someday manufacturers may have the flavonoid content on their packaging but we aren't quite there yet. basically cocoa powder has the highest amount of phytochemicals followed by bittersweet and then semisweet chocolate. the dark chocolate that has 60% cacao or more on the label is a good sign. you might find out about the specific process used by the chocolate company by checking their website. i personally find dark chocolate very satisfying!
what is the best source for dark chocolate with the highest flavenoid content?