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Ghannam MT, Selim MYE, Zekri AY, Esmail N. Rheological Assessment of Oil-Xanthan Emulsions in Terms of Complex, Storage, and Loss Moduli. Polymers (Basel) 2023; 15:polym15020470. [PMID: 36679350 PMCID: PMC9860547 DOI: 10.3390/polym15020470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/28/2022] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
This experimental assessment was carried out to study the viscoelastic performance of crude oil-xanthan emulsions employing a RheoStress RS100 rheometer. Crude oil with a concentration range of 0−75% by volume was used to prepare the oil-gum emulsions. Two xanthan gums of Sigma and Kelzan were added in the emulsions with concentration ranges of 0−104 ppm. The linear viscoelastic ranges of all the tested oil-gum emulsions were found in the range of 0.1−10 Pa. Thus, the experimental tests were completed within the linear viscoelastic range of 1 Pa. The complex modulus increased gradually and steadily with frequency and gum concentration for all the examined emulsions. The addition of crude oil into the lighter xanthan concentration of <103 ppm provided almost the same behavior as the xanthan solution, whereas the presence of crude oil within the higher xanthan concentrations significantly stimulated the measured values of the complex modulus. For lower gum concentrations of up to 1000 ppm, oil concentration displayed no effect on both the storage and loss moduli, whereas for gum concentrations higher than 1000 ppm, both moduli increased gradually with crude oil concentration.
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Affiliation(s)
- Mamdouh Taha Ghannam
- Department of Chemical and Petroleum Engineering, Faculty of Engineering, United Arab Emirates University, Al-Ain 15551, United Arab Emirates
- Correspondence:
| | - Mohamed Y. E. Selim
- Department of Mechanical Engineering, Faculty of Engineering, United Arab Emirates University, Al-Ain 15551, United Arab Emirates
| | - Abdulrazag Y. Zekri
- Department of Chemical and Petroleum Engineering, Faculty of Engineering, United Arab Emirates University, Al-Ain 15551, United Arab Emirates
| | - Nabil Esmail
- Department of Mechanical Engineering, Concordia University, 1455 de Maisonneuve Boulevard W., Montreal, QC M3G 1M8, Canada
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2
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Characterization and purification of pentameric chimeric protein particles using asymmetric flow field-flow fractionation coupled with multiple detectors. Anal Bioanal Chem 2021; 413:3749-3761. [PMID: 33837800 PMCID: PMC8035888 DOI: 10.1007/s00216-021-03323-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/10/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
Porcine circovirus causes the post-weaning multi-systemic wasting syndrome. Despite the existence of commercial vaccines, the development of more effective and cheaper vaccines is expected. The usage of chimeric antigens allows serological differentiation between naturally infected and vaccinated animals. In this work, recombinant pentameric vaccination protein particles spontaneously assembled from identical subunits-chimeric fusion proteins derived from circovirus capsid antigen Cap and a multimerizing subunit of mouse polyomavirus capsid protein VP1 were purified and characterized using asymmetric flow field-flow fractionation (AF4) coupled with UV and MALS/DLS (multi-angle light scattering/dynamic light scattering) detectors. Various elution profiles were tested, including constant cross-flow and decreasing cross-flow (linearly and exponentially). The optimal sample retention, separation efficiency, and resolution were assessed by the comparison of the hydrodynamic radius (Rh) measured by online DLS with the Rh values calculated from the simplified retention equation according to the AF4 theory. The results show that the use of the combined elution profiles (exponential and constant cross-flow rates) reduces the time of the separation, prevents undesirable sample-membrane interaction, and yields better resolution. Besides, the results show no self-associations of the individual pentameric particles into larger clusters and no sample degradation during the AF4 separation. The Rg/Rh ratios for different fractions are in good correlation with morphological analyses performed by transmission electron microscopy (TEM). Additionally to the online analysis, the individual fractions were subjected to offline analysis, including batch DLS, TEM, and SDS-PAGE, followed by Western blot.
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3
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Bressel K, Müller W, Leser ME, Reich O, Hass R, Wooster TJ. Depletion-Induced Flocculation of Concentrated Emulsions Probed by Photon Density Wave Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3504-3513. [PMID: 32162925 DOI: 10.1021/acs.langmuir.9b03642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Stable, creaming-free oil in water emulsions with high volume fractions of oil (ϕ = 0.05-0.40, density matched to water) and polysorbate 80 as an emulsifier were characterized without dilution by Photon Density Wave spectroscopy measuring light absorption and scattering behavior, the latter serving as the basis for droplet size distribution analysis. The emulsion with ϕ = 0.10 was used to investigate flocculation processes induced by xanthan as a semi-flexible linear nonabsorbing polymer. Different time regimes in the development of the reduced scattering coefficient μs' could be identified. First, a rapid, temperature-dependent change in μs' during the depletion process was observed. Second, the further decrease of μs' follows a power law in analogy to a spinodal demixing behavior, as described by the Cahn-Hilliard theory.
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Affiliation(s)
- Katharina Bressel
- Physical Chemistry-InnoFSPEC, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany
| | - Wenke Müller
- Physical Chemistry-InnoFSPEC, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany
| | - Martin E Leser
- Institute of Material Science, Nestlé Research Center, Vers-chez-les-Blanc, 1000 Lausanne, Switzerland
| | - Oliver Reich
- Physical Chemistry-InnoFSPEC, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany
| | - Roland Hass
- Physical Chemistry-InnoFSPEC, University of Potsdam, Am Mühlenberg 3, 14476 Potsdam, Germany
| | - Tim J Wooster
- Institute of Material Science, Nestlé Research Center, Vers-chez-les-Blanc, 1000 Lausanne, Switzerland
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4
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Study on structure-function of starch by asymmetrical flow field-flow fractionation coupled with multiple detectors: A review. Carbohydr Polym 2019; 226:115330. [DOI: 10.1016/j.carbpol.2019.115330] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/05/2019] [Accepted: 09/11/2019] [Indexed: 12/29/2022]
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5
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Xiao X, Tan C, Sun X, Zhao Y, Zhang J, Zhu Y, Bai J, Dong Y, Zhou X. Effects of fermentation on structural characteristics and in vitro physiological activities of barley β-glucan. Carbohydr Polym 2019; 231:115685. [PMID: 31888856 DOI: 10.1016/j.carbpol.2019.115685] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 12/24/2022]
Abstract
The effects of fermentation by Lactobacillus plantarum dy-1 on the main structural changes of barley β-glucan and their in vitro activities were studied. Molecular characteristics, infrared spectroscopy, monosaccharide composition, methylation, 1D and 2D-NMR analyses and scanning electron microscopy revealed that both (raw barley β-glucan) RBG and fermented barley β-glucan (FBG) are polysaccharides predominanted by β-(1→3) and β-(1→4) linked glucose. However, different molecular weight (decreasing from 1.13×105 D to 6.35×104 D), the ratio of the β-(1→3) residues to the β-(1→4) residues (ranging from 1:1.98-1:2.50 to 1:1.8-1:2.24) and microstructure features (transforming from a rod-like to sheet-like structure) were observed. Bioassay results showed that FBG exhibited improved inhibitory activities of α-amylase, α-glucosidase and lipase, as well as the adsorption of cholesterol under acidic conditions compared to RBG. These results suggested that fermentation may enhance in vitro physiological activities of barley β-glucan, especially related to glucose and lipid metabolism.
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Affiliation(s)
- Xiang Xiao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Cui Tan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Xinjuan Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yansheng Zhao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Jiayan Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Ying Zhu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Juan Bai
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Ying Dong
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Xinghua Zhou
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China.
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Mrokowska MM, Krztoń-Maziopa A. Viscoelastic and shear-thinning effects of aqueous exopolymer solution on disk and sphere settling. Sci Rep 2019; 9:7897. [PMID: 31133719 PMCID: PMC6536512 DOI: 10.1038/s41598-019-44233-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 05/10/2019] [Indexed: 12/04/2022] Open
Abstract
In this study, xanthan gum is used as a model exopolymer to demonstrate potential effects of non-Newtonian properties of natural aquatic systems on settling dynamics of particles. Rheological measurements combined with settling experiments using visualization methods revealed that instantaneous velocity fluctuations and a flow pattern formed around a particle are the effects of solution viscoelasticity and shear-thinning properties and that the average settling velocity depends on the exopolymer concentration and particle size. Our study showed that in the considered conditions a disk-shaped particle settles preferably in vertical position with a negative wake behind. The understanding of these processes is essential in technology and engineering and is necessary to improve prediction accuracy of large-scale sedimentation processes and biogeochemical cycles in the ocean involving settling of minerals, marine snow, microplastics, and locomotion of microorganisms.
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Affiliation(s)
- Magdalena M Mrokowska
- Institute of Geophysics, Polish Academy of Sciences, Ks. Janusza 64, 01-452, Warsaw, Poland.
| | - Anna Krztoń-Maziopa
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego St. 3, 00-664, Warsaw, Poland
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Zielke C, Stradner A, Nilsson L. Characterization of cereal β-glucan extracts: Conformation and structural aspects. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.12.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Merino-González A, Kozina A. Influence of aggregation on characterization of dilute xanthan solutions. Int J Biol Macromol 2017; 105:834-842. [DOI: 10.1016/j.ijbiomac.2017.07.110] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/10/2017] [Accepted: 07/17/2017] [Indexed: 01/08/2023]
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9
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Perez-Rea D, Zielke C, Nilsson L. Co-elution effects can influence molar mass determination of large macromolecules with asymmetric flow field-flow fractionation coupled to multiangle light scattering. J Chromatogr A 2017; 1506:138-141. [DOI: 10.1016/j.chroma.2017.05.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/05/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
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10
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Philippova OE, Shibaev AV, Muravlev DA, Mityuk DY. Structure and Rheology of Solutions and Gels of Stiff Polyelectrolyte at High Salt Concentration. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01392] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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11
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Boye S, Ennen F, Scharfenberg L, Appelhans D, Nilsson L, Lederer A. From 1D Rods to 3D Networks: A Biohybrid Topological Diversity Investigated by Asymmetrical Flow Field-Flow Fractionation. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00824] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Susanne Boye
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Franka Ennen
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität
Dresden, 01062 Dresden, Germany
| | - Linda Scharfenberg
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität
Dresden, 01062 Dresden, Germany
| | - Dietmar Appelhans
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Lars Nilsson
- Food
Colloids Group and Lund Center for Field-Flow Fractionation, Department
of Food Technology, Engineering and Nutrition, Faculty of Engineering
LTH, Lund University, Lund, Sweden
| | - Albena Lederer
- Leibniz-Institut
für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität
Dresden, 01062 Dresden, Germany
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12
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Coviello T, Trotta AM, Marianecci C, Carafa M, Di Marzio L, Rinaldi F, Di Meo C, Alhaique F, Matricardi P. Gel-embedded niosomes: preparation, characterization and release studies of a new system for topical drug delivery. Colloids Surf B Biointerfaces 2014; 125:291-9. [PMID: 25524220 DOI: 10.1016/j.colsurfb.2014.10.060] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/10/2014] [Accepted: 10/19/2014] [Indexed: 10/24/2022]
Abstract
In the present paper physical gels, prepared with two polysaccharides, Xanthan and Locust Bean Gum, and loaded with non-ionic surfactant vesicles, are described. The vesicles, composed by Tween20 and cholesterol or by Tween85 and Span20, were loaded with Monoammonium glycyrrhizinate for release experiments. Size and zeta (ζ)-potential of the vesicles were evaluated and the new systems were characterized by rheological and dynamo-mechanical measurements. For an appropriate comparison, a Carbopol gel and a commercial gel for topical applications were also tested. The new formulations showed mechanical properties comparable with those of the commercial product indicating their suitability for topical applications. In vitro release experiments showed that the polysaccharide network protects the integrity of the vesicles and leads to their slow release without disruption of the aggregated structures. Furthermore, being the vesicles composed of molecules possessing enhancing properties, the permeation of the loaded drugs topically delivered can be improved. Thus, the new systems combine the advantages of matrices for a modified release (polymeric component) and those of an easier permeability across the skin (vesicle components). Finally, shelf live experiments indicated that the tested gel/vesicle formulations were stable over 1 year with no need of preservatives.
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Affiliation(s)
- T Coviello
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
| | - A M Trotta
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
| | - C Marianecci
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
| | - M Carafa
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy.
| | - L Di Marzio
- Department of Pharmacy, University of Chieti "G. D'Annunzio", Chieti, Italy
| | - F Rinaldi
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00185 Rome, Italy
| | - C Di Meo
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
| | - F Alhaique
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
| | - P Matricardi
- Department of Drug Chemistry and Technologies, "Sapienza", University of Rome, Rome, Italy
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13
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Reufer M, Machado AHE, Niederquell A, Bohnenblust K, Müller B, Völker AC, Kuentz M. Introducing diffusing wave spectroscopy as a process analytical tool for pharmaceutical emulsion manufacturing. J Pharm Sci 2014; 103:3902-3913. [PMID: 25302803 DOI: 10.1002/jps.24197] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/09/2014] [Accepted: 09/17/2014] [Indexed: 11/08/2022]
Abstract
Emulsions are widely used for pharmaceutical, food, and cosmetic applications. To guarantee that their critical quality attributes meet specifications, it is desirable to monitor the emulsion manufacturing process. However, finding of a suitable process analyzer has so far remained challenging. This article introduces diffusing wave spectroscopy (DWS) as an at-line technique to follow the manufacturing process of a model oil-in-water pharmaceutical emulsion containing xanthan gum. The DWS results were complemented with mechanical rheology, microscopy analysis, and stability tests. DWS is an advanced light scattering technique that assesses the microrheology and in general provides information on the dynamics and statics of dispersions. The obtained microrheology results showed good agreement with those obtained with bulk rheology. Although no notable changes in the rheological behavior of the model emulsions were observed during homogenization, the intensity correlation function provided qualitative information on the evolution of the emulsion dynamics. These data together with static measurements of the transport mean free path (l*) correlated very well with the changes in droplet size distribution occurring during the emulsion homogenization. This study shows that DWS is a promising process analytical technology tool for development and manufacturing of pharmaceutical emulsions.
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Affiliation(s)
- Mathias Reufer
- University of Applied Sciences and Arts Northwestern Switzerland, Institute of Pharma Technology, Muttenz CH-4132 Switzerland; LS Instruments, Fribourg CH-1700, Switzerland
| | - Alexandra H E Machado
- University of Applied Sciences and Arts Northwestern Switzerland, Institute of Pharma Technology, Muttenz CH-4132 Switzerland
| | - Andreas Niederquell
- University of Applied Sciences and Arts Northwestern Switzerland, Institute of Pharma Technology, Muttenz CH-4132 Switzerland
| | | | - Beat Müller
- Galderma Spirig, Spirig Pharma AG, Egerkingen CH-4622, Switzerland
| | | | - Martin Kuentz
- University of Applied Sciences and Arts Northwestern Switzerland, Institute of Pharma Technology, Muttenz CH-4132 Switzerland.
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14
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Oliveira PD, Michel RC, McBride AJA, Moreira AS, Lomba RFT, Vendruscolo CT. Concentration regimes of biopolymers xanthan, tara, and clairana, comparing dynamic light scattering and distribution of relaxation time. PLoS One 2013; 8:e62713. [PMID: 23671627 PMCID: PMC3646029 DOI: 10.1371/journal.pone.0062713] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/25/2013] [Indexed: 12/04/2022] Open
Abstract
The aim of this work was to evaluate the utilization of analysis of the distribution of relaxation time (DRT) using a dynamic light back-scattering technique as alternative method for the determination of the concentration regimes in aqueous solutions of biopolymers (xanthan, clairana and tara gums) by an analysis of the overlap (c*) and aggregation (c**) concentrations. The diffusion coefficients were obtained over a range of concentrations for each biopolymer using two methods. The first method analysed the behaviour of the diffusion coefficient as a function of the concentration of the gum solution. This method is based on the analysis of the diffusion coefficient versus the concentration curve. Using the slope of the curves, it was possible to determine the c* and c** for xanthan and tara gum. However, it was not possible to determine the concentration regimes for clairana using this method. The second method was based on an analysis of the DRTs, which showed different numbers of relaxation modes. It was observed that the concentrations at which the number of modes changed corresponded to the c* and c**. Thus, the DRT technique provided an alternative method for the determination of the critical concentrations of biopolymers.
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Affiliation(s)
- Patrícia D Oliveira
- Biotechnology, Technology Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil.
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15
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Separation and characterization of food macromolecules using field-flow fractionation: A review. Food Hydrocoll 2013. [DOI: 10.1016/j.foodhyd.2012.04.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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16
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Boye S, Appelhans D, Boyko V, Zschoche S, Komber H, Friedel P, Formanek P, Janke A, Voit BI, Lederer A. pH-Triggered Aggregate Shape of Different Generations Lysine-Dendronized Maleimide Copolymers with Maltose Shell. Biomacromolecules 2012; 13:4222-35. [DOI: 10.1021/bm301489s] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- S. Boye
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - D. Appelhans
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - V. Boyko
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - S. Zschoche
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - H. Komber
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - P. Friedel
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - P. Formanek
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - A. Janke
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
| | - B. I. Voit
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
- Technische Universität Dresden, D-01062 Dresden, Germany
| | - A. Lederer
- Leibniz-Institut für Polymerforschung Dresden, Hohe Str. 6, 01109
Dresden, Germany
- Technische Universität Dresden, D-01062 Dresden, Germany
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17
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He P, Geng L, Wang Z, Mao D, Wang J, Xu C. Fermentation optimization, characterization and bioactivity of exopolysaccharides from Funalia trogii. Carbohydr Polym 2012; 89:17-23. [PMID: 24750597 DOI: 10.1016/j.carbpol.2012.01.093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 01/28/2012] [Accepted: 01/30/2012] [Indexed: 12/24/2022]
Abstract
Optimization of culture conditions for exopolysaccharide (EPS) by Funalia trogii in submerged culture was investigated using one-factor-at-a-time method and uniform design (UD). Under the optimized conditions, the maximum concentration of EPS was 8.68 g/l. After EPS was deproteinized by Sevag method, two groups of EPSs (designated as Fr-I and Fr-II) were obtained from the culture filtrates by gel filtration chromatography on Sepharose CL-6B. Furthermore, EPSs were characterized by size exclusion chromatography (SEC) coupled with a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses of the Fr-I and Fr-II were determined to be 1.007 × 10(5) and 2.393 × 10(4)g/mol, respectively. The root mean square (RMS) radii for both peaks ranged from 9.7 to 10.8 nm with no clear trends. Pharmacology experiments indicated F. trogii EPS were useful to the therapy of free radical injury and cancer diseases.
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Affiliation(s)
- Peixin He
- College of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, PR China
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18
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Mei T, Xu X, Li B, Li J, Cui B, Zhou B, Ablaye W. Synergistic interaction of konjac glucomannan and gellan gum investigated by rheology and texture analysis. J Appl Polym Sci 2012. [DOI: 10.1002/app.35247] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Håkansson A, Ulmius M, Nilsson L. Asymmetrical flow field-flow fractionation enables the characterization of molecular and supramolecular properties of cereal β-glucan dispersions. Carbohydr Polym 2012; 87:518-523. [DOI: 10.1016/j.carbpol.2011.08.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 07/29/2011] [Accepted: 08/04/2011] [Indexed: 11/27/2022]
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20
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Penzkofer A, Stierl M, Hegemann P, Kateriya S. Thermal protein unfolding in photo-activated adenylate cyclase nano-clusters from the amoeboflagellate Naegleria gruberi NEG-M strain. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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21
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Fernandez C, Rojas CC, Nilsson L. Size, structure and scaling relationships in glycogen from various sources investigated with asymmetrical flow field-flow fractionation and 1H NMR. Int J Biol Macromol 2011; 49:458-65. [DOI: 10.1016/j.ijbiomac.2011.05.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 05/06/2011] [Accepted: 05/18/2011] [Indexed: 11/16/2022]
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23
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Sandolo C, Bulone D, Mangione MR, Margheritelli S, Di Meo C, Alhaique F, Matricardi P, Coviello T. Synergistic interaction of Locust Bean Gum and Xanthan investigated by rheology and light scattering. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2010.05.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Lee S, Kim ST, Pant BR, Kwen HD, Song HH, Lee SK, Nehete SV. Carboxymethylation of corn starch and characterization using asymmetrical flow field-flow fractionation coupled with multiangle light scattering. J Chromatogr A 2010; 1217:4623-8. [DOI: 10.1016/j.chroma.2010.04.082] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 03/22/2010] [Accepted: 04/29/2010] [Indexed: 11/25/2022]
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Order–Disorder Conformational Transition of Xanthan Gum. POLYSACCHARIDES 2010. [DOI: 10.1201/9781420030822.ch17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
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27
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Stojanović ZP, Jeremić K, Jovanović S, Nierling W, Lechner MD. Light Scattering and Viscosity Investigation of Dilute Aqueous Solutions of Carboxymethyl Starch. STARCH-STARKE 2009. [DOI: 10.1002/star.200800085] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Rojas CC, Wahlund KG, Bergenståhl B, Nilsson L. Macromolecular geometries determined with field-flow fractionation and their impact on the overlap concentration. Biomacromolecules 2008; 9:1684-90. [PMID: 18537296 DOI: 10.1021/bm800127n] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper we aim to understand the size/conformation relationship in waxy barley starch, a polydisperse and ultrahigh molar mass biomacromolecule. Characterizations are performed with asymmetrical flow field-flow fractionation (AsFlFFF). Furthermore, we study the effect of homogenization on the molar mass, rms radius (r rms) and hydrodynamic radius (r h). For the untreated sample, the macromolecules are elongated objects with low apparent density. As a result of homogenization, molar mass, and r rms decrease, while r h remains unaffected. The process also induces an increase, and scaling with size, of apparent density as well as changes in conformation, represented qualitatively by r rms/ r h. Finally, results from AsFlFFF are compared with viscosimetry and discussed in terms of concentration and close-packing in relation to macromolecular shape and conformation. Hence, the results show that AsFlFFF and our novel methodology enable the determination of several physical properties with high relevance for the solution behavior of polydisperse macromolecules.
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Affiliation(s)
- Cinthia Carola Rojas
- Division of Food Technology, Faculty of Engineering LTH, Lund University, Post Office Box 124, S-221 00 Lund, Sweden
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Higiro J, Herald T, Alavi S, Bean S. Rheological study of xanthan and locust bean gum interaction in dilute solution: Effect of salt. Food Res Int 2007. [DOI: 10.1016/j.foodres.2006.02.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Nilsson L, Leeman M, Wahlund KG, Bergenståhl B. Mechanical degradation and changes in conformation of hydrophobically modified starch. Biomacromolecules 2007; 7:2671-9. [PMID: 16961331 DOI: 10.1021/bm060367h] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper, we study the mechanical degradation and changes in conformation of a branched ultrahigh molar mass biomacromolecule, hydrophobically modified starch, as caused by high-pressure homogenization. The characterization was performed with asymmetrical flow field-flow fractionation (AsFlFFF) with multiangle light scattering (MALS) and refractive index detection. The starch which had been chemically modified with octenyl succinate anhydride (OSA) proved to be very large and polydisperse. Upon high-pressure homogenization, the molar mass and rms radius (r(rms)) decreased, and the extent of these changes was related to the turbulent flow conditions during homogenization. The treatment also induced an increase and scaling with size in the apparent density of the macromolecules. To further study the changes in conformation, it was necessary to calculate the hydrodynamic radii (r(h)). This can be determined numerically from the elution times in the analysis and the flow conditions in the AsFlFFF channel. The results showed that the treatment can cause a dramatic decrease in the quotient between r(rms) and r(h), suggesting major conformational changes. These results together could be interpreted as degradation and "crumpling" of the macromolecule, which would give a decrease in r(rms) and an increase in apparent density, together with a "fraying" of more outer parts of the macromolecule, which could give rise to the increase in r(h).
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Affiliation(s)
- Lars Nilsson
- Division of Food Technology and Division of Technical Analytical Chemistry, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, S-221 00 Lund, Sweden.
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31
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Patel TR, Picout DR, Ross-Murphy SB, Harding SE. Pressure Cell Assisted Solution Characterization of Galactomannans. 3. Application of Analytical Ultracentrifugation Techniques. Biomacromolecules 2006; 7:3513-20. [PMID: 17154482 DOI: 10.1021/bm060674n] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pressure heating cell approach previously applied to galactomannans in two earlier studies is now used to prepare samples for characterization using the analytical ultracentrifuge. Sedimentation velocity data were obtained for both guar gum and locust bean gum samples. These were compared to our earlier light scattering and intrinsic viscosity measurements on samples prepared using identical temperature and pressure profiles. A number of methods were then employed to obtain chain persistence lengths, including the Hearst-Stockmayer and Bohdanecky wormlike chain approaches. These results were compared to earlier results obtained using methods appropriate for excluded volume coil and rodlike chains, respectively.
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Affiliation(s)
- Trushar R Patel
- NCMH Laboratory, School of Biosciences, University of Nottingham, Sutton, Bonington LE12 5RD, United Kingdom
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Sletmoen M, Geissler E, Stokke BT. Determination of Molecular Parameters of Linear and Circular Scleroglucan Coexisting in Ternary Mixtures Using Light Scattering. Biomacromolecules 2006; 7:858-65. [PMID: 16529424 DOI: 10.1021/bm050990m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A combination of static and dynamic light scattering (SLS and DLS) is applied here to determine molecular parameters for coexisting linear and circular scleroglucan polymers of similar molecular weights, dissolved in water, that is, forming a ternary system. The weight-average molecular weights, M(w), were determined to be 3.2 x 10(5) and 3.9 x 10(5) g/mol for the circular and linear molecules, respectively, whereas the z-average radius of gyration, R(g), was found to be equal to 41 nm for the circular molecules and 136 nm for the linear ones. These values are within a physically reasonable range in view of the heterogeneity of the samples. This study confirms that decomposition of total scattering intensities deduced from the dynamic properties can be used to determine molecular parameters of populations of molecules of equal M(w) but different morphologies present in ternary mixtures.
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Affiliation(s)
- Marit Sletmoen
- Biophysics and Medical Technology, Department of Physics, The Norwegian University of Science and Technology, NTNU, NO-7491 Trondheim, Norway
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Abstract
Successive changes of solvent conditions can be used to dissociate and reassociate the triple-helical structure of (1,3)-beta-D-glucans. Ultramicroscopic techniques have revealed a blend of circular and other structures following renaturation. When this solvent exchange process is carried out in the presence of certain polynucleotides, the process creates a novel macromolecular complex. Here, we use size exclusion chromatography (SEC) to study such (1,3)-beta-D-glucan-polynucleotide complexes. Online multi-angle laser-light scattering (MALLS) and refractive index (RI) detectors allowed determination of molecular weight and radius of gyration of the molecules. An ultraviolet (UV) detector allowed specific detection of the polynucleotide. The poly-cytidylic acid (poly C) shifted to coelution with the linear fraction of the scleroglucan following the renaturation of poly C-scleroglucan blends, indicating that poly C is incorporated in linear, but not in circular, structures of scleroglucan. This conclusion was consistent with AFM topographs that revealed a decreased fraction of circular structures upon addition of poly C during the renaturation process. The combined information about radius of gyration (R(g)) and molecular weight (M(w)) allowed us to conclude that the poly C-scleroglucan complexes are more dense and have a higher persistence length than linear scleroglucan triple helixes. The experimentally determined mass per unit length was used as a basis for elucidating possible molecular arrangements within the poly C-scleroglucan complex.
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Affiliation(s)
- Marit Sletmoen
- Biophysics and Medical Technology, Department of Physics, The Norwegian University of Science and Technology, NTNU, NO-7491 Trondheim, Norway
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Bylaite E, Adler-Nissen J, Meyer AS. Effect of xanthan on flavor release from thickened viscous food model systems. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:3577-83. [PMID: 15853404 DOI: 10.1021/jf048111v] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The influence of xanthan concentration (0, 0.02, 0.1, 0.4, and 0.8% w/w) and bulk viscosity on the release of 20 aroma compounds of different chemical classes (5 aldehydes, 4 esters, 5 ketones, 3 alcohols, and 3 terpenes) was evaluated in xanthan-thickened food model systems having different viscosities. Interactions between flavor compounds and xanthan were assessed by measuring air-liquid partition coefficients, K, of aroma compounds in pure water and in the xanthan solutions by static headspace gas chromatography. Mass transfer of aroma compounds was estimated by dynamic headspace gas chromatography. Notably, limonene and some of the esters and aldehydes exhibited decreased K values in the presence of xanthan, indicating that the release of these volatile aroma compounds was reduced due to interaction with the xanthan matrix. The degree of interaction depended on the physicochemical characteristics of the aroma compounds. A similar tendency was observed at nonequilibrium with the decreases in release rates being most pronounced for limonene, followed by the esters and aldehydes, with no effect for ketones and an apparent "salting out" effect for alcohols. The reduction in flavor release by xanthan was thus dependent on the physicochemical properties of the aroma compounds and was apparently a result of the aroma-xanthan interactions and not influenced by the viscosity of the system itself.
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Affiliation(s)
- Egle Bylaite
- Food Biotechnology and Engineering Group, BioCentrum-DTU, Soeltofts Plads, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
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Ren Y, Picout DR, Ellis PR, Ross-Murphy SB, Reid JSG. A novel xyloglucan from seeds of Afzelia africana Se. Pers.—extraction, characterization, and conformational properties. Carbohydr Res 2005; 340:997-1005. [PMID: 15780264 DOI: 10.1016/j.carres.2005.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Accepted: 01/12/2005] [Indexed: 11/22/2022]
Abstract
This paper is the first multi-scale characterization of the xyloglucan extracted from seeds of the African tree Afzelia africana Se. Pers. It describes the extraction and characterization of this polysaccharide in terms of both primary monosaccharide and oligosaccharide composition. It also includes a study of the seed morphology. Morphological characterization includes optical, transmission, and scanning electron microscopy. The polysaccharide exists in thickened cell walls of the cotyledonary cells, and the extracted xyloglucan is structurally quite similar to those from tamarind seed and detarium. Nevertheless there are some subtle differences in the fine structure, particularly in the oligomeric xyloglucan composition. The chain flexibility of the polysaccharide is also discussed in the light of our recent measurements reported elsewhere [Biomacromolecules2004, 5, 2384-2391].
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Affiliation(s)
- Yilong Ren
- Department of Life Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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Yoshiba K, Teramoto A, Nakamura N, Shikata T, Miyazaki Y, Sorai M, Hayashi Y, Miura N. Water Structures of Differing Order and Mobility in Aqueous Solutions of Schizophyllan, a Triple-Helical Polysaccharide as Revealed by Dielectric Dispersion Measurements. Biomacromolecules 2004; 5:2137-46. [PMID: 15530027 DOI: 10.1021/bm040036+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dielectric dispersion measurements were made on aqueous solutions of a triple-helical polysaccharide schizophyllan over a wide concentration range 10-50 wt % at -45 to +30 degrees C. In the solution state, three different water structures with the different relaxation times tau were found, namely, bound water (taul), structured water (taus), and loosely structured water (tauls) in addition to free water (tauP). Structured water is less mobile and loosely structured water is nearly as mobile as free water, but bound water with taul is much less mobile, thus taul >> taus >> tauls greater, similar tauP. The order-disorder transition accompanies the conversion between structured water and loosely structured water. However, the species with taus remains even in the disordered state and constitutes part of bound water in the entire temperature range. In the frozen state, in addition to bulk water formed by partial melting, two mobile species existed, which were assigned to liquidlike bound water and found to be a continuation of bound water in the solution state. These relaxation time data are discussed in connection with the entropy levels of the four structures deduced from heat capacity data (cf. Yoshiba, K.; et al. Biomacromolecules 2003, 4, 1348-1356).
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Affiliation(s)
- Kazuto Yoshiba
- Research Organization of Science and Engineering and Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Nojihigashi 1-1-1, Kusatsu, Siga 525-8577, Japan.
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39
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Savin G, Burchard W. Uncommon Solution Behavior of Poly(N-vinylimidazole). Angular Dependence of Scattered Light from Aggregates in Ethanol. Macromolecules 2004. [DOI: 10.1021/ma0353639] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriela Savin
- Institute of Macromolecular Chemistry, Albert-Ludwig-University Freiburg, 70104 Freiburg, Germany, and “Transilvania” University of Brasov, 2200 Brasov, Romania
| | - Walther Burchard
- Institute of Macromolecular Chemistry, Albert-Ludwig-University Freiburg, 70104 Freiburg, Germany, and “Transilvania” University of Brasov, 2200 Brasov, Romania
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40
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Koenderink GH, Sacanna S, Aarts DGAL, Philipse AP. Rotational and translational diffusion of fluorocarbon tracer spheres in semidilute xanthan solutions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:021804. [PMID: 14995480 DOI: 10.1103/physreve.69.021804] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Indexed: 05/24/2023]
Abstract
We report an experimental study of rotational and translational diffusion and sedimentation of colloidal tracer spheres in semidilute solutions of the nonadsorbing semiflexible polymer xanthan. The tracers are optically anisotropic, permitting depolarized dynamic light scattering measurements without interference from the polymer background. The xanthan solutions behave rheologically like model semidilute polymeric solutions with long-lived entanglements. On the time scale of tracer motion the xanthan solutions are predominantly elastic. The generalized Stokes-Einstein relation describing the polymer solution as a continuous viscous fluid therefore severely overestimates the tracer hindrance. Instead, effective medium theory, describing the polymer solution as a homogeneous Brinkman fluid with a hydrodynamic screening length equal to the concentration-dependent static correlation length, is in excellent agreement with the tracer sedimentation and rotational diffusion coefficients. Rotational diffusion, however, is at the same time in good agreement with a simple model of a rotating sphere in a concentric spherical depletion cavity. Translational diffusion is faster than predicted for a Brinkman fluid, likely due to polymer depletion.
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Affiliation(s)
- Gijsberta H Koenderink
- Physics of Complex Systems, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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41
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Stokke BT, Smidsrød O, Elgsaeter A. Electron microscopy of native xanthan and xanthan exposed to low ionic strength. Biopolymers 2004. [DOI: 10.1002/bip.360280207] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Yoshiba K, Teramoto A, Nakamura N, Kikuchi K, Miyazaki Y, Sorai M. Static water structure detected by heat capacity measurements on aqueous solutions of a triple-helical polysaccharide schizophyllan. Biomacromolecules 2003; 4:1348-56. [PMID: 12959605 DOI: 10.1021/bm0300251] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Heat capacity measurements were made on aqueous solutions of a triple-helical polysaccharide schizophyllan by precision adiabatic calorimetry over a wide range of concentrations 30.45-90.93 wt % at temperatures between 5 and 315 K. The heat capacity curves obtained were divided into four groups depending on the weight fraction of schizophyllan w regions I-IV. In region I, triple-helices with the sheath of bound water, structured water, and loosely structured water forming layers around the helix core are embedded in free water. In region II, there is no free water, and loosely structured water decreases until it vanishes, but structured water stays constant with increasing w. In region III, bound water remains unaffected, but structured water decreases with increasing w by overlapping each other. Finally, in region IV, only schizophyllan and bound water exist, the latter decreasing upon increasing w. The maximum thickness of each layer is 0.18(3) nm for bound water, 0.13(4) nm for structured water, and 0.23(6) nm for loosely structured water, and these layers of water are at the enthalpy levels of 53%, 93.7%, and nearly 100%, respectively, between ice (0%) and free water (100%).
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Affiliation(s)
- Kazuto Yoshiba
- Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Nojihigashi 1-1-1, Kusatsu, Siga 525-8577, Japan
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43
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Effect of sucrose on molecular and interaction parameters of sodium caseinate in aqueous solution: relationship to protein gelation. Colloids Surf B Biointerfaces 2003. [DOI: 10.1016/s0927-7765(03)00041-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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44
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Koenderink GH, Aarts DGAL, de Villeneuve VWA, Philipse AP, Tuinier R, Lekkerkerker HNW. Morphology and kinetics of phase separating transparent xanthan-colloid mixtures. Biomacromolecules 2003; 4:129-36. [PMID: 12523857 DOI: 10.1021/bm025633f] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a study on the morphology and kinetics of depletion-induced phase separation in aqueous xanthan-colloid mixtures with light microscopy and small angle light scattering (SALS), using fluorinated colloids with a refractive index close to that of water to prevent complications of multiple scattering. Microscopy with the direction of observation perpendicular to gravity enabled us to observe the development of the microstructure during the entire phase separation process including the formation of a macroscopic interface. Bicontinuous structures typical of a spinodal decomposition mechanism were observed at early times. These structures coarsened in time until hydrodynamic flow resulted in lane formation. Close to the binodal, a nucleation-and-growth mechanism was observed with formation of droplets. The coarsening kinetics were studied in more detail with SALS and turbidity measurements. Above polysaccharide concentrations at which entanglements become dominant, a slower coarsening and macroscopic phase separation were found because of the high continuous phase viscosity.
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Affiliation(s)
- Gijsberta H Koenderink
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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Lee HC, Brant DA. Rheology of concentrated isotropic and anisotropic xanthan solutions: 3. Temperature dependence. Biomacromolecules 2002; 3:742-53. [PMID: 12099818 DOI: 10.1021/bm025510v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oscillatory rheology of one rodlike and one semiflexible xanthan sample has been investigated as a function of temperature in the range of xanthan concentrations where the polymer forms a lyotropic liquid crystalline phase in aqueous NaCl solutions. Readily observed changes in the rheological observables at temperatures corresponding to phase boundaries permit construction of the biphasic chimney region of the temperature-composition phase diagram. The chimney region leans toward larger values of the polymer concentration with increasing temperature, presumably as a consequence of a reduction in the effective axial ratio of the helical polymer with increasing temperature. The results permit construction of plots of the rheological observables as a function of polymer concentration at temperatures T in the range 20 <or= T <or= 90 degrees C. Characteristic features of these curves observed at room temperature are preserved at higher temperatures, provided the xanthan double helix remains intact. The temperature dependence of the viscosity of isotropic xanthan solutions can be described with the Arrhenius law. For anisotropic solutions the viscosity increases with T at the higher end of the experimental temperature range, presumably because higher temperatures reduce the order parameter of the liquid crystalline phase with a concomitant increase in viscosity. At low NaCl concentration, and low polymer concentration, the xanthan helix order-disorder transition occurs at temperatures T(m) below 90 degrees C. At temperatures above T(m) the rheological observables reveal the onset of network formation involving xanthan chains released from the ordered helical structure. When these systems are cooled back below T(m), extensive network formation develops with large increases in viscosity and in the storage and loss moduli.
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Affiliation(s)
- Hu-Cheng Lee
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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Esquenet C, Buhler E. Aggregation Behavior in Semidilute Rigid and Semirigid Polysaccharide Solutions. Macromolecules 2002. [DOI: 10.1021/ma012047q] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Catherine Esquenet
- Centre de Recherches sur les Macromolécules Végétales, UPR No. 5301, CNRS, affiliated with Joseph Fourier University, BP53, 38041 Grenoble Cedex 9, France
| | - Eric Buhler
- Centre de Recherches sur les Macromolécules Végétales, UPR No. 5301, CNRS, affiliated with Joseph Fourier University, BP53, 38041 Grenoble Cedex 9, France
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Dickinson E, Semenova MG, Belyakova LE, Antipova AS, Il'in MM, Tsapkina EN, Ritzoulis C. Analysis of Light Scattering Data on the Calcium Ion Sensitivity of Caseinate Solution Thermodynamics: Relationship to Emulsion Flocculation. J Colloid Interface Sci 2001; 239:87-97. [PMID: 11397052 DOI: 10.1006/jcis.2001.7480] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We describe the quantitative interrelation between the thermodynamic parameters of caseinate submicelles in the presence of calcium ions (0-14 mM) in aqueous medium and the capacity of the protein to induce depletion flocculation in oil-in-water emulsions at pH 7.0 and ionic strength 0.05 mol dm(-3). Measurements have been made by static and dynamic multiangle laser light scattering of the weight-average molecular weight, the radius of gyration, the hydrodynamic radius, and the second virial coefficient of caseinate submicelles in aqueous solution. Successive thermodynamic approximations with and without consideration of correlations between caseinate submicelles have been used to calculate the osmotic pressure in caseinate aqueous solutions and the free energy of the depletion interaction between droplets in oil-in-water emulsions stabilized by caseinate. Numerical results from both thermodynamic approximations are in reasonably good agreement with experiment, predicting a pronounced decrease in the strength of the depletion attraction at concentrations of Ca(2+) in the range 4-8 mM (with a minimum value at 8 mM). This correlates well with the great enhancement of stability of these emulsions with respect to flocculation in comparison with systems having no added ionic calcium and emulsions with lower (2 mM) or higher (10 mM) Ca(2+) contents. Nevertheless, the allowance for interactive correlations between caseinate submicelles seems to lead to a better prediction of emulsion flocculation on a qualitative level over the whole range of Ca(2+) concentrations studied (2-14 mM). The calculated pronounced decrease in depletion interaction strength is attributable to marked changes in weight-average molecular weight and mean size of aggregates, and to more positive values of the second virial coefficient of caseinate submicelles with increasing Ca(2+) content. Finally, we discuss the part played by the electrical charge on the protein in determining the overall strength of the flocculation-inducing attractive interactions between droplets. Copyright 2001 Academic Press.
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Affiliation(s)
- Eric Dickinson
- Procter Department of Food Science, University of Leeds, Leeds, LS2 9JT, United Kingdom
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48
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Saalwächter K, Burchard W. Cellulose in New Metal-Complexing Solvents. 2. Semidilute Behavior in Cd-tren. Macromolecules 2001. [DOI: 10.1021/ma0016073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kay Saalwächter
- Institute of Macromolecular Chemistry, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
| | - Walther Burchard
- Institute of Macromolecular Chemistry, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
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49
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Ioan CE, Aberle T, Burchard W. Structure Properties of Dextran. 2. Dilute Solution†. Macromolecules 2000. [DOI: 10.1021/ma000282n] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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50
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