Monocationic salts of carrageenans: Preparation and physico-chemical properties

Autor: Marju Robal, Kalle Truus, Shingo Matsukawa, Tom Brenner, Brian Rudolph, Rando Tuvikene, Hiroo Ogawa
Rok vydání: 2017
Předmět:
Zdroj: Food Hydrocolloids. 63:656-667
ISSN: 0268-005X
DOI: 10.1016/j.foodhyd.2016.09.032
Popis: Highly pure monocationic forms of κ-, ι-, λ-carrageenans and furcellaran were prepared with the aid of successive dialysis and ion exchange steps. Two approaches were used to obtain the samples: direct exchange of the galactan-bound cations with the aid of ion-exchange resin and generation of H+-forms of the polysaccharides followed by neutralization process. The galactan samples were characterized by 1H-NMR, 13C-NMR, pulsed-field-gradient stimulated echo 1H-NMR, FTIR, FT-Raman spectroscopy, ICP-OES, size exclusion chromatography, viscometry, static and dynamic rheometry methods. The ability of cations to enhance gelation follows the order of Li+ 1 × 105 Pa) in the presence of equal amounts of Rb+ and Sr2+ ions. The rheological properties are notably pH-dependent. Among the monocationic samples, Ba2+-forms of κ-carrageenan and furcellaran yield the strongest gels in alkaline media, whereas Rb+- and Cs+-forms show the highest gelling capacities under acidic conditions. The widely employed method involving excessive dialysis against water as the final purification step causes cation depletion, acidification of the carrageenan sample and significant degradation during the freeze-drying step.
Databáze: OpenAIRE
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