Changes in the physicochemical characteristics and lipid concomitant of rapeseed oil during germination

Summary This study aimed at determining the changes in physicochemical characteristics and lipid concomitant of rapeseed oil during germination. Rapeseeds of two varieties, namely Shanyou 28 (Sy 28) and Qinyou 10 (Qy 10), were germinated. Oil was obtained by roasting, pressing and moderate refinement. The germination of 12–48 h led to a reduction in acid value, and 24–72 h led to a decrease in peroxide value. α‐Tocopherol content increased consistently throughout the entire period, increasing to 2.96‐ and 2.50‐fold at the end of germination. In the germination process of 36–72 h, β‐sitosterol, campesterol and brassicasterol content increased gradually. At 72 h, the total phytosterol content rose modestly (1884.02–2071.55 and 1743.96–2691.72 mg kg −1 ). Carotenoid content increased dramatically (5.81–12.68 and 2.54–12.35 mg kg −1 ). An increase occurred in unsaturated fatty acids from 24 to 72 h, whereas saturated fatty acids decreased. These findings indicated that germination enhanced α‐tocopherol, phytosterol and carotenoid, as well as the fatty acid composition, thereby improving the nutritional value and edible quality of oil. Among various constituents, α‐tocopherol in oil could be considered as a reference marker to distinguish the germination stage and estimate the nutritional value of rapeseed oil.