Mosca L, De Marco C, Visioli F, Cannella C
Department of Biochemical Sciences and Institute of Food Science and Nutrition, University of Rome "La Sapienza", p.le Aldo Moro 5, 00185 Rome, Italy.
J Agric Food Chem. 2000 Feb;48(2):297-301. doi: 10.1021/jf990556+.
A new spectrophotometric assay for the determination of the polyphenolic content of olive oil is presented. It is a substrate-recycling assay for phenolic compounds that employs tyrosinase in the presence of excess NADH. The reaction of various phenols with the enzyme produces an o-quinone, which is detected by recycling between reactions with the enzyme and NADH. The method offers some advantages over the classical methods employed to determine the polyphenolic content of olive oil, that is, ease and reproducibility of the analysis, highly increased sensitivity, and selectivity toward phenolic compounds. The amount of total polyphenols was determined in virgin olive oils both with the Folin-Ciocalteu reagent and with the proposed enzymatic method. The results suggest a better estimation of the polyphenol content, as compared with the colorimetric method. This has to be attributed to the different reactivities of the two methods toward phenols and catechols. Finally, the enzymatic method demonstrates that there is a linear relationship between the olive oil phenolic content and the antioxidative capacity of oil extracts.
本文介绍了一种用于测定橄榄油中多酚含量的新分光光度法。它是一种针对酚类化合物的底物循环测定法，在过量烟酰胺腺嘌呤二核苷酸（NADH）存在的情况下使用酪氨酸酶。各种酚与该酶的反应会产生邻醌，通过在酶与NADH的反应之间循环来检测邻醌。该方法相对于用于测定橄榄油中多酚含量的经典方法具有一些优势，即分析简便且可重复、灵敏度大幅提高以及对酚类化合物具有选择性。使用福林 - 西奥尔特试剂和所提出的酶法测定了初榨橄榄油中的总多酚含量。结果表明，与比色法相比，该方法能更好地估算多酚含量。这归因于两种方法对酚类和儿茶酚的反应性不同。最后，酶法表明橄榄油中的酚含量与油提取物的抗氧化能力之间存在线性关系。
