Polysaccharide gels carrageenan

Rees et al. (25) have extensively examined the solution conformation and interactions of a number of polysaccharides, especially carrageenan fractions. Kappa-carrageenan is unusual as it forms gels when a solution of its potassium salt is cooled. Rees conceives that double helix formation occurs in solution and, interlocking helices develop in the gel state. 

A preliminary study was also carried out in order to follow the gel-sol and sol-gel transitions of the thermoreversible polysaccharide /c-carrageenan under shearing conditions.389 The velocity profiles obtained at different temperatures enabled the effect of shear on the processes to be studied and an intermediate sol-like transition state to be detected. H NMR spectroscopy and T2 measurements were recorded, showing the presence of two dynamic spin populations, possibly arising from random coil segments and helical aggregated segments. 

Applications of sol-gel-processed interphase catalysts. Chemical Reviews, 102, 3543-3578. Pierre, A.C. (2004) The sol-gel encapsulation of enzymes. Biocatalysis and Biotransformation, 22, 145-170. Shchipunov, Yu.A. (2003) Sol-gel derived biomaterials of silica and carrageenans. Journal of Colloid and Interface Science, 268, 68-76. Shchipunov Yu.A. and Karpenko T.Yu. (2004) Hybrid polysaccharide-silica nanocomposites prepared by the sol-gel technique. Langmuir, 20, 3882-3887. 

---