Extraction of pequi (Caryocar coriaceum) pulp oil using subcritical propane: Determination of process yield and fatty acid profile

Brazil is rich in oil plants that have natural antioxidants in their constitution, among which pequi (Caryocar coriaceum) stands out, a fruit represented by several species and the most common in the Northeastern Brazilian states such as Ceara and Pernambuco. This fruit has a lot of oil which can be used for nutritional and medicinal purposes. The aim of this research was to study the oil extraction process from pequi pulp, the quality of the extracts, kinetic modeling, and extraction with subcritical propane. Pequi fruits were extracted and their pulps were dried and ground. The oil extracted with subcritical propane was obtained at a pressure range of 5-15 MPa and temperatures of 303.15-333.15 K. The highest yield was 43.69% for the extraction condition of 15 MPa and 333.151 K. Ethanol and ethyl acetate were used in concentrations of 10-25% (volume) as solvent modifiers to obtain yields up to 44.99%. Soxhlet extractions were performed using ethanol and hexane as solvents and higher yield (52.78%) was obtained with the use of ethanol. The fatty acid analysis showed that different experimental conditions did not impact the fatty acid profile. The fatty acids found at greater proportion were palmitic acid (35.4%, in mass) and oleic acid (60.6%, in mass). The phenolic compound content was determined by the Folin-Ciocalteu method and showed no significant difference among the extraction methods used. Different mass transfer models (Crank, Sovova, and Martinez models) reported in the literature were used to model the extraction curves. The Sovova model had the best fit to the experimental data. (C) 2015 Elsevier B.V. All rights reserved.