The fifth taste has a long history in cooking but it is only recently that it has been attributed to glutamate, with its culinary effects fully understood.
When we talk about 'the fifth taste' or Umami, we refer to a unique flavour balancing & amplifying ingredient. Glutamate has a long history in cooking. Fermented sauces rich in glutamate were used widely in ancient Rome, in medieval Byzantine and Arab cuisine. Fermented sauces made of fish or soy have histories going back to the 3rd century in China.
In the late-1800s, French Chef Auguste Escoffier, who opened restaurants in Paris and London, created meals that combined umami with salty, sour, sweet and bitter tastes. He did not know the chemical source of this unique quality, however. Until recently, the West had little scientific interest in what made food taste particularly good. It is only with the popularity of molecular cuisine that western chefs became fascinated with exploring the chemical factors implicated in the sensory appeal of food.
Umami as a separate taste
Umami was first scientifically identified in 1908 by Dr Kikunae Ikeda, a professor at the University of Tokyo. In his laboratory, Ikeda brewed 26 pounds of dried kombu seaweed into broth, and looked at each chemical component of the broth in turn. He was able to isolate about an ounce of one particular crystal that embodied the unique flavour of the dashi. He discovered that the salts present in kombu were high in glutamates, an amino acid. This flavour was not just salty, but more flavourful, leading ingredients to taste better with a richer, almost meaty flavour. He found that glutamate was responsible for the palatability of the broth from Kombu seaweed. He noticed that the taste of kombu dashi was distinct from sweet, sour, bitter, and salty and named it 'the fifth taste' - umami.
Later - in 1913 - Professor Shintaro Kodama, a disciple of Ikeda, discovered that dried bonito flakes contained another umami substance, called ribonucleotide IMP. In 1957, Akira Kuninaka realized that the ribonucleotide GMP present in shiitake mushrooms also conferred the umami taste.
One of Kuninaka's most important discoveries was the synergistic effect between ribonucleotides and glutamate. When foods rich in glutamate are combined with ingredients that have ribonucleotides, the resulting taste intensity is higher than would be expected from merely adding the intensity of the individual ingredients.
After Kikunae Ikeda’s discovery, the Ajinomoto Company (where he worked) would go on to produce the first commercial available form of glutamic salts for food preparation. It has been known as monosodium glutamate, or MSG, and its consumption is full of controversy.