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  • 1
    Electronic Resource
    Electronic Resource
    Extended x-ray absorption fine structure investigation of solid and gel forms of calcium poly(+.alpha.-D-galacturonate) (1986)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 90 (1986), S. 6853-6857 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100284a029
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  • 2
    Electronic Resource
    Electronic Resource
    Simulation and Analysis of Fluid Dynamic Behaviour of Foods during Filling Processes (2007)
    Berkeley, Calif. : Berkeley Electronic Press (now: De Gruyter)
    Chemical product and process modeling 2 (2007), S. 18 
    Details
    ISSN: 1934-2659
    Source: Berkeley Electronic Press Academic Journals
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This research presents a model describing the behaviour of a non-Newtonian shear-thinning fluid during aseptic filling processes, in order to determine the influence of the behaviour of fluids on the performance of filling valves in aseptic beverage plants, mainly in terms of the time required to perform the filling process. The ultimate aim of the study is to explore the possibility of improving the accuracy of industrial filling processes, so as to be able to utilise them with high viscosity fluids.The numerical model, exploiting the Finite Elements Method (FEM), was designed using the commercial software Comsol Multiphysics, and validated by comparing the steady state predictions with outcomes of filling experiments performed in industrial laboratories. Hence, subsequent numerical simulations were performed to investigate the transition from laminar to turbulent flow for shear-thinning fluids under different pressure conditions, in 3D time-dependent configurations. Results of the simulations, performed on a low fat yoghurt, show that laminar flow subsists within the whole filling system when the Metzner-Reed Reynolds number at the inlet section of the valve is lower than approx 444.
    Type of Medium: Electronic Resource
    URL: http://www.bepress.com/cppm/vol2/iss3/18
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  • 3
    Electronic Resource
    Electronic Resource
    Microbiological characterisation of Burkholderia cepacia isolates from cystic fibrosis patients: investigation of the exopolysaccharides produced (2002)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 209 (2002), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Eleven strains of Burkholderia cepacia were isolated directly from clinical specimens: 10 from sputum of cystic fibrosis patients, and one from a vaginal swab. They were biochemically identified using API20NE and confirmed by a PCR-based assay. The genomovar characterisation obtained by specific PCR amplification revealed seven strains belonging to genomovar I, three belonging to genomovar IIIA and one belonging to genomovar IV. All isolates were also typed by ribotyping and random amplification of polymorphic DNA analysis. Some of the characterised strains were examined for the ability to produce exopolysaccharides, with the aim of correlating the genomovar with the exopolysaccharide structure. The polysaccharides were analysed by means of methylation analysis and 1H-NMR spectroscopy in order to determine structural similarities. It was shown that different strains are capable of producing chemically different polysaccharides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2002.tb11116.x
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  • 4
    Electronic Resource
    Electronic Resource
    1H- and13C-NMR spectroscopic studies of lipid extracts of the red algaGracilaria longa (1992)
    Springer
    Journal of applied phycology 4 (1992), S. 149-155 
    Details
    ISSN: 1573-5176
    Keywords: red alga ; lipid extract ; 1H-NMR ; 13C-NMR ; Gracilaria longa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lipid extracts of the red algaGracilaria longa were studied by1H- and13C-NMR spectroscopy. Peaks in the13C-NMR spectra attributable to sterols, chlorophylls and carotenoids allowed free and acylated cholesterol, chlorophylla and lutein to be identified as the most abundant components of these classes. A content of 0.5 ± 0.1 μmoles of total cholesterol/g wet alga was estimated from the1H-NMR spectrum, which also allowed the determination of the phosphatidylcholine/total lipid molar ratio (9.5 ± 0.5%). The13C-NMR spectroscopic experiments provided information on the position of the double bonds on the fatty acid residues. A comparison between NMR spectra of lipid extracts obtained for wet and dried alga showed that the alga undergoes both a dramatic peroxidation and some glycolipid degradation during the drying process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442463
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  • 5
    Electronic Resource
    Electronic Resource
    Modified procedures for extraction and analysis of carrageenan applied to the red alga Hypnea musciformis (1995)
    Springer
    Journal of applied phycology 7 (1995), S. 565-576 
    Details
    ISSN: 1573-5176
    Keywords: Rhodophyta ; red alga ; Hypnea musciformis ; carrageenans ; extraction ; kappa-carrageenase ; oligosaccharides ; fractionation ; NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dried powder of Hypnea musciformis was extracted with water at pH 7 after an initial short pre-treatment with cold, diluted HCl. Carrageenans were isolated by alcohol precipitation after an amylase treatment and a filtration of the extracts. The yields at 25 and 90 °C were 25 and 75% (w/w) of the dry alga, with molecular weights (Mw) corresponding to 194 000 and 245 000, respectively. The chemical structure was dominated by G4S-DA-(kappa-carrageenan or carrageenose 4′-sulphate). A simple fractionation procedure for kappa-carrageenase hydrolysates, based on stirring in different enthanol/water mixtures, is introduced. NMR analysis showed that oligosaccharides with a repeating DA-G4S structure were the main constituents in the enzymic hydrolysates of the carrageenans from Hypnea musciformis. These oligosaccharides were solubilized in an ethanol concentration from 96 to 48% (v/v). In some enzyme resistant fractions D6S-G4S and DA2S-G4S sequences and D2S,6S unites were detected by 13C-NMR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003944
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  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of steam explosion as pretreatment in agar extraction fromGracilaria dura (C. Agardh) J. Agardh (Gracilariaceae, Rhodophyta) (1993)
    Springer
    Journal of applied phycology 5 (1993), S. 417-424 
    Details
    ISSN: 1573-5176
    Keywords: steam explosion ; agar ; Gracilaria dura ; Gracilariaceae ; Rhodophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Steam explosion was investigated as a pretreatment step in the isolation of agar from the macroalgaGracilaria dura. As compared to conventional procedures, the yield of agar obtained using this method on alkali (Na2CO3) conditioned algal material was higher. Extractions performed first at 95 °C and then at 121 °C showed that the major fraction of the agar was extracted at 95 °C, independently of the pretreatment. The efficiency of sulphate hydrolysis during steam explosion ofG. dura previously conditioned in Na2CO3, was similar to that of a NaOH based alkali pretreatment. Except for a lower nitrogen content of the sample obtained after NaOH based alkali pretreatment and a higher 6-O-methyl-β-d-galactose content in the agar after steam explosion, the chemical composition of the agars showed no significant difference. Agars extracted after steam explosion had melting temperature, gel strength and apparent modulus of elasticity lower than those of corresponding ‘native’ and alkali (NaOH) pretreated samples, but comparable to those of a commercial sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182734
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  • 7
    Electronic Resource
    Electronic Resource
    Lipid extracts from different algal species:1H and13C-NMR spectroscopic studies as a new tool to screen differences in the composition of fatty acids, sterols and carotenoids (1992)
    Springer
    Journal of applied phycology 4 (1992), S. 315-322 
    Details
    ISSN: 1573-5176
    Keywords: lipid extract ; 1H-NMR ; 13C-NMR ; carotenoids ; polyunsaturated fatty acids ; Ulva rigida ; Gracilaria longa ; Fucus virsoides ; Codium tomentosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One- and two-dimensional1H- and13C-NMR spectra of lipid extracts fromUlva rigida, Gracilaria longa, Fucus virsoides andCodium tomentosum collected in the northern Adriatic Sea allowed screening of the content of fatty acid chains, carotenoids, free and acylated cholesterol and chlorophylls. The carotenoid-to-polyunsaturated fatty acid molar ratio was taken as a comparison parameter in samples ofUlva rigida collected in differentloci and seasons; the value was markedly higher in samples from the Lagoon of Venice than from marine coastal waters. The total cholesterol concentration was evaluated by1H-NMR spectroscopy and similar values were found for all species. Two-dimensional heterocorrelated NMR spectroscopy was shown to give characteristic fingerprints of the lipid extracts from algal samples as regards the content in chlorophylls, unsaturated fatty acids and carotenoids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185788
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  • 8
    Electronic Resource
    Electronic Resource
    Structure and properties of agar from two unexploited agarophytes from Venezuela (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 497-500 
    Details
    ISSN: 1573-5117
    Keywords: agar ; Gelidiella acerosa ; Gracilaria mammillaris ; red algae ; red seaweed ; sulphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The red seaweeds Gelidiella acerosa and Gracilaria mammillaris growing along the coast of Venezuela were investigated as potential economic sources of agar. Agar extracted from Gracilaria mammillaris accounted for 27% of the algal dry weight but had quite a poor gelling ability because of the presence of alkali-stable sulphate groups on the D-galactose residue. However, the gel strength of its aqueous solutions was considerably enhanced by the addition of potassium, sodium and calcium ions (up to 1N). On the contrary, the galactan from Gelidiella acerosa (yield of about 20% w/w) exhibited quite good properties. In particular, the gel strength was comparable to that of commercial agaroses. Sulphate esters were not detectable by chemical methods and NMR spectroscopy revealed an agarose backbone with a high degree of methylation on both D and L-galactose residues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047851
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  • 9
    Electronic Resource
    Electronic Resource
    C6-oxidized cellulose: Ion interactions with mono- and divalent cations (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 157-163 
    Details
    ISSN: 0006-3525
    Keywords: chemical oxidation ; cellulose ; conformational transition ; capillary viscosity ; microcalorimetry ; calcium ions ; gels ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational behavior of different molecular weight fractions of a synthetic C6-oxidized derivative of cellulose were investigated by means of capillary viscometry, CD, and microcalorimetric measurements. Experiments were carried out in the presence of either monovalent or divalent counterions.The experimental data indicated that C6-oxidized cellulose can assume an ordered extended conformation at low ionic strength, induced by the intrachain repulsions of negative charges. This conformation was suggested to be very similar to the fully extended structure of cellulose. In addition to this, upon increasing the ionic strength, a conformational transition of the order-to-disorder type occurred. In fact, the screening of the electrostatic repulsions introduced a number of conformational kinks into the cellulosic backbone, which enabled the polymer to assume a more coiled conformation hence producing less viscous aqueous solutions. © 1998 John Wiley & Sons, Inc. Biopoly 45: 157-163, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Macroion-counterions interactions in dilute aqueous solution of iota- and kappa-carrageenan segments (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 757-764 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Interactions of counterions with segmented kappa- and iota-carrageenan sulfated polysaccharides were investigated by means of microcalorimetric and potentiometric measurements in dilute aqueous solution. The condensation of counterions onto the charged polymer chains leads, in general, to conformational transitions of the disorder-to-order type. A difference in the ability of different pairs of ionic species (monovalent/divalent counterions) to induce conformational transitions of carrageenate salts is demonstrated.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021850412
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