On the structure of kappa/iota-hybrid carrageenans.
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.
van de Velde
F
F
Wageningen Centre for Food Sciences, The Netherlands. fvelde@nizo.nl
Peppelman
H A
HA
Rollema
H S
HS
Tromp
R H
RH
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
D009005:Monosaccharides; D011189:Potassium Chloride; D002351:Carrageenan