Lipidomics reveals the formation of key aroma compounds in flaxseed oil during seed roasting

Abstract

The lipid profile of flaxseed, particularly in relation to flavor generation in hot-pressed oils, has not been widely reported. Therefore, this study aimed to establish correlations between identified lipid markers and key aroma compounds to investigate potential lipid precursors of flaxseed oil (FSO) flavors. In total, 94 volatile compounds were detected using headspace solid-phase microextraction gas chromatography-mass spectrometry and sniffing technology. These flavor compounds increased from 3483.8 μg/kg (0 min) to 83,814.5 μg/kg (30 min). Nine odor-active compounds were selected based on odor activity value. Furthermore, 358 lipid molecules were identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, of which 139 were selected as lipid markers. Correlation analysis revealed significant correlations between the nine flavor markers and the levels of glycerophosphatides and glycerol lipids. Notably, 2-methylpropanal, 2-methylbutanal, and 2,5-dimethylpyrazine exhibited the same trends, consistent with precursors in the lipid degradation pathway. These results help elucidate the metabolic pathways involved in FSO flavor.

Keywords: Flaxseed oil; GC–MS-O; Key aroma; Lipidomics; Roasting process; UPLC-Q-TOF-MS.