California Barbecue Sauce II

In a medium noncorrodible saucepan, combine 1 cup of the fruit juice, the brown sugar, ketchup and vinegar. Bring to a boil over moderate heat, stirring occasionally. In a small bowl, dissolve the cornstarch in the remaining 1/2 cup juice. Whisk into the hot sauce, and simmer, stirring constantly, until the sauce is thickened and slightly translucent, about 3 minutes.