Preheat oven to 350°F. Line muffin pan with baking cups. In large bowl, combine cake mix, water, vegetable oil and egg whites; beat with electric mixer 2 minutes. Add orange zest and juice; mix until well blended. Distribute cake mixture evenly into baking cups. Bake 20-22 minutes or until toothpick inserted in center comes out clean. Cool in pan on cooling rack 8 minutes. Remove cupcakes from pan. Cool completely before icing.