Temperature dependence of the viscosity of sugar and maltodextrin solutions in coexistence with ice

Abstract

The viscosities of glucose, sucrose, and maltodextrin solutions coexisting with ice were measured by rotational viscometry. Samples were prepared by forming a shell of pure ice in a stainless steel tube immersed in a cooling bath, then introducing aqueous solutions at concentrations corresponding to the ice-melt equilibrium temperature. Temperature dependence of viscosity was analysed in terms of Arrhenius, VTF, WLF, and power-law models. Two glass transition reference temperatures were used with the WLF and power-law models: (1) Tg associated with the transition from liquid to glass and (2) Tg′ associated with the transition to glass from a maximally freeze-concentrated solution. Plots of Logη vs I/T were fairly linear for each solution, but each displayed a unique slope with EA ranging from 168 kJ/K mol to 464 kJ/K mol. WLF and power law models gave a linear fit to all solutions when Tg was chosen as the reference temperature. Regression analysis gave constants of C1 = 16.5 and C2 = 37.5 for WLF (Γ = 0.95), and κ = 1018.6 and m = 8.5 for power-law (Γ = 0.97) models. © 1994 Academic Press.