用不同体积分数的乙醇(30%、60%、80%和100%)提取黑枣中的酚类物质,通过测定各提取物的总酚含量,确定提取溶剂的适宜浓度为80%(总酚含量为3.5mg/g)。在此基础上,以DPPH自由基法、OH·自由基法、Fe~(3+)还原力法和Fe~(2+)络合力法对黑枣提取物的抗氧化活性进行了评价。结果表明:黑枣80%乙醇提取物具有较强的抗氧化活性,且其DPPH自由基、OH·自由基清除能力和Fe~(3+)还原能力均呈现剂量-效应关系,Fe~(2+)络合能力相当于5.64mgNa_2EDTA。

A comparison was made on the extraction of phenolic compounds from dates pulp(Diospyros lotus L.) with different concentrations of ethanol.The result showed that ethanol with a concentration of 80%was a suitable solvent to extract phenolic compounds.Antioxidant activities of the extract with 80%ethanol concentration were measured by DPPH,hydroxyl radical scavenging activities,reducing power and chelating activity assays.The results showed that DPPH and OH radical scavenging activities and reducing power of the extracts was concentration-dependent. Chelating activity of the extract in its Na_2EDTA equivalent was 5.64mg.