Gracilariopsis hommersandii, a red seaweed, source of agar and sulfated polysaccharides with unusual structures
Red seaweed Gracilariopsis hommersandii produces important amounts of non-gelling galactans, which were extracted with hot water (GrC, yield, 37%, viscosity average molecular weight, Mv 109 kDa), comprising agarose and sulfated galactan structures. The alkali modified derivative, GrCTr (Mv 95 kDa), gave a galactose:3,6-anhydrogalactose molar ratio of 1.0:0.9, and a more regular structure, favouring gelation (melting and gelling temperatures 64 and 14 °C, respectively). The rheological properties of this product suggest possible applications as hydrocolloid. G. hommersandii also biosynthesizes non gelling sulfated galactan fractions with diads constituted by β-D galactose and partially cyclized α-L-galactose units or non cyclized α-D-galactose residues. Sulfation was mainly detected on C6 or C4 of the β-D-galactose units, and on C6 and, in minor amounts, on C3 of the α-L-galactose units. The presence of β-apiuronic acid was demonstrated for these fractions as side chains of the galactan backbone. Carrageenan structures were found for the first time in an agarophyte of the Gracilariales.
| Main Authors: | , , , , , , |
|---|---|
| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | AGAR, SULFATED GALACTANS, GRACILARIOPSIS HOMMERSANDII, APIURONIC ACID, HYBRID GALACTANS, |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=46385 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|