Rheological behavior of kuzu starch pastes

摘要

In the paper, a comprehensive study of rheological properties of 3% (w/v) Japanese kuzu starch pastes was conducted. To describe the experimental data obtained from oscillatory and creep tests, the new rheological model-which was a modification of the fractional Kelvin-Voigt model -was proposed. The model provided an accurate description of the dynamic data in a range of nearly seven logarithmic decades of oscillation frequency omega, with an average error equal to 4.7%. It allowed for a precise determination of 17 rheological parameters of the biopolymer in a function of temperature and time of pasting. These parameters have provided a lot of additional information about structure and viscoelastic properties of the test medium in comparison to the classical analysis of dynamic curves G' and G '' and shear creep compliance J(t). The study indicated that kuzu starch pastes were viscoelastic polydisperse solids. Rising temperature and time of pasting caused an increase in elastic properties and average molecular weight of the biopolymer. The analysis also showed that the specific pasting conditions, 80 degrees C, 15 min; 95 degrees C, 75 min; and 80 degrees C, 30 min, are particularly important from the point of view of structure and rheological properties of products in food, pharmaceutical, and cosmetics industry, respectively.