| 1. |
- da Cruz Francisco, José, et al.
(författare)
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Application of supercritical carbon dioxide for the extraction of alkylresorcinols from rye bran
- 2005
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 35:3, s. 220-226
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Tidskriftsartikel (refereegranskat)abstract
- The use of supercritical CO, (SC-CO2) for extracting alkylresorcinols from rye bran was investigated. For pure SC-CO2, 35 MPa and 55 degrees C were used. SC-CO2 with 10% ethanol or methanol as co-solvents was tested at four pressure levels (8, 15, 30 and 35 MPa) and two temperatures (40 and 55 degrees C). Experiments were conducted at a constant SC-CO2 flow of 5 g/min for 2 h. For comparative purposes acetone at ambient temperature and pressure was also used for extraction. The best extractions were achieved when SC-CO2 was used with co-solvents. At 55 degrees C and 15-30 MPa, the use Of SC-CO2 with co-solvents has yielded from 8 to 80% (w/w) more extracted product than acetone. Yield of extracts was proportional to pressure (when above 30 MPa) and temperature. The results suggest that cleaner bran extracts can be obtained by using pure SC-CO2 followed by the addition of co-solvents. There is no clear advantage of using either methanol or ethanol. (c) 2005 Elsevier B.V. All rights reserved.
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| 2. |
- da Cruz Francisco, José, et al.
(författare)
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Extraction of rye bran by supercritical carbon dioxide: Influence of temperature, CO2, and cosolvent flow rates
- 2005
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 53:19, s. 7432-7437
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Tidskriftsartikel (refereegranskat)abstract
- Process parameter optimization for the supercritical CO2 extraction of rye bran to obtain alkylresorcinols (AR) was studied by carrying out a two-level fractional design experiment. Four parameters, temperature, CO2 flow rate, cosolvent percentage, and extraction time, presumed to influence the extraction process, were analyzed. A tentative fractionation of the crude extract was also carried out and is discussed. The best extracts were achieved when the CO2 flow rate and extraction time or temperature and cosolvent addition were kept high. It was found that temperature increase was not statistically significant within the range of the study performed, and the extraction time was thus the most important factor. A preliminary fractionation process in two cyclone separators yielded two fractions, one rich in AR components with higher molecular weights and the other rich in AR components with low molecular weight.
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| 3. |
- da Cruz Francisco, José, et al.
(författare)
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Isolation of alkylresorcinols: Classical and supercritical CO2 extraction methods
- 2006
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Ingår i: Modern Extraction Techniques: Food and Agricultural Samples (ACS Symposium). - 0097-6156. - 9780841239401 - 0841239401 ; 926, s. 51-61
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter focuses on the use of different methods for isolation of alkylresorcinols. Alkylresorcinols are members of a lipid group called non-isoprenoid phenolic lipids. Different aspects of the extraction by classical methods and supercritical CO2 are discussed. Supercritical CO2 extraction of alkylresorcinols from rye bran is discussed for the first time. As compared to the classical extraction methods, supercritical CO2 gives higher yields and it allows the separation of the crude extrac into long- and short-chain alkylresorcinol homologues.
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| 4. |
- da Cruz Francisco, José, et al.
(författare)
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Supercritical Carbon Dioxide in the Biotechnology of Amphiphiles
- 2005
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Ingår i: Cellular & Molecular Biology Letters. - 1689-1392. ; 10:Suppl. 1, s. 105-105
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Tidskriftsartikel (refereegranskat)abstract
- This article is an overview, introducing the currently used supercritical carbon dioxide (scCO2) based technology in association to biotechnological applications. Within each application, the basic principles of the technique, a description of the instrumentation, methodology, and problems encountered, and advantages over the traditional methods are discussed. The areas covered in this paper include pure supercritical CO2 properties, coـsolvents role, and the interactions between the scCO2 and the amphiphiles involved. Extraction and reaction are discussed.
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| 5. |
- Dey, Estera, et al.
(författare)
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A food grade approach for the isolation of major alkylresorcinols (ARs) from rye bran applying tailored supercritical carbon dioxide(scCO(2)) extraction combined with HPLC
- 2009
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 51:2, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- Tailored supercritical carbon dioxide (scCO(2)) extraction of alkyhesorcinols (ARs) from rye bran resulting in pre-purification of ARs already during extraction process. The pre-purification was achieved by splitting the extraction process in 2 steps.. In both steps, the CO2 pressure was set at 25 MPa with a flow rate of 10 g/min. The first step was carried out at 70 degrees C. 0.06% of ethanolic co-solvent for 2 h, followed by the second step at 45,C using 10% of ethanolic co-solvent for 4 h, resulting in a pre-purified ARs extract. From the pre-purified scCO(2) extract, chromatographed on C8 column, were obtained pure ARs homologues of C17, C19 and C21 (68% of total) eluting separately in a linear gradient of ethanol. Additionally, a rapid method for the isolation of high purified pools of ARs homologues using a disposable solid phase extraction SPE-C18 column and a step gradient of ethanol was developed. (C) 2009 Elsevier B.V. All rights reserved.
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| 6. |
- Dey, Estera, et al.
(författare)
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A novel approach for characterization of exopolymeric material in sewage sludge
- 2006
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Ingår i: Journal of Residuals Science and Technology. - 1544-8053. ; 3:2, s. 97-103
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Tidskriftsartikel (refereegranskat)abstract
- The digestibility of sludge is dependent on the content of organic extra-cellular polymeric substances. Currently the most appropriate and rapid assessment methods for the organic content of wastewater are the chemical oxygen demand and volatile solids values. These parameters also measure the non-biodegradable organics. We have developed a method to predict sewage sludge digestibility and the appropriate composition of enzymes needed. Sludge is treated with selected enzymes and the released products characterized using a lectin panel. One protease and several glycosidases were selected and applied under mild conditions to minimize lysis of cells in the sludge. Combinations of enzymes with and without sodium triphosphate pentabasic were studied. Partially enzymaticaly hydrolyzed extra-cellular polymeric substances and the released glycoconjugates were quantitatively determined by conventional methods. Surface plasmon resonance was used to investigate the interaction of extracts with a lectin panel.
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| 7. |
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| 8. |
- Dey, Estera, et al.
(författare)
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The Cytotoxic and Genotoxic Effects of Conjugated Trans-2-Nonenal (T2N), an Off-Flavor Compound in Beer and Heat Processed food Arising from Lipid Oxidation
- 2005
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Ingår i: Polish Journal of Microbiology. - 1733-1331. ; 54:Supplement, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the toxic effect of E(2)nonenal (trans-2-nonenal, T2N) and its conjugate with horse muscle myoglobin (Mb) tested on murine cell line L929 and human cell line A549, as well as the genotoxic effect of these compounds assayed by measuring of micronuclei in human cells K562. It is an aldehyde, which is occurring as the substance responsible for an off flavour in aged beers, but originates also from lipid oxidation in heat processed food. T2N is an aldehyde formed from linoleic acid as a secondary oxidation product. The modification of Mb with T2N was analyzed with the use of SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and electrospray ionization mass spec-trometry (ESI-MS). Results from SDS-PAGE suggest that T2N substitutes Mb and additionally causes cross-linking with polymerization of Mb resulting in an insoluble fraction. The ESI-MS spectrum of the soluble fraction used in the toxicity tests, demonstrated that conjugation of T2N with Mb yielded Mb adducts with one residue of trans-2-nonenal per myoglobin molecule as the major fraction and adducts with different numbers of T2N molecules as minor fractions. In the cytotoxicity assay the T2N and its Mb conjugate causes 50% destruction of cells at the concentration 95-125 mg/ml and 200 mg/ml respectively, when L929 and A549 cell lines were used, whereas Mb control tested up to 2000 mg/ml was without any cytotoxic effect. In genotoxicity in vitro assay we have observed that the T2N and its Mb conjugate expressed the genotoxicity. The number of micronuclei in human K562 cells reached 26±2.16 promille (MN/1000 cells), comparing to 62 ± 8.64 MN/1000 cells for the reference free T2N, whereas a control value was 10.33 ±1.25 MN/1000 cells. The studied compounds expressed also the apoptotic effect in K562 cells as the number of apoptotic cells increased to 44.67 ±4.92 promille for T2N-Mb, comparing to 168.67 ±37.28 promille for free T2N, whereas a control value was 30.33 ± 1.36 promille for Mb. In these assays the T2N-Mb conjugate is several times more toxic in relation to control protein. Results indicate that T2N adducts with protein are potent to induce various cytotoxic and apoptotic effects when assayed in vitro tests. It suggests that higher level of such aldehyde might create in organism severe potential of toxicity.
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| 9. |
- Iheozor-Ejidor, Pamela, et al.
(författare)
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Extraction of rosavin from Rhodiola rosea root using supercritical carbon dioxide with water
- 2009
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 50:1, s. 29-32
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a new extraction method for the isolation of rosavin from dried crushed roots of Rhodiola rosea is being developed using supercritical CO2 and water. Rosavin extracts quantitatively and qualitatively were compared to commonly used solvents such as methanol, ethanol and ethyl acetate. By HPLC analysis rosavin was found to be the dominant compound in extracts obtained by both extraction methods. Quantitative differences were observed between the two extraction methods. Among the solvents, methanol yielded 3.3% while ethanol only 1.2% of rosavin. Supercritical CO2 and water at extraction temperature 80 degrees C and 5 h yielded 4.5% of rosavin. (C) 2009 Elsevier B.V. All rights reserved.
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| 10. |
- Landberg, Rikard, et al.
(författare)
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Comparison of supercritical carbon dioxide and ethyl acetate extraction of alkylresorcinols from wheat and rye
- 2007
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Ingår i: Journal of Food Composition and Analysis. - : Elsevier BV. - 0889-1575. ; 20:6, s. 534-538
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the application of supercritical carbon dioxide extraction of alkylresorcinols (AR) was quantitatively and qualitatively compared to a commonly used ethyl acetate extraction procedure. No difference in total AR content, relative homolog composition or total extract yield was found between the two extraction methods. Ethyl acetate extraction of intact wheat and rye kernels yielded only 9-20% of the total extract weight obtained with milled samples, but the same amount of alkylresorcinols, showing the benefit of analyzing intact grains whenever it is possible. The major compounds in all extracts (R-f = 0.8) were fatty acids in esterified form, most probably fatty acid alcohol esters. The two different extraction techniques produced comparable results under the conditions used, which suggests that issues other than performance need to be considered when choosing an appropriate technique. (c) 2007 Elsevier Inc. All rights reserved.
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