If you have ever enjoyed the savory flavor of soy sauce or the rich, full flavor of Parmesan cheese, then you have experienced the taste sensation known as umami. The term “umami” was first coined in 1908 by Dr. Kikunae Ikeda to describe the unique savory taste of seaweed broth [1,2]. Although umami was initially associated only with Asian cuisines, researchers all over the world have now established umami as one of the five basic taste groups [3]. In his original study of umami, Dr. Ikeda isolated the amino acid glutamate from dried seaweed and found that this molecule was sufficient to create a strong umami flavor [1]. As an amino acid, glutamate is an important component of proteins and occurs naturally in all living things. When it is not incorporated into a protein, “free glutamate” can readily bind to glutamate receptors in our taste buds to trigger the umami taste sensation [4]. Despite their different names, glutamate, glutamic acid, and monosodium glutamate are essentially the same molecule and behave the same way in our bodies.
Since the original discovery of glutamate, scientists have identified additional molecules that contribute to the umami taste sensation. The nucleotides inosine 5ʹ-monophosphate (IMP) and guanosine 5ʹ -monophosphate (GMP) are responsible for the umami taste of bonito and shiitake mushrooms, respectively [5]. Because nucleotides make up our genetic material, molecules like IMP and GMP are ubiquitous in living organisms. Interestingly, IMP and GMP alone do not have strong umami flavor but can synergistically enhance the umami sensation of glutamate [4,6].
