Physicochemical characterization of Gracilaria chouae sulfated polysaccharides and their antioxidant potential.

A complete absence of the physicochemical characterization of Gracilaria chouae polysaccharides (GCP) and its corresponding bioactivities urged the need for this study. It was found that GCP is a heteropolysaccharide which exists in linear random coil conformation. It contained a sulfate content of 7.9% in addition to 52.63% total sugar content and 9.62% galacturonic acid. Galactose and 3,6-anhydrogalactose were found in a molar ratio of 1.0:0.6. Its setting and melting points were determined as 41.3 and 71.7 °C, respectively, which makes it a suitable candidate for industrial processing where further heating is required and/or where the end-product needs to have extended shelf life in hot climate. GCP demonstrated 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis and hydroxyl radical scavenging activity (36.86, 27.42 and 19.07% at 3 mg·ml-1). Moreover, the results also suggested its potential use as a prebiotic due to its perceived high fermentability.