Preparation and Analysis of Polysaccharides.

polysaccharides (PLPs) were obtained by a hot water extraction method. Starting from the single factor experiment, the extraction was optimized by response surface methodology, and the following optimal extraction parameters were obtained: the extraction temperature was 84 °C, the liquid-solid ratio was 11 mL/g, the extraction time was 73 min, and the extraction rate of polysaccharides was 8.59%. The Sevag method was used to remove the protein soluble in water and HO was used to remove the pigment; then PLPs were precipitated with three times of anhydrous ethanol, soluble salts and other small molecules were removed by dialysis, and finally refined PLPs were obtained by freeze-drying.