The Open Macromolecules Journal

2014, 7 : 1-6
Published online 2014 January 24. DOI: 10.2174/1874343901407010001
Publisher ID: TOMACROJ-7-1

Structure and Rheological Behaviour of Agar Extracted From Madagascar Sea Coast Algae

Marie Pascaline Rahelivao , Hanta Andriamanantoanina Hanta Andriamanantoanina , Alain Heyraud and Marguerite Rinaudo
the Centre National de Recherche sur l’Environnement (CNRE), BP 1739 Fiadanana, 101 Antananarivo, Madagascar;

ABSTRACT

Polysaccharide from an original red algae (Gelidium sp) was extracted with hot water, clarified, and precipitated in presence of ethanol. NMR spectroscopic analyses and chromatographic separation after complete hydrolysis showed that this polysaccharide was composed predominantly of a repeating-unit based on 4-O-3,6-anhydro-α-L-galactopyranose and 3-O-β-D-galactopyranose confirming their agar nature. The Gelidium sp agar (representing 16 w % on the basis of dried crude algae) has a regular chemical structure and forms strong gels in aqueous medium. Its rheological behavior is examined as a function of polymer concentration and temperature.

Keywords:

Red algae, Agarose, Hydrolysis, Gelation, H NMR, Gelation.