Abstract
The effect of roasting time on the contents of bioactive compounds (tocopherols, phytosterols, phenolic compounds), antioxidant capacity and physicochemical properties of rapeseed oil pressed from de-hulled seeds was investigated. The de-hulled seeds were roasted at a temperature of 165 °C for 20, 40, 60, 80, and 100 min. The results of this study show that a roasting pre-treatment led to a gradual increase in canolol content (from 1.34 to 117.33 mg/100 g), total phytosterols (from 573.51 to 609.86 mg/100 g) and total carotenoids (0.82 to 2.41 mg/100 g), while only slight changes in the contents of tocopherols were noted. With the increase in roasting time a gradual increase in oxidative stability (from 4.27 to 6.85 h), and antioxidant capacity, seen mainly in the hydrophilic fraction of oil (from 0.32 to 2.30 mmol TEAC/l) was found. Although roasting resulted in the formation of primary and secondary oxidation products, the quality parameters of oils were within Codex Alimentarius limits.
Highlights
The EU is the world’s largest producer of rapeseed and its products
The seed roasting for 100 min resulted in an increase of the PC-8 content of 73.6%, compared to the control oil sample
Following 100 min of seed roasting the concentration of chlorophylls in the oil increased to 0.70 mg/kg, which is consistent with the results presented by Prior et al (1991), who reported that heating rapeseeds at 80–100 °C for 30 min significantly affected chlorophyll content (6.5 mg/kg for cold-pressed oil, up to 47.3 and 67.8 mg/kg for roasting at 80 and 100 °C, respectively)
Summary
The EU is the world’s largest producer of rapeseed and its products. The leading countries in rapeseed production in the EU are Germany and France, followed by the U.K., Poland, and the Czech Republic (FAOSTAT, 2015). Besides the food use of rapeseed, its meal is used in the livestock sector as the EU is a leading producer and exporter of meat and dairy products. The embryo contains two pieces of cotyledons (which serve as food reserve structures), radicle and hypocotyl (Hu et al, 2013). The oil in this oilseed is distributed in spherosomes throughout the germ cell. Rapeseeds are composed of 38–50% lipid, 20–32% protein, and 10–15% crude fiber. The respective oil contents for hulls and kernels range from 10.6 to16.4% (dry basis) and from 47.1 to 59.6%. Crude fiber contents range from 27.0 to 44.1% (dry basis) in de-fatted hulls and 3.0% to 12% in de-oiled kernels (Carré et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
