ARI SHAPIRO, HOST:
About a hundred years ago, a Japanese chemist named Dr. Kikunae Ikeda set out to solve a mystery - what made the taste of the soup stock dashi distinct from other tastes like salty, sweet, sour and bitter? He ultimately distilled a single compound from the stocks' seaweed. It was glutamate. Yet it was only recently that the taste associated with that compound was commonly acknowledged in the West. Chloee Weiner and Emily Kwong at NPR's science podcast Short Wave pick up the story.
EMILY KWONG, BYLINE: Glutamate is just an amino acid, a building block of protein. And Ikeda called the taste that comes from glutamate umami and, in 1909, published a paper in Japanese in the Journal of the Tokyo Chemical Society. He wrote...
UNIDENTIFIED ACTOR: (As Kikunae Ikeda) It is the peculiar taste which we feel as umai, meaning brothy, meaty or savory, arising from fish, meat and so forth. I propose to call this taste umami for convenience.
KWONG: Ikeda had discovered a fifth taste, but it would take nearly 100 years for umami to be accepted by the broader scientific community.
CHLOEE WEINER, BYLINE: It's kind of like a fable in the world of food and food journalism. It gets told a lot. But why the paper wasn't really recognized in the U.S. is complicated.
KWONG: It sounds like a science story.
WEINER: Yes. I mean, some of Ikeda's work was acknowledged in a really big way. After he isolated glutamate, he realized he had something delicious on his hands.
KWONG: Yeah.
WEINER: And then he founded a company called Ajinomoto and started mass producing a food additive called monosodium glutamate or, famously, MSG.
KWONG: Heart eyes - MSG. I didn't realize this for years, but MSG and umami are kind of the same thing.
WEINER: I didn't realize that until, like, a week ago.
KWONG: Chloee, we're such bad Asians.
WEINER: I know.
KWONG: We're bad Asians.
WEINER: I know. Anyway, here's how Sarah Tracy explains the MSG-umami relationship.
SARAH TRACY: Food scientists have talked for a long time about MSG as being the purest - most chemically pure, that is - specific, targeted way of stimulating what is now accepted as an umami taste response in the human body. So MSG is to umami what sucrose table sugar would be to sweetness.
WEINER: And there's this whole history of MSG's reception in the U.S. But the very short version is that MSG became really popular in Japan and the United States until this panic around MSG and so-called Chinese restaurant syndrome, which flared up in the 1960s and '70s.
KWONG: Yeah, I'm familiar with this. It's when, like, people dining at Chinese restaurants or eating foods high in MSG claim to feel ill afterward even though modern food scientists haven't been able to prove that there's any kind of link.
WEINER: Right. But back in the day, this idea was really widespread. And, you know, I think it was fueled in part by anti-Asian racism and xenophobia but also this movement against pesticides and a general wariness of chemicals.
KWONG: That's MSG's reputation a century ago. What was going on with Ikeda's umami research in all that time?
WEINER: Knowing how popular and controversial MSG was in the U.S., it seemed really strange to me that Ikeda's work on umami wasn't well-known.
KWONG: Yeah.
WEINER: I mean, one reason I can think of is that the 20th century was a really tense time between the United States and Japan. There was World War II, Japanese internment - a lot going on. But there were other factors, too, dating back even further. Victoria Lee, a history professor at Ohio University, told me that after World War I, nutrition research was booming in Japan, and flavor was a big part of it.
VICTORIA LEE: Fermented foods and seasonings like sake, soy sauce, miso were a large part of the diet in Japan and also a large part of the economy. And so research into the flavor components of those kinds of foods were an important part of rationalizing diet in Japan.
WEINER: By rationalizing the diet, Lee means that the Japanese government was trying to make sure they could produce enough food domestically in case of shortages.
LEE: There were a series of economic crises. There were concerns about self-sufficiency in the context of preparation for war. So all in all, the prominence of flavor in Japanese nutrition research comes from those kinds of concerns.
KWONG: OK, so research in umami was bound up in, like, this broader need for nutrition research that was tied to the economy and what was needed politically at the time.
WEINER: Yeah. Victoria Lee writes about that in her book. It's called "The Arts Of The Microbial World." And speaking of Japanese nationalism, she brought up another possible theory about why Ikeda's work didn't translate, literally. Lee actually told me that it was strategic for some Japanese nutrition researchers to focus on areas that would be specific to or culturally resonant in Japan.
KWONG: What does that mean?
WEINER: Well, for example, Japanese nutrition scientist Suzuki Umetaro - he has a story about going to Germany to work with the famous chemist Emil Fischer. And when he was about to return to Japan...
LEE: Apparently Emil Fischer told him, when you go back to Japan, work on something distinctive to the region like rice. Don't work on what everyone else is working on in Europe because labs in Japan wouldn't be able to compete with the labs in Europe that would be much better equipped.
WEINER: And back in the day, it took a while for scientific papers and materials from Europe to make their way to Japan. So focusing on local resources was one way to get around that.
TRACY: Other reasons that I've come across for why English-speaking scientists weren't compelled by the idea of glutamate representing a fifth taste is, one, just the enormous weight of millennia of tradition. The big four, you know, have had incredible resilience and cross-cultural consensus around those four. So to break with that, anyone would have needed a lot of evidence to overturn that.
KWONG: But the evidence needed to overturn that did come about around the turn of the century. How did American researchers finally begin to embrace umami?
WEINER: So a team at the University of Miami discovered that rats and eventually humans, too, have a specific glutamate receptor both in our brains and our tongues. And that hard biological evidence is what turned the tide.
KWONG: I hear this. And cool as it is, I can't help thinking, Chloee, that Ikeda discovered this a long, long time ago.
WEINER: Yeah. And it took a hundred years and a lot of corporate messaging and efforts from Ajinomoto, Ikeda's company, to work up enough research interest to get there. It's also important to point out that Ajinomoto was very motivated to dissuade the anti-MSG fears in the U.S. because they were hurting the company's bottom line. So shifting the focus to umami both scientifically and also culturally was part of that.
KWONG: That makes sense to me. Like, we like to think of science as independent when, actually, some research is only possible when social forces change, when the historical planets align and people are, like, ready or wanting an idea to be proven even if it was proven a long time ago.
WEINER: Yeah. And it made me think more generally about what other ideas or research is out there that we aren't ready to hear yet.
SHAPIRO: Chloee Weiner and Emily Kwong from NPR's daily science podcast, Short Wave, reporting on the origins of umami.
(SOUNDBITE OF THE CINEMATIC ORCHESTRA'S "THE AWAKENING OF A WOMAN") Transcript provided by NPR, Copyright NPR.
