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Folin-Ciocalteu Assay
•
Developed by Folin and Denis 1912 to measure
tyrosine
•
Originally developed as an analysis for protein by
Folin in 1927
WO
4
2‐
/ MO
4
2‐
+ Tyrosine –OH Blue color
•
Folin‐Ciocalteu (1927) added Lithium Sulfate and
Bromine to reaction mixture to prevent precipitate
formation
•
Adopted for phenolics in wine by Singleton 1999
Folin-Ciocalteu Assay
•
PRINCIPAL
•
Reduction of phosphomolybdic phosphotungstic acid (Folin) reagent
‐
to a blue‐colored complex in an alkaline solution occurs in the
presence of phenolic compounds.
•
The Folin ‐Ciocalteu Ciocalteu reagent reagent is not specific specific
and detects all phenolic groups found in extracts including those found
in the extractable proteins.