Abstract:

Crude Sargassum fusiformis polysaccharides (SEPS) were obtained by ultrasonic-assisted hot water extraction and purified by adding H2O2 or active carbon to remove color followed by adding trichloroacetic acid to remove protein. The ultrasonicassisted hot water extraction procedure was optimized using L16(45) orthogonal array design and the decolorization effects by H2O2 and active carbon were compared. In addition, the scavenging activity of SEPS against hydroxyl radicals generated by Fenton system was evaluated. A maximum yield of SEPS of 6.60 % was obtained under the following conditions: solid/liquid ratio 1:40, ultrasonic treatment 20 min, and temperature 100 ℃ for a water bath extraction duration of 150 min. There was a good linear relationship between hydroxyl radical scavenging activity and concentration of purified SEPS in the range of 0.05－0.50 mg/ml, with a coefficient of 0.9959, and the hydroxyl radical scavenging rate at 0.50 g/L reached 42.2%.

Key words: Sargassum fusiforme, polysaccharide, extraction, free radical