Abstract: Response surface methodology was used to optimize the extraction conditions of polysaccharides from Undaria pinnatifida. The effects of three independent variables, extraction time, extraction temperature and ratio of water to raw material were investigated by a central composite design. The experimental data were fitted to a second-order polynomial equation via multiple regression analysis and also examined with the appropriate statistical methods. The adjusted coefficient of determination(R_ADj²) for the model was 0.9171. An optimum extraction yield of 30.78% was obtained when the extraction temperature was 95℃, extraction time was 4.5 h, and the ratio of water to raw material was 35(mL/g). Under these conditions, validation experiments were done and the mean extraction yield of polysaccharides was 30.79%, which was in good agreement with the predicted model value.

Key words: Undaria pinnatifida, Optimization, Extraction, Polysaccharide, Response surface methodology