A series of kokumi peptides impart the long-lasting mouthfulness of matured gouda cheese

Comparative sensory analysis revealed that a 44-week-matured Gouda cheese (GC44) exhibited a much more pronounced mouthfulness and long-lasting taste complexity when compared to a young Gouda cheese ripened for only 4 weeks (GC4). To identify the molecules underlying that so-called kokumi sensation, a sensomics approach was applied on the water-soluble extract (WSE44) of GC44 by combining gel permeation chromatography (GPC) with analytical sensory tools. HPLC-MS/MS experiments on GPC fractions inducing a kokumi sensation when tasted in an aqueous biomimetic taste recombinant solution (rWSE44) enabled the identification of 8 α-L-glutamyl and 10 γ-L-glutamyl dipeptides as candidate kokumi-enhancing molecules. Among those, only the γ-L-glutamyl dipeptides were found to impart an enhanced kokumi sensation to the matured cheese, whereas none of the α-glutamyl peptides were found to be active. Among the γ-L-glutamyl peptides, the candidates γ-Glu-Glu, γ-Glu-Gly, γ-Glu-Gln, γ-Glu-Met, γ-Glu-Leu, and γ-Glu-His, present in GC44 in concentrations between 4.11 and 17.66 μmol/kg, were identified for the first time as the key kokumi molecules enhancing mouthfulness and complex taste continuity of the matured cheese.