超滤膜分离技术提取茶多酚的研究

Study on Clarifying Tiekuanyin Tea Juice of Ultra-filtration Technique and Extraction of Poly-phenols(TP) by Ion Depositing Method

以福建安溪铁观音茶叶的茶梗为原料,联合采用超滤法和沉淀法,水浸提其中活性成分茶多酚的最佳浸提条件为:温度(80±3)℃,料液比1∶20,浸提时间40 min.使用10万分子量的超滤膜,在25℃的温度下,驱动压力0.15 MPa,料液比1∶80下进行超滤,使茶叶中的活性成分得到保留的情况下有效地澄清了茶汁,改善了茶饮料的感官品质.进一步探讨了金属离子沉淀法自超滤后茶汁中提取茶多酚的条件,结果表明,最佳沉淀提取条件:Zn2+为沉淀剂,Na2CO3溶液调节pH=6.00,茶多酚的沉淀率为91.7%,纯度97.1%.

The tea poly-phenols （TP） were extracted by the methods of ultra-filtration combined with deposition from the stems of Tiekuanyin tea produced in Anxi, Fujian. The optimal conditions of leaching TP with water are as follows： temperature （80±3） ℃, ratio between material and liquor 1 ： 20, time 40 min. Using 10 thousand molecular weight of ultra-filtering membrane at the ultra-filtration condition of 25℃, 0. 15 MPa driving pressure, ratio between material and liquor 1 ： 80. So active components at tea are preserved,tea juice is clarified effectively and quality of sense for tea beverage is improved. Furthermore,the precipitating conditions of TP at tea juice after ultra-filtering are discussed by metal ion precipitation method. The appropriate conditions of precipitation method are： Zn^2＋ as precipitator,adjusting pH = 6. 00 of solution with Na2CO3 ,and the deposition rate and purity of TP are 91.7% and 97. 1% ,respectively.