Abstract
Three umami substances (glutamate, 5′-inosinate, and 5′-guanylate) were found by Japanese scientists, but umami has not been recognized in Europe and America for a long time. In the late 1900s, umami was internationally recognized as the fifth basic taste based on psychophysical, electrophysiological, and biochemical studies. Three umami receptors (T1R1 + T1R3, mGluR4, and mGluR1) were identified. There is a synergism between glutamate and the 5′-nucleotides. Among the above receptors, only T1R1 + T1R3 receptor exhibits the synergism. In rats, the response to a mixture of glutamate and 5′-inosinate is about 1.7 times larger than that to glutamate alone. In human, the response to the mixture is about 8 times larger than that to glutamate alone. Since glutamate and 5′-inosinate are contained in various foods, we taste umami induced by the synergism in daily eating. Hence umami taste induced by the synergism is a main umami taste in human.
Highlights
In 1908, the active principle of seaweed kombu was identified as glutamate by Ikeda [1]
We found that canine chorda tympani nerves showed a large synergism between glutamate and 5-guanylate [8]
(1) In human and dog, sodium chloride largely enhances the responses to amino acids, sugars, and umami substances, while such enhancement is not seen in rodents
Summary
In 1908, the active principle of seaweed kombu was identified as glutamate by Ikeda [1]. Taste of glutamate is uniquely different from classical 4 basic tastes and he termed it umami [1]. 5-Inosinate from dried bonito [2] and 5-guanylate from dried shiitake mushroom [3] were found to have umami taste. There is a large synergism between glutamate and 5-inosinate or 5-guanylate. Monosodium glutamate (MSG) is usually used as an umami stimulus since glutamic acid itself has no umami taste. After the International Symposium, the psychophysical and electrophysiological studies showed that umami is independent of the four classical basic tastes. MGluR1, mGluR4, and T1R1 + T1R3 were identified to be receptors for umami taste. Based on these studies, umami was internationally recognized as the fifth basic taste. Dietary glutamate does not go to tissues such as brain and muscle
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
