The aqueous extract obtained from
each of the three extraction methods was adjusted to pH 3.0 with
phosphoric acid, to which AC at 40 g/L was added, and
magnetically stirred for 30 min at 60 8C, under dark. After cooling
at room temperature, the mix was vacuum filtered through celite
(1 cm). CGA were desorbed from AC using ethanol 96% (v/v), then
dried with anhydrous sodium sulphate, and finally dried in a rotary
evaporator at 60 8C and 120 rpm. The residue was analyzed by TLC
and by HPLC.