Optimization of supercritical fluid extraction of linseed oil using RSM

Abstract

The objective of the present study was to develop a supercritical fluid extraction (SFE) method, suitable for extraction of total oil content from linseed, and to be used as a preparative technique for fatty acid determination. Optimum conditions (volume of added ethanol as a co-solvent, dynamic extraction time (DET), and pressure) were predicted in order to obtain the maximum yield of the extract. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used for modeling the process. Variable values ranged as follows: co-solvent 0-1 mL, DET 36-60 min, and pressure 45.57-62.05 MPa (6000-9000 psi). Effects of co-solvent volume and extraction pressure were well described by simplified polynomial equation (R 2 ¼ 0.85), since DET had no significant influence ( p>0.05) on the extract yield. The maximum yield of oil, calculated from experimental results, was obtained with 1 mL of co-solvent, and pressure of 62.05 MPa. Optimized conditions were used for extraction of oil from four samples of linseed, ground to pass through 1, 2, 3, and 4 mm-sieve, to determine adequate granulation for SFE. Finally, results for yield and fatty acid composition of the extract obtained using SFE were compared with the results of Soxhlet extraction.Practical applications: The obtained extracts can be used for fatty acid analysis, since they have not been damaged and their fatty acid compositions have not been degraded by reagents or aggressive extraction conditions. It is shown that the selection of appropriate milling equipment for grinding of samples is necessary to achieve adequate granulation and avoid fractionation of sample.

Supercritical fluid extraction of lipids from linseed with on-line evaporative light scattering detection

“…In this work we have compared our proposed SFE-ELSD method with the AOAC Method 945.16, a modification of the AOCS Method Ba 3-38, both based on Soxhlet extraction. On a more general note, this is the method that is usually seen as the reference method of choice in the literature when proposing new methods for total lipid determination, for example [8,[22][23]. The other suggested reference method is based on solvent extraction using a Butt-type apparatus, much like the Soxhlet apparatus.…”

“…Ivanov and Čolović [8] optimized the operating conditions for extraction of lipids from linseed using SFE. The conclusions were that a minor addition of ethanol mixed with the sample and the highest possible pressure of 62 MPa generated the highest recovery of lipids.…”

Stability of an extruded, linseed-based functional feed additive with the supplementation of vitamin E and carvacrol

“…A LECO TFE2000 fat analyzer (Michigan, USA) was used for SFE, using CO 2 with 99.995% purity. Extraction conditions were adjusted as explained in the paper by Ivanov et al (2012). FA methyl esters were prepared from the extracted lipids by transmethylation that uses 14% (w/w) boron trifluoride/methanol solution (Karlović and Andrić, 1996;Ivanov et al, 2012).…”

“…Extraction conditions were adjusted as explained in the paper by Ivanov et al (2012). FA methyl esters were prepared from the extracted lipids by transmethylation that uses 14% (w/w) boron trifluoride/methanol solution (Karlović and Andrić, 1996;Ivanov et al, 2012). The obtained samples were analysed by gas chromatography on an Agilent 7890A system (Agilent Technologies; Santa Clara, CA, USA) with a flame ionization detector (GC-FID), autoinjection module for liquid, equipped with fused silica capillary column (Supelco SP-2560 Capillary GC Column 100 m × 0.25 mm, d = 0.20 μm) (Supelco; Bellefonte, USA) and helium as a carrier gas (purity = 99.9997 vol %, flow rate = 1.5 ml · min -1 and pressure = 1.092 bar).…”

Recovery of oils from press cakes by CO2-based technology

“…For instance, on linseed, SFE optimization (Bozan and Temelli, 2002;Ivanov, 2012;Jiao, 2008;Özkal, 2009;Rombaut, 2013) showed that an increase of temperature and pressure increased the oil yield. Depending on extraction conditions, up to 82% of oil could be extracted with neat CO 2 .…”