Mysterious or Ubiquitous "Umami"

We equate the taste sensation of savory deliciousness of tempeh with the Japanese word umami. 

Umami means “essence of deliciousness” in Japanese.  Historically, we defined taste as falling into four categories: sweet, sour, salty and bitter.  However in 2002, scientists discovered tongue receptors for a fifth taste: umami.

Umami is often described as a meaty deliciousness that further deepens flavor. Not only does it last longer than the other four tastes, but it also provides a sensation of mouth-fullness, balance, complexity, and of salivation. Umami fills our deep, primal desire for satisfying food.

Glutamate, an amino acid and ribonucleotide, is the primary source of umami. It is naturally occurring in animal meats, tomatoes, mushrooms, tea, miso, truffle oil, soy sauce, seaweeds, dairy, and many other foods.   When glutamic acid is bound up in a protein, we cannot detect it, so it has no flavor to us.  To be tasted, it needs to be liberated from protein. When we ferment legume and grain protein in foods like tempeh, we are breaking them down and freeing the amino acids to release umami flavors.

Sources:

Goldfield, H., Goodyear, D., & Kramer, J. (n.d.). You Think You Know Umami. The New Yorker. https://www.newyorker.com/culture/culture-desk/you-think-you-know-umami.

What is umami? 5 facts about umami: Everything about umami: Umami Global Website. Ajinomoto Group Global Website - Eat Well, Live Well. (n.d.). https://www.ajinomoto.com/aboutus/umami/5-facts. 

Rotkovitz, M. (n.d.). What Does Umami Taste Like? The Spruce Eats. https://www.thespruceeats.com/what-is-umami-1664724. 

Yamaguchi, S., & Ninomiya, K. (2000, April 1). Umami and Food Palatability. OUP Academic. https://academic.oup.com/jn/article/130/4/921S/4686627. 

Krulwich, R., & Lehrer, J. (2007, November 5). Sweet, Sour, Salty, Bitter ... and Umami. NPR. https://www.npr.org/templates/story/story.php?storyId=15819485. 

Ninomiya, K. (2015, January 26). Science of umami taste: adaptation to gastronomic culture. Flavour. https://flavourjournal.biomedcentral.com/articles/10.1186/2044-7248-4-13.