31 No. 4
Methods of Measurement and Evaluation of Natural Antioxidant Capacity/Activity
The chemical diversity of natural antioxidants makes it difficult to separate, detect and quantify individual antioxidants from the complex matrix. Moreover, the total antioxidant power is often more meaningful to evaluate health beneficial effects because of the cooperative action of individual antioxidant species. Currently there is no single antioxidant assay for food labeling because of the lack of standard quantification methods.
Antioxidant assays may be broadly classified as the electron transfer (ET)- and hydrogen atom transfer (HAT)-based assays. The results obtained are usually hardly comparable because of the different mechanisms, redox potentials, pH- and solvent-dependencies, etc., in various assays.
This project will help identify and quantify properties and mutual effects of antioxidants, to bring a more rational basis to the classification of antioxidants and antioxidant assays and to make the results more comparable and understandable. This project will bring in terms of definitions or definition-like characterization and classification of the chemical and biochemical methods of antioxidant assays as well as related antioxidant chemistry and provide analytical, food chemical, biomedical/clinical, and environmental communities with critical evaluation on this topic.
The task group members are experienced in various methods of antioxidants assay. The chairperson has developed a novel CUPRAC (cupric reducing antioxidant capacity) method1 which has been successfully applied to antioxidants assay in food plants, human serum, and to hydroxyl radical scavengers.2
1. R. Apak, K. Güçlü, M. Özyürek, S. E. Karademir, J. Agric. Food Chem. 52 (2004) 7970-7981. doi:10.1021/jf048741x
2. M. Özyürek, B. Bektaþoðlu, K. Güçlü, R. Apak, Anal. Chim. Acta, 616 (2008) 196-206. doi:10.1016/j.aca.2008.04.033
For more information and comments, contact Task Group Chair Resat Apak
last modified 1 July 2009.
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