Key Odorant Identification Confirms 3-Oxododecanal as the Most Important Contributor to the Characteristic Aroma of Fresh Rhizomes and Leaves of Houttuynia cordata

Houttuynia cordata is an Asian culinary herb with a characteristic fishy aroma. The most odor-active compounds, which had previously been identified by a comparative aroma extract dilution analysis applied to fresh rhizomes and leaves, were quantitated by GC–MS or GC–FID. Results revealed 23 and 22 compounds with odor activity values (OAVs) > 1, i.e., their concentrations exceeded their odor threshold concentrations, in rhizomes and leaves, respectively. Of these, myrcene (geranium leaf-like) and 3-oxododecanal (metallic, soapy, fishy) showed the highest OAVs. Aroma reconstitution and omission tests revealed that 3-oxododecanal is key to the characteristic fishy note. Results on the effect of tissue disruption suggested that 3-oxododecanal was already present in the intact H. cordata plant and released upon mechanical impact.