Kappa-carrageenan gels gelation

Hermansson, A.M. (1989). Rheological and microstruetural evidence for transient states during gelation of kappa-carrageenan gels in the presence of potassium. Carbohydrate Polymers, 10, 163181. 

Substantial research efforts have been made to relate molecular properties to the structures of the junction zones and provide mechanisms for gel formation. Thus we have models for the formation and alignment of double helices for kappa-carrageenan, formation of triple helices for gelatin and egg box models for calcium induced gelation of alginate and pectin to mention a few examples (Morris 1986 Djabourov... 

The dependence of the gelation process of carrageenans on electrolyte concentration has been the subject of many investigations e.g. [522, 543-546,553-555, 561, 562, 566-568], In general, it was concluded that the alkali metal ions are able to increase the gelation tendencies of both iota and kappa carrageenans. The cation dependence of the gel modulus follows the Hofmeister series Cs" > Rb" > Na > Li , which is in agreement with what has been said... 

Rochas and Rinaudo [569] constructed a phase diagram, where the logarithm of the total ionic concentration is plotted vs the reciprocal transition temperature (see Fig. 221). It characterizes the conformation and gelation of kappa carrageenan in KCl solutions. In domain I (relatively low concentration and high temperatureX only polymer coils are present in domain II (relatively low concentration and low temperature), the kappa carrageenan molecules are in the ordered, helical conformation, whereas in domain in (relatively high concentration and low temperature the system is in the (helical) gel state the boundary between domains II and III is not sharply known and for that reason is indicated by a wavy line. 

---