Place apples, pineapple and juice, vinegar, sugar, mustard, water, honey, garlic, cayenne pepper, and onion powder in a large saucepan. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until the apples are tender, about 15 minutes. Allow the mixture to cool to room temperature, then puree in a blender until smooth.
Place the pork chops into a resealable plastic bag, and pour the apple puree overtop. Marinate in the refrigerator overnight.
Preheat an outdoor grill for medium heat, and lightly oil grate.
Remove pork chops from marinade, and shake off excess. Discard remaining marinade.
Cook on preheated grill until the chops are no longer pink in the center, about 5 minutes per side depending on the thickness.
