Structural and Sensory Characterization of Key Pungent and Tingling Compounds from Black Pepper (<i>Piper nigrum</i> L.)

To gain a more comprehensive knowledge on whether, besides the well-known piperine, other compounds are responsible for the pungent and tingling oral impression imparted by black pepper, an ethanol extract prepared from black pepper (<i>Piper nigrum</i> L.) was screened for its key sensory-active nonvolatiles by application of taste dilution analysis (TDA). Purification of the compounds perceived with the highest sensory impact, followed by LC-MS and 1D/2D NMR experiments as well as synthesis, led to the structure determination of 25 key pungent and tingling phytochemicals, among which the eight amides 1-(octadeca-2<i>E</i>,4<i>E</i>,13<i>Z</i>-trienyl)­piperidine, 1-(octadeca-2<i>E</i>,4<i>E</i>,13<i>Z</i>-trienyl)­pyrrolidine, (2<i>E</i>,4<i>E</i>,13<i>Z</i>)-<i>N</i>-isobutyl-octadeca-2,4,13-trienamide, 1-(octadeca-2<i>E</i>,4<i>E</i>,12<i>Z</i>-trienoyl)-pyrrolidine, 1-(eicosa-2<i>E</i>,4<i>E</i>,15<i>Z</i>-trienyl)­piperidine, 1-(eicosa-2<i>E</i>,4<i>E</i>,15<i>Z</i>-trienyl)­pyrrolidine, (2<i>E</i>,4<i>E</i>,15<i>Z</i>)-<i>N</i>-isobutyl-eicosa-2,4,15-trienamide, and 1-(eicosa-2<i>E</i>,4<i>E</i>,14<i>Z</i>-trienoyl)-pyrrolidine were not yet reported in literature. Sensory studies by means of a modified half-tongue test revealed recognition thresholds ranging from 3.0 to 1150.2 nmol/cm<sup>2</sup> for pungency and from 520.6 to 2162.1 nmol/cm<sup>2</sup> for the tingling orosensation depending on their chemical structure.