Galactans: an overview of their most important sourcing and applications as natural polysaccharides

Since last decades, lot of biological and rheological properties of polysaccharides and oligosaccharides were described. Among them, galactans and more especially sulfated galactans from seaweeds have shown interesting and specific properties not only as texturing agents but also as biological active compounds on several organisms. This class of polysaccharides includes classical sulfated galactans extracted from seaweeds and classified as agar and carrageenans. However, some galactans are more complex and their specific structural features have been characterized after their extraction from terrestrial plants, seaweeds but also animals and microoragnisms. This review catalogues the origins, structural characteristics and potentialities of these polysaccharides and their oligosaccharides derivatives.