Preheat oven to 400°.
Combine first 6 ingredients in a medium bowl; make a well in center of mixture. Combine oil, rind, juice, yogurt, and egg; stir well. Add to dry ingredients, stirring just until moist.
Spoon batter into each of 12 muffin cups coated with cooking spray.
Bake at 400° for 14 minutes or until golden. Remove muffins from pan immediately; place on a wire rack.