Flavor Quality Characterization of Rapeseed Oil During Storage by Physicochemical Analysis, Sensory Evaluation, Electronic Nose, and GC–O

Abstract

Background: Rapeseed oil is the most widely consumed vegetable oil globally. However, the key aroma-active compounds of rapeseed oil and their changes during storage are unclear. In this study, the flavor of rapeseed oil during storage was characterized by physicochemical analysis, sensory evaluation, electronic nose (E-nose), and gas chromatography–olfactometry (GC–O).

Results: Peroxide value, acid value, and anisidine value gradually increased, while polyphenol content, tocopherol content, and sterol content showed a downward trend during storage. The E-nose combined with the linear discriminate analysis (LDA) method could discriminate rapeseed oil with different storage times. The sensory attributes changed significantly from distinctive pickled aroma to rancid, green, and fried aromas during storage. This work provides the aroma-active markers based on GC–O–MS for the quality evaluation of rapeseed oil during storage. A total of 136 volatile compounds were detected by GC–MS, and 16 odorants were identified by GC–O combined with aroma extract dilution analysis (AEDA). Finally, seven aroma-active volatile compounds (3-butenyl isothiocyanate, 2(5H)-furanone, 2-methoxy-4-vinylphenol, (E)-2-octenal, (E,E)-2,4-heptadienal, (E,E)-2,4-decadienal, and 3-methyl-pentanoic acid) with the odor activity values (OAVs) greater than 1 were identified as potential key aroma volatiles that contributed significantly to the overall aroma of rapeseed oil.

Conclusion: This study provided a comprehensive method to monitor the flavor quality change of rapeseed oil during storage. The identified volatile compounds could be the markers to characterize the quality changes of rapeseed oil during storage.