ABSTRACT
Abstract: The beneficial influence of many foodstuffs and beverages including fruits, vegetables, tea, red wine, coffee, and cacao on human health has been recently recognized to originate from the chain-breaking antioxidant activity of natural polyphenols, significant constituent of the above products. Therefore antioxidants have received increasing attention within biological, medical, nutritional, and agrochemical fields and resulted in the requirement of simple, convenient, and reliable antioxidant capacity determination methods. Many methods which differ from each other in terms of reaction mechanisms, oxidant and target/probe species, reaction conditions, and expression of results have been developed and tested in the literature. In this review, the methods most widely used for the determination of antioxidant capacity are evaluated, presenting the general principals, recent applications, and their strengths and limitations. Conclusion: In this review, numerous antioxidant capacity methods, which differ from each other in terms of reaction mechanisms, oxidant and target/probe species, reaction conditions, and expression of results. It is important that analysis conditions, substrate, and concentration of antioxidants should simulate real food or biological systems. The total antioxidant capacity value should include assays applicable to both lipophilic and hydrophilic antioxidants and regards the similarity and differences of both HAT and ET. The assays including various ROS/RNS such as superoxide anion, hydroxyl radical, hydrogen peroxide, singlet oxygen, peroxynitrite, nitric oxide, nitric dioxide have to be designed to comprehensively evaluate the antioxidant capacity of a sample.