摘要：The shear stress/shear rate relations of 2.5, 5.0, 7.5 and 10% solutions of a commercial preparation of casein glycomacropeptide (80% GMP) were measured at 25, 35, 45, 55 and 65°C, respectively. The corresponding viscosities for the GMP solutions were calculated from these relations. Changes in apparent viscosity in relation to temperature suggest the formation of polymeric forms at ≥ 45°C. The shear stress/shear rate relations were found to fit the Hershly Bukly model with correlation coefficients close to unity. Calculating the yield stress suggested that it was affected markedly by the concentration and temperature. At 25°C, the apparent viscosity of 5% GMP solution decreased with the increase of pH from 3.4 to 8. At 45°C, GMP solutions exhibited higher viscosities than at 25°C and pH 3.4 and 5 but lower at pH 8. suggesting the formation of high molecular weight polymers. The shear stress/shear rate relations for the 2.5 and 7.5 GMP solutions at 25°C increased slightly to a maximum when 0.1-0.15% CaCl2 were added and to a maximum when 0.15-0.20% CaCl2 when measurements were carried out at 45°C.
