Flavornet and human odor space

by Terry Acree & Heinrich Arn

Gas chromatography - olfactometry (GCO) of natural products
Sponsored by DATU Inc.
There are 738 odorants listed as of 6.25.04


Flavornet is a compilation of aroma compounds found in human odor space. A seemingly infinite number of perceptions are invoked by less than 1000 odorants that make up this space. These chemicals with mass less than 300 Daltons bind to proteins on the olfactory receptor neurons (ORNs) at the surface of the olfactory epithelium. Excitation of ORNs generates a topographic map of sensory information in the brain that is a representation of the stimulating chemical features of the external world. The Flavornet lists only those odorants that have been found in a human odor space at supra-threshold levels i.e. at levels likely to stimulate ORNs.

In Flavornet odorants are arranged by chromatographic and sensory properties. Except for indexing standards the data have been taken from published research using GCO. They are listed by retention indices both Kovats n-paraffin and ethyl ester on four different substrates. A link to a summary page containing chemical properties, sensory descriptors, bibliographies and pdb (protein data bank) files of MM2 minimized structures is provided for each ligand. To be included in Flavornet an odorant must have been detected in a natural product or real environment by some form of quantitative GCO method e.g. dilution analysis (Aroma Extraction Dilution Analysis or CharmAnalysis™) perceived intensity analysis (e.g. Osme) or detection frequency analysis (e.g. SNIFF). Therefore, the Flavornet lists only those volatiles that humans use in their chemical ecology. Once on the list, missing data about an odorant was filled in with estimates (shown in square brackets). These estimates will be replaced with experimental measurements as they become available. In every case data from the first report of a GCO detection will be used unless a more accurate report is subsequently made, then, the new data will be included along with the original.

The present data was collected from articles published since 1984 using GCO to detect odorants in natural products. In the summers of 2003 and 2004 Hannah E. Collins, Yale University, read over 100 of these articles and checked the chemical data for the odorants against the Chemical Abstract Service databases.

If you are willing to add to this data base contact Terry Acree with the citation where the data is published or if the source is difficult to obtain send a copy of the paper to:

Terry E. Acree
Cornell University
Geneva, NY 14456 USA

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