Syrups - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 152

whereasintheEuropeanCommission,potatostarchandsoftwheatstarch(gradeA)areusedina
smallamount(approximately10%)ofthetotalproduction(Schenck2006).
TheclassiicationofglucoseandfructosesyrupisbasedonDE,whichistheamountofreducing
sugars(dextrose)inthesyrupandexpressedasapercentageofthedrytotalsolids(Schenck2006).
Forexample,syrupsareclassiiedastypesI-IV,dependingontheirDE:

• TypeI:DE20-38

• TypeII:DE39-58

• TypeIII:DE59-73

• TypeIV:DE>74

Aseparateclassiiedsyrupgroupisthehigh-fructosesyrup,whichcanbeextendedtoinclude
high-maltosesyrupswithawidevariationoffructoseandmaltoseandDEvaluessimilartocon-
ventionalsyrup.

6.2.3 Glucose Syrup production

Productionmethodologyforglucosesyrupderivedfromcornstarchhasbeenavailableformore
than100yearssincethemid-nineteenthcentury.Glucosesyrupprocessinghassincemovedtoward
highlyautomatedcontinuousprocessesthroughnewenzymesystemsproducingavarietyofsyrups
forthefoodandbeverageindustries(Melansonetal.2007).
Thebasicstepsofglucosesyrupproductionare(1)conversion,(2)puriication,and(3)concen-
tration.Thestarchhydrolysisdeinesthetypeofsyrupproduced.
Starchisdeinedasachemicalcompound,i.e.,aglycan,thatcontainstwoglucosepolymers:
amylaseandamylopectinmolecules.Thedifferentrelativeproportionsofthesecomponentsinvari-
ousstarchesarenotrelevantforglucosesyrupproduction,buttheydohavesomeminordifferences
intheconversionandthepuriicationsteps(Schenck2006).
Conversionistheprocessingstepduringwhichstarchishydrolyzedwithacid-enzymeaidto
resultinlowermolecularweightproducts(glucosesyrups).Thesystemsusedintheconversionpro-
cessareacid,acid-enzyme,andenzyme-enzyme.Intheprocessingstepsfortheirsttwoconver-
sionsystems,starchslurryisacidiiedandhydrolyzedwithacidoracid-enzymeaidandheatedin
converters.Then,theliquorsarecooled,neutralized,andpuriiedtoremoveimpurities(suspended
proteinsandlipids)beforetheirconcentrationtoadeterminedsolidlevel.Thepuriication(discolor-
ation)stepisperformedusingcarbontreatment,andthedegreeofconversioniscontrolledbyacid,
temperature,andreactiontime.
Syrup types with DE values of 20-55 are usually acid-converted starches made into regular
glucose syrups. Other types with lower DE values are considered maltodextrins, and those with
DEvalueshigherthan55arebitterby-products.However,asecondaryenzymeconversionstageis
requiredforsyruptypeswithhigherDEvaluesofupto94.Thesolidcontentofglucosesyrupvaries
from70%to83%accordingtoproducttypeandmarketrequest.
Intheprocesslowofenzyme-enzymeconvertedsyrup,thealphaamylaseisusedasahydrolyz-
ingagent,andthekindofsyrup(e.g.,high-maltose,dextrose,orfructose)tobeproduceddependson
thesubstrate.Forexample,forhigh-dextrosesyrup,anamyloglucosidaseenzyme,combinedoften
withpullulanase,isusedtoproducealevelofmorethan95%dextroseproduct.
Afterpuriicationanddemineralization,animmobilizedenzymesystemiscommonlyusedto
producea42%fructosesyrup,which,byenrichmentthroughachromatographicprocess,canlead
toveryhighfructose(>90%)syrup.However,avarietyofsyrupblendscanbeobtainedbymixing
differentfructoseandglucosesyrup.
Glucosesyruppossessesfunctionalpropertiesaccordingtoconversiondegree,sugarcomposi-
tion,andprocessingsystem,asshowninTable6.1.Theviscosityofglucosesyrupisinluencedby