Polysaccharides solutions

Characteristics due to chemical functionalities (e.g., carboxyl groups) of sample components that control solubility of the sample in aqueous media, viscosity of carbohydrate/polysaccharide solutions, and stability of obtained solutions. 

Winzor and coworkers have employed measurements of the Donnan distribution of small ions in dialysis equilibrium [14] to reinforce earlier evidence of charge-screening effects in polysaccharide anions [164,165]. These researchers used the absorption optical system of a Beckman XL-1 ultracentrifuge to monitor the distribution of ions in polysaccharide solutions... 

The specific viscosity Tj for different values of the concentration (C) of the analyzed polysaccharide solutions in 0.15 M NaCl was determined by means of a capillary viscometer (Ubbelode) at 25°C. 

Chauveteau, G. Kohler, N. "Influence of Microgels in Xanthan Polysaccharide Solutions on Their Flow Through Various Porous Media," SPE paper 9295, 1980 SPE Annual Technical Conference and Exhibition, Dallas, September 21-24. 

Glass, J.E. Soules, D.A. Ahmed, H. "Viscosity Stability of Aqueous Polysaccharide Solutions", SPE paper 11691, 1983 California Regional Meeting, Ventura, March 23-25. 

Some early studies on the diffusion of globular proteins in polysaccharide solutions 37,38) (SyStem A) revealed that the movement of the proteins is markedly retarded. The diffusive retardation of the globular proteins may be described by the empirical relationship... 

Protein Concentration. For a given type of protein, a critical concentration Is required for the formation of a gel and the type of gel varies with the protein concentration. For example, gelatin and polysaccharide solutions will form gels at relatively low concentrations of the gelling material. Considerably higher protein concentration Is usually required for the gelation of globular proteins. 

For conformational transitions to occur in polysaccharide solutions and for the biological associations of polysaccharides to be readily and conveniently temperature-reversible226 is unusual. Hence, it is fortunate that systems have been discovered in which both of these types of behavior are modelled and can be observed together. It is to be expected that such systems will prove useful in the further development of the theory of conformation in respect of biological function. 

Hoyt JW (1985) Drag reduction in polysaccharide solutions Trends in Biotechnol 3 17... 

These structures and conformations of polysaccharide molecules and their intermolecular associations give polysaccharide solutions, polysaccharide dispersions, and polysaccharide gels their special properties in biologic systems and in industrial usage. The ease with which polysaccharides dissolve is related to their conformation and structure in many the same ways as is their solution behavior. 

For simple fluids, also known as Newtonian fluids, it is easy to predict the ease with which they will be poured, pumped, or mixed in either an industrial or end-use situation. This is because the shear viscosity or resistance to flow is a constant at any given temperature and pressure. The fluids that fall into this category are few and far between, because they are of necessity simple in structure. Examples are water, oils, and sugar solutions (e.g., honey unit hi.3), which have no dispersed phases and no molecular interactions. All other fluids are by definition non-Newtonian, so the viscosity is a variable, not a constant. Non-Newtonian fluids are of great interest as they encompass almost all fluids of industrial value. In the food industry, even natural products such as milk or polysaccharide solutions are non-Newtonian. 

Mindful of the energy requirement for dispersion of a polysaccharide solute in water, syneresis is the slow, spontaneous separation of liquid from a gel, as the solid phase attempts to return to its energy ground state. This phenomenon is a quality defect, because it foreshadows solute sedimentation. 

For polysaccharide dispersions, SV is exceedingly small relative to Vi. Equations (3.11) and (3.12) are mathematical propositions that the exchangeable energy stored in a dispersed polysaccharide solute is equal to the energy absorbed from an external source and any increase in surface area of the solute is consequently a repository of +A . Conversely, aggregation and desorption correspond to a loss of energy, felt as heat in the latter occurrence ( —A ) when a dry polyaccharide powder is wetted (positive adsorption). 

Morris, E. R., Cutler, A. N., Ross-Murphy, S. B., Rees, D. A., and Price, J. (1981). Concentration and shear rate dependence of viscosity in random coil polysaccharide solutions. Carbohydr. Polym. 1 5-21. 

The binodal branches do not coincide with the phase diagram axes. This means that the biopolymers are limitedly cosoluble. For instance, on mixing a protein solution A and a polysaccharide solution B a mixture of composition C can be obtained. This mixed solution spontaneously breaks down into two liquid phases, phase D and phase E. Phase D is rich in protein and E is rich in polysaccharide. These two liquid phases form a water-in-water (WIW) emulsion. Hie phase volume ratio is estimated by the inverse lever rule. The phase D/phase E volume ratio equals the ratio of the tieline segments EC/CD. Point F represents the phase separation threshold, that is, the minimal critical concentration of biopolymers required for phase separation to occur. 

Wang, S., van Dijk, J. A. P. R, Odijk, T., and Smit, J. A. M. 2001. Depletion induced demixing in aqueous protein-polysaccharide solutions. Biomacromolecules 2 1080-1088. 

Morris, E. R., Richardson, R. K., and Taylor, L. J. 1984. Correlation of the perceived texture of random coil polysaccharide solutions with objective parameters. Carbohydr. polym. 4 175-191. 

Chromatography. Filtered polysaccharide solutions were analyzed using an SEC system consisting of an automatic sampler (Waters WISP, Waters, Milford, MA) with a high-performance liquid chromatography pump (Waters model 590), pulse dampener (Viscotek, Houston, TX), viscometer... 

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