Umami & Kokumi

The umami taste was first scientifically identified in 1908 by Kikunae Ikeda, a professor from the Tokyo Imperial University. He noticed that the taste of kombu soup stock was distinct from sweet, sour, bitter, and salty. He named it umami. Umami is the taste of “savoriness”. It is from the Japanese word “umai” meaning delicious or palatable and is represented by a mouth-watering sensation. It is generally associated with meaty, brothy flavors, although it can be found in many different types of food.

The umami taste can be delivered by foods such as shellfish, cured meats, mushrooms, ripe tomatoes, seaweed, or any fermented or aged products. Parmesan cheese and soy sauce are some examples.

What is the common denominator to all those foods? All the mentioned foods are naturally rich in savory substances, such as inosine-5’-monophosphate (IMP) and guanylo-5’-monophosphate (GMP). These naturally occurring substances are responsible for eliciting salivary secretion. They enhance appetite and increase food palatability, thus making the food delicious!

Kokumi, instead of being a separate taste, is more like a sensation that combines primary tastes and physical properties (e.g., viscosity). In Japan, “koku” has long been used as a sensory attribute to describe the delicious mouthfeel of food, while the term “kokumi” was coined to denote koku and the compounds that can elicit it (these compounds are known as kokumi substances). Kokumi substances usually have no inherent taste; if they do, the taste is faint. However, the addition of kokumi compounds may modify the intensity of other basic tastes, to contribute to a fuller, more complex, long-lasting flavor in foods.

Kokumi-active peptides, which are distributed in many kinds of foods, induce a rich and long-lasting mouthfeel. In 1990, Japanese researchers noticed that adding water extract of garlic could make soup taste fuller and richer. This complicated flavor could not be explained by any of the five basic tastes. Therefore, it was defined as a sensation. The “kokumi sensation” was mainly composed of three characteristics: thickness, mouthfulness and continuity. Kokumi sensations can be caused by several compounds, such as peptides, calcium, protamine, glutathione and L-histidine.