title: On the structure of kappa/iota-hybrid carrageenans.
abstract: The coil-to-helix transition and temperature dependence of the viscosity of commercial kappa/iota-hybrid carrageenans produced by the red algae Sarcothalia crispata, Mazaella laminarioides, and Chondrus crispus were studied using rheometry and optical rotation. The structure of these kappa/iota-hybrid carrageenans was determined by 1H and 13C NMR spectroscopy combined with monosaccharide composition analysis. The coil-to-helix transitions, measured by polarimetry and rheometry, of the kappa/iota-hybrid carrageenans are significantly different from those of pure kappa- and iota-carrageenan, and from hand-made mixtures thereof. This provides evidence that the kappa/iota-hybrid carrageenans are mixed chains, containing both kappa- and iota-repeating units.
authors.affiliation: Wageningen Centre for Food Sciences, The Netherlands. fvelde@nizo.nl
authors.forename: F
authors.initials: F
authors.lastname: van de Velde
authors.forename: H A
authors.initials: HA
authors.lastname: Peppelman
authors.forename: H S
authors.initials: HS
authors.lastname: Rollema
authors.forename: R H
authors.initials: RH
authors.lastname: Tromp
mesh_terms: D002236:Carbohydrate Conformation; D002351:Carrageenan / Q000737:chemistry*; D009005:Monosaccharides / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular; D009904:Optical Rotation; D011189:Potassium Chloride / Q000494:pharmacology; D000461:Rhodophyta / Q000737:chemistry; D013696:Temperature; D014783:Viscosity
chemical_list: D009005:Monosaccharides; D011189:Potassium Chloride; D002351:Carrageenan