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Experiments to determine the number of transfer units (NTU) and height of a transfer unit (HTU) of different random packings such as Raschig rings, Dixon rings, Fenske rings and glass beads in a countercurrent (CC) supercritical fluid extraction (SFE) column of 17.6 mm I.D. and 1.8-m length at 20 MPa and 313 K, with olive oil and CO2, were performed. The extracts were collected by means of two separators, the first one operated at 10 MPa and 313 K and the second at 3 MPa and 273 K. The performance of SFE was studied by analyzing the content of vitamin E and sterols in the raffinate and in the collected extracts by HPLC equipped with a photodiode array detector. The value of HTU and the NTU were evaluated for each random packing at solvent to feed ratios from 23.14 to 41.65 kg CO2/kg oil. Fenske rings showed the best results in terms of efficiency and performance of the CC system for the SFE of olive oil. [Copyright &y& Elsevier]

Optimization of the countercurrent supercritical fluid extraction (CC-SFE) conditions to obtain high quality brandy aroma extracts is presented. The main variables that influence CC extraction selectivity and efficiency have been studied, such as extraction pressure and temperature and sample flow rate (related to the solvent-to-feed ratio). A rotatable central composite experimental design is used to optimize the combination of these experimental. Experiments have been performed with brandy using a CC-SFE system at pilot plant scale. The beverage is put directly in contact with the carbon dioxide in a packed column and the extracts are recovered in two different fractionation cells, where depressurization occurs. For each experiment, two extracted fractions and a raffinate are obtained and its aroma characterized by gas chromatography. A statistical study of the data obtained is performed including analysis of variance (ANOVA), fitting of a regression model and response surface study. The obtained results allow to know the variables that clearly influence the process and also show the interest of CC-SFE as an useful technique to obtain high-value concentrated brandy aroma extracts. [Copyright &y& Elsevier]

The edible oil processing industry involves large losses of organic solvent into the atmosphere and long extraction times. In this work, fast and environmentally friendly alternatives for the production of echium oil using green solvents are proposed. Advanced extraction techniques such as Pressurized Liquid Extraction (PLE), Microwave Assisted Extraction (MAE) and Ultrasound Assisted Extraction (UAE) were evaluated to efficiently extract omega-3 rich oil from Echium plantagineum seeds. Extractions were performed with ethyl acetate, ethanol, water and ethanol:water to develop a hexane-free processing method. Optimal PLE conditions with ethanol at 150 °C during 10 min produced a very similar oil yield (31.2%) to Soxhlet using hexane for 8 h (31.3%). UAE optimized method with ethanol at mild conditions (55 °C) produced a high oil yield (29.1%). Consequently, advanced extraction techniques showed good lipid yields and furthermore, the produced echium oil had the same omega-3 fatty acid composition than traditionally extracted oil. [ABSTRACT FROM AUTHOR]

Abstract: Lipase-catalyzed transesterification of 1-O-octadecyl glycerol (batyl alcohol) with ethyl butyrate has been studied. The effect of vacuum on the rate of both transesterification and distillation of ethyl butyrate has also been investigated and at different reaction conditions, more than 85% of 1-O-octadecyl glycerol was consumed in only 5min giving rise to the monoester. Then the monoester is again acylated to produce the diesterified product. In addition, the transesterification reactions were effected in solvent free reaction medium and it has been scaled-up to produce up to ca. 500g of 2,3-dibutyroil-1-O-alkylglycerols in three consecutive cycles reutilizing the same batch of lipase. An efficient evaporation of ethanol was necessary to significantly reduce the reaction times of the transesterification reaction. Finally, a kinetics model describing both the rate of transesterification and the rate of inactivation of the immobilized lipase has been developed. The results indicate that the operational stability of the immobilized lipase confined into the mesh baskets (according to the value of k d attained), was very high and that provides a half-life of the lipase higher than 1500h. The present procedure is intended to be used for the synthesis of homogeneous alkylglycerols with biological activities and/or precursors of structured alkylglycerols. [Copyright &y& Elsevier]

Highlights • Enzymatic synthesis of omega-3 FAEE from chia oil has been achieved. • Lipase from Thermomyces lanuginosus (TLL) was immobilized and coated by a layer of PEG. • Commercial lipases were compared in the transesterification of seed oil. • Lipase comparison for FAEE production showed higher stability for modified lipases. • Highly concentrated α-linolenic esters were produced under mild conditions. Abstract Enzymatic synthesis of fatty acid ethyl esters (FAEE) from chia (Salvia hispanica L.) oil has been performed with different modified derivatives and compared with commercial immobilized lipases to produce omega-3 rich FAEE. Therefore, the main objective was to synthesize omega-3 esters from chia oil catalysed by polyethylene glycol-modified lipases using a biocatalyst with higher stability than commercial derivatives. Lipase from Thermomyces lanuginosus (TLL) was immobilized by hydrophobic adsorption on Sepabeads C-18 followed by a physicochemical coating of lipase surface with a dense layer of PEG. Ethanolysis reactions were carried out using pressurized liquid extracted chia seed oil and with different lipase derivatives to compare the omega-3 FAEE yield and ratio of reaction products, which were analysed by HPLC-ELSD. Furthermore, reutilization of lipase derivatives was studied to evaluate the stability after several reaction cycles to minimize decreasing of catalytic activity and develop a feasible enzymatic process for food industrial applications. [ABSTRACT FROM AUTHOR]

Abstract: Rosmarinus officinalis (rosemary) extracts were obtained in a supercritical pilot-scale plant. Based on experimental information available in the literature for analytical or low-scale processes, extraction temperature and pressure were selected to be 313K and 30MPa. At these extraction conditions, the kinetic behavior of the pilot-scale overall extraction curve were determined with respect to yield, antioxidant activity and carnosic acid content. The overall extraction curve was represented using Sovova''s model; the average deviation between measured and calculated yields was lower than 2%. Mass transfer coefficients in the fluid and solid phases were determined and were compared with previous data reported in the literature for low-scale rosemary supercritical extraction. A two-stage depressurization procedure was accomplished and the effect of both on-line fractionation and extraction time on the antioxidant activity of the samples collected was studied. The antioxidant activity of the different fractions could be straight correlated with the carnosic acid content with a regression coefficient of 0.92. [Copyright &y& Elsevier]

Abstract: Supercritical carbon dioxide was used as an extractive solvent to remove free fatty acids from cold-pressed olive oil. Crude oil of different acidity content (from 0.5 to 4.0wt%) was extracted in a packed column at 313K and pressures of 180, 234 and 250bar. The group contribution equation of state was employed to simulate the separation process, representing the oil as a simple pseudo-binary oleic acid+triolein mixture. Despite the simple representation of oil composition to simulate the deacidification process, a satisfactory agreement between the experimental and calculated yields and acidity of raffinates was obtained. The thermodynamic model was employed to study a continuous countercurrent multistage extraction process which yielded a raffinate having acidity lower than 0.7wt%, when crude olive oil with different FFA content was processed. [Copyright &y& Elsevier]