The refining of edible oils requires a series of purification steps, with the most important being the decrease of the free fatty acid level of the crude oil. This step is very important for the quality of the final product and has a major impact on the economic feasibility of the whole process. Several techniques, alternative to the conventional caustic or steam distillation methods, are suggested in the literature, such as supercritical extraction, membrane technology and solvent extraction. In the present paper we discuss the main aspects related to the solvent extraction technique, coupled or not with the conventional methods. The reviewed patents indicate various advantages of a purification process based on the selective extraction of free fatty acids using short chain alcohols. Its technical feasibility is due to the differences in solubility of free fatty acids and neutral oil in the proposed solvents. This alternative technique does not generate waste products and can preserve nutraceutical compounds in the refined oil.
Keywords: Oil deacidification, free fatty acid extraction, ethanol, oil refining, vegetable oil or edible oil, oil extraction, short chain alcohols, isopropanol or n-propanol
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