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1、MeasurementofFoodThermalConductivityUsingDifferentialScanningCalorimetryA.B.BUHRIandR.P.SINGHABSTRACTMATERIALS&METHODSTomeasurethermalconductivityoffoods,anattachmenttoadiffer-Apparatusentialscanningcalorimeterwasconstructed.AneedleprobewithaAnattachmenttotheDSC(
2、Perkin-ElmerDSC7)wasconstructed,40gaugetype-Tthermocouplewasusedtomeasurethetemperaturespecificallyformeasurementofthermalconductivity,asshowninofacylindricalfoodsample.TheDSCheatingpantemperaturewasFig.1.ConstructiondetailsareshowninFig.2,3,and4.Thealu-maintaine
3、dat4O”C,andthenraisedto50°C.Theaveragethermalminumheatsinkwaskeptataconstanttemperaturebypumpingglycolconductivitiesofrutabagas,radish,parsnip,turnip,potato,greenap-throughanembeddedcoppertube.Glycolwasalsopumpedthroughple,andcarrotwere0.447,0.499,0.392,0.480,0.5
4、52,0.405,andtomaintaintheturbulentchamberoftheDSCheadassemblyatthe0.564W/m”C,respectively,foratemperaturerangebetween40-50°C.sametemperatureastheheatsink.Theglycoltemperaturewasmain-TheDSCmethodwasreliable,precise,andarelativelyrapidtech-tainedbyatemperaturecontr
5、olbath.A40AWG,typeT,thermo-niquefordeterminingthermalconductivityoffoods.couplejunctionwaslocatedatthetipofa9mmlong,20AWGstainlesssteelneedle,andusedasaprobe.ThethermocoupleprobeKeyWords:thermalconductivity,fruits,vegetables,calorimetry,DSCwasinsertedintothefoods
6、amplethroughthethermocoupleguidehole.Thesampleholderwasconstructedusingaphenolicresin(k=0.04INTRODUCTIONW/m’(J).Thesampleholderwas6.5mminternaldiameterand12.7mmlongwithanaluminumbottom.DimensionsofthesampleholderINDESIGNINGandevaluatingheatingandcoolingprocessesi
7、ndicatetheuniqueadvantageofthismethod,namely,smallfoodthermalpropertydataareofvitalimportance.Infoodprocess-samplescanbeusedformeasurementofthermalconductivity.ing,anaccurate,reliable,andfastmeasurementtechniqueiscriticalforgatheringthermalpropertydata.Thethermal
8、con-ductivityoffoodscanbedeterminedusingeitheratransientExperimentalprocedureorasteadystatemethod.TransientmethodsinvolveuseofForaselectedfood,asamplewasobtain
