Assessment of the TEAC method for determining the antioxidant capacity of synthetic red food colorants

The TEAC method was used to evaluate the antioxidant capacity of six synthetic red food colorants (azorubine, amaranth, ponceau 4R, erythrosine, red 2G and allura red AC). This method assesses the ability of such compounds to scavenge the stable radical cation chromophore ABTS(+.), comparing it with that of Trolox, a water soluble vitamin E analogue. It is simple, fast (6 min) and, at the wavelength used for measurements (735 nm) does not interfere with the absorption maxima of the colorants. The experiments showed an antioxidant ranking of allura red AC > azorubine > amaranth > red 2G > erythrosine > ponceau 4R. Their corresponding TEAC values were 0.029, 0.026, 0.019, 0.018, 0.016 and 0.007, respectively. (c) 2005 Elsevier Ltd. All rights reserved.