Gelation occurs when divalent ions (Ca2+, Ba2+, Fe2+, Sr2+, etc.) or trivalent ions (Al3+, etc.) take part in the
interchain ionic binding between G-blocks in the polymer chain giving rise to a three dimensional network. Such
binding zones between the G-blocks are often referred to as “egg boxes”. These ions act as cross-linkers that
stabilize alginate chains forming a gel structure, which contains cross-linked chains interspersed with more
freely movable chains that bind and entrap large quantities of water. The gelification process is characterized by
a re-organisation of the gel network accompanied by the expulsion of water