Euphorbia lagascae seed oil obtained by pre-pressing and solvent extraction

This study evaluated the oil extraction from the Euphorbia lagascae seeds by pre-pressing followed by solvent extraction. The objective was to assess the effect of starting seed moisture content (MC) and heating temperature on oil extractability and quality of pressed and solvent-extracted oils. The expelling conditions evaluated seed moisture (5% and 10% MC) that were subjected to three temperature levels (ambient, 60 degrees C and 104 degrees C for 20 min) then screw-pressed. The press cakes were extracted with hexane using a Soxhlet extractor. Among the starting seed MC and heat treatment combinations evaluated, seeds with 5% MC and heated at 104 degrees C produced press cake with 16.4% oil content suitable for solvent extraction. Pre-pressing E. lagascae seeds without flaking adequately prepared the pressed cake for solvent extraction recovering 99.8% of the total oil. The combined press- and hexane-extracted oils had the lowest free fatty acid (FFA, 1.15%), diacylglycerides (DAG, 1.55%), and phospholipids (39 ppm P) contents. The vernolic acid content and the fatty acid composition of the extracted oils practically remained the same. Oil refining is necessary to reduce the FFA content and oil color to meet the specifications of the intended application.