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Rheological Properties of Wheat (Halberd) Amylopectin
Author(s) -
Tako Masakuni,
Hizukuri Susumu
Publication year - 2003
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.200300138
Subject(s) - amylopectin , aqueous solution , dynamic mechanical analysis , dynamic modulus , rheology , chemistry , urea , materials science , amylose , organic chemistry , composite material , polymer , starch
The non‐Newtonian flow behavior and dynamic viscoelasticity of wheat (Halberd) amylopectin in aqueous solution were investigated. The flow curves of Halberd amylopectin at 25 °C showed shear‐thinning behavior at various concentrations (2.0, 4.0 and 6.0%). The viscosity decreased gradually with increase in temperature at all concentrations investigated. The storage modulus of Halberd amylopectin was rather small and decreased gradually during increase in temperature even in 6.0% solution. The tan δ showed a value of 1.8 at 6.0% even at low temperature (0 °C) and increased slightly with increase in temperature. The storage modulus of Halberd amylopectin (6.0%) increased slightly upon addition of urea (4.0 M) and decreased gradually with increase in temperature. The storage modulus was higher in 0.05 M aqueous NaOH solution (6.0%) than in pure water. However, for tan δ almost the same values were observed in aqueous urea (tan δ = 1.7) and in alkaline (tan δ = 1.6) solution as in pure water (tan δ = 1.8). The storage modulus had a very large value in 85% DMSO. However, the tan δ value in DMSO was almost identical to that in aqueous solution. The results obtained led to the suggestion that in aqueous solution the wheat (Halberd) amylopectin molecules might be involved to a little extent in secondary associations. The structure of wheat (Halberd) amylopectin molecules seems to be different from that of rice amylopectin molecules.