2.5. Determination of total phenolic contents
The filtrates obtained from each extraction were freeze dried
(Savant, Vapornet VN 100, Labequip Ltd., Markham, Ontario, Canada)
and stored at−20 °C until further analysis. Total phenolic contents of
the extracts were analyzed by the method of Singleton and Rossi
(1965)and then expressed as gallic acid equivalents (GAE)/g. The
total phenolic content was determined using a standard gallic acid
calibration curve