Influence of amylose in starches on molar mass and aggregated structure insemidilute solution

The properties of starches in dilute and semidilute solutions were measured by static and dynamic light scattering. The weight average molar mass was found to depend on the amylose content. Using the definition of a weight av erage the molar mass of amylopectin in the starches could be derived and wa s found to be in all cases around 70x10(6) g/mol. The interaction in semidi lute solutions followed initially a universal law. At larger concentrations aggregation became effective and lead, induced by the amylose content, to gelation due to phase separation. The time dependent aggregation process co uld be followed by dynamic light scattering, which again revealed the stron g amylose influence.