Pressurized Fluid Extraction Research Articles

Pressurized Fluid Extraction.

Pressurized Fluid Extraction.

Pressurized-fluid extraction of cafestol and kahweol diterpenes from green coffee

Abstract Cafestol and kahweol were extracted from green coffee beans ( C. arabica ) using a pressurized-fluid extraction (PFE) system. The effects of extracting solvent (i.e. water, ethanol and methanol), flow rate (0.5, 1.0, 2.0 and 3.0 mL · min − 1 ), extraction temperature (60, 80 and 100 °C) and time on extraction efficiency of coffee diterpenes were investigated. Quantification of diterpenes extracts was achieved by HPLC-UV method. The solvent flow rate was clearly the most significant process parameter. Diterpenes recovery resulted also influenced by temperature, except for the lowest flow rate, indicating solubility and mass transfer constraints. Kinetic degradation was also examined suggesting a thermolability of the diterpenes at 100 °C. The optimum extraction conditions were 100 °C and 3.0 mL · min − 1 using methanol. Under these conditions, PFE showed a remarkably higher efficiency compared with conventional extraction techniques. Industrial relevance Coffee is the world's most traded food commodity. Coffee-specific diterpenes (i.e. cafestol and kahweol) are high-value bioactive compounds, naturally occurring in the coffee lipid fraction. However, they are not easy to separate and likely to be unstable when isolated. High-pressure extraction, namely pressurized fluid extraction (PFE), appears as an attractive option as it reduces extraction time, thus avoiding degradation of thermolabile compounds, while requiring smaller quantities of solvent than traditional extraction methods (e.g. Soxhlet). PFE offers the possibility to operate with a wide range of liquid solvents well above their boiling point, but very little information can be found on the effect of operational conditions to efficiently recover coffee diterpenes. Such knowledge provides a basis for the rational design of PFE processes and, may be useful to allow industrial scale-up interpretation for coffee diterpenes extraction.

A Procedure for Measuring Microplastics using Pressurized Fluid Extraction.

A method based on pressurized fluid extraction (PFE) was developed for measuring microplastics in environmental samples. This method can address some limitations of the current microplastic methods and provide laboratories with a simple analytical method for quantifying common microplastics in a range of environmental samples. The method was initially developed by recovering 101% to 111% of spiked plastics on glass beads and was then applied to a composted municipal waste sample with spike recoveries ranging from 85% to 94%. The results from municipal waste samples and soil samples collected from an industrial area demonstrated that the method is a promising alternative for determining the concentration and identity of microplastics in environmental samples.

Recovery of antioxidant and antiproliferative compounds from watercress using pressurized fluid extraction

The potential of pressurized fluid technology to isolate bioactive antioxidant and antiproliferative compounds from watercress was studied.

Determination of selected polycyclic aromatic compounds in particulate matter: a validation study of an agitation extraction method for samples with low mass loadings using reduced volumes

A simple analytical method using low volumes of solvent for determining selected PAHs and NPAHs in PM samples is presented. The proposed extraction method was compared with pressurized fluid (PFE) and microwave (MC) extraction techniques and intermediate precision associated to analytical measurements were estimated. Extraction by agitation with 8 mL of dichloromethane yielded recoveries above 80% compared to those obtained from PFE extraction. Regarding intermediate precision results, values between 10-20% were reached showing increases of dispersion for compounds with high volatility and low levels of concentration. Within the framework of the INTA/CIEMAT research agreement for the PM characterization in gas turbine exhaust, the method was applied for analysis of aluminum foil substrates and quartz filters with mass loading ranged from 0.02 to 2 mg per sample.

Determination of antioxidants in polyolefins by pressurized liquid extraction prior to high performance liquid chromatography

The effect that a high amount of mineral filler might have on the extraction process of antioxidants from polyethylene and polypropylene was investigated. Extraction of Irganox 1010, Irganox 1076 and Irgafos 168, along with its oxidation product 2,4-di-tert-butylphenol, from freeze ground polyethylene–based (PE–based) and polypropylene–based (PP–based) mineral concentrates of 85 w/w calcium carbonate (CaCO3) and 75 w/w talc was carried out by pressurized fluid extraction (PLE) prior to high performance liquid chromatography (HPLC). Results indicate that 85 w/w CaCO3 did not affect the extraction process from PE or PP. For talc concentrates, additive recovery from PE and PP was considerably lower. The relation of recovery yield and mixing time was investigated for the talc concentrates and it was concluded that the presence of talc seemed to accelerate the rate of antioxidant consumption during sample processing, thus, less antioxidant was left to be extracted from the polyolefin; rather than talc has limited the extraction process. The method developed in this work has been applied to determine these compounds in several commercial samples.

Pressurised fluid extraction of polycyclic aromatic hydrocarbons and their polar oxidation products from atmospheric particles

An effective method utilising pressurised fluid extraction (PFE) to simultaneously extract polycyclic aromatic hydrocarbons (PAHs) and their polar oxidation products from atmospheric particulate matter (PM) is presented. The PFE method is advantageous over the traditional Soxhlet extraction due to its lower solvent consumption (9 mL compared to 90 mL) and shorter extraction time (15 min versus 18 h). Seventy compounds including PAHs and polar PAH oxidation products containing carbonyl (oxy-PAHs), hydroxyl (hydroxy-PAHs), and carboxylic acid (carboxy-PAHs) groups were targeted in the extraction of two different PM matrices: wood smoke (WS) and diesel exhaust (DE) PM. The PFE method was optimised and then compared to Soxhlet extraction for both PM matrices. The overall amounts of PAHs and their derivatives extracted from WS PM were slightly higher for the optimised PFE method (1849 ± 21 and 1863 ± 25 µg g−1 with dichloromethane (DCM) and methanol (MeOH), respectively) than those obtained with Soxhlet extraction (1726 ± 33 and 1769 ± 22 µg g−1 with DCM and MeOH, respectively). For DE PM (standard reference material (SRM) 2975) the overall amounts extracted by both methods were similar (average of 165 ± 6 µg g−1), agreeing with previously published values. The detailed evaluation of extraction efficiencies for WS PM showed similar amounts for unfunctionalised PAHs (1100 µg g−1) for both methods and solvents. For DE PM the mass yields for PAHs using PFE with DCM (62 ± 1 µg g−1) were the highest and nearly 20% higher than those obtained with MeOH (53 ± 2 µg g−1). The total mass yields of carboxy and hydroxy-PAHs from WS PM were also similar (412 ± 18 and 407 ± 11 µg g−1) for PFE and Soxhlet with MeOH, and higher than when DCM was used (371 ± 5 and 379 ± 12 µg g−1 for PFE and Soxhlet, respectively). For both matrices, the PFE yields for oxy-PAHs were higher than those obtained with Soxhlet.

Pressurized fluid extraction (PFE) of valonea tannin with binary H2O–CO2 and ternary H2O–CH3OH–CO2 systems and phase equilibrium studies

In this study, the effect of binary and ternary systems, solvent/feed (S/F) ratio (20–100w/w), time (2–3h) and pressure (10–200bar) were tested with subcritical and supercritical CO2 to produce valonea tannin from acorn cups. The best yield of phenolic contents (PCs) of the valonea tannin (34.73±0.02wt%) was obtained by H2O/CO2 binary system under the conditions of S/F=100(w/w) at 100bar for 3h with supercritical CO2. Phase equilibria of H2O/CH3OH/CO2 ternary system with different solvent fractions at different temperatures and pressures were also imaged in the high pressure view cell, where liquid–liquid–vapor phase behaviors were observed for all ratios of H2O and CH3OH from 60 to 100°C and 60 to 250bar. High tannin content isolated in a short time will decrease the waste load and provide great advantage in terms of reducing the cost of the tannin used in leather industry.

Recovery of Biomolecules from Food Wastes — A Review

Food wastes are produced by a variety of sources, ranging from agricultural operations to household consumption. About 38% occurs during food processing. At present, the European Union legislation encourages the exploitation of co-products. This valorisation can be achieved through the extraction of high-value components such as proteins, polysaccharides, fibres, flavour compounds, and phytochemicals, which can be re-used as nutritionally and pharmacologically functional ingredients. Extraction can proceed according to solid-liquid extraction, Soxhlet extraction, pressurized fluid extraction, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, pulsed electric field extraction, and enzyme-assisted extraction. Nevertheless, these techniques cannot be used indiscriminately and their choice depends on the type of biomolecules and matrix, the scale processing (laboratory or industrial), the ratio between production costs and economic values of the compounds to be extracted. The vegetable wastes include trimmings, peelings, stems, seeds, shells, bran, residues remaining after extraction of oil, starch, sugar, and juice. The animal-derived wastes include wastes from bred animals, wastes from seafood, wastes from dairy processing. The recovered biomolecules and by-products can be used to produce functional foods or as adjuvants in food processing or in medicinal and pharmaceutical preparations. This work is an overview of the type and amounts of food wastes; food waste legislation; conventional and novel techniques suitable for extracting biomolecules; food, medicinal and pharmaceutical uses of the recovered biomolecules and by-products, and future trends in these areas.

Use of fluorinated polybrominated diphenyl ethers and simplified cleanup for the analysis of polybrominated diphenyl ethers in house dust

A simple, cost-effective method is described for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust using pressurized fluid extraction, cleanup with modified silica solid phase extraction tubes, and fluorinated internal standards. There are 14 PBDE congeners included in the method, some typically contained in the commercial mixtures used as flame retardants, and some which are not routinely reported in the peer-reviewed literature. A gas chromatographic–mass spectrometry instrumental method provides baseline separation in <20min, detection limits <20ng/g, and quantitation limits <60ng/g for most congeners. Method blanks contained an average concentration <9ng/g for all congeners except BDE209 which had an average around 40ng/g. Spiked samples showed good accuracy with relative percent difference (RPD) <7%, and good precision with relative standard deviation <22% for all congeners except BDE209. The method was applied to the analysis of a standard dust (NIST Standard Reference Material 2585) and showed good accuracy with RPD <25% except for BDE154. Overall, this method exhibited good performance characteristics in all categories including simplicity, cost, sensitivity, selectivity, accuracy, and precision.

Relevance of ions in pressurized fluid extraction of carbohydrates and phenolics from barley hull

The removal of total carbohydrates and phenolics from the hull of a new barley variety BT 584 using solid-liquid batch and aqueous pressurized fluid (ethanol or ionic liquid) extractions were evaluated. Using pressurized fluids, temperature was the most significant variable for the extraction of biocompounds from barley hull. The highest phenolics extraction (189.1±3.1mg/g hull) was obtained using pressurized aqueous ionic liquid while the highest carbohydrates extraction (450.3±7.8mg/g hull) was obtained using pressurized aqueous ethanol. The predicted solubility of ferulic acid and glucose in water, ionic liquid or carbonic acid, and the acid dissociation constant of the compounds studied allowed proposing an extraction mechanism based on biomass interaction with ionic species formed during pressurized fluid extraction. The anionic species facilitated removal of phenolics while the interaction of cationic/anionic species facilitated removal of carbohydrates from barley hull biomass.

Acrylamide: Formation, Occurrence in Food Products, Detection Methods, and Legislation

This review aims at summarizing the most recent updates in the field of acrylamide (AA) formation (mechanism, conditions) and the determination of AA in a number of foods (fried or baked potatoes, chips, coffee, bread, etc). The methods applied for AA detection [Capillary Electrophoresis-Mass Spectrometry (CE-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), Non-Aqueous Capillary Electrophoresis (NACE), High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Pressurized Fluid Extraction (PFE), Matrix Solid-Phase Dispersion (MSPD), Gas Chromatography-Mass Spectrometry (GC-MS), Solid-Phase MicroExtraction-Gas Chromatography (SPME-GC), Enzyme Linked Immunosorbent Assay (ELISA), and MicroEmulsion ElectroKinetic Chromatography (MEEKC) are presented and commented. Several informative figures and tables are included to show the effect of conditions (temperature, time) on the AA formation. A section is also included related to AA legislation in EU and US.

Recent Applications of Pressurized Fluid Extraction: Curcuminoids Extraction with Pressurized Liquids

Pressurized liquid extraction is a versatile technique that allows the extraction of natural bioactive compounds such as curcuminoids, compounds that have medicinal properties and responsible for the yellow color of turmeric. Generally, used as an analytical tool pressurized liquid extraction uses elevated temperatures (313 – 473 K) and moderate to high (3.5 – 20 MPa) pressures to facilitate and enhance the extraction process. Various features such as the use of smaller amounts of solvents, reduced extraction time and no exposure of the compounds to oxygen and light, give this technique advantages over traditional processes of solvent extraction. This review describes the fundamentals and parameters influencing the process of pressurized liquid extraction, exploring the latest developments and trends in the extraction of bioactive compounds such as curcuminoids. It also discusses the possibility of using near room temperature (313 K) and pressures in the range of 10 – 30 MPa as opposing to the use of high temperatures, in the extraction of pigments from plant material rich in starch.

Status and distributions of pesticides buried at five sites in Arusha and Mbeya regions, Tanzania

This study investigated the compositions and distributions of pesticides buried at five sites in Tanzania. Samples were collected from various depths up to 220 cm. The analytes in samples were extracted by pressurized fluid extraction. Labelled internal standards were used for identification and quantification. Clean-up of extracts was conducted by using column chromatographic techniques. Determination of the analytes was performed by using a high resolution GC–MS. The dominant compounds detected were 4,4'-DDT (dichlorodiphenyltrichloroethane), 2,4'-DDT, 4,4'-DDE, 2,4'-DDE, 4,4'-DDD, 2,4'-DDD, hexachlorocyclohexane (HCH) isomers (α-, β-, γ-, δ- and e-HCH), aldrin, dieldrin, endrin, pentachlorobenzene, hexachlorobenzene, pentachloroanisole, endosulfans, chlordanes, heptachlor and heptachloroepoxides. The highest concentrations of total DDT and total HCH ranged 5.2 to 5410 mg/kg dry weight (dw) and 1.4 to 42200 mg/kg dw, respectively, while the highest concentrations for other compounds varied from 1.1 to 7200 mg/kg dw. The results indicated aged contaminants but the rate of degradation was generally very slow. The concentrations of the compounds decreased with increase in distance from the burial points. There were variations in the distribution of the compounds among the sampling sites and depths; some showed even distribution or accumulation downwards indicating some risks for groundwater contamination. Key words: Buried pesticides, soil, Tanzania.

Energy Consumption Versus Antioxidant Activity of Pressurized Fluid Extracts from Pfaffia glomerata Roots

Conventional extraction techniques have been applied to obtain antioxidant extracts from Pfaffia glomerata roots, most of the times, using polar extracting solvents. Even if these techniques are able to provide extracts with antioxidant activities, more environmentally friendly techniques are nowadays preferred. Among them, supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) with green solvents have been widely applied to natural bioactive compounds extraction. The limitation of the use of pure supercritical CO2 for obtaining antioxidant extracts from Pfaffia glomerata roots was already demonstrated. When high amounts of modifier are added, the formation of a gas-expanded liquid is observed. This extracting solvent combines the advantages of the solvation properties of typical liquids and the transport properties of supercritical fluids, being an intermediate process between SFE and PLE, which can be called as pressurized fluid extraction (PFE). In this work, PFE of Brazilian ginseng (Pfaffia glomerata) roots were performed in order to obtain antioxidant extracts with potential applications in the pharmaceutical and food areas. Several CO2+ethanol mixtures (90:10 %, 50:50 % and 0:100 %, w/w) as extracting fluid were assayed. The effects of other two process parameters including pressure (10-20 MPa) and temperature (323-363 K) on the extraction yield, antioxidant activity and energy consumption per unit of manufactured product were investigated. PFE process was simulated using the SuperPro Designer simulation platform. The use of 10 % (w/w) of ethanol produced extracts with the highest antioxidant activity. On the other hand, higher temperature and ethanol percentage resulted in higher extraction yield and lower energy consumption per unit of manufactured product, while pressure did not affect any response variables. Copyright © 2013, AIDIC Servizi S.r.l.

Isolation by pressurised fluid extraction (PFE) and identification using CPC and HPLC/ESI/MS of phenolic compounds from Brazilian cherry seeds (Eugenia uniflora L.)

Brazilian cherry seeds are a waste product from juice and frozen pulp production and, the seeds composition was investigated to valorize this by-product. Compounds separation was performed with ethanol by pressurised fluid extraction (PFE). Here we determine the effect of temperature (T), static time (ST), number of cycles (C), and flush volume (VF) on the yield, composition and total phenolic content (TPC) of the seed extracts. T, ST and their interaction positively influenced yield and TPC. Extracts were fractionated by high performance liquid chromatography (HPLC) and centrifugal partition chromatography (CPC). The collected fractions characterizations were made by electrospray ionisation mass spectrometry (ESI/MS) and high resolution mass spectrometry (HRMS) indicated the presence of ellagic acid pentoside and deoxyhexose, quercitrin and kaempferol pentoside. All of these compounds have antioxidant properties and normally are found in plant extracts. These results confirm that Brazilian cherry seed extract is a potentially valuable source of antioxidants.

Particulate associated polycyclic aromatic hydrocarbon exhaust emissions from a portable power generator fueled with three different fuels – A comparison between petroleum diesel and two biodiesels

The fuel impact on the emission of more than 40 particulate associated polycyclic aromatic hydrocarbons (PAHs) in the molecular weight range 178–302Da were investigated. The fuels; neat diesel (EN 590), rape seed methyl ester (B100) and a 30% w/w blend thereof (B30) were tested on a portable power generator without any exhaust aftertreatment. Gaseous emissions of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) were measured along with particulate emissions and its size distribution for the different fuels. Collected diesel particles were extracted using pressurized fluid extraction and analyzed using an online hyphenated liquid chromatography–gas chromatography–mass spectrometry system.The neat B100 and the B30 fuel produced less CO and total PAHs while the emissions of NOx and particulate matter increased compared with petroleum diesel fuel per kWh. The reduction of PAH emissions of the alternative diesel fuels were 36% and 70% for B30 and B100 respectively. While the PAH profiles for the neat diesel fuel and B30 were similar, the profile of B100 differed in the sense that the emission contained a higher percentage of PAHs with higher molecular weights. The emission of these PAHs was however larger using the neat diesel fuel with the exception for some of these higher molecular weight PAHs of which there was an increased emission using B100. Thermogravimetric analysis revealed that the collected particles from B100 contained a substantial amount of volatile components. A mass spectrometric full scan analysis suggests that these volatile components are in fact unburned or partially-burned fuel constituents.It is concluded that the particles originating from biodiesel combustion might be very different from those originating from petroleum diesel combustion which places new demands on the development of measurement methodologies originally developed for particulate emissions from petroleum-based fuels.

Application of Pressurized Fluid Extraction Method to Lipids Extraction for Determining trans-Fatty Acid Contents in Food

Abstract trans-Fatty acid contents of lipids extracted from several foods by pressurized fluid extraction were analyzed and compared with those extracted by the conventional methods, Folch method, acid hydrolysis, and Soxhlet method. Extraction efficiency of lipids from commercially available cookies and brown rice by the pressurized fluid extraction was equivalent to those extracted by the other extraction methods. Furthermore, neither oxidative degradation nor new trans isomerization of unsaturated fatty acids during the pressurized fluid extraction could be found. These results suggest that the pressurized fluid extraction could be applicable as a useful lipid extraction method for determining trans-fatty acids in food.

A green and effective approach for characterisation and quality control of Chrysanthemum by pressurized hot water extraction in combination with HPLC with UV absorbance detection

Chrysanthemum is a ubiquitous plant with many species and wide uses, and it is usually consumed as functional food. The main aim of this paper is to demonstrate that chromatographic fingerprints obtained from the HPLC/UV analysis of the pressurized hot water extraction (PHWE) extracts together with the aid of principal component analysis (PCA), allowed for the clustering of various chrysanthemums of different species and provenance. In addition, a parallel study of pressurized fluid extraction (PFE) with methanol was carried out for comparison. From the results, a clearer separation and clustering was obtained with the environmentally-benign water extracts compared with methanol extracts. This study shows that PHWE in combination with HPLC/UV and PCA can be used successfully as a green and effective approach for characterisation and quality control of ubiquitous functional food such as chrysanthemum.

PRESSURIZED FLUID EXTRACTION OF RICE BRAN OIL USING A MODIFIED SUPERCRITICAL FLUID EXTRACTOR AND A CENTRAL COMPOSITE DESIGN FOR OPTIMIZATION

Rice bran is a by-product of rice processing, obtained through the polishing of rice grain. It illustrates the high considerable oil content (between 15–25%) and it is considered as an excellent source of nutritionally beneficial compounds. Pressurized fluid extraction (PFE) technique was used for extraction of oil from rice bran. The extracted samples planned by the central composite design were used to achieve 100% extraction yield under the following conditions. The temperature, pressure, extraction time and the solvent flow rate were adjusted 77°C, 75 bar, 34 min, and 0.2 mL/min, respectively. It is evident that free fatty acid content, iodine value and saponification value of the oil obtained by PFE is lower than hexane-extracted oil (Soxhlet). The results indicated that pressurized fluid extraction is a practical technique for extraction of rice bran oil.