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Umami

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For the record label, see Umami Records.
Ripe tomatoes are rich in umami components.

Umami (IPA: [uː mɑː mi]), popularly referred to as savoriness,[1][2][3][4][5] is one of the five basic tastes together with sweet, sour, bitter, and salty. Umami is a loanword from the Japanese umami (うま味) meaning "savory taste".[6] This particular writing was chosen by Professor Ikeda from umai (うまい) "delicious" and mi (味) "taste". The Chinese characters 旨味 are used to described a more general meaning, when a particular food is delicious. For long time, scientists debated that umami were a basic taste; but in 1985 at the first Umami International Symposium in Hawaii, the term Umami was officially recognized as the scientific term to describe the taste of glutamates and nucleotides. Now it is widely accepted as the fifth basic taste. Umami represents the taste imparted by the amino acid L-glutamate and 5’-ribonucleotides such as guanosine monophosphate (GMP) and inosine monophosphate (IMP).[7] It is described as a pleasant "brothy" or "meaty" taste with a long lasting, mouthwatering and coating sensation over the tongue. This is due to the detection of the carboxylate anion of glutamate in specialized receptor cells present on the human and animal tongue.[8][9] Its fundamental effect is the ability to balance and round the total flavor of a dish. Umami clearly enhances the palatability of soups and a wide variety of foods that are not sweet. Fruits, fruit juices and some dairy products do not match well with umami taste (for review Beauchamp, 2009).[10] Glutamate in acid form (Glutamic acid) imparts little umami taste; whereas the salts of glutamic acid, known as glutamates, can easily ionize and give an intense umami taste. While the umami taste is due to glutamates, GMP and IMP amplifies its perceived intensity.[9][11]

Discovery of umami taste

Kikunae Ikeda.

Glutamate has a long history in cooking.[12] Fermented fish sauces (garum), rich in glutamate, were already used in ancient Rome.[13] But umami was not properly identified until 1908 by the scientist Kikunae Ikeda,[14] a Professor of the Tokyo Imperial University. He found that glutamate was responsible for the palatability of the broth from kombu seaweed. He noticed that the taste of kombu dashi was distinct from sweet, sour, bitter and salty and named it umami. Later, a disciple of professor Ikeda, Shintaro Kodama, discovered in 1913 that dried bonito flakes contained another umami substance. This was the ribonucleotide IMP. And in 1957, Akira Kuninaka realized that the ribonucleotide GMP present in shiitake mushrooms also conferred the umami taste. But one of Kuninaka’s most important discoveries was the synergistic effect between ribonucleotides and glutamate. When foods rich in glutamate are combined with ingredients that have ribonucleotides, the resulting taste intensity is higher than the sum of both ingredients. This is why Japanese make dashi with kombu seaweed and dried bonito flakes, or Italians sprinkle Parmesan cheese on tomato sauce. The umami taste sensation of those ingredients mixed together surpasses the taste of each one alone.

Properties of umami taste

Umami increases palatability, salivation, and can reduce considerably the use of salt (sodium chloride) without compromising taste acceptability.[7][15] It can be especially useful to improve the palatability of foods low in fat or rich in vegetables. Moreover, recent research suggests that umami substances can improve protein digestion and absorption of essential amino acids.[16][17] Some population groups, such as the elderly, whose taste and smell sensitivity is impaired by age and multiple medications, may benefit with umami. The loss of taste and smell can contribute to a poor nutritional status increasing their risk of disease.[18]

Foods rich in umami

Many foods that we consume daily are rich in umami. A person's first encounter with umami is with breast milk.[19][20] Breast milk contains roughly the same amount of umami as Japanese broths or bouillon, called dashi. Umami taste is common to foods that contain high levels of L-glutamate, IMP and GMP, most notably in fish, cured meats, vegetables (e.g. mushrooms, ripe tomatoes) or green tea, and fermented and aged products (e.g. cheeses, shrimp pastes, soy sauce, etc.).[7]
Japanese dashi gives a very pure umami taste sensation because of its high content of L-glutamate from sea kombu (Laminaria japonica) and inosinate from dried bonito flakes (katsuobushi) or small dried sardines (niboshi). Western broths and bouillons give a more complex taste because of a wider mixture of amino acids from bones, meats and vegetables.

Taste receptors

Biochemical studies have identified the taste receptors responsible for the sense of umami, a modified form of mGluR4, mGluR1 and taste receptor type 1 (T1R1 + T1R3).[21][22][23] The New York Academy of Sciences corroborated their acceptance stating that "Recent molecular biological studies have now identified strong candidates for umami receptors, including the heterodimer T1R1/T1R3, and truncated tye 1 and 4 metabotropic glutamate receptors missing most of the N-terminal extracellular domain (taste-mGluR4 and truncated-mGluR1) and brain-mGluR4 …The finding that human T1R1/T1R3 heterologously expressed in human embryonic kidney cells preferentially responds to glutamate, provides strong molecular evidence for specific umami detection in humans. However, these other receptors remain candidates and the role of each type of receptor in taste bud cells remains unclear."[8]

Umami tastes are initiated by these specialized receptors, with subsequent steps involving secretion of neurotransmitters including serotonin.[24] Other evidence indicates guanosine derivatives may interact with and boost the initial umami signal.[25]

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:[26]

  • 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[27] and this information is passed to the lateral hypothalamus and limbic system in the brain as a palatability signal through the vagus nerve.[28]

Notes

  1. ^ "What exactly is umami?". The Umami Information Center.
  2. ^ "You say savory, I say umami".
  3. ^ Issie Lapowsky (9 February 2010). "Umami, savory 'fifth taste,' now available in a tube in grocery stores". NY Daily News. Retrieved 1 January 2011.
  4. ^ "Cambridge Advanced Learner's Dictionary". Cambridge University Press. Retrieved 1 January 2011.
  5. ^ "Merriam-Webster English Dictionary". Merriam-Webster, Incorporated. Retrieved 1 January 2011.
  6. ^ Jim Breen. "[[EDICT]]'s entry for umami". Retrieved 31 December 2010. {{cite web}}: URL–wikilink conflict (help)
  7. ^ a b c Yamaguchi S, Kumiko N (2000). "Umami and Food Palatability". Journal of Nutrition. 130 (4): 921S–26S. PMID 10736353. {{cite journal}}: Unknown parameter |month= ignored (help)
  8. ^ a b Thomas E. Finger, ed. (2009). International Symposium on Olfaction and Taste, Volume 1170. Hoboken,NJ: The Annals of the New York Academy of Sciences.
  9. ^ a b Chandrashekar J, Hoon MA, Ryba NJ, Zuker CS (2006). "The receptors and cells for mammalian taste". Nature. 444 (7117): 288–94. doi:10.1038/nature05401. PMID 17108952. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  10. ^ Beauchamp G (2009). "Sensory and receptor responses to umami: an overview of pioneering work". Am J Clin Nutr. 90 (3): 723S–7S. PMID 19571221. {{cite journal}}: Unknown parameter |month= ignored (help)
  11. ^ Yasuo T, Kusuhara Y, Yasumatsu K, Ninomiya Y (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. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  12. ^ Lehrer, Jonah (2007). Proust was a Neuroscientist. Mariner Books. doi:0908/1043570. ISBN 9780547085906. {{cite book}}: Check |doi= value (help)
  13. ^ Smriga M, Mizukoshi T, Iwata D, Sachise E, Miyano H, Kimura T, Curtis R (2010). "Amino acids and minerals in ancient remnants of fish sauce (garum) sampled in the "Garum Shop" of Pompeii, Italy". Journal of Food Composition and Analysis. 23 (5): 442–446. doi:10.1016/j.jfca.2010.03.005. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  14. ^ Ikeda K (2002). "New seasonings". Chemical Senses. 27 (9): 847–9. doi:10.1093/chemse/27.9.847. PMID 12438213. {{cite journal}}: Unknown parameter |month= ignored (help) (partial translation of Ikeda, Kikunae (1909). "New Seasonings[japan.]". Journal of the Chemical Society of Tokyo. 30: 820–836.)
  15. ^ Uneyama H, Kawai M, Sekine-Hayakawa Y, Torii K (2009). "Contribution of umami taste substances in human salivation during meal". Journal of Medical Investigation. 56 (supplement): 197–204. doi:10.2152/jmi.56.197. PMID 20224181. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  16. ^ Zolotarev V, Khropycheva R, Uneyama H, Torii K (2009). "Effect of free dietary glutamate on gastric secretion in dogs". Ann NY Acad Sci. 1170 (International Symposium on Olfaction and Taste): 87–90. doi:10.1111/j.1749-6632.2009.03900.x. PMID 19686114. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  17. ^ Boutry C, Matsumoto H, Airinei G, Benamouzig R, Tome D, Blachier F, Bos C (2010). "Monosodium glutamate raises antral distension and plasma amino acid after a standard meal in humans". Am J Physiol Gastrointest Liver Physiol. doi:10.1152/ajpgi.00299.2010. PMID 21030612. {{cite journal}}: Text "Epub ahead of print" ignored (help)CS1 maint: multiple names: authors list (link)
  18. ^ Yamamoto S, Tomoe M, Toyama K, Kawai M, Uneyama H (2009). "Can dietary supplementation of monosodium glutamate improve the health of the elderly?". Am J Clin Nutr. 90 (3): 844S–849S. doi:10.3945/ ajcn.2009.27462X. PMID 19571225. {{cite journal}}: Check |doi= value (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  19. ^ Agostini C, Carratu B, Riva E, Sanzini E (2000). "Free amino acid content in standard infant formulas: comparison with human milk=Journal of American College of Nutrition". 19 (4): 434–438. PMID 10963461. {{cite journal}}: Cite journal requires |journal= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  20. ^ Agostini C, Carratu B, Boniglia C, Lammardo AM, Riva E, Sazini E (2000). "Free glutamine and glutamic acid increase in human milk through a three-month period". Journal of Pediatric Gastroenterology and Nutrition. 31 (5): 508–512. PMID 11144435. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  21. ^ Chaudhari N, Landin AM, Roper SD (2000). "A metabotropic glutamate receptor variant functions as a taste receptor". Nature Neuroscience. 3 (2): 113–119. doi:10.1038/72053. PMID 10649565.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ^ 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. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  23. ^ San Gabriel A, Uneyama H, Yoshie S, Torii K (2005). "Cloning and characterization of a novel mGluR1 variant from vallate papillae that functions as a receptor for L-glutamate stimuli". Chem Senses. 30 (Suppl): i25–i26. doi:10.1093/chemse/bjh095. PMID 15738140.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ Roper SD (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. {{cite journal}}: Unknown parameter |month= ignored (help)
  25. ^ Daniels, S (February 18, 2008). "Scientists develop new umami taste enhancers". FoodNavigator.com-Europe.
  26. ^ Rolls ET (2000). "The representation of umami taste in the taste cortex". The Journal of Nutrition. 130 (4S Suppl): 960S–5S. PMID 10736361. {{cite journal}}: Unknown parameter |month= ignored (help)
  27. ^ Uematsu, A; Tsurugizawa, T; Kondoh, T; Torii, K (2009). "Conditioned flavor preference learning by intragastric administration of L-glutamate in rats". Neuroscience letters. 451 (3): 190–3. doi:10.1016/j.neulet.2008.12.054. PMID 19146916.
  28. ^ 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.

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 0-306-46199-4
  • 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
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