Cake flour

Special cake flour with a high starch-to-gluten ratio is made from fine-textured, soft, low-protein wheat. It is strongly bleached, and compared to all-purpose flour, cake flour tends to result in cakes with a lighter, less dense texture.^[1] Therefore, it is frequently specified or preferred in cakes meant to be soft, light, and or bright white, such as angel food cake. However, cake flour is generally not considered mandatory for good results, and its effect on the cake's texture can readily be simulated by adding corn starch and/or baking soda to all-purpose flour.^{[2][3][4][5][6]} Some recipes explicitly specify or permit all-purpose flour,^[7][8] notably where a firmer or denser cake texture is desired.





http://en.wikipedia.org/wiki/Cake