organization of U.S. societies in the field of biological and medical research. This organization organizes academi ...
(FASEB) Select Committee on GRAS Substances. In 1980, the committee concluded that monosodium glutamate was safe at current levels of use but recommended additional evaluation to determine monosodium glutamate's safety at significantly higher levels of consumption. Additional reports attempted to look at this.
In 1986, FDA's Advisory Committee on Hypersensitivity
Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune s ...
to Food Constituents concluded that monosodium glutamate poses no threat to the general public but that reactions of brief duration might occur in some people. Other reports have given the following findings:
* The 1987 Joint Expert Committee on Food Additives of the United Nations Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
and the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
placed monosodium glutamate in the safest category of food ingredients.
* A 1991 report by the European Community's (EC) Scientific Committee for Foods reaffirmed monosodium glutamate's safety and classified its "acceptable daily intake" as "not specified", the most favorable designation for a food ingredient. In addition, the EC Committee said, "Infants, including prematures, have been shown to metabolize glutamate as efficiently as adults and therefore do not display any special susceptibility to elevated oral intakes of glutamate." Legislation in effect since June 2013 classifies glutamic acid and glutamates as salt substitutes, seasonings, and condiments with a maximum level of consumption of 10g/kg expressed as glutamic acid.
European Union
Following the compulsory EU-food labeling law the use of glutamic acid and its salts has to be declared, and the name or E number
E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...
of the salt has to be listed. Glutamic acid and its salts as food additives have the following E numbers: glutamic acid
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synt ...
: E620, monosodium glutamate
Monosodium glutamate (MSG), also known as sodium glutamate, is the sodium salt of glutamic acid. MSG is found naturally in some foods including tomatoes and cheese in this glutamic acid form. MSG is used in cooking as a flavor enhancer wit ...
: E621, monopotassium glutamate
Monopotassium glutamate (MPG) is the compound with formula KC5H8NO4. It is a potassium salt of glutamic acid.
It has the E number E622 and is used in foods as a flavor enhancer. It is a non-sodium MSG
Monosodium glutamate (MSG), also known ...
: E622, calcium diglutamate
Calcium diglutamate, sometimes abbreviated CDG and also called calcium glutamate, is a compound with formula Ca(C5H8NO4)2. It is a calcium acid salt of glutamic acid. CDG is a flavor enhancer ( E number E623)—it is the calcium analog of mon ...
: E623, monoammonium glutamate
Monoammonium glutamate is a compound with formula NH4C5H8NO4. It is an ammonium acid salt of glutamic acid.
It has the E number E624 and is used as a flavor enhancer.
See also
* Monopotassium glutamate
Monopotassium glutamate (MPG) is the ...
: E624, and magnesium diglutamate: E625. In the European Union, these substances are regarded as "flavor enhancers" and are not allowed to be added to milk, emulsified fat and oil, pasta, cocoa/chocolate products and fruit juice. The EU has not yet published an official NOAEL The no-observed-adverse-effect level (NOAEL) denotes the level of exposure of an organism, found by experiment or observation, at which there is no biologically or statistically significant increase in the frequency or severity of any adverse effec ...
(no observable adverse effect level) for glutamate, but a 2006 consensus statement of a group of German experts drawing from animal studies was that a daily intake of glutamic acid of 6 grams per kilogram of body weight (6 g/kg/day) is safe. From human studies, the experts noted that doses as high as 147g/day produced no adverse effects in males when given for 30 days; in a male, this amount corresponds to 2.1 g per kg of body weight.
United States
In 1959, the Food and Drug Administration classified MSG as a "generally recognized as safe" ( GRAS) food ingredient under the Federal Food, Drug, and Cosmetic Act
The United States Federal Food, Drug, and Cosmetic Act (abbreviated as FFDCA, FDCA, or FD&C) is a set of laws passed by the United States Congress in 1938 giving authority to the U.S. Food and Drug Administration (FDA) to oversee the safety of f ...
. In 1986, FDA's Advisory Committee on Hypersensitivity to Food Constituents also found that MSG was generally safe, but that short-term reactions may occur in some people. To further investigate this matter, in 1992 the FDA contracted the Federation of American Societies for Experimental Biology
The Federation of American Societies for Experimental Biology (FASEB) is a non-profit organization that is the principal umbrella organization of U.S. societies in the field of biological and medical research. This organization organizes academi ...
(FASEB) to produce a detailed report, which was published in 1995. The FASEB report reaffirmed the safety of MSG when it is consumed at usual levels by the general population, and found no evidence of any connection between MSG and any serious long-term reactions.[
Under 2003 ]U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
regulations, when monosodium glutamate is added to a food, it must be identified as "monosodium glutamate" in the label's ingredient list. Because glutamate is commonly found in food, primarily from protein sources, the FDA does not require foods and ingredients that contain glutamate as an inherent component to list it on the label. Examples include tomatoes, cheeses, meats, hydrolyzed protein
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides. While many means of achieving this exist, most common is prolonged heating with hydrochloric acid, sometimes with an enzyme su ...
products such as soy sauce, and autolyzed yeast
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture Growing media, media. They are often used to create savory flavors and umami taste ...
extracts. These ingredients are to be declared on the label by their common or usual names. The term 'natural flavor' is now used by the food industry when using glutamic acid. Because of lack of regulation, it is impossible to determine what percentage of 'natural flavor' is actually glutamic acid.
The food additives disodium inosinate
Disodium inosinate (E631) is the disodium salt of inosinic acid with the chemical formula C10H11N4Na2O8P. It is used as a food additive and often found in instant noodles, potato chips, and a variety of other snacks. Although it can be obtaine ...
and disodium guanylate
Disodium guanylate, also known as sodium 5'-guanylate and disodium 5'-guanylate, is a natural sodium salt of the flavor enhancing nucleotide guanosine monophosphate (GMP). Disodium guanylate is a food additive with the E number E627. It is commo ...
are usually used in synergy with monosodium glutamate-containing ingredients, and provide a likely indicator of the addition of glutamate to a product.
As of 2002 the National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
Committee on Dietary Reference Intakes had not set a NOAEL The no-observed-adverse-effect level (NOAEL) denotes the level of exposure of an organism, found by experiment or observation, at which there is no biologically or statistically significant increase in the frequency or severity of any adverse effec ...
or LOAEL for glutamate.[
]
Australia and New Zealand
Standard 1.2.4 of the Australia New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
Food Standards Code requires the presence of monosodium glutamate as a food additive to be labeled. The label must bear the food additive class name (such as "flavor enhancer"), followed by either the name of the food additive (such as "MSG") or its International Numbering System
The International Numbering System for Food Additives (INS) is a European-based naming system for food additives, aimed at providing a short designation of what may be a lengthy actual name."Class Names and the International Numbering System for F ...
(INS) number (e.g., "621").
Canada
The Canada Food Inspection Agency considers claims of "no MSG" or "MSG free" to be misleading and deceptive when other sources of free glutamates are present.
Ingredients
Forms of glutamic acid that can be added to food include:
* Monosodium glutamate
Monosodium glutamate (MSG), also known as sodium glutamate, is the sodium salt of glutamic acid. MSG is found naturally in some foods including tomatoes and cheese in this glutamic acid form. MSG is used in cooking as a flavor enhancer wit ...
* Glutamic acid
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synt ...
(E620), glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...
(E620)
* Monopotassium glutamate
Monopotassium glutamate (MPG) is the compound with formula KC5H8NO4. It is a potassium salt of glutamic acid.
It has the E number E622 and is used in foods as a flavor enhancer. It is a non-sodium MSG
Monosodium glutamate (MSG), also known ...
(E622)
* Calcium glutamate (E623)
* Monoammonium glutamate
Monoammonium glutamate is a compound with formula NH4C5H8NO4. It is an ammonium acid salt of glutamic acid.
It has the E number E624 and is used as a flavor enhancer.
See also
* Monopotassium glutamate
Monopotassium glutamate (MPG) is the ...
(E624)
* Magnesium glutamate
Magnesium diglutamate is a compound with formula Mg(C5H8NO4)2. It is a magnesium acid salt of glutamic acid.
It has the E number E625 and is used in foods as a flavor enhancer
A flavoring (or flavouring), also known as flavor (or flavour) o ...
(E625)
* Sodium glutamate (E621)
The following are also rich sources of glutamic acid, and may be added for umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats.
People taste umami through taste receptors that typically respond to glutamates and ...
flavor:
* Hydrolyzed vegetable protein
Hydrolyzed vegetable protein (HVP) products are foodstuffs obtained by protein hydrolysis and are used as ingredients to create a bouillon (broth) taste without the vegetables, bones, simmering, or other standard elements of creating bouillon fr ...
* Autolyzed yeast
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture Growing media, media. They are often used to create savory flavors and umami taste ...
, yeast extract
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...
, yeast food, and nutritional yeast
Nutritional yeast (also known as nooch) is a deactivated yeast, often a strain of ''Saccharomyces cerevisiae'', that is sold commercially as a food product. It is sold in the form of yellow flakes, granules, or powder and can be found in the bul ...
* Cheese
Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...
products, e.g. parmesan
Parmesan ( it, Parmigiano Reggiano; ) is an Italian hard, granular cheese produced from cows’ milk and aged at least 12 months.
It is named after two of the areas which produce it, the provinces of Parma and Reggio Emilia (''Parmigiano'' is ...
(1200 mg / 100 g)
* Various savory fermented seasonings, including soy sauce
Soy sauce (also called simply soy in American English and soya sauce in British English) is a liquid condiment of Chinese origin, traditionally made from a fermented paste of soybeans, roasted grain, brine, and '' Aspergillus oryzae'' or ''Asp ...
and worcestershire sauce
* (See for more examples.)
See also
Notes
References
* Jordan Sand Jordan Sand is an American Japanologist. He is a professor of Japanese history and culture at Georgetown University with a focus on the architectural and cultural history of Japan.
Biography
Sand received his B.A. and Ph.D. from Columbia Universi ...
, "A Short History of MSG: Good Science, Bad Science, and Taste Cultures", ''Gastronomica '5:4 (Fall 2005). History of MSG and its marketing in Japan, Taiwan (under the Japanese), China, and the U.S.
* ''Federal Register'', Dec. 4, 1992 (FR 57467)
* ''Federal Register'', Jan. 6, 1993 (FR 2950)
* FDA Consumer, December 1993, "Food Allergies: When Eating is Risky".
External links
* See the segments "Prologue" and "Humor Is Not the Best Medicine" for the story behind "Chinese restaurant syndrome".
{{DEFAULTSORT:Glutamic Acid (Flavor)
Condiments
Flavor enhancers
Food additives
Glutamates
Umami enhancers