绿茶中茶多酚的提取工艺研究

Technical Research of Tea Polyphenols Extraction from Green Tea

从绿茶中提取茶多酚,研究不同提取方法、乙醇浓度、提取温度、提取时间、沉淀茶多酚pH 5个单因素对提取结果的影响,提出最佳工艺条件为:质量分数70%乙醇水溶液作为提取液,料液比为1∶20,提取温度为70℃,提取时间为2 h,离子沉淀条件为Zn2+作为沉淀剂,质量分数为15%的NaHCO3水溶液调节pH为6.0,茶多酚沉淀转溶条件最佳表现组合为:A2B1C2D3,即茶多酚沉淀用2 mol/L硫酸溶液,料酸体积比为1∶2,于20℃转溶15 min较为合适。

In this study, the rate of tea polyphenols extraction from green tea, including alcohol concentration, temperature, extraction duration and pH value, were evaluated using orthogonal experiment. The optimal extraction points were listed as followings： 70% ethanol solution, an 1/10 ratio of tea to extractant, 70 ℃ temperature, 2 h duration, Zn2＋ precipitator and about 6.0 pH value that was mediated by 15% NaHCO3 solution. The dissolution of precipitated tea polyphenols reached its highest on the conditions of using 2 mol/L sulphuric acid as solution at a 1/2 ratio of tea polyphenols to the solution, and at 20 ℃ temperature with 15 min duration.