TPC in each sample was determined by using the Folin-Ciocalteu
colorimetric method that was previously described (Cai et al., 2004)
with a slight modification. In brief, aliquots (0.1 mL) of appropriately
diluted sample or standard solutions were mixed with 0.5 mL
of 0.5 N Folin–Ciocalteu’s phenol reagent, and the reaction was neutralized
with 1.0 mL of saturated sodium carbonate (75.0 g/L). The
absorbance of the resulting blue color was measured at 760 nm
with a UV–vis spectrophotometer after incubation for 2 h at room
temperature (∼23 ◦C). A calibration curve was prepared using gallic
acidsolution(5–100 g/mL). TPCs were expressedas grams of gallic
acid equivalent (g GAE) per 100 g of dry weight. The determination
was performed in triplicate.