2.3. Chemical analysis
Solvents of HPLC-gradient grade and all other chemicals of analyticalreagent
grade were purchased from Sigma (Milan, Italy). The solutions
were prepared in deionized water produced by a Purelab Classic system
(Elga Labwater, Marlow, UK). Anthocyanin standards (delphinidin-3-Oglucoside
chloride, malvidin-3-O-glucoside chloride, petunidin chloride,
peonidin-3-O-glucoside chloride and cyanidin-3-O-glucoside chloride)
were supplied from Extrasynthèse (Genay, France).