酵母多糖的提取、水解及组分分析

Extraction,hydrolysis and component analysis of zymosan

目的对啤酒酵母多糖进行提取和水解,并对获得的酵母多糖组分进行分析。方法采用碱法-酶法提取啤酒酵母多糖,并进行提纯,采用苯酚-硫酸法测定所提取多糖中的总糖含量,并计算多糖收率,凯氏定氮法测定蛋白含量。用三氟乙酸法(trifluoroacetic acid,TFA)水解多糖,采用Waters suger park-1色谱柱和蒸发光检测器进行液相检测,以确定不同酵母多糖的组分。结果获得的3种酵母多糖成分DT1、DT2、DT3的总糖含量分别为94.61%、95.89%、94.56%,收率分别为9.3%、3.6%、23.4%,各多糖的蛋白含量分别为2.98%、1.89%、3.34%。用2 mol/L的TFA,于110℃下水解6 h,对标准葡聚糖的水解率可达95%,且对3种酵母多糖均有较好的水解效果。通过碱法-酶法可获得甘露聚糖DT1;可溶性葡聚糖DT2,葡聚糖含量占总糖含量的90.6%;不溶性葡聚糖DT3,葡聚糖含量占总糖含量的98%以上;3种多糖均含有少量的蛋白质。结论碱法-酶法提取酵母可获得3种高纯度的酵母多糖,2 mol/L的TFA在110℃下对酵母多糖水解6 h,适于多糖组分的分离分析。

Objective To extract, hydrolyze and analyze the zymosan component of brewer yeast. Methods Zymosan was extracted by alkali extraetion-enzymolysis, then purified and determined for total sugar content by phenol-sulfuric acid method and calculated for recovery rate. The protein content was determined by Kjeldahl method. The zymosans were hydrolyzed by trifluoroacetic acid （TFA） method, and determined for component by HPLC using Waters sugar park-1 col- umn and evaporative light detector. Results The total sugar contents in three extracted zymosans DT1, DT2 and DT3 were 94. 61%, 95. 89% and 94. 56%, while the recovery rates were 9. 3%, 3. 6% and 23.4%, and protein contents were 2. 98%, 1.89% and 3.34%, respectively. The hydrolysis rate of glucan standard with 2 mol/L TFA at 110 ℃ for 6 h reached 95%, and satisfactory hydrolysis effect were also observed in three kinds of zymosans. By means of alkali ex- traction-enzymolysis process, three kinds of zymosans were obtained, i.e. mannan DT1, soluble glucan DT2 in which glu- can accounted for 90. 6% of total sugar content, and insoluble glucan DT3 in which glucan accounted for more than 98% of total sugar content. Each of the three kinds of zymosans contained a small quantity of protein. Conclusion Three highly purified zymosans were obtained by alkali extraction-enzymolysis process. Hydrolysis with 2 mol/L TFA at 110 ~C for 6 h was suitable for isolation and analysis of polysaccharide component.