title: The effect of salt content on the structure of iota-carrageenan systems: (23)Na DQF NMR and rheological studies.
abstract: (23)Na NMR spectroscopy has been used to study the effects of Na(+) ion concentrations on the structure of 1% (w/w) iota-carrageenan systems, a natural gelling polysaccharide used as a thickener in the food industry. Rheological and (23)Na T(1) relaxation time measurements revealed that gel formation correlates with decreases in ion mobility over the range of 0-3% (w/w) sodium content. (23)Na single-quantum (SQ) and double-quantum-filtered (DQF) NMR experiments performed on these systems provided evidence for a 'bound' sodium ion fraction in a specifically ordered environment. These results have allowed us to propose a model for the carrageenan gelation mechanism in the presence of Na(+) ions.
authors.affiliation: INRA, UMR1129 FLAVIC, F-21000 Dijon, France.
authors.forename: Mallory
authors.initials: M
authors.lastname: Gobet
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mouaddab
authors.forename: Nathalie
authors.initials: N
authors.lastname: Cayot
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Bonny
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Guichard
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Le Quéré
authors.forename: Céline
authors.initials: C
authors.lastname: Moreau
authors.forename: Loïc
authors.initials: L
authors.lastname: Foucat
mesh_terms: D002351:Carrageenan / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D011789:Quantum Theory; D012212:Rheology; D012965:Sodium Chloride / Q000737:chemistry*; D012975:Sodium Isotopes
chemical_list: D012975:Sodium Isotopes; D012965:Sodium Chloride; D002351:Carrageenan