Rheology and microstructure of dispersions and solutions of the microbial polysaccharide from Xanthomonas campestris (xanthan gum)

Morris, Victor J.; Franklin, David S.; I'Anson, K.J.

doi:10.1016/0008-6215(83)84002-6

Cited by 48 publications

(14 citation statements)

References 32 publications

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“…Nevertheless the optical rotation (and n.m.r.) data for both native xanthan and the Na+ form demonstrate that the ordered helical structure is retained after heat treatment for both ' aqueous' and urea-treated samples.l19 21 The evidence thus suggests that the 'slow' mode in the QELS spectrum and the predominantly elastic mechanical response (to o < 0.1 rad s-l) result from intermolecular association of the polymer chains. The irreproducible and irreversible results obtained, for example, on xanthan aqueous 'dispersions' without heat treatment in both QELS and mechanical measurements strongly imply that such ' dispersions' involve supramolecular aggregates which only slowly ' dissolve '.…”

Section: Discussionmentioning

confidence: 98%

Molecular viscoelasticity of xanthan polysaccharide

Ross‐Murphy¹,

Morris²,

Morris³

1983

Faraday Symp. Chem. Soc.

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166

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Previous studies of xanthan polysaccharide using molecular probes of local chain geometry such as optical rotation and n.m.r. have demonstrated a cooperative disorder-order transition in aqueous solution on cooling or on addition of salt. In the present work we have investigated chain geometry of the ordered species at a 'macromolecular level' using quasi-elastic light scattering, transient electric birefringence and elongational flow birefringence, and have used viscoelastic measurements to probe the ' supramolecular' organisation responsible for the ' weak-gel ' properties of xanthan solutions.Solution viscoelasticity at fixed xanthan concentration was drastically modified by changing the counterion to the polyelectrolyte and by treatment with urea, although in all cases the local ordered structure was unaffected. ' Macromolecular' studies under conditions which minimise intermolecular interactions (Na+ salt form in the presence of urea) and at substantially lower concentrations indicate a persistence length comparable to that of other highly persistent biopolymers, such as double helical DNA and the triple helical polysaccharide schizophyllan.We conclude that in aqueous solution xanthan may be regarded as a highly extended worm-like chain interacting by non-covalent association to develop a weak-gel network, which is readily reversible under shear.

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Section: Discussionmentioning

confidence: 98%

Molecular viscoelasticity of xanthan polysaccharide

Ross‐Murphy¹,

Morris²,

Morris³

1983

Faraday Symp. Chem. Soc.

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166

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“…THE STRUCTURAL and rheological properties of xanthan gum dispersions have been reported by Rocks (1971), Rao andKenny (1975), andTanaka andFukuda ( 1976). In recent years many other researchers have also investigated xanthan gum solution properties (Sanford et al, 1977;Whitcomb et al, 1977;Chang and Ollis, 1982;Narayan and Ramasubramanian, 1982;Morris et al, 1983;Southwick et al, 1983;Zatz and Knapp, 1984).…”

Section: Introductionmentioning

confidence: 99%

Concentration and Temperature Dependence of Flow Behavior of Xanthan Gum Dispersions

Speers

Tung

1986

Journal of Food Science

103

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Apparent viscosities of xanthan gum dispersions over shear rates of 0.5-3000~s' were studied at concentrations of 0.05-I .OO% (w/w) and temperatures of 5-45"C. All dispersions were shear rate thinning nonNewtonian fluids described accurately by the power-law model. The logarithm of viscosity varied with the logarithm of concentration and the reciprocal of absolute temperature. A combined model was derived to describe the variation of viscosity with shear rate, concentration and temperature for aqueous dispersions of xanthan gum. D

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“…The xanthan solution showed shear thinning property at a shear rate below 16.8 s −1 , at which its apparent viscosity was determined. This macromolecule is reported to be incompletely solvated in water with a weak gel-like structure (Morris et al, 1983). However, the apparent viscosity at a shear rate of 16.…”

Section: Resultsmentioning

confidence: 99%

Analysis of Apparent Viscosity of Aqueous Macromolecule Solutions Containing Sucrose

Sato

Miyawaki

2012

FSTR

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The apparent viscosity (η a H ) of aqueous macromolecule solutions with and without sucrose was measured. In addition, the apparent reduced viscosity (η and its relationship with [η], the apparent viscosity behavior of the macromolecule solutions tested was classified into three groups. In Group A which consists of PEG35000 and DexT40, the macromolecules are diluted enough such that intermolecular interactions are very weak. In Group B which consists of pectins and alginate, the macromolecules are in contact with one another such that inter-macromolecular interactions become stronger and the addition of sucrose affects the macromolecular interactions. In Group C which consists of xanthan, macromolecular chains are physically entangled with partial aggregations such that inter-macromolecular interactions are very strong, but the addition of sucrose has almost no effect on the interaction.

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Rheology and microstructure of dispersions and solutions of the microbial polysaccharide from Xanthomonas campestris (xanthan gum)

Cited by 48 publications

References 32 publications

Molecular viscoelasticity of xanthan polysaccharide

Molecular viscoelasticity of xanthan polysaccharide

Concentration and Temperature Dependence of Flow Behavior of Xanthan Gum Dispersions

Analysis of Apparent Viscosity of Aqueous Macromolecule Solutions Containing Sucrose

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