title: The influence of the six constituent xanthan repeating units on the order-disorder transition of xanthan.
abstract: Xanthans occurring in different levels of disordered conformation were enzymatically hydrolyzed to their six pentamer repeating units (RUs). The RUs present in the enzyme digests were analyzed using LC-MS. As only disordered xanthan segments are degraded by cellulases, the influence of the six different RUs on the transitional behavior of xanthan could be studied. The results indicate that especially xanthan segments rich in RUs that are acetylated on the outer mannose unit stabilize the xanthan conformation. Acetylation of the inner mannose did not show to have a clear stabilizing effect on the xanthan conformation. As the enzymatic release of pyruvylated RUs gradually increased with increasing levels of disordered xanthan segments, it is concluded that the distribution of these RUs is random. On the contrary, single and double acetylated RUs are distributed over specific xanthan segments as these RUs were instantly hydrolyzed.
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Marijn M
authors.initials: MM
authors.lastname: Kool
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
authors.affiliation: DUPONT, Danisco France SAS, 20 rue Brunel, 75017 Paris, France.
authors.forename: Graham
authors.initials: G
authors.lastname: Sworn
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Electronic address: henk.schols@wur.nl.
authors.forename: Henk A
authors.initials: HA
authors.lastname: Schols
mesh_terms: D002236:Carbohydrate Conformation; D006868:Hydrolysis; D008358:Mannose / Q000737:chemistry; D058105:Polymerization; D011135:Polysaccharides, Bacterial / Q000737:chemistry*
chemical_list: D011135:Polysaccharides, Bacterial; D008358:Mannose; C002563:xanthan gum
keywords: Acetylation pattern; Cellulases; Degree of substitution; LC–MS; Transitional behavior