Preheat oven to 350°.
Lightly spoon flours into dry measuring cups, and level with a knife. Combine flours and the next 4 ingredients (flours through salt) in a large bowl, and make a well in center of mixture. Combine milk, butter, rind, and egg; add to flour mixture, stirring just until moist. Spoon batter into an 8 x 4-inch loaf pan coated with cooking spray.
Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool 5 minutes in pan on a wire rack, and remove from pan. Cool completely on wire rack. Combine the powdered sugar and orange juice; drizzle over bread.