Pressurized liquid extraction of soybean oil using intermittent process with ethanol and hexane as solvent: Extraction yield and physicochemical parameters comparison

Abstract

AbstractThis research demonstrates pressurized liquid extraction (PLE) in an intermittent process in obtaining soybean oil using less solvent than conventional extraction. Temperature (T), solvent rinse volume (VS), contact time between the solvent and the matrix (St) in each cycle and number of cycles (C) were screened. Yield, fatty acids profile (FAs), and triacylglycerols were evaluated. After preliminary testing, T and St were tested for yield while VS, C, and P were fixed at 60% of total volume of the fixed bed extractor, 3 cycles, and 10.34 MPa respectively. The highest oil recoveries were 94.40% (85°C, 13 min, with hexane) and 86.16% (80°C, 12 min, with ethanol). The mass ratio of solvent/feeds resulted in a yield increase of 1.47% (hexane) and 3.99% (ethanol). The concentration of β‐sitosterol (≤182.78 mg/100 g of oil, hexane; ≤71.64 mg/100 g of oil, ethanol) and the fatty acid profile were not affected by the different solvents or process. The main fatty acids were linoleic (≤51.12%, ethanol; ≤40.31%, hexane) and oleic (≤24.98%, ethanol; ≤26.62%, hexane). The main triacylglycerols identified were LLO, LLL, and OOL. The results indicate that soybean oil can be obtained by a new process that uses a safe and renewable solvent, indicating that PLE in an intermittent process can replace conventional extraction without changing the main characteristics of the oil, with good yield using less solvent.Practical applicationsThe practical application of this research is related to the possibility of demonstrating the feasibility of PLE in obtaining soybean oil using pressurized ethanol. The solvent used in most oilseed extraction plants is commercial hexane, a toxic and non‐renewable solvent. The experiments were carried out with pressurized hexane to demonstrate the economy of solvents and compare with the results obtained when pressurized ethanol was used as a solvent. The ethanol study aimed to show high extraction yields, even using a polar solvent in soybean oil extraction. High yields and oil characterization showed that it is possible to use a green and clean technology to obtain vegetable oils.