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1、單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,第二級,第三級,第四級,第五級,*,*,食品專業(yè)英語15 Low Temperature Storage 內(nèi)容不好電子課件,Low Temperature Storage,食品專業(yè)英語,Unit 15,Quick-Freezing of Foods,一,.,詞匯講解,二,.,課文閱讀,三,.,課后小結(jié),食品專業(yè)英語,Preservatio
2、n n.,保存，儲藏,Withdrawal n.,回收，撤回,Immersion n.,浸入，浸水,Convection n.,傳送，運(yùn)流，對流,Multiplate freezer,多層接觸式凍結(jié)裝置,Cryogenic adj.,制冷的，冷凍的，低溫實(shí)驗(yàn)法的,Fluidized adj.,流態(tài)化的，沸騰的,fluidized bed,流化床,Coating n.,薄層，涂層,Rancidity n.,脂肪酸敗，腐臭,Poultry n.,家禽,食品專業(yè)英語,shelf life 貨架期,refrigeration 制冷、冷藏,perishable 易腐敗的,multiply 乘、繁殖；多樣
3、的,tenderize 使嫩化、使軟化,coagulate 凝結(jié),Blanch v.,熱燙,blanching n.,漂白，熱湯,Freezing is,one of the more common processes for the preservation of foods.,Though it has been,recognized as a preservation technique for several hundred years,the major developments in its utilization have occurred only in the last ce
4、ntury.,The preservation of foods,by freezing depends on two principles:,冷凍是食品保藏較常見的加工方法之一。幾百年來，盡管人們一直認(rèn)為冷凍是一種保藏技術(shù)，但僅在上個世紀(jì)其應(yīng)用就有了重大發(fā)展。食品保藏有以下兩個原則：食品冷凍保藏基于以下兩個原理：,譯文,1,(a),all types of change that cause decay,whether due to living microorganisms or to the enzymes naturally present,are slowed down at low
5、 temperatures;and,(b),by freezing the water present in fresh foods it becomes,in effect,withdrawn from the food which can almost be considered,therefore,to have been dried.,(a),不論是活的微生物還是天然存在的酶類的原因，所有能引起食品腐敗的變化類型在低溫都會變緩慢；,(b),事實(shí)上，將新鮮食品中的水冷凍就相當(dāng)于將食品中的水移出，因此人們可以認(rèn)為食品得到了干燥。,譯文,2,Exposure of microorganism
6、s to low temperatures reduces their rates of growth and reproduction.This principle is widely used in refrigeration and freezing.The microbes are not killed.,低溫可以降低微生物的生長和繁殖速度，這一原理被應(yīng)用于冷藏和冷凍。此時，微生物并沒有被殺死。,譯文,3,Five types of freezing processes are used in modern food technology:,(a)Immersion Freezing,
7、The foods to be frozen are,plunged,directly into,a very cold solution.At one time,brine,was employed,particularly for freezing whole fish.Alternative freezing liquids that have more recently come into use are,invert sugar,solutions,particularly for fruit and vegetables.,現(xiàn)代食品工藝包括以下,5,種冷凍技術(shù)：,(a),浸入式冷凍
8、,將要冷凍的食品,直接浸入,到非常冷的溶液中。曾經(jīng)采用,濃鹽水,作為冷凍溶液，特別是用于冷凍全魚。最近選擇的冷凍溶液是,轉(zhuǎn)化糖,溶液，特別是用于果蔬冷凍。,譯文,4,A variation of immersion freezing is,the indirect contact system,in which the food is placed in a metal container and the container then immersed in a bath of refrigerated brine or some other freezing solution.,浸入式冷凍的
9、一種變化形式是,間接接觸體系,，在這個體系中，食品被放在一個金屬容器中，然后把容器浸沒在冷凍鹽水中或一些其它冷凍液中。,譯文,5,(b)Convection Freezing,(c)Multiplate Freezer,(b),對流式冷凍,(c),多層接觸式凍結(jié)裝置,譯文,6,(d)Cryogenic Freezing,This method which is being rapidly developed involves the exposure of food to a cooling medium at a very low temperature.,Liquid nitrogen,a
10、t a temperature of-195.8 has been used successfully on a commercial scale.The principle may be used in a number of ways.,(d),低溫冷凍,這種方法正處于快速發(fā)展之中，它是將食品與溫度極低的冷媒直接接觸來實(shí)現(xiàn)凍結(jié)的。,-195.8,的低溫,液氮,在工業(yè)規(guī)模化上已成功應(yīng)用。這個原理可以應(yīng)用于許多方面。,譯文,7,For example,strawberries immersed in liquid nitrogen for 30 seconds can be cooled fr
11、om 72(23)to 10(-12).Alternatively,the food to be frozen can be exposed to a spray of liquid nitrogen or to a blast of the very cold nitrogen gas.The rapid freezing achieved by these processed can give products particularly good flavor.,例如，將草莓浸沒在液氮中,30s,，可將草莓的溫度從,23,降到,-12,。還可將要冷凍的食品暴露在液氮的霧氣中或在強(qiáng)冷氮?dú)饬髦?/p>
12、。采用這些方法進(jìn)行速凍可賦予產(chǎn)品特殊的良好風(fēng)味。,譯文,8,(e),Fluidized-bed Freezing,：,In this process,a blast of cold air is blown upwards through a bed of the food to be frozen in such a way that the portions of food bounce up and down in the air flow and the entire mass behaves almost as if it were a liquid.,(e),流化床冷凍,在這個凍結(jié)
13、過程中，冷風(fēng)向上吹過裝有待凍食品的流化床，使得食品懸浮在氣流中，上下運(yùn)動，整個食品顆粒具有類似流體的表現(xiàn)運(yùn)動特性。,譯文,9,1.Fruits and vegetables,(a)Blanching,：,Although bacterial activity is brought to a halt at the customary temperatures at which quick-frozen foods are held,many of the enzymes present in vegetables remain active.It is,therefore,necessary
14、to blanch these foods.,1.,水果和蔬菜,(a),熱燙,盡管在食品速凍的溫度條件下，細(xì)菌沒有活性，但是存在于蔬菜中的許多酶仍保持活性。因此，這些食品需要熱燙滅酶。,譯文,11,Scalding for a short time in boiling water,or brief exposure to,live steam,destroys most enzymes.For water-scalding,the vegetables are passed through a tank of boiling water.,在沸水中進(jìn)行短時熱燙或通過,流通蒸汽,熱燙可以殺滅大
15、多數(shù)酶類。通過使用沸水流過蔬菜進(jìn)行沸水熱燙處理。,譯文,12,The enzyme peroxidase survives heat treatment for longer than many others.It is usual,therefore,when the conditions for quick-freezing a new product are being established,to continue blanching until a negative chemical reaction for peroxidase is obtained.,熱處理更長時間后，過氧化物
16、酶比其他酶更容易存活。因此，當(dāng)速凍一個新產(chǎn)品的條件建立后，通常繼續(xù)熱燙直到過氧化物酶發(fā)生負(fù)反應(yīng)為止。,譯文,13,(b)Freezing:,For freezing,the food,which may be packed in cartons or wrapped in plastic film,is cooled to 23(-10)to-35(-30)in as short a time as possible.Once the food is frozen,it is not necessary to maintain it at these low temperatures.,(b),冷凍,盒裝食品或塑料薄膜包裹著的食品在冷凍時，在極短的時間內(nèi)被冷卻到,-23(-10),到,-35(-30),。食品一旦被冷凍，就不需要在這么低的溫度下維持。,譯文,14,-,(c),（,c,）,Storage:,Storage should be at about-20(-4).Even at this temperature,some changes occur.For example,a
食品專業(yè)英語15 Low Temperature Storage 內(nèi)容不好電子課件
