Cut each orange, including the rind, into 8 sections. Remove and discard seeds. Chop orange fine in a food processor, blender or grinder. Set aside in a 2 quart bowl. Repeat chopping with cored and cut apples, peeled if desired. Combine apples with oranges. Peel bananas, puree or mash and mix with other fruits. Beat eggs in a large mixer bowl. Add sugar gradually, beating until mixture is thick and smooth. Beat in butter. Add fruits. In a 1 quart container, stir or shake flour with baking powder and baking soda. Beat flour mixture into fruit mixture. Stir in raisins and walnuts. Nut pieces should be small enough not to interfere with slicing. Turn batter into 2 (9 x 5 x 3 inch) loaf pans that have been greased and floured. Bake at 350ºF. for 1 hour or until cake tests done. Let cool on rack before slicing. Serve plain or topped with a glaze of confectioners' sugar and orange juice. Makes 2 loaves 10 to 12 servings each.