Chemical composition and resistance to oxidation of high-oleic rapeseed oil pressed from microwave pre-treated intact and de-hulled seeds

The influence of a microwave (MV) pre-treatment (3, 6, 9 min, 800W) on the physicochemical properties of high-oleic rapeseed oil prepared from intact (HORO) and de-hulled seeds (DHORO) was investigated in this study. A control DHORO contained higher levels of total tocopherols and carotenoids, while higher concentrations of total phenolic compounds and chlorophylls were detected in the HORO. The MV pre-treatment caused a decrease in the unsaturated fatty acids content that was more evident for the DHOROs. The microwaving time significantly affected phytochemical contents and the color of both types of oils. A vast increase in canolol concentration was noticeable following 9 min of microwaving, which increased 506- and 155-fold in the HORO and DHORO, respectively. At the same time, the antioxidant capacity of oil produced from MV pre-treated seeds for 9 min was nearly 4 times higher than that of the control oil for both types of oils.