[Feature: The Future of Japanese "Food"] Ryuichi Suzuki: The Power of Japanese Cuisine Brought Out by AI Taste Sensors

I serve as the representative of a company called AISSY, which has developed and commercialized "Leo," a taste sensor capable of breaking down and quantifying the flavors of all foods and drinks into five basic tastes (sweetness, saltiness, sourness, bitterness, and umami). AISSY is a company founded based on research results from Keio University, with investment from Keio. The company name is an abbreviation for Artificial Intelligence SensingSYstems, but it also carries a second meaning—"I see"—reflecting our mission to visualize the invisible (taste).

Through various analyses with Leo, I feel I have begun to see a bright future for Japan through food. Here, I would like to introduce taste sensor technology and then write about the potential of Japanese cuisine.

The roots of Leo go back to my days as an undergraduate at Keio. When I was a sophomore, there was a ramen shop near the Hiyoshi Campus that, frankly, wasn't very good. It was the kind of place where only about five customers would come in a day. Due to certain circumstances, I ended up helping manage that ramen shop with a few friends from Keio, but the discussions we had about taste were extremely difficult. Being a science student, I liked discussing things using numbers even back then, but numbers never came up in conversations about taste. The discussions were entirely qualitative, consisting of things like "let's reduce the salt a bit more" or "let's add this topping to bring out a little more umami." At that time, I felt a potential need to quantify taste.

Later, as a senior, I saw my academic advisor at the time, Professor Koji Suzuki, and my seniors researching the technology that would become the basis for the current Leo, and it connected with my experience at the ramen shop. I figured that food and beverage manufacturers must be discussing taste even more than I did at the ramen shop, so there had to be customers who wanted to quantify it. Taste sensors did exist back then, but they faced challenges such as the inability to measure sweetness and low accuracy due to linear analysis methods.

The AI taste sensor developed at Keio was a groundbreaking technological seed that solved the problems of previous taste sensors. I felt it had a strong chance of success as a business, so I founded AISSY immediately after completing graduate school.

At AISSY, we conducted joint research with Keio University and developed a technology capable of sensing the five tastes humans perceive (sweetness, saltiness, sourness, bitterness, and umami). We achieved this by using an analysis method called neural network analysis, which accounts for taste interactions, on the component concentrations detected by electrochemical sensors. Figure 1 shows the conceptual diagram and error comparison of the taste sensor (the small error indicates that it can reproduce human taste). Neural networks are the fundamental concept behind the AI that is currently booming.

In product development, Leo is often used to determine how to get closer to a target taste. In marketing, many client companies increase sales by highlighting high levels of sweetness or umami. If you are interested, please visit this site.

As I researched taste, I began to think that the Japanese sense of taste is miraculous, and I even published a book titled "The Japanese Sense of Taste is the Best in the World" (Kosaido Shinsho).

In a word, the greatness of the Japanese sense of taste is the sensitivity to umami. As shown in Figure 2, results from Leo's research show that when comparing Japanese food on average, it has a much stronger umami profile than food from overseas. The true identity of that feeling of "something is missing, I miss Japanese food" when going abroad is "umami."

So, why did we develop a food culture that perceives umami so strongly? It relates to Japan's geographical factors as an island nation surrounded by the sea. You might think the UK is the same, but while the fish caught in the UK don't have much variety, Japan is not only surrounded by the sea but has a long coastline and sits at the intersection of northern and southern currents. Thus, it is blessed with seafood and abundant marine resources.

To begin with, for a country or region to grow to a population of over 10 million, it is essential to consume animal protein. Populations grow by eating meat and fish, but because fish yields fluctuate much more wildly than meat, fish was relegated to the position of a meat substitute in other regions. However, during the Edo period, Japan was able to provide animal protein for a population of 20 to 30 million almost entirely through fish. While obtaining animal protein from seafood, the culture of dashi (broth), such as bonito dashi and kelp dashi, became highly developed. This is why Japanese food is rich in umami.

Additionally, Japanese people cultivated their sense of sweetness through white rice. Compared to the sweetness of sugar, the more you chew white rice, the more sweetness comes out. This led people to savor flavors more carefully, and their taste receptors naturally became sharper.

Southeastern China had an environment close to Japan's, and in fact, the prototype of sushi was born there. Animal protein is difficult to preserve for long periods, and the solution was to preserve fish by putting it in cooked rice. The rice fermented naturally, and the lactic acid produced during that process prevented the fish from spoiling. This was transmitted to Japan and became sushi. However, on the continent, it is said to have been phased out due to the meat-oriented thinking of ethnic groups that later came from inland.

Food is a culture, so it develops and it also declines. To develop, new combinations are necessary. For example, Nikujaga (meat and potato stew), which is commonplace today, uses Western ingredients with Japanese seasoning, so it was an impossible combination until the Meiji era. Eventually, it gained public acceptance and spread.

Taste also changes with the times. Recently, Japanese people have become accustomed to the bitterness of coffee. Originally, that kind of sharp bitterness did not exist in Japan. Certainly, tea has bitterness, but while tea is bitterness + umami, coffee is bitterness + sourness, resulting in a sharp bitterness. It's easy to understand if you imagine Italian cuisine; in Western cooking, the combination of sourness and umami is popular, whereas in Japanese food, the combination of saltiness and umami is orthodox.

Today, taste is becoming globalized, and the tastes of different countries are not as distinct as they once were. In recent years, the preference for umami has been rising worldwide, and the whole world is becoming "umami lovers," which is a huge opportunity for umami-rich Japanese food. By exporting the rare sense of taste and food culture of the Japanese—born from an exquisite distance from the continent—to the rest of the world, Japan's future will become brighter as its food spreads further.

In doing so, it will be important to arrange it in a way that is easily accepted locally, just like the aforementioned Nikujaga. Humans are wary of "tastes that are too new" and get bored with "the usual taste," so a "slightly new taste" is best. I want to make it possible to discuss how to achieve a "slightly new taste" quantitatively using taste data. It is theoretically possible to quantify the taste of local cuisine and use AI to learn and calculate what kind of taste will be accepted, so all that's left is to create success stories.

The future of realizing "product development based on scientific data, not just intuition," which I felt during my days as a Keio student challenging the reconstruction of a ramen shop, is just around the corner.