In search of sustainable alternatives for vegetable oils deacidification using oligomeric ionic liquid approach

Abstract

Crude vegetable oils contain free fatty acids (FFAs) that can compromise the sensorial quality and oxidation stability, and thus, need to be removed by deacidification processes. However, conventional physical and chemical processes are related to neutral oil and nutraceutical loss, need of catalysts, and high energy consumption. The liquid-liquid extraction of these bioproducts using sustainable solvents, such as ionic liquids (ILs), seems to be interesting alternative over processes using bioethanol and organic solvents. In this work, the use of protic FA-based IL, such as diethanolammonium caprate ([H2EA][C10OO]) as solvent for deacidification of vegetable oils through the oligomeric IL approach was investigated. The liquid-liquid equilibria (LLE) data of systems containing [H2EA][C10OO], FA (palmitic, oleic and linoleic acids) and vegetable oil (palm olein, canola or soybean oils) were determined and modelled using NRTL model. IL presented good extraction efficiency of FFAs, presenting high distribution coefficient. Also, the NRTL model well described the LLE of such kind of systems. Moreover, solute-solvent affinity was evaluated by predictive COSMO model for a better comprehension of the results. Therefore, the results might indicate that protic FA-based ILs might have potential applicability as alternative solvents for deacidification of crude vegetable oils.