New Taste on the Block

Trader Joe's Umami seasoning

It took a hundred years for a "new" taste, umami, to be acknowledged by food science. [bold added]

In 1907, while enjoying a bowl of soup made with dashi broth and kombu seaweed, the Japanese chemist Kikunae Ikeda had an insight that would change the culinary world. He noticed a taste that wasn’t sweet, salty, sour or bitter.

Ikeda gave this hard-to-describe savory taste a name—umami—and went on to identify the specific amino acid that triggered it.

Scientists in Europe and the U.S. remained skeptical about whether umami really was a taste until a receptor for it was discovered on the tongue almost a century later, in 2000. Today, it is taken for granted by most scientists and chefs...

Now kokumi has come on the scene.

Trader Joe's umami seasoning and
garlic sprinkled on beef ribs:
maybe they'll have kokumi.

The newer taste, kokumi, is even harder to describe than umami, but it is potentially just as important for understanding how and why we enjoy food. In Japanese, the term koku describes foods that have the kind of mouthful “thickness” often imparted by fats—what English speakers might describe as rich. “It feels like a physical sensation,” says the culinary scientist Joshua Evans. It works “by coating the mouth and becoming more intense and being extended in time.” When asked what foods have koku, Japanese food experts list wild boar, adult wasps, duck eggs and aged sake, as well as long-simmered and fermented dishes.

Koku reflects a sensory experience most closely allied with touch, influenced by aromas and textures. Adding the Japanese suffix -mi, meaning taste, highlights the specific taste detected by the tongue. The precise nature of kokumi remains the subject of great debate among sensory scientists and chefs, in part because it can’t be detected on the palate on its own; rather, it modifies other tastes and flavors.

The earliest kokumi research focused on the contribution of garlic to foods. In 1990, Japanese scientist Yoichi Ueda discovered that if he added diluted garlic to two types of soups, people eating them would describe having more sensations associated with kokumi. Subsequent research isolated amino acids in the garlic that seemed to cause the effect, including glutathione.

A Japanese lab claims to have identified the taste receptor triggered by glutathione, and scientists elsewhere have discovered that glutathione and other compounds appear to trigger kokumi in yeasts and in other foods. These include long-cooked meats such as chicken in chicken broth; some cheeses, such as Blue Shropshire, Gouda and Parmesan; and fermented foods like beer, soy sauce and fish paste.

Some sensory scientists remain skeptical. Paul Breslin, a nutritional sciences professor at Rutgers University, contends that the term kokumi will be difficult to understand and use “until the scientific and nonscientific community can agree both on its definition and on the prototypical eliciting stimuli”—that is to say, until we know more.

For all the uncertainty, kokumi has two potentially important implications. The first relates to our understanding of human evolution; the second, human health—especially efforts to create foods with fewer calories but more flavor. In both cases, kokumi may provide a kind of missing link.

Our ancestors didn’t have to be able to give kokumi a name or know its chemical sources to enjoy it. Our own research suggests that one key to the adoption of fire by humans, and the invention and adoption of fermentation, was the flavor of cooked and fermented foods. It is known that humans (as well as dogs, gorillas and chimpanzees) prefer cooked foods over raw foods. Humans also tend to prefer many fermented foods relative to their raw counterparts. But it has long been unclear why.

One possibility is that humans evolved a preference for complex aromas and the experience they contribute to flavor. Uncooked meat and rotten meat that is full of pathogens both tend to have simpler aromas than cooked meat or meat that is fermented and full of beneficial fermentation microbes. It is also notable that cooked meats and fermented foods tend to have kokumi.

We might picture an ancient human ancestor holding up a piece of meat that has been cooked on the fire, pleased by its aromas but also by the rich mouthfeel of its kokumi. Our ancestors didn’t have to be able to give kokumi a name or know its chemical sources to enjoy it.

Chef-researchers employed by top restaurants, such as Nabila Rodríguez Valerón at Copenhagen’s award-winning Alchemist, are now eagerly experimenting with the ways in which kokumi could be featured in modern meals to make foods that taste rich but are low in fat. A recent study by Ciarán Forde at the Clinical Nutrition Research Center in Singapore discovered that if the amino acid associated with kokumi is added to beef broth, particularly in combination with umami flavors, consumers perceive the broth to be richer and to have more calories.

Many traditional recipes from cultures around the world appear to already take advantage of this kokumi effect. For example, adding onion and garlic to soup stock to give it a fuller, deeper flavor. Often recipes start with a step in which chopped onions are soaked in fat or oil, in effect amplifying the flavors of those fats and oils. Kokumi is a taste that asks us to think of food holistically.

At least it's organic

Cooking in fat and oil makes dishes taste better, though traditional food vocabulary--sweeter, saltier, etc.--is inadequate to describe what made the food more enjoyable. Now we know that it was umame and kokumi.

However, I'll probably pass on the wild boar and most definitely the adult wasps. (By the way, how did "Japanese food experts" know that adult wasps are redolent--food critic word--with kokumi?)