Xanthan and glucomannan mixtures: synergistic interactions and gelation.

The synergistic interaction between xanthan and glucomannan in solution and in the gel phase has been studied by circular dichroism spectroscopy and differential scanning calorimetry. The study in solution of the polysaccharidic mixture indicates a preferred stoichiometry of the interaction corresponding to a weight fraction of xanthan around 0.55. This finding is in reasonable agreement with the differential scanning calorimetry measurements carried out on the gel phase. Models from conformational analysis based on these results were formulated in terms of 1:1 and 2:1 Konjac glucomannan/xanthan molecular assemblies. The experimental and calculation results clearly indicate the involvement of the side chains of xanthan and suggest that the ordered portions of the macromolecular complex in solution act in the gel phase as junction zones.