Umami

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Umami, also referred to as savoriness, is one of the basic tastes sensed by specialized receptor cells present on the human and animal tongue. Umami (旨味?) is a loanword from Japanese meaning "good flavor" or "good taste" (noun).[1] "Brothy", "meaty", or "savory" have been proposed as alternative translations, however.[2][3] In as much as it describes the flavor common to savory products such as meat, cheese, and mushrooms, umami is similar to Brillat-Savarin's concept of osmazome, an early Western attempt to describe the main flavoring component of meat as extracted in the process of making stock.

The umami taste is due to the detection of the carboxylate anion of glutamic acid, a naturally occurring amino acid common in meat (particularly bacon), cheese, broth, stock, and other protein-heavy foods. Salts of glutamic acid, known as glutamates, easily ionize to give the same carboxylate form and therefore the same taste. For this reason, they are used as flavor enhancers. The most commonly used of these is monosodium glutamate (MSG). While the umami taste is due to glutamates, 5'-ribonucleotides such as guanosine monophosphate (GMP) and inosine monophosphate (IMP) greatly enhance its perceived intensity. Since these ribonucleotides are also acids, their salts are sometimes added together with glutamates to obtain a synergistic flavor enhancement effect.[2][4]

  • 1 Excitatory substances
  • 2 Taste receptors
  • 3 Bacon
  • 4 See also
  • 5 Notes
  • 6 References
  •  

  • 7 External links

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Excitatory substances

Main article: Glutamic acid (flavor)
See also: Guanosine monophosphate and Inosine monophosphate

Umami as a separate taste was first identified in 1908 by Kikunae Ikeda of the Tokyo Imperial University while researching the strong flavor in seaweed broth.[3] Ikeda isolated monosodium glutamate (MSG) as the chemical responsible and, with the help of the Ajinomoto company, began commercial distribution of MSG products.

Glutamate has a long history in cooking.[5] It is naturally found in East and Southeast Asian foods, such as soy sauce and fish sauce, and in Italian foods like Parmesan cheese, anchovies and ripe tomatoes (though tomatoes did not originate in Europe). It is also prevalent in seafood, such as lobster, crabs, and shrimp.[6]

Taste receptors

Umami has been described in biochemical studies identifying the actual taste receptor responsible for the sense of umami, a modified form of mGluR4[7] named "taste-mGluR4."

Umami tastes are initiated by these specialized receptors, with subsequent steps involving secretion of neurotransmitters including serotonin.[8] Other evidence indicates guanosine derivatives may interact with and boost the initial umami signal.[9]

Cells responding to umami taste stimuli do not possess typical synapses, but instead secrete the neurotransmitter ATP in a mechanism exciting sensory fibers that convey taste signals to the brain.

In monkey studies, most umami signals from taste buds excite neurons in the orbitofrontal cortex of the brain, showing spatially specific characteristics:[10]

  • Single neurons having vigorous responses to sodium glutamate also respond to glutamic acid
  • Some neurons display a mechanism of satiety.

The stomach can "taste" sodium glutamate using glumate receptors[11] and this information is passed to the lateral hypothalamus and limbic system in the brain as a palatability signal through the vagus nerve.[12]

Bacon

Arun Gupta of The Indypendent has pointed out how bacon in particular possesses six ingredient types of umami, which elicits an addictive neurochemical response.[13] According to Gupta "the chain lards on bacon in particular" give foods a "high flavor profile" creating a "one-of-a-kind product that has no taste substitute."[14] This led Dr. David Kessler, author of The End of Overeating, to note how the standard joke in the restaurant chain industry goes, "When in doubt, throw cheese and bacon on it."[14]

See also

  • Inosine monophosphate

Notes

  1. ^ http://jisho.org/words?jap=%E6%97%A8%E5%91%B3&eng=&dict=edict
  2. ^ a b Chandrashekar J, Hoon MA, Ryba NJ, Zuker CS (November 2006). "The receptors and cells for mammalian taste". Nature 444 (7117): 288–94. doi:10.1038/nature05401. PMID 17108952. 
  3. ^ a b Ikeda K (November 2002). "New seasonings". Chemical Senses 27 (9): 847–9. doi:10.1093/chemse/27.9.847. PMID 12438213.  (partial translation of Ikeda, Kikunae (1909). "New Seasonings[japan.]". Journal of the Chemical Society of Tokyo 30: 820–836. )
  4. ^ Yasuo T, Kusuhara Y, Yasumatsu K, Ninomiya Y (October 2008). "Multiple receptor systems for glutamate detection in the taste organ". Biological & Pharmaceutical Bulletin 31 (10): 1833–7. doi:10.1248/bpb.31.1833. PMID 18827337. 
  5. ^ Lehrer, Jonah (2007). Proust was a Neuroscientist. Mariner Books. doi:0908/1043570. ISBN 9780547085906. 
  6. ^ Moskin, Julia (5 March 2008). "Yes, MSG, the Secret Behind the Savor". New York Times. http://nytimes.com/2008/03/05/dining/05glute.html. Retrieved 9 August 2008. 
  7. ^ Nelson G, Chandrashekar J, Hoon MA, et al. (2002). "An amino-acid taste receptor". Nature 416 (6877): 199–202. doi:10.1038/nature726. PMID 11894099. 
  8. ^ Roper SD (August 2007). "Signal transduction and information processing in mammalian taste buds". Pflügers Archiv 454 (5): 759–76. doi:10.1007/s00424-007-0247-x. PMID 17468883. 
  9. ^ Daniels, S (February 18, 2008). "Scientists develop new umami taste enhancers". FoodNavigator.com-Europe. http://foodnfoodnavigator.com/news/ng.asp?id=83328-umami-msg-gmp. 
  10. ^ Rolls ET (April 2000). "The representation of umami taste in the taste cortex". The Journal of Nutrition 130 (4S Suppl): 960S–5S. PMID 10736361. http://jn.nutrition.org/cgi/pmidlookup?view=long&pmid=10736361. 
  11. ^ Uematsu A, Tsurugizawa T, Kondoh T, Torii K. (2009). Conditioned flavor preference learning by intragastric administration of L-glutamate in rats. Neurosci Lett. Feb 27;451(3):190-3. PMID 19146916
  12. ^ Uematsu A, Tsurugizawa T, Uneyama H, Torii K. (2010). Brain-gut communication via vagus nerve modulates conditioned flavor preference. Eur J Neurosci. 31(6):1136-43. doi:10.1111/j.1460-9568.2010.07136.x PMID 20377626
  13. ^ "Bacon as a Weapon of Mass Destruction" - video report with Arun Gupta by Democracy Now!, August 3, 2009
  14. ^ a b Gonzo Gastronomy: How the Food Industry Has Made Bacon a Weapon of Mass Destruction by Arun Gupta, AlterNet, October 9, 2010

References

  • Flavor Chemistry: Thirty Years of Progress By Roy Teranishi, Emily L. Wick, Irwin Hornstein; Article: Umami and Food Palatability, by Shizuko Yamaguchi and Kumiko Ninomiya. ISBN 0306461994
  • Barbot, Pascal; Matsuhisa, Nobu; and Mikuni, Kiyomi. Foreword by Heston Blumenthal. Dashi and Umami: The Heart of Japanese Cuisine. London: Eat-Japan / Cross Media, 2009

External links

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