Extraction of natural vitamin E from wheat germ by supercritical carbon dioxide

An efficient supercritical fluid extraction (SFE) process with carbon dioxide (SFE-CO(2)) was developed for the extraction of natural vitamin E (V(E)) from wheat germ. Both the pretreatment of extracted wheat germ and extraction conditions were optimized to ensure maximal V(E) yield. The extraction was undertaken at the extracting pressure of 4000-5000 psi, the extracting temperature of 40-45 degrees C, and the carbon dioxide flow rate of 2.0 mL/min for 90 min. An optimized pretreatment of wheat germ was usually necessary with a particle size of 30 mesh and a moisture content of 5.1%. A yield comparison of V(E) and its isomers extracted by supercritical CO(2) with those by conventional solvent extraction suggested that this SFE process was a practical process prospectively superior to conventional solvent extraction to prepare V(E) from wheat germ.     

Water activity effects on geranyl acetate synthesis catalyzed by novozym in supercritical ethane and in supercritical carbon dioxide

The esterification reaction of geraniol with acetic acid catalyzed by Novozym was studied in supercritical ethane (sc-ethane) and in supercritical carbon dioxide (sc-CO(2)). Water activity (a(W)) had a very strong effect on enzyme activity, with reaction rates increasing up to a(W) = 0.25 and then decreasing for higher a(W). Salt hydrate pairs could not prevent changes in a(W) during the course of reaction but were able to control a(W) to some extent and had a beneficial effect on both initial rates of esterification and conversion in sc-ethane. The enzyme was more active in sc-ethane than in sc-CO(2), confirming the deleterious effect of the latter already observed with some enzymes. Temperatures between 40 and 60 degrees C did not have a strong effect on initial rates of esterification, although reaction progress declined considerably in that temperature range. For the mixture of 50 mM acetic acid plus 200 mM geraniol, 100% conversion was achieved at a reaction time of 10 h at 40 degrees C, 100 bar, an a(W) of incubation of 0.25, and a Novozym concentration of 0.55 mg cm(-)(3) in sc-ethane. Conversion was below 50% in sc-CO(2) at otherwise identical conditions. With an equimolar mixture of the two substrates (100 mM), 98% conversion was reached at 10 h of reaction in sc-ethane (73% conversion in sc-CO(2)).     

Isomeric enhancement of davanone from natural davana oil aided by supercritical carbon dioxide

The chemical nature of davanone isolated from natural davana oil via packed column preparative supercritical fluid chromatography with a carbon dioxide-based mobile phase has been defined. Analyses used to characterize davanone included nuclear magnetic resonance spectroscopy, optical rotation, mass spectrometry, headspace solid-phase microextraction, enantiomeric purity via gas chromatography (GC), and GC-coupled olfactometry. For comparison, natural davana oil was subjected to the same types of measurements. The enriched davanone sample was nearly 100% optically pure. This indicates that fractionation of the davana oil with supercritical fluids at near room temperature had little effect on the optical integrity of the sample.     

Synthesis of carbonated fatty methyl esters using supercritical carbon dioxide

The two-step syntheses of the cyclic carbonates carbonated methyl oleate (CMO) and carbonated methyl linoleate (CML) are reported. First, synthesis of epoxides through well-precedented chemical reactions of unsaturated fatty methyl esters with hydrogen peroxide and formic acid was accomplished. Next, a carbonation reaction with a simple tetrabutylammonium bromide catalyst was performed, allowing the direct incorporation of carbon dioxide into the oleochemical. These syntheses avoid the use of the environmentally unfriendly phosgene. The carbonated products are characterized by IR, 1H NMR, and 13C NMR spectroscopy and studied by thermogravimetric analysis (TGA). Also reported is the synthesis of a similar cyclic carbonate from the commercially available 2-ethylhexyl epoxy soyate. These carbonates show properties that may make them useful as petrochemical replacements or as biobased industrial product precursors.     

Recovery of pigments from Origanum majorana L. by extraction with supercritical carbon dioxide

Extraction of pigments (chlorophylls and carotenoids) from marjoram (Origanum majorana L.) with supercritical carbon dioxide was investigated. The aim of this study was to map the effects of extraction pressure and temperature on the yield of coloring materials by applying a 3(2) full factorial design with three repeated tests in the center of the design. For comparison, laboratory and pilot plant Soxhlet extractions were carried out using ethanol and n-hexane solvents. The compositions of pigments in marjoram extracts were determined by HPLC. Similar amounts of carotenoids, in addition to 40% of chlorophylls and their derivatives, were recovered from the supercritical fluid extraction, in comparison to the ethanol Soxhlet extraction.     

Extraction of pharmaceutical components from Ginkgo biloba leaves using supercritical carbon dioxide

Ginkgo biloba extract (GBE) has many remarkable pharmacological and clinical effects, and it is the most frequently used product as a phytomedicine in many countries. The combination of primary extraction with 70% ethanol followed by extraction using supercritical carbon dioxide provides an efficient and economical means for obtaining flavonoids and terpenoids from Ginkgo biloba leaves. The supercritical fluid extraction (SFE) is affected by pressure, temperature, and the concentration of modifier in the extractant. At the most favorable experimental conditions of 300 MPa, 60 degrees C, and carbon dioxide containing 5% ethanol as modifier, the yield of GBE powder is 2.1% (based on the air-dry weight of Ginkgo biloba leaves) compared to a yield of only 1.8% by conventional solvent extraction. The contents of flavonoids and terpenoids in SFE products are 35.9% and 7.3%, respectively, which are significantly higher than the general standards of 24% and 6%, respectively.     

Acetylation of soybean lecithin and identification of components for solubility in supercritical carbon dioxide

There is a growing interest to develop environmentally friendly surfactants for utilization with supercritical carbon dioxide (scCO2), which is a "green" solvent with many industrial applications. The goal of the present work was to separate the commonly used soybean lecithin into a phospholipid-rich fraction, acetylate this fraction, and then test its solubility in scCO2 to gauge its suitability as a surfactant for potential scCO2-based applications. Soybean lecithin was first purified by fractionation using acetone and ethanol and then acetylated with acetic anhydride. The acetylated lecithin was further purified by fractionation with acetone to separate the acetylated fraction from the nonacetylated fraction. High-performance liquid chromatography and electrospray ionization mass spectrometry were utilized to characterize these fractions. The various acetylated phospholipid fractions were then tested for solubility in scCO2 under various pressures and temperatures using both a cloud-point and a Fourier transform infrared apparatus. Acetylation was found to increase the solubility of the phospholipids in scCO2, and N-acetylated phosphatidylethanolamine (NAc-PE) was found to be the most soluble component of the acetylated phospholipids.     

Enhanced supercritical fluid carbon dioxide extraction of pesticides from foods using pelletized diatomaceous earth

Supercritical fluid carbon dioxide (SC-CO2), when used with an extraction enhancer, comprises a supercritical fluid extraction (SFE) system for extraction of pesticides and matrix components from fatty and nonfatty foods. After being mixed with the enhancer, samples ranging from 95% water to pure lipophilic oils can be extracted efficiently with SC-CO2. This extraction technique yields analyte recoveries in excess of 85% for over 30 types of pesticides at incurred levels ranging from 0.005 to 2 ppm in such diverse matrixes as carrots, lettuce, peanut butter, hamburger, and fortified butter fat and fortified potatoes. SC-CO2 provides a solvent medium that is nontoxic, nonflammable, and inexpensive while also eliminating the use and disposal of potentially carcinogenic organic solvents.     

Comparison of eucalyptus camaldulensis Dehn. oils from Mozambique as obtained by hydrodistillation and supercritical carbon dioxide extraction

Leaf oils of E. camaldulensis Dehn. from Mozambique obtained by hydrodistillation and by supercritical carbon dioxide extraction under different conditions were compared with regard to their major components. The oil obtained by hydrodistillation showed high concentrations of 1,8-cineole (43%), alpha-pinene (5.5%), beta-pinene (3.4%), p-cymene (5.2%), terpinen-4-ol (3.1%), and globulol (4.1%). The extracts obtained by supercritical carbon dioxide extraction have lower amounts of 1,8-cineole, alpha-pinene, beta-pinene, and terpinen-4-ol, but have higher amounts of allo-aromadendrene and globulol. At the same time, distilled oil of E. radiata was extracted from an inert matrix (Celite) and the extract showed a higher content of 1,8-cineole at 80 bar and 60 degrees C than the feed, suggesting that a multiple-stage supercritical carbon dioxide extraction of the E. camaldulensis studied can produce an oil close to the market requirements set by the European pharmacopoeias.     

Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.     

Yield and composition of grape seed oils extracted by supercritical carbon dioxide and petroleum ether: varietal effects

Grape seed has a well-known potential for production of oil as a byproduct of winemaking and is currently produced as a specialty oil byproduct of wine manufacture. Seed oils from eight varieties of grapes crushed for wine production in British Columbia were extracted by supercritical carbon dioxide (SCE) and petroleum ether (PE). Oil yields by SCE ranged from 5.85 +/- 0.33 to 13.6 +/- 0.46% (w/w), whereas PE yields ranged from 6.64 +/- 0.16 to 11.17 +/- 0.05% (+/- is standard deviation). The oils contained alpha-, beta-, and gamma-tocopherols and alpha- and gamma-tocotrienols, with gamma-tocotrienol being most important quantitatively. In both SCE- and PE-extracted oils, phytosterols were a prominent feature of the unsaponifiable fraction, with beta-sitosterol quantitatively most important with both extractants. Total phytosterol extraction was higher with SCE than with PE in seven of eight variety extractions. Fatty acid composition of oils from all varieties tested, and from both extraction methods, indicated linoleic acid as the major component ranging from 67.56 to 73.23% of the fatty acids present, in agreement with literature reports.     

Extraction of natural complex phenols and tannins from grape seeds by using supercritical mixtures of carbon dioxide and alcohol

Proanthocyanidins are supposed to have some therapeutical properties as antioxidants and antineoplasics. Most of the proanthocyanidins, however, are not commercialized since their separation from natural sources is either very expensive or not well-known. In this work, the feasibility of application of mixtures of carbon dioxide and alcohol under supercritical conditions for selective extraction of some phenolic compounds from grape seeds has been studied, among them some low polymerized proanthocyanidins, their main monomer units, (+)-catechin and (-)-epicatechin, and some low molecular weight phenolic compounds, like gallic acid. An analytical-scale supercritical fluid extractor, whose operation was previously optimized, was used to carry out the experiments. A commercial concentrate of complex phenols and tannins from grape seeds was subjected to supercritical extraction in order to find the best operation conditions before directly extracting defatted milled grape seeds. The solvent capacity was found to increase with pressure and with the amount of alcohol used as cosolvent as expected. Such variation in solvent capacity could be used for design of a selective separation process where individual phenolic compounds or groups of them could be obtained. HPLC coupled with two types of detectors, diode array and mass spectrometry, was used for tentative identification and quantification of complex phenols and tannins in the extracts and in the raw materials used for extraction.     

Use of adsorbent and supercritical carbon dioxide to concentrate flavor compounds from orange oil.

Orange oil is composed largely of terpene hydrocarbons but is a source of flavor and fragrance compounds (oxygenated) that are present in low concentrations. To increase the ratio of oxygenated compounds to terpene hydrocarbons, orange oil was partially fractionated by adsorption of the oxygenated compounds onto porous silica gel, with full utilization of its adsorbent capacity, and then further purified by desorption into supercritical carbon dioxide. The desorption of 24 compounds was monitored by GC and GC-MS. Adsorption alone removed three-fourths of the terpene hydrocarbons, and fractional extraction by supercritical carbon dioxide (SC-CO(2)) improved the separation further. Response surface methodology was used in the experimental design, and regression analysis was used to determine the effects of process variables. Extraction at low temperatures and flow rates improved separation by SC-CO(2). Decanal was concentrated to 20 times that of the feed oil by using SC-CO(2) at 13.1 MPa, 35 degrees C, and 2 kg/h. The systems were operating at close to equilibrium conditions because of the fine dispersal of the oils and the excellent mass transfer properties of supercritical carbon dioxide.     

Anti-inflammatory effects of supercritical carbon dioxide extract and its isolated carnosic acid from Rosmarinus officinalis leaves

Rosemary (Rosmarinus officinalis) leaves possess a variety of bioactivities. Previous studies have shown that the extract of rosemary leaves from supercritical fluid extraction inhibits the expression of inflammatory mediators with apparent dose-dependent responses. In this study, three different extraction conditions (5000 psi at 40, 60, and 80 °C) of supercritical carbon dioxide (SC-CO(2)) toward the extraction of antioxidants from rosemary were investigated. Furthermore, simultaneous comparison of the anti-inflammatory properties between rosemary extract prepared from SC-CO(2) under optimal conditions (5,000 psi and 80 °C) and its purified carnosic acid (CA) using lipopolysaccharide (LPS)-treated murine RAW 264.7 macrophage cells was also presented. Results showed that the yield of 3.92% and total phenolics of 213.5 mg/g extract obtained from the most effective extraction conditions showed a high inhibitory effect on lipid peroxidation (IC(50) 33.4 μg/mL). Both the SC-CO(2) extract and CA markedly suppressed the LPS-induced production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), phosphorylated inhibitor-kappaB (P-IκB), and nuclear factor-kappaB (NF-κB)/p65 in a dose-dependent manner. The five major compounds of verbenone, cirsimaritin, salvigenin, carnosol, and CA existing in the SC-CO(2) extract were isolated by semipreparative HPLC and identified by HPLC-MS/MS analysis. CA was the most abundant recorded compound and the most important photochemical with an anti-inflammatory effect with an IC(50) of 22.5 μM or 7.47 μg/mL presented to the best inhibitory activity on NO production better than that of the 14.50 μg/mL dosage prepared from the SC-CO(2) extract. Nevertheless, the effective inhibition of LPS-induced NF-κB signaling in RAW 264.7 cells from the SC-CO(2) extract extends the potential application of nutraceutical formulation for the prevention of inflammatory diseases.     

Riboflavin-sensitized photochemical changes in beta-lactoglobulin in an aqueous buffer solution as affected by ascorbic acid

The effects of ascorbic acid on the riboflavin-sensitized photochemical changes in beta-lactoglobulin in an aqueous buffer solution as determined by high performance gel permeation liquid chromatography (HPGPLC), insoluble protein content, and individual amino acid content during fluorescent light illumination were studied. The riboflavin-sensitized photochemical degradation of beta-lactoglobulin was effectively inhibited by ascorbic acid, and its inhibitory effectiveness was concentration dependent. The 0.1% ascorbic acid treatment showed 74.4% inhibition of beta-lactoglobulin degradation as determined by a HPGPLC during 6 h light illumination. Insolubility of beta-lactoglobulin in a buffer solution during light illumination was also effectively decreased by ascorbic acid treatment. The riboflavin-sensitized photochemical reduction of cysteine, histidine, lysine, methionine, and tryptophan in beta-lactoglobulin was high during 6 h fluorescent light illumination. The 0.1% ascorbic acid treatment exhibited 20.8% inhibition of total amino acid degradation in beta-lactoglobulin during 6 h light illumination, showing strong inhibitory activity against the degradation of arginine, aspartic acid, cystein, glycine, histidine, phenylalanine, proline, serine, and tryptophan.     

Isolation of anacardic acid from natural cashew nut shell liquid (CNSL) using supercritical carbon dioxide

Solvent extracted cashew nut shell liquid (CNSL), conventionally known as natural CNSL, is a mixture of several alkenyl phenols. One of these alkenyl phenols is anacardic acid, which is present at the highest concentration. In view of anticipated industrial applications of anacardic acid, the objective of this work was to isolate anacardic acid from natural CNSL by supercritical carbon dioxide (scCO 2). In this study, the solubility data for natural CNSL in scCO 2 under a range of operating conditions of pressure (100, 200, and 300 bar), temperature (40 and 50 degrees C), and CO 2 flow rate (5, 10, and 15 g min (-1)) were established. The best scCO 2 working conditions were found to be 50 degrees C and 300 bar at a flow rate of 5 g min (-1) CO 2. Using 3 g of sample (CNSL/solid adsorbent = 1/2) under these scCO 2 conditions, it was possible to quantitatively isolate high purity anacardic acid from crude natural CNSL (82% of total anacardic acid) within 150 min. The anacardic acid isolated by scCO 2 was analyzed by different spectroscopic techniques (UV-vis, FT-IR, and (1)H NMR) and HPLC analysis, indicating that the anacardic acid isolated by scCO 2 has better quality than that obtained through a conventional method involving several chemical conversion steps.     

Extraction of lycopene from tomato skin with supercritical carbon dioxide: effect of operating conditions and solubility analysis

Supercritical carbon dioxide (SCCO2) extraction of lycopene from waste tomato skins was investigated. The experiments were carried out at pressures and temperatures ranging from 20 to 50 MPa and 313 to 373 K, respectively, without any modifiers. The flow rate of CO2 was maintained at 2.5 mL/min for 330 min extraction time. Solvent flow rate effect was examined for CO2 flow rates from 1.5 to 4.5 mL/min. The extracts were analyzed by high-performance liquid chromatography and UV-visible spectroscopy. The results showed that with optimized operating conditions, the maximum yield of lycopene (1.18 mg of lycopene/g of sample) was obtained at 40 MPa, 373 K, and 2.5 mL of CO2/min. Chromatographic analysis indicated that lycopene was extracted from tomato skin with negligible degradation at the optimum conditions and the amount extracted represented more than 94% of the total carotenoid content of the sample. The solubility of lycopene was modeled by use of the Chrastil equation.     

Photoacoustic detection of orthophosphate in aqueous solution

The photoacoustic spectroscopy at 633 nm wavelength of a 8 mW He-Ne laser has been used to measure the concentration of orthophosphate dissolved in distilled water. Determination is achieved through the combined use of the colorimetric molybdenum blue method with the high detection sensitivity offered by the photoacoustic technique. A concentration of 1 mmol m^?3 (96 ppb) orthophosphate could readily be detected with the relatively simple experimental set-up.     

Abiotic degradation of iodosulfuron-methyl-ester in aqueous solution

The abiotic degradation of iodosulfuron-methyl-ester was investigated under both alkaline and acidic pH conditions in the dark, and results showed it to be a rather stable molecule in neutral or slightly alkaline environments. Photochemical reactions were studied using a high-pressure mercury arc lamp, and results showed that direct phototransformation is possible under normal environmental conditions (lambda > 290 nm). High-performance liquid chromatography (HPLC-UV and HPLC-MS) analyses were used to identify the degradates and to study the kinetics of photodecomposition and hydrolysis. Five main products of iodosulfuron-methyl-ester degradation were tentatively identified, and one of them (4-methoxy-6-methyl-1,3,5-triazin-2-amine) was confirmed using an authentic standard. Among the phototransformation mechanisms, photosubstitution of the iodide atom by a hydroxyl group, photodissociation of the N-S bond, and photoassisted hydrolysis were observed. The quantum efficiencies (multiwavelength quantum yield) of the photodegradation under different conditions were determined, and values of 0.054 +/- 0.02 (pH 9.6), 0.08 +/- 0.02 (pH 7), and 0.044 +/- 0.008 (pH 5.3) were obtained.     

Photochemical degradation of acifluorfen in aqueous solution

To elucidate the photochemical behavior of diphenyl ether herbicides in superficial waters, the photodegradation of acifluorfen, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzo?c acid (CAS Registry No. 50594-66-6), was studied in water and acetonitrile. All experiments were carried out under laboratory conditions using a solar simulator (xenon arc) or jacket Pyrex reaction cell equipped with a 125 W high-pressure mercury lamp. The calculated polychromatic quantum efficiencies (Phi(solvent)) of acifluorfen in different solvents are as follows (units are degraded molecules photon(-1)): Phi(water) = 10(-4), Phi(acetonitrile) = 10(-4), Phi(methanol) = 10(-4), and Phi(hexane) = 10(-2). The results obtained in this work are in good agreement with the literature value of monochromatic quantum yield. HPLC-MS analysis (APCI and ESI in positive and negative modes) was used to identify acifluorfen photoproducts. These results suggest that the photodegradation of acifluorfen proceeds via a number of reaction pathways: (1) decarboxylation, (2) dehalogenation, (3) substitution of chlorine group by hydroxyl or hydrogen groups, and (4) cleavage of ether linkage, giving phenols. Photorearrangement products were studied by other investigators. No such products were observed. In addition, it was found that the trifluoro functional group on acifluorfen was not affected by any transformation, and no products of a nitro group reduction were found.