Rheological properties
The shape of the typical flow curves (Figure 1) of the goat’s milk yogurts (stirred) resembles the shape of the curves that is usually found for weakly aggregating dispersions (de Rooij and others 1993; Potanin 1993). The apparent viscosity of yogurt continuously decreases with increasing shear rate due to breakup of the aggregates. Eventually, when all aggregates are broken up and only colloidal particles are present, hydrodynamic forces dominate all other forces and the sample becomes Newtonian, that is, has a constant viscosity. The flow behaviors of Figure 1a and 1b were similar; Figure 1c had the highest apparent viscosity values, whereas Figure 1d had the lowest values at the low shear rate (