Effects of different extraction methods on volatile profiles of flaxseed oils

To investigate the effects of different extraction methods on volatile compounds in flaxseed oil (FSO),
we first carried out solvent extraction, cold pressing, and hot pressing treatments of flaxseed [Linum
usitatissimum (L.)], then applied the headspace-gas chromatography-ion mobility spectrometry
technology to identify the volatile substance compositions, and established flavor fingerprints of
solvent-extracted FSO, cold-pressed FSO, and hot-pressed FSO. In total, 81 volatile compounds were
detected, including 27 aldehydes, 14 alcohols, 13 ketones, 9 heterocycles, 8 esters, 5 acids, 4
hydrocarbons, and 1 sulfur compound (dimethyl disulfide). Extraction methods had a great influence on
the volatile profile of FSO. Solvent-extracted FSO had more sweet, mild, floral, and sour volatile profiles,
cold-pressed FSO had stronger volatile profiles of winey, spicy, and fatty, and hot-pressed FSO had
green, grass, and plastic volatile profiles. Principal component analysis and Euclidean distance
demonstrated that the volatile compounds of three FSO samples could be clearly distinguished. Of note,
the cold-pressed FSO and hot-pressed FSO had similar volatile profiles, and they were different from
solvent-extracted FSO. This study could provide some guidance for improving the flavor quality of FSO
and selecting the proper extraction method for FSO productions. PRACTICAL APPLICATION: Practical
Application: This study shows extraction methods significantly affect the formation of aroma characteristics in flaxseed oil (FSO), and it provides theoretical guidance for production to use the
appropriate extraction methods for high-quality FSO.