《魚糜及其制品加工》課件

第四章魚糜

及其制品加工

（SurimiandSurimiProducts）魚糜制品是我國(guó)的傳統(tǒng)產(chǎn)品，在中國(guó)烹煮飪史上相傳已久。福州魚丸，云夢(mèng)魚面，山東魚肉餃子等傳統(tǒng)特產(chǎn)是我國(guó)魚糜制品的代表，后來(lái)傳到日本，魚糜加工技術(shù)得到迅速發(fā)展1編輯課件ppt第四章魚糜

及其制品加工

（SurimiandS

生產(chǎn)魚糜的國(guó)家和地區(qū)主要有日本、韓國(guó)、泰國(guó)等。魚糜制品是日本的傳統(tǒng)食品，生產(chǎn)量很大。魚糜品種有蒸魚糕、烤魚糕、炸魚糕、烤魚卷、魚肉火腿、灌腸、魚肉蟹足等，它的原料大多是魚糜。目前，魚糜的主要商品形式是冷凍魚糜。浙江、福建等沿海地區(qū)也生產(chǎn)冷凍魚糜，但由于海洋漁業(yè)資源發(fā)生重大變化，主要經(jīng)濟(jì)魚種呈衰減趨勢(shì)，高檔魚糜制品所需的白肉魚（如鱈魚）嚴(yán)重短缺。我國(guó)淡水養(yǎng)殖業(yè)的發(fā)達(dá)，除鮮銷上市或速凍貯藏外，部分魚加工成冷凍魚糜。2編輯課件ppt生產(chǎn)魚糜的國(guó)家和地區(qū)主要有日本、韓

湖北省，每年淡水魚產(chǎn)量約為85萬(wàn)t，其中特別高產(chǎn)的白鰱已生產(chǎn)冷凍魚糜，作為魚糜制品的原料。魚糜：將魚肉經(jīng)采肉、漂洗、脫水和加入抗凍劑等工序而制成的肌原纖維蛋白，是半成品。Surimiisstabilizedmyofibrillarproteinsobtainedfrommechanicallydebonedfishfleshthatiswashedwithwaterandblendedwithcryoprotectants.Surimiisanintermediateproduct

3編輯課件ppt湖北省，每年淡水魚產(chǎn)量約為85萬(wàn)t，其中Before1960,surimiwasmanufacturedandusedwithinafewdaysasarefrigeratedrawmaterialbecausefreezingcommonlydeterioratedmuscleproteinsinducedproteindenaturation,whichresultedinpoorfunctionality.However,withthediscoveryofcryoprotectants,thesurimiindustrywasdeveloped.4編輯課件pptBefore1960,surimiwasmanufa第一節(jié)魚糜加工工藝原料魚處理→清洗→采肉→漂洗→脫水→精濾→加入抗凍劑→凍結(jié)

5編輯課件ppt第一節(jié)魚糜加工工藝原料魚處理→清洗→采肉一、原料處理

原料魚處理基本上采用人工方法。Heading,Gutting,andDeboning

先將原料魚洗滌，除去表面附著的粘液和細(xì)菌，可使細(xì)菌減少80-90%。然后去鱗或皮，去頭，去內(nèi)臟。剖割方法有兩種：1.背割沿背部中部往下剖2.切腹從腹部中線剖開(kāi)。再用水清洗凈腔內(nèi)殘余內(nèi)臟、血污和黑膜，這一工序必須將原料魚清洗干凈，否則內(nèi)臟或血液中存在的蛋白酶會(huì)對(duì)魚肉蛋白質(zhì)進(jìn)行部分分解，影響魚糜制品的質(zhì)量。6編輯課件ppt一、原料處理6編輯課件ppt7編輯課件ppt7編輯課件ppt8編輯課件ppt8編輯課件ppt9編輯課件ppt9編輯課件ppt10編輯課件ppt10編輯課件ppt

清洗一般要重復(fù)2-3次，水溫控制在10℃以下，以防止蛋白質(zhì)變性。國(guó)外在海船上加工，魚體的處理已采用切頭機(jī)、除鱗機(jī)、洗滌機(jī)和剖片機(jī)等綜合機(jī)器進(jìn)行自動(dòng)化加工，國(guó)內(nèi)一些企業(yè)也已開(kāi)始陸續(xù)配備這些設(shè)備，大大提高了生產(chǎn)效率。11編輯課件ppt清洗一般要重復(fù)2-3次，水溫控制在10℃以下，二、采肉（Mincing）用采肉機(jī)采魚肉，將魚體皮、骨除掉，而把魚肉分離出來(lái)的過(guò)程。國(guó)內(nèi)使用較多的是滾筒式采肉機(jī)。采肉時(shí)，魚肉穿過(guò)采肉機(jī)滾筒的網(wǎng)孔眼進(jìn)入滾筒內(nèi)部，骨刺和魚皮在滾筒表面，從而使魚肉與骨刺和魚皮分離。采肉機(jī)滾筒上網(wǎng)眼孔選擇范圍在3-5mm。aroll-typemeatseparatorThefishmeatispressedthroughtheorificesintotheinteriorofthedrum,whileseparatingskin,bone,hardcartilage,andotherimpuritiesintotheexteriorofthedrum.12編輯課件ppt二、采肉（Mincing）12編輯課件ppt

魚糜通常是用第1次采下的魚肉來(lái)進(jìn)行加工。任何形式的采肉機(jī)均不能把魚肉采取干凈，即在皮骨等廢料中尚缺留少量魚肉，為了充分利用這些蛋白質(zhì)應(yīng)進(jìn)行第2次采肉，但第2次采得的魚肉質(zhì)量要比第1次差，色澤較深，有時(shí)還帶一些碎骨屑，一般不作冷凍魚糜，而是用作炸魚糜制品的原料。

13編輯課件ppt13編輯課件ppt在工業(yè)化連續(xù)生產(chǎn)過(guò)程中，一般是把兩臺(tái)采肉機(jī)組合起來(lái)使用，一上一下，上面一臺(tái)作第1次采肉，下面一臺(tái)作第2次采肉。這樣，上面一臺(tái)采肉后的廢料就可作為下面一臺(tái)的原料直接投入，可節(jié)省勞力并提高效率。14編輯課件ppt在工業(yè)化連續(xù)生產(chǎn)過(guò)程中，一般是把兩臺(tái)采肉機(jī)組合起來(lái)使用，一上三、漂洗（Washing）漂洗可以除去魚肉中水溶性蛋白質(zhì)、色素、氣味和脂肪，提高魚糜白度和凝膠強(qiáng)度。它是魚糜生產(chǎn)的重要工藝技術(shù)，對(duì)提高魚糜制品質(zhì)量及保藏性起到很大的作用。Washingisanessentialstepinremovingwater-solubleproteins,primarilysarcroplasmicproteins,whichisthoughttoimpedethegelpropertiesofsurimi,andreduceproductquality.15編輯課件ppt三、漂洗（Washing）15編輯課件pptSarcroplasmicproteinsexistinthefluidswithinandbetweenmusclefibers,andincludemanymetabolicenzymesthatdiminishthestabilityoffunctionalproteinsduringstorage.Myofibrillarproteins,theprimarycomponentsthatpossesstheabilitytoformathree-dimensionalgelnetwork,constituteapproximately70%ofthetotalproteinsinmincedfishmeat.Areductioninwater-solubleproteinsinturnconcentratesthemyofibrillarproteins,thusenhancingthefunctionalpropertyofsurimi.16編輯課件pptSarcroplasmicproteinsexisti漂洗方法有清水漂洗和稀堿鹽水漂洗，根據(jù)肌肉性質(zhì)選擇漂漂洗方法。一般白色肉類直接用清水漂洗紅色肉、中上層魚類鮐魚、遠(yuǎn)東擬沙丁魚等用稀堿鹽水漂洗，以有效防止蛋白質(zhì)冷凍變性，增強(qiáng)魚糜制品彈性。17編輯課件ppt漂洗方法有清水漂洗和稀堿鹽水漂洗，根據(jù)肌肉性質(zhì)選擇漂漂洗方法清水漂洗主要用于白色肉魚類，如狹鱈、海鰻、帶魚、鰱魚等，介于白色肉與紅色魚之間的魚類也可使用此法。按比例將水注入漂洗池與魚肉混合，魚:水=1:5-10，慢速攪拌，使水溶性蛋白等充分溶出后靜置，使魚肉充分沉淀，傾去表面漂洗液，再按上述比例加水漂洗重復(fù)幾次。清水漂洗法會(huì)使魚肉肌球蛋白充分吸水，造成脫水困難，通常最后一次漂洗采用0.15%食鹽水進(jìn)行，便于肌球蛋白脫水。18編輯課件ppt清水漂洗主要用于白色肉魚類，如狹鱈、海鰻、帶魚、鰱魚等，稀堿鹽水漂洗主要用于多脂紅身魚類，先用清水漂洗兩三次，再以魚肉:稀堿鹽水=1:4-6漂洗五次左右，稀堿鹽水由0.1%-0.15%食鹽水溶液和0.2%-0.5%碳酸氫鈉溶液混合而成。漂洗技術(shù)關(guān)鍵一般來(lái)講，漂洗用水量和次數(shù)與魚糜質(zhì)量成正比，用水量和次數(shù)視原料魚的新鮮度及產(chǎn)品質(zhì)量要求而定，鮮度好的原料漂洗用水量和次數(shù)可降低，甚至可不漂洗，生產(chǎn)質(zhì)量要求不高的魚糜制品，可降低漂洗用水量和次數(shù)。一般對(duì)鮮度極好的大型白色魚肉可不漂洗。漂洗用水一般為自來(lái)水，水溫要求控制在10℃以下，避免使用高硬度水及富含銅鐵等重金屬離子的地下水。

19編輯課件ppt稀堿鹽水漂洗主要用于多脂紅身魚類，先用清水漂洗兩三次，再Washingefficiencyisoftenaffectedbyvariousfactors.Inadditiontothewater/meatratioandageoffish,thereistheshapeofthewashingtank(roundvs.square),thespeedoftheagitator,theshapeoftheagitator(verticalvs.horizontal),andwatertemperature.Square-shapedtanksseemtoworkbetter20編輯課件pptWashingefficiencyisoftenaf四、精濾（Refining）

用濾精機(jī)將魚糜中的細(xì)碎魚皮、碎骨頭等雜質(zhì)除去。紅色肉魚類所用過(guò)濾網(wǎng)孔直徑為1.5mm，白色肉魚類網(wǎng)孔直徑為0.5-0.8mm。精濾分級(jí)過(guò)程中必須經(jīng)常向冰槽中加冰，使魚肉溫度保持在10℃以下，以防魚肉蛋白質(zhì)變性。Beforethefinaldewateringunderascrewpress,impurities(suchasskin,finebones,scales,andconnectivetissues)areremovedbytherefiner.Therefiningprocessisusedtoseparateconnectivetissuesfromwashedmince.21編輯課件ppt四、精濾（Refining）21編輯課件ppt五、脫水魚肉經(jīng)漂洗后含水量較多，必須進(jìn)行脫水。脫水方法有兩種：一種是用螺旋壓榨機(jī)（ScrewPress）除去水分，另一種是用離心機(jī)離心脫水，少量魚肉可放在布袋里絞干脫水。溫度越高，越容易脫水，脫水速度越快，但蛋白質(zhì)易變性，從實(shí)際生產(chǎn)工藝考慮，溫度在10℃左右較理想。pH值在5.0-6.0時(shí)魚肉脫水性最好，但在此pH范圍內(nèi)魚糜凝膠形成能力最差，不宜采用。根據(jù)經(jīng)驗(yàn)，白色肉魚類在pH6.9-7.3，多脂紅色肉魚類在pH6.7脫水效果較好。22編輯課件ppt五、脫水22編輯課件ppt▲螺旋壓榨---ScrewPress

Themoisturecontentofmeatincreasesfrom82to85%to90to92%afterrepeatedwashing.Itisessential,therefore,toremovetheexcesswaterpriortoblendingwithcryoprotectantsandfreezing.Thedesirablemoisturecontentofthemeat,priortoblending,rangesbetween80and82%.

Thelengthandspeedofthescrew,thevolumereductionratio,andtheperforationofthescreensdeterminetheeffectivenessofwaterremoval.

23編輯課件ppt▲螺旋壓榨---ScrewPress23編輯課件pptForexample,ascrewpresswithalargervolumereductionratioandlongerscrewcanachievethesamedewateringeffectathigherspeedomparedtothescrewpresswithasmallvolumereductionoperatedatslowerspeed.Screenswith0.5to1.5-mmperforationsarecommonlyusedinindustry.Inaddition,screenswithsmallerperforationsareusuallyplacedattheendsectiontopreserverecovery.Itisnotuncommontousea0.1to0.3%saltmixtureofNaClandCaCl2tofacilitatetheremovalofwaterfromthescrewpress.24編輯課件pptForexample,ascrewpresswitTheuseofsaltoftenresultsinincreasedgelvalues.Addedsaltpositivelycontributestotheunfoldingofproteinstructure,resultinginbettergelstrengthwhentestingisdonewithinafewdaysaftermanufacturing.However,thisaddedsaltenhancesproteindenaturationduringfrozenstorageand,consequently,shortensthefrozenshelflifeofsurimi.Therefore,mechanicaldewateringwithoutsaltisbesttomaintainthefrozenstabilityofsurimi.25編輯課件pptTheuseofsaltoften六、加抗凍劑和斬拌-Cryoprotectantsandchopping

Theadditionofcryoprotectantsisimportanttoensuremaximumfunctionalityoffrozensurimibecausefreezinginducesproteindenaturationandaggregation.

Sucroseandsorbitol,aloneormixedatapproximately9%w/wtodewateredfishmeat,serveastheprimarycryoprotectantsinthemanufactureofsurimi.However,6%sucroseistypicallyusedinsurimimanufacturedfromwarm-waterspeciesperhapsduetohigherthermalstability.

26編輯課件ppt六、加抗凍劑和斬拌-Cryoprotectantsand

Inaddition,amixture(1:1)ofsodiumtripolyphosphateandtetrasodiumpyrophosphateat0.2to0.3%iscommonlyusedasbothachelatingagent,whichmakesmetalionsinsurimiinactive,andasapHadjustingagent.

Cryoprotectantswereoriginallyincorporatedintothedewateredmeatusingakneader.Currently,silentcuttersareoftenusedbecausetheyuniformlydistributecryoprotectantsfasterandthetemperatureincreaseslessduringchopping.27編輯課件pptInaddition,amixture(1:1)

?Commercialpracticesformixingcryoprotectants(100kgperbatch)usingakneaderandasilentcutterare6minand2.5min,respectively.

Thetemperatureofthemixmustnotexceed10℃

becauseattemperaturesgreaterthan10℃

,proteinfunctionalitycouldbedamaged.28編輯課件ppt?Commercialpracticesformi?Since1991,withthecommercialsurimiprocessing,enzymeinhibitors,suchasbeefplasmaprotein,eggwhites,orpotatoextracts,havebeenusedinconjunctionwithcryoprotectants,gelenhancers,andcolorenhancers.?Enzymeinhibitorsarecommonlyformulatedwithsucrose,sorbitol,sodiumtripolyphosphate,tetrasodiumpyrophosphate,calciumcarriers(calciumlactate,calciumsulfate,calciumcitrate,orcalciumcaseinate),sodiumbicarbonate,mono-ordiglyceride.29編輯課件ppt?Since1991,withthecommerc?

Theformulationoftheseingredientsvaries,dependingonthecompany.Therefore,thereareslightdifferencesfromonecompanytoanother.Theadditionofenzymeinhibitorsorcalciumcompounds,however,beforefreezingsurimiisnotnecessary,especiallybecauseaddedcalciumcompoundscanactuallyenhanceproteindenaturationduringfrozenstorage.Instead,thesecalciumcompoundscanbeaddedwhenthesurimipasteispreparedtomakeslow-cookedgels.30編輯課件ppt?TheformulationoftheseingDuetotherecentoutbreaksofBSE(bovineserumencephalopathy,ormad-cowdisease)intheEU,Japan,Canada,andtheUnitedStates,theuseofbeefplasmaasanenzymeinhibitorhasbeenprohibited.31編輯課件pptDuetotherecentoutbreaksof七、包裝、凍結(jié)Packagingand

Freezing?

Incommercialapplications,surimiisformedinastandard10-kgblockinaplasticbag,whichisthenplaceonastainlesssteeltray.Thetraysarethenplacedinacontactplatefreezerandheldforapproximately2.5hroruntilthecoretemperaturereaches-25℃.Afterinspectingthefrozensurimiblockswithametaldetector,two10-kgfrozensurimiblocksarepackedintoacardboardbox.

Drumfreezingofsurimiofferstheprospectofrapidfreezing,whichenhancessurimiquality.32編輯課件ppt七、包裝、凍結(jié)PackagingandFreezing按規(guī)格要求進(jìn)行定量包裝，2、4、6、10kg包裝為聚乙烯塑袋，包裝后的厚度為4-6cm。為了防止氧化，包裝時(shí)應(yīng)盡量排除袋內(nèi)的空氣。鮮魚糜應(yīng)盡可能在最短的時(shí)間內(nèi)送去凍結(jié)，通常使用平板凍結(jié)機(jī)。由于平板結(jié)機(jī)具有凍結(jié)速度快的特點(diǎn)，能迅速通過(guò)-1～-5℃的最大冰晶生成帶，這樣能保持凍結(jié)產(chǎn)品的細(xì)小冰晶，保證冷凍魚糜的凍結(jié)質(zhì)量。冷凍魚糜的品溫越低，越有利于冷凍魚糜的長(zhǎng)期保藏，所以冷凍魚糜的冷藏溫度要在-25℃以下，并要求冷庫(kù)溫度穩(wěn)定、少波動(dòng)。33編輯課件ppt按規(guī)格要求進(jìn)行定量包裝，2、4、6、10kg33編輯課件pp八、MetalDetectionMetaldetectionisacriticalcontrolpointforthesurimiHACCPprogram.FDAhassupportedregulatoryactionagainstproductswithmetalfragmentsof7to25mminlength.Processorsmustmakesurethattheunsafeproductdoesnotreachtheconsumer.Themostcommontypesofmetalliccontaminationinclude

ferrous,copper,aluminum,lead,andvarioustypesofstainlesssteel.Ofthese,ferrousmetalsaretheeasiesttodetect.34編輯課件ppt八、MetalDetection34編輯課件pptInsurimimanufacturingequipment,stainlesssteelalloysaremostcommonlyusedandarethemostdifficulttodetect.

Otherfactorsalsoaffectthesensitivityofmetaldetection,includingtheshapeofthemetal,orientationofthemetal,conditionoftheproduct(frozenvs.chilled),operationfrequency.35編輯課件pptInsurimimanufacturingequipm九、BIOLOGICAL(INTRINSIC)FACTORSAFFECTINGSURIMIQUALITY

EffectsofSpeciesThereareanumberofspeciesthatareutilizedasrawmaterialforcommercialsurimiprocessing.Dependingonthespeciesused,however,thefunctionalandcompositionalpropertiesofthesurimivary.Thefunctionalpropertiesofsurimidependoncomposition,butcannotgenerallybepredictedfromcompositionalanalysis.Itis,therefore,importantforprocessorstounderstandtherelationshipsbetweenthephysico-chemicalfunctionsoffishandthefunctionalandcompositionalpropertiesofsurimi.36編輯課件ppt九、BIOLOGICAL(INTRINSIC)FACTOWiththedevelopmentofsurimi,theimportanceofunderstandingtheintrinsicenzymesinthefishhasbeenhighlighted.Anetal.identifiedtheenzymesinPacificwhitingascathepsinsB,H,andL.Theybehavedifferentlywithdifferentenvironmentalconditions,suchaspH,temperature,andionicstrength.CathepsinBandHareeasilywashedoffduringsurimiprocessing,whilecathepsinLremainsinthemuscletissue.37編輯課件pptWiththedevelopmentofsurimiCathepsinLhasanoptimumtemperatureof55°Candcausestexturaldeteriorationwhenthesurimipasteisslowlyheated.Therefore,enzymeinhibitorsarerequired

unlessthesurimiiscookedrapidlyusingeitheranohmicheaterormicrowave,oristhinlyextrudedandcookedrapidly,asincrabstickprocessing.38編輯課件pptCathepsinLhasanoptimumtemArrowtoothflounder（比目魚）isanotherfishthatrequiresenzymeinhibitorstominimizetexturaldeteriorationduetoaheat-stableenzyme.

Gelweakeningataround55to60°Chasalsobeenreportedinthreadfinbream（馬鲅）,Atlanticmenhaden（鯡魚）,whitecroaker（白姑魚）,ovalfilefish（豚魚）,andlizardfish.39編輯課件pptArrowtoothflounder（比目魚）isanAlaskapollockhasbeenknownasafishthatgivesnoproteolyticenzymes.However,recentstudiesindicatethatAlaskapollockisinfestedwithmicrosporia（小孢子蟲）,whichinducegelsoftening.Theinfestedmusclecontainsaproteasethatdegradesmyofibrillarproteinsataround50to60°C.

Cycteineproteaseinhibitorswereabletoreducetheenzymeactivity,

whereasspecificinhibitorsofserineproteasesandasparticproteaseswereineffective.40編輯課件pptAlaskapollockhasbeenknownTomakesurimifromoily/darkorred-fleshedfish（紅肉魚）,suchasmackerel（鯖）,sardine,andsalmon（大麻哈魚）,certainstepsmustbetakentonegatetheeffectsoftheoilandhemeproteins.Hemeproteins,suchasmyoglobinandhemoglobin,accountfortheredcolorofdarkmuscle.Inaddition,fatoxidationindarkmuscleispromotedbyhemeproteins,whichcausesanoffensive,rancidodortodevelop.41編輯課件pptTomakesurimifromoily/darkItisthereforesuggestedthat0.1to0.5%NaHCO3inthefirstwashingsolutionbeusedtoremovetheextraoil.Additionof0.05to0.1%sodiumpyrophosphateandtheuseofavacuumduringwashingarealsorecommendedtoremovehemeproteins.42編輯課件pptItisthereforesuggestedthat

EffectsofSeasonalityandSexualMaturityCompositionalpropertiesoffishvaryasthefishingseasonchanges.InAlaskapollock,proteincontentwashighest(19.0%)inNov.andlowest(16.5%)inMay,whilemoisturecontentwashighest(82.3%)inJulyandlowest(80.2%)inNov.Thehighestmoisturereading(84.5%)forPacificwhiting（大西洋鱒）wasrecordedinApril,whilethelowestreading(80to82%)attheendofOct.43編輯課件pptEffectsofSeasonalityandSProteincontentwasatitslowest(14to15%)inApril,andthenincreasedandheldrelativelysteady(15.5to16.5%)afterJune.Fatheldfairlysteady(0.5to1.5%)untilAugust,andthenstartedtoincrease(1.5to2.5%)inOct.Therefore,forPacificwhitingsurimi,bothyieldandqualityincreaseduringthesummermonths.44編輯課件pptProteincontentwasatitslowSeasonalchangesinthefatcontentofsardineharvestedinthemiddlePacificOcean.InAug.,thefatcontentwasashighas33%andwasthelowestinAprilat3%.Consequently,tomanufacturesurimifromsardinesinsummer,duetothehigherfatcontent,specialtechnologiesusingNaHCO3andacentrifugingdecantermustbeapplied.Ingeneral,fishharvestedduringthefeedingperiodproducethehighest-qualitysurimi.Duringthisperiod,fishmusclehasthelowestmoisturecontentandpH,aswellasthehighesttotalprotein.

45編輯課件pptSeasonalchangesinthefatcoTherefore,fishharvestedduringandafterthespawning(產(chǎn)卵)seasonproducethelowest-qualitysurimi.IthasbeenestablishedthatspawningfishhavearelativelyhigherpHandtendtoretainmorewater.Consequently,itisdifficulttoremovetheextrawaterfromthewashedmeat.Toeasilyremovetheextrawater,muscletissuecharacteristicsmustbealteredbyeitherloweringthepHorincreasingthesalinityofthefinalwashwater.However,thisalterationcanleadtosignificantlyreducedquality,particularlyafterfrozenstorage.46編輯課件pptTherefore,fishharvestedduri

EffectsofFreshnessorRigorThefreshnessoffishisprimarilytime/temperaturedependent.Duetoendogenousenzymes

activatedbyrisingtemperatures,Pacificwhitingisprocessedwithinashortertimeperiod:within20hrafterharvest.Thebiochemicalandbiophysicalchangesduringthedevelopmentofrigormortisinducesignificantchangesinthefunctionalpropertiesofmuscleproteins.47編輯課件pptEffectsofFreshnessorRigoFishshouldbeprocessedassoonaspossibleaftergoingthroughrigor.

Priortopassingthroughthisstage,about5hrinthecaseofpollocksurimi,itisdifficulttoremovethe“fishy”odor,variousmembranes,andothercontaminantsthataffectproductquality.However,Significantlyhigherproteincontentandyield,reducedcookingloss,andenhancedgel-formingabilityareassociatedwithsurimiprocessedfrommanuallyfilletedpre-rigortilapiafish（羅非魚）.Thelengthoftimethatfishcanbeheldiniceorrefrigerationbeforeprocessingvaries,dependingonthespecies.48編輯課件pptFishshouldbeprocessedassoTheeffectoftimeisespeciallyprominentinfish,suchasPacificwhiting,thathaveintrinsicenzymeproblems.Time/temperatureeffectsonthecompositionalandfunctionalqualityofPacificwhitingsurimiissignificant.Ifkeptrefrigerated,Pacificwhitingshouldbeprocessedwithinapproximately24hrofcapture.Otherwise,thequalitybeginstodecline.IfPacificwhitingarenotcooledquickly,processingmustoccurwithin8to10hr.49編輯課件pptTheeffectoftimeisespecialCurrentpracticeofsurimifromthreadfinbreamorotherwarm-waterspeciesinThailandutilizes40%frozenfishmixedwith60%freshfish.Manufacturingofsurimifromfrozencold-waterspeciesisvirtuallyimpossibleandresultsinnoorextremelypoorgels.Itispossible,however,tomakedecentsurimifrom

frozenwarm-waterspeciessimplybecauseofitshigherthermalstability.However,bettersurimicanbemanufacturedfromwarm-waterspeciesiffreshfishisused.50編輯課件pptCurrentpracticeofsurimifro十、PROCESSING(EXTRINSIC)FACTORSAFFECTINGSURIMIQUALITY

HarvestingSurimiqualityisaffectedbytheharvestingconditionsandmethodsusedforcapture,aswellastheon-boardhandlingmethodsandvesselstorageconditions.Thegeographiclocationofthefishinggroundsmayalsoaffectqualityanddeterminefactors,suchasthesizeofthefishortheamountoftimerequiredtodeliverthefishtotheprocessingplant.51編輯課件ppt十、PROCESSING(EXTRINSIC)FACTOSeveralfactorsintheactualcaptureoffishcanalsoaffectfinalproductquality.Theseincludeat-seaweatherconditions,capturemethods,saltuptake,andthetemperatureofthefishpost-capture.

Althoughfreezingofgadoidfish,suchaspollock,severelydecreasesproteinfunctionality,threadfinbreamappeartowithstandproteindenaturationduringfrozenstorageandproduceanacceptableproduct.52編輯課件pptSeveralfactorsintheactual

On-BoardHandlingTimeandtemperatureofthefishbetweencaptureandprocessingcanbeconsideredtwoofthemostimportantfactorsthataffectfinalsurimiquality.Factorytrawlershavetheadvantageofprocessingatseaandusuallyproduceafinalproductwithin12hrafterharvestingthefish.However,fewfactorytrawlershavesystemsthatallowthemtochillthefishwhilewaitingtobeprocessed.Holdingtemperaturesat4to6°Ccanmakeasignificantdifferenceinsurimiqualitycomparedtofishheldcloseto0°C.53編輯課件pptOn-BoardHandling53編輯課件ppt

WaterTheimportantqualityfactorsassociatedwithwateraretemperature,hardnessormineralcontent,pH,andsalinity.Thelevelofchlorinationinthewatershouldalsobeconsideredbecauseofitsbleachinganddeodorizingeffects.

54編輯課件pptWater54編輯課件pptThewatermustberefrigerated

toatemperaturebelowwhichthefishmuscleproteinscanretaintheirmaximumfunctionalproperties.Thetemperatureofthewatercanvary,basedonthethermostabilityofthefishproteins.Warm-waterfishcanthereforetoleratehigherwatertemperaturesthancold-waterfishwithoutreducingproteinfunctionality.55編輯課件pptThewatermustberefrigeratedCa-activatedmyofibrillarMg–ATPasewashighestatthehabitattemperature(25.5°C)ofcarp.However,consideringthechangesinairtemperatureduringprocessing,therecommendedwatertemperatureforobtainingmaximumqualityis5°Corless.56編輯課件pptCa-activatedmyofibrillarMgTheoretically,softwaterwithminimumlevelsofmineralssuchasCa2+,Mg2+,Fe2+,Mn2+isrecommendedforwashing.Hardwatercausesdeteriorationoftextureandcolorqualityduringfrozenstorage.Inaddition,Ca2+andMg2+areresponsibleforthetexturechange,particularlywhensurimiisfrozen,whileFe2+andMn2+areresponsibleforthecolorchange.57編輯課件pptTheoretically,softwaterwithFurthermore,thepHofthewatermustbemaintainedatapproximatelythatofpre-rigorfishmuscletissue(6.8to7.0)toobtainhigherwaterretentionofthegels.Wellwater,dependingongeographicallocations,oftenshowssignsofhighhardnessandtypicallycontainscations(Ca2+andMg2+).Forlarge-scaleoperations,alime-sodaprocesscanbeusedtosoftenhardwaterbyremovingCa2+andMg2+.58編輯課件pptFurthermore,thepHofthewatHardwateristreatedwithacombinationofslakelime,Ca(OH)2andsodaash,Na2CO3.CalciumprecipitatesasCaCO3

andmagnesiumprecipitatesasMg(OH)2.Theresidualcontentofsodium(Na+)intheprocessingwaterdoesnotdirectlyaffectthequalityofthesurimi.However,theintakeofsodiumfromsurimicouldnegativelyaffectthenutritionalprofileofthesubsequentsurimiseafood.59編輯課件pptHardwateristreatedwithacTherefore,unlessreverseosmosis(RO)isusedtoremovesodiumions,theuseofadifferentsofteningmethodthatemploysamagnettoremoveCa2+andMg2+wouldbeideal.Beforewashing,thesalinityoffishminceisapproximately0.7%.Moistureremovalgraduallyincreaseswhenthepercentsaltconcentrationofthewashwaterisincreased.60編輯課件pptTherefore,unlessreverseosmoItiscommon,therefore,touseamixtureofNaClandCaCl2at0.1to0.3%inthefinalwashwater.However,specialcaremustbegiven.Residualsaltinsurimi(0.2to0.4%)wouldminimizethelossofsolubleproteinsduringwashingandgiveslightlyimprovedgelstrength.However,thisresidualsaltcontentwillacceleratethedenaturationoffishproteinsduringfrozenstorage(beyond2mo),resultinginamuchshorterfrozenshelflife.61編輯課件pptItiscommon,therefore,tousProcessingwaterhasalsobeentreatedwitheitherozone（臭氧）(O3）orUVlighttodisinfectbacteriaandotherpollutants.Becausethesechemicalsaredissipatedeasilyduringprocessing,theyareusedasaprocessingaidwithoutlabeling.Ozoneisapprovedasasanitizerforcontactwithfoodandfoodequipmentbecauseitiseffectiveagainstmanymicrobesandleavesnoresidueafteritreactsanddecomposes.62編輯課件pptProcessingwaterhasalsobeenUnlikeanotherstrongoxidizer(i.e.,chlorine),ozonedoesnotreactwithorganicmaterialstoproduceundesirablecompoundsanddoesnotleaveanunpleasanttaste.Accordingtotheindustrialtrialswithozonewaterinsurimimanufacturing,itreducesbacterialcountsaswellasincreaseswhiteness.63編輯課件pptUnlikeanotherstrongoxidizerAfterexposing0.6ppmfor30to60min,reducedbacterialcounts(2to3logs)andextendedshelflife(by1.2to1.6times)wereobserved.Theeffectofozoneonsurimicolorcanbeexplainedbasedonitsbleachingeffect.

Theporphyrinstructureofthehemepigmentisdestroyedduringozonation.64編輯課件pptAfterexposing0.6ppmfor30

Time/TemperatureofProcessingIncommercialsurimioperations,fishareusuallydeliveredtoprocessingplantswithin6to12hrafterharvest.Duetothelimitedcapacityofprocessingfacilities,thefishareoftenkeptinholdingtankswithicewater(~0°C)foruptoanother6to14hr.Thus,fishareusually6to24hrpost-harvestbeforetheyaresubjectedtosurimiprocessing.

65編輯課件pptTime/TemperatureofProcessiDuringthisholdingperiod,ifthefisharenothandledproperly,thetemperaturecanrise.Prolongedholdingtimeandelevated

temperaturescancausesevereproteolysisofmyofibrillarproteins.Consequently,proteolysisbeforeandduringprocessingcausesmoremyofibrillarproteinstobedissolvedaswater-solublewaste.66編輯課件pptDuringthisholdingperiod,ifTheeffectsofvariouspost-harveststoragetemperaturesandtimesontheproteolysisoffishanditsrelationshiptochangesinproteinsolubilitywereevaluated.

DegradationofMHC(myosinheavychain)increasedrapidlyduringthepost-harveststorageperiod.Thisdegradationoccurredevenwhenthetemperaturewasmaintainedat0°C.Incommercialoperations,fishiscommonlykeptinholdingtanks(~0°C)upto14hrbeforefisharesubjectedtoprocessing.

67編輯課件pptTheeffectsofvariouspost-haMHCorheavymeromyosinsubfragment-1(HMM-S1)68編輯課件pptMHCorheavymeromyosinsubfraResultsshowedthat23.5%ofMHCdegradationoccurredforthisstoragetime(0°C,14hr).GreaterdegradationofMHCwasobservedwithprolongedstorage.Morethan70%oftheMHCwasdegradedwhenfishwerestoredat0°Cfor72hr.MHCdegradationwasalsoaffectedbystoragetemperatures.Fishkeptat5°Cshowedhigherdegradationthanthosestoredat0°C,suggestingthaticewaterwasmoreefficientthanrefrigerationincontrollingproteolysis.69編輯課件pptResultsshowedthat23.5%ofMWhentemperaturesincreasedfurther,degradationoccurredmorerapidly.Withina14-hrstorageperiod,degradationnearlydoubledwhentemperaturesincreasedfrom0to10°C.Afterholdingat20°Cfor2hr,31.6%MHCwasdegraded,whichwasequivalenttothedegradationthatoccurredwhenfishwerestoredat0°Cfor24hr.Thesedata,therefore,indicatedthatbothtimeandtemperaturewerecriticaltoMHCdegradation.70編輯課件pptWhentemperaturesincreasedfuLowtemperaturesalsoslowedproteolysis.Withprolongedstoragetime,however,severedegradationoccurredalthoughthestoragetemperaturewasmaintainedat