The colour of Umami
History has shown that many discoveries occurred unintentionally. The same applies sometimes also to great recipes!
It was a rainy and cold evening in February. I was sitting in front of my kitchen window observing the raindrops splashing on the road when hunger knocked on my door. I felt cooking something ‘homey’, comfort and easy. I looked at my kitchen shelves and my eyes locked on a glass jar semi-filled with traxana, a traditional Greek dried pasta made from whole wheat or flour and fresh or sour milk (mine was a mix of durum wheat semolina and sheep’s milk).
Traxanas is typically cooked in water to a porridge consistency as a result of starch released into the medium, in a similar manner as the cooking of risotto. It is simply served with some feta cheese and eaten as such, at least as the basic recipe, that I knew from childhood, denotes. On that evening, I thought to deviate from the classic way and decided to combine it with dried porcini mushrooms. I thought also to finish before catching molds the remaining of some tomato paste lying already for days in the fridge. Traxanas cooks fast and soon after I plated it, I sat at the table and put the first bite into my mouth. I experienced a divine taste that spread all over my tongue and made me feel keeping the food in the mouth for a long time. I simply did not want to swallow it. The more it stayed in the mouth, the more intense the flavour was getting and more saliva was coming out from my salivary glands. I said then to myself “this should be the taste of umami!”.
Umami is a Japanese word that refers to something that has a savoury and pleasant taste, something that simply tastes delicious. Nowadays, it is one of the five basic taste profiles of foods, together with salty, sour, bitter and sweet. However, its recognition as a distinct taste delayed for almost a century. Everything started in 1908, when the curiosity of Kikunae Ikeda, a Japanese chemist, led him to investigate the responsible component for the unique taste of a basic preparation in Japanese cuisine, namely the soup stock Dashi that is prepared by boiling dried Kombu seaweed. Kikunae had experienced the same taste in tomato, asparagus, cheese and meat during his stay in Germany few years earlier. He performed a chemical analysis and identified glutamic acid (glutamate) salts to give that taste to Dashi. He named the taste Umami.
A few years later, Shintaro Kodama followed Ikeda’s ideas and discovered another compound (5’-inositate) delivering the umami flavor in dried Bonito that is also used to make Dashi. In 1957, Akira Kuninaka demonstrated that a similar compound (5’-guanylate) is responsible for the umami character in dried Shiitake mushrooms. Importantly, he also proposed that the combination of the aforementioned compounds creates a synergy and enhances substantially the “Umami effect” (1).
Since then, it took decades of discussions and debates on whether umami should be accepted as a unique taste. A milestone that significantly constituted umami as such was the discovery of specific receptors all over onto our taste buds. The umami carriers bind those receptors inducing signal transduction, followed by taste sensation (2).
Umami in foods
The umami carriers, particularly glutamate, are found in a great variety of foods, like vegetables, meat, cheese, fish, beans, mushrooms, seaweeds, dairy products, even in tea. However, their concentration is much higher in dried, cured and preserved foods (3), due to concentrated flavour and/or glutamate release after protein degradation.
Among vegetables, tomatoes rank first in glutamate content, something that is not a surprise considering their worldwide popularity. Ripening enhances furthermore glutamate production, while drying can concentrate flavour up to five times. Dried tomatoes are on the very top of the umami food list, not only due to high glutamate but because they have additionally detectable amounts of guanylate, thus a synergistic potential.
Foods packed with glutamate are also the Kombu and Nori seaweeds, followed by fermented soy sauce and cheeses aged for a long time, like Parmigiano-Reggiano.
High amounts of inositate are found in dried fish, particularly in bonito tuna and sardines/anchovies. Guanylate, on the other hand, is abundant in dried shiitake mushrooms.
In retrospect, what I experienced that evening eating the traxana dish was probably the synergistic umami effect. Even though I could not find any data on porcini mushrooms, I strongly believe they contain high amounts of guanylate as the shiitake. The combination with tomato paste, which is concentrated tomato and thus glutamate, creates a synergistic effect that made my taste buds super happy. On top of that, it came the sour note from traxanas to give an extra dimension to the dish.
It passed already a week from that evening and I still remember that taste…I think I will never forget it!
Traxanas with dried porcini and tomato paste
(Approximate amounts for two portions)
20g dried porcini soaked in hot water, plus this water
a tablespoon of tomato paste
extra virgin olive oil
hot water or a basic vegetable broth
- Start by soaking the porcini in hot water for an hour.
- Chop thinly the onion and sauté in a pan with extra virgin olive oil, in medium heat for a couple of minutes, until it gets translucent.
- Add the traxana and toast for another minute.
- Add the tomato paste and importantly mix it and cook it also for a minute, until it darkens in colour, releases the aroma and starts sticking on the pan. Mix constantly with a spatula to prevent burning.
- Add the porcini water plus the soaked mushrooms.
- Cook using the risotto technique by adding extra hot water or vegetable broth when needed. Stir frequently because traxanas sticks easily on the pan.
- Traxanas needs approximately 10-15 min to cook. Test doneness and finish keeping the mix to a porridge consistency.
- Serve and sprinkle with finely chopped rosemary. Drizzle with some extra virgin olive oil and enjoy the taste and colour of umami!
(1) Ninomiya K. Science of umami taste: adaptation to gastronomic culture. Flavor (2015), 4:13
(2) Li X, Staszewske L, Xu H, Durick K, Zoller M, Adler E. Human receptors for sweet and umami taste. Proc Natl Acad Sci USA (2002), 99:4292