1白濁現象的產生及其原因
tangshuijuziguantoudebaizhuoxianxiang,shizhizhiyechuxianhunzhuo,yanzhongshichanshengchendian,jubanbeibushanangbingchuyoubaidianxichu。zhexiebaisehunzhuochendianwuzhuyaochengfenshijupigan,tayuezhanhunzhuowuzhide57%左右,其次是果膠及少量的蛋白質。桔皮苷、果膠在桔皮桔絡中含量最多,其次為瓤囊內、外皮及砂囊中,果汁中較少。桔皮苷為柑桔類果實苦味的來源,含量隨品種及成熟程度而異。
桔皮苷在稀酸中加熱或隨著果實的成熟,逐漸起水解作用,生成桔皮素、葡萄糖和鼠李糖:
C28H34O15+2H2O→C16H14O6+C6H12O6+C6H12O5
桔皮苷桔皮素葡萄糖鼠李糖
桔皮苷難溶於水,而易溶於酒精及堿液中。溶於堿液中呈黃色,溶解度隨著溫度和PH值的增高而加大。但這兩種作用是可逆的,pH值及溫度逐漸降低時,溶解了的桔皮苷就生成白色沉澱析出。在pH4時(shi),其(qi)溶(rong)解(jie)度(du)最(zui)小(xiao)。析(xi)出(chu)的(de)沉(chen)澱(dian)在(zai)顯(xian)微(wei)鏡(jing)下(xia)呈(cheng)針(zhen)狀(zhuang)結(jie)晶(jing),它(ta)在(zai)冷(leng)水(shui)中(zhong)溶(rong)解(jie)度(du)極(ji)低(di)。罐(guan)頭(tou)中(zhong)出(chu)現(xian)的(de)這(zhe)種(zhong)沉(chen)澱(dian)常(chang)常(chang)呈(cheng)白(bai)色(se)混(hun)濁(zhuo)狀(zhuang)態(tai),這(zhe)是(shi)因(yin)為(wei)汁(zhi)液(ye)中(zhong)含(han)有(you)果(guo)膠(jiao)所(suo)致(zhi)。據(ju)研(yan)究(jiu),罐(guan)頭(tou)糖(tang)液(ye)中(zhong)桔(ju)皮(pi)苷(gan)的(de)溶(rong)解(jie)度(du)隨(sui)貯(zhu)藏(zang)時(shi)間(jian)而(er)異(yi),約(yue)在(zai)12~20mg%之間,當溶液中含量超過時,就會析出結晶,從而降低了糖液的透明度。
yibaneryan,jingguobaowenzhuzanghoudetangshuijuziguantou,suizhekuwendejiangdi,yirongjiedejupigansuitangyewendudejiangdierzhujianjiejingxichu,yuzhiyezhongdeguojiaojiehechengxixiaokeli,bianhuichanshengbaisehunzhuoxianxiangshenzhichendian。ciwai,tangshuijuziguantouchanshengbaizhuoxianxiangdezhuyaoyuanyinhaiyou:
1.1沒有選擇優良的原料品種
rushangsuoshu,guantouzhongdebaisechendianwushiyouguorouzhongdejupigannanrongyushuierzaitangyezhongxichujiejingsuozhi。youguanziliaobiaoming,butongdeganjupinzhong,qijupigandehanliangyebuxiangtong。ruwenzhoumigandejupiganhanliangjiufeichangshao,huangyanbendizaohesichuanfujudejupiganhanliangzexiangduiduoyidian,erluganhejiaogandejupiganhanliangweizuiduo。lingwai,tongyipinzhongdejupiganhanliangyouyuqihou、土壤及成熟度種植條件等各種因素有密切關係,成熟度越低的桔子,製成糖水罐頭後,其沉澱也越嚴重。
2.2原輔料的處理不妥當
在糖水罐頭加工過程中,對原輔料處理不妥,如糖液過濾不盡,本身含有雜質;桔瓣破裂過多,砂瓤外散,同時流出的汁液在高溫殺菌時因膠體凝聚而出現沉澱;堿液去皮不夠,囊衣中的桔皮苷在酸性糖液中溶解度極小而發生白色沉澱。
3.3加工用水硬度過高
當桔子罐頭加工用水硬度過高,水中的鈣、鎂離子與桔瓣及糖液中的有機酸結合生成不溶性的鈣和鎂鹽沉澱,使糖液混濁不清。
3.4生產中吸入汙濁冷卻水
由you於yu罐guan頭tou在zai封feng蓋gai時shi不bu嚴yan,在zai高gao溫wen殺sha菌jun中zhong,罐guan蓋gai內nei橡xiang膠jiao圈quan直zhi接jie遇yu高gao溫wen沸fei水shui而er軟ruan化hua,至zhi罐guan頭tou冷leng卻que時shi,罐guan中zhong內nei容rong物wu因yin溫wen度du下xia降jiang而er收shou縮suo,形xing成cheng一yi定ding的de真zhen空kong度du,從cong而er因yin外wai壓ya高gao於yu內nei壓ya而er從cong橡xiang膠jiao軟ruan化hua處chu吸xi入ru汙wu濁zhuo的de冷leng卻que水shui,形xing成cheng汙wu染ran糖tang液ye的de“濁源”,如果吸入量較多,3~4天內就會出現明顯的混濁,嚴重時會導致整個罐頭糖液模糊不清。
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