Combine the apple juice concentrate, ginger and garlic. Mix well. Pour mixture into zip top plastic bag...Add the pork cubes. Cover and refrigerate for 30 minutes, turn occasionally to coat.
Spray a 10" no-stick skillet with cooking oil and place over medium-high heat until hot. Add the onions, red peppers and green peppers. Cook, stirring, for 3 minutes, until crisp-tender.
Add the pork and marinade. Cook, stirring, for 5 minutes, until the pork is no longer pink in the center. Insert the tip of a paring knife into 1 cube to test for doneness..
Place the cornstarch, soy sauce and vinegar in a medium bowl. Whisk until smooth. Stir in the pineapple (with juice) and brown sugar. Place mixture into the skillet with the pork and vegetables. Bring to a boil. Cook, stirring frequently, for 3 minutes, or until the sauce thickens. Serve the sweet and sour pork over rice.
Eat now or later: TO FREEZE:, pack the cooled cooked pork in a freezer-quality plastic container. To eat, thaw overnight in the refrigerator. Cover & microwave on high power for 5 minutes, or until hot. Stir half-way through heat cycle.
NOTE: Pork tenderloin may be substituted for pork shoulder. Since tenderloin is much more tender than shoulder. Lightly batter the cubed meat and double deep fry in peanut oil for maximum crispness.