Melt butter in a large Dutch oven over medium-low heat. Add apple, onion, and garlic to pan. Cover and cook 12 minutes or until onion is tender. Add curry powder, salt, and red pepper to pan. Combine milk and cornstarch in a small bowl, stirring with a whisk; add to pan. Stir in broth. Reduce heat, and cook 4 minutes or until slightly thickened, stirring constantly. Add turkey and juice to pan; cook 5 minutes or until turkey is thoroughly heated.