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. Antioxidants are substances with antioxidative properties. They are most commonly present in fruits and vegetables. In addittion, other foods such as wine, meat or eggs contain these substances.
Bioquochem ABTS assay kit is recommended for total antioxidant activity of solutions of pure substances, aqueous mixtures and beverages.
ABTS Antioxidant Capacity
The assay described here involves the direct production of the blue/green ABTS•+ chromophore, which has absorption maxima at 734 nm. After that, the addition of antioxidants to the pre-formed radical cation, reduces ABTS depending on the antioxidant activity and the concentration of the antioxidant. Particularly, in our assay, a solution of ABTS at neutral pH, 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. Then, antioxidant compounds present in the sample quench the color and produce a decoloration of the solution which is proportional to their amount. This reaction is rapid and the end point, which is stable, corresponds to a measure of the antioxidative efficiency.
ABTS (uncolored) + Reagent → ABTS•+(blue/green) (λmáx= 734 nm)
ABTS•+(blue/green) + AOH → ABTS (uncolored) +AO
Scheme 1. Formation of radical ABTS and its reaction with antioxidants (AOH)