Characterization of Key Odorants Causing a Fusty/Musty Off-Flavor in Native Cold-Pressed Rapeseed Oil by Means of the Sensomics Approach

The sensomics approach was used to clarify the formation of the fusty/musty off-flavor of native cold-pressed rapeseed oil. A positive control (PC) showing the desired sensory attributes and an oil eliciting a fusty/musty off-flavor (OF) were analyzed. Comparative aroma extract dilution analysis (cAEDA), identification experiments, quantitation by stable isotope dilution assays (SIDAs), calculation of odor activity values (OAVs), and aroma recombination resulted in 11 odorants with an OAV >= 1 in PC. Main differences between both oils were obtained for compounds caused by microbial influence revealing significantly higher concentrations in OF, e.g., for ethyl 2-methylbutanoate, 2-methoxyphenol, 3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolon), 2- and 3-methylbutanoic acid, and 4-methylphenol. Comparison of the key odorants in OF with those of the rapeseeds (OFS), from which it was pressed, showed the same 18 compounds proving that the grade of the seeds and their storage conditions are important criteria for the quality of the final oil. Finally, a further 7 native cold-pressed rapeseed oils, eliciting the same sensory defect, were analyzed to confirm aroma-active marker compounds responsible for the fusty/musty off flavor.