Comparison of volatile compounds of hot‐pressed, cold‐pressed and solvent‐extracted flaxseed oils analyzed by SPME‐GC/MS combined with electronic nose: Major volatiles can be used as markers to distinguish differently processed oils

Abstract

Abstract Analysis of volatile profiles from differently processed flaxseed oils (FSO) was performed by SPME‐GC‐MS, electronic nose (E‐nose) and descriptive sensory analysis. A total of 61 volatiles were tentatively identified and then quantified. Among these components, 51 volatiles were obtained from the hot‐pressed FSO, 47 from cold‐pressed FSO, and 40 by solvent extraction. Principal component analysis (PCA) demonstrated that three FSO samples tested resulted in significant differences of three treatments ( p <0.05) and the marker compounds that contributed to discrimination of different processed FSO were hexanal, (E, E)‐2, 4‐pentadienal, (E, E)‐2, 4‐heptadienal, 6‐hydroxy‐2‐hexanone, 1‐hexanol, methyl‐pyrazine, nonanal, 2,3‐pentanedione, 1‐butanol, acetic acid, hexanoic acid, and ethyl acetate. In addition, there was good consistency among GS‐MS, sensory evaluation and E‐nose analysis results. These results indicated that the process method has a significant effect on the aroma quality of FSO and may be helpful in evaluating aroma quality and the detection of frauds. Practical applications: The results showed that the major volatile components could be used as chemical markers to distinguish differently processed FSOs by the chemometric method. There was good consistency among GS‐MS, sensory evaluation and E‐nose analysis results, suggesting that E‐nose technique combined with a PCA of the data provided by the sensor arrays has the good potential to evaluate FSO quality and the detection of frauds. Sixty‐one volatiles were identified and significant differences were found in different processed flaxseed oils. Twelve major volatile compounds contributed to discrimination of different processed flaxseed oils. Flaxseed oil samples were distinguished from each other through PCA of E‐nose data, suggesting that the E‐nose can successfully discriminate different processed flaxseed oils.