On food and cooking the science and lore of the kitchen ( PDFDrive ) 1240
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crystals.Thistendencytoformcrystalsisthe
meansbywhichweobtainpuresugarfrom
plantjuices,andit’sthewaythatwemake
manykindsofcandies.Sugarcrystallization
isdescribedindetailonp.682.
Caramelization
Caramelizationisthenamegiventothe
chemicalreactionsthatoccurwhenanysugar
isheatedtothepointthatitsmoleculesbegin
tobreakapart.Thisdestructiontriggersa
remarkablecascadeofchemicalcreation.
Fromasinglekindofmoleculeintheformof
colorless,odorless,simplysweetcrystals,the
cookgenerateshundredsofnewanddifferent
compounds,someofthemsmallfragments
thataresourorbitter,orintenselyaromatic,
otherslargeaggregateswithnoflavorbuta
deepbrowncolor.Themorethesugaris
cooked,thelesssugarandsweetnessremain,
andthedarkerandmorebitteritgets.
Thoughcaramelismostoftenmadewith
tablesugar,itssucrosemoleculesactually
breakapartintotheirglucoseandfructose
componentsbeforetheybegintofragmentand
recombineintonewmolecules.Glucoseand
fructoseare“reducingsugars,”meaningthat
theyhavereactiveatomsthatperformthe
oppositeofoxidation(theydonateelectronsto
othermolecules).Asucrosemoleculeismade
fromoneglucoseandonefructosejoinedby
theirreducingatoms,sosucrosehasno
reducingatomsfreetoreactwithother
molecules,andisthereforelessreactivethan
glucoseandfructose.Thisiswhysucrose
requiresahighertemperaturefor
caramelization(340ºF/170ºC)thanglucose
(300ºF/150ºC)andespeciallyfructose
(220ºF/105ºC).
