食品的通电加热1

食品工程学的研究动向

1.食品工程学2.食品产业技术

3.食品材料的通电加热4.大米的营养和食味改善FoodProcessing&HeatingOperation(1)RawmaterialProcessingProducts

HeatingOperationThawingSterilizationCondensationDryingCookingAffectingFactors:physical,chemical,biologicalResults:Quality,productivity,energyefficiencyFoodProcessing&HeatingOperation(2)(露木,1998)FoodProcessing&HeatingOperation(4)HeatingOperationHeatingfromoutsideHeatingfrominsideRadiofreq.wave(f=13.56,27.12MHz)Microwave(f=915,2450MHz)Electriccurrent(f≦20kHz)ConvectionConductionRadiation

(FIR,f=0.3-60THz)HeatingfromOutsideandInsideHeatingfromoutsideHeatingfrominsideAdvantages:(1)fast,(2)uniformtemp.distri.,(3)energysaving,(4)goodop.conditionHeatHeatEMradiationPrincipleIrmsPowerOhmicheating～SampleElectrodeElectrodeVo,rms+－①Cationandanion:electriccurrentcarrier②Heatgenerated:Q=Irms・Vo,rms=P(W)RFW&Microwaveheating①Molecule:polarization,swing,vibration②Heatgenerated:Q=5.56×10-11・f・E2・εr’・tanδ(W/m3)③Depthwherethepowerisreducedto1/2:D≒3.31×107/(f・εr’1/2・tanδ)

(m)MicrowaveguideShieldchamberSample＋－ComparisonofOhmicHeatingandMicrowaveHeatingMicrowaveheatingOhmicheatingEquipmentTemp.distributionTemp.controlEnergyefficiencyShapeofmaterialHeatgenerationcomplex,expensivehomogeneousinalargeobjectpossibleabout70％nolimitdependsondielectriclossconstantsimple,cheapinhomogeneouseasyabove90％parallelsurfacesdependsonelectricconductivityMicrowave(R.freq.wave)heating1945:developmenttest1965:becamepopularasbigpowermagnetronwasdevelopedintheUSAFarinfraredradiationheatingAncienttimes:usesofnaturalstone,earthenwareforcooking1965:electricalFIwasdeveloped1973:FIRheatingbecamepopularforenergysavingduringoilshock1985:increaseofapplicationsinfoodindustryOhmicheating1919:sterilizationofmilk(USA),electrodecorrosion1975:cookingofvegetablesandmeat(USA)1984:sterilizationofjamandmiso,processingofbreadcrumb,kamaboko(Japan)1989,continuoussterilizationofsolid-liquidmixtures(Britain)(Omori,1998;Noguchi,1995)HistoricalFactsCommercializedOhmicHeatingEquipment(1)

(F.E.Co.,Ltd.)CommercializedOhmicHeatingEquipment(2)

(F.E.Co.,Ltd.)RadialelectrodesTubemodulesAxialelectrodes(I.F.M.Co.,Ltd.)(F.E.Co.,Ltd.)Platemodules(I.F.M.Co.,Ltd.)CommercializedOhmicHeatingEquipment(3)

(F.E.Co.,Ltd.)CommercializedOhmicHeatingEquipment(4)

(H.T.Co.,Ltd.)(F.E.Co.,Ltd.)4.食品材料的通电加热

(1)HeatingRateofRicePaste(2)RheologicalCharacteristicsofCoagulatedEgg(3)ThawingofFrozenFood

HeatingRateofRicePasteHeatingRateofRicePasteFig.Temperaturedistributioninthesample

(V0=1784V,Mc=43%,Sc=0%)7.527.517.5SampleThermocouples35HeatingRateofRicePasteMathematicalmodel:Where,

Assumptionformodeling:(1)noheatloss(2)uniformtemperaturedistribution(3)equivalentcircuitofonlyresistanceHeatingRateofRicePasteFig.Temperatureriseatdifferentvoltages(Mc=50%,Sc=0%)Fig.Temperatureriseofdifferentsamples(Vo=134V)4.食品材料的通电加热(1)HeatingRateofRicePaste

(2)RheologicalCharacteristicsofCoagulatedEgg

(3)ThawingofFrozenFood

RheologicalCharacteristicsofCoagulatedEggRheologicalCharacteristicsofCoagulatedEggP：応力(Pa)t：時間(s)ε：ひずみ(-)Ei：弾性率(Pa)τi：緩和時間(s)ηi：粘性係数(Pa・s)Ee：平衡弾性率(Pa)

RheologicalCharacteristicsofCoagulatedEggRheologicalCharacteristicsofCoagulatedEggRheologicalCharacteristicsofCoagulatedEggRheologicalCharacteristicsofCoagulatedEgg4.食品材料的通电加热(1)HeatingRateofRicePaste(2)RheologicalCharacteristicsofCoagulatedEgg

(3)ThawingofFrozenFood

鱼肉加工食品（Kamaboko,Chikuwa)ProblemsTimeinefficiencyMicrobialcontaminationInhomogeneoustemp.distributionProhibitivecostCurrentthawingoperationsLowtemperatureairFlowingwaterMicrowaveRadiofrequencywaveThawingofFrozenFoodGoodqualityNewtechnologyHighspeedLowcostOhmicHeatingIrmsPower～SampleElectrodeElectrodeVo,rms+－Cationandanion:electriccurrentcarrierAdvantages:●simple&cheapequipment●highheatingrate●homogeneoustemp.distribution●easytemp.control●highenergyefficiency(>90％)Disadvantages:●parallelsurfaces●electricconductivity

ProblemOriginalshape&changeinshapeoffrozenfoodDisconnectionofelectrodesandfrozenfoodSolutionElectrodeElectrodesolutionFrozenfoodNaClOhmicThawingofFrozenFoodOhmicThawingofFrozenFoodOhmicthawingrateelectricalmechanismofohmicthawing

FoodqualityOhmicThawingSystem21OhmicThawingofFrozenSurimiChangeofSurimitemperature

Ohmicheating:20V,2.0%Conventionalthawing:0oCchamberChangeofThawingRate

Theappliedvoltage:20VChangeofTemperatureDistribution

Theappliedvoltage:20V

AnEquivalentElectricCiruit

andChangeofTotalElectricPower(1)

Ohmicheating:20V,2.0%Ohmicheating:20V,2.0%ChangeofTotalElectricPower(2)