Cov Txheej Txheem Fermentation hauv Microorganisms
Kev ua kom lub cev zom zaub mov yog ib qho ntawm cov txheej txheem tseem ceeb tshaj plaws uas cov kab mob me me ua kom tau lub zog. Cov txheej txheem no tau siv los ntawm tib neeg rau ntau txhiab xyoo, ntev ua ntej lub tswv yim ntawm microbiology tau lees paub los ntawm kev tshawb fawb. Ntau yam khoom noj thiab dej haus xws li tempeh, yogurt, mov ci, fermented cassava, kua ntses taum pauv, kimchi, thiab txawm tias dej cawv yog qhov tshwm sim ntawm kev ua kom lub cev zom zaub mov. Tom qab cov khoom sib txawv no yog cov txheej txheem metabolic ntawm cov kab mob me me uas hloov cov khoom siv organic - tshwj xeeb tshaj yog carbohydrates - mus rau hauv cov tshuaj yooj yim, nrog rau kev tso tawm lub zog. Tsab xov xwm no tham txog kev txhais ntawm kev ua kom lub cev zom zaub mov, cov theem ntawm cov txheej txheem, hom kev ua kom lub cev zom zaub mov, cov kab mob me me uas koom nrog, thiab cov yam ntxwv uas cuam tshuam rau kev ua kom lub cev zom zaub mov zoo.
Nkag Siab Txog Kev Ua Kom Qhuav
Feem ntau, kev ua kom cov khoom noj muaj zog (xws li qabzib) yog cov txheej txheem ntawm kev rhuav cov organic sib xyaw (piv txwv li, qabzib) mus rau hauv cov sib xyaw yooj yim dua nrog kev pab los ntawm cov kab mob me me lossis cov enzymes uas lawv tsim tawm. Hauv cov ntsiab lus ntawm microbiology, kev ua kom cov khoom noj muaj zog feem ntau tshwm sim thaum tsis muaj oxygen (anaerobic) lossis nyob rau hauv cov xwm txheej ntawm cov pa oxygen tsawg heev. Lub hom phiaj tseem ceeb ntawm kev ua kom cov khoom noj muaj zog yog los tsim lub zog hauv daim ntawv ntawm ATP (adenosine triphosphate) kom lawv thiaj li muaj sia nyob, loj hlob, thiab rov tsim dua.
Tsis zoo li kev ua pa aerobic, uas tsim tau lub zog ntau dua, kev ua kom lub cev tsis muaj zog. Txawm li cas los xij, kev ua kom lub cev tsis muaj zog yog ib txoj hauv kev tseem ceeb rau cov kab mob me me hauv cov chaw uas tsis muaj oxygen, xws li hauv cov khob cij, mis nyuj khaws cia, lossis cov nroj tsuag uas kaw.
Cov Ntsiab Lus ntawm Kev Ua Kom Fermentation Metabolism
Yuav kom nkag siab txog kev ua kom cov kab mob me me (microorganisms), nws yog ib qho tseem ceeb kom nkag siab txog seb cov hlwb ua zog li cas. Hauv luv luv, kev ua kom cov hlwb ua zog pib nrog glycolysis, qhov kev rhuav tshem cov piam thaj (glucose) ua ob lub pyruvate molecule. Glycolysis tsim ib qho me me ntawm ATP thiab tus neeg nqa hluav taws xob NADH. Nyob rau hauv cov xwm txheej aerobic, NADH raug reoxidized los ntawm cov saw hlau thauj hluav taws xob, nrog rau oxygen ua tus txais hluav taws xob kawg. Txawm li cas los xij, hauv kev ua kom cov hlwb ua zog, oxygen tsis muaj, yog li cov hlwb yuav tsum nrhiav lwm txoj hauv kev los "rov ua dua" NADH rau hauv NAD⁺ kom txuas ntxiv glycolysis.
Qhov no yog qhov uas kev ua kom lub cev fermentation los ua si: pyruvate lossis nws cov derivatives yuav txais cov electrons los ntawm NADH, yog li rov tsim dua NAD⁺. Thaum muaj NAD⁺, glycolysis tuaj yeem txuas ntxiv mus thiab ATP raug tsim tawm, txawm tias muaj tsawg.
Cov Theem Dav Dav ntawm Cov Txheej Txheem Fermentation
Txawm hais tias hom kev fermentation sib txawv, feem ntau fermentation hauv microorganisms suav nrog cov theem hauv qab no:
1. Kev npaj cov khoom siv
Lub hauv paus chiv thawj feem ntau yog cov carbohydrates (glucose, sucrose, maltose, lactose), tab sis nws kuj tuaj yeem los ntawm cov hmoov txhuv nplej siab lossis cellulose, uas thawj zaug raug rhuav tshem los ntawm cov enzymes. Hauv kev tsim tempeh, piv txwv li, cov protein taum pauv thiab cov carbohydrates raug rhuav tshem los ntawm cov enzymes pwm. Hauv kev tsim daim kab xev, cov hmoov txhuv nplej siab hauv cassava lossis mov glutinous raug hloov mus ua cov suab thaj yooj yim los ntawm cov enzymes poov xab.
2. Glycolysis
Cov piam thaj (glucose) raug rhuav ua pyruvate hauv lub cytoplasm ntawm lub cell. Theem no tsim tau lub zog ntawm 2 ATP rau ib lub molecule qabzib thiab NADH.
3. Kev txo qis ntawm pyruvate (lossis nws cov derivatives)
Tom qab ntawd pyruvate raug hloov mus ua cov khoom kawg ntawm kev fermentation, xws li lactic acid lossis ethanol. Thaum lub sijhawm no, NADH tso nws cov electrons, hloov rov qab mus rau NAD⁺.
4. Kev tsim khoom thiab kev hloov pauv ib puag ncig
Feem ntau cov khoom siv fermentation hloov cov saj, aroma, texture, thiab lub sijhawm khaws cia ntawm cov khoom noj. Cov kua qaub ua rau pH qis dua, tiv thaiv kev loj hlob ntawm cov kab mob uas lwj, thaum cawv thiab carbon dioxide pab ua rau muaj cov yam ntxwv tshwj xeeb ntawm cov mov ci thiab dej haus fermented.
Hom Kev Ua Kom Qhuav thiab Piv Txwv
1. Kev Ua Kua Lactic Acid
Kev ua kom cov kua qaub lactic tshwm sim thaum cov pyruvate raug txo kom ua cov kua qaub lactic. Cov txheej txheem no feem ntau tshwm sim rau cov kab mob lactic acid xws li Lactobacillus, Streptococcus, thiab Leuconostoc. Qhov tshwm sim yog qhov ua rau muaj kua qaub ntau ntxiv.
Piv txwv ntawm daim ntawv thov:
– Mis nyuj qaub (feem ntau muaj Lactobacillus bulgaricus thiab Streptococcus thermophilus)
– Kimchi thiab sauerkraut (zaub uas tau fermented los ntawm cov kab mob lactic acid)
- Kev pickling thiab fermentation ntawm qee cov ntses
- Hauv tib neeg lub cev, lactic acid fermentation kuj tshwm sim hauv cov leeg thaum tsis muaj oxygen.
Kev ua kom cov kua qaub lactic fermentation muaj peev xwm muab faib ua:
- Homofermentative, tsim cov lactic acid feem ntau.
– Heterofermentative, tsim cov lactic acid nrog rau CO₂ thiab lwm yam tshuaj xws li ethanol lossis acetic acid.
2. Kev Ua Cawv Fermentation
Feem ntau cov poov xab xws li Saccharomyces cerevisiae ua cov cawv fermentation. Hauv cov txheej txheem no, pyruvate hloov mus ua acetaldehyde thaum tso CO₂, tom qab ntawd acetaldehyde raug txo kom ua ethanol.
Piv txwv ntawm daim ntawv thov:
– Mov ci: CO₂ ua rau cov hmoov nplej nce, thaum ethanol feem ntau ua pa thaum ci.
– Cawv, cawv txiv hmab thiab cawv ib txwm muaj: ethanol yog cov khoom tseem ceeb uas xav tau.
– Daim kab xev: tsim cov ethanol thiab ntau yam tsw qab sib txawv los ntawm kev sib xyaw ua ke ntawm cov poov xab thiab cov kab mob me me.
3. Kev Ua Kua Acetic Acid
Qhov kev ua kom cov kua qaub no muaj feem cuam tshuam nrog kev tsim cov kua qaub acetic (vinegar). Hauv kev siv tshuab, cov kab mob acetic acid xws li Acetobacter aceti hloov ethanol mus ua acetic acid, ib qho txheej txheem uas xav tau oxygen (aerobic). Yog li ntawd, nws feem ntau raug cais ua "fermentation" hauv kev lag luam zaub mov, txawm hais tias nws txawv ntawm kev ua kom cov kua qaub anaerobic ntshiab.
Piv txwv ntawm daim ntawv thov:
- Kua txiv apple cider vinegar, kua txiv mov, thiab ntau hom kua txiv hmab.
4. Kev Ua Kom Butyrate Thiab Lwm Yam
Qee cov kab mob me me, xws li Clostridium, tuaj yeem tsim cov kua qaub butyric, acetic acid, butanol, acetone, thiab roj. Cov txheej txheem no tseem ceeb rau cov kab mob me me thiab kuj tseem tuaj yeem ua rau qee yam khoom noj puas tsuaj thaum tsis xav tau.
Cov kab mob me me uas ua lub luag haujlwm hauv kev ua kom fermentation
Fermentation muaj ntau pawg ntawm cov kab mob me me, suav nrog:
- Cov kab mob lactic acid: Lactobacillus, Lactococcus, Streptococcus, Pediococcus.
– Cov poov xab: Saccharomyces, Candida (hauv qee qhov kev fermentations ib txwm muaj).
– Pwm: Rhizopus oligosporus hauv tempeh, Aspergillus oryzae hauv kua ntses thiab miso. Pwm feem ntau ua lub luag haujlwm hauv kev rhuav tshem cov molecules nyuaj los ntawm cov enzymes, yog li ua rau muaj kev fermentation ntxiv los ntawm cov kab mob lossis cov poov xab.
Hauv ntau yam khoom ib txwm muaj, kev ua kom siav tsis yog ua los ntawm ib hom kab mob me me xwb, tab sis yog los ntawm ib pawg kab mob me me. Lawv txoj kev sib cuam tshuam ua rau muaj cov saj thiab cov yam ntxwv sib txawv. Piv txwv li, hauv cov qos yaj ywm uas tau ua kom siav (kab xev), pwm thiab poov xab ua rau cov hmoov txhuv nplej siab tawg thiab tsim cawv, thaum qee cov kab mob tuaj yeem tsim cov kua qaub uas ua rau cov saj sib npaug.
Cov Yam Cuam Tshuam Rau Kev Ua Kom Fermentation Zoo
Kev ua kom fermentation zoo nyob ntawm seb muaj tej yam xwm txheej ib puag ncig thiab kev tswj cov txheej txheem li cas. Cov yam tseem ceeb suav nrog:
1. Kub
Txhua yam kab mob me me muaj qhov kub zoo tshaj plaws. Piv txwv li, mis nyuj qaub feem ntau yuav yaj thaum sov, thaum cov zaub yuav yaj thaum sov. Yog kub dhau ces yuav tua tau cov kab mob me me, thiab yog kub dhau ces yuav ua rau cov txheej txheem no qeeb.
2. pH (qaug zog)
pH cuam tshuam rau kev ua haujlwm ntawm enzyme thiab kev loj hlob Cov kab mob me me. Cov kab mob lactic acid feem ntau ua rau pH qis dua, yog li pab khaws cov khoom.
3. Muaj pa oxygen
Feem ntau, kev ua kom cawv thiab lactic acid fermentation xav tau cov xwm txheej anaerobic lossis cov pa oxygen tsawg. Ntawm qhov tod tes, kev tsim cov acetic acid xav tau oxygen.
4. Kev sib xyaw ntawm ntsev thiab qab zib
Ntshav tuaj yeem tiv thaiv cov kab mob uas ua rau lwj thiab xaiv qee cov kab mob (piv txwv li, hauv kev ua zaub mov). Qab zib yog ib qho tseem ceeb hauv ntau yam kev ua kom lwj, tab sis qhov concentration siab dhau tuaj yeem rub dej los ntawm cov hlwb microbial, thiab tiv thaiv kev loj hlob.
5. Kev huv thiab kev ua qias tuaj
Kev kis kab mob los ntawm cov kab mob tsis xav tau tuaj yeem ua rau puas qhov saj, txo qhov zoo, lossis txawm tias tsim cov tshuaj lom. Yog li ntawd, kev tu cev huv si thiab kev siv cov kab mob pib yog qhov tseem ceeb hauv kev lag luam.
6. Lub sijhawm ua kom siav
Kev fermentation luv dhau tuaj yeem ua rau cov khoom "tsis tiav", thaum ntev dhau tuaj yeem ua rau saj qaub dhau, cawv dhau, lossis cov qauv puas tsuaj.
Cov txiaj ntsig ntawm kev ua kom fermentation rau tib neeg
Ntxiv rau kev tsim cov khoom uas muaj saj thiab aroma sib txawv, fermentation kuj muab ntau yam txiaj ntsig:
- Ua kom lub sijhawm khaws cia ntev dua los ntawm kev txo qis pH, tsim cov cawv, lossis cov tshuaj tua kab mob.
- Ua kom muaj txiaj ntsig zoo rau kev noj haus, piv txwv li ua kom muaj qee cov vitamins thiab rhuav tshem cov tshuaj antioxidants.
- Txhim kho kev zom zaub mov, tshwj xeeb tshaj yog cov khoom uas muaj probiotics xws li yogurt.
- Tsim cov qauv tshiab thiab cov saj tshiab uas ua tsis tau los ntawm kev ua noj ib leeg xwb.
Kev kaw
Cov txheej txheem fermentation hauv cov kab mob me me yog ib txoj kev ua kom lub cev zom zaub mov uas tso cai rau cov hlwb kom tau txais lub zog hauv qab cov xwm txheej uas muaj oxygen tsawg thaum tsim cov khoom siv tshuaj uas hloov cov yam ntxwv ntawm cov khoom noj. Los ntawm glycolysis thiab cov tshuaj tiv thaiv tom qab ntawd los rov ua dua NAD⁺, cov kab mob me me muaj peev xwm ciaj sia thiab vam meej. Rau tib neeg, fermentation yog ib qho thev naus laus zis muaj txiaj ntsig zoo, ob qho tib si rau kev tsim khoom noj, kev khaws cia, thiab kev txhim kho cov khoom noj ua haujlwm. Kev nkag siab txog cov hom fermentation, cov kab mob me me uas koom nrog, thiab cov yam ntxwv uas cuam tshuam rau cov txheej txheem yuav pab tsim cov khoom fermented muaj kev nyab xeeb, zoo, thiab sib xws.
