In the early 20th century, Kikunae Ikeda thought a lot about soup. A Japanese chemist studied a seaweed and dried fish flake broth called dashi. Dashi has a very specific taste. Ikeda tried to isolate the molecules behind his distinctive taste. He was sure that there was some connection between the shape of the molecule and the perception of taste that it produces in humans. Eventually, Ikeda was able to isolate an important taste molecule from seaweed in dashi, glutamic acid. In 1909, Ikeda suggested that the savory sensations evoked by glutamate must be one of the primary tastes. He called it “umami”, which means “delicious” in Japanese.
But for a long time, his discovery was not recognized. First, Ikeda’s work remained in Japanese until it was finally translated into English in 2002. Secondly, the taste of umami is difficult to separate from others. It doesn’t get richer and clearer just by adding more glutamate, as is the case with sweet flavors, where you can add sugar and definitely taste the sweetness. “These are completely different tastes. If these flavors could be compared to color, then umami would be yellow and sweet would be red,” Ikeda notes in his article. Umami has a mild but lingering aftertaste associated with salivation. Umami itself does not taste good, but it does make a wide variety of dishes enjoyable.
More than a hundred years have passed. Scientists around the world now recognize that umami is a real and just as basic flavor as the others. Some people have suggested that perhaps umami is just a type of salinity. But if you look closely at the nerves that send messages from your mouth to your brain, you can see that umami and salty tastes operate through different channels.
Much of the acceptance of Ikeda’s ideas came about 20 years ago. After specific receptors were found in the taste buds that absorb amino acids. Numerous research groups have reported receptors that are specifically tuned to glutamate and other umami molecules that create a synergistic effect.
In a way, it’s not surprising that our body has evolved a way to sense the presence of amino acids, as they are critical to our survival. Human milk has levels of glutamate that are about the same as the dashi broth that Ikeda studied, so we’re probably familiar with the taste.
Ikeda, for his part, found a spice manufacturer and started producing his own line of umami spices. It was monosodium glutamate, which is still produced today.
Are there other flavors?
A story with minds might make you wonder if there are other main flavors that we just don’t know about? Some researchers believe that we may have a sixth basic taste associated with fat. There are several good candidates for fat receptors on the tongue, and it is clear that the body reacts strongly to the presence of fat in food. However, by the time the fat levels are high enough that we can actually taste them, we don’t really like the taste.
However, there is another contender for the title of a new taste. Japanese scientists introduced the idea of ”kokumi” to the world. “Kokumi means a taste that cannot be expressed by the five basic tastes, and also includes distant tastes of the main tastes such as thickness, fullness, continuity, and harmony,” the Umami Information Center website says. Caused by a trio of linked amino acids, the kokumi sensation adds to the enjoyment of certain types of foods, most of which are unsweetened.
Harold McGee, a food writer, had the opportunity to sample some of the kokumi-inducing tomato sauce and cheese flavored potato chips at the 2008 Umami Summit in San Francisco. He described the experience: “The flavors seemed heightened and balanced, as if the volume control and EQ were on. They also seemed to somehow cling to my mouth – I felt it – and lasted longer before disappearing.