Determining the significant factors affecting solvent oil extraction from wild safflower seeds using fractional factorial design

Wild safflower is a plant resistant to dry climate and the seeds are used for producing edible or industrial oils. The objective of this research was to investigate the factors affecting solvent oil extraction from wild safflower seeds. The effect of 5 factors including solvent temperature (50 and 70°C), time of extraction (4 and 6 h), volume of solvent (200 and 300 ml), mass of the seeds (20 and 30 g) and size of the ground seeds (1.0 and 1.5 mm) on extracting oil by Soxhlet extractor was investigated using fractional factorial experiments based on completely randomized design (α=0.01 and α=0.05). After determining the significant factors, the value of the factors were optimized using response surface methodology based on the central composite design method. The experiments performed by fractional factorial experiments showed that extraction time (α=0.01), size of seed particles (α=0.01) and solvent volume (α=0.05) had meaningful effects on the oil extraction yield. The experiment performed based on central composite design indicated that particle size (α=0.01), extraction time (α=0.01), volume of solvent (α=0.05), and the interaction of time and solvent volume (α=0.01) had significant impact on the oil extraction yield. From the 5 investigated factors, time of extraction and the size of ground seeds (α=0.01) and the volume of solvent (α=0.05) had significant effects on the oil extraction yield. The optimized values for extraction time, volume of solvent and the size of the ground seeds were 6:40 h, 335 ml and 1.1 mm, respectively. The maximum oil extraction yield at the optimum conditions was 36.6%.