Figure 1.

Chemical structure of alginate and alginate gelling: (a) β-(1→4)-D-mannuronic acid (M) and α-(1→4)-L-guluronic acid (G) blocks; (b) egg-box model; (c) calcium coordination described by the pair of guluronate chains in calcium alginate junction zones. Dark circles represent the oxygen atoms involved in the coordination of the calcium ion. Adapted with permission from reference [93]. Copyright 2007 American Chemical Society.