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

Manufacturersalsofillshorteningswith
preformedbubblesofnitrogen(around10%
ofthevolume),andbubble-stabilizing
emulsifiers(upto3%oftheshortening
weight).Butterisbestaeratedatarelatively
cool65ºF/18ºC,whileshorteningcreamsmost
effectivelyatawarmroomtemperature,
between75and80ºF/24–27ºC.
FatReplacersThemoisteningandtenderizing
effects of fat — but not its aerating abilities
—canbeimitatedbysomeconcentratedfruit
purees, notably prune, apple, apricot, and
pear. Their high levels of viscous plant
carbohydrates,
mainly
pectins
and
hemicelluloses, bind water and also interrupt
theglutenandstarchnetworks.Sothesefruit
pureescanbeusedtoreplacesomeofthefat
in cake recipes. The result is usually moist
and tender, but also denser than a full-fat
cake.
TechniquesforAeratingCakes


Fat-sugaraeration:Sugarbeateninto
butterorshortening;otheringredients
thenfoldedin
Pound cake, Frenchquatre quarts,
Americanbutterandlayercakes,fruitcake

Egg-sugaraeration:Sugarbeatenwith
wholeeggs,orseparatedyolksorwhites;
otheringredientsthenfoldedin
Wholeeggs:Génoise
Yolks and whites aerated separately:
Frenchbiscuit,BlackForestcake
Yolksonly:Spongecake
Whites only: Angel food cake; chiffon
cake;flourlessmeringueanddacquoise
All-ingredientsaeration:Flour,eggs,
sugar,shorteningallbeatentogether
Commercialcakemixes