Between raw, fresh red grapes vs. grape juice, which has more antioxidants? As is the case with all juice production, nutrients are lost in the process, primarily due to the heat from pasteurization which destroys vitamin C (this is why ascorbic acid is typically added back in afterward). But even when you take this into account, grape juice has almost the exact same ORAC value as the fruit fruit does. Presumably, this is because even though antioxidant content is lost in production, the fact that the juiced version is more concentrated with less water (when compared to the fresh fruit) helps to offset the loss.
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