Lub Luag Haujlwm ntawm Cov Kab Mob hauv Cov Txheej Txheem Fermentation
Kev ua kom cov khoom noj muaj kua qaub (fermentation) yog ib qho ntawm cov thev naus laus zis qub tshaj plaws uas tib neeg siv los ua, khaws cia, thiab txhim kho qhov saj ntawm cov khoom noj. Cov txheej txheem no siv cov haujlwm ntawm cov kab mob me me—feem ntau yog cov kab mob me me thiab cov poov xab—los hloov cov tshuaj lom neeg hauv cov khoom noj mus rau hauv cov tshuaj tshiab uas ruaj khov dua, muaj kev nyab xeeb dua, lossis qab dua. Ntawm ntau yam kab mob me me uas koom nrog, cov kab mob me me ua lub luag haujlwm tseem ceeb vim lawv muaj peev xwm tsim cov kua qaub, qee yam cawv, cov pa roj, thiab cov tshuaj tsw qab sib txawv. Lub luag haujlwm ntawm cov kab mob me me hauv kev ua kom cov khoom noj muaj kua qaub tsis yog tsuas yog cuam tshuam rau saj thiab cov qauv xwb tab sis kuj cuam tshuam rau cov txiaj ntsig ntawm kev noj qab haus huv, kev nyab xeeb ntawm cov khoom noj, thiab txawm tias cov txiaj ntsig kev noj qab haus huv.
To taub txog kev ua kom lub cev tsis muaj zog thiab nws txoj kev sib raug zoo rau cov kab mob
Hais yooj yim xwb, kev ua kom cov khoom noj muaj roj (fermentation) yog ib qho txheej txheem uas cov kab mob me me hloov cov suab thaj lossis lwm yam carbohydrates mus ua cov kua qaub, cov pa roj, lossis cov cawv nyob rau hauv cov xwm txheej tshwj xeeb, feem ntau nrog cov pa oxygen tsawg. Hauv ntau yam khoom noj uas tau ua kom cov khoom noj muaj roj, cov kab mob ua haujlwm los ntawm kev rhuav tshem cov piam thaj thiab tsim cov kua qaub lactic, acetic acid, lossis lwm yam tshuaj. Cov khoom seem no yog cov uas ua rau cov mis nyuj qaub lossis txiv lws suav muaj saj qab, lawv cov ntxhiab tsw tshwj xeeb, thiab lawv lub sijhawm khaws cia ntev.
Cov kab mob uas feem ntau koom nrog hauv kev ua kom cov kua txiv hmab txiv ntoo yog cov kab mob lactic acid (LAB), xws li Lactobacillus, Streptococcus, Leuconostoc, thiab Pediococcus. Tsis tas li ntawd, cov kab mob acetic acid, xws li Acetobacter, yog qhov tseem ceeb hauv kev tsim cov kua txiv hmab txiv ntoo. Txhua pawg kab mob muaj txoj hauv kev ua kom cov khoom noj khoom haus sib txawv, ua rau muaj ntau yam ntxwv ntawm cov khoom noj khoom haus.
Cov kab mob ua "Cov Tshuaj Tiv Thaiv Ntuj" los ntawm Kev Tsim Cov Kua Txob
Ib qho ntawm cov luag haujlwm tseem ceeb tshaj plaws ntawm cov kab mob hauv kev fermentation yog tsim cov kua qaub uas txo qis pH ntawm cov khoom noj. Thaum pH poob qis, ntau cov kab mob lwj thiab cov kab mob pathogenic muaj teeb meem kom loj hlob. Piv txwv li, cov kab mob lactic acid hloov cov suab thaj mus rau hauv lactic acid, tsim ib puag ncig acidic uas tiv thaiv cov kab mob phem xws li Salmonella lossis Escherichia coli (txawm hais tias kev nyab xeeb tseem nyob ntawm kev tu cev huv thiab kev ua kom raug).
Ib qho piv txwv tseeb yog kev tsim cov kimchi, sauerkraut, thiab pickles. Hauv cov txheej txheem no, cov kab mob lactic acid maj mam tsim: thaum pib ntawm kev fermentation, cov kab mob ntsev thiab oxygen-tolerant pib cov txheej txheem, tom qab ntawd ntau cov kab mob acid-tolerant yuav siv thaum pH txo qis. Qhov tshwm sim yog cov khoom uas muaj lub sijhawm khaws cia ntev dua, muaj qhov saj qaub tshwj xeeb, thiab tseem muaj kev nyab xeeb rau kev noj thaum npaj siv cov txheej txheem raug.
Tsim kom muaj qhov tsw thiab aroma tshwj xeeb
Cov kab mob tsis yog tsuas yog "ua kom cov zaub mov muaj kua qaub xwb, tab sis kuj tsim cov qauv saj thiab aroma sib txawv. Thaum lub sijhawm fermentation, cov kab mob tsim ntau yam tshuaj volatile xws li diacetyl (muab ib qho aroma butter), acetaldehyde, organic acids, thiab lwm yam tshuaj uas pab ua rau muaj saj.
Hauv cov khoom noj mis nyuj uas muaj fermented xws li yogurt, lub luag haujlwm ntawm cov kab mob yog qhov pom tseeb tshwj xeeb. Kev sib xyaw ua ke ntawm Streptococcus thermophilus thiab Lactobacillus delbrueckii subsp. bulgaricus tsim cov lactic acid, uas muab cov saj tshiab, nrog rau cov aroma compounds uas muab cov yogurt nws cov saj tshwj xeeb. Hauv cheese, cov kab mob pib thiab cov kab mob ripening ua haujlwm los ua kom cov saj tob dua; qee qhov tsim cov pa roj uas tsim "qhov muag" hauv qee cov cheese, thaum lwm tus pab tsim cov aroma ntse lossis savory.
Kev Hloov Cov Qauv thiab Cov Qauv ntawm Cov Khoom Noj
Lub luag haujlwm ntawm cov kab mob kuj txiav txim siab qhov zoo ntawm cov khoom noj uas tau fermented. Hauv cov mis nyuj yogurt, cov kua qaub uas cov kab mob tsim tawm ua rau cov protein mis nyuj (casein) coagulate ua ib lub gel, ua rau muaj cov qauv tuab. Hauv qee qhov kev fermentations, cov kab mob tsim cov extracellular polysaccharides (EPS), uas tuaj yeem ua rau kom viscosity thiab muab qhov ncauj du.
Hauv cov zaub uas tau fermented, cov kab mob pab tswj kom cov zaub no crispy los ntawm kev tsim cov kua qaub ruaj khov thiab tswj cov haujlwm ntawm qee cov enzymes uas ua rau lwj. Txawm li cas los xij, yog tias tsis tswj kev fermentation (piv txwv li, yog tias qhov kub siab dhau lossis cov ntsev tsis raug), cov qauv tuaj yeem mos dhau vim muaj cov kab mob tsis zoo.
Kev Ua Kom Muaj Cov Khoom Noj Muaj Nqis Thiab Muaj Cov Khoom Noj Muaj Quav Ntau Ntxiv
Feem ntau cov kab mob bacteria ua rau cov khoom noj muaj txiaj ntsig zoo dua. Muaj ntau txoj hauv kev koom nrog. Ua ntej, cov kab mob bacteria tuaj yeem rhuav cov khoom sib xyaw ua ke kom yooj yim zom. Piv txwv li, hauv cov khoom mis nyuj fermented, qee cov lactose raug rhuav tshem, ua rau cov mis nyuj yogurt feem ntau zoo dua rau cov neeg uas muaj kev tsis haum lactose dua li cov mis nyuj tshiab.
Qhov thib ob, kev ua kom cov khoom noj tsis muaj txiaj ntsig (antinutrients). Qee cov khoom xyaw uas ua los ntawm cov nroj tsuag muaj cov tshuaj xws li phytates, uas khi cov zaub mov (hlau, zinc, calcium), ua rau lawv nyuaj rau lub cev nqus tau. Kev ua haujlwm ntawm cov kab mob me me thaum lub sijhawm ua kom cov zaub mov muaj ntau dua. Qhov thib peb, qee cov kab mob muaj peev xwm tsim cov vitamins, tshwj xeeb tshaj yog cov vitamins B, ntau yam nyob ntawm hom khoom thiab cov kab lis kev cai siv.
Tswj Kev Nyab Xeeb Khoom Noj los ntawm Cov Tshuaj Tua Kab Mob
Ntxiv rau qhov txo qis pH, cov kab mob lactic acid tuaj yeem tsim lwm cov tshuaj tua kab mob xws li hydrogen peroxide, acetic acid, thiab bacteriocins. Bacteriocins yog cov protein lossis peptides tua kab mob uas tuaj yeem tiv thaiv kev loj hlob ntawm lwm cov kab mob. Qhov muaj cov tshuaj no ua rau cov nyhuv tiv thaiv ntuj tsim ntxiv.
Hauv kev lag luam khoom noj, qee cov kab mob bacterial raug xaiv tsis yog vim lawv muaj peev xwm tsim cov saj zoo xwb, tab sis kuj vim lawv muaj peev xwm tswj cov kab mob phem. Qhov no yog ib qho laj thawj vim li cas kev siv "cov kab mob pib" tseem ceeb: nws tso cai rau kev fermentation zoo dua, txo qhov kev pheej hmoo ntawm kev ua tsis tiav, thiab txhim kho kev nyab xeeb.
Piv txwv ntawm Cov Khoom Noj Uas Muaj Cov Kab Mob Fermented
Ntau yam khoom noj thiab dej haus txhua hnub nyob ntawm cov kab mob, xws li cov neeg ua yeeb yam tseem ceeb lossis ua haujlwm nrog cov poov xab:
1. Mis nyuj qaub: kev ua kom cov lactose los ntawm cov kab mob lactic acid tsim cov lactic acid, tsim cov qauv tuab thiab cov saj qaub tshiab.
2. Cheese: cov kab mob pib pib ua kom acidification; lwm cov kab mob koom nrog kev siav kom tsim cov saj thiab aroma.
3. Kimchi thiab sauerkraut: cov kab mob lactic acid feem ntau tom qab theem pib, tsim kom muaj saj qaub, tsw qab tshwj xeeb, thiab lub sijhawm khaws cia ntev dua.
4. Kev ntxuav: kev ua kom cov kab mob zoo loj hlob hauv cov kua ntsev uas khaws cov khoom xyaw.
5. Kua txiv qaub: cov kab mob acetic acid hloov cov cawv mus ua acetic acid, ua rau muaj qhov saj ntse thiab qaub ntawm cov kua txiv qaub.
6. Nata de coco: muaj cov kab mob uas tsim cov cellulose, tsim cov qauv mos ntawm nata.
Cov piv txwv no qhia tau hais tias cov kab mob tsis yog tsuas yog ua lub luag haujlwm hauv ib hom khoom siv xwb, tab sis kuj hla cov khoom muag: mis nyuj, zaub, txiv hmab txiv ntoo, thiab txawm tias cov kua qab zib.
Cov Yam Cuam Tshuam Rau Kev Ua Haujlwm ntawm Cov Kab Mob hauv Kev Ua Kom Fermentation
Kev vam meej ntawm kev fermentation yog cuam tshuam los ntawm cov xwm txheej ib puag ncig uas txiav txim siab qhov kev loj hlob ntawm cov kab mob, suav nrog:
– Kub: Txhua tus kab mob muaj qhov kub zoo tshaj plaws. Piv txwv li, mis nyuj qaub feem ntau ferment ntawm qhov kub sov, thaum zaub ferment feem ntau tshwm sim ntawm qhov kub qis dua hauv chav.
– Cov ntsev muaj pes tsawg: thaum ua zaub mov, ntsev pab rub dej thiab tswj cov kab mob uas ua rau lwj, thiab tseem muab qhov zoo dua rau cov kab mob lactic acid.
– Muaj qab zib: cov kab mob xav tau lub zog; cov ntaub ntawv uas muaj qab zib tsawg qee zaum xav tau kev kho tshwj xeeb rau kev ua kom fermentation zoo.
– Kev huv thiab pa oxygen: Kev tu cev tsis zoo tuaj yeem ua rau muaj cov kab mob tsis xav tau. Qee qhov kev ua kom fermentation xav tau cov xwm txheej anaerobic (tsawg oxygen), yog li cov thawv thiab cov txheej txheem khaws cia yog qhov tseem ceeb.
Kev nkag siab txog cov yam no pab cov neeg tsim khoom hauv tsev thiab cov neeg ua lag luam tsim cov khoom fermented uas ruaj khov thiab muaj kev nyab xeeb.
Kev kaw
Cov kab mob ua lub luag haujlwm tseem ceeb hauv cov txheej txheem fermentation: khaws cov khoom noj los ntawm kev txo qis pH, tsim cov saj thiab aromas sib txawv, txhim kho cov qauv, ua kom muaj cov as-ham ntau ntxiv, thiab pab tswj kev nyab xeeb ntawm cov khoom noj los ntawm kev tsim cov tshuaj tua kab mob. Los ntawm kev xaiv cov kab mob zoo thiab tswj cov xwm txheej fermentation - xws li qhov kub, ntsev, thiab kev tu cev - peb tuaj yeem siv fermentation ua ib txoj hauv kev ntuj los tsim cov khoom noj qab, muaj txiaj ntsig zoo, thiab kav ntev. Nws tsis yog qhov ua kom hais tias ntau ntawm cov cuab yeej cuab tam ua noj ua haus hauv ntiaj teb, suav nrog cov khoom lag luam ib txwm muaj los ntawm ntau thaj chaw, yog tsim los ntawm cov haujlwm me me tab sis zoo kawg nkaus ntawm cov kab mob fermenting.
