Acid hydrolysis of anthocyanins. First, 5 ml of
2N HCl was added to 1 ml of the purified anthocyanin
solution (3 mg/ml) in a screw-cap test tube,
flushed with nitrogen, and capped. The pigments
were hydrolysed at 100°C for 1.5 h; then, the solution
was immediately cooled in an ice bath (Longo
& Vasapollo 2005). The hydrolysate was purified
using a 500 mg sorbent weight C-18 Sep-Pak
cartridge (Waters) as previously described.
HPLC-PAD analysis and preparation. Highperformance
liquid chromatography (HPLC) was
performed on a Waters RP C18 column (250 ×