食品物性学多维标准尺度外文

MULTIDIMENSIONALREPRESENTATIONOFTHESTANDARDSCALESOFFOODTEXTUREM.A.CHAUVIN,C.PARKS,C.ROSSandB.G.SWANSONDepartmentofFoodScienceandHumanNutritionWashingtonStateUniversityPullman,WA99164-6376AcceptedforPublicationApril3,2008ABSTRACTTheuseofstandardterminology,standardreferencefoodsandstandardevaluationproceduresinthestandardscalesfortextureprofilemethodsmakesthemeffectiveobjectivetoolsforassessingpanelistsindescriptiveanalysis.However,theiruseisoftenlimitedbecauseofalackofavailabilityofstandardreferencefoodsandthedriftofscalesovertime.Theobjectiveofthisstudywastoevaluatethestandardtexturescalesfortheclassificationofthetexturalcharacteristicsofstandardreferencefoodsthroughtheuseofmultidimensionalscaling(MDS).Thetextureperceptionsoffoodsby11panelistswereevaluatedusingthestandardtexturescales.Eachscalewasanchoredbyaseriesofstandardreferencefoodsthatwerepurportedtoillustratetheintensitiesofthetextureattributeunderstudy.MDSwashighlyinstructiveinquantitativelyassessingthetexturaldifferencesperceptionsofnaivepanelists(r0.89).TheselectedfoodswereratedsimilarlyusingMDSandstandardtexturescales.PRACTICALAPPLICATIONSMultidimensionalscaling(MDS)isanefficienttoolfortheanalysisofsensoryperceptiondata.UsingMDS,itispossibletocorroboratestandardfoodtexturescalespublishedmanyyearsagoandassayfoodtexturemoreaccurately.Cautionisnecessarywhenassumingthatstandardscalesdevelopedinthepastareasusefultodayaswhentheyweredeveloped.Theitemdrifttheoryhypothesizesthatquestionsbecomelessreflectiveofaconceptovertimefornaturalreasons.ThepurposeofthisstudywastouseMDStoreproducetheoriginaldimensionsandoriginalorderofstandardstimuliusedtoanalyzeexistingfoodtexturalscalesforhardness,chewiness,gumminess,viscosity,adhesivenessandfracturability.INTRODUCTIONSzczesniaketal.(1963)developedaseriesofstandardfoodtexturescalesforthemechanicalpropertiesoftextureusingcommonfoodstorepresentselectedtextureswithintheentirerangeofcharacteristictextureintensitiesencounteredinfoods(Table1).UsingthestandardtexturescalesdevelopedbyBrandtetal.(1963),Szczesniaketal.(1963)developedthedescriptiveanalysistechniqueforfoodtexturedesignatedastheGeneralFoodsTextureProfile.TheGeneralFoodsTextureProfiletechniqueusesterminologytodescribebasiccategoriesorclassificationsoffoodtexturecharacteristicsdevelopedbySzczesniak(1963),fortrainingtextureprofilepanelists.Theprimarycharacteristicsofthefoodtextureprofiletechniquearestandardization,reproducibilityandcorrelationoftextureattributeswithinstrumentaldeterminationsoffoodtexture(CivilleandLiska1975).TheGeneralFoodsTextureProfilerepresentsexperimentaldesignofanorganizedandstructuredstudyoffoodtexture,specificallyto“studythesensoryanalysisofthetexturecomplexofafoodintermsofitsmechanical,geometrical,fatandmoisturecharacteristics,thedegreeofeachpresent,andtheorderinwhichtheyappearfromfirstbitethroughcompletemastication”(GeneralFoodsCorp.1967).Evaluationofthemechanicalcharacteristicsoffoodtextureisbothqualitativeandquantitativeandmaybeassessedbythestandardtexturescales.Standardtexturescalesusecategoryscalingtodesignatedifferencesintexturalattributes.Intextureanalysis,thecategoryscaleisusedtorepresenttheintensityoftheattribute,withthenumberofcategoriesvaryingwiththetextureattributescaled.Foreachtextureattributescale,thefullrangeofthetexturalattributeisdemonstratedusingstandardreferencefoodsthatpossesthetextureattributeasamajorproperty.ThestandardtexturescalesdevelopedbySzczesniaketal.(1963)arepracticaltoolstodemonstratetheprincipalrangeoftextureforeachspecifictextureattribute.SzczesniakscalesareevolvingandweremodifiedthroughouttheyearsbyanumberofresearchersincludingGeneralFoodsCorp.(1967),CivilleandLiska(1975),Szczesniak(1975)andMunoz(1986).However,theinitialpublicationbySzczesniak(1963)isconsideredahighlystandardizedreferencesystemforfoodtexture.Szczesniak(1963)concludedthattextureisadiscerniblesensorycharacteristicoffoodsandthatinsomefoods,suchasmeat,potatochips,cornflakesandcelery,texturemaybemoreimportantthanflavor.Theabilityofsensorypaneliststodistinguishandarticulatemechanicaltexturecharacteristicssuchashardness,viscosity,adhesiveness,fracturability,gumminessandchewinessoffoodsvariesamongindividuals.Thecomplexityofthehumanmasticatoryapparatus,culturaldiversity,healthstatus,age,sexandfoodpreferencesinfluencestextureperceptionoffoodsamongindividuals.Theuseofmultidimensionalscaling(MDS)canelucidatedifferencesamongpanelistsbyrevealinghowtheycognitivelygroupasetofstimuliaccordingtosomesetofattributes.TheMDSanalysisarrangesthestimuliinageometricspaceaccordingtostimulisimilaritiesasjudgedbythepanelists.Stimulithatarelocatedclosetogetherareconsideredsimilarwhilestimulithatarefarapartareconsidereddifferentbasedonthedimension(s)ofinterest.MDScanthusrevealhowthepanelistsorderthestimulionvariousattributessuchashardness,viscosity,adhesiveness,fracturability,gumminessandchewiness.MDSisamathematicaltechniquethatdescribesproximitiesamongobjectsonaspatialrepresentationormap(Schiffmanetal.1981).TheMDSmethodassumesthatsubjectiveestimatesofsimilarityordissimilarityrepresent