title: Antioxidant Activity/Capacity Measurement. 1. Classification, Physicochemical Principles, Mechanisms, and Electron Transfer (ET)-Based Assays.
abstract: Because there is no widely adopted "total antioxidant parameter" as a nutritional index for labeling food and biological fluids, it is desirable to establish and standardize methods that can measure the total antioxidant capacity (TAC) level directly from plant-based food extracts and biological fluids. In this review, we (i) present and classify the widely used analytical approaches (e.g., in vitro and in vivo, enzymatic and nonenzymatic, electron transfer (ET)- and hydrogen atom transfer (HAT)-based, direct and indirect assays) for evaluating antioxidant capacity/activity; (ii) discuss total antioxidant capacity/activity assays in terms of chemical kinetics and thermodynamics, reaction mechanisms, and analytical performance characteristics, together with advantages and drawbacks; and (iii) critically evaluate ET-based methods for analytical, food chemical, biomedical/clinical, and environmental scientific communities so that they can effectively use these assays in the correct places to meet their needs.
authors.affiliation: Department of Chemistry, Faculty of Engineering, Istanbul University , Avcilar, 34320 Istanbul, Turkey.
authors.forename: Reşat
authors.initials: R
authors.lastname: Apak
authors.affiliation: Department of Chemistry, Faculty of Engineering, Istanbul University , Avcilar, 34320 Istanbul, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Özyürek
authors.affiliation: Department of Chemistry, Faculty of Engineering, Istanbul University , Avcilar, 34320 Istanbul, Turkey.
authors.forename: Kubilay
authors.initials: K
authors.lastname: Güçlü
authors.affiliation: Department of Food Engineering, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University , Maslak, 34469 Istanbul, Turkey.
authors.forename: Esra
authors.initials: E
authors.lastname: Çapanoğlu
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000145:classification; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D004579:Electron Transport; D010084:Oxidation-Reduction
chemical_list: D000975:Antioxidants
keywords: antioxidant activity; antioxidant mechanisms; electron transfer-based assays; food analytical methods; total antioxidant capacity