Monosodium glutamate

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This article is about the chemical compound. For its use in food, see glutamic acid (flavor). For glutamic acid in general, see glutamic acid.
For other uses, see MSG (disambiguation).
Monosodium glutamate
Chemical composition of monosodium glutamate
Structure of monosodium glutamate
Crystalline monosodium glutamate
Identifiers
CAS number 142-47-2 YesY
PubChem 85314
ChemSpider 76943 YesY
UNII C3C196L9FG YesY
EC-number 205-538-1
Jmol-3D images {{#if:Na+.O=C(O-)[C@@H](N)CCC(=O)O|Image 1
Properties
Molecular formula C5H8NO4Na
Molar mass 169.111 g/mol
Appearance White crystalline powder
Melting point 232 °C (450 °F; 505 K)
Solubility in water 74 g/100 mL
Hazards
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chloride Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 15800 mg/kg (oral, rat)[Gov. 1]
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Monosodium glutamate (MSG, also known as sodium glutamate) is the sodium salt of glutamic acid, one of the most abundant naturally-occurring non-essential amino acids.[Manuf. 1] MSG is found in tomatoes, Parmesan, potatoes, mushrooms, and other vegetables and fruits.[1]

MSG is used in the food industry as a flavor enhancer with an umami taste that intensifies the meaty, savory flavor of food, as naturally occurring glutamate does in foods such as stews and meat soups.[2] This was first prepared by Japanese biochemist Kikunae Ikeda, who was seeking to isolate and duplicate the savory taste of kombu, an edible seaweed used as a base for many Japanese soups. MSG as a flavor enhancer balances, blends and rounds the perception of other tastes.[3][4] It is particularly popular in Japanese and Chinese cuisine.

The U.S. Food and Drug Administration has given MSG its generally recognized as safe (GRAS) designation. While a popular belief holds that large doses of MSG can cause headaches and other feelings of discomfort, in controlled studies scientists have been unable to consistently trigger reactions.[Gov. 2] The European Union classifies it as a food additive permitted in certain foods and subject to quantitative limits. MSG has the HS code 29224220 and the E number E621.[Gov. 3]

Names and synonyms[edit]

The following are alternative names for MSG:[Gov. 1][Manuf. 2][Manuf. 3]

Chemical names and identifiers[edit]

  • Monosodium glutamate
  • Sodium 2-aminopentanedioate
  • Glutamic acid, monosodium salt, monohydrate
  • L-Glutamic acid, monosodium salt, monohydrate
  • L-Monosodium glutamate monohydrate
  • Monosodium L-glutamate monohydrate
  • MSG monohydrate
  • Sodium glutamate monohydrate
  • UNII-W81N5U6R6U

Trade names[edit]

History[edit]

Kikunae Ikeda of Tokyo Imperial University isolated glutamic acid as a taste substance in 1908 from the seaweed Laminaria japonica (kombu) by aqueous extraction and crystallization, calling its taste umami.[Manuf. 8] Ikeda noticed that dashi, the Japanese broth of katsuobushi and kombu, had a unique taste not yet scientifically described (not sweet, salty, sour or bitter).[Manuf. 8] To verify that ionized glutamate was responsible for umami, he studied the taste properties of glutamate salts: calcium, potassium, ammonium and magnesium glutamate. All these salts elicited umami and a metallic taste due to the other minerals. Of them, sodium glutamate was the most soluble and palatable and the easiest to crystallize.[citation needed] Ikeda called his product "monosodium glutamate", and submitted a patent to produce MSG;[Gov. 4] the Suzuki brothers began commercial production of MSG in 1909 as Aji-no-moto ("essence of taste").[Manuf. 9][Manuf. 10][5]

Use[edit]

Pure MSG is reported not to have a pleasant taste until it is combined with a savory aroma.[Manuf. 11] The basic sensory function of MSG is attributed to its ability to enhance savory taste-active compounds when added in the proper concentration.[3] The optimum 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.[6] There is also an interaction between MSG and salt (sodium chloride) and other umami substances, such as nucleotides.[citation needed]

MSG can be used to reduce the intake of sodium, which contributes to hypertension, heart disease and stroke.[Gov. 5] With appropriate MSG use, salt can be reduced by 30 to 40 percent without a perceived reduction in saltiness.[3]

The sodium content (in mass percent) of MSG—12 percent—is about one-third of that in sodium chloride (39 percent).[Manuf. 12] Although other salts of glutamate have been used in low-salt soups, they are less palatable than MSG.[Manuf. 13]

Safety[edit]

MSG has been used for more than 100 years to season food, with a number of studies conducted on its safety. International and national bodies governing food additives currently consider MSG safe for human consumption as a flavor enhancer.[Gov. 6] An MSG symptom complex was originally called "Chinese restaurant syndrome" when Robert Ho Man Kwok reported symptoms he felt after an American-Chinese meal. Kwok suggested possible reasons for his symptoms, including alcohol (from cooking with wine), sodium and MSG; however, a number of symptoms have become associated with MSG.[7] The anecdotal list of non-specific symptoms has grown. Under normal conditions, humans can metabolize relatively large quantities of glutamate. The median lethal dose (LD50) is between 15 and 18 g/kg body weight in rats and mice, respectively, five times greater than the LD50 of salt (3 g/kg in rats). The use of MSG as a food additive and the natural level of glutamic acid in foods are not toxicological concerns in humans.[Gov. 6]

A 1995 report from the Federation of American Societies for Experimental Biology (FASEB) for the United States Food and Drug Administration (FDA) concluded that MSG is safe when "eaten at customary levels" and, although a subgroup of otherwise-healthy individuals develop an MSG symptom complex when exposed to 3g of MSG in the absence of food, MSG causality has not been established because the symptom reports are anecdotal.[8]

According to the report, there is no data to support the role of glutamate in chronic disease. A controlled, double-blind, multi-location clinical trial failed to demonstrate a relationship between the MSG symptom complex and actual MSG consumption. No statistical association has been demonstrated, and the few responses were inconsistent. No symptoms were observed when MSG was administered with food.[7][9][10][11]

Adequately controlling for experimental bias includes a double-blind, placebo-controlled experimental design (DBPC) and administration by capsule, because of the unique aftertaste of glutamates.[10] In a study by Tarasoff and Kelly (1993), 71 fasting participants were given 5g of MSG and then a standard breakfast. There was one reaction (to the placebo, in a self-identified MSG-sensitive individual).[7] A study by Geha et al. (2000) tested the reaction of 130 subjects with a reported sensitivity to MSG. Multiple DBPC trials were performed, with subjects exhibiting at least two symptoms continuing. Two people out of the 130 responded to all four challenges. Because of the low prevalence, the researchers concluded that a response to MSG was not reproducible.[12]

Studies exploring MSG's role in obesity have yielded mixed results.[13][14] Although several studies have investigated anecdotal links between MSG and asthma, current evidence does not support a causal association.[15] Since glutamates are important neurotransmitters in the human brain, playing a key role in learning and memory, ongoing neurological studies indicate a need for further research.[16]

It has also been suggested that fear of MSG may reflect anti-Asian racism, with MSG being seen as an 'Oriental', alien arrival in Western cooking, likely to be dangerous.[17][18][19] Food critic Jeffrey Steingarten argued that fear of MSG should be seen as a Western-centric mindset, lacking awareness of its common use in Far Eastern cooking without apparent problems: "If MSG is a problem, why doesn't everyone in China have a headache?"[20][21]

Australia and New Zealand[edit]

Food Standards Australia New Zealand (FSANZ) has extensively documented MSG.[Gov. 7] The FSANZ MSG technical report concludes, "There is no convincing evidence that MSG is a significant factor in causing systemic reactions resulting in severe illness or mortality. The studies conducted to date on Chinese Restaurant Syndrome (CRS) have largely failed to demonstrate a causal association with MSG. Symptoms resembling those of CRS may be provoked in a clinical setting in small numbers of individuals by the administration of large doses of MSG without food. However, such affects are neither persistent nor serious and are likely to be attenuated when MSG is consumed with food. In terms of more serious adverse effects such as the triggering of bronchospasm in asthmatic individuals, the evidence does not indicate that MSG is a significant trigger factor."[Gov. 8]

However, the FSANZ MSG report says that although there is no data available on average MSG consumption in Australia and New Zealand, "data from the United Kingdom indicates an average intake of 590 mg/day, with extreme users (97.5th percentile consumers) consuming 2330 mg/day." (Rhodes et al. 1991) In a highly seasoned restaurant meal, intakes as high as 5000 mg or more may be possible (Yang et al. 1997). When very large doses of MSG (>5g MSG in a bolus dose) are ingested, plasma glutamate concentration will significantly increase. However, the concentration typically returns to normal within two hours. In general, foods providing metabolizable carbohydrate significantly attenuate peak plasma glutamate levels at doses up to 150 mg/kg body weight. Two earlier studies—the 1987 Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the 1995 Federation of American Societies for Experimental Biology (FASEB)—concluded, "there may be a small number of unstable asthmatics who respond to doses of 1.5 – 2.5g of MSG in the absence of food." The FASEB evaluation concluded, "sufficient evidence exists to indicate some individuals may experience manifestations of CRS when exposed to a ≥3g bolus dose of MSG in the absence of food."[Gov. 8]

Standard 1.2.4 of the Australia and New Zealand Food Standards Code requires MSG to be labeled in packaged foods. The label must have the food-additive class name (e.g. "flavour enhancer"), followed by the name of the additive ("MSG") or its International Numbering System (INS) number, 621.[Gov. 9]

United States[edit]

MSG is one of several forms of glutamic acid found in foods, in large part because glutamic acid (an amino acid) is pervasive in nature. Glutamic acid and its salts may be present in a variety of other additives, including hydrolyzed vegetable protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts and protein isolate, which must be specifically labeled. Since 1998, MSG cannot be included in the term "spices and flavorings". The ribonucleotide food additives disodium inosinate and disodium guanylate are usually used with monosodium glutamate-containing ingredients. However, the term "natural flavor" is used by the food industry for glutamic acid (chemically similar to MSG, lacking only the sodium ion). The FDA does not require disclosure of components and amounts of "natural flavor."[Gov. 10]

The FDA considers labels such as "no MSG" or "no added MSG" misleading if the food has ingredients which are sources of free glutamate, such as hydrolyzed protein. In 1993, it proposed adding "contains glutamate" to the common names of certain hydrolyzed proteins with substantial amounts of glutamate.[citation needed]

Production[edit]

MSG 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).[Manuf. 9] Wheat gluten was originally used for hydrolysis because it contains more than 30g of glutamate and glutamine in 100g of protein. As demand for MSG increased, chemical synthesis and fermentation were studied.[citation needed] The polyacrylic fiber industry began in Japan during the mid-1950s, and acrylonitrile was adopted as a base material to synthesize MSG.[Manuf. 14]

Most global MSG production is currently by bacterial fermentation in a process similar to making vinegar or yogurt. Sodium is added later, for neutralization. During fermentation, corynebacteria—cultured with ammonia and carbohydrates from sugar beets, sugar cane, tapioca or molasses—excrete amino acids into a culture broth from which L-glutamate is isolated. The Kyowa Hakko Kogyo Company developed industrial fermentation to produce L-glutamate.[Manuf. 15]

The conversion yield and production rate (from sugars to glutamate) continues to improve in the industrial production of MSG, keeping up with demand.[Manuf. 9] The product, after filtration, concentration, acidification and crystallization, is glutamate, sodium and water. A white, odorless, crystalline powder, in solution it dissociates into glutamate and sodium ions.[citation needed]

Chemical properties[edit]

MSG is freely soluble in water, but it is not hygroscopic and is insoluble in common organic solvents (such as ether).[22] It is generally stable under food-processing conditions. MSG 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.[Manuf. 10]

See also[edit]

References[edit]

Government[edit]

  1. ^ a b "Monosodium glutamate NF". NLM.NIH.gov. U.S. National Library of Medicine, ChemIDplus. Retrieved August 11, 2014. 
  2. ^ "Questions and Answers on Monosodium glutamate (MSG)". U.S. Food and Drug Administration. November 19, 2012. Retrieved February 4, 2014. 
  3. ^ "Current EU approved additives and their E Numbers". Food.gov.uk. 2010-11-26. Retrieved 2012-01-30 
  4. ^ Ikeda K (1908). "A production method of seasoning mainly consists of salt of L-glutamic acid". Japanese Patent 14804.
  5. ^ Legetic B, Pan American Health Organization (United Nations), Washington DC, USA; Campbell N, Departments of Medicine, Community Health Sciences, and Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Canada. (August 2012). "Reducing salt intake in the Americas: Pan American Health Organization actions". J Health Commun 2: 37–48. doi:10.1080/10810730.2011.601227. PMID 21916712. 
  6. ^ a b Walker R, Lupien JR, School of Biological Sciences, University of Surrey, UK, and Food and Nutrition Division, FAO of the United Nations, Italy. (April 2000). "The safety evaluation of monosodium glutamate". Journal of Nutrition 130 (4S Suppl): 1049S–52S. PMID 10736380. 
  7. ^ "Monosodium glutamate search". FoodStandards.gov.au. Food Standards Australia New Zealand, Health Minister Chair, Peter Dutton MP. Retrieved August 13, 2014. 
  8. ^ a b Technical Report.doc "MONOSODIUM GLUTAMATE, A Safety Assessment, TECHNICAL REPORT SERIES NO. 20". FoodStandards.gov.au. Food Standards Australia New Zealand, Health Minister Chair, Peter Dutton MP. June 2003. ISBN 0642345201. ISSN 1448-3017. Retrieved August 13, 2014. 
  9. ^ "Standard 1.2.4 Labelling of Ingredients". Food Standards Code. Food Standards Australia New Zealand. Archived from the original on 2010-08-21. Retrieved May 15, 2010. 
  10. ^ "CFR - Code of Federal Regulations Title 21, Vol 6, Part 501, Subpart B--Specific Animal Food Labeling Requirements". FDA.gov. U.S. Food and Drug Administration. Retrieved August 13, 2014. 

Manufacturers and suppliers[edit]

  1. ^ Ninomiya K, Technical Committee , Umami Manufacturers Association of Japan (1998). "Natural occurrence". Food Reviews International 14 (2 & 3): 177–211. doi:10.1080/87559129809541157. 
  2. ^ Singh, K. K.; Desai, Pinakin, Director. "Glutamate Chemical". TriveniInterChem.com. Riveni InterChem of Triveni Chemicals, manufacturer & supplier of industrial chemicals, India. Retrieved August 11, 2014. 
  3. ^ Desmo Exports Limited, Chemical Manfacturers and Importers of India (2011). "Monosodium Glutamate (MSG)". DesmoExports.com. Desmo Exports. Retrieved August 11, 2014. 
  4. ^ "Accent Flavor Enhancer". AccentFlavor.com. B&G Foods, Inc. Retrieved August 11, 2014. 
  5. ^ "B&G Foods, Incorporated". Grocery.com. Retrieved August 13, 2014. 
  6. ^ "Monosodium glutamate(MSG)". AjiNoMoto.com. Ajin-No-Moto Group Worldwide. Retrieved August 11, 2014. 
  7. ^ "Ajinomoto, To Greet the Next 100 Years, Corporate Guide". Ajinomoto.com. Retrieved August 13, 2014. 
  8. ^ a b Lindemann, Bernd, Universität des Saarlandes, Medical Faculty, Physiology, Germany; Ogiwara Yoko, Ajinomoto Co., Inc., European Head Office, France; Ninomiya, Yuzo, Section Oral Function and Neurobiology, Department of Regulatory Oral Science, Kyushu University Graduate School, Japan. (November 2002). "The discovery of umami". Chem Senses 27 (9): 843–4. doi:10.1093/chemse/27.9.843. PMID 12438211. 
  9. ^ a b c Sano, Chiaki, Technology and Engineering Center, Ajinomoto Co, Japan. (September 2009). "History of glutamate production". The American Journal of Clinical Nutrition 90 (3): 728S–732S. doi:10.3945/ajcn.2009.27462F. PMID 19640955. 
  10. ^ a b Yamaguchi, Shizuko, Tokyo University of Agriculture, Japan; Ninomiya, Kumiko, Technical Committee, Umami Manufacturers Association of Japan. (1998). "What is umami?". Food Reviews International 14 (2 & 3): 123?138. doi:10.1080/87559129809541155. 
  11. ^ Rolls, Edmund T., Oxford Centre for Computational Neuroscience, United Kingdom, Supported by the Medical Research Council and in part by the International Glutamate Technical Committee, a nongovernmental organization funded by industrial producers and users of glutamate in food. (September 2009). "Functional neuroimaging of umami taste: what makes umami pleasant?". The American Journal of Clinical Nutrition 90 (3): 804S–813S. doi:10.3945/ajcn.2009.27462R. PMID 19571217. 
  12. ^ Yamaguchi, Shizuko, Central Research Laboratories, Ajinomoto Co., Japan; Takahashi, Chikahito, Central Research Laboratories, Ajinomoto Co., Japan. (January 1984). "Interactions of monosodium glutamate and sodium chloride on saltiness and palatability of a clear soup". Journal of Food Science 49 (1): 82?85. doi:10.1111/j.1365-2621.1984.tb13675.x. 
  13. ^ Ball P, Woodward D, Beard T, Shoobridge A, Ferrier M. Sponsorship: We acknowledge the financial support of the International Glutamate Technical Committee (IGTC), a nongovernmental organization funded by industrial producers and users of glutamate in food. (June 2002). "Calcium diglutamate improves taste characteristics of lower-salt soup". Eur J Clin Nutr 56 (6): 519–23. doi:10.1038/sj.ejcn.1601343. PMID 12032651. 
  14. ^ Yoshida T, Ajinomoto Co., Planning and Development Department, Japan. (1970). "Industrial manufacture of optically active glutamic acid through total synthesis". Chem Ing Tech 42 (9–10): 641?644. doi:10.1002/cite.330420912. 
  15. ^ Kinoshita Shukuo, Tokyo Research Laboratory, Kyowa Fermentation Industry Company; Udaka, Shigezo; Shimamoto, Masakazu. (1957). "Studies on amino acid fermentation. Part I. Production of L-glutamic acid by various microorganisms". J Gen Appl Microbiol 3 (3): 193?205. doi:10.2323/jgam.3.193. 

Other[edit]

  1. ^ Specter, Michael (November 3, 2014). "What’s So Bad About Gluten?". New Yorker magazine. Retrieved October 28, 2014. 
  2. ^ Ikeda K (November 2002). "New seasonings". Chem Senses 27 (9): 847–849. doi:10.1093/chemse/27.9.847. PMID 12438213. 
  3. ^ a b c Loliger J (April 2000). "Function and importance of Glutamate for Savory Foods". Journal of Nutrition 130 (4s Suppl): 915s–920s. PMID 10736352. 
  4. ^ Yamaguchi S (May 1991). "Basic properties of umami and effects on humans". Physiology & Behavior 49 (5): 833–841. doi:10.1016/0031-9384(91)90192-Q. PMID 1679557. 
  5. ^ Kurihara K (September 2009). "Glutamate: from discovery as a food flavor to role as a basic taste (umami)?". The American Journal of Clinical Nutrition 90 (3): 719S–722S. doi:10.3945/ajcn.2009.27462D. PMID 19640953. 
  6. ^ Kawamura Y, Kare MR, ed. (1987). Umami: a basic taste. New York, NY: Marcel Dekker Inc. 
  7. ^ a b c Freeman, Matthew, CNP, mph, Clinical Instructor (Adult Nurse Practitioner), Ohio State University. He reviewed 40 years of documents on PubMed, Medline, Lexis-Nexus, and Infotrac, and concluded there is no consistent clinical data to support the belief that MSG can elicit a headache, and there is no consistent evidence to suggest that individuals may be uniquely sensitive to MSG. (2006). "Reconsidering the effects of monosodium glutamate: A literature review". Journal of the American Academy of Nurse Practitioners 18 (10): 482–6. doi:10.1111/j.1745-7599.2006.00160.x. PMID 16999713. 
  8. ^ Raiten DJ, Talbot JM, Fisher KD (1996). "Executive Summary from the Report: Analysis of Adverse Reactions to Monosodium Glutamate (MSG) --no summary available, 8/11/2014.". Journal of Nutrition 126 (6): 2891S–2906S. PMID 7472671. 
  9. ^ Geha RS, Beiser A, Ren C et al. (April 2000). "Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study". J. Nutr. 130 (4S Suppl): 1058S–62S. PMID 10736382. 
  10. ^ a b Tarasoff L., Kelly M.F. (1993). "Monosodium L-glutamate: a double-blind study and review". Food Chem. Toxicol. 31 (12): 1019–35. doi:10.1016/0278-6915(93)90012-N. PMID 8282275. 
  11. ^ Walker R (October 1999). "The significance of excursions above the ADI. Case study: monosodium glutamate". Regul. Toxicol. Pharmacol. 30 (2 Pt 2): S119–21. doi:10.1006/rtph.1999.1337. PMID 10597625. 
  12. ^ Willams, A. N., and Woessner, K.M. (2009). "Monosodium glutamate 'allergy': menace or myth?". Clinical & Experimental Allergy 39 (5): 640?646. doi:10.1111/j.1365-2222.2009.03221.x. 
  13. ^ Shi, Z; Luscombe-Marsh, ND; Wittert, GA; Yuan, B; Dai, Y; Pan, X; Taylor, AW (2010). "Monosodium glutamate is not associated with obesity or a greater prevalence of weight gain over 5 years: Findings from the Jiangsu Nutrition Study of Chinese adults". The British journal of nutrition 104 (3): 457–63. doi:10.1017/S0007114510000760. PMID 20370941. 
  14. ^ Nicholas bakalar (August 25, 2008). "Nutrition: MSG Use Is Linked to Obesity". The New York Times. Retrieved 2010-11-10. "Consumption of monosodium glutamate, or MSG, the widely used food additive, may increase the likelihood of being overweight, a new study says." 
  15. ^ Stevenson, D. D. (2000). "Monosodium glutamate and asthma". J. Nutr. 130 (4S Suppl): 1067S–73S. PMID 10736384. 
  16. ^ Nicholas J. Maragakis, MD; Jeffrey D. Rothstein, MD, PhD (2001;58:365-370.). "Glutamate Transporters in Neurologic Disease". Retrieved 2010-11-10.  Check date values in: |date= (help)
  17. ^ Mahoney, John. "The Notorious MSG’s Unlikely Formula For Success". Buzzfeed. Retrieved 12 November 2014. 
  18. ^ Dickerman, Sarah. "Could MSG make a comeback?". Slate magazine. 
  19. ^ Ibanga, Imaeyen. "China food scare: a dash of racism". ABC News. Retrieved 12 November 2014. 
  20. ^ Haber, Barbara. "Life on the Culinary Edge". Harvard Magazine. Retrieved 12 November 2014. 
  21. ^ Renton, Alex. "If MSG is so bad for you, why doesn't everyone in Asia have a headache?". The Guardian. Retrieved 12 November 2014. 
  22. ^ Win. C., ed. (1995). Principles of Biochemistry. Boston, MA: Brown Pub Co. 

External links[edit]