Analysis of Volatile Compounds and Flavor Fingerprint in Hot-Pressed Flaxseed Oil Processed Under Different Roasting Conditions Using Headspace-Gas Chromatography-Ion Mobility Spectrometry

The variations in flavor compounds of flaxseed oil (FSO) processed under different roasting conditions were studied using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with principal component analysis (PCA). A total of 81 typical target compounds were identified, including 27 aldehydes, 16 ketones, 14 alcohols, 9 heterocycles, 6 esters, 5 acids, 3 hydrocarbons, and one sulfur compound (dimethyl disulfide). After roasting process at 120 °C, 2-propanol, methylpropanal, (E)-2-pentenal, (E)-2-hexenal, and 1-hexanol were the major volatile components, while furfural, 3-(methylthio)propanal, 2-pentanone, 2-heptanone, and 2-ethyl-6-methylpyrazine were the predominant compounds of hot-pressed FSO roasting at 180 °C; (E,E)-2,4-nonadienal, (E)-2-nonenal, propanal, 1-octen-3-one, methyl salicylate, propyl hexanoate, ethyl propanoate-M, and ethyl hexanoate were the main volatile compounds at 240 °C. Additionally, the results of PCA and the Euclidean distance showed the similarity of FSO and its flavor compounds under different roasting conditions. This method could be helpful for the quick and thorough analysis of volatile compounds in FSO. Graphical Abstract