Cintia B. Gonçalves

Deacidification of Vegetable Oils by Solvent Extraction

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.

Extração de oleuropeína a partir de folhas de oliveira utilizando solvente hidroalcoólico

Olive leaves contain oleuropein, a substance known for its antioxidant, antimicrobial and antiinflammatory potentials, amongst others. The objective of this work was to study the extraction of oleuropein using a hydroalcoholic solvent. Olive leaves (OL) were macerated at 25 °C with a solvent (S) consisting of a mixture of ethanol and water (70:30 v/v), with OL:S mass ratios equal to 1:8, 1:6 and 1:3, with or without the presence of acetic acid. The highest oleuropein content found in the freeze dried extract (approximately 18 g/100 g) was obtained from the procedure using an OL:S ratio = 1: 3, in the presence of acetic acid. Finally, a test was carried out to verify the effect of the freeze dried extract on the induction time in samples of extra-virgin and refined olive oil, and increases of 3 and 2 hours, respectively, were observed. It was concluded that it is possible to obtain olive leaf extracts using renewable solvents, and that oleuropein can act as a natural antioxidant in olive oil, improving its oxidative stability.