Study on purification of burdock polysaccharide with membrane technology

The membrane technology for purify the polysaccharide extracts of Arctium Lappa L was studied.Firstly,the deproteinization effects of three methods were compared by the percentage of the deproteinization,polysaccharide loss with trichloroacetic acid method,Sevage method and tannic acid method.and The results showed that the best method was tannic acid method,the results were:the percentage of the deproteinization 67.87%,the percentage of losing polysaccharide 18.18%.Secondly,using the penetration flux and polysaccharide concentrations in permeation as index and the effects of different membranes,pressure and temperature on ultrafiltration were studied.Results showed the best conditions of purification to the polysaccharide were as follows:molecular weigh cut-off(MWCO)of memberane was 100000,the pressure was 0.25MPa and temperature of ultrafiltration was 40℃,the content and recovery ratio of polysaccharide were 25.8%,73.27% respectively.