The noun umami denotes a category of taste corresponding to the ‘savoury’ flavour of free glutamates in various foods, especially protein-rich fermented and aged ones such as mature cheeses and soy sauce, specially the flavour of monosodium glutamate. Umami is sometimes described as a fifth basic taste alongside sweet, sour, salt, and bitter.
This Japanese word means deliciousness; it is from uma-, stem of umai, delicious, and -mi, suffix forming abstract nouns from adjectives (but the word is commonly written as if from -mi, taste).
In A text-book of Colloquial Japanese: based on the Lehrbuch der japanischen Umgangssprache by Dr. Rudolf Lange, revised English edition by Christopher Noss (1903), umami translates flavor and one of the exercises contains the following:
If there were no (are not) unsavory things, the flavor (umami mo) of delicious things would hardly be appreciated (understood).
However, umami was first scientifically identified by Kikunae Ikeda (1864-1936), of the College of Science, Imperial University of Tokyo, who wrote the following in New Seasonings, published in the Journal of the Chemical Society of Tokyo (1909):
Physiologists and psychologists recognize only the four tastes sour, sweet, salty and bitter. Other tastes are considered to be a mixture of these tastes. However, I believe that there is at least one other additional taste which is quite distinct from the four tastes. It is the peculiar taste which we feel as ‘umai’, arising from fish, meat and so forth. The taste is most characteristic of broth prepared from dried bonito and seaweed [Laminaria japonica]. While it is based on a subjective sensation, many people who are asked always agree to this conjecture either immediately or after brief consideration. Consequently, there can be little doubt that another taste exists in addition to the four tastes. I propose to call this taste ‘umami’ for convenience.
The following is the beginning of Similarity among different kinds of taste near the threshold concentration, published in Shinrigaku kenkyu: The Japanese journal of psychology of April 1963, by Masaaki Yoshida, of the Japan Woman’s University:
There are a number of theories concerning taste factors. Some identify only four factors, i.e., sweet, sour, bitter, and salty. Others assume more factors like freshness of acidulous spring, pungent taste of alcohol, astringency (shibumi) like tannin, or delicious taste (umami) of glutamic acid, etc. The purpose of the present study is to examine to what extent these taste factors are independent.