M. Rampp et al., c,T-dependence of the viscosity and the self-diffusion coefficients in some aqueous carbohydrate solutions, CARBOHY RES, 328(4), 2000, pp. 561-572
Self-diffusion coefficients for both components are reported for the highly
concentrated aqueous solutions of some disaccharides and fructose as a fun
ction of temperature and concentration. These data are complemented by visc
osity measurements. The disaccharides studied are sucrose, alpha,alpha-treh
alose, allosucrose, and leucrose. Up to a sugar concentration of approximat
e to 30% w/w the viscosity and the self diffusion coefficients of the four
disaccharides are identical within experimental error for a given concentra
tion and temperature. Water diffusion shows no differences in the four syst
ems studied under these conditions. At higher concentrations significant di
fferences are observed that become more pronounced with increasing temperat
ure. Analysis of the data by the VTF equation yields the result that at a g
iven concentration the self diffusion coefficients of the sugar D-c and the
viscosity eta are described by identical ideal glass transition temperatur
es T-0, while the diffusion of the water D-W molecule decouples from these
properties. T-0(W) is always lower than T-0(c,eta). (C) 2000 Published by E
lsevier Science Ltd. All rights reserved.