Quantitation of Key Aroma Compounds in Fresh, Raw Ginger (Zingiber officinale Roscoe) from China and Roasted Ginger by Stable Isotope Dilution Assays and Aroma Profiling by Recombination Experiments

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(2H)-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.