Abstract: Potato starch was formed into sodium carboxymethyl starch (CMS) by solvent method, and the rheological properties of potato CMS in aqueous solutions were studied. Based on the fact that potato CMC can be dissolved and gelatinized at a low temperature, potato CMS aqueous solutions at concentrations of 0.5, 1.0, 2.0 g/100 mL and 4.0 g/100 mL were tested using a NDJ-9S rotation viscometer in a low-temperature range (20, 30, 40, 50 ℃ and 60 ℃) for their apparent viscosities at different shear rates, and a rheological model for potato CMS solutions was constructed, followed by deduction of rheological properties. In addition, the effects of adding sodium chloride at a concentration of 1.5 g/100 mL, citric acid at 0.2 g/100 mL or sugar at 5 g/100 mL on the rheological properties of 4 g/100 mL potato CMS solution were explored. Potato CMS solution was found to be a pseudo-plastic fluid, of which the apparent viscosity was markedly affected by temperature, concentration, shear rate, and so on. Adding sucrose had little effect on the rheological properties of potato CMS solution, while potato CMS solution displayed an obvious decline in its apparent viscosity and shear stress after addition of sodium chloride or citric acid.

Key words: sodium carboxymethyl starch (CMS), viscosity, rheology propeties, potato, starch, additive