Extraction of sunflower oil using ethanol as solvent

Abstract

The ethanolic extraction of oil from sunflower collets was studied and compared with previous data where hexane was used as extraction solvent. First, the extractive power of ethanol was determined by Soxhlet. It gave a higher yield of extracted material, whose content of soluble hexane components (oil phase) was similar to that obtained with n-hexane. When ethanol was used as solvent, 70% less crystallizable waxes and at least 38% more tocopherols and phospholipids were extracted. In addition, ethanol showed great ability to extract sugar, mainly raffinose and sucrose, extracting over 75% of the initial sugar content. Then, the kinetics of ethanolic extraction was studied at 50 and 60 C in a batch reactor. At equilibrium conditions, it was observed that extraction could be limited by the solubility of the extractable material. Oil effective diffusivities were 9.94 10-10 at 50 C and 3.11 10-9 m2 /s at 60 C. From the point of view of the quality of the obtained products, this work demonstrated the feasibility of using ethanol as an alternative solvent to hexane in the oil extraction from sunflower collets.