On food and cooking the science and lore of the kitchen ( PDFDrive ) 201
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andmakeitlessrunny,andthusallowthe
bubblestosurvivelongenoughtoaccumulate
intoasizeablemass.Whatgivesthemassof
foamausefulkitchenlifetimeisthewhite’s
teamofproteins.
HowtheEggProteins
StabilizeFoams
StressBuildsProteinSolidarityAsistrue
forthesettingofheatedeggsandcustards,the
keytothestableeggfoamisthetendencyof
theproteinstounfoldandbondtoeachother
whenthey’resubjectedtophysicalstress.Ina
foamthiscreatesakindofreinforcementfor
thebubblewalls,theculinaryequivalentof
quick-settingcement.Whippingexertstwo
kindsofphysicalstressontheproteins.First,
asweforcethewhiskthroughthewhite,the
whiskwiresdragsomeoftheliquidwith
them,andcreateapullingforcethatunfolds
thecompactedproteinmolecules.Andsecond,
becausewaterandairareverydifferent
physicalenvironments,thesimplemixingof
airintothewhitescreatesanimbalanceof
forcesthatalsotugstheproteinsoutoftheir
usualfoldedshape.Alltheseunfolded
proteins(mainlytheglobulinsand
ovotransferrin)tendtogatherwhereairand
watermeet,withtheirwater-lovingportions
immersedintheliquidandtheirwateravoidingportionsprojectingintotheair.Thus
disturbedandconcentrated,theyreadilyform
bondswitheachother.Soacontinuous,solid
networkofproteinspervadesthebubblewalls,
holdingbothwaterandairinplace.
EarlyEgg-WhiteFoams:“Snow”and
Biscuits
HowtoBreakWhitesofEggsSpeedily
Afigortwoshredinpiecesandthen
beatenamongstthewhitesofeggswill
bringthemintoanoilspeedily:somebreak
themwithastubbedrod,andsomeby
