When taste buds were discovered in the 19th century, it was thought that only four "primary" tastes could be picked up by the human tongue - salty, sweet, bitter and sour. This thought was continued until the early 1900's when a Japanese scientist exploring a taste phenomenon in Japanese cooking changed this concept. Dashi, a stock made from Kombu ( Kelp; a seaweed) has been an integral part of Japanese cooking for a very long time. It was found that foods cooked with Dashi, were given a delicious, complex taste that could not be  attributed to any one or combination of the four "primary' tastes. Why this was so was not clear until, in 1908,  Dr. Kikunae Ikeda, a Japanese scientist at Tokyo Imperial University (now called The University of Tokyo)  discovered that glutamate (glutamic acid) was its  main flavor ingredient in Dashi and called the new taste sensation. "Umami", a Japanese word that has no exact  English translation but is interpreted as "savory" or "delicious" or "meaty" taste. After the discovery of glutamate as contributing to the Umami taste, other substances which gave a Umami taste were discovered in other very popular items used in Japanese cooking: inosinate found in  Bonito flakes - flakes shaved from dried, fermented  Bonito fish (also known as Skipjack Tuna) and guanylate found in Shitake mushroom stock. In the 1980's, further studies established that Umami associated with high glutamate - containing foods actually constituted a FIFTH taste component. Remember when most Chinese restaurants used monosiodiun glutamate (MSG) in their dishes. This was to give their food a UMAMI taste. Since that time, many UMAMI rich foods have been identified; seaweed, beef, tomatoes. Parmesan cheese, anchovies, Shitake and Enoki mushrooms, Asian fish and Soy sauces, among others.The Umami taste sensation is most intense in combination with salt: thus, a sprinkling of salt on a tomato intensifies its taste.Today Umami as a fifth taste is universally accepted. While the UMAMI taste is now established in a scientific sense, for centuries people around the world, INTUITIVELY, have prepared sauces and condiments which add UMAMI taste to dishes. Garum was a fish sauce made first by the Greeks and then the Romans.The Greeks made a sauce called "garos' a Greek word for a type of fish. Romans loved the sauce, took it over and made it their own way; salting Mackerel fish, letting it ferment in the sun and then filtering the fermented liquid to use as a sauce. Tomatoes were brought to Europe when Columbus discovered the New World. The Italians embraced the UMAMI containing tomato as the basis for many of their famous sauces. Asian cultures have used many UMAMI containing fermented products; the Soy and fish sauces of China, Japan, Vietnam . Thailand, etc and the British have their anchovy containing Worchester sauce. Science aside, TASTE wins out.