一、幹製的基本原理
幹gan肉rou製zhi品pin又you稱cheng肉rou脫tuo水shui幹gan製zhi品pin,是shi肉rou經jing過guo預yu加jia工gong後hou利li用yong自zi然ran或huo人ren工gong的de方fang法fa脫tuo出chu肉rou中zhong一yi定ding量liang的de水shui分fen,將jiang其qi水shui分fen活huo度du降jiang低di到dao微wei生sheng物wu難nan以yi利li用yong的de程cheng度du而er製zhi成cheng的de一yi類lei熟shu肉rou製zhi品pin。肉rou類lei等deng易yi腐fu食shi品pin的de脫tuo水shui幹gan製zhi,既ji是shi一yi種zhong貯zhu藏zang手shou段duan,也ye是shi一yi種zhong加jia工gong方fang法fa,對dui於yu不bu同tong類lei別bie的de幹gan肉rou製zhi品pin來lai說shuo,脫tuo水shui幹gan製zhi可ke能neng是shi其qi主zhu要yao的de加jia工gong過guo程cheng,也ye可ke能neng隻zhi是shi整zheng個ge加jia工gong工gong藝yi過guo程cheng中zhong的de一yi個ge環huan節jie。肉rou品pin中zhong含han水shui量liang一yi般ban高gao達da70%,經脫水幹製後,不僅極大地縮小了產品的體積,而且可以使肉品中水分含量降低到6%~20%。由you此ci可ke見jian,肉rou品pin幹gan製zhi的de基ji本ben原yuan理li就jiu是shi通tong過guo脫tuo去qu肉rou品pin中zhong的de一yi部bu分fen水shui,使shi肉rou中zhong微wei生sheng物wu的de活huo動dong和he酶mei的de活huo力li得de到dao抑yi製zhi,從cong而er達da到dao加jia工gong出chu新xin穎ying產chan品pin或huo延yan長chang貯zhu藏zang時shi間jian的de目mu的de。
水分是各種微生物生長發育過程中所必需的一類營養物質,但並非所有的水分都能被微生物所利用,如添加一定數量的糖、鹽的水溶液,其大部分水分就不能被微生物利用。因此,把能被微生物、酶化學反應所利用的水分稱為有效水分,並采用水分活度(Aw)laihengliangyouxiaoshuifendeduoshao。meiyizhongweishengwushengchang,douyousuoxudezuidishuifenhuoduzhi,dangroupinzhongshuifenhuoduzhidiyuzuidizhishi,weishengwufanzhishoudaoyizhi,dangroupinzhongshuifenhuoduzhigaoyuzuidizhishi,weishengwuzejiyifanzhi。tongchangxianrou、煮製後鮮製品的水分活度在0.99左右,而黴菌、酵母菌需要的水分活度分別在0.80、0.88之上,細菌生長所需的水分活度在0.91~0.99zhijian。youcikejian,jinjinjiangrouleijinxingzhuzhibingbunengdadaochangshijianzhuzangdemude,zhiyoujiangzhuzhihouderoupinzaijinxingganzhi,jiangdishuifenhuoducainengyizhirouzhipinzhongdaduoshuweishengwudeshengchang,jinerdadaoyanchangzhuzangshijiandemude。danshibixuzhichu,yibanganzaotiaojianxia,bingbunengshirouzhipinzhongdeweishengwuwanquanzhisi,zhishiyizhiqihuodong,ruoyihouhuanjingshiyi,weishengwurenghuijixushengchangfanzhi。yinci,rouleizaiganzhishiyifangmianyaojinxingshidangdechuli,jianshaozhipinzhongdegeleiweishengwushuliang;另一方麵幹製後要采用合適的包裝材料和包裝方法,防潮、防汙染。
幹肉製品的保藏性除與微生物有關外,還與酶的活力、脂肪的氧化等因素有關。隨著水分活度的降低,幹肉製品的穩定性增加,但脂肪的氧化與其他因素不同,在水分活度為0.2~0.4時反應速度最慢,接近無水狀態時反應速度又增加。實驗證明脫脂幹肉製品的含水量為15%時,其水分活度值低於0.7,因此,幹肉製品的含水量低於20%時較為適宜。
二、影響肉製品幹製的因素
肉製品在幹製中最基本的現象是脫水作用。肉製品的脫水是兩個擴散作用交替進行的結果;當肉製品原料暴露在幹燥介質(加熱空氣)中時,由於與熱空氣接觸,肉製品表麵的水分受熱變成水蒸氣而大量蒸發,稱為水分外擴散;當dang表biao麵mian水shui分fen低di於yu內nei部bu水shui分fen時shi,造zao成cheng肉rou製zhi品pin內nei部bu與yu表biao麵mian水shui分fen之zhi間jian的de水shui蒸zheng氣qi分fen壓ya差cha,此ci時shi水shui分fen就jiu會hui由you內nei部bu向xiang表biao麵mian轉zhuan移yi,稱cheng為wei水shui分fen內nei擴kuo散san。一yi般ban來lai說shuo,在zai幹gan製zhi過guo程cheng中zhong水shui分fen的de內nei、外擴散是同時進行的,但速度不會相等,因肉製品的品種、xingtaijiganzaogongyitiaojiandebutongeryouchabie。zaiganzhiguochengzhongyingtongguogongyitiaojiandekongzhihetiaojie,jinkenengshishuifenwaikuosanheneikuosandesuduxietiaohepingheng,ruguowaikuosansuduyuandayuneikuosan,jizaochengneibushuifenlaibujizhuanyidaobiaomian,yuanliaobiaomianhuiyinguoduganzaoerxingchengyingke(稱“結殼”現象),阻礙水分繼續蒸發,甚至出現表麵焦化和幹裂,降低產品質量。
ganzaoguochengzhong,ganzaosududekuaimanduiganzhipindepinzhiyoulieqizhejuedingxingdezuoyong。dangqitatiaojianxiangtongshi,ganzaosuduyukuai,chanpinyuburongyifashengbuliangbianhua,ganzhipinzhiliangjiuyuhao。yingxiangrouzhipinganzhideyinsuzhuyaoqujueyuyuanliaorouzhipinbiaomianji、溫度、濕度、空氣循環流動速度、大氣壓力和真空度以及幹燥時的裝載量等。
(一)肉製品表麵積
幹肉製品加工過程中,為了加速其濕熱交換,通常把經過預煮後的物料切分成小的片狀、條狀、粒li狀zhuang,再zai進jin行xing脫tuo水shui幹gan製zhi。物wu料liao切qie成cheng薄bo片pian或huo小xiao顆ke粒li後hou,縮suo短duan了le熱re量liang向xiang肉rou塊kuai中zhong心xin傳chuan遞di和he水shui分fen從cong肉rou塊kuai中zhong心xin外wai移yi的de距ju離li,增zeng加jia了le肉rou製zhi品pin和he加jia熱re介jie質zhi相xiang互hu接jie觸chu的de表biao麵mian積ji,縮suo短duan了le肉rou製zhi品pin內nei部bu水shui分fen外wai逸yi的de距ju離li,從cong而er加jia速su了le水shui分fen蒸zheng發fa和he肉rou製zhi品pin脫tuo水shui幹gan製zhi。因yin此ci,肉rou製zhi品pin的de表biao麵mian積ji越yue大da,其qi幹gan燥zao速su度du越yue快kuai。
(二)溫度
幹gan製zhi過guo程cheng中zhong,幹gan燥zao介jie質zhi和he肉rou製zhi品pin間jian溫wen差cha愈yu大da,熱re量liang向xiang肉rou製zhi品pin傳chuan遞di的de速su度du也ye愈yu快kuai,水shui分fen外wai逸yi速su度du亦yi加jia快kuai。在zai有you一yi定ding水shui蒸zheng氣qi含han量liang的de空kong氣qi中zhong,溫wen度du越yue高gao,達da到dao飽bao和he所suo需xu的de水shui蒸zheng氣qi越yue多duo,肉rou製zhi品pin幹gan燥zao速su度du也ye越yue快kuai;相反,溫度降低,達到飽和所需要的水蒸氣減少,幹燥速度降低。但溫度不能過高,否則會使肉製品焦化,降低商品價值。
(三)濕度
shiduduirouzhipinganzhisududeyingxiangzaiyuwendububian,ganzaojiezhishiduyuedi,kongqishidubaohechayueda,roupintuoshuisuduyuekuai。tigaowendu,tongfengpaishi,jiangdikongqishidu,kejiakuaituoshuisudu,shiganzaohourouzhipinhanshuiliangjiangdaoguobiaoguidingdefanwei。
(四)空氣循環流動速度
加jia速su空kong氣qi循xun環huan流liu動dong速su度du,不bu僅jin因yin熱re空kong氣qi所suo能neng容rong納na的de水shui蒸zheng氣qi量liang將jiang高gao於yu冷leng空kong氣qi而er吸xi收shou較jiao多duo的de蒸zheng發fa水shui分fen,還hai能neng及ji時shi將jiang聚ju積ji在zai肉rou製zhi品pin表biao麵mian附fu近jin的de飽bao和he濕shi空kong氣qi帶dai走zou,以yi免mian阻zu止zhi肉rou製zhi品pin中zhong所suo含han水shui分fen的de進jin一yi步bu蒸zheng發fa,同tong時shi還hai因yin和he肉rou製zhi品pin表biao麵mian接jie觸chu的de空kong氣qi量liang增zeng加jia,從cong而er顯xian著zhu加jia速su了le肉rou製zhi品pin中zhong水shui分fen的de蒸zheng發fa。但dan空kong氣qi的de循xun環huan流liu動dong速su度du不bu能neng過guo大da,防fang止zhi熱re能neng利li用yong不bu充chong分fen,增zeng加jia燃ran料liao的de消xiao耗hao。
(五)大氣壓力和真空度
水的沸點會隨著大氣壓力下降而降低,氣壓愈低,沸點愈低,因此肉品在幹製過程中所處環境的大氣壓力越低、真空度越高時,幹製過程就可以在較低的溫度下進行,幹燥速度愈快。
(六)裝載量
在(zai)一(yi)定(ding)的(de)單(dan)位(wei)麵(mian)積(ji)內(nei),所(suo)裝(zhuang)原(yuan)料(liao)量(liang)的(de)不(bu)同(tong),幹(gan)燥(zao)速(su)度(du)也(ye)不(bu)同(tong)。原(yuan)料(liao)的(de)裝(zhuang)載(zai)量(liang)通(tong)常(chang)與(yu)其(qi)厚(hou)度(du)密(mi)切(qie)相(xiang)關(guan),裝(zhuang)載(zai)量(liang)愈(yu)多(duo),厚(hou)度(du)愈(yu)大(da),愈(yu)不(bu)利(li)於(yu)空(kong)氣(qi)的(de)流(liu)通(tong),從(cong)而(er)影(ying)響(xiang)水(shui)分(fen)蒸(zheng)發(fa),因(yin)此(ci)幹(gan)製(zhi)過(guo)程(cheng)中(zhong)必(bi)須(xu)根(gen)據(ju)幹(gan)燥(zao)設(she)備(bei)的(de)規(gui)格(ge)確(que)定(ding)最(zui)佳(jia)的(de)原(yuan)料(liao)裝(zhuang)載(zai)量(liang)。
三、幹製方法
suizhekexuejishudebuduanfazhan,ganzhifangfadedaobuduandegaijinhetigao,ganzhishebeiyebuduangengxin。guinaqilai,rouzhipinganzhijiagongfangfazhuyaoyouliangzhong,jiziranganzhiherengongganzhi。
(一)自然幹製
自zi然ran幹gan製zhi是shi一yi種zhong古gu老lao的de幹gan燥zao方fang法fa,它ta是shi利li用yong自zi然ran條tiao件jian中zhong的de太tai陽yang輻fu射she和he幹gan燥zao空kong氣qi使shi肉rou製zhi品pin達da到dao幹gan燥zao的de一yi種zhong方fang法fa。自zi然ran幹gan製zhi可ke分fen為wei曬shai幹gan和he風feng幹gan兩liang種zhong類lei型xing。曬shai幹gan是shi指zhi將jiang原yuan料liao直zhi接jie置zhi於yu陽yang光guang下xia暴bao曬shai脫tuo水shui使shi其qi幹gan燥zao,其qi幹gan燥zao速su度du主zhu要yao受shou太tai陽yang輻fu射she強qiang度du的de影ying響xiang,太tai陽yang輻fu射she強qiang度du因yin地di區qu和he季ji節jie的de不bu同tong而er產chan生sheng差cha異yi,低di緯wei度du地di區qu比bi高gao緯wei度du地di區qu強qiang,夏xia、秋季比冬、春季強。風幹是指將原料放在通風良好的室內或棚下,使其自然風幹,其幹燥速度主要取決於環境的溫度、濕(shi)度(du)和(he)風(feng)速(su)。由(you)此(ci)可(ke)見(jian),自(zi)然(ran)幹(gan)製(zhi)要(yao)求(qiu)設(she)備(bei)簡(jian)單(dan),費(fei)用(yong)低(di),但(dan)受(shou)自(zi)然(ran)條(tiao)件(jian)的(de)限(xian)製(zhi),溫(wen)度(du)條(tiao)件(jian)很(hen)難(nan)控(kong)製(zhi),大(da)規(gui)模(mo)的(de)生(sheng)產(chan)很(hen)少(shao)采(cai)用(yong),隻(zhi)是(shi)在(zai)某(mou)些(xie)產(chan)品(pin)加(jia)工(gong)中(zhong)作(zuo)為(wei)輔(fu)助(zhu)工(gong)序(xu)采(cai)用(yong),如(ru)風(feng)幹(gan)香(xiang)腸(chang)的(de)幹(gan)製(zhi)等(deng)。
(二)人工幹製
rengongganzhishizhirengongkongzhigezhongganzaogongyitiaojiandeganzhifangfa。rengongganzhisuoxudeshebeitouzihehaonengfeiyongjiaoda,chengbenjiaogao,caozuoyebijiaofuza,danxiangduiyuziranganzhilaishuo,rengongganzhiyinrulegezhongxianjindeganzaoshebei,dadasuoduanleganzhishijian,ganzhitiaojianyiyukongzhi,ganzhichanpinpinzhijiaogao,shiroupinganzhidezhuyaofangxiang。muqianpubiancaiyongderengongganzhifangfayouhongchaoganzhi、烘房幹製、隧道幹製、帶式幹製,而遠紅外幹製、微波幹製、真空幹製、冷凍幹製等高新技術,也越來越廣泛應用。
1.烘炒幹製
烘炒幹製法亦稱傳導幹製。它是從最簡單的人工幹製設備——烘(hong)灶(zao)改(gai)良(liang)過(guo)來(lai)的(de),它(ta)依(yi)靠(kao)鍋(guo)壁(bi)等(deng)的(de)導(dao)熱(re)將(jiang)熱(re)量(liang)傳(chuan)給(gei)與(yu)壁(bi)接(jie)觸(chu)的(de)濕(shi)物(wu)料(liao),使(shi)其(qi)脫(tuo)水(shui)幹(gan)製(zhi),由(you)於(yu)濕(shi)物(wu)料(liao)與(yu)加(jia)熱(re)的(de)介(jie)質(zhi)不(bu)是(shi)直(zhi)接(jie)接(jie)觸(chu),所(suo)以(yi)這(zhe)種(zhong)方(fang)法(fa)又(you)稱(cheng)為(wei)間(jian)接(jie)加(jia)熱(re)幹(gan)燥(zao)。間(jian)接(jie)幹(gan)燥(zao)的(de)熱(re)源(yuan)可(ke)以(yi)是(shi)水(shui)蒸(zheng)氣(qi)、熱力、熱空氣等。這種幹製方法既可以在常溫下進行,也可以在真空下進行。如肉鬆加工過程中的炒鬆就是采用這種方法在常溫下進行的。
2.烘房幹製
烘房是采用煙道氣加熱的熱空氣對流式幹燥設備,具有幹燥容量大、幹燥速度快、生產能力高等特點,是目前我國中、xiaoxingxiangzhenqiyezuichangyongdeganzaoshebei。hongfangganzaofajiushizaihongfangzhongzhijieyigaowenderekongqiweireyuan,jiezhukongqiduiliujiangreliangchuangeishiwuliao。youyuzhezhongganzhifangfazhongshiwuliaoyujiaredejiezhifashengzhijiejiechu,guyouchengweizhijiejiareganzao。hongfangzhongderekongqijishirezaitiyoushishizaiti,zhezhongganzhifangfaduozaichangyaxiajinxing。yinweizaizhenkongganzaoqingkuangxia,youyuqixiangchuyudiya,reronglianghenxiao,bunengzhijieyikongqiweireyuan,bixucaiyongqitareyuan。hongfangzhongdeqiwentiaojiebijiaofangbian,buhuishiwuliaoguore,danrekongqilikaihongfangshi,rengdaiyouxiangdangdadereliang,yincihongfangganzaoduireliangdeliyonglvjiaodi。
3.隧道幹製
隧道幹製是將濕物料盛裝在載車內,載車沿軌道連續通過隧道使物料脫水幹燥。采用隧道幹製時,空氣的溫度、濕度和流速容易控製,幹燥時間短,品質好,生產效率高。
這種幹製方式是在一種連續式的熱空氣對流式幹燥設備——隧sui道dao式shi幹gan製zhi機ji中zhong完wan成cheng的de。隧sui道dao式shi幹gan製zhi機ji為wei金jin屬shu板ban製zhi成cheng的de長chang方fang體ti,由you加jia熱re間jian和he幹gan燥zao間jian組zu成cheng,加jia熱re間jian裝zhuang設she加jia熱re器qi和he鼓gu風feng機ji,將jiang熱re空kong氣qi送song入ru幹gan燥zao間jian,幹gan燥zao間jian為wei狹xia長chang的de隧sui道dao形xing,一yi般ban長chang為wei12~18m,寬約1.8m,高1.8~2.0m,底部設置軌道,需幹燥的原料盛放在載車內,沿軌道滑動脫水幹燥。隧道幹製按物料與熱空氣的運行方向,分為逆流式、順流式和混合式三種。
(1)逆流式幹製 物料載車的運行方向與熱空氣的流動方向相反,即物料由低溫高濕的一端進入,由高溫低濕的一端出來。原料幹燥的起始溫度較低(40~50℃),往前溫度逐漸升高,終了溫度達到最高(65~85℃)。
(2)順流式幹製 與前者相反,載車運行方向與熱空氣流動方向相同。物料從高溫(80~85℃)低濕的一端進入,水分蒸發很快,往前溫度逐漸降低,濕度漸高,水分蒸發減慢,終了時溫度較低(55~60℃)。這種幹製方法適合於肉幹這種幹製過程中需要變溫的物料的脫水幹製。
(3)混合式幹製 hunheshiganzhiyouchengduiliushiganzhi。zhezhongganzhishebeizhonganzhuanglelianggejiareqihelianggegufengji,fenbieshezaisuidaodeliangduan,refengyouliangduanchuixiangzhongjian,tongguoyuanliaohoujiangshirekongqicongsuidaozhongbujizhongpaichuyibufen,lingyibufenhuiliuliyong。zhuangyouwuliaodezaicheganzaoshi,wuliaoshouxianjinrushunliusuidao,yugaowen、快(kuai)速(su)的(de)熱(re)風(feng)相(xiang)遇(yu),水(shui)分(fen)大(da)量(liang)蒸(zheng)發(fa),載(zai)車(che)向(xiang)前(qian)行(xing)進(jin),溫(wen)度(du)漸(jian)低(di),濕(shi)度(du)較(jiao)高(gao),水(shui)分(fen)蒸(zheng)發(fa)速(su)度(du)漸(jian)緩(huan),不(bu)致(zhi)使(shi)物(wu)料(liao)表(biao)麵(mian)結(jie)成(cheng)硬(ying)殼(ke),待(dai)物(wu)料(liao)大(da)部(bu)分(fen)的(de)水(shui)分(fen)被(bei)排(pai)除(chu)後(hou),進(jin)入(ru)逆(ni)流(liu)隧(sui)道(dao),以(yi)後(hou)愈(yu)往(wang)前(qian)行(xing)進(jin),溫(wen)度(du)漸(jian)高(gao),濕(shi)度(du)漸(jian)低(di),製(zhi)品(pin)幹(gan)燥(zao)愈(yu)徹(che)底(di)。當(dang)物(wu)料(liao)進(jin)入(ru)逆(ni)流(liu)隧(sui)道(dao)後(hou),仍(reng)須(xu)控(kong)製(zhi)好(hao)空(kong)氣(qi)溫(wen)度(du),以(yi)免(mian)幹(gan)製(zhi)品(pin)焦(jiao)化(hua)變(bian)色(se)。
4.帶式幹製
帶dai式shi幹gan製zhi是shi將jiang濕shi物wu料liao放fang在zai運yun動dong的de鋼gang絲si網wang帶dai上shang,熱re空kong氣qi垂chui直zhi穿chuan流liu而er過guo帶dai走zou水shui分fen,使shi物wu料liao脫tuo水shui幹gan製zhi的de一yi種zhong方fang法fa。幹gan製zhi過guo程cheng中zhong濕shi物wu料liao放fang置zhi在zai最zui上shang層ceng鋼gang絲si網wang帶dai上shang,隨sui著zhe網wang帶dai的de移yi動dong,物wu料liao依yi次ci落luo入ru下xia一yi條tiao網wang帶dai,熱re空kong氣qi從cong下xia方fang引yin入ru,由you下xia而er上shang進jin到dao網wang帶dai上shang方fang,濕shi熱re空kong氣qi由you上shang部bu排pai氣qi口kou排pai出chu,最zui後hou幹gan物wu料liao從cong下xia部bu卸xie出chu。在zai這zhe種zhong幹gan製zhi方fang法fa中zhong物wu料liao自zi上shang層ceng向xiang下xia層ceng落luo下xia時shi即ji自zi動dong翻fan動dong一yi次ci,因yin而er幹gan燥zao較jiao均jun勻yun。
5.遠紅外幹製
遠(yuan)紅(hong)外(wai)幹(gan)製(zhi)是(shi)指(zhi)利(li)用(yong)安(an)裝(zhuang)在(zai)幹(gan)燥(zao)室(shi)內(nei)的(de)輻(fu)射(she)元(yuan)件(jian)發(fa)出(chu)遠(yuan)紅(hong)外(wai)線(xian),被(bei)物(wu)料(liao)吸(xi)收(shou)轉(zhuan)變(bian)為(wei)熱(re)能(neng)從(cong)而(er)達(da)到(dao)脫(tuo)水(shui)幹(gan)製(zhi)的(de)方(fang)法(fa)。紅(hong)外(wai)線(xian)是(shi)介(jie)於(yu)可(ke)見(jian)光(guang)與(yu)微(wei)波(bo)間(jian)的(de)電(dian)磁(ci)波(bo),波(bo)長(chang)0.75~1000μm,其中40~1000μm波段稱為遠紅外線,遠紅外線和可見光一樣,照射到物料表麵時可被吸收、折射和反射,被吸收的部分則轉化為熱能,使物料溫度升高。它還有很強的穿透力,可使物料內、外部均受熱。因此遠紅外幹製具有幹燥速度快、效率高、品質好、節能等特點。
6.微波幹製
用(yong)上(shang)述(shu)幹(gan)製(zhi)方(fang)法(fa)幹(gan)製(zhi)肉(rou)品(pin)時(shi),熱(re)能(neng)都(dou)是(shi)從(cong)物(wu)料(liao)表(biao)麵(mian)傳(chuan)至(zhi)內(nei)部(bu),物(wu)料(liao)表(biao)麵(mian)溫(wen)度(du)比(bi)內(nei)部(bu)高(gao),而(er)水(shui)分(fen)是(shi)從(cong)內(nei)部(bu)擴(kuo)散(san)至(zhi)表(biao)麵(mian),在(zai)幹(gan)燥(zao)過(guo)程(cheng)中(zhong)物(wu)料(liao)表(biao)麵(mian)先(xian)變(bian)成(cheng)幹(gan)燥(zao)固(gu)體(ti)的(de)絕(jue)熱(re)層(ceng),使(shi)傳(chuan)熱(re)和(he)內(nei)部(bu)水(shui)分(fen)的(de)汽(qi)化(hua)及(ji)擴(kuo)散(san)增(zeng)加(jia)阻(zu)力(li)的(de),故(gu)幹(gan)燥(zao)的(de)時(shi)間(jian)較(jiao)長(chang),且(qie)易(yi)造(zao)成(cheng)外(wai)焦(jiao)內(nei)濕(shi)現(xian)象(xiang)。利(li)用(yong)新(xin)型(xing)微(wei)波(bo)幹(gan)製(zhi)方(fang)法(fa)則(ze)可(ke)有(you)效(xiao)地(di)解(jie)決(jue)以(yi)上(shang)問(wen)題(ti)。微(wei)波(bo)電(dian)子(zi)管(guan)可(ke)發(fa)出(chu)頻(pin)率(lv)為(wei)300~300000MHz、波長為0.001~1.0m、介(jie)於(yu)無(wu)線(xian)電(dian)波(bo)與(yu)光(guang)波(bo)之(zhi)間(jian)的(de)超(chao)高(gao)頻(pin)電(dian)磁(ci)波(bo),這(zhe)種(zhong)超(chao)高(gao)頻(pin)電(dian)磁(ci)波(bo)形(xing)成(cheng)帶(dai)有(you)正(zheng)負(fu)極(ji)的(de)呈(cheng)現(xian)波(bo)浪(lang)性(xing)變(bian)化(hua)的(de)電(dian)場(chang)。物(wu)料(liao)中(zhong)有(you)大(da)量(liang)的(de)帶(dai)正(zheng)負(fu)電(dian)荷(he)的(de)分(fen)子(zi)(水、鹽、糖)zaiweiboxingchengdedianchangzuoyongxia,daifudianhedefenzixiangdianchangdezhengjiyundong,daizhengdianhedefenzixiangdianchangfujiyundong。fenzijiandeyundongchanshengdaliangdereliang,shiwuliaodeyiganzao,suiranweibopinlvcong300MHz到300000MHz,但實際上並不能在這個範圍內任取頻率,因為此頻帶內包括了廣播、通訊雷達用的頻率,所以國際上規定工業用的頻率隻有915MHz和2450MHz兩個頻帶。微波的穿透能力極強,並能在物料內外同時產生,且無須熱傳導、輻射、對dui流liu,在zai短duan時shi內nei即ji可ke達da到dao幹gan燥zao的de目mu的de。物wu料liao內nei外wai受shou熱re均jun勻yun,表biao麵mian不bu易yi焦jiao糊hu。但dan微wei波bo幹gan燥zao設she備bei投tou資zi費fei用yong較jiao高gao,幹gan肉rou製zhi品pin的de特te征zheng性xing風feng味wei和he色se澤ze不bu明ming顯xian。
7.真空幹製
zhenkongganzhiyouchengjianyaganzhi,shuidefeidiansuiyalijiangdierjiangdi,zaizhenkongtiaojianxia,caiyongjiaodidewendujiunengjiangwuliaodeshuifentuochu,dadaoganzhidemude。zhenkongganzaoshi,zhenkongbengjiangganzaoshichouchengzhenkong,liyongzhengqitongrujiarebanduiwuliaojinxingjiare,zaizhenkongzhuangtaixia,wuliaoshuifendeneibukuosanyuwaibuzhengfagongtongjinxingganzao。yinci,yuchangyaganzhifangfaxiangbi,zhenkongganzhijuyouganzaoshijianduan、表麵硬化小等優點;但幹燥過程中因蒸發而導致物料芳香成分的逸失及輕微的熱變性也不可避免。
8.冷凍幹製
lengdongganzhiyouchenglengdongshenghuaganzao,tashijiangwuliaokuaisudongjiedaobingdianyixia,shishuifenbianchenggutaidebing,ranhouzaijiaogaodezhenkongzhuangtaixia,shibingbujingyetaizhijieshenghuachengshuizhengqierjinxingtuoshuiganzao。zhezhongganzaofangfaduise、味、香、xingjihuwurenhebuliangyingxiang,shixiandaizuixianjindeganzaofangfa。muqian,woguolengdongganzaofazaiganrouzhipinjiagongzhongdeyingyongcaiqibu,xiangxinhuidedaoxunsufazhan。qicaozuofangfashi:將肉塊急速冷凍至-40~-30℃,並將其置於真空度為13~133Pa的(de)幹(gan)燥(zao)室(shi)中(zhong),在(zai)這(zhe)種(zhong)狀(zhuang)態(tai)下(xia)肉(rou)塊(kuai)的(de)冰(bing)直(zhi)接(jie)升(sheng)華(hua)成(cheng)水(shui)蒸(zheng)氣(qi)而(er)進(jin)行(xing)幹(gan)燥(zao)。采(cai)用(yong)冷(leng)凍(dong)幹(gan)燥(zao)的(de)肉(rou)塊(kuai)體(ti)積(ji)不(bu)變(bian),內(nei)部(bu)組(zu)織(zhi)呈(cheng)疏(shu)鬆(song)多(duo)孔(kong)狀(zhuang)態(tai),具(ju)有(you)很(hen)好(hao)的(de)複(fu)水(shui)性(xing),是(shi)方(fang)便(bian)麵(mian)等(deng)速(su)食(shi)品(pin)的(de)理(li)想(xiang)輔(fu)料(liao)。因(yin)此(ci),采(cai)用(yong)冷(leng)凍(dong)幹(gan)燥(zao)的(de)肉(rou)塊(kuai)在(zai)貯(zhu)藏(zang)過(guo)程(cheng)中(zhong)也(ye)非(fei)常(chang)容(rong)易(yi)吸(xi)水(shui),且(qie)其(qi)疏(shu)鬆(song)多(duo)孔(kong)狀(zhuang)態(tai)與(yu)空(kong)氣(qi)接(jie)觸(chu)麵(mian)積(ji)增(zeng)大(da),在(zai)貯(zhu)藏(zang)期(qi)間(jian)易(yi)被(bei)氧(yang)化(hua)變(bian)質(zhi),特(te)別(bie)是(shi)脂(zhi)肪(fang)含(han)量(liang)高(gao)的(de)物(wu)料(liao)。
此外,人工幹製方法還有噴霧幹製、輻射幹製、介電加熱幹製等,由於這些幹製方法在肉類幹製品加工中很少使用,故此處不作介紹。
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