Effect of refining and pressing temperature on chemical attributes of canola oil produced in Chile

Abstract The consumption of vegetable oils is common in our daily diet. Rapeseed oil (canola oil) is the third most consumed edible oil in the world, followed by palm and soybean oils in terms of production. Rapeseed oil has a low proportion of saturated fatty acids, while it is rich in unsaturated fatty acids, as well as in healthy compounds such as phenols, tocopherols, phytosterols, carotenoids, and fat-soluble vitamins. However, processing technologies affect the content and functional activities of bioactive compounds in the oil. Aim: To assess any potential effect of hot or cold pressing and a refining process on the nutritional value and the profile of several bioactive compounds in canola oils produced in Chile. Methods: Canola oils were characterized regarding their fatty acid profile, phytosterol and tocopherol composition, total phenol content, and antioxidant activity, according to the mode of extraction (cold or hot pressed) and before and after bWeing subjected to a refining process. Results: Fatty acid profiles were not significantly different in any of the analyzed canola oils. Refining but not temperature extraction led to a sharp decrease of phytosterols and tocopherols. Hot pressing significantly increased the amount of total phenols (3.1 times) and the antioxidant activity measured by ORAC (3.1 times) and DPPH (8.3 times) compared to the cold extraction. However, phenolic concentration and antioxidant capacity decreased after refining. Conclusions: Refining processes should be adjusted to reduce the loss of bioactive compounds in the oil.