Stratil Pavel, Klejdus Borivoj, Kubán Vlastimil
Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Zemedelská 1, CZ-613 00 Brno, Czech Republic.
J Agric Food Chem. 2006 Feb 8;54(3):607-16. doi: 10.1021/jf052334j.
This research studies in detail the contents of phenolic compounds determined by the Folin-Ciocalteu reagent and the antioxidant activities determined by the TEAC (Trolox equivalent antioxidant capacity), DPPH (using diphenyl-p-picrylhydrazyl radical), and FRAP (ferric reducing antioxidant power) methods, and their correlations for used standards with these methods (catechine, gallic acid, caffeic acid, ferulic acid, Trolox, ascorbic acid, and ferrous sulfate) and extracts from several species of commonly consumed vegetables were studied in detail. The comparison of absolute values of absorption coefficients for used standards and for individual methods allows one to choose optimal common standards for methods to be compared. The procedures applied for the same sets of the extracts using identical calibration procedures and common standards allowed better comparison of the results obtained by the TEAC, DPPH, and FRAP methods. The values of content of phenolic substances and total antioxidant activity of the sets of samples correlate very well for all used methods. The very high values of antioxidant activity were found in intensely colored vegetables (red cabbage, red onion, etc.), and the values were very low in watery vegetables such as potato, marrow, and cucumber.
本研究详细探讨了用福林-西奥尔特试剂测定的酚类化合物含量，以及用TEAC（特洛克斯等效抗氧化能力）、DPPH（使用二苯基-对-苦味酰基自由基）和FRAP（铁还原抗氧化能力）方法测定的抗氧化活性，还详细研究了这些方法所使用的标准品（儿茶素、没食子酸、咖啡酸、阿魏酸、特洛克斯、抗坏血酸和硫酸亚铁）与几种常见食用蔬菜提取物之间的相关性。通过比较所用标准品和各方法的吸收系数绝对值，能够为待比较的方法选择最佳通用标准品。对相同提取物采用相同校准程序和通用标准品的操作流程，使得TEAC、DPPH和FRAP方法所得结果的比较更为准确。所有使用的方法中，样品组中酚类物质含量和总抗氧化活性的值都具有很好的相关性。在颜色较深的蔬菜（如紫甘蓝、红洋葱等）中发现了非常高的抗氧化活性值，而在诸如土豆、西葫芦和黄瓜等含水量高的蔬菜中，该值非常低。
