Application of Sweeteners in Food and Drinks - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 221

bytestingasmallsampleofthesugarsyrupincoldwater,onecandeterminethespeciicconcentra-
tionofthesugarsyrup.
Theseconcentratedsupersaturatedsolutionsareveryunstablebecausethesugarmoleculesare
prone to prematurely recrystallizing as the solution becomes increasingly concentrated. During
heatingofthesolution,agitationshouldnotoccurbecauseitcancauseprematurerecrystallization.
Crystallizationcanbeamajordeterminantofqualityinsugar-basedproducts.Inproducts,such
ashardcandies,theformationofsugarcrystalsisinhibitedduringformationoftheglassystate;
whereas,inproducts,suchasfondants,thepresenceofcrystalsisnecessaryforthedesiredtexture.
Crystallizationofanamorphoussugarmatrixisaffectedbynumerousfactors,includingwater
content,ingredientsoradditives,andenvironmentalconditionsofrelativehumidityandtempera-
ture.Bothadditivesandwatercontentcanaffecttheglasstransitiontemperature(T g )ofaproduct.
T g isadeterminingfactorinthestabilityand,thus,crystallizationofasugarglass(Levensonand
Hartel2005).
Inhardcandies,cornsyruppreventsunwantedcrystallizationorgraining.
LevensonandHartel(2005)madesugarglasseswithamixtureofcornsyrups(ADM,Decatur,
Illinois)andanalytical-gradesucrose(FisherScientiic,Chicago,Illinois).
Eachformulationhada30:70sucrosetocornsyrupratioonadryweightbasis.Themixtures,
withexcesswatertoensuresugardissolution,werecookedoveranopenlametoabout150°Cto
ultimatelyreducethewatercontenttoapproximately3.5%.
The mixtures were cooled into the glassy state in a constant volume in closed-system inside
metalwashers(2.36-mmheightand9.47-mminnerdiameter).
Colorsareusuallyaddedduringboiling.Thesolutionisthencooledandpouredontoanoiled
tablewherelavorsareaddedandkneadedintothemoltenmass.Thewarmandplasticmassisthen
eithermolded,rolled,ormachinedintotheinalform.
Candy types can be dividedintocategories:candies inwhichsugarispresent intheformof
crystalsandcandiesinwhichthesugarispresentinanuncrystallizedform.
Usualdefectsarearesultofsugarsthatcaninvertbecauseofacidaddition(citric,malic,ortar-
taricacid)usuallyusedforlavor.Thiscausesthecandytobehygroscopicandsticky.Vacuumboil-
ingreducedinversionbecauseitoperatesatlowertemperaturesandtime.Crystallizationisanother
alreadymentionedproblemcausedbyincompleteboiling,whenthesucrosetoglucoseratioistoo
high,andifinalmoistureishigherthan1%-2%.Reworkedcandycouldalsocausecrystallization
ascouldhumidstorageconditions.
8.10.1 Crystalline Candies
Crystallinecandiescanbesubdividedintotwogroups:candieswithperceptiblecrystals,such
asrockcandy,andcreamcandiesinwhichcrystalsaretoosmalltobedetectedbythetongue,such
asfondantandfudge.
Rockcandyispreparedsimplybyimmersingastringinasupersaturatedsugarsolution,heating
thesolutiontothehardballstage,andthenallowingittocool.Lefttocool,sugarfromthesolution
willrecrystallizeonthestring.Withnostirringorotherinterferingagents,sugarmoleculeswill
continuetoclump,andthecrystalswillincreaseinsizeaslongasthemassisimmersed.Theresult-
ingproductispuresugarbecauseonlychemicallypuresucrosewillrecrystallize(McGee1984).
Invertedsugarhelpspreventrecrystallization.Invertedsugaristheresultofthebreakdown,
ortheinversion,ofthesucroseintofructoseandglucose.Thisprocesstakesplacewhensucrose
isheatedwithmoistheator,asincandymaking,whenawaterandsugarsolutionisheated.The
amountofwaterusedandthelengthandintensityofthecookingofthesupersaturatedsolution
bothcontrolhowmuchofthesucroseisinverted.Theprocessmaybeacceleratedbyaddedacid
from candy ingredients, such as fruit, brown sugar, molasses, honey, or chocolate (Beranbaum
1985).