采用热水浸提法提取发菜多糖，确定发菜多糖的最佳提取工艺条件为：提取温度80 ℃，水料比为90:1，浸提时间为70 min，浸提次数为3次。采用乙醇沉淀法得到发菜多糖。紫外扫描显示发菜多糖不含核酸及蛋白质，红外光谱分析其具有多糖的特征吸收峰，为一种非硫酸化的以β-糖苷键为主的多糖，热重分析表明多糖的热降解温度为256.8 ℃。

The Nostoc flagelliform polysaccharide was extracted by hot water and the best extraction conditions were determined. The optimal temperature, ratio of water to algae (v/w), time, extraction times for the extraction of Nostoc flagelliform polysaccharide were 80 ℃, 90, 70 min and three times, respectively. Analysis of Nostoc flagelliform polysaccharide by UV spectrum showed that there were no absorption peaks of protein and nucleic acid at 280 nm and 260 nm, while the Fourier transform infrared spectrophotometer (FT-IR) analysis revealed that the sample has the typical characteristics of polysaccharide and was a non-sulfated polysaccharide with β-glycosides. Thermogravimetic analysis indicated that the degradation temperature of polysaccharide was 256.8 ℃.

国家自然科学基金（20376061），天津市科技发展计划重点基金（043801611）