Figure 3.

Scheme of carrageenan gel formation. The structure of κ- and ι-carrageenan allows segments of the two molecules to form the so-called double helices which bind the chain molecules in a three-dimension network. The associated counterions such as Na⁺, K⁺ and Ca²⁺, are also required to induce the sol-gel transition of the referred types of carrageenan.