ABTS Antioxidant Capacity Assay
Antioxidant capacity is an overall ability of organisms or food to catch free radicals and prevent their harmful effect. Antioxidative effect includes protection of cells and cellular structures against harmful effect of free radicals, especially oxygen and nitrogen. Substances with antioxidative properties are called antioxidants.
ABTS assay kit is recommended for total antioxidant activity of solutions of pure substances, aqueous mixtures and beverages. The assay described here involves the direct production of the blue/green ABTS•+ chromophore. This has absorption maxima at 734 nm. The addition of antioxidants to the pre-formed radical cation, reduces it ABTS depending on the antioxidant activity and the concentration of the antioxidant.
In our assay a solution of ABTS at neutral pH and in the presence of a suitable solution, can form a stable and colored radical cation (ABTS•+) which shows a maximum of absorbance at 734 nm. Antioxidant compounds quench the color and produce a decoloration of the solution which is proportional to their amount. This reaction is rapid and the end, which is stable, is taken as a measure of the antioxidative efficiency.
ABTS (uncolored) + Reagent → ABTS• + (blue/green)
(λmax= 734 nm) ABTS• + (blue/green) + AOH → ABTS (uncolored) + AO