Umami the Fifth Basic Taste: History of Studies on Receptor Mechanisms and Role as a Food Flavor

Abstract EN

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.