Synergistic Interaction between Xanthan and Konjac Glucomannan in Aqueous Media

Abstract

The non-Newtonian behavior and dynamic modulus of a series of aqueous mixtures of xanthan (native, deacetylated, depyruvated, and deacylated) and konjac glucomannan were measured with a rheogoniometer. The flow curves, at 55°C, of a mixed solution of xanthan and glucomannan showed plastic behavior at 0.1% total gums. At a concentration of 0.1% total gums, gelation occurred at room temperature. A much stronger gel was observed in a mixture with deacetylated xanthan, about twice as strong as that of a mixture with depyruvated xanthan. The dynamic modulus of a mixture of deacylated xanthan and glucomannan stayed at very small value in the presence of CaCl₂. (6.8 mM) and urea (4.0 M). The side chains of xanthan may be dominant in the interaction with konjac glucomannan molecules.