Effect of concentration on rheological properties of acid-hydrolyzed amylopectin solutions

Rheological properties are sensitive to variations in molecular structure and they are useful in developing structure-function relationships for systems of polysaccharides in solution. Intrinsic viscosities of acid-hydrolyzed Amioca starches in 90% DMSO/10% water were determined using a modified approach for polyelectrolytes. Double logarithmic plots of specific viscosity, eta(sp). against coil overlap parameter, c[eta], were made and trends in both the dilute and concentrated regimes were found to be similar to those seen with other polysaccharides. Dynamic frequency sweeps indicated that all acid-hydrolyzed starches in 90% DMSO/10% water exhibited dilute solution or liquid-like behavior with G " higher than G'. A contradiction in classification of 6-12% starch dispersions was found with shear tests (concentrated) and small strain oscillatory tests (dilute). (C) 2000 Elsevier Science Ltd. All rights reserved.