瓜蒌皮粗多糖提取方法与膜分离纯化条件的筛选

为获得含量和纯度较高的瓜蒌皮多糖,保证其生物活性,采用UF-100膜分离法对瓜蒌皮粗多糖进行分离纯化,比较不同操作压力、料液温度和运行时间下超滤膜和纳滤膜对多糖渗透通量的影响,测定瓜蒌皮多糖各截留液总糖含量,并与水提醇沉法进行比较。结果表明:超滤膜在操作压力0.14 Mpa,溶液温度25℃,每次过膜时间不超过2h的多糖膜通量最大,为88.5L/(m2·h);纳滤膜在操作压力0.4 Mpa,溶液温度25℃,每次过膜时间不超过2h的多糖膜通量最大,为7.1L/(m2·h)。该条件下,测得UF-100,UF-50、UF-10、UF-5、NF-800、NF-400、NF-200和NF-200以下8个膜段的瓜蒌皮总糖含量分别为13.52%、8.75%、13.06%、5.61%、5.29%、4.91%、4.88%和4.59%。UF-100膜分离和水提醇沉的瓜蒌皮多糖得率分别为10.06%和7.81%,膜分离瓜蒌皮多糖的得率较高。各截留段中,相对分子质量在1万以上的总糖含量较高,相对分子质量在5 000以下的总糖含量较低。

Extracting Methods of Crude Polysaccharides from Pericarpium Trichosanthes and Screening Conditions of Membrane Separation and Purification

In order to obtain the polysaccharides with high content and purity,and ensure the bioactivity of polysaccharides,the crude polysaccharides of pericarpium Trichosanthes were separated and purified by UF-100 membrane separation method.The effects of ultrafiltration membrane and nanofiltration membrane on the permeation flux of polysaccharides were compared under different operation pressure,solution temperature and operation time.And the content of total sugar in each cut-off liquid were determined,then the yield of polysaccharides was compared with water extraction and alcohol precipitation method.Results:The optimum conditions were the ultrafihration membrane flux was 88.5 L/ m2 h when the operation pressure was 0.14 Mpa,the solution temperature was 25℃ and the operation time was not more than 2 h.The nanofiltration membrane flux was 7.1 L/m2 · h when the operation pressure was 0.4 Mpa,the solution temperature was 25℃ and the operation time was not more than 2 h.Under these conditions,the total sugar content of pericarpium Trichosanthes of UF-100,UF-50,UF-10,UF-5,NF-800,NF-400,NF-200 and below NF-200 were 13.52％,8.75％,13.06％,5.61％,5.29％,4.91％,4.88％ and 4.59％ respectively.The yield of polysaccharides of pericarpium Trichosanthes after UF-100 membrane separation showed 10.06％ were higher than that after water extraction and ethanol precipitation which was 7.81％.The content of total sugar with relative molecular weight above 10 000 were higher,and the relative molecular weight less than 5 000 were lower.