Selectivity of Supercritical CO₂ in the Fractionation of Hake Liver Oil Ethyl Esters

Abstract

The solubility of different ethyl esters derivatized from hake liver oil in supercritical carbon dioxide was studied. A selectivity factor was used to determine optimal conditions to fractionate the ethyl ester mixture. A strong influence of solvent pressure and temperature was observed within8.63-18.04 MPa and 40-70°C. The lowest total solubility of the ethyl ester mixture was obtained when using supercritical carbon dioxide at the lowest density (the lowest pressure and the highest temperatures value tested). The highest discrimination against long-chain polyunsaturated fatty acids (e.g. EPA and DHA) was also obtained at these above conditions. Conversely, higher solubility and lower selectivity were obtained when solvent density increased. Considering this inverse correlation between selectivity and solubility, a single-step batch-fractionation process was designed to increase the 22:6 ethyl ester content from an initial value of 17.5% in the starting material to 55% in the final extract.

Combination of Urea Complexation and Molecular Distillation to Purify DHA and EPA from Sardine Oil Ethyl Esters

“…EPA and DHA are principally obtained from fish oil and methods to enrich EPA and DHA from this source have attracted great attention. There are reports of a variety of methods to purify EPA and DHA from fish oil, including the use of low-temperature crystallization [6], metal ion complexation extraction [7], supercritical fluid extraction [8,9], urea complexation (UC) [10], lipase-catalyzed hydrolysis [11] and molecular distillation (MD) [12]. Each method has advantages, but also presents some problems to restrict their applications because the solvents they use are flammable or toxic, the production cost is high, and/or the yield is low.…”

Storage stability and quality of polyunsaturated fatty acid rich oil fraction from Longtail tuna (Thunnus tonggol) head using supercritical extraction

“…A SC-CO 2 fractionation process offers the advantages of high purity, selective fractionation, single step processing, and environmental friendly. In addition, it can be efficiently managed at mild operating temperatures without exposing the extract to oxygen, thereby preserving the integrity of the PUFA of interest and avoiding solvent residues in the final product (Jachmanián, Margenat, Torres, & Grompone, 2007;Staby & Mollerup, 1993). Fractionation and purification of fish oil omega-3 PUFA have been studied by many researchers during the past 10 years (Catchpole, Grey, & Noermark, 2000;Corrêa et al, 2008;Jachmanián et al, 2007;Létisse & Comeau, 2008;Perretti et al, 2007).…”

Fractionation of fish oil with supercritical carbon dioxide

“…A supercritical fluid separation process using carbon dioxide as the solvent offers potential advantages because it is non-flammable, non-toxic and inexpensive, and can be used under mild operational conditions. Some researches on the supercritical extraction of fish oil and mainly of fractionation of EPA and DHA as fatty acid ethyl esters from fish oils are shown in Table 1, such as the SC-CO 2 extraction of oil from sardine (Létisse et al, 2006); the influence of moisture from the matrix (Atlantic Mackerel) on the oil yield and on the changes in sarcoplasmatic proteins of matrix after SC-CO 2 extraction (Dunford et al, 1997); the SC-CO 2 fractionation of EPA and DHA as fatty acid ethyl esters (Perretti et al, 2007;Jachmanián et al, 2007;Gironi and Maschietti, 2006;Jaubert et al, 2001;Riha and Brunner, 1999;Espinosa et al, 2002;Alkio et al, 2000) and the phase equilibrium for SC-CO 2 and fish oil, including free fatty acids, cholesterol, wax esters, di-and triacylglycerols were carried out (Borch-Jensen and Mollerup, 1997) in order to supply information on the deodorization of fish oil by stripping. The measurement show that fish oil may be deodorized to remove the free fatty acids, cholesterol and most of the wax esters at temperatures above 353 K and pressures at 350-500 bar.…”

“…Létisse et al, 2006; Dunford et al, 1997; Perretti et al, 2007; (d) Jachmanián et al, 2007; Gironi and Maschietti, 2006; Jaubert et al, 2001; Riha and Brunner, 1999; (h) Espinosa et al, 2002;(i) Alkio et al, 2000 (j) Borch-Jensen and Mollerup, 1997. Experimental system: CO 2 cylinder (i), refrigeration bath (ii), high pressure pump (iii), CO 2 tank (iv), manometers (v,vi), equilibrium cell (vii), Erlenmeyer flask (viii), peristaltic pump to clean the system (ix).…”