On food and cooking the science and lore of the kitchen ( PDFDrive ) 1055

Manufacturers also fill shortenings with preformed bubbles of nitrogen (around 10% of the volume), and bubble-stabilizing emulsifiers (up to 3% of the shortening weight) Butter is best aerated at a relatively cool 65ºF/18ºC, while shortening creams most effectively at a warm room temperature, between 75 and 80ºF/24–27ºC Fat Replacers The moistening and tenderizing effects of fat — but not its aerating abilities — can be imitated by some concentrated fruit purees, notably prune, apple, apricot, and pear Their high levels of viscous plant carbohydrates, mainly pectins and hemicelluloses, bind water and also interrupt the gluten and starch networks So these fruit purees can be used to replace some of the fat in cake recipes The result is usually moist and tender, but also denser than a full-fat cake Techniques for Aerating Cakes Fat-sugar aeration: Sugar beaten into butter or shortening; other ingredients then folded in Pound cake, French quatre quarts, American butter and layer cakes, fruit cake Egg-sugar aeration: Sugar beaten with whole eggs, or separated yolks or whites; other ingredients then folded in Whole eggs: Génoise Yolks and whites aerated separately: French biscuit, Black Forest cake Yolks only: Sponge cake Whites only: Angel food cake; chiffon cake; flourless meringue and dacquoise All-ingredients aeration: Flour, eggs, sugar, shortening all beaten together Commercial cake mixes ... whole eggs, or separated yolks or whites; other ingredients then folded in Whole eggs: Génoise Yolks and whites aerated separately: French biscuit, Black Forest cake Yolks only: Sponge cake Whites only: Angel food cake; chiffon cake; flourless meringue and dacquoise...Fat-sugar aeration: Sugar beaten into butter or shortening; other ingredients then folded in Pound cake, French quatre quarts, American butter and layer cakes, fruit cake Egg-sugar aeration: Sugar beaten with... only: Angel food cake; chiffon cake; flourless meringue and dacquoise All-ingredients aeration: Flour, eggs, sugar, shortening all beaten together Commercial cake mixes