川桑葚中鞣酸的提取及纯化工艺研究

Study on extraction and purification technology of tannic acid in Sichuan mulberry

对脱除多糖的桑葚干燥粉末先用N,N—二甲基甲酰胺提取鞣酸,再用石油醚和正丁酸甲酯萃取3次后获得鞣酸粗品。鞣酸粗品经酸沉、醇沉和重结晶3种方法纯化,采用单因素试验与正交试验优选鞣酸提取工艺和纯化工艺。结果发现:最佳提取工艺条件为N,N-二甲基甲酰胺与川桑葚质量比12∶1、石油醚与正丁酸甲酯体积比3∶1、提取温度40℃、提取时间8 h;最佳纯化工艺条件为酸沉时间16 h、醇沉时间4 h、重结晶温度50℃。

After removing polysaccharide from mulberry, tannic acid was extracted in the mulberry powder through N＇N-dimethyl-formamide（DMF）.Then raw tannic acid was obtained after extracting in mineral ether（ME） and methyl butyrate（MB） 3 times. Tannic acid was purified by acid precipitation, alcohol precipitation and recrystallization, Single factor test and orthogonal experiment were used to fi nd the best factor for extraction and purifi cation, the results showed that the optimum extraction conditions were as follows： weight ratio of DMF to Sichuan mulberry was 12 ∶ 1, volume ratio of ME to MB was 3 ∶ 1, temperature was 40 ℃, and time was 8 h. The best purifi cation conditions were as follows： time for acid precipitation was 16 h, time for alcohol precipitation was 4 h, the temperature for recrystallization was 50 ℃.