Mechanism for Perceiving Kokumi Substances: Involvement of Calcium-Sensing Receptor (CaSR) in the Perception of Kokumi Substances

Some foods have sensory attributes, such as continuity, mouthfulness, and thickness, which cannot be explained by the five basic tastes alone. These sensations are elicited by the addition of kokumi substances, which are flavor modifiers that have no taste themselves. However, the underlying mechanisms remain unclear. Investigations on the perception of amino acids and peptides identified γ-glutamyl-cysteinyl-glycine (GSH) as an agonist of the calcium-sensing receptor (CaSR). Therefore, we hypothesized that CaSR may be involved in the perception of kokumi substances. All of the CaSR-activating substances tested herein were effective kokumi substances, and a positive correlation was observed between CaSR activity and the kokumi intensities of γ-glutamyl peptides. Furthermore, the kokumi intensities of GSH and γ-Glu-Val-Gly, a potent kokumi peptide, were significantly reduced by the CaSR inhibitor, NPS-2143. These results suggest the involvement of CaSR in the perception of kokumi substances.