Preparation and Characterization of PVDF‐HFP Membrane

Poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) microporous membrane was prepared by supercritical CO₂ extraction of dibutyl phthalate (DBP) template from PVDF‐HFP/DBP film. The effects of extraction conditions such as pressure, temperature, and extraction time on extraction efficiency and the porosity of membrane were studied. The extraction efficiency of DBP and size stability of polymer membrane during extraction was compared with those of solvent extraction process. The structure of the resulting membrane was characterized by scanning electron microphotograph (SEM), X‐ray diffraction (XRD) and differential scanning calorimeter (DSC). With increasing the extraction temperature, pressure and time, the extraction efficiency and the porosity increased. Maximum extraction efficiency is obtained at extraction pressure and temperature higher than 18 MPa and 75°C, respectively. The porosity of membranes depended on the extraction efficiency and shrinkage ratio of membranes. Compared with solvent extraction, supercritical CO₂ extraction of the film generated the membrane with more uniform structure and higher porosity.     

Supercritical fluid extraction of grape seed oil and subsequent separation of free fatty acids by high-speed counter-current chromatography

Supercritical fluid extraction (SFE) of grape seed oil was performed to study the effect of various parameters such as pressure, temperature and the particle size of the sample on the yield and composition of oil using an analytical-scale SFE system. Then the extraction was scaled up by 125 times using a preparative SFE system under the optimized conditions of high pressure (30-40 MPa) and low temperature (35-40 degrees C) with medium particle size (20-40 mesh). The maximum yield of the oil can reach 6.2% with pure supercritical CO2 and 4.0% more oil can be obtained by adding 10% of ethanol as modifier. The unsaturated fatty acids (UFSs) make up about 70% in the oil on the basis of free fatty acids. The grape seed oil was then subjected to separation and purification for free fatty acids after saponification by high-speed counter-current chromatography coupled with evaporative light scattering detection (ELSD). The separation of 1.0 g of oil can yield about 430 mg pure linoleic acid at 99% purity. The fatty acids were analyzed by HPLC-ELSD.     

Ultrasonic extraction of anthocyanin from Clitoria ternatea flowers using response surface methodology

The ultrasonic extraction (UE) method of anthocyanin from Clitoria ternatea flowers using response surface methodology (RSM) was performed in this study. By using RSM, the objective is to optimise the extraction yield of anthocyanin from C. ternatea which is influenced by various factors, including the extraction temperature, time, ratio of solvent to solid and ultrasonic power. The empirical model was investigated by performing first-level optimisation in a two-level factorial design with Design Expert 7 software. In comparison with the conventional solvent extraction, UE showed a 246.48% better extraction yield and produced an anthocyanin extract with a radical scavenging activity of 68.48% at the optimised factors of 50°C, 150 min, 15 mL/g and 240 W.     

SFE of rosemary oil: Assessment of the influence of process variables and extract characterization

The effects of temperature and solvent density on the characteristics of the extracts obtained from supercritical fluid extraction (SFE) of the volatile compounds from Brazilian rosemary (Rosamarinus officianalis L., Labiatae) using carbon dioxide (CO₂) as solvent were investigated. The experiments were performed in a semi-batch laboratory scale home-made unit at two temperatures, viz. 310.15 and 320.15 K, over the pressure range of 100-160 bar. This study allowed to determine the crossover point and the maximum solubility of the oil. The products were analyzed by HRGC-MS, and compounds grouped in three different classes according to their molecular mass distribution in order to evaluate the influence of the variables studied on the characteristics of the extracts. The model proposed by Sovová was adopted in an attempt to interpret the mass transfer phenomena in the extraction process.     

Supercritical extraction of lycopene from tomato industrial wastes with ethane

Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO? and a near critical mixture of ethane and propane). The recovery of all-E-lycopene increased with pressure, decreased with the increase of the particle size in the initial stages of the extraction and was not practically affected by the solvent superficial velocity. The effect of the temperature was more complex. When the temperature increased from 40 to 60 °C the recovery of all-E-lycopene increased from 80 to 90%. However, for a further increase to 80 °C, the recovery remained almost the same, indicating that some E-Z isomerization could have occurred, as well as some degradation of lycopene. The recovery of all-E-lycopene was almost the same for feed samples with different all-E-lycopene content. Furthermore, when a batch with a higher all-E-lycopene content was used, supercritical ethane and a near critical mixture of ethane and propane showed to be better solvents than supercritical CO? leading to a faster extraction with a higher recovery of the carotenoid.     

Fast and non–derivative method based on high–performance liquid chromatography–charged aerosol detection for the determination of fatty acids from Agastache rugosa (Fisch. et Mey.) O. Ktze. seeds

This study utilised response surface methodology to optimise the conditions for the extraction of A. rugosa seeds oil (ARO). Single–factor experiment and response surface methodology (RSM) were performed to identify the extraction time, liquid–solid ratio and extraction temperature that provided the highest yield of ARO. The optimal extraction time, liquid–solid ratio and extraction temperature were 8 h, 4:1 mL/g and 55 °C. The fatty acids (FAs) content and oil yield obtained through the optimised impregnation–extraction process were 19.67 mg/g and 32.1%. These values matched well with the predicted values. Linolenic acid was identified to be the main active ingredient of ARO. The high–performance liquid chromatography–charged aerosol detection method presented here is fast and does not require derivatisation. Therefore, it could be used to quantitatively analyse the FAs present in ARO and applied to detect compounds with low or no ultraviolet response.     

Optimisation of steam distillation extraction oil from onion by response surface methodology and its chemical composition

Oil extraction from onion was performed by steam distillation. Response surface methodology was applied to evaluate the effects of ratio of water to raw material, extraction time, zymolysis temperature and distillation times on yield of onion oil. The maximum extraction yield (1.779‰) was obtained as following conditions: ratio of water to raw material was 1, extraction time was 2.5 h, zymolysis temperature was 36° and distillation time was 2.6 h. The experimental values agreed well with those predicted by regression model. The chemical composition of extracted onion oil under the optimum conditions was analysed by gas chromatography-mass spectrometry technology. The results showed that sulphur compounds, like alkanes, sulphide, alkenes, ester and alcohol, were the major components of onion oil.     

Supercritical Carbon Dioxide Extraction of Salidroside from Rhodiola rosea L var. rosea Root

Salidroside from the root of Rhodiola rosea L var. rosea was extracted by supercritical carbon dioxide with and without methanol as modifier. Three parameters, i.e. temperature, pressure and different concentrations of methanol were optimized. Salidroside determinations were carried out using high‐performance liquid chromatography (HPLC) with UV‐Vis detector. An experimental design of response surface methodology (RSM) was used to map the effect of pressure (at 200, 300 and 400 bar), temperature (at 50, 60 and 70 °C) and percentage of methanol modifier (at 80, 90 and 100%) on the extraction yield of the active compound and to determine the optimal conditions for the extraction of salidroside from the root of plant. The results showed that supercritical carbon dioxide failed to extract salidroside from the plant material without a methanol as modifier. The yield obtained after 1.5 h extraction with the rate of modifier 0.4 mL/min and 300 bar, 70 °C, and 80 percent of methanol modifier condition was the highest (17.15 mg/g). The optimum conditions were 70 °C, 295.49 bar and 80 percent of methanol as modifier with the yield of 16.17 mg/g. In addition, the yield obtained with supercritical fluid extraction (SFE) was compared with the Soxhlet extraction, whose yield was 8.64 mg/g.     

Effects of process parameters on supercritical CO2 extraction of total phenols from strawberry (Arbutus unedo L.) fruits: An optimization study

The aim of this work was to optimize total phenolic yield of Arbutus unedo fruits using supercritical fluid extraction. A Box–Behnken statistical design was used to evaluate the effect of various values of pressure (50–300 bar), temperature (30–80°C) and concentration of ethanol as co‐solvent (0–20%) by CO₂ flow rate of 15 g/min for 60 min. The most effective variable was co‐solvent ratio (p<0.005). Evaluative criteria for both dependent variables (total phenols and radical scavenging activity) in the model were assigned maximum. Optimum extraction conditions were elicited as 60 bar, 48°C and 19.7% yielding 25.72 mg gallic acid equivalent (GAE) total phenols/g extract and 99.9% radical scavenging capacity, which were higher than the values obtained by conventional water (24.89 mg/g; 83.8%) and ethanol (15.12 mg/g; 95.8%) extractions demonstrating challenges as a green separation process with improved product properties for industrial applications.     

Fabrication of Micron Level Particles of Amoxicillin by Rapid Expansion of Supercritical Solution

In this study, the rapid expansion of supercritical solution (RESS) process was used to precipitate fine solid particles of amoxiccilin where supercritical carbon dioxide was used as a solvent. The process has been done by changing the RESS parameters, including extraction pressure (150–210 bar), extraction temperature (313–333 K), nozzle length (2–15 mm), effective nozzle diameter (450–1700 µm), and spraying distance (1–10 cm), to investigate the effect of these parameters on the size and morphology of the precipitated amoxicillin particles. The characterization (size and morphology) of the particles was examined using scanning electron microscopy (SEM). Based on the different experimental conditions, the mean particle size of the fabricated particles were between 1.08 and 5.72 µm, while the intact particles of amoxicillin were about 41.46 µm. Also, no regular changes in the morphology of the processed particles were observed.     

Ultrahigh-pressure supercritical fluid extraction and chromatography of Moringa oleifera and Moringa peregrina seed lipids

An ultrahigh-pressure supercritical fluid extraction method was optimized and applied to extract seed oil lipids from two moringa species, namely Moringa oleifera (MO) and Moringa peregrina (MP). A full-factorial design was used to investigate the direct and interaction influence of pressure and temperature in the range of 40 to 80 MPa and 40 to 70 °C, respectively, on the extracted amount of oil from crushed seeds. The results revealed that pressure has a significant positive influence on the extracted amount of oil. The best extraction condition using neat CO₂ was found at 80 MPa and 57 °C, yielding 396 ± 23 and 529 ± 26 mg oil per gram of seeds for MO and MP, respectively. An extraction kinetics study revealed a mainly solubility-controlled extraction of oil, and 28 g of CO₂ was required to extract 400 mg of oil per gram of seeds of MO using the developed method. Addition of ethanol to the sample prior to the extraction increased the proportion of extractable polar lipids as well as the total amount of extracted oil. The developed method increased the extracted amount of oil twofold compared to a reference method based on solvent sonication. The obtained oil consisted mainly of glycerolipids, sterol esters, and phospholipids. Phospholipids, campesterol, and stigmasterol ester concentrations were found to be higher in MO while cholesterol ester was more abundant in MP.

     

Precipitation of Micronized Piroxicam Particles via RESS

In this study, the rapid expansion of supercritical solutions process was used to micronize the intact particles of piroxicam. Experiments were carried out to investigate the effect of extraction pressure (160–220 bar), extraction temperature (308–333 K), spraying distance (1–10 cm), and nozzle configuration (length and effective diameter) on the size and morphology of the precipitated piroxicam particle. The characterization of the particles was determined by scanning electron microscopy (SEM). The particle size of the original piroxicam particles was (39.2 µm) while depending upon the different experimental conditions, smaller particles of piroxicam (1.52–8.78 µm) were obtained.     

Supercritical fluid extraction of Moroccan (Timahdit) oil shale with water

Timahdit oil shale was subjected to supercritical water extraction. The results reveal significant difference in oil yields and composition when compared with those obtained from conventional pyrolysis. In addition, the effect of temperature and residence time on the supercritical water extraction of oil was investigated in a set of three experiments. The results revealed that the yield and the fraction of paraffins and aromatics increase while the percentage of asphaltenes decreases as the temperature is increased from 380 to 400°C. The residence time was found to affect the yield and the fraction of asphaltenes and polar compounds.     

Simulation and optimization of a supercritical extraction process for recovering provitamin A

In this work, a simulation procedure of a supercritical extraction process was developed through the use of the commercial simulator HYSYS^TM (Hyprotech Ltd.), adapting the existing units to the operating conditions typical of the supercritical extraction process. The objective is to recover provitamin A (β-carotene) from palm oil (esterified) using carbon dioxide/ethanol as the supercritical mixed solvent. This example characterizes the problem for recovering high added value product from natural sources, as the palm oil, which is desired by the market. Owing to the fact that esterified palm oil is a complex mixture, made by several components, in order to characterize this system in the simulator, it was necessary to create hypothetical components using the UNIFAC (universal function-group activity coefficients model) group contribution, because they are not present in a conventional database and, then, their physical properties must be estimated and/or predicted before the simulation. The optimization was carried out in each simulation for each equipment, in terms of operating conditions (temperature and pressure), in order to obtain the maximum recovery of carotenes. According to the results, it was possible to concentrate carotenes through two cycles of supercritical extraction with high yield. Furthermore, ethyl esters (biodiesel) were also obtained, as a byproduct of the proposed process, which can also be used as an alternative fuel, with the important characteristic that it is renewable.     

A novel application of microwave-assisted extraction of polyphenols from brewer’s spent grain with HPLC-DAD-MS analysis

This paper reports a novel application of microwave-assisted extraction (MAE) of polyphenols from brewer’s spent grains (BSG). A 2⁴ orthogonal composite design was used to obtain the optimal conditions of MAE. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the extraction yield of ferulic acid was investigated through response surface methodology. The results showed that the optimal conditions were 15 min extraction time, 100 °C extraction temperature, 20 mL of solvent, and maximum stirring speed. Under these conditions, the yield of ferulic acid was 1.31 ± 0.04% (w/w), which was fivefold higher than that obtained with conventional solid–liquid extraction techniques. The developed new extraction method considerably reduces extraction time, energy and solvent consumption, while generating fewer wastes. HPLC-DAD-MS analysis indicated that other hydroxycinnamic acids and several ferulic acid dehydrodimers, as well as one dehydrotrimer were also present, confirming that BSG is a valuable source of antioxidant compounds.     

Chemo-Enzymatic Epoxidation of <Emphasis Type="Italic">Lallemantia Iberica</Emphasis>Seed Oil: Process Development and Economic-Ecological Evaluation

The chemo-enzymatic epoxidation of Lallemantia iberica seed oil (LISO), a novel plant oil characterized by its exceptional high content of alpha-linolenic acid (>?60%), was developed using an immobilized lipase from Pseudozyma antarctica and hydrogen peroxide as oxidant. A statistical approach was used to study the effect of enzyme amount, temperature, time, and solvent amount on the oxirane oxygen content obtained during epoxidation. An oxirane oxygen content of 8.6 ± 0.2% corresponding to a yield of 82% was obtained under optimized conditions that were identified to be at an enzyme load of 8.2 g/mol of double bonds, a solvent amount of 56.4 wt.%, a temperature of 33 °C, and an incubation time of 17 h. In addition, the experimental investigation was combined with a techno-economic and ecological assessment gaining detailed information regarding cost structure and environmental impact for the chemo-enzymatic epoxidation of the novel plant oil.     

Extraction of essential oil from Pimpinella anisum using supercritical carbon dioxide and comparison with hydrodistillation

Supercritical fluid extraction (SFE) of essential oil from Pimpinella anisum, using carbon dioxide as a solvent is presented in this work. An orthogonal array design OA9 (3(4)) was applied to select the optimum extraction condition. The effects of pressure, temperature, dynamic extraction time and methanol volume on the extraction efficiency were investigated by the three-level orthogonal array design. Results show that pressure has a significant effect on the extraction efficiency. The extract obtained from P. anisum by using supercritical fluid extraction was compared with the essential oil obtained by hydrodistillation, considering both quantity and quality of the product. SFE products were found to be of markedly different composition, compared with the corresponding hydrodistilated oil. The total amount of extractable substances obtained in SFE (7.5%) is higher than that obtained by hydrodistillation (3.1%) and SFE is faster than hydrodistillation method.     

Cooling-Assisted Headspace Hollow Fiber-Based Liquid-Phase Microextraction Setup for Direct Determination of PAHs in Solid Samples by Using Volatile Solvents

To reinforce the extraction efficiency of the liquid- and solid-phase microextraction methods, different cooling-assisted setups have been employed, most of which are complicated, expensive, tedious, and do not show good performances due to indirect transfer of cold to the extraction phase. In this research, a simple, low-cost and effective cooling-assisted headspace hollow fiber-based liquid-phase microextraction (CA-HS-HF-LPME) device was fabricated and evaluated, which is able to directly cool down the extraction phase in different modes of LPME. It was coupled to GC-FID and utilized for the direct determination of PAHs in contaminated soil samples using volatile organic solvents. Different effective experimental variables including type and volume of extraction solvent, extraction time and temperature, and temperature of the cooled organic solvent were evaluated and optimized. Under the optimized experimental conditions (e.g., organic extracting solvent: 3 µL of acetone; extraction time: 20 min; extraction temperature: 90 °C; and temperature of cooled organic drop: −25 °C), good linearity of calibration curves (R ² > 0.99) was obtained in a concentration range of 1–10,000 ng g⁻¹. The limits of detection (LODs) were obtained over the range of 0.01–0.1 ng g⁻¹. The relative standard deviations (RSD%, n = 6) of 0.1 µg g⁻¹ PAHs were found to be 4.7–10.1 %. The CA-HS-HF-LPME-GC-FID method was successfully used for the direct determination of PAHs in contaminated soil and plant samples, with no sample manipulation. The results were in agreement with those obtained by a validated ultrasound-assisted solvent extraction (UA-SE) method.

     

In vivo antioxidant activity of Pinus koraiensis nut oil obtained by optimised supercritical carbon dioxide extraction

In this study, an orthogonal array design OA? (3?) was employed to optimise the conditions of supercritical carbon dioxide (SC-CO?) extraction of Pinus koraiensis nut oil. The effects of pressure, temperature and extraction time on the oil yield were investigated. Next, the fatty acid composition of the oil was examined by gas chromatography-mass spectrometry (GC-MS). The in vivo antioxidant activity of the oil was determined by estimating the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and the content of malondialdehyde (MDA) in rats fed with a high-fat diet. The results showed that extraction pressure and time were the main variables that influenced the oil yields. The optimal conditions with which to obtain highest yield of oil were determined to be 5760.83?psi, 50°C and 3.0?h (extraction yield was 458.5?g?kg?1); nine compounds, constituting about 99.98% of the total oil, were identified. The most abundant polyunsaturated fatty acids identified in the oil, linoleic acid and α-linolenic acid, constituted 41.79% and 15.62% of the oil, respectively. Moreover, the results on their antioxidant activities showed that the oil could improve the activities of SOD, GSH-Px and T-AOC, and reduce the content of MDA significantly, in the serum. These results indicate that P. koraiensis nut oil obtained by SC-CO? extraction had excellent antioxidant activities.     

Supercritical extraction of phloroglucinol and benzophenone derivatives from Hypericum carinatum: quantification and mathematical modeling

The aerial parts of Hypericum carinatum (Guttiferae) were extracted with supercritical carbon dioxide under constant temperature (40, 50 or 60°C) and gradual pressure increase (90, 120, 150 and 200 bar) aiming at the recovery of enriched fractions containing uliginosin B, cariphenone A and cariphenone B, compounds of pharmaceutical interest. The yields of these substances were determined by high‐performance liquid chromatography and compared with those obtained with n‐hexane maceration. The supercritical‐fluid extraction showed higher selectivity than the conventional solvent extraction method. After defining 40°C and 90 bar as the best conditions to obtain the target compounds, a mathematical model was used for the extraction process and a good correlation was achieved with the experimental data.