Determination of total antioxidant capacity by using Aso43-/AsO33- (Arsenate/Arsenite) redox couple

In this study, a two-reagent analysis method was developed to determine the total antioxidant capacities of Çeşme-Pistacia Lentiscus and Yalova-Aronia Melanocarpa plants, which have geographical indications. When the antioxidant molecule is treated with a binary mixture of sodium meta arsenite and sodium molybdate, a yellow or blue color appears as result of the possible redox reaction between them, depending on the structure of the antioxidant molecule. Experiments have shown that flavonoid type (quercetin and epicatechin) and benzoic acid type (gallic acid) antioxidants react with arsenite reagent to form yellow-colored arsenic nanoparticles (AsNP), while vitamins (trolox and ascorbic acid) react with molybdate ions, causing the development of blue color. Thus, differentiation of which types of antioxidants a material can have is achieved by the different affinities of the active groups of antioxidants to the reagents. As a result of the experiments, the highest molar absorptivity was obtained for quercetin. The proposed method was applied to Çeşme-Pistacia Lentiscus and Yalova-Aronia Melanocarpa samples, which recently received geographical indication registration. Total antioxidant capacities (TAC) of the samples were also determined by FRAP (Ferric reducing antioxidant power) and CUPRAC (Cupric Reducing Antioxidant Capacity) methods. TAC values of Çeşme-Pistacia Lentiscus extract and distillate samples and Yalova-Aronia Melanocarpa fruit juice were determined as 10.78 g GAEAC/kg, 10.22 mg GAEAC/L and 0.32 g GAEAC/kg, respectively.