Umami and “koku” sensations key to breaking taste barriers in plant-based diets, flags research

Unearthing the science behind meaty tastes and textures could influence more people to switch to plant-based diets, according to recent research compiled in a book titled Plant-Forward Cuisine.

“The book argues, based on fundamental plant biology and human evolution, that the fifth basic taste umami is typically absent in plants, e.g., vegetables (apart from some ripe fruits). But it is our genetic inheritance to seek out umami-rich foods,” co-author Ole G. Mouritsen, professor Emeritus of Design and Consumer Behavior at the University of Copenhagen, Denmark, tells Food Ingredients First.

Plant-Forward Cuisine is written by Mouritsen, chef Klavs Styrbæk, and translator Mariela Johansen. The authors note that umami is an often overlooked taste in the much more common sweet, salty, sour, and bitter flavors.

In addition to umami, “koku,” which is a sensation Japanese researchers associate with food that feels “mouthful, rich and continuous,” could be a “game-changer” for people wanting to include plant-based foods in their diet but struggling with taste, Mouritsen suggests.

Decoding umami and “koku” flavors

According to the book, the key to umami tastes is free glutamate and nucleotides, which are commonly found in animal products but rarely in plants. Some fruits, such as sun-ripened tomatoes, mushrooms, and certain seaweeds, can feature this taste.

“This is why most people have difficulties consuming 500-600 g of greens every day. Once you understand this conflict, there is also an immediate solution. Add umami to your plant-rich foods or release the built-in umami potential of plants through fermentation. The crucial point is that even if we are accustomed to getting umami from animal-based foods, like meat, it is not meat we crave but the taste of meat,” Mouritsen tells us.

The authors explain that the science behind “koku” has more to do with small proteins called dipeptides and tripeptides, which evoke the signature sensation. Dipeptides are known for being present in umami-tasting foods and are especially active in fermented foods and cheeses like gouda and parmesan.

On the other hand, “koku” sensations are created when tripeptides (a molecule consisting of three amino acids linked together) interact with the calcium channels on the tongue’s surface. Glutathione types are prominent within these tripeptides, which, even in small amounts, can create “koku.”

Garlic, chicken, beef, shrimp paste, fish sauce, scallops, soy sauce, and beer carry glutathione.

A flexitarian approach

Meanwhile, the authors note that an entirely vegetarian or plant-based diet is unnecessary, suggesting that a flexitarian approach, defined by a plant-forward diet with occasional meat intake for a taste of umami flavors, can prove a more enduring alternative.

Fermentation techniques can be promising for incorporating umami and koku into large-scale plant-based product development.“Small quantities of meat, fish, shellfish, mollusks, and roe can greatly affect and play a supporting role in making a dish more appealing.”

According to Mouritsen, certain innovations can be promising for incorporating umami and koku into large-scale plant-based product development within the F&B industry. These include “the development of umami-rich condiments and seasonings, as well as novel fermentation techniques.”

“The flavor accelerators described in the book provide model examples.” These include miso mayonnaise, hoisin sauce, and toasted nuts.

When asked whether plant-forward cuisines can be adapted to culinary traditions where animal proteins are deeply ingrained in daily diets, Mouritsen suggests that proteins “are specifically not the issue.”

“There is no lack of protein in the world, and most people get the protein they need. It is the taste of free amino acids from proteins, together with the free nucleotides from meat, seafood, fungi, and alga, that are crucial. The solution is the so-called flavor enhancers (natural products, simple preparations) that can readily be used to umamify plant-based foods.”

Additionally, he notes that there are no gaps in current flavor science that need to be addressed to replicate the complexity of meaty tastes and textures. “It is more a matter of using the existing knowledge.”

F&B brands can tap into umami-and koku-rich plant-based products while remaining resource-efficient, Mourtisen says.

“By understanding where umami and koku attributes come from, it is possible to cut down on food waste and eat sustainably without compromising taste. There is a need to develop umami-rich beverages that complement food with only a little umami.”