Recovery of oils from press cakes by CO2-based technology

Abstract

In a context of a strong demand for vegetable oils, the development of new “green” processes is essential to provide methods that avoid the use of organic solvents, work at relatively low temperatures and preserve the quality of the final products. The supercritical fluid extraction (SFE) process meets these objectives. In this study, five meals (hemp, flax, sesame, poppy and walnut) were subjected to SFE at 45 °C and 250 bar in the presence of ethanol as co-solvent. Using this method, between 77 and 98% of the lipids present in the meal could be extracted. Except for poppy, 50% of the lipids present in the cake were recovered as a separate oily liquid phase. SFE was not selective toward certain types of triglycerides: the oils obtained exhibited the same fatty acid profile than the total lipid extracts from the cakes. In contrast, the composition in minor lipid components was dependent on the type of meal investigated. For example, hemp lipid extract was particularly rich in chlorophyll.

Keywords

• Supercritical fluid extraction
• press cake
• oil recovery
• oil quality