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By application of a comparative aroma extract dilution analysis on the volatile fractions isolated by solvent extraction and solvent-assisted flavor evaporation (SAFE) from fresh raw Chinese ginger ( Zingiber officinale Roscoe ) and roasted ginger, 21 or 33 odorants, respectively, with flavor dilution (FD) factors in the range of 32-4096 were identified. In raw ginger, the highest FD factors were found for ( E )-isoeugenol, 1,8-cineol, vanillin, geranial, and linalool. After roasting, in particular, the FD factors of 3-(methylthio)propanal (cooked potato-like), 4-hydroxy-2,5-dimethyl-3(2 H )-furanone (caramel-like), 3-hydroxy-4,5-dimethyl-2(5 H )-furanone (seasoning-like), and geraniol were substantially increased. The application of static headspace/olfactometry (SHO) on ground raw ginger revealed a high FD factor for highly volatile acetaldehyde which clearly decreased after roasting. By contrast, the SHO application revealed high FD factors for malty smelling methylpropanal and 3-methylbutanal, which both were exclusively detected in roasted ginger. Thirteen odorants, namely, decanoic acid, ( Z )-2-decenal, ( Z )-4-decenal, ( E )-4,5-epoxy-( E )-2-decenal, ( E )-4,5-epoxy-( E )-2-undecenal, fenchol, ( Z )-3-hexenal, 3-hydroxy-4,5-dimethyl-2(5 H )-furanone, 4-hydroxy-2,5-dimethyl-3(2 H )-furanone, 3-methyl-2-buten-1-thiol, 2-methylpropanal, ( E )-2-nonenal, and 1-nonen-3-one, were identified in ginger for the first time. Chiral analysis showed a much higher percent by weight portion for the ( R )-enantiomer in citronellal, citronellol, and linalool, which was not much changed during pan-frying.

Twenty key odorants recently identified in raw and roasted ginger were quantitated by means of stable isotope dilution assays, of which six assays were newly developed. Odor activity values (OAV; ratio of concentration to odor threshold) revealed 1,8-cineol (eucalyptus-like) with by far the highest value of 65 000 followed by myrcene (geranium-like), for which an OAV of 19 000 was calculated. In addition, ( R )-citronellal, geranial, ( R )-linalool, ( E )-isoeugenol, and ( E )-2-octenal contributed with high OAVs to the overall aroma profile of the fresh, raw ginger. An aroma recombinate prepared with 20 reference compounds in the same concentrations as determined in the ginger sample successfully matched the overall aroma profile. In the roasted ginger, 1,8-cineol and myrcene remained the most odor-active compounds, however, the increase in some odorants, for example, in geraniol and ( Z )-2-decenal, in combination with the newly formed caramel-like smelling 4-hydroxy-2,5-dimethyl-3(2 H )-furanone (caramel-like) and 3-(methylthio)propanal (potato-like) most likely caused the differences in the aroma profile initiated by the thermal treatment. A biomimetic aroma recombinate based on 21 aroma compounds was able to successfully simulate the aroma profile of the roasted ginger.