An evaluation of supercritical fluid extraction as an analytical tool to determine fat in canola,flax, solin,and mustard

Supercritical fluid extraction (SFE) with carbon dioxide was used to extract oil from soft oilseeds (flax, solin, canola, and mustard). Oil content determinations from the SFE method AOCS Am 3–96, with and without ethanol as a modifier, were compared to results obtained with an exhaustive extraction using petroleum ether (FOSFA as in AOCS Am 2–93). Without the modifier, oil recoveries using SFE were 10 to 15% lower than oil contents by the FOSFA method for the flax and canola samples. For mustard, the oil recoveries by SFE were about 20 to 30% lower than oil contents by the FOSFA method. In the presence of the modifier, oil recoveries for flax and canola were about 3% lower than the FOSFA recoveries. Varying the time, temperature, and amount of modifier (ethanol) showed that recoveries increased with time, pressure, temperature, and amount of modifier independently of the oilseeds tested. Kinetics of the SFE extraction showed that the oil recoveries increased with the extraction time and reached a plateau after 60 min. Multiple extractions (2×30 min), however, gave better recoveries than a single extraction for the same amount of time (60 min). The best results were obtained using multiple extractions without modifier or a combination of multiple extractions first without and then with 15% modifier. Under these last two conditions, oil recoveries were close to 100% for flax, solin, and canola, but mustard oil recoveries were still 10% lower than recoveries using the FOSFA method. Mustard samples gave the lowest oil recovery from SFE when compared to FOSFA method recoveries whatever conditions were tested, suggesting a matrix effect on the oil recovery. The acyl lipid content of the various extracts was studied using the sum of all FA expressed as TAG as a measure of acyl lipid extraction. The acyl lipid contents of the extracts were close to 100% when no modifier was used during the SFE. In the presence of modifier, the acyl lipid contents of the extracts were 10 to 15% lower than the results obtained without modifier. The amount of acyl lipid in the extract decreased as the quantity of modifier increased. This suggests that increasing the ethanol modifier increased the amount of polar compounds extracted without significantly increasing the total amount of lipids. The FA profiles were constant throughout the various extraction procedures.     

Determination of oil content in oilseeds by analytical supercritical fluid extraction

The total oil content of soyflakes, canola seed and wetmilled corn germ were determined by analytical supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent. Results obtained by SFE were in excellent agreement with those obtained by a conventional Soxhlet technique with organic solvents. The analytical-scale SFE technique yielded average means within one standard deviation of the means derived from the organic solvent-based methodology. Matrices containing both high and low oil content were successfully extracted with carbon dioxide at comparable precision to that obtained with the standard procedure. The supercritical fluid-based technique appears to be a suitable replacement for traditional extraction methods with organic solvents, thereby potentially eliminating the costs associated with solvent disposal and exposure of laboratory personnel to toxic and flammable solvents. Presented at the 4th International Symposium on Supercritical Fluid Chromatography and Extraction, Cincinnati, Ohio, May 20–22, 1992.     

Extraction of essential oil from geranium (Pelargonium graveolens) with supercritical carbon dioxide

This study investigated the supercritical fluid extraction (SFE) of geranium essential oil from geranium (Pelargonium graveolens) using supercritical carbon dioxide solvent. The extraction yield was measured as a function of pressure, temperature and carbon dioxide flow rate. At low pressure (10 MPa) and high temperature (343 K), waxes were co‐extracted with the essential oil, resulting in artificially elevated essential oil extraction yields as no method was available with the SFE apparatus used to separate co‐extracted waxes and oil. At high pressure (30 MPa) and low temperature (313 K), the amount of wax co‐extracted decreased. Under these ‘optimum’ conditions, the extraction yield increased with decrease in flow rate giving a maximum extraction yield of 2.53%. All samples were analyzed by gas chromatography–mass spectrometry and the effect of pressure and extraction time on oil composition was studied. The percentage compositions of terpene hydrocarbons, terpenols, geraniol and geranyl esters were significantly affected by pressure and extraction time. The oil samples obtained by SFE were also compared with commercially obtained steam distilled samples. All major components of the commercially obtained oils were present in the SFE‐obtained oils; however, the percentage composition of the major components differed greatly between steam distilled and SFE oils. Copyright © 2005 Society of Chemical Industry     

Enrichment,in vitro,and quantification study of antidiabetic compounds from neglected weed Mimosa pudica using supercritical CO2 and CO2-Soxhlet

Supercritical fluid extraction (SFE) using carbon dioxide (CO₂) and liquid CO₂ using Soxhlet (CO₂-Soxhlet) extraction were employed to extract three (3) antidiabetic compounds viz. stigmasterol, quercetin, and avicularin from Mimosa pudica. Various extraction parameters were studied. Extracts were analyzed pharmacologically, qualitatively and quantitatively to ascertain enrichment levels. All three antidiabetic compounds were effectively enriched under optimized conditions of temperature 60°C, pressure 40 MPa, co-solvent ratio 30%, and CO₂ flow rate of 5 ml min^?1. SFE was found to be the better method for enrichment of the antidiabetic compounds than the CO₂-Soxhlet method. Extraction conditions were seen to affect the enrichment of desired compounds.     

Application of gas anti-solvent process to the recovery of andrographolide from <Emphasis Type="Italic">Andrographis paniculatanees</Emphasis>

The gas anti-solvent (GAS) process was employed to extract andrographolide, which is the active ingredient found in Andrographis Paniculatanees, using carbon dioxide as an anti-solvent. The effects of temperature, flow rate and solvent type on the extraction recovery, particle size and morphology were investigated in this study. The experiments were conducted at the temperature ranging from 25–45 °C, carbon dioxide flow rate of 1–15 mL/min, and various types of organic solvents (methanol, ethanol, acetone and N,N-dimethylformamide). The extracted product was analyzed using high performance liquid chromatography (HPLC). The highest extraction yield was found to be 1.24 g andrographolide per 100 g of A. paniculata when using acetone as a solvent, carbon dioxide flow rate of 5 mL/min and the temperature of 35 °C. It was also found that no significant change in size or morphology of the precipitates was observed when changing temperature, carbon dioxide flow rate and solvents.     

Oilseed volatile analysis by supercritical fluid and thermal desorption methods

A knowledge of the volatile components present in an oil sample can provide important information relative to supercritical fluid extraction (SFE) process design, the current oxidative state of the oil, as well as the concentration and presence of important flavor volatiles in the oil. Volatile compounds from supercritical fluid-extracted oils were analyzed by headspace gas chromatography (GC) methods to determine if there were differences in the volatile profiles when two different methods of desorption were used. Canola, corn, soybean and sunflower seeds were extracted with supercritical carbon dioxide at 8000 psi and 50°C. Tenax porous polymer traps, attached at the exhaust port of the SFE apparatus, were utilized to collect the volatile components during the extractions. The volatile compounds on the Tenax trap were desorbed onto a GC column by both thermal and supercritical fluid techniques. Desorption temperature for the thermal method was 150°C, while conditions for the SFE technique were 50°C and 2000 psi. The lower-boiling volatiles from each oilseed were greater when desorbed by thermal means from the Tenax than by SFE; however, SFE desorbed the highermolecular weight compounds that were not removed by the thermal desorption method. Hexanal tended to be desorbed in comparable amounts by both methods. The SFE-based desorption technique provides a unique analysis method for the determination of both volatile and semivolatile compounds, as well as executing desorption under nonoxidative, low-temperature conditions that do not contribute to the degradation of lipid components.     

Effect of extraction methods on lipid yield and fatty acid composition of lipid classes containing γ-linolenic acid extracted from fungi

The effect of extraction procedures on the lipid yield and fatty acid composition of total lipid and main lipid structures (phospholipids, diacylglycerols, triacylglycerols, free fatty acids, and sterol esters) of fungal biomass (Mucor mucedo CCF-1384) containing γ-linolenic acid (GLA) was investigated. Seventeen extraction methods, divided into three groups, were tested: six with chloroform/methanol, five with hexane/alcohols, and six with common solvents or mixtures. The chloroform/methanol procedure (2∶1) was selected as standard, where lipid yield (TL/DCW, total lipid per dry cell weight) was 17.8%, considered to be 100% of lipids present. All chloroform/methanol extractions yielded more than 83% recorvey of lipids. Use of hexane/isopropanol solvent systems led to a maximum of 75% recovery. The best lipid yield was achieved by a two-step extraction with ethanol and hexane (120%). Extraction efficiency of the other solvent systems reached a maximum of 73%. Triacylglycerols were the main structures of lipid isolated; only methanol-extracted lipid contained 58.5% phospholipids. The fatty acid content of total recovered lipid was variable and depended on both the lipid class composition and the solvent system. GLA concentrations in total lipids isolated by hexane/alcohol procedures (7.3–10.7%) are comparable with classical chloroform/methanol systems (6.5–10.0%). The maximal GLA yield was obtained with chloroform/methanol/n-butanol/water/0.1 M ethylenediaminetetraacetic acid (EDTA) (2∶1∶1∶1∶0.1, by vol) and after two-step extraction with ethanol and hexane (14.3 and 13.7 g GLA/kg DCW, respectively). The highest GLA content was analyzed in the phospholipid fraction (16.1%) after using chloroform/methanol/n-butanol/water/0.1 M EDTA (2∶1∶1∶1∶0.1, by vol). Remarkably low concentrations of polyunsaturated fatty acids were determined in the free fatty acid fraction.     

Comparison of Supercritical Fluid Extraction and Liquid Solvent Extraction on Antitumor Diterpenoid from Pteris semipinnata L.

Extraction techniques using Supercritical Fluid Extraction (SFE) and Liquid Solvent Extraction (LSE) were evaluated for the extraction of Ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5 F), the antitumor diterpenoid from Pteris semipinnata L. The extracts were analyzed by high performance liquid chromatography (HPLC). SFE experiments showed that many factors had a great impact on the yield and purity of the diterpenoid, such as extraction temperature, pressure, fluid flow rate, extraction time, and modifier. For the SFE process, the optimum operation conditions were as follows: extraction temperature of 328.15 K, extraction pressure of 30 MPa, supercritical CO₂ flow rate of 160 kg/h, extraction time of 4 h, and 10% ethanol as the modifier. Under such a condition, the diterpenoid was almost completely extracted from the material and the yield was approximately 0.504 g/kg dry herb by HPLC analysis. The yield was approximately 3 fold higher than that by liquid solvent extraction. The purity of 5F was 5.148 g/kg dried extract with SFE, it was about 9 fold higher than that by LSE. Mass spectrum data indicated there were two correlative compounds, 5F and its derivative with glycose, in both the extracts, and the ratio of the signal strength of 5F and its derivative was about 3:1 in the SFE extract while that ratio was 1:3 in the LSE extract. The results demonstrated that the supercritical fluid extraction was selective, highly efficient, and with less consumption of organic solvents.     

Quantitative extraction of pecan oil from small samples with supercritical carbon dioxide

A procedure to determine total oil content of pecan was developed for samples weighing 500 and 10 mg by supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent, and chilled hexane as the trapping solvent. Fatty acid methyl esters (FAMEs) were prepared from the total lipid fraction by using either an aliquot (500 mg starting weight) or the entire extract (10 mg starting weight). Total oil content obtained for either sample size with SFE was similar to that obtained with an organic solvent extraction technique. The fatty acid composition for the total lipid fraction of oils extracted with SFE was the same as for oils extracted with organic solvents, and oil composition did not change during SFE. Both oil yield and fatty acid composition were similar to those reported previously for pecan. Samples could be extracted and placed into FAME-derivatizing reagents in one day, and fatty acid composition of the total lipid fraction could be determined by gas-liquid chromatography the next day. The procedure, as demonstrated for pecan, should be suitable for other oilseeds, especially those containing low amounts of water.     

Extraction of the essential oil of abajeru (Chrysobalanus icaco) using supercritical CO2

Abajeru (Chrysobalanus icaco) is a plant that has hypoglycemic properties and is often used in Brazilian popular medicine. In order to identify the flavoring and hypoglycemic substances present in this plant, this work has an objective for the extraction of the essential oil presented in the leaves of abajeru using the supercritical fluid extraction (SFE). The supercritical solvent used is CO₂, because of its moderate critical temperature and pressure, atoxicity, low cost and volatility. The experiments were conducted using dried leaves in an apparatus containing a high-pressure pump, a stainless steel extractor of 42 mL of volume and a micrometric valve for sampling. Different operational conditions were tested, varying mainly the temperature (313.15-353.15 K) and the pressure (10.5-20 kPa) in order to investigate the efficiency of the process. The results showed that the best operational condition was at 20 kPa and 353.15 K. To compare the supercritical carbon dioxide results, the essential oil was also extracted by hydrodistillation and soxhlet, using ethanol as solvent. The chromatographic analysis showed that the different technologies studied extracted the same classes of compounds but the SFE obtained the extract with potential hypoglycemic activity with the presence of lupenol.     

Optimization of an Oil Extraction Process for Algae from the Treatment of Manure Effluent

Increasing interest in the coupling of biological wastewater treatment processes with the generation of value-added products (such as oil containing ω-3 fatty acids (FA)) has stimulated efforts in adapting extraction methods for treatment byproducts. This study’s objective was to compare a high temperature/pressure extraction method (accelerated solvent extraction) (ASE) and a manual extraction method (modified Folch extraction) with regard to their ability to extract total oil from three algae samples from the treatment of dairy manure effluent. The efficiency of total oil and FA extraction with three solvents (chloroform/methanol, isopropanol/hexane, and hexane) was also evaluated using the ASE method. Results showed that the ASE method yielded higher values for total oil content compared to the Folch method but similar values for FA content and composition after four extraction cycles with chloroform/methanol. However, the ASE method yielded much higher amounts of FA in the first cycle (85–95% of total extracted) compared to the Folch method (44–55% of total extracted in the first cycle). As expected, the extraction efficiency of the ASE method for FA was dependent on the extraction solvent. FA content values using ASE with chloroform/methanol > isopropanol/hexane > hexane. FA content values using the Folch method or ASE with chloroform/methanol were not significantly influenced by sample particle size within the size range of 0.1–1 mm.     

Supercritical CO2 extraction of rice bran

Extraction of rice bran lipids with supercritical carbon dioxide (SC-CO₂) was performed. To investigate the pressure effect on extraction yield, two isobaric conditions, 7000 and 9000 psi, were selected. A Soxhlet extraction with hexane (modified AOCS method Aa 4–38; 4 h at 69°C) was also conducted and used as the comparison basis. Rice bran with a moisture content of 6%, 90% passable through a sieve with 0.297 mm opening, was used for extraction. A maximum rice bran oil (RBO) yield of 20.5%, which represents 99+% lipid recovery, was obtained with hexane. RBO yield with SC-CO₂ ranged between 19.2 and 20.4%. RBO yield increased with temperature at isobaric conditions. At the 80°C isotherm, an increase in RBO yield was obtained with an increase in pressure. The pressure effect may be attributed to the increase in SC-CO₂ density, which is closely related to the value of the Hildebrand solubility parameter. RBO extracted with SC-CO₂ had a far superior color quality when compared with hexane-extracted RBO. The level of sterols in SC-CO₂-extracted RBO increased with pressure and temperature.     

Optimization of supercritical fluid extraction of linseed oil using RSM

The objective of the present study was to develop a supercritical fluid extraction (SFE) method, suitable for extraction of total oil content from linseed, and to be used as a preparative technique for fatty acid determination. Optimum conditions (volume of added ethanol as a co‐solvent, dynamic extraction time (DET), and pressure) were predicted in order to obtain the maximum yield of the extract. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used for modeling the process. Variable values ranged as follows: co‐solvent 0–1 mL, DET 36–60 min, and pressure 45.57–62.05 MPa (6000–9000 psi). Effects of co‐solvent volume and extraction pressure were well described by simplified polynomial equation (R² = 0.85), since DET had no significant influence (p>0.05) on the extract yield. The maximum yield of oil, calculated from experimental results, was obtained with 1 mL of co‐solvent, and pressure of 62.05 MPa. Optimized conditions were used for extraction of oil from four samples of linseed, ground to pass through 1, 2, 3, and 4 mm‐sieve, to determine adequate granulation for SFE. Finally, results for yield and fatty acid composition of the extract obtained using SFE were compared with the results of Soxhlet extraction. Practical applications: The obtained extracts can be used for fatty acid analysis, since they have not been damaged and their fatty acid compositions have not been degraded by reagents or aggressive extraction conditions. It is shown that the selection of appropriate milling equipment for grinding of samples is necessary to achieve adequate granulation and avoid fractionation of sample.     

Selectivity of Supercritical CO<Subscript>2 </Subscript>in the Fractionation of Hake Liver Oil Ethyl Esters

The solubility of different ethyl esters derivatized from hake liver oil in supercritical carbon dioxide was studied. A selectivity factor was used to determine optimal conditions to fractionate the ethyl ester mixture. A strong influence of solvent pressure and temperature was observed within 8.63–18.04 MPa and 40–70 °C. The lowest total solubility of the ethyl ester mixture was obtained when using supercritical carbon dioxide at the lowest density (the lowest pressure and the highest temperatures value tested). The highest discrimination against long-chain polyunsaturated fatty acids (e.g. EPA and DHA) was also obtained at these above conditions. Conversely, higher solubility and lower selectivity were obtained when solvent density increased. Considering this inverse correlation between selectivity and solubility, a single-step batch-fractionation process was designed to increase the 22:6 ethyl ester content from an initial value of 17.5% in the starting material to 55% in the final extract.     

八角茴香油的提取工艺和香气性能

以八角茴香果为原料,比较了超临界CO2流体萃取法(SFE)和水蒸气蒸馏法(SD)对八角茴香油的提取率和香气性能的影响。用正交设计方法,确定了超临界CO2流体萃取八角茴香油的最佳条件为:萃取压力13.8MPa,萃取温度40℃,萃取时间2 h。在该条件下,八角茴香油的萃取率为2.88%。相同的萃取条件下,用水蒸气蒸馏技术提取八角茴香油,精油萃取率为1.39%。通过气味指纹分析仪(电子鼻)检测和气味感官评定,对两种提取方法得到的八角茴香油的香气性能进行了比较,用SFE法所得八角茴香油的质量比SD法所得精油有明显改善,香气更完全,更具新鲜感和天然感。     

Extraction and characterization ofDimorphotheca pluvialis seed oil

Dimorphotheca pluvialis is increasingly recognized as an interesting industrial new oilseed crop because it contains up to 60% of the unusual fatty acid dimorphecolic acid (9-hydroxy,10t,12t-18∶2) (DA) for which new applications are being developed. In this paper, the yield, composition and quality are evaluated for dimorphotheca oils (DMO) which were recovered by pressing, conventional solvent extraction and supercritical carbon dioxide extraction (SCE). Mechanical pressing of the seeds required high temperatures and resulted in an oil recovery of only 40%, whereas the extraction protocols yielded more than 95%. Oil recovery by pressing of winged seed was even more difficult than that of unwinged seeds; hence, solvent extraction of winged seeds was preferred. The dark-colored DMO, recovered by expelling or by extraction with organic solvents, needed further refining to remove pigments and gums, whereas the light yellow-colored SCE DMO did not require further refining. SCE oil had a low phospholipid content (11 mg P/kg). Pressed oil (95 mg P/kg) and hexaneor pentane-extracted DMO (200 mgP/kg) had much higher phospholipid contents. Peroxide andp-anisidine values were low for freshly recovered oils, but increased after storage, especially in the SCE oil, due to the low concentration of natural antioxidants in SCE DMO, such as tocopherols. The DA content of the oils recovered by the various techniques showed only minor differences, except that supercritical carbon dioxide had slightly decreased solubilizing power for tri- and di-dimorphecolin as compared to hexane and pentane.     

Supercritical Fluid Extraction Coupled with Solvent-Less Spray Collection Mode for Rapid Separation of Indirubin and Tryptanthrin from Folium Isatidis

Supercritical carbon dioxide modified with acetonitrile and water for the extraction of indirubin and tryptanthrin from Folium Isatidis and the collection of these two bioactive ingredients by a spray mode are presented in this study. Two pumps, one for the addition of the modifier and the other for the transportation of CO₂, were used for supercritical fluid extraction (SFE). This is a fast and environmentally-friendly approach for the production of herbal medicine. Compared to conventional solvent extraction, the yield of bioactive indirubin and tryptanthrin by this SFE process was approximately the same, but with a shorter process time and better protection of the environment.     

An improved micro-extraction cell for supercritical fluid extraction and chromatography of fatty acids

An improved supercritical fluid micro-extraction cell of increased reliability was designed for on-line supercritical fluid extraction and chromatography (SFE/SFC) of food and other lipid-related samples. The key components in the modified cell include a Swagelok stainless steel reducing union with a dual ferrule as the cell, with polyetherether-ketone (PEEK) ferrules and nuts to connect the cell to the control valve. The new cell did not leak under all conditions examined (100–500 atmospheres, 40–80°C), even after numerous extractions (>250). The quantitative performance of the cell was evaluated with fatty acid standard solutions, technical grade fatty acid sources and wheat flour. The percent relative error (%RE) for the fatty acid standards and technical-grade fatty acid samples was ≤6.0% for oleic, linoleic and linolenic acid. The %RE for oleic and linoleic acid in the whole-wheat samples was ≤10%. The results demonstrate that the new extraction cell can be used for quantitative extractions and that the sensitivity of the SFE/SFC technique is excellent. Similar SFE/SFC methods could prove useful in studying the interaction of free fatty acids with various food components such as enzymes, amylose and proteins.     

Influence of operating variables on yield and quality parameters of olive husk oil extracted with supercritical carbon dioxide

Supercritical fluid extraction is a viable alternative process for extracting oil from olive husk, a residue obtained in the olive oil production. We analyzed the effects of pressure (P) (100–300 bar), temperature (T) (40–60°C), solvent flow (1–1.5 L/min), and particle size (D) (0.30–0.55 mm) on extraction yield, and three oil-quality parameters: acidity (OA), PV, and phosphorus content (PC). A response surface methodology based on the statistical analysis of the experimental data permitted us to obtain mathematical expressions relating the operational variables and parameters studied. At the best extraction condition of the experimental range analyzed (P=300 bar, T=60°C, D=0.30 mm, and solvent flow=1.25 L/min at standard conditions), the oil yield was 80% (w/w) with respect to hexane extraction, whereas the quality parameters OA, PV, and PC were 14% (w/w), 8 meq/kg, and 2.3·10⁻³% (w/w), respectively. These results were compared to those obtained by hexane Soxhlet extraction. The quality of the supercritical extract was superior, requiring only simple refining. This advantage may result in improved economics of the supercritical process in relation to the conventional extraction with hexane.     

Effect of operating conditions on catechin extraction from betel nuts using supercritical CO2-methanol extraction

In this work, the effect of extraction parameters on catechin extraction from betel nuts was studied. The supercritical carbon dioxide extraction parameters were pressure, temperature, and solvent flow rate while using average particle size of 177.5 μm and 5% (v/v) methanol as modifiers. Detection and quantification of catechin were achieved using HPLC analysis. The highest amount of extract and catechin concentration were 34.00 mg extract/g sample and 565.38 ppm of catechin obtained at 30 MPa, 70°C, and 4 mL/min. The results given by optimization tools suggest the same operating conditions with less than 3% difference.