2.5. Analysis of total phenolic compounds in cookies
The total phenolic content was determined by the FolinCiocalteu assay as described by Singleton, Orthofer, and LamuelaRaventos (1999) and expressed as mg of gallic acid equivalent
(GAE) per kg of dry matter (d.m.). One hundred mL of the extract
was transferred into test tubes and their volume made up to 500 mL
with distilled water. After addition of Folin-Ciocalteu reagent (250 mL) and 20 g/100 g aqueous Na2CO3 solution (1.25 mL), tubes
were vortexed. The absorbance of the mixture was measured at
750 nm after 40 min.