Three-liquid-phase salting-out extraction of effective components from waste liquor of processing sea cucumber

A three-liquid-phase (TLP) salting-out extraction system composed of n-hexane/ethanol/sodium carbonate/water was investigated to extract oils, saponins, proteins and polysaccharides simultaneously from waste liquor of processing sea cucumber. The effects of the ratio of ethanol to sodium carbonate, n-hexane concentration and extraction time were investigated. The results showed that 86.7% of oils were distributed in the top n-hexane phase, 82.9% of saponins in the middle ethanol phase, 93.2% of proteins and 92.9% of polysaccharides in the interface between the middle and the bottom salt phase when the system composed of 28% (w/w) n-hexane/11.52% (w/w) ethanol/8.64% (w/w) sodium carbonate was used at 37 °C for 0.5 h. When the system was progressively enlarged from 30 g to 25 kg, the yield of polysaccharides, proteins, oils and saponins was decreased only by 1.0%, 2.8%, 1.0% and 2.6%, respectively. The recycle of salt and solvents in three-liquid-phase system was also studied, and the results showed that the recovery of n-hexane, ethanol and salt were 81.4%, 80.8% and 72.0%, respectively. Recycling materials for the extraction, the yield for proteins and oils decreased by 2.0% and 5.4%, respectively, comparing with the pure system.     

An efficient method for the enrichment of the arachidonic acid methyl ester from Mortierella alpina-derived crude oils

An improved method was developed for enriching arachidonic acid (AA) methyl ester from microbial oil by two-step low-temperature wet fractionation. The effects of solvent, operating temperature, and solvent-to-fatty acid methyl esters (FAMEs) ratio on the enrichment of AA were investigated. The best results were achieved when n-hexane was used as solvent. With operating temperatures in the range ?30 °C to ?80 °C and a FAMEs-to-solvent ratio of 1:5 (v/v), the proportion of AA methyl ester isolated could be increased to 83.76 ± 2.78% with a yield of 52.89%. The total recovery of AA methyl ester would be further increased to 90.84% by recrystallization of the solid phases. The 20C, 22C saturated fatty acids were enriched by n-hexane or petroleum ether at ?30 °C, with concentrations increased 7.5-fold or 7.2-fold compared with their original levels, respectively. In addition, a method that combined alkali and acid catalysis of the transmethylation was the most conducive to the preparation of polyunsaturated fatty acid methyl esters.     

Supercritical CO2 extraction of omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds

Supercritical carbon dioxide (SC-CO₂) was employed to extract omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds and partially defatted cake. For ground seeds, the supercritical extraction was carried out at temperatures of 40, 50 and 60 °C and pressures of 300 and 400 bar, and for the cold pressed partially defatted cake, the extraction was carried out with 300 bar at 40 °C and with 400 bar at 60 °C. The global extraction yields (X₀), oil solubility, fatty acid composition of the oil and tocopherol content were determined. The seed samples used in this work contained 54.3% oil, of which 50.5% was linoleinc acid (ω-3). The maximum extraction recovery for the seeds as 92% at 400 bar and 60 °C, but on one occasion a recovery of 99.1% oil was obtained when cold pressed extraction was employed, followed by supercritical extraction at 400 bar and 60 °C. A high tocopherol content of about 2–3 g/kg of oil was obtained.     

Extraction of rotundifuran and casticin from chaste tree fruits by near critical liquid carbon dioxide

In this study we investigated the use of near critical liquid CO₂ for the extraction of chaste tree ripe fruits (Vitex agnus-castus L.). Two procedures utilizing near critical liquid CO₂ were tested: (1) the extraction of plant material via continuous solvent recycling and (2) the extraction by a Soxhlet-type process via periodic solvent recycling. The results were compared with data obtained from the traditional Soxhlet extraction process using three different solvents, namely n-hexane, dichloromethane, and methanol. Extractions with liquid CO₂, recycled in continuous mode, of chaste tree fruits in three sizes: (1) <0.3 mm, (2) 0.3–0.8 mm, and (3) 3–3.2 mm resulted in maximum yields of 4.9%, 4.1% and 2.8%, respectively. Extraction times of 0.17–25 h were used. Extraction by continuous recycling of liquid CO₂ is more efficient than Soxhlet-type periodic recycling of liquid CO₂, resulting in up to three times higher yield for the same solvent-to-feed ratio. Comparison of HPLC data for extracts obtained by liquid CO₂, n-hexane, dichloromethane and methanol showed that the diterpene rotundifuran is best extracted by liquid CO₂ (3.010 g/kg drug), and the flavonoid casticin is best extracted by n-hexane (1.067 g/kg drug).     

Lipase Catalyzed Synthesis of Medium-chain Biodiesel from Cinnamonum camphora Seed Oil

The non-edible camphor tree seed oil was extracted and catalyzed by immobilized lipase for biodiesel production. The oil yield from camphor tree seeds reached 35.2% of seed weight by twice microwave-assisted extractions. Gas chromatography showed that free fatty acid content in camphor tree seed oil was 1.88%, and the main fatty acids were capric acid (53.4%) and lauric acid (38.7%). With immobilized lipase Candida sp. 99–125 as catalyst, several important factors for reaction conditions were examined through orthogonal experiments. The optimum conditions were obtained: water content and enzyme loading were both 15% with a molar ratio of 1:3.5 (oil/ethanol), and the process of alcoholysis was in nine steps at 40 °C for 24 h, with agitation at 170 r·min^− 1. As a result, the medium-chain biodiesel yield was 93.5%. The immobilized lipase was stable when it was used repeatedly for 210 h.     

Exploiting microalgae as a source of essential fatty acids by supercritical fluid extraction of lipids: Comparison between Scenedesmus obliquus,Chlorella protothecoides and Nannochloropsis salina

Supercritical CO₂ extraction from microalgae is applied with the aim of obtaining an oil rich in α-linolenic (ALA) essential fatty acid and with a low ω6:ω3 ratio. The maximum extraction yield is obtained at 60 °C and 30 MPa with 0.4 kg/h of CO₂ and 5% of co-solvent (ethanol). When the effect of pressure, temperature and density on the supercritical extraction yield and solubility are studied, the thermodynamic cross-over is found at a pressure close to 30 MPa, while the extraction cross-over occurs at around 25 MPa. The experimental solubility data are correlated by literature empirical models. Mathematical models developed by Sovová are applied to describe the experimental extraction curves. Soxhlet extraction of lipids is also carried out, obtaining a similar fatty acids profile but proving to be less selective than SCCO₂ method. Among the three species of microalgae examined, results show that Scenedesmus obliquus oil is richer in ω-3 fatty acids and ALA than Chlorella protothecoides and Nannochloropsis salina lipids. The effect of the extraction parameters on ALA content and the fatty acid profile is also analysed, concluding that the ω-3 percentage is favoured by lower temperatures, lower pressures and shorter extraction times.     

Enrichment of Nigella damascena extract with volatile compounds using supercritical fluid extraction

β-Elemene, germacrene A and damascenine were extracted from lady-in-a-mist (Nigella damascena L.) seeds with supercritical carbon dioxide at 10–30 MPa and 40–60 °C. The influence of supercritical fluid extraction (SFE) conditions on the yield and concentration of volatiles in the extract and the extraction kinetics were studied. The extraction yields and the apparent solubility of volatile compounds increased with increasing density of CO₂. The highest total yield was obtained at 30 MPa and 40 °C but the selectivity for volatiles was low under these conditions. With respect to both yield of volatiles and their concentration in extract, the best results were at 12 MPa and 40 °C, either with one separator or with additional separator maintained at 5 MPa and 25 °C. The yields of β-elemene, germacrene A and damascenine reached 0.72, 3.31 and 3.65 mg g⁻¹ and their concentration in the extract was 2.62, 12.04 and 13.28 wt.%, respectively. Though the yields of germacrene A and damascenine were by about 20% higher using Soxhlet extraction with hexane than using SFE, their concentration in the extract where fatty oil prevailed was only 1.19 and 1.20 wt.%, respectively. Under the conditions of hydrodistillation, partial conversion of germacrene A to β-elemene occurred and its yield was higher than using the other methods but the composition of volatiles in the SFE extracts better corresponds to the original raw material.     

Optimization of the supercritical fluid coextraction of oil and diterpenes from spent coffee grounds using experimental design and response surface methodology

The reported work aimed at the optimization of operating conditions of the supercritical fluid extraction (SFE) of spent coffee grounds (SCG) using pure or modified CO₂, with particular emphasis on oil enrichment with diterpenes like kahweol, cafestol and 16-O-methylcafestol. The analysis comprised the application of Box–Behnken design of experiments and response surface methodology, and involved three operating variables: pressure (140–190 bar), temperature (40–70 °C) and cosolvent (ethanol) addition (0–5 wt.%). The best conditions to maximize total extraction yield are 190 bar/55 °C/5 wt.% EtOH, leading to 11.97% (g_oil/100 g_SCG). In terms of the concentration of diterpenic compounds in the supercritical extracts, the best operating conditions are 140 bar/40 °C/0 wt.% EtOH, providing 102.90 mg g⁻¹_oil. The measurement of extraction curves near optimized conditions (140 bar/55 °C/0 wt.% EtOH and 190 bar/55 °C/0 wt.% EtOH) confirmed the trends of the statistical analysis and revealed that SFE enhances diterpenes concentration by 212–410% at the expenses of reducing the extraction yield between 39% and 79% in comparison to n-hexane extraction.     

Optimization of supercritical fluid extraction of phytosterol from roselle seeds with a central composite design model

Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon dioxide extraction modified with ethanol was investigated at pressures of 200–400 bar, temperatures from 40 to 80 °C and at supercritical fluid flow rates from 10 to 20 ml/min. It was found that an entrainer such as ethanol could enhance the solubility and extraction yield of roselle seed oil from the seed matrix, compared to values obtained using supercritical CO₂. After a typical run (holding period of 30 min, continuous flow extraction of 3 h), the results indicate that the oil recovery was optimal with a recovery of 108.74% and a phytosterol composition of 7262.80 mg kg^?1 at relatively low temperature of 40 °C, a high pressure of 400 bar and at a high supercritical fluid flow rate of 20 ml/min in the presence of 2 ml/min EtOH as entrainer. The solubility of roselle seed oil increased with temperature at the operating pressures of 200, 300 and 400 bar. Supercritical fluid extraction involved a short extraction time and the minimal usage of small amounts of entrainer in the CO₂.     

Extraction and solubility evaluation of functional seed oil in supercritical carbon dioxide

Hemp (Cannabis sativa L.) seed oil is valued for its nutritional properties and for the health benefits associated with it. Its greatest feature is that the ratio of linoleic acid and linolenic acid is the desirable value of 3:1. In this research, supercritical carbon dioxide was applied to extraction of functional oil from hemp seed. In order to determine the effect of temperature and pressure on the yield of extracted components, the oil was extracted from hemp seed at temperatures between 40 and 80 °C, pressures of 20–40 MPa and a CO₂ flow rate of 3 mL/min. The solubility of hemp seed oil in SCCO₂ determined experimentally was fitted to the Chrastil equation to determine the model parameters. The solubility calculated by Chrastil equation was compared with the experimental data. Finally, the fatty acid profile of the oil was evaluated by gas chromatography-flame ionization detection (GC-FID). There are no significant differences in the compositions of five abundant fatty acid components of the oil obtained at different sampling times with SCCO₂ extraction and other extraction methods.     

Application of response surface methodology for the optimization of supercritical carbon dioxide extraction and ultrasound-assisted extraction of Capparis spinosa seed oil

Caper (Capparis spinosa) seed oil growing wild in Iran was extracted using supercritical CO₂ and ultrasound-assisted extraction methods. The experimental parameters of SFE and UAE were optimized using a rotatable central composite design. The highest yield for SFE was obtained at a pressure of 355 bar, temperature of 65 °C, modifier volume of 140 μL, static and dynamic extraction time of 10 and 35 min, respectively, and for UAE was gained at solvent volume of 23 mL, sonication time of 45 min and temperature of 40 °C. This resulted in a maximum oil recovery of 25.1% and 27.9% for SFE and UAE, respectively. The extracts with higher yield from both methods were subjected to transesterification and GC–MS analysis. SFE and UAE processes selectively extracted the fatty oils with high percentage of omega-6 and omega-9-fatty acids. The major components of the extracted oils from both methods were linoleic, oleic, its positional isomer cis-vaccenic and Palmitic acid.     

Allelopathic properties of the fractions obtained from sunflower leaves using supercritical carbon dioxide: The effect of co-solvent addition

The work described here is a continuation of a previous study centered on the extraction, using supercritical carbon dioxide, of bioactive substances from sunflower leaves of the Helianthus annuus L. variety Arianna. In this study the addition of 9% of ethanol as co-solvent was analyzed. The extraction was carried out (P = 100/400 bar, T = 35/55 °C, ethanol = 9%) in order to analyze the influence of pressure, temperature and sample pre-treatment on the extraction yield and bioactivity of the extracts. The addition of 9% of ethanol to the supercritical solvent enhanced both the extraction yield and the biological activity of the extracts. The best conditions were a pressure of 400 bar and a temperature of 55 °C. In an effort to improve the bioactivity of the extract, a cascade fractionation of the extracts was carried out and this gave different results in terms of biological activities and extraction yields. The phytochemical compositions of the extracts were analyzed by thin layer chromatography. The fractionation that gave the best results was carried out at 90 bar and 40 °C in the first separator. Finally, the effect of extracts on the growth of seeds from different plants was analyzed.     

Extraction of oil and β-sitosterol from peach (Prunus persica) seeds using supercritical carbon dioxide

Oil was extracted from the peach (Prunus persica) seeds by supercritical carbon dioxide. Principal phytosterols (stigmasterol, campesterol and β-sitosterol) that have been known to have cholesterol lowering properties were investigated in the extracted oil. Based on gas chromatography–mass spectrometry (GC–MS) analysis, β-sitosterol was identified in the peach seed oil. The effects of temperature, pressure, flow rate of supercritical CO₂, mean particle size of the seeds and extraction time on the amounts of extracted oil and β-sitosterol were investigated. Supercritical fluid extractions were performed in a range of 35–55 °C, 160–240 bar, 4–8 ml CO₂/min, 0.3–1.7 mm and 1–4 h for mentioned parameters. The results indicated that the amounts of oil and β-sitosterol extracted from the peach seeds were optimal with values of 35.3 g/100 g seed and 1220 mg/kg seed respectively at 40 °C, 200 bar, 7 ml/min, 0.3 mm and 3 h.     

Influence of pretreatment on supercritical CO2 extraction from Nannochloropsis oculata

This work demonstrates that supercritical carbon dioxide extraction is efficient for the complete recovery of neutral lipids from microalgae with a water content up to 20 wt%, allowing thus a further full characterization of this oil. This is a first useful step in the framework of lipid production from microalgae either for nutraceutical, food or for energy applications. This study is particularly focused on the influence of the pretreatments upon extraction kinetics and yields. This study proposes a complete study at laboratory scale (10 g per batch of dry biomass) of the influence of pretreatments (type of drying and grinding) and of water content on the extraction kinetics and yields as well as on the oil composition in terms of lipidic classes and profiles. Two drying pretreatments (drying under air flow and freeze-drying) applied on Nannochloropsis oculata were studied. Extraction experiments were carried out at 40 MPa, 333 K, with a carbon dioxide flow rate of 0.5 kg h⁻¹ and for different granulometries. Results showed that drying under air flow at 308 K is the most adequate pretreatment leading to the most rapid kinetics. Whatever the pretreatment used, the extracted oil contains more than 90 wt% of triglycerides and does not contain phospholipids. As expected, the smaller the particle size, the faster the extraction kinetics. Finally, an increase in the biomass water content up to 20 wt% increases the global extraction kinetics (extraction of both water and oil) but appears to have no influence on oil extraction yields. Moreover, the extraction of neutral lipids happens to be complete for a CO₂/charge mass ratio ranging from 30 to 130 depending on the operating conditions and on the characteristics of the treated biomass. Finally, pilot scale experiments were performed with batches up to 15 kg in order to evaluate the influence of pressure and particle size on the extraction kinetics and yields. Extracts obtained at 333 K with operating pressures of 50 MPa and 85 MPa have similar compositions and do not contain phospholipids.     

Comparison of essential oils compositions of Nepeta persica obtained by supercritical carbon dioxide extraction and steam distillation methods

Essential oil of Nepeta persica cultivated in Iran was obtained by steam distillation and supercritical (carbon dioxide) extraction methods. The oils were analysed by capillary gas chromatography using flame ionization and mass spectrometric detections. The compounds were identified according to their retention indices and mass spectra (EI, 70 eV). The effects of different parameters such as pressure, temperature, modifier volume and extraction times (dynamic and static) on the supercritical fluid extraction (SFE) of N. persica oil were investigated. The results showed that under the pressure of 20.3 MPa, temperature of 45 °C, methanol of 1.5% v/v), dynamic extraction time of 50 min and static extraction time of 25 min extraction was more selective for the 4αβ,7α,7aα-nepetalactone. Twelve compounds were identified in the steam-distilled oil. The major components of N. persica were 4αβ,7α,7aα-nepetalactone (26.5%), cis-β-farnesene (4.4%) and 3,4α-dihydro-4aα,7α,7aα-nepetalactone (3.5%). However, by using supercritical carbon dioxide under optimum conditions, only two components have more than 90.0% of the oil. The extraction yield based on steam distillation was 0.08% (v/w). On the other hand, using SFE extraction yield in the range of 0.22–8.90% (w/w) were obtained at different conditions. The results show that, in Iranian N. persica oil, 4αβ,7α,7aα-nepetalactone is a major component.     

Aqueous enzymatic extraction of peanut oil and protein hydrolysates

The aqueous enzymatic process of simultaneously preparing oil and protein hydrolysates from peanut was investigated. The optimum parameters for hydrolysis using Alcalase 2.4L were established by the single-factor and orthogonal test. The optimal processing conditions were as follows: hydrolysis temperature 60 °C, pH 9.5, ratio of material to water 1:5 (w/w), alkaline extraction time 90 min, enzyme amount 1.5% (w/w) and hydrolysis time 5 h. Under these conditions, the free oil and protein hydrolysates yields were 79.32% and 71.38% respectively. In order to improve these yields, As1398 was chosen to hydrolyze the residue and emulsion. The total free oil and protein hydrolysates yields were increased to 91.98% and 88.21% respectively.     

Enzymatic production of biodiesel from Pistacia chinensis bge seed oil using immobilized lipase

Biodiesel fuel from renewable non-edible woody plant oils has recently attracted more attention due to its environmental benefits and the reduced costs of raw materials. This study investigated the enzymatic transesterification of Pistacia chinensis bge seed oil (PCO) with methanol. The recombinant Rhizopus oryzae lipases (ROL) immobilized on macroporous resin and anion exchange resin, named as MI-ROL and AI-ROL, respectively, were used as biocatalysts. The transesterification reaction catalyzed by the immobilized lipase was investigated in a solvent-free system. The highest biodiesel yields of 92% and 94% were achieved under the optimum conditions (enzyme dosage 25 IU_AI-ROL/g PCO or 7 IU_MI-ROL/g PCO, methanol to oil molar ratio 5:1, water content 20% by weight of oil, temperature 37 °C, and reaction time 60 h). There was no obvious loss in the yield of biodiesel after being consecutively used for five cycles in the transesterification reactions using AI-ROL, while the yield of biodiesel remained above 60% after the MI-ROL was repeatedly used for four cycles.     

Supercritical CO2 oilseed extraction in multi-vessel plants. 2. Effect of number and geometry of extractors on production cost

The objective of this work was to study production costs for the supercritical CO₂ extraction of a pre-pressed oilseed (packed bed with 2-mm particles) in a 2-m³ industrial multi-vessel plant operating at 40 °C and 30 MPa, using a fully predictive mass transfer model to simulate the process. We modified the inner diameter (47.3 ≤ D ≤ 65.6 cm) and number (n = 2, 3, or 4) of extraction vessels, and the mass flow rate of CO₂ (Q = 3000 or 6000 kg/h), thus changing the aspect ratio of the extraction vessels (3 ≤ L/D ≤ 8), and superficial velocity (2.71 ≤ U ≤ 10.8 mm/s) and specific mass flow rate (6 ≤ q ≤ 24 kg/h per kg substrate) of CO₂. Production cost decreased when increasing the mass flow rate of CO₂ or the number of extraction vessels (or when increasing q). Production cost did not depend on the geometry of extraction vessel for a constant specific mass flow rate of CO₂, but it decreased with a decreasing of the L/D ratio of the vessel for a constant superficial velocity of CO₂. For any given plant, the contribution of fixed cost items (capital, labor) to the production cost increased with extraction time, unlike that of variable cost items (substrate, CO₂, energy), which decreased. Thus, there was an optimal extraction time that minimized production cost for each plant. This work proposes an expression for capital cost of an industrial multi-vessel plant as a function of the mass flow rate of CO₂ (which defines the cost of the solvent cycle of the plant), and the volume of the extraction vessels (which together with number of extraction vessels define the cost of extraction section of the plant), with a scaling factor of 0.48 for both items. Under optimal conditions, capital cost represented 30–40% of the production cost, but uncertainties in capital cost estimates (about ±50% using the proposed expression) may largely affect these estimates. The lowest production cost estimated in this work was USD 7.8/kg oil for the extraction of prepressed oilseed in a four-vessel plant using 6000 kg/h of CO₂. The mass flow rate of CO₂ and number of extraction vessels also affected annual productivity that was about 360 ton oil for the same plant operating 7200 h per year. Oil yields were above 90% for both three- and four-vessel plants.     

Dynamic removal of n-hexane from water using nanocomposite membranes: Serial coating of para-aminobenzoate alumoxane,boehmite-epoxide and chitosan on Kevlar fabrics

Nanocomposite membranes were fabricated by dip-coating technique. Para-aminobenzoate alumoxane, boehmite–epoxide and chitosan were consecutively coated on the Kevlar fabric surface. The membranes were utilized for removing n-hexane from water using a gravity-driven dead-end filtration setup. UV–vis, FTIR and SEM analyses were performed for characterization. Water affinity analyses revealed highly hydrophilic nature of the modified membranes. Effect of pH was examined with the pH 2 providing the best condition for oil–water separation. Maximum flux and rejection were obtained as 1128 L m⁻² h⁻¹) and 94%, respectively. Deposited oil layer was effectively removed from the membrane surface using hot citric acid solution.     

Production of concentrated natural beta-carotene from buriti (Mauritia vinifera) oil by enzymatic hydrolysis

The present work aimed at the extraction and concentration of β-carotene from crude and refined buriti oils using enzymatic hydrolysis as a process strategy. The performance of two commercial lipolytic preparations (Lipozyme TL IM and CALB L), as well as lipases from Yarrowia lipolytica, was evaluated. The parameters considered in the hydrolysis process were: temperature, enzyme loading and ratio buriti oil/water. Based on a previously conducted statistical design, the experimental conditions were set in order to maximize the free fatty acids (FFA) content in the oil, and simultaneously, minimize the loss of carotenoids. Lipozyme TL IM showed to be the most appropriate enzyme source for the hydrolysis of both oils. The optimized conditions determined for the crude buriti oil processing were 31 °C, 0.0047 g lipase mL^?1 (0.47 g lipase per 100 mL reactional mixture) and 2.33 (ratio oil/water), while for the refined oil, 45 °C, 0.0066 g lipase mL^?1 and 1.80 were the best conditions. At the optimized conditions, the maxima FFA release were 73.0% and 74.8% and the total carotenoids contents were 1578 and 793 mg kg^?1, respectively for the crude and the refined buriti oils, after 4 h of reaction agitated at 300 rpm. Following hydrolysis, oils were deacidified by winterization or phases partition with ethanol.