OIL EXTRACTION FROM SEMI-DEFATTED PEQUI PULP RESIDUE USING NATURAL DEEP EUTECTIC SOLVENTS AS A SUSTAINABLE ALTERNATIVE

The Cerrado, a highly biodiverse biome in Brazil, faces increasing threats due to agricultural expansion, livestock farming and climate change. This biome is home to native species with high nutritional value, such as pequi (Caryocar brasiliense Camb), a Non-Timber Forest Product (NTFP) of economic importance. Pequi pulp has a high lipid content (up to 33 mg/100 g) and is traditionally extracted by cold pressing. The residue generated, a semi-defatted bagasse containing up to 40% lipids, offers potential for secondary extractions using solvents. This study aimed to evaluate the extraction of residual oil from semi-defatted bagasse from pequi pulp using ethanol associated with natural solvents - eutectic mixtures (NADES – Natural Deep Eutectic Solvents) and ionic liquids (IL) - as a sustainable alternative to traditional organic solvents. The bagasse was obtained via expeller extraction, dried for 19h at 40°C and homogenized, assisting in solute-solvent interaction. Extractions were performed in batches, using orbital shaking system at 60°C and 200 RPM, with solid solvent ratio of 1:4 (m/m) and time of 8 hours. Pure ethanol and its associations (20% by weight) with menthol, NADES (menthol:citric acid (1:1), menthol:acetic acid (1:1)) and IL (monoethanolamonium acetate) were evaluated. The extraction yield varied depending on the solvent: pure ethanol (56%), ethanol+menthol (84%), ethanol+menthol:citric acid (98%), ethanol+menthol:acetic acid (84%) and ethanol:IL (47%). The experimental results were compared with thermodynamic modeling, using COSMO-SAC model, where the lowest activity coefficient at infinite dilution did not correspond to the most efficient mixture. This discrepancy can be attributed to the complex interaction between the mixture components and the lipids in the solid matrix, which was not fully captured by thermodynamic modeling. It is concluded that eutectic mixtures have great potential in lipid extraction, offering a more efficient and environmentally friendly alternative to conventional solvents.