Extraction, Primary Structure and Properties Investigation of Polysaccharides from Ulva lactuca L.

In NaOH solution, polysaccharides (ULP) were extracted from Ulva lactuca L., and the alcohol precipitation and purification were performed. The contents of polysaccharides, protein, uronic acid, and sulfate group were determined and the structure of polysaccharides were analyzed. The extraction conditions were optimized through single factor experiments and orthogonal experiments. The results indicated that it was under the conditions of 2% NaOH, 90 ℃, material/water ratio 1:80, liquid extraction 5 h and subsequent ultrasound-assisted extraction 1h that the highest yield of 17.57% was obtained. The physic-chemical characters of ULP were analyzed, the molecular weight and purity were determined. The infrared spectrum analysis, element analysis and surface activity test were also performed.