Exploring the molecularity of spices: the gustatory perspective

Abstract We explored the electronic-structural features of molecules that elicit specific spice-taste responses. The purpose of this work was to identify reproducible molecular fingerprints that contribute to these specific tastes and flavors. Our work informs us that these fingerprints go beyond gross molecular features such as aliphatic or aromatic systems, straight chains or rings, and specific functional groups. We explored these molecules down to the granularity of atom-pairs in structurally and chemically disparate molecules that produce the same response. The atoms in the atom-pairs were bonded and remote. The electronic features were represented by Nuclear Magnetic Resonance (NMR) chemical shifts, which depict the electronic and chemical environments around an atom in the atom-pair. The structural features were represented by interatomic (bonded or non-bonded) distances. We explored these fingerprints for 34 molecules whose tastes and flavors were identified by taste experts. We identified atom-pairs that are likely responsible for specific spice-related flavors: spicy, herbal, woody, citrus, sweet, and minty, or combinations of these flavors. For molecules clustered by similar flavors, our results are consistent and independent of the overall structural and chemical nature of the molecule. This innovative methodology identifies the molecularity of the nuances of spice flavors.