Sugar aqueous solutions, viscosity temperature

There are similar temperature and concentration influences on the viscosity of aqueous solutions of many sugars and sugar alcohols. As an example, Fig. 19.2 shows viscosity curves for sucrose as a function of both temperature and concentration. 

Two groups have used physical measurements e.g. density, viscosity, refractive index, and optical rotation) to determine the compositions of solutions of water-sucrose-D-glucose (or invert sugar) at various temperatures. The diffusion coefficient for self-diffusion of D-fructose in an aqueous system has been measured over a range of concentrations and temperatures. The yields of trapped electrons and radicals have been determined following y-irradiation of frozen aqueous solutions of sugars. ... 

Two methods are employed industrially to produce crystalline fructose, aqueous crystallization and alcoholic crystallization. Yields of fructose crystallized from water syrups are only of the order of 50%, due to the very high water solubility of the sugar, while the high viscosity of the concentrated solution results in long crystallization times, typically 50 hours or more (2). The second process requires the addition of lower alcohols (eg. ethanol) to a concentrated fructose syrup, generally 90% total solids or more, at temperatures of 50 C to 80""c and then cooling to cause crystallization. Fructose yields are from 70 to 80% and the total time involved is 8 to 12 hours (3). However, large quantities of... 

Fig. 11 Standard representation of the temperature dependence of viscosity of aqueous sugar solutions of different concentrations as well as their reference-invariant approximation using ip = -0.500 (solid curve). For key parameters a(x)...

Fig. 11 shows the reference-invariant representation of the temperature dependence of viscosity of aqueous sugar solutions of different concentration (x - mass portion of cane sugar). To obtain this correlation, p and (T - T0) had to be transformed by the transformation or key parameters a = 1/yo [K] and b [Pa s] as w = p/b and u = (T-T0)/a, whereby a and b are functions ofx, see auxiliary diagram in Fig. 11. The reference temperature is T0 = 20 °C.

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