RHEOLOGICAL PROPERTIES OF HYDROCOLLOIDS IN THE PRESENCE OF SUCROSE AND MILK

Apparent viscosities of guar gum, locust bean gum, and sodium carboxymethylcellulose were measured at shear rates of 16-2620s^-1 in water, sucrose, milk, and sucrose/milk solutions. The effect of different heat treatments was also studied. For all solutions, a power law equation described the variation of relative viscosity with shear rate allowing comparison of their non-Newtonian behaviour. With the neutral hydrocolloids, the hydration was limited by the presence of sucrose and milk which reduced the effective length of the polymer molecules. The behaviour of the polyanionic hydrocolloid, Na CMC, although influenced by milk and sucrose separately, was controlled by milk in a milk/sucrose mixture. This is due to milk salts which reduced the intramolecular repulsions along the polyanion and substantially lowered its effective hydrated length.