In a large resealable plastic bag, combine the apple juice, soy sauce, oil, lemon juice, onion, vanilla, ginger, garlic powder and pepper; add the turkey. Seal bag and turn to coat. Refrigerate for at least 2 hours. , Drain and discard marinade. Grill turkey, covered, over medium heat for 8-10 minutes on each side or until a thermometer reads 170°.