A highly methylated agar from red seaweed, Gracilaria arcuata

A highly methylated agar was isolated from Gracilaria arcuata which was har vested from Ishigaki Island, Okinawa, Japan. The yield of the agar was 33.2 % (w/w dry algae). Gelation occurred at a concentration of 0.35% (w/v) at r oom temperature. The total carbohydrate, sulphate, ash and methoxyl content were 85.0, 0.8, 3.8 and 13.4% (w/w), respectively. The methylated sugar wa s identified as 6-O-methyl-D-galactose and 2-O-methyl-anhydro-L-galactose r esidues, respectively, by C-13- and H-1-NMR spectroscopy. The methylated ag ar was composed of D-galactose, 6-O-methyl-D-galactose, 3,6-anhydro-L-galac tose, and 2-O-methyl-3,6-anhydro-L-galactose.