Discovery of taste modulating octadecadien-12-ynoic acids in golden chanterelles (Cantharellus cibarius)

Activity-guided fractionation in combination with taste dilution and comparative taste dilution analysis, followed by LC-MS and 1D/2D-NMR experiments, enabled the identification of several C18-acetylenic acids in chanterelles among which (9Z,15E)-14,17,18-trihydroxy-9,15-octadecadien-12-ynoic acid, (9Z,15E)-14-oxo-9,15-octadecadien-12-ynoic acid, (10E,15E)-9-hydroxy-14-oxo-10,15-octadecadien-12-ynoic acid, (10E,15E)-9-hydroperoxy-14-oxo-10,15-octadecadien-12-ynoic acid, (10E,15E)-9,14-dioxo-10,15-octadecadien-12-ynoic acid, (9Z,15E)-14-oxo-9,15-octadecadien-12-ynoic acid methyl ester, (9Z,15E)-17(18)-epoxy-14-oxo-9,15-octadecadien-12-ynoic acid methyl ester and (10E,14Z)-9-hydroperoxy-10,14-octadecadien-12-ynoic acid have not yet been reported in literature. Sensory evaluation in a basic taste recombinant revealed taste modulating thresholds for the octadecadien-12-ynoic acids in the range of 19-105 µmol/l. In comparison, three isolated octadecadienoic acids, namely (10E,14Z)-12-hydroxy-10,14-octadecadienoic acid, (9Z,11Z)-14,18-dihydroxy-9,11-octadecadienoic acid, and (9Z,11Z)-14,17,18-trihydroxy-9,11-octadecadienoic acid, respectively, did not show any taste modulating activity, thus pinpointing the putative key role of the acetylene moiety for kokumi enhancement.