Alginate is a natural polysaccharide extracted from
brown sea algae (Phaeophyceae), and it is composed of
two uronic acids: β-D-mannuronic acid and α-L-guluronic
acid. Sodium alginate is composed of block polymers of
sodium poly(L-guluronate), sodium poly(D-mannuronate)
and alternating sequences of both sugars. Alginate is known
as a hydrophilic biopolymer that has a coating function
because of its well-studied unique colloidal properties,
which include its use for thickening, suspension forming,
gel forming and emulsion stabilising (Acevedo et al. 2010).
Sodium alginate has been effective on maintaining postharvest
quality of tomato (Zapata et al. 2008) and peach
(Maftoonazad et al. 2008).