Cooked rice, optional Drain pineapple, reserving half cup juice. Place pineapple chunks and vegetables in a large bowl; set aside. In a sauce pan, combine reserved pineapple juice with soy sauce, olive oil, brown sugar and seasonings; bring to a boil. Reduce heat and simmer, uncovered, for 5 minutes. Pour over vegetable mixture; cover and refrigerate for at least 1 hour, stirring occasionally. Remove pineapple and vegetables from marinade and reserve marinade. Alternate pineapple, green pepper, onion if desired, mushrooms and tomatoes on skewers. Grill kabobs for 20 minutes or until soft, turning and basting with marinade frequently. Serve over rice if desired.