食品速冻技术与冷链发展状况.pptx

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1、食品速冻技术与冷链发展状况年人均消费水平冷冻产品状况易腐食品低温运输状况易腐食品低温贮藏状况易腐食品低温贮藏状况（上海）冻结速度对食品质量的影响冻结与解冻过程特点特点 冻结 解冻热导率 W(m K)-12.2 0.5比热容 kJ(kg K)-12.1 4.2 食品与介质的温差 可充分低不可充分高溶质对冻结与蒸发温度的影响稀溶液中水的蒸气压比纯水蒸气压低在压力相同条件下，稀溶液中水的沸点高于纯水的沸点。在压力相同条件下，稀溶液中水的冰点低于纯水的冰点。研究热点问题速冻食品的质量问题 超高压速冻技术 快速冷冻技术 部分玻璃化技术 介电解冻技术实现上述技术的装备冷链建设与工艺管理问题螺旋速冻机螺旋速

2、冻机单体流化速冻机单体流化速冻机低温介质速冻机低温介质速冻机低温介质速冻机隧道式速冻机氢与电负性很强，且具有独立电子对、原子半径又较小的原子可形成氢键（如氮、氟）部分玻璃化技术部分玻璃化技术冷冻稳定剂较高的Tg冷冻保护剂较强保水性常用添加剂对粘度影响玻璃态热力学特征果蔬田间热与呼吸热TherespirationrateandtheproductionofCO2dependsmainlyonthestoragetemperature风冷风冷负压风冷水冷水冷水冷冰冷蒸发冷却Straw packinghouse真空冷却真空冷却装货移动式真空冷却设备Forced-Air Hydro Ice Vacuu

3、mTypical cooling time(hr)1-10 0.1-1 0.1-0.3 0.3-2 20-100Water loss(%)0.1-2 0-0.5 No data 2-4 0.1-2Water contact no yes yes,unless baggedno noPotential for decay contaminationlow high low none lowCapital cost low low high medium lowEnergy cost low medium medium high lowWater-resistant packaging neede

4、dno yes yes no noPortable sometimes rarely done common common noFeasibility of in-line cooling rarely done yes rarely done common noRoomComparison of Produce Effects and Costs for Common Cooling Methods风冷运输风冷运输低温运输国外应用示例Productarrivesfromthefieldonlinetrucks.Someisthencooledbyicingandsomeisvacucoole

5、d.Vacuumcoolinginvolvesplacingcartonsofproduceinachamberwheretheatmosphericpressureislowered.国外应用示例Thiscausestheboilingpointofwatertodropanditisboiledoff.Coldwaterissimultaneouslyaddedtothecartonssotheproductemergescoldandundamaged.Regularicinginvolvespackingeachcartonofproducewithice.At25poundsperc

6、arton,weusetons!国外应用示例BonipakProduceCompanycanmanufacture300tonsoficeeachdayandwecanstore400tons.Whenlargequantitiesofproductcomeintothecooleroverashortperiod,wecooltheproduceinourAirTunnels.Wehave8tunnels,whichhold14palletsofproduceeach.Thecartonsarecoveredwithatarpandcoldairisthenforcedthroughtheholesinthecartons.国外应用示例Overaperiodofhours,theproduceisslowlycooledtothedesiredtemperature.Thermometersconstantlymonitortheprocesssotheproductisnotovercooled.By e-By e