γ-Linolenic acid enrichment from Borago officinalis and Echium fastuosum seed oils and fatty acids by low temperature crystallization

Solvent winterization of seed oil and free fatty acids (FFAs) was employed to obtain γ-linolenic acid (GLA; 18:3ω6) concentrates from seed oils of two Boraginaceae species, Echium fastuosum and Borago officinalis. Different solutions of seed oils and FFAs from these two oils at 10%, 20% and 40% (w/w) were crystallized at 4°C, −24°C and −70°C, respectively, using hexane, acetone, diethyl ether, isobutanol and ethanol as solvents. Best results were obtained for B. officinalis FFAs in hexane, reaching a maximum GLA concentration of 58.8% in the liquid fraction (LF). In E. fastuosum, the highest GLA concentration (39.9%) was also achieved with FFAs in hexane.