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Molecular characterization of starch polysaccharides
Author(s) -
Vorwerg W.,
Burchard W.
Publication year - 1992
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19920610127
Subject(s) - amylopectin , rheology , light scattering , starch , dynamic light scattering , static light scattering , scattering , materials science , aqueous solution , fractal dimension , chemical engineering , chemistry , chemical physics , optics , fractal , nanotechnology , composite material , organic chemistry , amylose , nanoparticle , physics , mathematics , mathematical analysis , engineering
Light scattering and rheologic measurements have been carried out with native starch in DMSO and with degraded amylopectin of a starch hydrolysate in water at different temperatures. The measurements of dilute solutions in DMSO were made to get a reference for the molecularly dispersed state. In water association take place which under certain conditions leads to gelation. An aqueous solution of about 11.5% (w/w) degraded amylopectin was investigated in detail. Structural change was observed during cooling the solution below 20°C with both techniques. A fractal dimensions of about 2.5 was found at temperatures above 20°C indicating non‐swollen random aggregates. Light scattering proved to be the more sensitive method than rheology, but in both experiments a structural collapse was detectable. A fractal dimension of about 1 was now obtained which is characteristic for rigid, elongated supra‐structures. A certain time after this collapse an increase of loss and storage module and particle growth in light scattering were obtained. The crossing of the G' and G” was taken as point of gelation and the same gelling time was estimated from light scattering. Hence, the combination of oscillatory rheology with light scattering is an appropriate procedure for a thorough investigation of such complex, structure forming systems.