Correlating the solubility behavior of minor lipid components in supercritical carbon dioxide

Isolation of minor lipid components from complex lipid mixtures is receiving increased attention due to their biological activity and health benefits. Therefore. properties, health benefits and processing aspects of minor bioactive lipid components were reviewed. Literature solubility data of binary mixtures of minor lipid components (beta-carotene, alpha-tocopherol, stigmasterol and squalene) and supercritical carbon dioxide (SCCO2) were correlated using Chrastil's equation to determine the general trends of solubility behavior as affected by operating conditions and solute properties. Model parameters were estimated for the whole temperature range (a, b, k) and at each temperature (6, V). The slopes of solubility isotherms (k') were in the range of 4.9-10.6 for beta-carotene, 4.5-9.6 for alpha-tocopherol, 4.9-8.0 for stigmasterol and 7.3-7.6 for squalene. Estimated model parameters were used to compare solubility behavior of these solutes with components of olein glyceride series (oleic acid and triolein) as representatives of major lipid classes found in fats and oils. The findings provide the basis for the study of multicomponent lipid mixtures. Differences in the solubility behavior of components and the effect of operating conditions on solubility can be exploited for fractionation of these multicomponent mixtures to isolate the bioactive minor lipid components. (C) 2004 Elsevier B.V. All rights reserved.