Changes in the Content of Phenolic Compounds in Flaxseed Oil During Development

The phenolic fraction of flaxseed oil was quantified during the development of three varieties (H52, O116 and P129). Seed samples were collected at regular intervals from 7 to 56 days after flowering (DAF). During oilseed processing, less polar compounds are co-extracted with oil. The methanolic extracts were obtained by solid phase extraction. Separation of phenolic compounds was conducted by high-performance liquid chromatography-mass spectrometry. The main phenolic compounds detected during maturation were: diphyllin, pinoresinol, matairesinol, secoisolariciresinol, vanillic acid, ferulic acid and vanillin. The highest amount of lignans (6.74 mg of analyte/kg of flaxseed oil) was detected at 7 DAF in P129 variety. The maximum level of phenolic acids (2.57 mg of analyte/kg of flaxseed oil) was reached at 7 DAF in P129 which had also the highest content of simple phenols (1.37 mg of analyte/kg of flaxseed oil) at the same date after flowering. At full maturity, the content of phenolic compounds in three varieties ranged from 0.26 to 0.36 mg of analyte/kg of flaxseed oil. The highest content of total phenolic compounds using the Folin–Ciocalteu method was detected in P129 variety (196.42 mg CAEs/kg of flaxseed oil) at 7 DAF. Results of this study indicate that flaxseed oils contain different amounts of phenolic compounds using different methods.