Genetically Modified Herbicide-Tolerant Crops and Sugar Beet—Environmental and Health Concerns - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 386

intofructose.Theresultingsyrup(afterenzymeconversion)containsapproximately42%fructose
(HFCS42).Someofthe42%fructoseisthenpuriiedto90%fructose(HFCS90).TomakeHFCS
55, HFCS 90 is mixed with HFCS 42 in appropriate ratios to form the desired HFCS 55. The
enzymeprocessthatchangesthe100%glucosecornsyrupintoHFCS42isasfollows:
1. Cornstarchistreatedwith α -amylasetoproduceoligosaccharides,thatis,shorterchainsofsugars.
2. Glucoamylase,whichisproducedbythe Aspergillus moldinafermentationvat,breaksdownthe
sugarchainsevenfurthertoyieldthesimplesugarglucose.
3. Xylose isomerase (glucose isomerase) converts glucose to a mixture of about 42% fructose and
50%-52%glucosewithsomeothersugarsmixedin.
Whileinexpensiveα-amylaseandglucoamylaseareaddeddirectlytotheslurryandusedonly
once, the more costly xylose-isomerase is packed into columns, and the sugar mixture is then
passedoverit,allowingittobeusedrepeatedlyuntilitlosesitsactivity.This42%-43%fructose-
glucosemixtureisthensubjectedtoaliquidchromatographystep,wherethefructoseisenriched
toabout90%.The90%fructoseisthenback-blendedwith42%fructosetoachievea55%fructose
inalproduct.Mostmanufacturersusecarbonadsorptionforimpurityremoval.Numerousiltration,
ionexchange,andevaporationstepsarealsopartoftheoverallprocess.
12.6.2 pros and Cons of high-Fructose Corn Syrup
HFCSisnotonlysweeterandeasiertoblendintobeveragesthantablesugarbutisalsoagreat
preservative,soitcanbeusedinprocessedfoodstoextendtheirshelflife.HFCSiseasiertotrans-
portandmoreeconomicalincountrieswherethepriceofsugaristwicetheglobalprice,suchasthe
UnitedStatesandCanada.Thesyrupcanbe20%-70%cheaperthansugar.
HFCSisgeneticallymodiied.In1982,whentheartiicialsweetenerwasintroducedintothe
Americanfoodsupply,childrenfortheirsttimebegangettingtypeIIdiabetes,andobesityrates
soared. In at least one study, the syrup has been linked to both. The syrup has also been shown
tointerferewithpeople'smetabolismsothatapersonfeelshungrierthanhe/shereallyis.Thisis
becauseHFCSalsolimitsthesecretionofleptinintothebody'ssystem.Leptinisahormonethat
signalstothebrainwhenyouarefull,andwithoutit,theamountoffoodyouconsumeisnotcon-
trolled.Inparalleltothis,themanufacturedsweeteneralsoencouragestheproductionofghrelin,a
hormoneresponsibleforcontrollingtheappetite,sendingtheappetiteintooverdrive.The American
Journal of Clinical Nutrition in2004publishedastudynotingthattheriseinHFCSconsumption
paralleledtheriseinobesityratesintheU.S.andhypothesizedthatthewayfructoseismetabolized
could be uniquely fattening. The authors later said that their study was meant to inspire further
study,nottobeadeinitivedeclaration.BecausetherearenoenzymestodigestHFCS,itismetabo-
lized by the liver. The pancreas releases insulin the way it normally does for sugar, so fructose
convertstofatmorereadilythananyothersugar.Anoverworkedliverproducessigniicantlymore
uricacid,multiplyingtheriskforheartdisease.Althoughanumberofassociationshaveclaimed
thatHFCSisnotunhealthywhenconsumedinmoderation,itishardtogaugejusthowmuchone
consumes,becausejustlikesugar,itiscontainedinsomanyfoodsonedoesnotknowabout( http://
www.highfructosecornsyrup.org/2009/02/guess-whats-lurking-in-your-food.html ).
A study in 2005, published by Dufault et al. (2009), found trace amounts of mercury within
nineofthe20samplesinvolved,havinglikelyleachedintothesolutionsduringtheprocessoftheir
creation(Dufaultetal.2009).ConcernsregardingthesafetyofHFCSarebeingcontinuallystudied.
TheCornReinersAssociationdisputestheseclaimsandmaintainsthatHFCSiscomparableto
tablesugar( http://www.sweetsurprise.com/ ) .
StudiesbytheAmericanMedicalAssociationsuggest,“ItappearsunlikelythatHFCScontrib-
utesmoretoobesityorotherconditionsthansucrose,”butwelcomefurtherindependentresearch