Coat large roasting pan with nonstick cooking spray.
In small bowl, combine lemon peel, cinnamon, ginger, allspice, and nutmeg.
In another small bowl, combine oil and half of the spice mixture. Season pork with salt and pepper, and rub with the oil mixture. Place in prepared roasting pan.
In large bowl, toss apple and onion wedges with lemon juice and remaining spice mixture. Place in the prepared roasting pan with pork and 1/4 cup water.
Roast, tossing the apple and onions once, 50 minutes, or until a thermometer inserted into the thickest portion registers 155°F and juices run clear. Remove from oven and allow to stand for 10 minutes.
Meanwhile, in medium saucepan, bring apple juice and SPLENDA® Granulated No Calorie Sweetener to boil. Reduce heat and simmer 1-2 minutes. Remove from heat.
In food processor fitted with metal blade, purée 2/3 of apple mixture with pan liquids until smooth. Add to juice mixture. Season to taste with salt and pepper, if desired. Cook on medium-low heat until warm.
Cut pork into thin slices. Garnish with remaining cooked apple and onion wedges. Serve with sauce on side.