Heat oil in large nonstick skillet over medium-high heat until hot. Add pork; cook until no longer pink and browned on each side. Remove pork from skillet; cover to keep warm. Drain drippings from skillet.
In small bowl, combine apple juice, mustard, cornstarch, brown sugar, salt and pepper; blend well. Add cornstarch mixture and sweet potato to skillet. Cover; cook over medium heat for 10 to 15 minutes or until sweet potato is crisp-tender, stirring occasionally.
Stir in apple, bell pepper and pork. Cover; cook an additional 5 minutes or until bell pepper is crisp-tender, stirring occasionally. If desired, serve with hot cooked rice sprinkled with chopped fresh parsley.