Supercritical Fluid Solvents Research Articles

Comprehensive analysis of oils and remaining solid matrices from supercritical fluid extraction of salmon side streams: Fatty acids, bioactive peptides, minerals, and heavy metals

Atlantic salmon (Salmo salar) side streams (head, backbone, and viscera) are nutrient-rich and offer potential for valorization. This study evaluates supercritical fluid extraction (SFE) and solvent extraction (SE) methods for recovering oils, fatty acids, bioactive peptides, minerals, heavy metals, and antioxidants from these byproducts. Both the oil and the remaining solid resulting from the extraction process were analyzed. SFE was more effective in extracting fatty acids from heads and backbones. However, SE yielded a higher peptide content, with SE backbone solids containing 281 peptides, and SE viscera and heads containing 220 peptides each. In contrast, SFE-derived solids had significantly fewer peptides: 9 in heads, 129 in backbones, and 130 in viscera. The identified peptides exhibit potential functional properties, including antioxidant, anti-inflammatory, antithrombotic, immunomodulating, anticancer, and hypolipidemic effects. Mineral and heavy metal content in all extracts met safety standards. SFE-derived matrices had the highest calcium levels (49.7 mg/g in heads, 24.2 mg/g in backbones) and lower heavy metal concentrations than SE. Arsenic, cadmium, mercury, and lead levels were 1.8 mg/kg, 1.8 μg/kg, 55.0 μg/kg, and 25.7 μg/kg, respectively, for SFE, compared to SE's higher values (e.g., 3.5 mg/kg for arsenic). Both methods produced extracts with promising antioxidant activity.

Evaluation of Moringa oleifera seed oil extracted with different extraction methods

Moringa seed oil composition extracted with different methods such as supercritical fluid extraction (SFE), soxhlet extraction (SOXE) and solvent extraction (SE) was evaluated and compared. The oil yield obtained by SFE, SE and SOXE was 25.25, 27.53 and 29.81%, respectively. There were slightly significant differences among SFE, SOXE and SE oils in their refractive indices, peroxide values, tocopherols, carotenoids, β-sitosterol and campesterol contents. However, SOXE and SE oils showed no significant differences in their TBA, unsaponifiable matter, phenols, flavonoids, oxidative stability, oleic acid, stigmasterol, Δ7- avenasterol and Δ5-avenasterol contents. Furthermore, SFE oil showed significantly higher unsaponifiable matter, phenols, flavonoids, tocopherols, carotenoids, oleic acid, unsaturated fatty acids to saturated fatty acids ratio, sterols contents and oxidative stability. The high content of tocopherol, phenols, and flavonoids of the Moringa oils could be attributed to the higher resistance to oxidation, especially extracted by SFE. These results promote the use of SFE for the extraction of high quality Moringa oil. extraction of high quality.

Towards a Greener Approach for Biomass Valorization: Integration of Supercritical Fluid and Deep Eutectic Solvents.

A green and sustainable procedure for obtaining Lavandula stoechas extracts with antioxidant and antimicrobial properties was investigated. Green solvents, supercritical CO2, and natural deep eutectic solvents (NADES) together with ultrasound-assisted extraction were used for the sequential extraction of terpene and polyphenols fractions. After the CO2 extraction of the terpene fraction, the residue material was used in an extraction with different NADES (betaine-ethylene glycol (Bet:EG), betaine-glycerol (Bet:Gly), and glycerol-glucose (Gly:Glu)), intensified with an ultrasound-assisted method (at 30 and 60 °C). In the CO2 extract, the major group of components belonged to oxygenated monoterpenes, while the highest polyphenol content with the dominant rutin (438.93 ± 4.60 µg/mL) was determined in Bet:EG extracts (60 °C). Bet:EG extracts also exhibited the most potent antioxidant activity according to DPPH, ABTS, and FRAP assays. Moreover, Bet:EG extracts showed significant inhibitory activity against Gram-positive and Gram-negative bacteria, with minimum inhibitory activity of 0.781-3.125 and 1.563-6.250 mg·mL-1, respectively. By comparing the polyphenolic content and antioxidant and antimicrobial activities of Bet:EG extracts with extracts obtained with conventional solvents (water and ethanol), the superiority of NADES was determined. The established environmentally friendly procedure unifies the requirements of green and sustainable development and modern pharmacognosy because it combines the use of safe alternative solvents, the absence of solvent waste generation, more rational use of resources, and the attainment of safe and quality extracts.

Towards a greener approach for biomass valorization: Integration of supercritical fluid and deep eutectic solvents

Towards a greener approach for biomass valorization: Integration of supercritical fluid and deep eutectic solvents

Ultrasound assisted extraction of oils from apple seeds: A comparative study with supercritical fluid and conventional solvent extraction

The aim of this study was to optimize the processing conditions for the extraction of apple seed oil by applying ultrasounds (UAE) using hexane as solvent. A response surface methodology with a central composite design identified the following optimized parameters: 56 W of power (64% amplitude), 30 min at 30 °C. The obtained oil presented a fatty acids profile rich in linoleic acid (35.5 ± 2.8 g/100 g) with an antioxidant activity equal to 0.22 ± 0.1 mg Trolox/g oil and a total phenolic content of 0.16 ± 0.1 mg GAE/o oil. The chemical characteristics of the UAE oil were then compared with those obtained for the oils extracted with Soxhlet (SE) and supercritical fluid (SFE). UAE gave similar yields (17.20 ± 2.3%) compared to SFE (19.3 ± 2.1%), and SE (19.1 ± 1.5%). Fatty acid profiles were also not significantly different (p < 0.05). The UAE oil was richer in antioxidants like phloretin and phloridzin. Amygdalin was detected in UAE and SE oils but not in SFE oil. The comparison among the processes showed that the UAE was a more efficient and time-saving technique, while SFE was able to provide an oil free from amygdalin suitable for possible further food applications.

Quality comparison of camellia (Camellia oleifera C.Abel) seed oil with different extraction methods

The quality of camellia seed oil (CSO) varies with the oil extraction methods. In the present work, the oil yield, physicochemical properties, bioactive compounds, fatty acid composition, and Fourier transform infrared spectra of CSOs prepared by supercritical fluid, aqueous, pressing, and solvent extraction were explored systematically. Additionally, the microstructure of camellia seed cake after oil extraction was observed by scanning electron microscopy. Results showed that supercritical fluid extraction had the highest oil yield (92.42%), and the extracted oil was also superior to the other methods in the contents of polyphenol, β-sitosterol, and squalene, which were 89.34, 3173.23, and 6.20 mg/kg, respectively. Moreover, CSO extracted by supercritical fluid extraction had lower peroxide value and better colour indexes. In terms of fatty acid composition, CSOs extracted by supercritical fluid, pressing, and solvent extraction were similar, while CSO extracted by aqueous extraction had higher saturated fatty acid contents and lower unsaturated fatty acid contents than the other samples. Fourier transform infrared spectra analysis showed that the extraction methods had no significant effect on the chemical functional groups of CSOs. Scanning electron microscopy revealed that supercritical fluid extraction and solvent extraction could more effectively promote the release of oil from camellia seeds. In general, the quality of CSOs extracted by different methods had significant differences, and supercritical fluid extraction could be a promising extraction method for CSO.

Effective Utilization of Pineapple Waste

India is the largest fruit and vegetable producer. Until fruit is eaten, fruit peel stays waste. Phenolic acids, ascorbic acid, β-carotenes, and flavonoids are the most bioactive components of pineapples. This is one of the secondary plant metabolites abundantly present in pineapple skins in this sample, ferulic acid. Ferulic acid is a low-toxic phenolic acid widely used in diet and cosmetics. Ferulic acid is extracted using different conventional and non-conventional methods such as Soxhlet extraction, Supercritical fluid extraction and Solvent extraction and the amount of ferulic acid is quantified using High performance liquid chromatography (HPLC). The study also evaluated the presence of total phenolic content (Gallic acid equivalent/GAE)and antioxidant activity. Soxhlet extraction using methanol and petroleum ether was the best solvent, methanol showed maximum ferulic acid concentration (0.7696 g/100g), phenolic content (2.365 mg g/GAE), antioxidant activity (45%) and percentage yield (90.5% mg). This study also analysed micronutrients such as vitamins (A, B, B1, B2, B6, B12 and C), calcium, potassium, phosphorus, iron, manganese, zinc and dietary fibre in the pineapple peel

Determination of multi-class antibiotic residues in compost by microwave-enhanced accelerated solvent extraction and ultra performance convergence chromatography with tandem mass spectrometry.

This work reports the development and application of a multi-class compound analysis method for the determination of 20 antibiotic residues in compost. Samples were processed by microwave-enhanced accelerated solvent extraction at 120°C for 7.5min. Salting-out homogeneous liquid-liquid extraction was used to remove water and water-soluble impurities from the extract before ultra performance convergence chromatography with tandem mass spectrometry analysis. By using the supercritical fluid (carbon dioxide) and organic solvent (methanol) as the mobile phase, the 20 antibiotics and the internal standard were well separated in 8.2 min without obvious matrix effect. Method validation was performed and good trueness (relative error in the range of ±5.0%) and precision (inter- and intraday relative standard deviations<10.8%) were obtained. Method detection and quantitation limits were 0.8-1.9 and 2.7-7.1ng/g, respectively. Recoveries were assessed at three concentration levels (10, 60, and 400ng/g) and acceptable mean values (70.4-111.9%) were found. This method has also been used to analyze real samples, and the average concentrations of antibiotics (excepting the concentrations<method quantitation limits) were determined up to 123.6ng/g. The results showed the method could be helpful for the analysis of multi-class antibiotics in environmental samples.

Supercritical Fluid Extraction of Berry Seeds: Chemical Composition and Antioxidant Activity

The influence of supercritical fluid extraction (SFE) and solvent extraction of oils from cloudberry, bilberry, and black currant seeds on the yield, chemical properties, and recovery of antioxidant compounds was investigated. SFE was performed for 1 h at 350 bar and at 50°C and 80°C. Fatty acids, vitamin E, carotenoids, and free radical-scavenging activity (DPPH) were assayed. SFE at 80°C resulted in higher oil yields for cloudberry and black currant seeds. The oils were rich in polyunsaturated fatty acids (PUFAs) (66.8%–75.9% w/w), with high percentages of linoleic and α-linolenic acids. The black currant seed extracts had the highest concentrations of vitamin E (range, 113.0–241.8 mg/100 g oil) and carotenoids (range, 11.5–32.3 mg/100 g oil) and the highest antioxidant activity. The cloudberry seed oils also had high antioxidant content and activity. These findings indicate the potential of SFE for the recovery of PUFA and antioxidant compounds in berry by-products.

A review of microencapsulation methods for food antioxidants: Principles, advantages, drawbacks and applications

Bioactivities and numerous health benefits against a number of oxidative stress related diseases have been attributed to the role of dietary antioxidants. The development of physical (spray drying, lyophilization, supercritical fluid precipitation and solvent evaporation), physico-chemical (coacervation, liposomes and ionic gelation) and chemical encapsulation techniques (interfacial polymerization and molecular inclusion complexation) enable to obtain healthier and acceptable bioactive compounds. This review focuses on the impacts of microencapsulation techniques on the encapsulation characteristics of food antioxidants. Additionally, this study also provides detailed information on the principles, effective parameters, advantages, disadvantages and applications of microencapsulation techniques.

Phase behaviors for the poly(2-phenylethyl methacrylate) in supercritical fluid solvents: Experiment and PC-SAFT EoS

In this work, the experimental cloud-points in the binary and ternary mixtures for poly(2-phenylethyl methacrylate) [P(2-PEMA)] solutions containing supercritical solvents (i.e., carbon dioxide, propylene, 1-butene, dimethyl ether (DME)) are carried out up to 473K and 224MPa. According to the amount of cosolvent (i.e., DME), the cloud-point curves for ternary mixtures of P(2-PEMA) in supercritical solvents (i.e., carbon dioxide, propylene, 1-butene) show the changes from upper critical solution temperature (UCST) behavior to lower critical solution temperature (LCST) behavior. The PC-SAFT equation of state is applied to correlate the phase behaviors of all experimental systems, and the calculated results are shown as a reasonable agreement with experimental data. According to the amount of DME (i.e., cosolvent), the UCST- and LCST-type phase behaviors are described exactly by PC-SAFT EoS with one adjustable binary interaction parameter on which the effect of temperature and/or cosolvent amount is not considered.

Supercritical fluid extraction of Rumex Acetosa L. roots: Yield, composition, kinetics, bioactive evaluation and comparison with conventional techniques

In this study, Rumex Acetosa extracts were obtained from extraction techniques with supercritical fluid (SFE), Soxhlet and low pressure solvent extraction (LPSE). In the SFE, it was evaluated the effect of the process variables (temperature, solvent flow rate, pressure and cosolvent concentration) on the extraction kinetics, yield and extract solubility. In the Soxhlet extraction, it was evaluated the usage of ethanol, acetonitrile, isopropanol and tert-butyl alcohol, while in LPSE extraction, it was used ethanol as solvent. The phenolics total content (TPC), antioxidant capacity (IC50) and extract composition were determined. The yield obtained ranged from 0.2 to 8.3%. The SFE extraction has demonstrated great efficiency in the extraction of phenolic compounds (anthraquinone and stilbene). The trans-resveratrol concentration in the extracts ranged between 1.03 and 3.52mg/g, depending on the technique used, the values of IC50 and TPC ranges from ​ 10.67 to 163.43μg/mL and 27.63 to 157.04 mgEAG/g, respectively.

Impregnation of polymers with 2,2,6,6-tetramethyl-4-oxo-piperidine-1-oxyl (TEMPONE) paramagnetic probe in sub- and supercritical CO2

The spin probe method is used to study the impregnation of polycarbonate (PC) based on bisphenol A, polyethylene oxide (PEO), and crosslinked acrylamide–acrylic acid copolymer (PAA) with organic molecules in sub- and supercritical CO2 media. Electron spin resonance (EPR) data show that, at 196 bar and 307 K, 2,2,6,6-tetramethyl-4-oxo-piperidine-1-oxyl (TEMPONE) paramagnetic spin probe molecules penetrate into the PC and PEO matrices, which are, respectively, in the glassy and elastic states under normal conditions. The degree of impregnation of PAA under these conditions is negligibly small. Estimates of the local concentration of probe molecules show that, in the PEO matrix, TEMPONE is distributed much more uniformly than in the PC matrix. Analysis of the effect of temperature on the shape of the EPR spectra of the radical in the polymer matrix shows that, under the same conditions, the mobility of TEMPONE molecules in the PEO matrix is much higher than in the PC matrix. The results suggest that the spin probe method is promising for studying the characteristics of macro- and micro-processes in polymer–supercritical fluid solvent–organic molecule ternary systems.

Molecular simulation of CO chemisorption on Co(0001) in presence of supercritical fluid solvent: A potential of mean force study.

For several decades, heterogeneous catalytic processes have been improved through utilizing supercritical fluids (SCFs) as solvents. While numerous experimental studies have been established across a range of chemistries, such as oxidation, pyrolysis, amination, and Fischer-Tropsch synthesis, still there is little fundamental, molecular-level information regarding the role of the SCF on elementary heterogeneous catalytic steps. In this study, the influence of hexane solvent on the adsorption of carbon monoxide on Co(0001), as the first step in the reaction mechanism of many processes involving syngas conversion, is probed. Simulations are performed at various bulk hexane densities, ranging from ideal gas conditions (no SCF hexane) to various near- and super-critical hexane densities. For this purpose, both density functional theory and molecular dynamics simulations are employed to determine the adsorption energy and free energy change during CO chemisorption. Potential of mean force calculations, utilizing umbrella sampling and the weighted histogram analysis method, provide the first commentary on SCF solvent effects on the energetic aspects of the chemisorption process. Simulation results indicate an enhanced stability of CO adsorption on the catalyst surface in the presence of supercritical hexane within the reduced pressure range of 1.0-1.5 at a constant temperature of 523 K. Furthermore, it is shown that the maximum stability of CO in the adsorbed state as a function of supercritical hexane density at 523 K nearly coincides with the maximum isothermal compressibility of bulk hexane at this temperature.

Comparison between several techniques of olive tree bark extraction (Tunisian Chemlali variety)

In order to better understand the chemical composition of the olive tree bark of Tunisian chemlali variety (Olea europaea cv. ‘Chemlali’), this material was extracted by different ways. Compositions of extracts were used at best-selected conditions for each technique, and characterised using HPLC, LC/MS and GC–MS techniques. Analyses are conducted to an important variety of high carbon number compounds such as aliphatic compounds as nanocosane and heptacosane, and molecules with high value added tax (VAT) which can be classified as follows: diterpenes as phytol, triterpenes as squalene and also esters as Benzyl cinnamate. Hydrodistillation at high pressure seems to be a very common method to get a wide variety of compounds, the results are better than the ones obtained using supercritical fluid extraction and solvent extraction.

Effect of solvent type and ratio on betacyanins and antioxidant activity of extracts from Hylocereus polyrhizus flesh and peel by supercritical fluid extraction and solvent extraction

The main objective of the present study was to investigate the effect of solvent type and ratio as well as the extraction techniques (i.e. supercritical fluid extraction (SFE) and conventional solvent extraction) on betacyanins and antioxidant activity of the peel and fresh extract from the red pitaya (Hylocereus polyrhizus). The peel and flesh extracts obtained by SFE at 25MPa pressure and 10% EtOH/water (v/v) mixture as a co-solvent contained 24.58 and 91.27mg/100ml total betacyanin, respectively; while the most desirable solvent extraction process resulted in a relatively higher total betacyanin in the peel and flesh extracts (28.44 and 120.28mg/100ml, respectively). The major betacyanins identified in the pitaya peel and flesh extracts were betanin, isobetanin, phyllocactin, butyrylbetanin, isophyllocactin and iso-butyrylbetanin. The flesh extract had the stronger antioxidant activity than the peel extract when the higher proportion of ethanol to water (E/W) was applied for the extraction.

Supercritical Fluid Technologies to Fabricate Proliposomes.

Proliposomes are stable drug carrier systems designed to form liposomes upon addition of an aqueous phase. In this review, current trends in the use of supercritical fluid (SCF) technologies to prepare proliposomes are discussed. SCF methods are used in pharmaceutical research and industry to address limitations associated with conventional methods of pro/liposome fabrication. The SCF solvent methods of proliposome preparation are eco-friendly (known as green technology) and, along with the SCF anti-solvent methods, could be advantageous over conventional methods; enabling better design of particle morphology (size and shape). The major hurdles of SCF methods include poor scalability to industrial manufacturing which may result in variable particle characteristics. In the case of SCF anti-solvent methods, another hurdle is the reliance on organic solvents. However, the amount of solvent required is typically less than that used by the conventional methods. Another hurdle is that most of the SCF methods used have complicated manufacturing processes, although once the setup has been completed, SCF technologies offer a single-step process in the preparation of proliposomes compared to the multiple steps required by many other methods. Furthermore, there is limited research into how proliposomes will be converted into liposomes for the end-user, and how such a product can be prepared reproducibly in terms of vesicle size and drug loading. These hurdles must be overcome and with more research, SCF methods, especially where the SCF acts as a solvent, have the potential to offer a strong alternative to the conventional methods to prepare proliposomes.

Supercritical Fluid Extraction (SFE) Techniques as an Innovative Green Technologies for the Effective Extraction of the Active Phytopharmaceuticals

The supercritical fluid extraction is a separation method in which separation of chemicals, flavours from the products such as coffee, tea, hops, herbs, and spices which are mixed with supercritical fluid to form a mobile phase. In this process, the mobile phase is subjected to pressures and temperatures near or above the critical point for the purpose of enhancing the mobile phase solvating power. The process begins with CO2 in vapour form. The use of supercritical fluids, especially carbon dioxide, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pre treatment technique. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract. The principle of supercritical fliud extraction is the optimization of the solubility of materials to be extracted (lipids, heavy metals, natural products) in supercritical CO2 and the improvement of the fractionation with respect to a particular lipid species, natural products Supercritical fluid extraction facilitates the detachment of the extract from the supercritical fluid solvent by simple expansion.

Cloud-Point and Bubble-Point Measurement for the Poly(2-butoxyethyl acrylate) + Cosolvent Mixture and 2-Butoxyethyl Acrylate in Supercritical Fluid Solvents

High pressure cloud-point data were reported for poly(2-butoxyethyl acrylate) [P(2-BEA)] in propane (C3H8), propylene (C3H6), butane (C4H10), 1-butene (C4H8), and dimethyl ether (DME) (CH3OCH3), as well as for the P(2-BEA) + 2-butoxyethyl acrylate (2-BEA) (or DME) system in supercritical CO2. Cloud-point pressures for the P(2-BEA) + C3 hydrocarbons curves were ca. 22 MPa higher than those for P(2-BEA) + C4 hydrocarbons, at a constant temperature of ca. 393 K. The cloud-point pressure for the P(2-BEA) + DME system was located between C3 and C4 hydrocarbons at pressures below ca. 20.0 MPa. The P(2-BEA) + CO2 + 0.649 and 0.680 2-BEA phase behavior curves intersect a one phase (fluid) → two phases (liquid + vapor) curve at temperatures of 353.6 K (at 24.5 MPa) and 413.4 K (at 32.3 MPa). The location of the P(2-BEA) + CO2 cloud-point curve shifts to lower temperatures and pressures upon the addition of 2-BEA or DME. Vapor–liquid phase equilibrium data at high pressures were presented for the CO2 + 2-BEA system...

A comparative evaluation between utilizing SAS supercritical fluid technique and solvent evaporation method in preparation of Azithromycin solid dispersions for dissolution rate enhancement

Azithromycin is a poorly water-soluble drug with a lower dissolution rate which resulted in poor bioavailability after oral administration. The aim of this study was to enhance Azithromycin dissolution by a solid dispersion (SD) using solvent evaporation and supercritical fluid based on solvent-anti-solvent technique. Solid dispersions of Azithromycin were prepared with various concentrations of PEG 6000, Sorbitol and Poloxamer 188, SLS (in ternary systems). All samples were studied for the drug solubility. The formulations were also characterized by IR, DSC, XRD and SEM. The solubility and dissolution rate were remarkably improved in case of most SDs prepared with of PEG 6000 (in binary systems, 1:6 ratio) and both surfactants (ternary systems) compared to the related PMs and pure Azithromycin. But the best result was obtained in the dispersion (Azithromycin:PEG 6000:SLS) with a weight ratio of (1:4:2). SAS–SCF processes were signs of less crystallinity of the drug due to the transformation of its crystalline stat into amorphous state. The analysis of dissolution data indicated that enhanced drug dissolution can be achieved where the SDs obtained in the supercritical fluid process was consisted of PEG 6000 and SLS. The dissolution rate and solubility of Azithromycin improved significantly with PEG 6000 and SLS utilizing SAS-supercritical fluid.