Evaluation of viscoelasticity of high concentrated starch suspension using dynamic viscoelasticity measurements in xanthan-gum gel matrices

Viscoelasticity behavior of starches originated from various botanical sources during gelatinization was examined using the gel-dispersed dynamic viscoelasticity measurement (GDVM), which measures the viscoelasticity behavior of starches in a gel matrix during gelatinization, These results were compared with viscosity characteristics obtained from rapid visco-analysis (RVA). Viscoelasticity characteristics of starches were classified into root, glutinous grain, nonglutinous grain, and bean starches, using viscoelasticity modules (G',G". tan delta) obtained by GDVM at 6.6%, 10% and 33% starch concentration. It was explained using the revised Kerner's equation that GDVM viscoelasticity characteristics were reflected by the viscoelasticity of starch granules but that of xanthan-gum solutions. Viscoelasticity characteristics of starches except nonglutinous grain starches indicated mechanical properties of starch granules even if obtained at considerably low starch concentration, However, those characteristics of nonglutinous grain starches, swelling powers of which are relatively low, did not indicate the same properties when obtained at below 20% starch concentration. The starches were classified with viscosity characteristics of RVA as same as by GDVM. G' and G" at 6.6% starch concentration and G' at 10% were significantly correlated with all viscosity characteristics of RVA, and had the maximum correlation with final viscosity.