title: Control of the properties of xanthan/glucomannan mixed gels by varying xanthan fine structure.
abstract: The interaction of native xanthan gum, deacetylated xanthan gum and depyruvated xanthan gum with konjac glucomannan has been studied using DSC and controlled stress rheometry. In the absence of electrolyte the DSC cooling curves for native xanthan and deacetylated xanthan showed a single peak and there was a corresponding sharp increase in the storage modulus indicating gel formation. It is apparent that on cooling, association of the konjac glucomannan with the native xanthan molecules is triggered by the xanthan coil-helix transition. In the presence of electrolyte, there were two DSC peaks observed. The higher temperature DSC peak was attributed to the xanthan coil-helix transition while the lower temperature DSC peak was attributed to konjac glucomannan-xanthan association as noted by an increase in the storage modulus. The gels formed were much weaker than those in the absence of electrolyte. The DSC cooling curves for depyruvated xanthan in the absence of electrolyte showed two peaks. The higher temperature peak was attributed to the coil-helix transition while the lower temperature peak corresponded to gelation as noted by an increase in the storage modulus. The gels were very much weaker than for native xanthan gum and deacetylated xanthan gum.
authors: Centre for Water Soluble Polymers, Glyndwr University, Plas Coch, Mold Road, Wrexham LL11 2AW, UK. paul.fitzpatrick@ctechinnovation.com
authors: P
authors: P
authors: Fitzpatrick
authors: J
authors: J
authors: Meadows
authors: I
authors: I
authors: Ratcliffe
authors: Peter A
authors: PA
authors: Williams
mesh_terms: D000215:Acylation; D002236:Carbohydrate Conformation; D004573:Electrolytes / Q000737:chemistry; D005782:Gels; D008351:Mannans / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D019289:Pyruvic Acid / Q000737:chemistry; D012212:Rheology; D013696:Temperature
chemical_list: D004573:Electrolytes; D005782:Gels; D008351:Mannans; D011135:Polysaccharides, Bacterial; C022901:(1-6)-alpha-glucomannan; D019289:Pyruvic Acid; C002563:xanthan gum