“We found that the oxidation of cyanidin with hydrogen peroxide , tert-butyl hydroperoxide, 2,2'-azobis(2-methylpropionamidine), 3-morpholinosydnonimine hydrochloride, sodium hypochlorite, Fe3+, and Fe2+ induced the appearance of a new fluorescence band, centered at 525-540 nm when excited at 470-490 nm.”