Total phenolic content of rawand extruded DCFwas determined
according to the Folin-Ciocalteu colorimetric method (Slinkard and
Singleton, 1997). One gram of sample was extracted with 10 mL of
80% (v/v) methanol at room temperature for 2 h. The mixture was
centrifuged at 3000 g for 30 min. 300 mL of the supernatant was
mixed with 1.5 mL of 10% (v/v) Folin-Ciocalteu reagent, vortexed
thoroughly and allowed 5 min for reaction. Then, the mixture was
supplemented with 1.5 mL of (60 g/L) sodium carbonate solution
and incubated at room temperature for 2 h. The absorbance was
measured at 765 nm against the blank containing 80% methanol.
The concentration of total phenolic content in the extracts was
determined as mg of gallic acid equivalent (GAE) per gram of dry
sample using the equation obtained from the standard gallic acid
curve. Total sugar content was measured using the phenol-sulfuric
acid method as described previously. The xylose content of rawand
extruded DCF was determined according to the phloroglucinol
method with xylose as a standard (Douglas, 1981). Glucose content
was measured by using glucose oxidase-peroxidase assay kit
(Megazyme International Ltd., Wicklow, Ireland).