A time–temperature rheological study of konjac glucomannan hydrocolloid

Abstract

Konjac glucomannan (KGM) is one of the most versatile soluble biomaterials having wide-ranging applications. The shear storage, G', and loss, G", moduli of this hydrocolloid were recorded as functions of angular frequency varying from 0.1 to 100.0 rad/s and temperature from 5 to 50 degrees C. It was found that both G' and G" mainly increase with angular frequency in the range from 0.1 to 100 rad/s. As the temperature increases from 5 to 95 degrees C, the values of G' and G" decrease. A novel criterion for the thermorheologically simple material, and a procedure to calculate the shift factor from the angular frequency sweep and temperature ramp data were presented. By these methods, the KGM hydrocolloid is found to obey the TTS principle as log G" and log G' are less than 1.529 and 1.436, respectively. The Williams-Landel-Ferry equation can describe the shift factor of the KGM hydrocolloid.