Chiffon cakes are similar to a foam cake because the mechanical leavening agent used is beaten egg whites. In addition to the egg whites, the yolks are used too. Unlike foam cakes, oil is used as a fat in this cake. chiffon cakes utilize both the mechanical leavening agent of egg whites but also a chemical leavening agent of baking powder.
Chiffon cake is a very moist cake because of the high egg and oil content. Because of this, the cake does not tend to dry out or harden like traditional cakes