Accessory pigments are light
s such as carotenoid
s and phycobilin
s that serve as complements to chlorophyll
by trapping light energy
Some of these pigments in edible plants act as beneficial antioxidants when consumed by humans and other mammals. Thus, the more brightly-colored a fruit or vegetable is, the better it is likely to be for you.
Part of this writeup is based on work I did for the science dictionary at http://biotech.icmb.utexas.edu/