Optimization of supercritical fluid extraction of linseed oil using RSM

Abstract

The objective of the present study was to develop a supercritical fluid extraction (SFE) method, suitable for extraction of total oil content from linseed, and to be used as a preparative technique for fatty acid determination. Optimum conditions (volume of added ethanol as a co-solvent, dynamic extraction time (DET), and pressure) were predicted in order to obtain the maximum yield of the extract. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used for modeling the process. Variable values ranged as follows: co-solvent 0-1mL, DET 36-60min, and pressure 45.57-62.05MPa (6000-9000psi). Effects of co-solvent volume and extraction pressure were well described by simplified polynomial equation (R2=0.85), since DET had no significant influence (p>0.05) on the extract yield. The maximum yield of oil, calculated from experimental results, was obtained with 1mL of co-solvent, and pressure of 62.05MPa. Optimized conditions were used for extraction of oil from four samples of linseed, ground to pass through 1, 2, 3, and 4mm-sieve, to determine adequate granulation for SFE. Finally, results for yield and fatty acid composition of the extract obtained using SFE were compared with the results of Soxhlet extraction. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.