Chemistry Reference
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than PCA as a means for variable selection. The best classiication models were achieved with
LS-SVM.Atotalaccuracyof95.1%andtheareaunderthereceiveroperatingcharacteristiccurves
of 0.952 for a test set were obtained by LS-SVM. The results showed that WT-LS-SVM can be
usedasarapidscreeningtechniqueforthedetectionofthistypeofhoneyadulterationwithgood
accuracyandbettergeneralization.
NIRS coupled with appropriate chemometric methods seems to be an eficient and rapid
technique to discriminate between authentic honeys and honeys adulterated by fructose-glucose
mixtures.
9.21 rOLe OF VISCOSItY aND teXtUre IN SWeetNeSS
Mostoftheexperimentaldataavailableabouttheinluenceofviscosityonsweetnessdealwith
sweetenersolutionsthickenedwithdifferenthydrocolloids.Generally,inthesesolutions,increasing
viscosityleadstoadecreaseinsweetness(Cooketal.2002),althoughsomeauthorshavereported
theoppositeeffect:insomecases,increasingviscositymayenhancesweetness(Kanemaru,Harada,
andKasahara2002).
Thebigdifferencesinthecomposition,structure,andrheologicalbehaviorofthediversityof
foodmatricesandthewell-knownvariationsinthemasticationprocessamongindividualsmakethe
interpretationoftheperceiveddifferencesinsweetnesshighlydificult(WilsonandBrown1997).
In gelled systems (food or model) sweetened with one compound at a certain concentration, the
higherthehydrocolloidconcentration,thelowerthesweetnessintensity(WilsonandBrown1997;
Costell,Durlan,andPeyrolon2000).
Morris(1995)hasconcludedthatthesensoryresponsealsodependedonsometexturalcharac-
teristics,suchasbreakingstrainorbrittleness.Othergelcharacteristics,suchaselasticity,cohesive-
ness,ormeltingpoint,mayalsoplayarole(Clark2002).
Bayarri,Duran,andCostell(2003)analyzedtheinluenceofthetypeandconcentrationoftwo
hydrocolloids,k-carrageenanandgellangum,andtwosweeteners,sucroseandaspartame,onthe
gelresistancetocompression,sweetenerdiffusion,andintensityofthegelsweetnessandstudied
therelationshipsbetweenthegels'physicalpropertiesandtheirperceivedsweetness.
Theadditionofsucroseproducedabiggerincreaseingelstrengthatthehigherhydrocolloidconcen-
tration.Themaineffectdetectedonthesweeteners'diffusionconstantwasthehighervalueobservedin
lowconcentration(3gL
−1
)k-carrageenangels.Gellangelswereperceivedsweeterthank-carrageenan
gels. Variations in sweetener concentration, true rupture strain, and deformability modulus values
explained93%ofthevariabilityinsweetnessforgelswithsucroseand94%forgelswithaspartame.
9.22 aDULteratION
The application of carbon stable isotope ratio analysis has been very useful in detecting the
additionofcornandcanesugarstoapplejuice(DonerandPhillips1981).Whensweetenersareused
toadulterate,organicacidswillalsohavetobeaddedtoobtainthespeciiedsugar-to-acidratio.
ThedevelopmentofenzymicmethodsfortheanalysisofL-malicacidhasbeenabreakthrough
fordetectingtheadditionofsyntheticmalicacid(Evans,VanSoestbergen,andRistow1983).
Sharkasi, Bendel, and Swanson (1982) measured deviations in the sorbitol-to-sucrose and
sorbitol-to-totalsugarratiosfortheadulterationofapplejuice.
Sugar, nonvolatile acid, minerals, and UV spectral proiles were determined by Pilando and
Wrolstad(1992)forsevencommercialfruitjuiceconcentrates(hardpear,softpear,whitegrape,
pineapple,prune,ig,andraisin)andthreesweeteners(invertedbeet,invertedcane,andHFCS).
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