An aliquot (6 mL) of the aqueous phase was carefully
deposited onto a C18 Sep-Pak Vac 3 cc cartridge (Waters); the
anthocyanins and other phenolic compounds were absorbed to the
column, whereas the sugars and more polar substances were
eluted with 10 mL of acidified water (0.1% formic acid). The
anthocyanins were then recovered with 5.0 mL of acidified
methanol containing 0.1% formic acid, and the methanolic extract
was concentrated under vacuum in a rotary evaporator at 30 8C.