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This study aimed to extract the oil from macauba pulp using a low-pressure solvent extraction, as well as characterisation of the extracts and defatted meal obtained using different solvents (n-hexane, ethyl acetate and isopropanol

In this study, the noncatalytic production of ethyl esters from used frying oil (UFO) in a continuous process was evaluated under supercritical conditions. Experiments were performed with the objective of evaluating the effect of the addition of water, a co-solvent (n-hexane), and ethyl esters to the reaction medium, applying different temperatures and keeping the oil:ethanol mass ratio (1:1), pressure (20 MPa), and residence time (40 min) fixed. The results demonstrated that the formation of fatty acid ethyl esters (FAEE) is favored at higher temperatures. The addition of 5 wt % water increased the yield, while no significant effect (p > 0.05) was noted with the addition of 10 wt % water. The addition of cosolvent and ethyl esters in the range investigated plays a vital role in maximizing the FAEE yields for most conditions studied. The presence of water and cosolvent reduced the degree of fatty acids decomposition, while the addition of ethyl esters increased this parameter. The effect of the residence time was investigated applying the best conditions observed and good reaction yields (>85 wt %) were achieved under different conditions.

The esterification of oleic acid in a continuous catalyst-free process using compressed ethanol was investigated in the present study. Experiments were performed in a tubular reactor and variables investigated were temperature, pressure, and oleic acid to ethanol molar ratio for different residence time. Results demonstrated that temperature, in the range of 473 K to 573 K, and pressure had a positive effect on fatty acid ethyl esters (FAEE) production. In the experimental range investigated, high conversions can be obtained at low ethanol concentrations in the reaction medium and it was observed that oleic acid to ethanol molar ratios greater than 1 : 6 show no significant increase in conversion. Nonnegligible reaction conversions (>90%) were achieved at 573 K, 20 MPa, oleic acid to ethanol molar ratio of 1 : 6, and 20 minutes of residence time.

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Macauba kernel oil (MKO) was extracted using supercritical CO 2 and compressed propane as the solvent. The influence of temperature (313-353 K for CO 2 and 303-333 K for propane) and pressure (18-22 MPa for CO 2 and 8-12 MPa for propane) on oil yield was investigated, and the results were compared with conventional extraction. A characterization of oil and defatted meal was performed. Temperature and pressure, in the evaluated range, influenced oil yield with the use of CO 2 . For propane, the oil yield was not influenced by the experimental conditions. In the evaluated experimental range, the use of propane and CO 2 provided 100 % and $93 % oil yield compared to conventional extraction, respectively. MKO showed a predominance of saturated fatty acids, among which lauric acid was the major constituent. CO 2 presented greater efficiency in the removal of phytosteroids and tocopherols from the macauba kernel, however, the oil extracted with propane presented longer oxidative stability. Defatted meals presented modified physico-chemical composition and potentiated technological characteristics due to oil removal. Solvent density; ÃÃ average value of three replicate runs AE standard deviation. Means followed by the same letters indicates no significant difference (p > 0.05).

The aim of this study was to investigate the extraction of oil from macauba pulp using ethanol and isopropanol as pressurized solvents. Experiments were carried out in a semi‐continuous extractor system at various temperatures (40, 60, and 80 °C) maintaining the pressure fixed at 10 000 kPa and the solvent flow at 3 mL/min and also using conventional extraction (in a Soxhlet). For both methods assessed, higher yields were obtained with the use of ethanol as the solvent. In the pressurized liquid extraction (PLE), an increase in temperature from 40 to 60 °C provided higher yields at 72 min of extraction, which was not influenced by the extraction carried out at 80 °C. This temperature effect was also observed in the extraction kinetics data. The maximum yields obtained by PLE were 44.78 % and 37.12 % with ethanol and isopropanol, respectively, which represents ∼77 % of the yield obtained by conventional extraction. Oleic and palmitic acids are the main fatty acids identified in macauba pulp oil, representing ∼88 % of the fatty acids composition, which was not influenced by the extraction method and solvent used. PLE with ethanol provides oils with higher levels of β‐carotene. The flavonoid content was higher with the use of isopropanol; however, it was not influenced by the method used.

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