Folin–Ciocalteu reagent

The Folin–Ciocâlteu reagent (FCR) or Folin's phenol reagent or Folin–Denis reagent, is a mixture of

The reagent does not measure only phenols, but will react with any reducing substance. It therefore measures the total reducing capacity of a sample, not just phenolic compounds. This reagent is part of the

This reagent is distinct from Folin's reagent, which is used to detect amines and sulfur-containing compounds.

A 1951 paper entitled "Protein measurement with the Folin phenol reagent"

Because it measures anti-oxidant capacity in vitro, the reagent has been used to assay foods and supplements in food science. The oxygen radical absorbance capacity (ORAC) used to be the industry standard for antioxidant strength of whole foods, juices and food additives.^[7][8] Earlier measurements and ratings by the United States Department of Agriculture were withdrawn in 2012 as biologically irrelevant to human health, referring to an absence of physiological evidence for polyphenols having antioxidant properties in vivo.^[9] Consequently, the ORAC method, derived only from in vitro experiments, is no longer considered relevant to human diets or biology.

The Trolox equivalent antioxidant capacity assay – also based on the presence of polyphenols – is an alternative in vitro measurements of antioxidant capacity.^[10]

See also

• Gallic acid

References