Characterization of Polysaccharides Extracted from the Carragenophyte Seaweed Rhabdonia

M.E.CROCE; E.R. PARODI; M.A. VILLAR

Ciudad Autónoma de Buenos Aires

Workshop; II Workshop on Bio-degradable Polymers and Biocomposites y III Workshop BIOPURFIL, Bio-based Polyurethane Composites with Natural Fillers; 2015

Facultad de Ingeniería, UBA

Carrageenans are natural polysaccharides with excellent physical properties as thickeners and stabilizers. These biopolymers are obtained from several seaweed species of the order Gigartinales, which are commercially exploited worldwide.In Argentina, the presence of large populations of the carragenophyte seaweed Rhabdonia (Order Gigartinales, Family Areschougiaceae) represents a potential economic resource for the production of biopolymers in the phycocolloids industry.In this study, the polysaccharides extracted from Rhabdonia were characterized by FT-IR spectroscopy and rheology. The yield of extraction for the polysaccharides of Rhabdonia was 35 %, similar to values reported on this genus.According to the FTIR spectra, extracted polysaccharides were identified as iota-carrageenans with high degree of sulfation. The presence of SO4= groups in C4 of D-galactose subunit and in C2 of 3,6-anhidrogalactosa subunits was evidenced by the bands at 850 and 803 cm-1. Viscoelastic properties of the gels were similar to those of a commercial carrageenan with elastic modulus (G´) values lower than 100 Pa. Gels showed an elastic behavior in frequencies from 0.1 to 10 rad/s, with an increase in both modulus at high frequencies.