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Rheological Studies on Starch — Flow Behaviour of Wheat Starch Pastes
Author(s) -
Doublier J.L.
Publication year - 1981
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19810331205
Subject(s) - viscometer , rheology , shear thinning , materials science , starch , flow properties , newtonian fluid , viscosity , apparent viscosity , shear rate , flow (mathematics) , composite material , thermodynamics , chemistry , mechanics , organic chemistry , physics
Flow behaviour of wheat starch pastes has been studied over a large range of concentrations (0.3 to 8%) with a coaxial cylinders viscometer (Rheomat 30) and a highly sensitive viscometer (Low‐Shear 30). The flow curves indicated a non‐Newtonian and shear thinning behaviour with a Newtonian limit viscosity η° between 0.3% and 1.5%. Above this concentration, the flow curves could be described by an Ostwald‐De Waele equation over a limited range of shear rates. Moreover, for the highest concentrations a tendency to a yield stress was displayed. By comparing the effect on the flow curves of three preparation procedures, large differences were observed which were interpreted on the basis of particles dispersed in a macromolecular medium. The size of these particles and the composition of this macromolecular medium are determining for this flow behaviour.