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Rheology of Rice Starch‐Sucrose Composites
Author(s) -
Yoo Dongryel,
Yoo Byoungseung
Publication year - 2005
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.200400356
Subject(s) - sucrose , rheology , starch , shear thinning , viscosity , materials science , composite material , consistency index , chemistry , food science
The effect of sucrose at different concentrations (0, 10, 20 and 30%) on rheological properties of rice starch pastes (5% w/w) was investigated in steady and dynamic shear. The steady shear properties of rice starch‐sucrose composites were determined from rheological parameters for power law and Casson flow models. At 25°C all the starch‐sucrose composites exhibited a shear‐thinning flow behavior ( n =0.25–0.44). The presence of sucrose resulted in the decrease in consistency index ( K ), apparent viscosity ( η a,100 ) and yield stress ( σ oc ). Dynamic frequency sweeps at 25°C indicated that starch‐sucrose composites exhibited weak gel‐like behavior with storage moduli ( G ′) higher than loss moduli ( G ′′). G ′ and G ′′ values decreased with the increase in sucrose concentration. The dynamic ( η *) and steady‐shear ( η a ) viscosities at various sucrose concentrations did not follow the Cox‐Merz superposition rule. G ′ values as a function of aging time (10 h) at 4°C showed a pseudoplateau region at long aging times. In general, the values of G ′ and G ′′ in rice starch‐sucrose composites were reduced in the presence of sucrose and depended on sucrose concentration.