【作者】 李磊；

【导师】 王岳飞；

【作者基本信息】 浙江大学 ， 茶学， 2008， 硕士

【摘要】 为了从果蔬和药食同源等素材中筛选具有抗氧化活性的功能因子,确定具有开发价值的功能素材,建立相应的原料抗氧化活性的分析标准,确定抗氧化功能因子的分析方法。选取了茶多酚、维生素C、葡萄籽提取物、山茱萸提取物、熊果酸等抗氧化物质进行抗氧化活性比较研究,选择由Benzie和Strain建立的铁离子还原法(ferric reducing/antioxidant power assay,FRAP)测定待测样品。山茱萸提取物的提取制备实验中通过预实验和正交实验选定最优提取参数即酒精浓度为85%,提取温度50℃,超声功率100W,超声时间30min。FRAP法的测定结果可以用来反映样品总的抗氧化能力。抗氧化能力的测定分为单种抗氧化物质抗氧化能力测定和几种抗氧化物质的协同抗氧化能力测定两部分进行研究。结果表明抗氧化物质的有效浓度对其抗氧化能力强弱起关键作用,茶多酚在较低浓度0.01mg/mL时抗氧化能力很低,低于维生素C的抗氧化能力,但是随着有效浓度的提高,当大于0.05mg/mL时抗氧化能力一直高于维生素C;协同实验结果表明EGCG在儿茶素中比例为40%-50%时抗氧化能力最强。抗氧化物质之间的协同抗氧化作用与抗氧化物质本身的抗氧化能力,抗氧化物质有效浓度的高低等因素有关。抗氧化物质之间的协同作用,在抗氧化物质本身有效浓度较低时协同作用也较低,随着有效浓度增加,协同抗氧化作用增加,达到一个峰值后,随着有效浓度的继续增加,协同作用会逐渐减弱。在应用FRAP法测定总的抗氧化能力的基础上进一步进行了抗氧化功能动物实验,研究结果表明茶多酚的抗氧化功能动物实验结果为阳性,证实了茶多酚的抗氧化功能以及其良好的清除自由基、延缓衰老的保健功效。更多还原

【Abstract】 In order to select functional factors from fruits, vegetables and other plants as food and medicine, we determined the antioxidant activity with ferric reducing /antioxidant power assay(FRAP) established by Benzie and Strain. Tea polyphenol(TP), vitamin c, grape seed extract, extract of the fruit of Cornus Officinalis , ursolic acid etc. were selected in this research. Extract of the fruit of Cornus Officinalis and american ginseng were extracted in our own lab. In the extraction experiment of the fruit of Cornus Officinalis, optimal extracting parameters were selected by preliminary and orthogonal experiment. The results were as follows: alcohol 85%, extraction temperature 50℃,ultrasonic power 100W and time 30min.FRAP can be used to determine the total antioxidant activity of natural antioxidants. Antioxidant activity of single sample determined by FRAP showed that the effective concentration of antioxidant played a key role in antioxidant activity. The results showed that TP in lower concentration(0.01mg/mL) had a lower antioxidant activity than vitamin c. When the concentration reached 0.05mg/mL, the result of antioxidant activity was contrary. In the cooperative antioxidant research, TP with different concentration of EGCG was determined by FRAP. The result showed that it had the highest antioxidant activity when the concentration of EGCG in catechin was 40%-50%.The cooperative antioxidant activity of antioxidants related to the antioxidant activity of antioxidants themselves and the effective concentration of antioxidants. Firstly, when the effective concentration of antioxidants was low the cooperative antioxidant activity was weak, then it became stronger as the concentration increased until the maximum cooperative antioxidant activity. As the concentration went on increasing, the cooperative antioxidant activity would not increase.The animal experiment of antioxidant function was taken at the base of the determination of the total antioxidant activity by FRAP. It showed that the result of the animal experiment of antioxidant function of TP was positive. The calculated results proved that TP had good antioxidant activity and healthy function in scavenging free radicals and delaying aging.更多还原