Tasting umami with all five senses: Lecture on “Dashi” and “Umami” at Tohoku University
November 2024
On November 21, the Umami Information Center (UIC) held a lecture titled “‘Dashi’ and ‘Umami’” at Tohoku University.
This lecture was a part of the university's regular course, “Basic Seminar: Understanding Japanese Food Culture Scientifically.” This 15-session seminar is taught by lecturers from outside organizations such as companies and other universities, in addition to professors from Tohoku University. Professor Nobuyuki Sakai of Tohoku University, who is a professor of the Faculty of Letters and the Vice Chairman of UIC, organizes the entire program. Director Yasue Kido of UIC provided the eighth lecture, which was the midpoint of the program.
Director Kido structured her lecture intending to stimulate the students' intellectual curiosity and make them want to learn more about umami in a scientific way.
She focused on dashi, a common umami food and an indispensable ingredient in washoku and designed her lecture to encourage students to think more deeply about umami, which is closely related to dashi.
In the classroom, actual kombu, katsuobushi (dried bonito flakes), niboshi (dried sardines), and dried shiitake mushrooms were displayed. These are typical dashi ingredients.
Students observed them by touching and smelling them, and actually made four types of dashi in the classroom. They carefully tasted the four types of dashi to understand three properties of umami: “Spreads across the tongue, coating it,” “Lingers longer than other tastes,” and “Promotes salivation.
Then they experienced the “umami synergy effect” that occurs when glutamate, an amino acid-based umami component, is combined with inosinate or guanylate, nucleic acid-based umami components, using kombu dashi, katsuo dashi & niboshi dashi and dried shiitake mushroom dashi. And they worked on expressing the characteristics of each dashi they sensed, in their own words.
In the latter half of the training, the students tried making their favorite miso soup using a combination of two different types of miso; Sendai miso and Hatcho miso, and the four types of dashi. The students also experienced the health benefits of umami by making salted cucumbers and wrote down their impressions of how umami makes food taste better even with less salt.
This intensive course was attended by students from various faculties, including the Faculty of Pharmacy, Education, Agriculture, Medicine, Science, and the Faculty of Letters and Science.
They worked diligently and happily on their assignments, sharpening their senses and feeling the smell, taste, and retronasal aroma ※ in order to describe dashi and umami in their own words.
※ retronasal aroma：The aroma that is felt when you put food in your mouth and chew or drink it, and the aroma components pass from the back of your throat to your nose.
The feedbacks from the students showed the impressions that were unique to each faculty. Some of them are introduced below.
・Great to taste dried shiitake mushroom dashi for the first time. It was a familiar taste. (Agriculture)
・I want to know more about the chemical reactions of umami substances. (Pharmacy)
・Interested in the difference between the words “dashi wo toru” and “dashi wo hiku,” which have almost the same meaning in everyday Japanese. (Literature).
・It was a good experience to learn umami not only by listening to knowledge but also by experiencing it through practical training.(Education)
・I want to know scientifically the temperature at which umami substances are most produced and the reasons why (Science)
・Surprised by the fact that umami makes food taste better, even with less salt (School of Medicine)
“It was good to learn how to make dashi and to compare single taste of the different types of dashi” was a common feedback from many students from all faculties.
We believe that this lecture was a good opportunity for them to think deeply about dashi and umami as everyday foods. Here is one of their answers to the the question, “How and to whom would you like to convey the goodness of dashi and umami?”
“I would like to convey the goodness of dashi and umami to those who are not satisfied with their daily diet. Dashi gives us a sense of fulfillment because its aroma and umami taste remain in our mouths for a long time. In this age of food satiety, this sense of fulfillment is a precious quality of dashi and umami.”
We learned a lot from the young people's words.
We hope that they will make use of the benefits of dashi and umami in their daily lives and pass them on to those around them.