水果、蔬菜的保鮮與許多因素,如溫度、濕度、氣(qi)體(ti)成(cheng)分(fen)等(deng)有(you)關(guan),這(zhe)裏(li)講(jiang)的(de)保(bao)鮮(xian)包(bao)裝(zhuang)主(zhu)要(yao)是(shi)指(zhi)在(zai)常(chang)溫(wen)條(tiao)件(jian)下(xia)如(ru)何(he)保(bao)鮮(xian)。果(guo)蔬(shu)的(de)常(chang)溫(wen)保(bao)鮮(xian)包(bao)裝(zhuang)主(zhu)要(yao)是(shi)控(kong)製(zhi)氣(qi)體(ti)成(cheng)分(fen)和(he)濕(shi)度(du)以(yi)及(ji)合(he)適(shi)的(de)緩(huan)衝(chong)包(bao)裝(zhuang),再(zai)加(jia)上(shang)適(shi)量(liang)的(de)保(bao)鮮(xian)劑(ji)構(gou)成(cheng)。
(1)果蔬的小包裝保鮮法,果蔬的小包裝一般是指單個包裝,常用的保鮮法有以下兩種:
①保(bao)鮮(xian)薄(bo)膜(mo)包(bao)裝(zhuang)。保(bao)鮮(xian)薄(bo)膜(mo)是(shi)一(yi)種(zhong)塑(su)料(liao)薄(bo)膜(mo),這(zhe)種(zhong)薄(bo)膜(mo)幾(ji)乎(hu)不(bu)透(tou)水(shui),而(er)氧(yang)氣(qi)和(he)二(er)氧(yang)化(hua)碳(tan)卻(que)較(jiao)易(yi)通(tong)過(guo),用(yong)這(zhe)種(zhong)性(xing)能(neng)獨(du)特(te)的(de)保(bao)鮮(xian)薄(bo)膜(mo)進(jin)行(xing)果(guo)蔬(shu)的(de)單(dan)個(ge)包(bao)裝(zhuang)時(shi),包(bao)裝(zhuang)袋(dai)內(nei)處(chu)於(yu)一(yi)種(zhong)有(you)利(li)於(yu)果(guo)蔬(shu)保(bao)鮮(xian)的(de)微(wei)氣(qi)候(hou),由(you)於(yu)這(zhe)種(zhong)薄(bo)膜(mo)對(dui)氧(yang)氣(qi)和(he)二(er)氧(yang)化(hua)碳(tan)有(you)適(shi)度(du)的(de)透(tou)過(guo)性(xing),能(neng)自(zi)動(dong)調(tiao)節(jie)包(bao)裝(zhuang)袋(dai)內(nei)氧(yang)與(yu)二(er)氧(yang)化(hua)碳(tan)濃(nong)度(du),使(shi)其(qi)濃(nong)度(du)既(ji)能(neng)抑(yi)製(zhi)果(guo)蔬(shu)的(de)呼(hu)吸(xi)作(zuo)用(yong),又(you)不(bu)致(zhi)損(sun)害(hai)果(guo)蔬(shu)品(pin)質(zhi)。一(yi)般(ban)適(shi)合(he)保(bao)鮮(xian)的(de)氧(yang)氣(qi)濃(nong)度(du)為(wei)1~6%,二氧化碳濃度為1~10%。這種薄膜由於幾乎不透水,使袋內相對濕度增大,可防止果蔬因水分過度蒸發而幹縮。常用的保鮮薄膜有聚乙烯、聚丙烯、聚氯乙烯、聚偏二氯乙烯等薄膜。
②保bao鮮xian劑ji保bao鮮xian。保bao鮮xian劑ji可ke延yan緩huan果guo蔬shu的de生sheng命ming活huo動dong,使shi果guo蔬shu得de以yi保bao鮮xian。保bao鮮xian劑ji分fen固gu體ti和he液ye體ti兩liang類lei。小xiao包bao裝zhuang多duo用yong液ye體ti保bao鮮xian劑ji。使shi用yong時shi,將jiang水shui果guo浸jin入ru這zhe種zhong浸jin塗tu液ye中zhong,爾er後hou取qu出chu幹gan燥zao,水shui果guo表biao麵mian便bian形xing成cheng一yi層ceng可ke食shi的de極ji薄bo保bao護hu膜mo,能neng堵du塞sai果guo皮pi表biao麵mian的de氣qi孔kong,減jian弱ruo呼hu吸xi作zuo用yong而er保bao鮮xian。此ci法fa一yi般ban用yong於yu水shui果guo。
(2)果蔬的外包裝,外(wai)包(bao)裝(zhuang)又(you)稱(cheng)大(da)包(bao)裝(zhuang),是(shi)將(jiang)一(yi)定(ding)數(shu)量(liang)的(de)果(guo)蔬(shu)置(zhi)於(yu)一(yi)個(ge)包(bao)裝(zhuang)內(nei)。保(bao)鮮(xian)容(rong)器(qi)保(bao)鮮(xian)。保(bao)鮮(xian)容(rong)器(qi)是(shi)具(ju)有(you)保(bao)鮮(xian)性(xing)能(neng)的(de)容(rong)器(qi)。可(ke)在(zai)瓦(wa)楞(leng)紙(zhi)中(zhong)夾(jia)一(yi)層(ceng)聚(ju)乙(yi)烯(xi)等(deng)保(bao)鮮(xian)薄(bo)膜(mo),再(zai)製(zhi)成(cheng)紙(zhi)箱(xiang);也(ye)可(ke)在(zai)紙(zhi)箱(xiang)上(shang)塗(tu)布(bu)聚(ju)乙(yi)烯(xi)類(lei)塗(tu)料(liao),塑(su)料(liao)有(you)選(xuan)擇(ze)的(de)阻(zu)隔(ge)性(xing)能(neng)使(shi)其(qi)內(nei)處(chu)在(zai)有(you)利(li)於(yu)果(guo)蔬(shu)保(bao)鮮(xian)的(de)微(wei)氣(qi)候(hou)中(zhong),紙(zhi)箱(xiang)良(liang)好(hao)的(de)隔(ge)熱(re)性(xing)可(ke)保(bao)持(chi)箱(xiang)內(nei)一(yi)定(ding)的(de)溫(wen)度(du)和(he)濕(shi)度(du)。還(hai)可(ke)以(yi)設(she)計(ji)一(yi)種(zhong)人(ren)造(zao)氣(qi)窗(chuang)包(bao)裝(zhuang)容(rong)器(qi),這(zhe)是(shi)在(zai)密(mi)封(feng)容(rong)器(qi)上(shang)開(kai)一(yi)個(ge)氣(qi)窗(chuang),開(kai)窗(chuang)部(bu)位(wei)用(yong)“人工肺”薄bo膜mo覆fu蓋gai,這zhe種zhong薄bo膜mo是shi用yong尼ni龍long纖xian維wei布bu浸jin於yu矽gui氧yang烷wan混hun合he液ye後hou,幹gan燥zao而er成cheng,有you如ru肺fei一yi樣yang,有you良liang好hao的de調tiao節jie氧yang氣qi濃nong度du,抑yi製zhi呼hu吸xi作zuo用yong的de功gong能neng,保bao鮮xian效xiao果guo很hen好hao。
另外,還可在包裝容器內加適量的固體保鮮劑,它以沸石、膨潤土、活性炭、qingyanghuagaidengzhicheng,shijishiyizhongxifuji,kexishouguoshusanfaderuyixidengqitiwuzhi,congeryanhuanqihoushuguocheng。yongshijiangqizhuangrutouqixiaodai,fengkouhouzaizhiyubaozhuangnei。
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