Optimization of the Supercritical CO2 Extraction of Oil from Rapeseed Using Response Surface Methodology

Optimization of the Supercritical CO₂ Extraction of Oil from Rapeseed Using Response Surface Methodology

Marina Cvjetko¹, Stela Jokić²*, Žika Lepojević³, Senka Vidović³, Branimir Marić⁴ and Ivana Radojčić Redovniković¹¹Faculty of Food Technology and Biotechnology, Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
²Faculty of Food Technology, Osijek, F. Kuhača 20, HR-31000 Osijek, Croatia
³Faculty of Technology, Novi Sad, Bulevar Cara Lazara 1, RS-21000 Novi Sad, Serbia
⁴SGS Beograd Ltd, SGS Serbia Multilab, Danila Kiša 20, RS-21000 Novi Sad, Serbia

Article history:
Received June 28, 2011
Accepted March 20, 2012

Key words:
fatty acids, kinetics, rapeseed oil, response surface methodology, supercritical CO₂ extraction

Summary:
Three operating parameters (pressure, temperature and extraction time) of the supercritical CO₂ extraction of oil from rapeseed have been optimised by response surface methodology to obtain high yield of oil. Results showed that data were adequately fitted into the second-order polynomial model. The linear and quadratic terms of independent variables of temperature, pressure and extraction time had a significant effect on the oil yield. Optimal conditions for oil yield within the experimental range of the studied variables were 29.7 MPa, 52.14 °C and 3.36 h, and oil yield was predicted to be 28.27 %. In addition, the mass transfer model was used to describe the extraction kinetic curves of rapeseed oil and very good agreement was found between the observed and predicted values. The fatty acid composition of rapeseed oil extracted by supercritical CO₂ at optimal operating parameters and that by n-hexane were analysed by gas chromatography. The obtained oil showed similar fatty acid composition with an unsaturated fatty acid content up to 92.9 %.

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