Influence of seed roasting on the quality of glucosinolate content and flavor in virgin rapeseed oil

This study aimed to investigate the flavor variations, fatty acids (FA), and glucosinolates (GLSs) of virgin rapeseed oil (VRO) during roasting. VRO was evaluated and classified based on odor activity value and principal component analysis (PCA). Results showed that the total FA contents increased by 0.83%-1.56%, and the GLS contents decreased by 21.12%-29.85%. The total volatile compounds increased significantly during roasting, and their contents varied from 3.05 to 9.58 mg/kg to 301.21-831.15 mg/kg. The content of thiocyanate varied from 0.05 to 0.15 mg/kg to 6.52-26.87 mg/kg; the growth rate of aldehyde was greater than 64.05%; and the pyrazine content was 110 times higher than the initial content. The PCA results were also consistent with the results of sensory analysis in classification. The grass-like descriptor was mainly related to isothiocyanates, isoamyl cyanide, and dimethyl sulfide. The oxidized oil-like descriptor was mainly related to the FA content. The linolenic acid content increased by 5.58%-24.81%. The roasted and burnt descriptors were mainly related to 2,5-dimethyl-pyrazine, 3-ethyl-2,5-dimethyl-pyrazine, (E)-2-decenal, nonanal, and 2,3-butanedione. Rapeseed variety and roasting conditions influenced flavor formation and final flavor quality.