Roasting treatments affect physicochemical, aroma and nutritional quality of strong fragrant rapeseed oil

Abstract

The strong fragrant rapeseed oil (SFRO) attracts the growing interest in China due to its fragrant flavor, attractive color, and physical and oxidative stability. It is usually produced with simple processes including rapeseed roasting, mechanical pressing, and degumming with hot water (80–90 °C). To produce SFROs with high quality and nutritional contents, the seed roasting parameters including temperature up to 220 °C and time ranging from 10 min to 30 min were investigated. Results showed that 20-min roasting at temperature 160 °C resulted in the highest oil extraction yield of 33.20% with the lowest water content of 0.121%. The produced SFRO had the roasted, nutty and soft tastes with the maximum overall score, the highest total tocopherol and sterol contents of 789.73 mg/kg and 4582.80 mg/kg, respectively, and high CoQ10 content of 65.57 mg/kg. Over-roasting at roasting temperature of over 180 °C and time of over 30 min led to the high Lovibond red readings, off-flavors, and increased concentrations of high saturated fatty acids and Benzo[a]pyrene (BaP). Our findings would provide a reference to produce SFROs with the highest extraction yield and nutrient contents, acceptable physicochemical properties, optimal profile of the fatty acids and the key aroma compounds, and relatively-low BaP concentration.