Solubility of Fish Oil Components in Supercritical CO₂ and CO₂ + Ethanol Mixtures

Abstract

Solubility measurements for squalene, vitamin A palmitate, orange roughy oil, spiny dogfish liver oil, and commercial cod liver oil in supercritical carbon dioxide are reported over the temperature range 313−333 K and pressure range 200−300 bar. Solubility measurements are also reported for squalene, orange roughy oil, spiny dogfish liver oil, and cod liver oil in supercritical carbon dioxide + ethanol mixtures over the pressure range 200−300 bar at 333 K, and ethanol mass concentrations up to 12% by mass on a solute free basis. The use of ethanol as an entrainer substantially increased the solubility of all fish oil components. The increase in solubility, S, with ethanol concentration at fixed temperature and pressure was correlated by the empirical equation S = S 0 exp(kX), where S 0 is the solubility in pure CO2 at given temperature and pressure, k is a fitted constant, and X is the mass fraction of ethanol on a solute-free basis.

Production of omega-3 polyunsaturated fatty acid concentrates: A review

“…They observed that, at constant temperature, fish oil solubility increased significantly with pressure, whereas, at constant pressure, oil solubility decreased with temperature up to a pressure value from which oil solubility began to increase as temperature increased. This crossover behaviour has also been observed in other natural fish oils from sand eel (Borch-Jensen & Mollerup, 1997), orange roughy, spiny dogfish liver or cod liver (Catchpole, Grey, & Noermark, 1998). It is explained considering that, at constant pressure, a temperature increase has a double effect: the density of the solvent decreases, which would make solubility to decrease, and the vapour pressure of the solute increases, which would make the solubility to increase.…”

“…At low pressures the first effect predominates and at high pressures is the solute vapour pressure effect which becomes stronger (Brunner, 1994). It has been also observed that fish oil solubility increases by adding polar co-solvents such as ethanol (Catchpole et al, 1998).…”

Revision and summary of the group contribution equation of state parameter table: Application to edible oil constituents

“…Squalene equilibrium constant (k sq = weight fraction in vapor phase/weight fraction in liquid phase) in squalene + CO 2 binary mixtures. Comparison between experimental data [30,31] at (᭹) 313 K and ( ) 333 K and GC-EoS calculations using (· · ·) original parameters (Tables 1-3) and (-) parameters for high molecular weight compounds (Table 4). …”

Effects of polar cosolvents on cocoa butter extraction using supercritical carbon dioxide

“…Ethanol is commonly used as cosolvent or modifier for the extraction of natural products because the toxicity of ethanol to the human body is low (Catchpole, Grey, & Noermark, 1998;Temelli, 1992;Walsh, Greenfield, Ikonomou, & Donohue, 1989;Walsh & Ikonomou, 1987). Furthermore, it can be easily removed from the food matrix although there is a limited information regarding the effect of ethanol and other cosolvents on the SC-CO 2 extraction of cocoa butter.…”