Preheat oven to 180c. Peel sweet potatoes; core apples. Cut potatoes, apples and orange crosswise into 2cm thick slices. Arrange in a foil-lined baking pan coated with cooking spray; sprinkle with salt and pepper. Roast 10 minutes.
Meanwhile, in a microwave-safe bowl, mix orange juice, brown sugar, corn flour, cinnamon and ginger. Microwave, covered, on high, stirring every 30 seconds until thickened, 1-2 minutes. Stir until smooth.
Place pork over sweet potato mixture; drizzle with orange juice mixture. Roast until cooked to your liking and sweet potatoes and apples are tender, around 45-55 minutes.
Remove from oven; tent with foil. Let stand 10 minutes before slicing.