Monosodium glutamate
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[[WP:UNDO|Undid]] revision 226125315 by [[Special:Contributions/AudienceOfOne|AudienceOfOne]] ([[User talk:AudienceOfOne|talk]])
{{Otheruses4|the chemical compound|its use in food flavoring and health concerns|glutamic acid (flavor)|glutamic acid in general|glutamic acid}}
{{Chembox new
|ImageFile=MSG.png
|ImageSize=275px
|IUPACName=Sodium (2S)-2-amino-5-hydroxy-5-oxo-pentanoate
|OtherNames=
|Section1= {{Chembox Identifiers
| CASNo=142-47-2
| PubChem=85314
| SMILES=C(CC(=O)O)C(C(=O)[O-])N.[Na+]
}}
|Section2= {{Chembox Properties
| Formula=C<sub>5</sub>H<sub>8</sub>NNaO<sub>4</sub>
| MolarMass=169.111
| Appearance=white crystalline powder
| Density=
| MeltingPt=225℃
| BoilingPt=
| Solubility=very soluble in water
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}
[[Image:Monosodium glutamate crystals.jpg|thumb|right|300px|Crystalline MSG]]
'''Monosodium glutamate''', also known as '''sodium glutamate''' and '''MSG''', is a [[sodium salt]] of the non-essential [[amino acid]] [[glutamic acid]]. It is used as a [[food additive]] and is commonly marketed as a [[flavour enhancer]]. It has the [[Harmonized System Code|HS code]] 29224220 and the [[E number]] E621. Trade names of monosodium glutamate include ''Ajinomoto'', ''Vetsin'', and ''Accent''.
Although traditional Asian cuisine uses flavour-enhancing ingredients which contain high concentrations of MSG, it was not isolated until 1907. MSG was subsequently patented by the Japanese [[Ajinomoto]] Corporation in 1909. In its pure form, it appears as a white crystalline powder; when dissolved in water (or saliva) it rapidly dissociates into [[sodium]] [[cation]]s and [[glutamate]] [[anion]]s (glutamate is the anionic form of glutamic acid, a naturally occurring amino acid).
==Production and chemical properties==
MSG is prepared by fermentation of carbohydrate sources (see below). Species of the genuses [[Brevibacterium]] and [[Corynebacterium]] are useful. Yields of 100 g/liter can be prepared in this way. From 1909 to the mid 1960s, MSG was prepared by hydrolysis of wheat gluten, which contains about 25% of glutamic acid. Glutamic acid is one of the least soluble amino acids, thus facilitating its purification.<ref>Tetsuya Kawakita, Chiaki Sano, Shigeru Shioya, Masahiro Takehara, Shizuko Yamaguchi, “Monosodium Glutamate” in Ullmann’s Encyclopedia of Industrial Chemistry 2005, Wiley-VCH , Weinheim. {{DOI|10.1002/14356007.a16 711}}.</ref>
Like the sodium salts of other amino acids, MSG is a stable colourless solid that is degraded by strong oxidizing agents. It exists as [[enantiomer]]s, but only the naturally occurring <small>L</small>-glutamate form is used as a flavour enhancer.
== Commercialization ==
The [[Ajinomoto]] company was formed to manufacture and market MSG in [[Japan]]; the name 'Ajinomoto' means "essence of taste". It was introduced to the United States in 1947 as ''Ac'cent flavor enhancer''.
Modern commercial MSG is produced by fermentation<ref>[http://www.ajinomoto.com/amino/eng/product.html http://www.ajinomoto.com/amino/eng/product.html]</ref> of [[starch]], [[sugar beet]]s, [[sugar cane]], or [[molasses]]. About 1.5 million [[Tonne|metric tons]] were sold in [[2001]], with 4% annual growth expected.<ref>[http://www.ajinomoto.co.jp/ajinomoto/A-Company/company/zaimu/pdf/fact/food_biz.pdf http://www.ajinomoto.co.jp/ajinomoto/A-Company/company/zaimu/pdf/fact/food_biz.pdf]</ref>
MSG is used commercially as a flavour enhancer. Although once stereotypically associated with foods in [[Chinese restaurant syndrome|Chinese restaurants]], it is now found in many common food items, particularly [[Food processing|processed foods]]. <ref>[http://www.nytimes.com/2008/03/05/dining/05glute.html?_r=1&oref=slogin ''NY Times'': Yes, MSG, the Secret Behind the Savor] - March 5, 2008.</ref> Examples include:
<!-- MSG is a flavor enhancer ie. a short cut in food production. Anything processed in a factory or home is likely to have MSG -->
* Canned soups.
* Pre-prepared [[Stock (food)|stocks]] often known as stock cubes.
* Condiments such as [[barbecue sauce]].
* Frozen dinners.
* Frozen seafood.
* Common [[snack food]]s such as flavored [[potato chips]] and flavored [[tortilla chips]].
* Most [[fast food]].
* Instant meals such as the seasoning mixtures for [[instant noodles]].
* The popular Hispanic food additive [[Sazón]].
Only the <small>L</small>-glutamate [[enantiomer]] has flavour-enhancing properties.<ref name="D-Glutamate">{{cite journal | author=Kimber L. Rundlett, Dr. Daniel W. Armstrong | title=Evaluation of free <small>D</small>-glutamate in processed foods | url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7915127&dopt=Abstract |journal=Chirality | year=1994 | volume=6 | issue=4 | pages= 277–282 | doi=10.1002/chir.530060410 }}</ref> Manufactured MSG contains over 99.6% of the naturally predominant L-glutamate form, which is a higher proportion of L-glutamate than found in the free glutamate ions of naturally occurring foods. Fermented products like [[soy sauce]], [[steak sauce]], and [[Worcestershire sauce]] have comparable levels of glutamate as foods with added MSG. However, glutamate in these brewed products may be composed 5% or more of the D-enantiomer.<ref name="D-Glutamate" />
== Health controversy ==
{{main|Glutamic acid (flavor)#Health concerns}}
Monosodium glutamate as a food ingredient is the subject of a health concern controversy.
=== United States ===
Under current [[Food and Drug Administration]] (FDA) regulations, when MSG is added to a food, it must be identified as "monosodium glutamate" in the label's ingredient list. If MSG is part of a spice mix that is purchased from another company, the manufacturer is still required to list the ingredients of that spice mix including MSG. Some companies whether intentionally or unknowingly may simply use the words "flavorings" or "spices" even if other ingredients including MSG are present. This is technically against the regulation and should the company be questioned about it, it would be required to update the labels.{{who}}
Also, MSG is only one of several forms of free glutamate used in foods. Free glutamate may also be present in a wide variety of other additives, including [[hydrolysis|hydrolyzed]] vegetable proteins, [[autolyzed yeast]], [[Yeast extract#Hydrolyzed yeast|hydrolyzed yeast]], [[yeast extract]], [[soybean|soy]] extracts, protein isolate, "spices" and "natural flavorings." The food additives [[disodium inosinate]] and [[disodium guanylate]] are useful only in synergy with MSG-containing ingredients, and provide a likely indicator of the presence of MSG in a product.
For this reason, FDA considers labels such as "No MSG" or "No Added MSG" to be misleading if the food contains ingredients that are sources of free glutamate, such as [[hydrolyzed protein]].<ref name="fda">U. S. Department of Health and Human Services, U. S. Food and Drug Administration, "[http://www.cfsan.fda.gov/~lrd/msg.html FDA and Monosodium Glutamate (MSG)]," August 31, 1995</ref>
In 1993, FDA proposed adding the phrase "(contains glutamate)" to the common or usual names of certain protein hydrolysates that contain substantial amounts of glutamate.<ref name="fda" /> For example, if the proposal were adopted, hydrolyzed [[soy protein]] would have to be declared on food labels as "hydrolyzed soy protein (contains glutamate)."
In 1994, FDA received a citizen's petition requesting changes in labeling requirements for foods that contain MSG or related substances.<ref name="fda" /> <!-- from who? --> The petition asks for mandatory listing of MSG as an ingredient on labels of manufactured and processed foods that contain manufactured free glutamic acid. It further asks that the amount of free glutamic acid or MSG in such products be stated on the label, along with a warning that MSG may be harmful to certain groups of people (in much the same way products with [[aspartame]] have a warning for [[phenylketonuric]]s). FDA has not yet taken action on the petition.<!-- how can you cite negative information? -->
=== Europe ===
MSG has the [[E number]] E621.
=== Asia ===
The INTERMAP Cooperative Research Group conducted a study of 752 healthy Chinese (48.7% women), aged 40-59 years, randomly sampled from three rural villages in north and south China and determined that MSG intake may be positively related to BMI ([[Body Mass Index]])<ref>
{{cite journal
|title=Association of monosodium glutamate intake with overweight in Chinese adults: The INTERMAP study.
|pmid=18497735
}}</ref>
=== Australia and New Zealand ===
Standard 1.2.4 of the Australia [[New Zealand]] Food Standards Code requires the presence of MSG as a food additive to be labeled. The label must bear the food additive class name (eg. flavour enhancer), followed by either the name of the food additive (eg MSG) or its International Numbering System (INS) number (eg 621).
== See also ==
* [[Ajinomoto|Ajinomoto Co., Inc.]]
* [[Umami]]
* [[Excitotoxicity]]
* [[Flavour enhancer]]
* [[Disodium glutamate]]
* [[List of food additives]]
* [[Yeast extract]]
== References ==
{{reflist}}
== External Links ==
*[http://www.fda.gov/FDAC/features/2003/103_msg.html FDA: No long-term hazard]
*[http://www.msgtruth.org msgtruth.org]
[[Category:Food additives]]
[[Category:Sodium compounds]]
[[Category:Flavour enhancers]]
[[Category:Umami enhancers]]
[[ar:غلوتامات أحادية الصوديوم]]
[[be:Глутамат натрыю]]
[[be-x-old:Глутамат натрыю]]
[[bg:Мононатриев глутамат]]
[[cs:Glutaman sodný]]
[[da:Mononatriumglutamat]]
[[de:Mononatriumglutamat]]
[[es:Glutamato monosódico]]
[[fr:Glutamate monosodique]]
[[ko:글루탐산 나트륨]]
[[id:Mononatrium glutamat]]
[[it:Glutammato monosodico]]
[[he:מונוסודיום גלוטמט]]
[[hu:Nátrium-glutamát]]
[[ml:അജിനോമോട്ടോ]]
[[mr:मोनोसोडियम ग्लुटामेट]]
[[ms:Monosodium glutamat]]
[[nl:Mononatriumglutamaat]]
[[ja:グルタミン酸ナトリウム]]
[[no:Natriumglutamat]]
[[pl:Glutaminian sodu]]
[[pt:Glutamato monossódico]]
[[ru:Глутамат натрия]]
[[sk:Glutaman sodný]]
[[fi:Natriumglutamaatti]]
[[sv:Natriumglutamat]]
[[th:ผงชูรส]]
[[vi:Glutamat natri]]
[[uk:Глютамат натрію]]
[[zh-yue:味精]]
[[zh:味精]]