Agars fromGracilaria chilensis (Gracilariales)

Abstract

The chemical composition of the agars extracted with water at 95 C fromGracilaria chilensis of Estero de Lenga (43.2% of yield) and of Bahia de Coquimbo (43.4% of yield) were determined. The gel strength, gel melting and gelation temperature of the agars were also measured. Polysaccharides obtained by extraction with cold water and by extraction of the alkali pre-treatedG. chilensis of Bahia de Coquimbo were also analyzed.The physical constants and the contents of sulfate and 3,6-anhydrogalactose of the alkali-modified agar fromG. chilensis of Estero de Lenga were comparable to those of commercial agar. This algae represents an excellent potential commercial resource of agar.G. chilensis of Bahia de Coquimbo gave hydrocolloids with low gel strength values more suitable for use in the food industry. Anion exchange chromatography of the agars obtained by extraction with water at 95 C indicated that the whole polysaccharides and all of the acidic fractions were not homogeneous. Neutral fractions comprised only about 25% of the agars.