Glutamate flavoring
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/89/Monosodium_glutamate_crystals.jpg/300px-Monosodium_glutamate_crystals.jpg)
Glutamate flavoring is the generic name for
Glutamic acid and glutamates are natural constituents of many
Glutamic acid versus glutamates
When glutamic acid or any of its salts are dissolved in water, they form a
3O+
or Na+
. The result is actually a chemical equilibrium among several ionized forms, including zwitterions, 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(NH+
3)-(CH
2)2-COO−, which has an electric charge
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
Isomers
Further research into the compound has found that only the L-glutamate enantiomer has flavor-enhancing properties.[3] 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, steak sauce, 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.[3]
Taste perception
Glutamic acid stimulates specific receptors located in
; it is also referred to as "savory" or "meaty").![](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3d/IMP_and_GMP.svg/220px-IMP_and_GMP.svg.png)
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
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).[7] The metabotropic glutamate receptors such as mGluR4 and mGluR1 can be easily activated at glutamate concentration levels found in food.[8]
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
Asia
Japanese cuisine originally used broth made from kombu (kelp) to produce the umami taste in soups.[11]
Rome
In the Roman Empire glutamic acid was found in a sauce called garum, made from fermenting fish in saltwater. The flavor enhancing properties of glutamic acid allowed Romans to reduce the use of expensive salt.[12][13]
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.[14][15]
Food | Free glutamate (mg/100 g) | Protein glutamate (mg/100 g) |
---|---|---|
Makombu (kelp) | 3190 | |
Rausu kombu (kelp) | 2286 | |
Rishiri kombu (kelp) | 1985 | |
Marmite | 1960[14] | |
Hidaka kombu (kelp) | 1344 | |
Nori (seaweed) | 1378 | |
Vegemite | 1431[14] | |
Japanese fish sauce | 1383 | |
Roquefort cheese |
1280 | |
Parmesan cheese |
1200 | 9847 |
Korean soy sauce | 1264 | |
Chinese soy sauce | 926 | |
Japanese soy sauce | 782 | |
Oyster sauce | 900 | |
Green Tea |
668 | |
Cured Ham | 337 | |
Sardine | 280 | |
Grape juice | 258 | |
Clam | 208 | |
Peas |
200 | 5583 |
Scallop | 159 | |
Squid | 146 | |
Tomatoes | 140 | 238 |
Oyster | 137 | |
Corn | 130 | 1765 |
Mussel | 105 | |
Potatoes | 102 | |
Duck | 69 | 3636 |
Chicken | 44 | 3309 |
Beef | 33 | 2846 |
Pork | 23 | 2325 |
Eggs |
23 | 1583 |
Human milk | 22 | 229 |
Salmon | 20 | 2216 |
Cow milk | 2 | 819 |
Hydrolyzed protein
Hydrolyzed proteins, or protein hydrolysates, are acid- or enzymatically treated proteins from certain foods. One example is yeast extract. 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.
Pure salts
Manufacturers, such as Ajinomoto, use selected strains of Corynebacterium glutamicum bacteria 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.[11]
Safety as a flavor enhancer
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Ajinomoto_msg.jpg/220px-Ajinomoto_msg.jpg)
Studies
Monosodium glutamate (MSG) is regarded as safe for consumption.
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
In January 2018, Dr. Howard Steel claimed that it was actually a prank submission by him under a pseudonym.[22][24] 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.[24] 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.[24] 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.[24]
The claims of "Chinese restaurant syndrome" have the same symptoms as hypernatremia, so it may actually be salt poisoning.[25]
Reactions
Some authors and activists
In 2020, Ajinomoto, 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.[35] Following the #RedefineCRS campaign, Merriam-Webster announced it will be "reviewing" the term,[36] which was added to the dictionary in 1993.[37][38]
Regulations
Regulation timeline
In 1959, the
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 (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.[citation needed]
In 1986, FDA's Advisory Committee on Hypersensitivity 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 and the World Health Organization placed monosodium glutamate in the safest category of food ingredients.
- A 1991 report by the 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[40] with a maximum level of consumption of 10g/kg expressed as glutamic acid.[41]
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
United States
In 1959, the Food and Drug Administration classified MSG as a "generally recognized as safe" (
Under 2003
The food additives disodium inosinate and disodium guanylate 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[update], the
Australia and New Zealand
Standard 1.2.4 of the Australia New Zealand 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 (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.[45]
Ingredients
Forms of glutamic acid that can be added to food include:
- Monosodium glutamate
- glutamate(E620)
- Monopotassium glutamate (E622)
- Calcium glutamate(E623)
- Monoammonium glutamate (E624)
- Magnesium glutamate(E625)
- Sodium glutamate(E621)
The following are also rich sources of glutamic acid, and may be added for umami flavor:[1]
- Hydrolyzed vegetable protein
- Autolyzed yeast, yeast extract, yeast food, and nutritional yeast
- Cheese products, e.g. parmesan (1200 mg / 100 g)
- Various savory fermented seasonings, including soy sauce and worcestershire sauce
- (See § Sources for more examples.)
See also
Notes
- ^ a b Renton, Alex (July 10, 2005). "If MSG is so bad for you, why doesn't everyone in Asia have a headache?". The Guardian. Retrieved November 21, 2008.
- ^ "Kikunae Ikeda Sodium Glutamate". Japan Patent Office. October 7, 2002. Archived from the original on October 28, 2007. Retrieved November 21, 2008.
- ^ PMID 7915127.
- PMID 10736351.
- PMID 23339178.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - PMID 10736357.
- S2CID 16650588.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ^ U.S. Food and Drug Administration (November 19, 2012). "Questions and Answers on Monosodium glutamate (MSG): How is it Made?". Food and Drug Administration. Retrieved March 9, 2017.
- ^ See column "Free glutamate" in the Concentration in foods subsection's table
- ^ ISBN 978-0-471-79930-6.
- ^ Rossella Lorenzi (September 29, 2008). "Fish Sauce Used to Date Pompeii Eruption". Discovery News.
- ^ K. Kris Hirst. "Roman Empire Fish Sauce Garum". Archived from the original on January 14, 2012. Retrieved December 3, 2010.
- ^ a b c "MONOSODIUM GLUTAMATE A Safety Assessment" (PDF). Food Standards Australia New Zealand. June 2003. Retrieved February 25, 2024.
- ^ "Umami Information Center". Archived from the original on February 2, 2012. Retrieved February 2, 2012.
- ^ "MSG in food". www.foodstandards.gov.au. Food Standards Australia New Zealand. October 2017. Archived from the original on September 23, 2020. Retrieved January 29, 2019.
- ^ "Questions and Answers on Monosodium glutamate (MSG)". www.fda.gov. U.S. Food and Drug Administration. November 19, 2012.
- ^ PMID 8282275.
- ^ S2CID 21084909.
- PMID 4936399.
- ^ .
- ^ a b Blanding, Michael (February 6, 2019). "The Strange Case of Dr. Ho Man Kwok". Colgate Magazine. Retrieved January 6, 2020.
- PMID 25276867.
- ^ a b c d Sullivan, Lilly (February 15, 2019). "668: The Long Fuse". This American Life. Retrieved January 7, 2020.
- PMID 5771078.
- ^ Jiang, Irene (January 15, 2020). "McDonald's is testing chicken sandwiches with MSG, and people are freaking out. Here's why they shouldn't care one bit". Business Insider.
- ^ Nierenberg, Amelia (January 16, 2020). "The Campaign to Redefine 'Chinese Restaurant Syndrome'". The New York Times.
- ^ Davis, River (April 27, 2019). "The FDA Says It's Safe, So Feel Free to Say 'Yes' to MSG". The Wall Street Journal.
- .
Introduction: 'Chinese Restaurant Syndrome' as Rhetorical [...] Finally, I trace how the journalistic uptakes of this discussion, in only taking up certain medical phrases and terms, reproduce the tacit racism of this boundary policing while avowing the neutrality of medical authority.
- ^ DeJesus, Erin (October 16, 2016). "Recapping Anthony Bourdain 'Parts Unknown' in Sichuan". Eater. Vox Media. See also "Bourdain, off the cuff: Sichuan". Explore Parts Unknown. CNN. March 28, 2018. Retrieved December 14, 2018.
[On MSG]: You know what causes Chinese-restaurant syndrome? Racism. 'Ooh, I have a headache, must have been the Chinese guy.'
- ^ Barry-Jester, Anna Maria (January 8, 2016). "How MSG Got A Bad Rap: Flawed Science And Xenophobia". FiveThirtyEight.
That MSG causes health problems may have thrived on racially charged biases from the outset. Ian Mosby, a food historian, wrote in a 2009 paper titled "'That Won-Ton Soup Headache': The Chinese Restaurant Syndrome, MSG and the Making of American Food, 1968-1980" that fear of MSG in Chinese food is part of the U.S.'s long history of viewing the "exotic" cuisine of Asia as dangerous or dirty.
- ^ "Why Do People Freak Out About MSG in Chinese Food?". AJ+. Al Jazeera Media Network. August 14, 2018 – via YouTube.
- ^ Blythman, Joanna (May 21, 2018). "Chinese restaurant syndrome: has MSG been unfairly demonised?". The Guardian.
Although Chang doesn't use MSG in his kitchens, he has defended its use, telling a high-level meeting of top chefs that Chinese restaurant syndrome is nothing more than a "cultural construct". That is a polite way of saying that avoidance of MSG is an expression of Western ignorance, or worse, racism, drawing on stereotypes of East Asian countries as dangerous or dirty.
- ^ Geiling, Natasha (November 8, 2013). "It's the Umami, Stupid. Why the Truth About MSG is So Easy to Swallow". Smithsonian.
Everyone knows this connection, and probably associates MSG use in America most heavily with Chinese restaurants – thanks in large part to the absurdly racist name for MSG sensitivity "Chinese Restaurant Syndrome."
- ^ Yeung, Jessie (January 19, 2020). "MSG in Chinese food isn't unhealthy -- you're just racist, activists say". CNN.
- ^ Theisen, Lauren (January 19, 2020). "Activists launch campaign to fight 'Chinese restaurant syndrome' myth". nydailynews.com. Archived from the original on January 20, 2020. Retrieved January 20, 2020.
- ^ "Food fight takes aim at dictionary entry". BBC. January 16, 2020. Retrieved January 20, 2020.
- ^ "Definition of CHINESE RESTAURANT SYNDROME". merriam-webster.com. Retrieved January 20, 2020.
- U.S. Food and Drug Administration. Archived from the originalon May 21, 2007. Retrieved March 22, 2008.
- ^ European Community. "Food Additives Database". DG Sanco, Bruxelles. Archived from the original on April 22, 2016. Retrieved January 18, 2013.
- ^ "COMMISSION REGULATION (EU) No 1129/2011". European Community.
- ^ PMID 16957679.
- ^ PMID 12625304.
- ISBN 978-0-309-08525-0. Retrieved February 16, 2012.
- ^ "4 – Composition, Quality, Quantity and Origin Claims Sections 4.1–4.6". Canadian Food Inspection Agency. Inspection.gc.ca. March 3, 2011. Archived from the original on July 14, 2017. Retrieved April 11, 2015.
References
- Jordan Sand, "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
- "The Long Fuse". This American Life (Radio broadcast). Episode 668. February 15, 2019. Public Radio Exchange (PRX). WBEZ. Retrieved February 21, 2019. See the segments "Prologue" and "Humor Is Not the Best Medicine" for the story behind "Chinese restaurant syndrome".