2.4. Total phenolic content
Phenolics were measured using the Folin-Ciocalteu's phenol
reagent (Singleton & Rossi, 1965) with modifications. Two hundred
microliters of extract was mixed with 1 mL of Folin-Ciocalteu's
reagent (1 N) and 0.8 mL of 7.5% Na2CO3. The mixture was incubated
at room temperature for 30 min. The absorbance was
measured at 760 nm using a Synergy HT spectrofluorometer (Biotek
Instruments Inc., Winooski, VT, USA). The results are expressed as
mg of gallic acid equivalents (GAE) per gram of extract (dry weight,
dw).