You're probably more likely to find pinto beans on a cheap plate of food, rather than a foodie's plate. But the foodie really should reconsider, because pinto beans have antioxidants and a lot of them.
ORAC Source
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010