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•Continuous supercritical extraction with toluene was used to extract oligomers from pyrene pitch.•90% pure mixture of dimers and trimers had a char yield of just under 50%•Stripping ...unreacted monomer from the pitch produced a low-melting pitch with a char yield of 65%.•Synergy between individual oligomers results in higher-than-expected char yields.
Continuous supercritical extraction (SCE) was investigated for its ability to control the oligomeric composition of a pyrene pitch generated by the catalytic polymerization of pyrene in the presence of AlCl3. Key objectives of this work were the nearly complete removal of the starting monomer, generation of a well-defined pitch with a high char yield, and isolation of a fraction consisting exclusively of intermediate-sized oligomers. Following the design and construction of an SCE unit for processing up to 500 g/h of feed pyrene pitch with supercritical toluene (Tc = 319 °C, Pc = 41.1 bar), a 2-column setup was used to isolate ∼350 g of a fraction consisting of greater than 90 % isotropic dimer plus mesogenic trimer combined. Although the char yield of this oligomeric mixture was only moderate (i.e., 47.1 %), it still significantly exceeded the weighted average char yield (i.e., 30 %) of the individual monomers present, suggesting a synergistic interplay between the different species during charring. With the above results indicating that pyrene oligomers larger than trimer (i.e., X-mers) are needed to attain higher char yields, the focus of our next continuous SCE run was simply on removing as much unreacted monomer as possible, to the exclusion of all other oligomers. Using a one-column SCE setup, a ∼350 g fraction containing almost 90 % dimer and higher oligomers was isolated, and a respectable char yield of 65.2 % was obtained with this “monomer-depleted” pitch. Furthermore, the softening point was a relatively low 185 °C, quite respectable in terms of processability. In summary, these initial results indicate the potential of continuous SCE as a tool for controlling the properties of oligomeric pyrene pitches for selected applications.
An interest in the development of extraction techniques of biomolecules from various natural sources has increased in recent years due to their potential applications particularly for food and ...nutraceutical purposes. The presence of polysaccharides such as hemicelluloses, starch, pectin inside the cell wall, reduces the extraction efficiency of conventional extraction techniques. Conventional techniques also suffer from low extraction yields, time inefficiency and inferior extract quality due to traces of organic solvents present in them. Hence, there is a need of the green and novel extraction methods to recover biomolecules. The present review provides a holistic insight to various aspects related to enzyme aided extraction. Applications of enzymes in the recovery of various biomolecules such as polyphenols, oils, polysaccharides, flavours and colorants have been highlighted. Additionally, the employment of hyphenated extraction technologies can overcome some of the major drawbacks of enzyme based extraction such as longer extraction time and immoderate use of solvents. This review also includes hyphenated intensification techniques by coupling conventional methods with ultrasound, microwave, high pressure and supercritical carbon dioxide. The last section gives an insight on application of enzyme immobilization as a strategy for large scale extraction. Immobilization of enzymes on magnetic nanoparticles can be employed to enhance the operational performance of the system by multiple use of expensive enzymes making them industrially and economically feasible.
Extraction of various biomolecules by using enzyme assisted extraction. Display omitted
•Application of enzyme assisted extraction in the recovery of various biomolecules.•Enzymes disrupt the complex cell wall structure to release the active constituents.•Novel extraction methods coupled with enzyme assisted extraction is reviewed.•Enzyme immobilization as a strategy for large scale application is explored.•Magnetic nanoparticles are considered as potential carriers for enzyme immobilization.
•A new methodology was developed for the recovery of extract rich in antioxidant polysaccharide.•Box-Behnken design allowed the prediction of optimal conditions in H2O + CO2-SFE.•Temperature and ...pressure influence the obtainment of polysaccharide extract with H2O + CO2-SFE.•Anomeric bonds, identified in the FTIR and NMR spectrum, indicate that the extract is rich in polysaccharides.•The extract obtained with H2O + CO2-SFE showed high antioxidant activity in vitro and in a cell model.
Pleurotus ostreatus is an edible mushroom with pharmacological potential, due to its metabolites, mainly polysaccharides. On here, the development of a new methodology for the recovery of extract rich in antioxidant polysaccharide was reported. The extracts were characterized, evaluated for antioxidant activity in vitro and in cell models and cytotoxicity. The best defined extraction condition was 25 MPa, 433.15 K, and 20% H2O, with 30.69% of the total yield and 0.921 mg of CHO3. The anomeric bonds, identified in the FTIR and NMR spectrum, indicate that the extracts are a mixture of heteropolysaccharides, β-glucans, α-glucans, and oligosaccharides. The best extraction condition has 80.83% of antioxidant activity, without cytotoxic effect in vitro. In addition to antioxidant activity in cell model, increasing protection against oxidative damage induced by H2O2. Finally, H2O + CO2-SFE technology can be used to obtain extracts rich in antioxidant polysaccharides with pharmacological and food potential.
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•First report of supercritical CO2 extraction (SFE) of Lippia graveolens leaves.•The best scCO2 conditions were 35.0 MPa and 60 °C.•Carvacrol was the majority compound in all the ...experiments.•Biological activity of carvacrol from oregano could promote future research.•A three extraction stages model fit very well the experimental yields.
In this study, leave extracts of Lippia graveolens were obtained using supercritical CO2. The objective was to evaluate the effect of temperature and pressure on the extraction yield and kinetics. Supercritical fluid extractions were performed at three pressures (13, 15 and 35 MPa) and two temperatures (40 and 60 °C). Sovová’s model for supercritical fluid extraction was fitted to describe the kinetic extraction curves and analyze the results. The extracts were analyzed by GC–MS, where Carvacrol was the majority compound in all the experiments. A maximum yield of 2.6% on a dry weight basis was obtained at 35 MPa and 60 °C. The extraction yield increased with temperature and pressure, in all the analyzed samples.
This paper provides insights on the properties of bio-oil obtained from various feedstock and several available mechanisms for bio-oil upgrading. A comprehensive detail on the catalytic cracking, ...hydrodeoxygenation, esterification, supercritical extraction and steam reforming processes are reviewed. Each upgrading technique has both advantages and disadvantages. The hydrodeoxygenation which has the major breakthrough in the bio-oil upgrading, even though there is no specific inference on the process chemistry in addition to various unfavorable conditions, this process holds good in reducing the oxygen contents of raw bio-oil. Various types of catalysts, their limitations along with the advantages, the use of novel catalysts and catalyst deactivation due to char formation at specified conditions among different upgrading techniques are presented. From this review, it was found that there is no specific catalyst for the specific compound upgrading. There is no specific reaction pathways defined for the processing of bio-oil. All the reviews and researches so far are constrained to the individual compounds of bio oil rather than as a whole. Some key points which are to be addressed for established process of bio-oil upgrading may include finding multifunctional catalysts which can improve the bio-oil properties suitable to blend with existing transportation fossil fuels or to directly use as transportation fuels, studies at pilot plant level, establishment of design concepts as in existing petroleum refineries, and numerical approaches to find various possible reaction pathways leading to upgraded bio-oil.
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In this review, recent advances in greener technology for extracting natural bioactive components from plant origin sources are discussed. Bioactive compounds of plant origin have been defined as ...natural chemical compounds present in small amounts in plants. Researchers have shown interest in extracting bioactive compounds because of their human health benefits and characteristics of being eco-friendly and generally recognized as safe. Various new extraction methods and conventional extraction methods have been developed, however, until now, no unique approach has been presented as a benchmark for extracting natural bioactive compounds from plants. The selectivity and productivity of traditional and modern extraction techniques generally depend on selecting the critical input parameters, knowing the nature of plant-based samples, the structure of bioactive compounds, and good scientific skills. This work aims to discuss the recent advances in supercritical fluid extraction techniques, especially supercritical carbon dioxide, along with the fundamental principles for extracting bioactive compounds from natural plant materials such as herbs, spices, aromatic and medicinal plants.
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•Using dissipative particle dynamics, investigate how the alkanes in crude oil are extracted.•The effect of extraction has on the miscible and immiscible displacement of carbon ...dioxide and crude oil.•The images of the extraction are exhibited at the molecular level.
Understanding the phase behavior of a CO2-oil–water surfactant system is critical for carbon dioxide flooding engineering. Using dissipative particle dynamics, we investigate how the alkanes in crude oil are extracted after the injection of supercritical carbon dioxide into the formation, and what effect this extraction has on the miscible and immiscible displacement of carbon dioxide and crude oil. The images of the extraction are exhibited at the molecular level, and the effects of temperature and pressure on the extraction are investigated. The phase distribution of carbon dioxide, oil, and water under immiscible phase is simulated using actual reservoir fluid data based on a comprehensive understanding of extraction. Oil tends to be spread at the interface of carbon dioxide and water when it is immiscible. The miscible pictures were generated under conditions of reduced CO2-oil–water miscible pressure by adding surfactants to the CO2-oil–water system, and the fluid distribution characteristics under immiscible and miscible phases were examined. dissipative particle dynamics (DPD) simulation demonstrates that when the molar proportion of carbon dioxide is less than 0.4, the solid phase surface can always create a water film of varied thickness, regardless of whether the surface charge of the solid phase is positive or negative. As the molar fraction of carbon dioxide increases, the water film’s thickness decreases.
Essential oil of rosemary was obtained by supercritical CO2-extraction (SCE), hydrodistillation (HYDRO), and steam distillation (SD). Quantity of oil, antioxidant activity, and chemical composition ...(gas chromatography-mass spectrometry, GC-MS) of the essential oils were evaluated. For SCE, oil was obtained at two temperatures (40 and 50 °C) and two pressures (10.34 and 17.24 MPa) using a rosemary particle size of 600 ± 50 μm. The yield was between 1.41 and 2.53 g essential oil (EO) 100 g−1 of dry rosemary (% w/w). The antioxidant activity values were in the range 29.67–37.55 mg equivalent of Trolox (ET) g−1 of EO or 22.66–30.81 mg ascorbic acid (AA) g−1 of EO. Yields of essential oil were between 0.35 and 2.35%. The antioxidant activity was found in the range 1.73–2.60 mg ET g−1 of EO or 1.50–2.20 mg AA g−1 of EO. Camphor, eucalyptol, β-caryophyllene, and borneol acetate were the main chemicals detected by GC-MS in EO.
•Essential oil of rosemary obtained by supercritical and steam distillation.•The yield of oil was between 1.41 and 2.53 g essential oil/100 g d.s. (% w/w).•Antioxidant activity was in the range 29.67–37.55 mg equivalent of Trolox/g oil.•Essential oil extracted by hydrodistillation yielded between 0.35 and 2.35%.•Camphor, eucalyptol, and β-caryophyllene were the main chemicals in essential oil.
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•Supercritical oil extracts from black sesame seeds were obtained.•Supercritical oil extracts have higher antioxidant activity than Soxhlet oil extract.•Supercritical extracts were ...efficient in stabilizing purified sunflower oil.•Protein concentrates were obtained from the residues of oil extraction.•No differences were found in techno-functional properties of protein concentrates.
Extraction with supercritical CO2 as a solvent was evaluated in order to obtain functional additives from black sesame seeds, and compared to Soxhlet method. From the residues of oil extraction, protein concentrates were obtained by isoelectric precipitation.
To evaluate the antioxidant activity extracts obtained were added to purified sunflower oil. Induction period (IP) of the oxidation process was determined at 100 °C. Also, fatty acids composition and the content of total phenols and tocopherols were determined. The use of ethanol as co-solvent in the supercritical extraction allows obtaining an increase in the yield, the content of total phenols, and the IP.
In the protein concentrates obtained protein content, protein solubility as a function of pH, thermal behavior and emulsifying properties were evaluated. No large differences were found in protein content, protein solubility and emulsion destabilization kinetics of the concentrates, indicating that the oil extraction method did not affect the protein performance.
Isolation of volatile and fixed oils from nutmeg have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at pressures of 90 and 250 bar ...and temperature of 40 °C. The extraction step performed at 90 bar produced a volatile fraction mainly formed by myristicin (32.8%), sabinene (16.1%), α‐pinene (9.8%), β‐pinene (9.4%), β‐phellandrene (4.9%), safrole (4.1%) and terpinen‐4‐ol (3.6%). The oil yield relative to this step of the process was 1.4% by weight of the charge. The last extraction step at 250 bar produced a butter‐like material (nutmeg butter). The yield of this step was 14.4% by weight. The most represented fatty acids of fixed oil from nutmeg were 14:0 (79.2%), 18:1 n‐9 (7.4%) and 16:0 (6.1%), and in particular the unsaturated fatty acids 18:1 n‐9 averaged 32.96 μg/mg of oil. The level of myristicin in the nutmeg essential and fixed oils was also directly quantified by reversed HPLC‐DAD. Moreover, the essential oil obtained from nutmeg, as well as myristicin, showed a significant
in vitro
inhibitory effect on the growth of a colon cancer cell line (undifferentiated Caco‐2 cells).
Practical Application:
In this study, the chemical characterization and the anticancer activity of nutmeg oils obtained by supercritical extraction with carbon dioxide were investigated. This is important for their potential application in food and pharmaceutical industries.
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