Extraction and concentration of phenolic compounds from terminalia chebula friuts

This study aimed to extract phenolic compounds from T.chebula fruits and concentrate the extract using sugaring out concentration process. The water-ethanol (EtOH) and water- propylene glycol (PG) solvent systems were used in extraction process and the design of experiment (DOE) was employed to determine the optimal extraction conditions (temperature, concentration of EtOH and PG and extraction time). The results showed the optimal condition for water-EtOH was obtained at the temperature of 76C and concentration of EtOH 76.4 %v/v and 82 min. For water-PG system, the optimal extraction condition was at temperature of 57C, PG concentration of 36%v/v and extraction time of 23 min. In sugaring out concentration of the extracts, glucose was added to the extracts that contained highest phenolic compounds in both solvent systems from the extraction experiment. The concentration of glucose that gave the desired phase separation ratio as well as the distribution coefficients of gallic acid (GA) and ellagic acid (EA), two major phenolic compounds in T. chbula, was determined 200 g/L for both water-EtOH and water-PG systems. The phase ratios for water-EtOH and water-PG were 1.94 and 1.85, respectively. The distribution coefficients of total phenolic for both solvent systems were the same, which was 1.98. Those of GA and EA were 4.89 and 3.52 for water-EtOH, and 4.34 and 3.22 for water-PG system, indicating that sugaring out concentration is a potentially effective method for pheonic compound concentration. Finally, the concentrated extracts show higher antioxidant activities than the nonconcentrated extracts and that antioxidant activity of extract in water-PG was higher than those of the water or water-EtOH extracts.本研究旨在从诃子（T.chebula）果实中提取酚类物质，并采用糖析浓缩法（sugaring out concentration）对提取物进行浓缩。提取过程中选用水-乙醇（EtOH）与水-丙二醇（PG）两种溶剂体系，并通过实验设计（Design of Experiment, DOE）确定最优提取条件（温度、溶剂体积分数及提取时长）。结果表明，水-乙醇体系的最优提取条件为：温度76℃、乙醇体积分数76.4%v/v、提取时长82 min；水-丙二醇体系的最优提取条件则为：温度57℃、丙二醇体积分数36%v/v、提取时长23 min。在提取物的糖析浓缩步骤中，本研究向两种溶剂体系提取所得的酚类含量最高的提取物中添加葡萄糖。经测定，两种溶剂体系达到目标相分离比例以及诃子中两种主要酚类物质——没食子酸（gallic acid, GA）与鞣花酸（ellagic acid, EA）——的分配系数所需的葡萄糖添加浓度均为200 g/L。水-乙醇体系与水-丙二醇体系的相分离比例分别为1.94和1.85。两种溶剂体系的总酚分配系数均为1.98；其中水-乙醇体系中没食子酸与鞣花酸的分配系数分别为4.89和3.52，水-丙二醇体系中则分别为4.34和3.22，这表明糖析浓缩法是一种颇具应用潜力的酚类物质浓缩手段。最后，浓缩后的提取物抗氧化活性均优于未浓缩提取物，且水-丙二醇体系提取物的抗氧化活性高于纯水体系与水-乙醇体系提取物。