Supercritical carbon dioxide extraction of rubber seed oil rich in alpha-linolenic acid
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Date
2015
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Publisher
Universiti Teknologi Malaysia
Abstract
The demand for omega-3 fatty acids is increasing dramatically; the use of conventional solvent extraction technique has risen up safety and hygiene issues. Therefore, supercritical carbon dioxide (SC-CO2) extraction as a non-toxic and green method was performed to extract rubber seed oil rich in alpha-linolenic acid. The effect of pressure, temperature and flow rate on the overall oil yield and alphalinolenic acid (ALA) concentration and oil solubility were investigated. The experimental oil solubility was also correlated with the solvent density based models at different flow rates and optimization of extraction conditions was carried out using response surface methodology (RSM). Rubber seed with low moisture content was used to prevent the moisture from acting as mass transfer barrier. Larger particle size of 500 µm was chosen for extraction due to the oily physical property of rubber seeds and the SC-CO2 extraction was performed at 180 minutes constantly throughout this study. The results revealed that the extraction process was dependent on flow rate. In addition, the cross over pressure phenomena between 22-23 MPa was observed at 4 mL/min of flow rate. Extraction performed at 4 mL/min of flow rate showed that the overall oil yield increased with the increase of pressure while the overall oil yield reached the optimum value at a pressure of 25 MPa with a flow rate of 2 and 3 mL/min. The overall oil yield increased with increasing temperature at 4 mL/min of flow rate while a reverse effect was observed at lower flow rate. The experimental solubility data best fitted the del Valle-Aguilera model. Furthermore, SC-CO2 extraction gave higher ALA concentration as compared to conventional solvent extraction. Hence, in this research, SC-CO2 extraction is the best technique to extract high quality and purity rubber seed oil rich in ALA
Description
Thesis (PhD. (Chemical Engineering))
Keywords
Hevea seed oil, Extraction (Chemistry), Linolenic acids