摘要:
Objective To extract and separate polysaccharides from different sources of Eucheuma,investigate their physicochemical properties and compare their structural characteristics.Methods Polysaccharides from Eucheuma were successively extracted by cold water and hot water (80 °C).The crude polysaccharides were precipitated by ethanol,dialyzed,concentrated and finally subjected to lyophilization.Their physicochemical properties including the content of total sugar,protein and sulphate,molecular mass and monosaccharide compositions were determined by phenol-sulfuric acid,Folin-phenol,ion chromatography (IC) and high performance liquid chromatography (HPLC) methods.The structure of polysaccharides was characterized and compared by Fourier Transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (13 C-NMR) spectroscopy.Results Twelve sulfated polysaccharides were obtained from six kinds of Eucheuma.Total sugar content was 55%~75%,protein was 2.4%8.9%,sulphate content was 19.9%~35.1%,and molecular mass was 238~861 kDa,respectively.Monosaccharide composition analysis showed that all polysaccharides were mainly composed of galactose and a small amount of glucose or trace amount of xylose.These results demonstrated that EMP-C,EMI-C,EST-C,ESI-C,EDT-C,EST-H,ESI-H and EDT-H were mainly consisted of t-carrageenan,and EMP-H,EMI-H mainly contained κ-carrageenan,EGH-C mainly contained γ-carrageenan,EGH-H mainly contained v-carrageenan.However,EGH-C and EGH-H also contained a trace amount of κ-carrageenan.Conclusion These data provided useful reference for the optimal algal sources to prepare different types of carrageenan.%目的 从不同来源麒麟菜中提取分离多糖,分析其理化性质,比较其结构差异.方法 将6种麒麟菜依次采用冷水和80°C热水提取,提取液经乙醇沉淀、透析及浓缩冻干后获得麒麟菜多糖;分别采用硫酸-苯酚法、Folin-酚法、离子色谱法(IC)、高效液相色谱法(HPLC)等对其总糖、蛋白质、硫酸根含量、分子质量和单糖组成等理化性质进行分析,并采用傅里叶变换红外光谱(FTIR)和核磁共振碳谱(13C-NMR)对其结构进行比较.结果 从6种麒麟菜中提取获得12种硫酸多糖,其总糖、蛋白质和硫酸根含量分别在55%~75%、2.4%~8.9%和19.9%~35.1%之间,多糖分子量在238~861 kDa之间.单糖组成分析表明,各多糖主要由半乳糖以及少量葡萄糖或者木糖组成.EMP-C、EMI-C、EST-C、ESI-C、EDT-C、EST-H、ESI-H和EDT-H主要为α-卡拉胶,EMP-H和EMI-H主要为κ-卡拉胶,EGH-C主要为γ-卡拉胶,含有少量κ-卡拉胶,EGH-H除含有ν-卡拉胶外,尚有少量κ-卡拉胶.结论 不同来源麒麟菜多糖的结构不同,为不同结构卡拉胶藻源的选择提供了重要参考.