Meanwhile, drain pineapple juice into 2-cup measuring cup; add remaining 1/2 cup broth to make 1 1/4 cups. In another 2-quart saucepan, mix pineapple liquid, sugar, cornstarch, gingerroot, vinegar and soy sauce. Heat to boiling over high heat. Cook about 2 minutes, stirring constantly. Remove from heat. Stir in bell peppers and pineapple.