Ferric reducing ability of plasma (FRAP, also Ferric ion reducing antioxidant power) is an antioxidant capacity assay that uses Trolox as a standard. The FRAP assay is often used to measure the antioxidant capacity of foods, beverages and nutritional supplements containing polyphenols.
^Benzie, Iris F.F.; Strain, J.J. (1996). "The Ferric Reducing Ability of Plasma (FRAP) as a Measure of "Antioxidant Power": The FRAP Assay". Analytical Biochemistry239 (1): 70–6. doi:10.1006/abio.1996.0292. PMID8660627.