Alginates are polymers extracted from the cell walls of various brown algae, particularly the species Laminaria, Saccharina, Macrocystis, and Ascophyllum. They are composed of D-mannuronic acid and L-guluronic acid monomers, available in both acid and salt forms; the latter constitutes 40-47% of the dry weight of this brown algal biomass (Arasaki and Arasaki, 1983; Rasmussen and Morrissey, 2007).

Alginates are commonly applied as intermediate feedstock in the food and pharmaceutical industries as stabilizers for the preparation of emulsions and suspensions in ice cream, jam, cream, custard, lotions, and toothpaste but also as coatings for pills. Furthermore, they have found application in the production of paint, construction materials, glue, and paper as well as in the oil, photo, and textile industries (Radmer, 1996).

Besides these technological functions, alginates possess bioactivities, as depicted in Table 10.2. Positive favorable dietary effects of alginates upon faecal microbial fauna have been claimed, as well as prebiotic features (Wang, Han et al., 2006); for instance, the bioactive food additive Detoxal containins calcium alginate and exhibits antitoxic effects on hepatitis. Additionally, mannuronate surfactants derived from alginate have been applied in cosmetics, health products, and agrochemicals (Benvegnu and Sassi, 2010).