In a 12-inch skillet over medium heat, in hot butter, cook cranberries, chopped walnuts, and cinnamon about 10 minutes or until cranberries pop, stirring mixture frequently. Remove skillet from heat.
In large bowl, stir together orange and lemon peels and juice, mashed banana, brown sugar, sugar, egg whites, and egg.
Preheat oven to 350*F (175*C). Grease two 9 x 5 x 3-inch loaf pans.
In medium bowl, stir together all-purpose flour, whole-wheat flour, baking powder, baking soda, and salt; add to egg mixture, stirring to blend. Fold in cranberry mixture just until mixed.
Spoon into prepared pans and bake for 50 minutes to 1 hour, or until wooden pick inserted in center comes out clean. Let stand for 10 minutes before removing from pan. Cool on wire rack. Wrap tightly to store.