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Quality Changes of Frozen Meat During Storage and Control Measures

By Frank Harris,2014-01-11 16:06
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Quality Changes of Frozen Meat During Storage and Control Measures

    Quality Changes of Frozen Meat During

    Storage and Control Measures 中国肉类童壤合究中I

    CHlNAMEATRESEARCHCENTERWWW.Cmrc.com.cn

    肉类研究

    MEATRESEARCH

    2010.6

    F

    QualityChangesofFrozen

    MeatDuringStorageandControlMeasures

    DUJiangping

    (InstituteofFoodScienceandTechnology,YunnanAgriculturalUniversity,Kunming65020

    1,China)

    Abstract:Thefrozenisacommonmethodofmeat

    However,thequalityofmeatstillhavetakenplace

    storage,generallyapplicationsinmeatindustria1. changeseveninthelowtemperature,Thisarticle

    discussiononthechangesoffrozenmeatqualityduringfreezingstorage,andgivethecorrespo

    nding

    controlmeasures.

    Keywords:frozen;meat;quality;measures

    reezingisoneofthebasicmethodsofmeat

    preservation,andthemostwidelyused,mosteconomical andbestwaytomeatpreservation.Refrigerationcanlarge

    scalestorageandnotonlyrelativelylongstoragetime,butalso canadjustmeatmarketpricesandsupply.Frozenmeathavehigh securityfeaturescomparedtofleshmeat.Somestudieshave

    shown:porkmeatafterfrozenissaferthanfleshporkmeat. Frozenmeatisdefinedasfreshmeatfreezingpreservation belowminus18?.Butmeatalsoappearsomeunusual

    phenomenaatalongtermstorageoflowertemperature, resultsinreducedqualityofmeat.Thisarticlediscussion onthechangesoffrozenmeatqualityduringfreezing storage,andgivethecorrespondingcontrolmeasures. 1Thechangeofmeatqualityinfrozen

    storage

    1.1Thecolorchange

    Thecolorofmeatisthemostimportantinsenses, consumers,firstimpressionisthecolorofmeat.meat colorhavealargerchangerange,canbefromthedeep purpleoffreshmeattothelightbrownofbacon.Meat colorchangesarerelatedtothemyoglobin.Myoglobinisa water-solubleprotein,containingtheproteinpartandnon

    proteinporphyrinringswhichcentralhaveironatoms. Theoxidationstateofironatomshasamajorimpacton meatcolor,therefore,thecolorchangedependsofmeat primarilyonmusclemyoglobincontentanditsstate. Musclecolorchangefromthebrightcherryredtobrown wasacomprehensiveresultmainlyduetooxymyoglobin wasoxidizedintoMetmyoglobinandlipidoxidation. Eeceived:15January2O10

    Myoglobincombineswithoxygentooxymyoglobinin thepresenceofenoughoxygen,thecolorchangeintoa purplered.Ifcontinueoxidation,FeintoFe",generating Metmyoglobin,thecolorbecomeredbrown.Atlow

    temperatures,biologicalandbiochemicalchangeswas controlled,alsoinhibitmicrobialgrowthandreproduction,

    reducedthereactionrate,extendingtheshelflifeof muscle.Therefore,themeatwasatlowertemperature undertheconditionoffrozen,slowlydowntherate ofmusclecolorchange.Infrozenstorageistruethat temperaturesarelow,butvariousbiochemicalreactions andcold-resistantmicro?-organismssecretedwater--soluble orfatsolublepigmentcausingchangesofmeatcolorwith theextensionoftime.Forexample,fatoxidationbecomes paleyellowonthesurfaceofmeat.Ingeneral,meatcolor graduallydimming,withtheextensionofstorageperiod. Studyonthefrozentilapiaevery10daysforcolorsensory evaluation,thelongerfreezingperiodthecolorchangeis moreunsatisfactory.

    1.2ThechangeofOrganizatiOnalstructure

    (dry,corruption)

    Dryisannotignoredquestioninfrozenmeat.The shrinkageoffrozenfoodisdefinedaswaterevaporation fromthefoodsurface,causingmeatsurfaceroughness, pigmentconcentration,meatcolordeepened;frozenmeat surfaceappeardehydrationporouslayer,andbecome deeperwiththewatercontinuouslyevaporate.Thegapin meatwasfilledintoairandcanabsorbvarietyodorswhich intheair,andmakeastrongoxidationandhydrolysis reactionsofprotein,fat,allkindsofflavorcompounds. 207o耳第6期总第j;o

    l樊研梵|

    Leadtovariousharmfulsubstancesorstrangeodor substance,meatdeterioration,cannoteat.Duringfrozen storageprocess,icecrystalsformationbecomeslarger leaddehydrationdegenerationofmusclefiberprotein.

    Electronmicroscopyobservationshowedthatmusele fibershadvisiblecracks,voids,thethickandfilaments wirea~angedirregularlyandloose,thesarcomere,Aband andIband.crossstriationsstructurestructurebecome fuzzyorevendisappear,thez-linedistortion,fracture, severedissolveddisappear,myofibrilgeneratealarge numberofbubbles,andsoon.Ifgavepressureinfrozen storage,wil1be1eadtosarcomereandOrganizatiOna1 structurechangeinthetexturepropertiesoftheserious. K.S.Y0oninvestigatedtheeffectsOfl0%NaC1,trisodium phosphate(TSP),sodiumtripolyphosphate(STPP),and tetrapotassiumpyrophosphate(TKPP)treatmentson texturalandmicrostructura1propertiesofchickenbreasts duringl0monthsoffrozenstorageat.20?.Observedthe

    structureofmuscleshowthatlargeicecrystalsdistorted thestructureofmyofibrilsofbreastmeatwithsarcomere unitsshrunk.butMandZlineswerestillvisible.These observationssuggestthaticecrystalformationinmuscle didplayaroleinthequalitychangesinthefrozen chickenbreast,andonlyTSPandSTPPpreventedthe icecrystalformation,whichsuggeststhatstabilizing themyofibrillarproteinorganizationwithouticecrystal formationduringfrozenstorageisakeytomaintaining thequalityoffrozenchickenbreastafterextendedfrozen storage.F.FERNANDEZMARTINstudyontheprotein

    denaturationandstructuraldamageduringhigh?-pressure?- shiftfreezingofporcineandbovinemuscleconclusionthat porkandbeefmusclesweresubjectedto200?IPaand220.C

    withorwithoutwaterfreezing,proteindenaturationwasgreater

whenfreezingoccurred.Pressureinducedcolddenaturation

    wascompleteforactinandveryconsiderableformyosin andothermuscleproteins.Connectiveproteinsremained practicallyunalteredbypressurizationand/orfreezing. Structura1changesinthemuscleatsarcomere1evelscaused bypressurizationweremoreseverewhenfreezingoccu~ed. color,driploss,andtexturalpropertiesonthepressurized samplesalsorevealedanadditiona1deleteriousinfluence offreezing.Pressurizationa1oneandpressureshift

    freezingresultedunsuitableformusclepreservation. 1.3TheCompositionChange

    Frozenmeatoccurlipidauto.oxidationandalsobesubject todegradation,freefattyacidcontentincreaseswith prolongoffrozenstorageperiod.Throughdetermined theporkmeatwhichfrozen18?for15monthsfound

    thatthatmostmeatisstillfreshthepH,volatilebasic nitrogen,acidvalue,peroxidevalueindicatorstomeetthe requirements.demonstratethatporkrefrigeratedina18?

    environmentmorethanoneyear,therewasnosignificant changeinmeatquality,butfatoxidationrancidityserious. meatfrozenin18?upto13monthsshowthatchangesin

    totallipidsofrawmeatduringfrozenstoragewerelargely duetolossesinthetrigiyceridefraction.Thephospholipids contentoffrozenrawmeatwasrelativelyconstant, irrespectiveoflengthoftimeinfreezerstorage.Frozen 1ambmeatTVBNvalueincreasedwiththeextension ofstorageperiod,andstoragetemperaturemorehigher theincreaseOfTVBNvaluemorefaster.Inaddition, somewatersolublevitaminswillbelostwiththeiuice afterthaw.Thisismainlywiththemethodsofthawing;

    generallywatersolublevitaminswillbelossgraterwith waterthawing.Somevitaminswhicharesensitivewith lowtemperaturealsocanlossinfrozen.

    1.4Changesofmicro-organisms

    Thefrozentemperaturemorelower,growthmoreslowly ofmicroorganisms.Atthreedifferenttemperaturesfrozen muttonmeat,15?,20?,25?respectively,during

    frozenstorageprocess,thebacteriagrowslowlyatall temperature,atthesamepoints,bacteriaweresignificantly higherquantityat15?than-20Cand25?.Although

    thenumberofmicroorganismsincreasedinstoragetime, the12?frozenchickenmeatconsumptioninthree months,bacterialcountsdoesnotexceedlimitvalues quantity.Freezethawingcouldaffecttheproportionof grampositivebacteriaandgramnegativebacteria,as

    mayhavebeenexpectedasGrampositivebacteriaare

    lesssensitivetofreeze--thawinjurythanaregram--negative bacteria.StudieshaveindicatedthatClostridiumbotulinum sporesinoculatedintocookedchickenmeat,wouldbe reducedby53%inthefrozenstorage.another15%ofthe

    sporesreducedduringfrozendehydrationstorage.Sothe dehydratedproductsoflongtermstoragedonotworry

    aboutClostridiumbotulinumsporessurviving.Chicken meatafterfrozen.approximately21%oftheaerobesand 37%Oftheanaerobessurviveddryingandrehydrationat roomtemperature.Inaddition,themicroorganismstypes

    andcountsarerelatedtothespeciesandpHofmeat infrozenstorage.Infrozenmeat,somecoldresistant

    microorganismscanalsogrowthinitssuitablepH. 2Factorsaffectingthequalitychange

2.1Pack

    Meatpackagingplayanimportantroletoextensionthe frozenrhythmandprotecttheirquality.Studyshowedthat frozenthesameperiod.intactpackbeefonthevalueof TVBNlowerthannopackagingnearly3mg/1OOg,fully illustratedtheimportanceofpackagingprolongfrozen beefshelf.Vacuumpackagecanincreasethestabilityof sensesat.18?frozenstorage.

    2.2Thefreezingprocess

    Meatfreezingprocessisusuallydividedintodirect 2oo耳第6瑚总第?6期一互至

    _l际交流

    freezingprocessandtwophasefreezingprocess.Studieshave shownthattwophasefreezingprocesscanbetterimprovemeat qualitymorethandirectfreezingprocess.Porkmeatfreezing 40d,TVB-Nvalueincreaseandcontentisloweroftwophase freezingprocessthandirectfreezingprocess.Directfreezing processonlyashorttimeandlesswaterloss,cansavinglabor andelectricity,reducingfloorspaceandlowinvestment costs.Frozenmeatcolorchangeswererelatedtotherate offreezeandmeatcolorwasmorestableinasuitablelow temperatureanddarkenvironmentwhenfreeze.

    2.3FrozenTemperature

    Inacertainperiodandtemperature,temperatures morelowermeatqualitymorebetter.Theacidvalue graduallyincreasedwithfrozenprolongatdifferent frozentemperatures,butchangesmoreslowly.QIN Ruishenginvestigatingeffectofdifferentstorage temperature(15?,20?,25?)onqualityof

    frozenlamb,Theresultindicatedthat,acidvalue(AV)

    increasedwithstoragetime,acidvalue,respectively 2.52,2.27,2.13mgKOH/g.Comparedtocoldstorage, frozenstoragecarlkeepthequalityandprolongtheshelflife offrozenlamb.Comparedwithinitial,AVwasincreasednot clear,andthelowertemperaturethesmllerproportionwater loss.Themeatcolorgenerallychangefrombrightredto brown,itisdirectlyrelatedtotemperature.

    2.4Frozenperiod

    Meatqualitydeclinewiththeprolongofstoragetime.The surveyofsplitcamelmeatqualitychangesduringfrozen storagedemonstratethatundernormalfrozencondition, divisionofcamelmeatstorage12monthscankeepfresh; 14months,hasdroppedtosubfreshstandards;morethan 14monthsbegantodegenerate.Soconsiderfrozenshould baseonthecharacteristicsofdifferentmeatproductsand marketsupplyandfactoryequipmentandotherfactors. 2.5airhumidityandvelocity

    Theairhumidityisdirectlyrelatedtoshrinage,humidity lessthanthefrozenstandards,shrinageseriously.Below

    18?.microbialgrowtheffectlittlebytemperature. Considerforreductionmeatshrinkage,relativehumidity requirehigher,usuallybetween95%98%.Poorairflow

    willmaketheunevendistributionofmoisture,leadingto differencesbetweenmeatqualities.Frozenroomairflow generalcontrolbetween0.20.3m/s.

    3ControlMeasures

    3.1Fastfreeze

    Vacuumcoolingisanidealrefrigerationtechnology,it hasmanyadvantagescomprisetoothercoolingmethods,

    itisthefastestmethodofrefrigerationbyfarandcooling evenlyincoolingprocess,cleanandnopollution,can wellguaranteedthefoodquality.QuickFrozenMeat qualitybetterthanslowfreezing,icecrystalsformsmall

    anduniforminquickfrozen.canquicklydecreasethe

    meattemperaturebelowmicrobialgrowthrequired,and decreasethedenaturationofproteinbyreducecontext timeofconcentrationsolutewithmeatcomponentduring freeZingprocess.HavestudyfoundthatpHdecreaserapid postmortem,ifaccompaniedhighertemperature,can appearthePSE(pale,soft,andexudative)meat.Therefore, rapidcoolingcanpreventPSEmeatformationandprevent thechangeofmeatcolor.

    3.2avoidgreatlyvolatilityoftemperatureand humidityaboutcoldroom

    Thecoldroomtemperaturef1uctuationswillcause increasesofmeatshrinage,so,temperatureshouldbe maintainedattheminimumrequiredwhenmeatwas frozen.andmeattemperatureatlestbelow3?thancold

    tomtemperatureandthenstoragetoensurethestabilityof temperaturebetweenstorageperiod.Temperaturefluctuations willcausemeatrecrystallization.sothatsmal1icecrystalswil1 reduce,largeicecrystalsgraduallyincreasedandbigger, musclecellsleadtomechanicaldamageandaccelerate thelossofcellsapafterthawing.Somustfrequentlyto checkthetreasurysealandmaintainareasonabledatabase airflow.Thehumidityisalsoimportant,generallythe higherthebetter,generallymaintainedabout98%,itwill betopreventtheshrinageduringfrozen.

3.3Frozencombina廿onwithothermethods

    Combinationsfreezingwiththeotherfreshmeasures arebettertomaintainmeatqualitythansingleuseof freeze.Frozenadditioncrossingicecoattofrozencarp, afterstorage130dtheTVBNcontentsimilartouse

    onlyfreezingstorage70d.Studyshowwhendietary supplementationofthedietofpigswitha-tocopheryl acetateincreasesmusclea-tocopherolcOncentratiOnsand stabilizespolyunsaturatedfattyacidsandcholesterolin muscleagainstoxidativedeteriorationandalsoimproved theflesh,nutritionandqualityofmeat.

    3.4useappropriatethawingmethods

    A11thethawingmethodsbothhaveadvantagesand disadvantages,inthemeatprocessingindustry,itis necessarytoselectsuitablethawingmethodsfordifierent meat,whilealsoconsiderotherfactorssuchasproduction, equipment.Forexample,usemicrowavethawing,itis fastandhighefficiency,buteasilycausedoverheating effectinthemeltregionbecausethedifferencepenetration andabsorptionofwaterandice.Waterthawingcan avoidweightlossandfast,butthereismicrobiological contaminationfreezemeatandthesolublematerialwill beloss.Althoughthevacuumfreezequickly,waterlossis moreseriousandneedlargeinvestmentonequipment. 2070年第6期总第736

    TranslatefromMeatResearch2009.11,ppl417

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