火龙果果皮色素的提取及其抗氧化活性的研究

以火龙果果皮为原料,采用乙醇为提取剂对火龙果皮色素进行提取,利用正交设计实验优化其提取工艺,并采用体外模型从羟自由基（·OH）的清除能力,DPPH自由基（DPPH·）的清除能力和超氧阴离子清除能力三个角度评价其抗氧化活性。结果表明,色素提取液清除DPPH自由基的最优工艺条件是:选用90%的乙醇作提取溶剂,提取时间为180min,料液比为1∶16（g/mL）,温度为25℃,此条件下的DPPH·清除率可达到94.68%;火龙果果皮色素清除50%DPPH·、·OH与O-2·的有效浓度（IC50）分别为2.09、46.0、2.44mg/mL。火龙果皮色素提取液对DPPH自由基的清除作用在一定的范围内呈对数递增;对超氧自由基的清除作用和羟基自由基的清除作用与其浓度呈正相关。 

Extraction and antioxidant activity of pigment from pitaya peel

The pigment from pitaya peel was extracted by ethanol, orthogonal experiment was used to optimize the extraction process, antioxidant activities in vitro were evaluated in three systems as follow:hydroxyl radical (·OH) scavenging capacity, DPPH· scavenging capacity and superoxide anion radical scavenging capacity. The results showed that the optimum parameters of extracting pigment from pitaya peel for DPPH· scavenging capacity were 90% of ethanol as extraction solvent, 3h extraction time, 1∶16 (g/mL) liquid materials at 25℃ and DPPH· scavenging capacity was 94.68%. The 50% inhibitory concentrations (IC50 value) on scavenging DPPH·, ·OH and O-2· were respectively 2.09, 46. 0 and 2.44mg/mL. The pigment extraction exhibited a concentration-dependent radical scavenging activity in three systems.