pulpThe water-soluble polysaccharides were prepared by hot-waterextraction . 2.5 kgof dragon fruit pulp were crushed into slurry and extracted with95% (v/v) ethanol in water at 60◦C for 3 h. The ethanol-solublechemicals were removed. After centrifugation, the pellets were col-lected for polysaccharide extraction. Ten-fold weight of water was added and incubated at 80◦C for 3 h. The polysaccharide fractionwas centrifuged and concentrated by a rotary vacuum evaporator at60◦C. Ethanol was added to a final concentration of 60%, and main-tained overnight at 4◦C. After centrifugation at 8000g for 20 min,the polysaccharide pellets were collected and lyophilized.