Effects of Rapeseed Varieties on the Flavor and Comprehensive Quality of Fragrant Rapeseed Oil

The volatile components of the seed oils from canola (Brassica napus) and Indian mustard (Brassica juncea) extracted under the same conditions were determined by solvent-assisted flavor evaporation (SAFE) combined with gas chromatography-mass spectrometry (GC-MS). Based on odor activity value (OAV), partial least squares discriminant analysis (PLS-DA) was used to identify the key volatile flavor components to discriminate the two oils according to their sensory flavor. The results showed that 82 volatile components of 12 kinds and 90 volatile components of 11 kinds were detected in canola and rapeseed oil in a total quantity of 22377.88 and 157512.98 μg/kg, respectively. Meanwhile, the total amounts of thioside degradation products were 3311.07 and 146492.82 μg/kg, and the total amounts of phenolic substances were 12125.47 and 4613.03 μg/kg, respectively. The 13 most important characteristic flavor substances were identified using PLS-DA in combination with OAV, namely 6-methylthiohexanenitrile, 5-(methylthio)-valeronitrile, benzenepropionitrile, 3-butenyl isothiocyanate, benzeneacetonitrile, trans-2-decenal, n-hexanol, linalool, ethylbenzene, phenylethanol, gamma-nonanolactone, 4-vinyl-2,6-dimethoxy-phenol, and 3-methylcrotononitrile. 6-Methylthiohexanenitrile, phenylacetonitrile, linalool, 5-(methylthio)-valeronitrile, benzyl propionitrile, and 3-butenyl isothiocyanate all contributed to the unique pungent flavor of rapeseed oil, and phenyl acetonitrile and linalool were detected only in traditional rapeseed oil; n-hexanol, phenylethanol, and gamma-nonanolactone were more abundant in canola oil and had an important effect on the sweetness ofrapeseed oil. The results of sensory evaluation showed that the sweetness of canola oil was better than traditional rapeseed oil, while the pungency of traditional rapeseed oil was stronger. Erucic acid was not detected in canola oil, while the content of erucic acid in traditional rapeseed oil was 30.25%. The total content of vitamin E and sterols in canola oil was higher than that in traditional rapeseed oil. The results of this study offer support for the selection of raw materials and odor markers for the production of different aroma types of rapeseed oil.