Ulva fasciata polysaccharide and application thereof

The invention discloses ulva fasciata polysaccharide and application thereof. The ulva fasciata polysaccharide is prepared by the following steps: performing an ultrasonic auxiliary water extract and alcohol precipitation process on washed ulva fasciata as a raw material, thereby obtaining crude ulva fasciata polysaccharide; decoloring and removing protein from the crude ulva fasciata polysaccharide by using a radial flow chromatographic column by tan ion exchanger A103S as a packing; separating and purifying the crude ulva fasciata polysaccharide of which the color and the protein are removed by using the radial flow chromatographic column by taking Sephadex-G100 as a packing, thereby obtaining pure ulva fasciata polysaccharide with uniform molecular weight. The method for preparing the ulva fasciata polysaccharide has the characteristics of environment protection, rapidness, high efficiency and low cost, and is applicable to on-scale production; the contents of protein and the pigment in the prepared ulva fasciata polysaccharide are both relatively low, the relatively high purity is achieved, the molecular weight distribution is concentrated, the moisture absorption and retention property is improved, and the result that of ulva fasciata polysaccharide has the shearing thickening property is found for the first time. Therefore, the ulva fasciata polysaccharide disclosed by the invention can be used as a moisture absorption and retention agent or a thickening agent.