The food lab better home cooking through science ( PDFDrive ) 998

smallbitsoffatwillrefractlighttoamuchgreaterthanabig
pool of fat, which is what gives mayonnaise its opaquewhite appearance.Think of it like the windshield of a car.
Whenit’swhole,lightpassesthroughiteasily.Butgetafew
cracksinit,anditbecomesdifficulttoseethrough.Crackit
enough times into small enough pieces, and it becomes
opaque.Samethingwiththefatinmayonnaise.
Normally when you mix fat molecules with water, no
matterhowthoroughlyyoucombinethem,likeMITnerdsat
an all-girls-college mixer, they eventually separate
themselves and regroup. Because of their shape and
electrical charges, fat molecules are mutually attracted to
each other while simultaneously being repelled by water.
This is where egg yolks come in. Egg yolks—which are
complex fat and water emulsions in themselves—contain
plentyofemulsifiers(agentsthataidingettingfatandwater
to behave), the most important of which is lecithin, a
phospholipid found in both the low-density lipoproteins
(LDLs) and high density lipoproteins (HDLs) abundant in
eggs.Emulsifiersarelongmoleculesthathaveahydrophilic
(water-loving, fat-hating) head, and a hydrophobic (waterhating,fat-loving)tail.


Settingyourmixingbowlontopofatowel-linedpotwill
stabilizeitduringheavywhisking.
Wheneggyolks,water,andoilarewhiskedtogether,the
fat-loving heads of the lecithin molecules bury themselves
in the minute droplets of fat, leaving only their tails
exposed.These tails repulse each other, preventing the fat
droplets from coalescing and suddenly making the water
seemmuchmoreattractivetothem—abitlikeaddingafew
kegs of beer to that nerd fest to mix things up a little.To

makeatraditionalmayonnaise,eggyolks,water,salt,anda
few flavorings—usually Dijon mustard and lemon juice or
vinegar—are whisked together vigorously while the oil is
simultaneously slowly drizzled into the mixture (a food