Viscosity properties of acetylated carboxymethyl starch.

The viscosity properties of acetylated carboxymethyl starch (ACMS) aqueous solution with different DS (degree of substitution) at concentration of 2.0% (w/w) were investigated using Brookfield R/S+ Portable rheometer. All flow curves of ACMS are well fitted to Power law model. Arrhenius model was used to describe temperature sensitivity. Furthermore, the parameters, which influenced the viscosity properties of the solutions, including temperature, DS of carboxymethyl group (DScm), DS of acetyl group (DSac), presence of salt (NaCl) and shear rate were discussed in detail. Specifically, the viscosity-stability, salt-tolerance and shear-resistance of ACMS with DScm (0.76) and DSac (0.34) were compared with that of sodium alginate as thickener in food or non-food applications. The results indicate that the viscosity properties of ACMS (DScm=0.76, DSac=0.34) were similar to that of sodium alginate and ACMS with DScm (0.76) and DSac (0.34) may be considered as a substitute for sodium alginate in certain application.