Inasmuch 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 (link in French), an early attempt to describe the main flavoring component of meat as extracted in the process of making stock.
Umami was first identified as a basic taste in 1908 by Kikunae Ikeda of the Tokyo Imperial University while researching the strong flavor in seaweed broth.[3][4] Ikeda isolated monosodium glutamate as the chemical responsible and, with the help of the Ajinomoto company, began commercial distribution of MSG products.
Taste receptors
Acknowledged subjectively as a special taste by Eastern civilizations for generations, umami has been described in biochemical studies identifying the actual taste receptor responsible for the sense of umami, a modified form of mGluR4[5] named "taste-mGluR4".
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. These taste receptors are located everywhere on the tongue.citation needed
There is a cortical map representation for the taste of glutamate separate from that of other taste stimuli like sweet (glucose), salt (sodium chloride), bitter (quinine), and sour (hydrochloric acid)
Single neurons having vigorous responses to sodium glutamate also respond to glutamic acid
Some neurons display a mechanism of satiety, indicating a process by which taste receptors in the mouth may interact with cortical neurons to curtail eating
Umami flavor is strongest when combined with aromas (e.g., monosodium glutamate and garlic), a result leading to speculation that glutamate may stimulate umami effects by acting simultaneously with the aromas, texture, and appearance of food.
^ The taste is also present in many snack foods, such as Doritos, Cheetos, and other fast foods. J. Moskin, "Yes, MSG, the Secret Behind the Savor", New York Times. 5 Mar 2008
^ Ikeda, Kikunae (1909). "New Seasonings[japan.]". Journal of the Chemical Society of Tokyo30: 820–836.
^ Nelson G, Chandrashekar J, Hoon MA, et al (2002). "An amino-acid taste receptor". Nature416 (6877): 199–202. doi:10.1038/nature726. PMID 11894099.
^[1] Roper SD. Signal transduction and information processing in mammalian taste buds. Pflugers Arch. 2007 Aug;454(5):759-76
^ Daniels S. Scientists develop new umami taste enhancers. FoodNavigator.com-Europe, February 18, 2008. [2]
^[3] Rolls ET. The representation of umami taste in the taste cortex. J Nutr. 2000 Apr;130(4S Suppl):960S-5S.
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