发菜多糖絮凝纯化及体外清除自由基分析

Flocculating Purification and Free Radical Scavenging of Polysaccharides from Nostoc Flagelliforme

采用天然高分子絮凝剂壳聚糖对发菜多糖水提液进行絮凝处理,以蛋白质去除率和多糖保留率为指标,通过单因素试验分析壳聚糖用量、絮凝时间、多糖提取液pH、温度对发菜多糖絮凝纯化效果的影响.实验结果表明:在pH为7的提取液中加入1.5mg/mL壳聚糖,在温度为40℃条件下絮凝处理60min,多糖保留率为90.3%,蛋白质去除率为75.1%;壳聚糖絮凝纯化后的多糖清除DPPH-和-OH的能力优于醇沉后多糖.

A major disadvantage of ethanol precipitation method is its high losing ratio of active ingredients.Therefore the technology of flocculation was used instead of the ethanol precipitation method.In this study,chitosan,which is a natural macromolecule flocculant,was used to flocculate Nostoc flagelliforme.polysaccharide extraction solution.Polysaccharides rentention rate and protein removel rate were taken as the guide lines to evaluate the effect of different influencing factors on flocculation The effects of chitosan dosage,flocculation time,pH,and temperature were investigated by single factor experiments,comparing with the traditional technique of alcohol precipitation.The optimal extraction parameters were determined as chitosan dosage 1.5 mg/mL,flocculation time 60 min,pH 7,and temperature 40℃,Under these conditions,75.1%of protein in the crude extract was removed,the retention rate of the polysaccharides was 90.3%.Compared with two different purification methods,the scavenging of DPPH-and-OH free radical by polysaccharide(extracts)from chitosan are stronger than that by polysaccharide extracts from alcohol precipitation.