Mechanism of The Perception of “Kokumi” Substances

Every food has a unique taste or flavor of its own. But for some, we cannot explain the flavors at all. Neither can they be assigned to the recognized five tastes, nor can we find their exact flavor.

There are few flavor modifiers that enhance the taste of the food. One such taste modifier is kokumi.

 Kokumi substances are those substances that modify the taste of the flavor.

So, I have tried to compile the mechanism of kokumi sensation

Glutathione (GSH) is one of the agonists of the calcium-sensing receptor(CaSR). Hence, it is the base of the overall mechanism. A positive correlation exists between the CaSR activity of glutamyl peptides and kokumi intensity.

The kokumi intensity of GSH and glutathione, valine, and glycine, which is potent kokumi peptide reduced by the CaSR specific antagonist.

CaSR is involved in the perception of kokumi substances. And the glue-Val-gly is a kokumi peptide and would be useful for improving the flavor of food.

The mechanism of the perception of kokumi substances and the sensory characteristics of the potent kokumi peptide, γ-Glu-Val-Gly is as follows

All CaSR agonists tested, such as Ca²⁺, protamine, polylysine, L-histidine, and γ-glutamyl peptides enhanced the taste intensity of umami-salty solutions. Second, since GSH (γ-Glu-Cys-Gly) is a potent kokumi substance, various γ-glutamyl peptides, such as γ-Glu-Ala, γ-Glu-Val, γ-Glu-Cys, γ-Glu-Abu-Gly (Abu means α-aminobutyric acid) and γ-Glu-Val-Gly were synthesized.

The kokumi intensity of γ-Glu-Val-Gly is measured by the point of substantial equivalent (PSE) method. The sensory evaluation demonstrated that the solution of γ-Glu-Val-Gly produced a kokumi equivalent to a GSH solution. Therefore, it is estimated that the kokumi intensity of γ-Glu-Val-Gly is stronger than that of GSH.

As results of the sensory evaluation with the trained panelists, the addition of Glu-Val-Gly significantly enhanced the intensity of sweetness, saltiness and umami.