Characterisation of the key aroma compounds in commercial native cold-pressed rapeseed oil by means of the Sensomics approach

A systematic approach for the characterisation of the most important aroma-active compounds in a commercial native cold-pressed rapeseed oil on the basis of the Molecular Sensory Science Concept, consisting of aroma extract dilution analysis (AEDA), identification experiments by gas chromatography-olfactometry and gas chromatography-mass spectrometry, stable isotope dilution analysis (SIDA), calculation of odour activity values (OAVs), and recombination experiments, was performed. Forty-nine aroma-active compounds, isolated by thin layer distillation, were identified with a flavour dilution factor a parts per thousand yen8 during AEDA and headspace AEDA, 23 thereof reported in native cold-pressed rapeseed oil for the first time. Twenty-three odorants were quantitated via SIDA revealing for 11 compounds concentrations above their respective odour thresholds. Thereby, 2-isopropyl-3-methoxypyrazine, dimethyl trisulphide, dimethyl sulphide, butanoic acid, and octanal showed the highest OAVs (ratio of concentration divided by respective odour threshold). For data validation, a reconstitution model was prepared by mixing the odorants in their natural occurring concentrations in an odourless oily matrix showing an aroma profile very similar to the profile of the original rapeseed oil, confirming that all key aroma compounds were identified and quantitated successfully.