Abstract
An agar was isolated from Gracilaria blodgettii HARVEY and its gelling properties were investigated. The total carbohydrates, uronic acid, nitrogen, ash, and moisture of the agar was estimated to be 88. 4, 1. 2, 0. 5, 3. 6, and 6.1%, respectively. The sulfuric acid was also estimated to be 1.4%. The D-galactose and 3, 6-anhydro-L-galactose residues were identified by paper and liquid chromatography from the acid hydrolysate of the agar. The optical rotation of the agar showed a value of -0.019° at a temperature of 60°C, then it decreased a little withdecreasing temperature. The infrared spectrum of the agar was in agreement with that of agarose in a wide range of wave numbers. Gelation occurred at a concentration of 0.2% at room temperature. The dynamic modulus increased with increasing concentration and showed very large value at a concentration of 0.15%. The dynamic modulus of the agar solution was stable as the temperature increased to 50°C. The agar extracted from Gracilaria blodgettiiHARVEY was estimated to have high quality in chemical components and in gelling properties.
