Tiu lun mn cng ngh sinh hc thc phm GVHD: TS m Sao Mai

Tiu lun mn cng ngh sinh hc thc phm GVHD: TS m Sao Mai

VIN CNG NGH SINH HC V THC PHM

(( - (( Tiu lun mn: Cng Ngh Sinh Hc Thc Phm ti: Cng Ngh Sinh Hc Trong Sn Xut Nm Men S Dng Trong Sn Xut Ru Vang GVHD:TS m Sao MaiLp DHTP4

Danh sch nhm: 91.Nguyn Thanh Hi 081023112.Nguyn c Vinh 08106921

3.Phm Xun Quang 081070514.K Nht Trung 08106851

5.Nguyn Vn Phng 08107671

TPHCM, Thng 1/2011MC LC

3I. S LC V NM MEN V NG DNG TRONG CNG NGH THC PHM.

31.1 S lc v Nm Men:

31.1.1. Hnh dng v kch thc

31.1.2. Cu to t bo nm men

41.1.3.S sinh sn ca nm men

41.1.4. Phn loi nm men

51.1.5. Cc qu trnh sinh l ca t bo nm men:

91.1.6. Cc hnh thc h hp ca nm men

91.2. ng dung cua nm men trong cng ngh thc phm:

9II. NM MEN TRONG SN XUT RU VANG.

92.1Khi qut ru vang

92.1.1. Lch s ru vang

112.1.2.Phn loi ru vang:

142.1.3 Cc thnh phn chnh ca ru vang:

152.1.4.Tc dng ca ru vang.

172.2. Cc loi nm men trong sn xut ru vang:

172.2.1. Nm mem ru vang t nhin :

172.2.2. Nm men ru vang nui cy thun chng.

202.3 Cc chng nm men gy h hng ru vang:

222.4. H Vi Sinh Vt Trong Ln Men Ru Vang T Nhin

222.5. Dinh Dng Nm Men V Cht Lng Ru Vang

242.6 Sn xut vang

252.6.1 Men ging trong sn xut vang.

262.6.2 Qu trnh ln men.

26a. Cc iu kin ca qu trnh ln men:

27b. Cc giai on ca qu trnh ln men :

282.7. Cac nhn t anh hng n qua trinh ln men vang:

282.7.1. Anh hng cua oxy:

292.7.2. Anh hng cua nhit :

292.7.3. nh hng ca ng:

292.7.4. nh hng ca pH mi trng.

292.7.5. Anh hng cua anh sang.

302.7.6. Anh hng cua nng ru.

302.7.7. Anh hng cua ngun nit.

302.7.8. Anh hng cua mt t bao nm men.

302.7.9. Anh hng cua cht sat trung.

312.7.10. Anh hng cua ham lng CO2.

32III. KT LUN V KIN NGH.

33TI LIU THAM KHO

I. S LC V NM MEN V NG DNG TRONG CNG NGH THC PHM.1.1 S lc v Nm Men:

Nm men l tn chung ch nhm nm men c cu to v sinh sn bng cch ny chi v phn ct. Chng phn b rng ri khp ni. c bit chng c mt nhiu t trng nho v cc ni trng hoa qu. Ngoi ra thy chng c mt trn tri cy chn, trong nhy hoa, trong khng kh v c ni sn xut ru vang.

1.1.1. Hnh dng v kch thc ( Hnh dng t bo nm men:

Nm men thng c hnh dng khc nhau, thng c hnh cu, hnh elip, hnh trng, hnh bu dc v c hnh di. Mt s loi nm men c t bo hnh di ni vi nhau thnh nhng dng si gi l khun ty (Mycelium) hay khun ty gi (Pseudo mycelium). Tuy nhin hnh dng ca chng khng n nh, ph thuc vo tui ca nm men v iu kin nui cy.

( Kch thc t bo nm men

T bo nm men thng c kch thc rt ln gp t 5 10 ln t bo vi khun.

Kch thc trung bnh:

- Chiu di: 9 10 m

- Chiu rng: 2 7 m

Kch thc cng thay i, khng ng u cc loi khc nhau, cc la tui khc nhau v iu kin nui cy khc nhau.

1.1.2. Cu to t bo nm men T bo nm men cng nh nhiu loi t bo khc c cu to ch yu t cc phn c bn nh sau:

- Thnh t bo: cu to t nhiu thnh phn khc nhau. Trong ch yu l:

glucan, manan, protein, lipid v mt s thnh phn nh khc nh kitin, volutin,

- Mng nguyn sinh cht: gm cc hp cht phc tp nh protein, phospholipit

enzyme permeaza

- Cht nguyn sinh: thnh phn cu to ch yu l nc, protit, gluxit, lipit v cc mui khong, enzyme v c cc c quan trong .

- Nhn t bo

- Nhng thnh phn c quan con khc: khng bo, ty lp th, riboxom,

1.1.3.S sinh sn ca nm men Nm men c mt s hnh thc sinh sn sau:

- Sinh sn bng cch ny chi.

- Sinh sn bng cch phn i.

- Sinh sn bng bo t v s hnh thnh bo t.

+ Tip hp ng giao

+ Tip hp d giao

+ Sinh sn n tnh

1.1.4. Phn loi nm men Ch yu c hai lp: nm men tht (Ascomyces) v lp nm men gi (Fungi

imporfecti)

- Lp nm men tht (lp Ascomyces lp nm ti):

+ Phn ln nm men dng trong cng nghip thuc lp Ascomyces, a s thuc

ging Saccharomyces.

+ Ging Endomyces

+ Ging Schizosaccharomyces

- Lp nm men gi (Fungi imporfecti nm men bt ton):

+ Crytococus (toscula, tornlopsis)

+ Mycoderma

+ Eandida

+ Geotrichum ( c xp vo lp nm mc)

+ Rhodotorula

1.1.5. Cc qu trnh sinh l ca t bo nm men:* Sinh dng ca nm men

Cu to ca t bo nm men thay i khc nhau ty theo loi, tui v mi trng sng, nhng nhn chung bao gm:

- Nc: 75 85%

- Cht kh: 15 25% . Trong cht khong chim 2 14% hm lng cht kh.

Nm men cng nh cc sinh vt sng khc cn oxy, hydro, cacbon, nit, phospho, kali, magi,

- Dinh dng Cacbon

Ngun Cacbon cung cp l cc loi ng khc nhau: saccarose, maltose, lactose, glucose

H hp hiu kh:

C6H12O6 + 6 O2 ( 6CO2 + 6H2O + 674 cal

H hp k kh

C6H12O6 ( 2CH3CH2OH + 2 CO2 + 33 cal

- Dinh dng oxy, hydro: c cung cp cho t bo t nc ca mi trng nui cy hay dch.

- Dinh dng Nit:

Nm men khng c men ngoi bo phn gii protid, nn khng th phn ct albumin ca mi trng m phi cung cp nit dng ha tan, c th l m hu c hoc v c. Dng hu c thng dng l acid amin, pepton, amid, ur. m v c l cc mui amon kh nitrat, sulfat

- Cc vitamin v cht khong:

Cht khong c nh hng to ln n hot ng sng ca nm men:

+ Phospho: c trong thnh phn nucleoprotein, polyphosphat ca nhiu enzyme ca

sn phm trung gian ca qu trnh ln men ru, chng to ra lin kt c nng lng ln.

+ Lu hunh: tham gia vo thnh phn mt s acid amin, albumin, vitamin v enzyme.

+ Magi: tham gia vo nhiu phn ng trung gian ca s ln men.

+ St: tham gia vo cc thnh phn enzyme, s h hp v cc qu trnh khc.

+ Kali: cha nhiu trong nm men, n thc y s pht trin ca nm men, tham gia vo s ln men ru, to iu kin phc hi phosphorin ha ca acid pyruvic.

+ Mangan: ng vai tr tng t nh magi.

* C ch vn chuyn cc cht dinh dng vo trong t bo nm men

Nm men hon ton khng c c quan dinh dng ring bit, cc cht dinh dng m n s dng ch yu c vn chuyn qua thnh t bo theo hai con ng c bn:

- Thm thu b ng: trn thnh t bo nm men c nhng l nh, nhng l ny c

tc dng lm cho cht dinh dng vn chuyn vo trong t bo t mi trng bn ngoi nh p sut thm thu, ngc li cht thi trong qu trnh trao i cng c thi ra theo con ng ny.

- Hp thu ch ng: cc thnh phn dinh dng khng c kh nng xm nhp vo t bo theo con ng th nht th lp tc c h permeaza hot ha. Permeaza l mt protid hot ng, chng lin kt vi cht dinh dng to thnh hp cht v hp cht ny chui qua thnh t bo trong, ti y chng li tch ra v permeaza li tip tc vn chuyn tip.

* Qu trnh sinh trng v pht trin

- S sinh trng

Trong qu trnh nui cy, trong iu kin dinh dng y , t bo nm men tng nhanh v kch thc v ng thi sinh khi c tch ly nhiu.

- S pht trin

Cc nm men sinh sn bng phng php nhn i thng cho lng sinh khi rt ln sau mt thi gian ngn. Trong trng hp sinh sn theo phng php ny th trong dch nui cy s khng c t bo gi. V rng t bo c phn chia thnh hai c nh vy t bo lc no cng trng thi ang pht trin. T bo ch gi khi mi trng thiu cht dinh dng v t bo khng c kh nng sinh sn na.

Tuy nhin a s nm men sinh sn bng phng php ny chi nn hin tng pht hin t bo gi rt r. Khi chi non tch khi t bo m sng c lp th ni tch trn t bo m to thnh mt vt so. Vt so ny s khng c kh nng to ra chi mi. C nh vy t bo m s chuyn thnh t bo gi theo thi gian.

xc nh s lng t bo nm men pht trin theo thi gian hin nay ngi ta dng nhiu phng php khc nhau nh:

+ Xc nh s lng t bo bng phng php m trc tip trn knh hin vi hay gin tip trn mt thch.

+ o c ca t bo trong dung dch nui cy trn c s xy dng mt th

chun ca mt t bo

Qu trnh sinh trng ca nm men trong dch ln men tnh c th chia lm 5 giai on:

H1.1.Qu trnh sinh trng v pht trin ca nm men

Giai on tim pht: giai on ny t bo lm quen vi mi trng, sinh khi cha tng nhiu.

Giai on logarit: y l giai on pht trin rt nhanh, sinh khi tng o t, km theo s thay i mnh m ca dch ln men.

Giai on chm dn: tc sinh trng nm men gim dn, thnh phn dch ln men cn li t, cc sn phm ln men c tch t nhiu.

Giai on n nh: s lng t bo nm men khng tng na, tc sinh sn bng tc cht.

Giai on cht: tc cht tng nhanh, tc sinh sn rt t do s lng t bo nm men gim dn.

1.1.6. Cc hnh thc h hp ca nm men nm men h hp l qu trnh h hp kh phc tp, n xy ra theo hai chiu hng khc nhau. V th ngi ta phn thnh 2 loi h hp : h hp hiu kh v h hp ym kh.1.2. ng dung cua nm men trong cng ngh thc phm:

- nm men c vai tr rt to ln trong s pht trin ca nghnh cng ngh sinh hc ni chung v cng ngh thc phm ni ring. T lc con ngi bt u ng dng nm men trong sn xut thc phm, c rt nhiu cc thc phm c gi tr ra i p ng nhu cu tiu dng thc phm phong ph v a dng ca i sng. nm men c ng dng trong cng nghip nc gii kht, trong sn xut bnh m, trong sn xut ru bia. Ch tnh ring cng nghip nc gii kht c hng trm ngn sn phm ln men t nc qu, t thc vt vi hng trm cch ln men vi nhng liu lng nm men v nhng chng loi nm men khc nhau.

II. NM MEN TRONG SN XUT RU VANG.

2.1Khi qut ru vang

2.1.1. Lch s ru vangnh hng ca khoa hc v x hi c tc ng ln lch s ru vang. Chng ng ca ru vang k tha s pht trin ca k thut trng nho v k thut sn xut. Ngoi ra n cn pht trin da trn s m rng ca ngnh thng mi ru, thm vo l s nh hng nh t phong tc, th nhng

Hnh nh thn ru vang Dinoysustrong Thn thoi Hy Lp trn mt chic bnh cNgun gc ban u t Trung ng

Truyn thuyt Ba T k rng mt cng cha trong cung in khm ph ra ru vang. V cng cha ny khng c vua cha yu mn nn c t vn bng cch n nhng qu nho b thi ra. Nng b say, chong v ng thip i. Khi thc gic, cng cha thy khng cn cng thng, thay i cch c x v li c s yu mn ca vua cha. Sau nh vua loan truyn khm ph ny ca cng cha ra khp cung in v ra lnh ra tng sn xut ra nhng qu nho hng kia.Nh vy ru vang c hnh thnh l do s ln men ca cc qu nho v c pht hin mt cch tnh c. Vic trng nho v ung ru vang bt ngun t khong 4000 nm trc cng nguyn. Nhng pht hin ny bt ngun t vng bin Caspian v Lng H, ngy nay l Iran. Nhng ngi Ai Cp nhn ra s khc nhau trong cht lng ru vang. Cc nh kho c khai qut c mt s ni cha nhng h ru vang chm di t, ngi xa pht hin ra vic ct tr ru trong hm vi nhit khc nhau c nh hng n cht lng ru.

Bt ngun vi s ng gp ca Hy Lp La M

Ru vang n vi chu u cng vi s pht trin ca vn minh Hy Lp t khong nm 1600 trc cng nguyn. Trong thin anh hng ca Iliad v Odyssey ca Homer cng c nhng on m t c sc v ru vang. Ngi La M c nhng ng gp quan trng trong vic la chn ra cc loi nho v mu nho, c im ca cc loi nho khi chn, nhn bit c bnh ca nho, cc loi t thch hp trng. H tr nn thng tho hn trong vic ct ta chm sc, tng nng sut v cht lng.

2.1.2.Phn loi ru vang:Theo truyn thng, ru vang c nh ngha l sn phm ln men t dch nc nho c cha cn khng qua chng ct. Tuy nhin, gn y ngi ta m rng khi nim ny ch cc loi ru ln men t cc loi qu khc nh to, du, da, l, o.. Hin nay, ty thuc vo mc ch ca nh sn xut m dch qu c th l i tng ca nhiu qu trnh ln men khc nhau.

Ln men ru: y l giai on quan trng nht trong qu trnh sn xut ru vang, cho php bin i cc loi ng trong dch nc qu thnh cn, kh CO2, v rt nhiu sn phm ru khc gp phn to ra hng v c trng ca vang.

Ln men malolactic: cho ti nay qu trnh ny c nghin cu mt cch rt h thng. N thc hin qu trnh chun ha di-axit malic thnh monoaxit, lm h pH ca mi trng. D(iu ny cho php thu c ru vang c v chua du hn. Ln men malolactic c p dng rt ph bin trong qu trnh sn xut cc loi ru vang cu Php nh Bordeaux hay cc loi ru champagne.

Ln men ru ln th hai trn c s ru vang ln men c b sung thm ng sacaroza ca ma hoc c ci: hay cn gi l qu trnh to bt, ng vai tr rt quan trng sn xut cc loi vang n. Qu trnh ny c thc hin di iu kin p sut cao hoc l trong thng g si, hoc trong chai ( phng php sn xut ru champagne )

Qua , chng ta c th chia ru vang thnh nhiu loi khc nhau ph thuc vo hm lng cn, ng st v hm lng CO2. Bn cnh , ru vang cng c th c phn loi theo mu sc nh vang , vang trng, vang hng Trong mi nhm li chia thnh nhiu loi nh khc nhau ty thuc vo hng, v c trng ca chng. iu ny c trnh by c th trong bng 1.1

Bng 1.1 Phn loi ru vangTrn th gii c Trn th gii c ti hng trm loi ru vang khc nhau. Mi loi c c trng bi mt phng thc ring, ty theo c im ca ru v tnh cht ca cng ngh. Trong phng thc c hai cch ch bin ru vang ph bin nht. l cch ch bin ru vang trng v ru vang .

Ru vang :

Khi ln men nc qu nho c ln vi xc qu ring gi l vang . Trong v qu c nhiu cht mu, cht tannin, cht gy mi thm nhng cht ny khi b phn hy lm tng lng cht ha tan c trong ru v to hng v phong ph cho ru, to mu sc p cho ru. khi ln men cng vi xc qu, ko theo c qun th men bm trn v qu. Trong v qu giu thc n v m, v khong nn qu trnh ln men dng hn. Ln men c xc qu thng c tin hnh nhit cao hn trch ly c cc cht mu, cht thm v tannin c th ha tan trong ru.

Kt thc ln men, cn tin hnh tch xc qu ra ru. Trong sn xut ln trc ht ngi ta cho ru chy qua mt tm li gi cc tp cht li. Ru ny c cht lng cao nht v c gi l ru vang git, vang chy. khi ru ngng chy th a vo my p. Ru vang p chim khong 15% tng s ru ch c, c th em trn vi vang chy ch bin. B c th em p ln na hoc qua x l, sy kh lm thc n cho gia sc.

Ru vang do ln men c xc qu nn cha nhiu tannin hn ru vang trng, c v cht hn. Do cn ln men malomalic chuyn ha axit malic sang axit lactic to cho ru v chua du cn i vi v cht ca tannin. ln men malomalic tt khng nn tit trng ru tr v ln men malomalic xy ra sau vi ngy, hoc vi tun sau ln men, vi khun Lactic hoc mt lng nh nm men Schizosaccharomyces c kh nng ln men malolactic nhanh v trit .

Ru vang trng:

Khc vi ru vang , ru vang trng c ln men t nc qu c tch b qu. V nc qu thng khng c mu nn c gi l vang trng. Hng v ca ru vang trng ch yu l do nc qu. Ru vang trng thng c ln men nhit thp hn ru vang gi hng cho ru. Ru vang trng thng c t v cht, c chua cao hn, cn cao hn vang .

Ni chung hin nay ngi ta dng phng php cy men thun chng vo dch ln men. Trc khi ln men cn tin hnh nhn ging t hai, ba n nhiu cp trn mi trng tng t nh dch ln men nhng c nng ng thp hn v b sung cht dinh dng, cung cp oxy. Men ging sau khi nhn c cy vo dch ln men vi t l 4-10% th tch.

Ln men ru vang trng tin hnh nhit thp hn so vi ru vang , khong 15-200C. Ru vang trng rt cn gi hng nn nhit thp s tt hn. Thi gian ln men l t 6-7 ngy hoc lu hn ty theo nhit v yu cu cng ngh.

Kt thc qu trnh ln men khi nhn thy ru khng cn si bt ln na, cn v xc men ng xung y thng. Khi c tin hnh gn cn, thay thng. Ru tr c chuyn sang thng mi, tip tc lng cn ri a vo tang tr.

2.1.3 Cc thnh phn chnh ca ru vang:

Nh trnh by trn, ru vang l sn phm ln men t nc qu, do vy ngoi sn phm chnh nh etanol, CO2 cn c cc sn phm ph khc ca qu trnh ln men nh ru bc cao, glyxerin, aldehit, axit, cht thm .. v cc thnh phn khc ca dch qu, chng hn nh polyphenol, mono, di v polysacarit, axit bo, acit amin... Tt c nhng thnh phn ny u gp phn lm nn hng, v c trng ca vang.

Thnh phn ca ru vang

Hm lng cc cht bay hi tnh theog/l do cc chng nm men sinh ra2.1.4. Tc dng ca ru vang.

Ru vang khng ch vai tr lm nn cho ba tic hay lm cho mn n ngon hn, m cn c li cho sc khe. Ung ru vang gip cho qu trnh tiu ha, chng y hi, c bit rt tt cho nhng ngi nghin thuc l. Tuy vy, nn ung ru vang c ngun gc xut x r rng, tt nht l cc hng ru ni ting nh cc dng ru vang Php, , Chile, Australia,... Nn trnh xa cc loi vang lm th cng trong nc nh cc bn.

Bn vn c khuyn co: Ru khng tt cho sc kho. i vi ru vang, iu hon ton ngc li. Nhiu nghin cu khoa hc trn th gii chng minh, ru vang l loi thc ung hp dn v tt cho sc kho con ngi.

Nng cn trong ru vang ch vo khong 11-14%, thp hn khong 4-5 ln so vi ru mnh, c nng t 40-75. Ru vang, c bit l vang , mang li nhiu li ch cho sc kho nu bn ung iu , khong 100-200ml/ngy.

Trnh nguy c mc bnh v tim mch v cc chng t qu

Thc t chng minh, t l ngi Php mc bnh mch vnh v t qu ch bng 1/2 so vi ngi M, mc d ngi dn hai quc gia ny c ch v s thch n gn ging nhau. V sao?Mt nguyn nhn rt n gin nhng t ai n, l n gi Php c thi quen ung ru vang, nht l vang , iu trong ba n hn so vi ngi M.

Chng li mt s tc nhn gy lo ho

Vi thnh phn trong ru vang c kh nng chng li qu trnh lo ho ca t bo. c bit, cht chng oxy ho flavonoid trong vang cao gp 10-20 ln so vi rau qu.

Mt cht chng lo ho khc ng lu resveratrol. Cht ny c nhiu trong v qu nho, nht l nho chn v hp th nhiu nh nng mt tri. Ngoi ra, resveratrol cn c kh nng chng nhim khun.

Gim qu trnh x va ng mchNguyn nhn hnh thnh cc mng x va ng mch l do qu trnh oxy ho ca lipoprotein trong thnh ng mch.Ru vang s gip tng hm lng HDL cholesterol (mt loi cholesterol c li cho c th) v ngn chn LDL (cholesterol xu) t lc bt u hnh thnh. Nh vy, c th ngn chn c s tc nghn mch mu.

Liu php mi cha bnh phiTheo nghin cu khoa hc c tin hnh ti Anh v M, hp cht chng xy ho resveratrol trong ru vang c kh nng gip cha tr bnh phi tc nghn mn tnh.

Kch thch n ung v tiu ho tt

Ch cn nhm nhp 100ml ru vang trong ba n, bn s cm thy ngon ming hn.Ru vang c kh nng trung ho lng cht bo, gip bn khng b y bng v cm thy d chu hn sau khi n.

Nhng li ch khc ca ru vang.

S tng hp cc vitamin C, B1, B3, B5, B6, km, axit lipoic... trong vang c tc dng ngn bnh tiu ng. Ngoi ra, ung ru vang iu cn l mt cch gip bn gim nguy c b cc bnh nh: Ung th, Alzheimer, parkinson...

2.2. Cc loi nm men trong sn xut ru vang:2.2.1. Nm mem ru vang t nhin :

Khi phn loi nm men tm thy trong nc qu ln men t nhin, ngi ta thy c nhiu loi, nhng ph bin hn c l mt s loi nh Saccharomyces ellipsoideus c th cho ru cao, Kloeckera apiculata c kh nng ln men t 4 5 ru. Mt vi nm men sinh mng khc c tn Schizosaccharomyces pombe c kh nng phn gi axit malic thnh axit lactic v cn lm cho ru c v cht. Ngoi ra cn c cc loi khc nh Hancelnula, Pichia. To mng trng trn mt ru.

mt s ni ngi ta sn xut ru vang bng cch ln men t nhin dch qu ti cng vi xc qu. Lc nm mem tt c ch nm mem khng tt v thc hin qu trnh ln men.

Vit Nam, ln men t nhin ch c ng dng ti cc c s vang quy m gia nh vng nho Ninh Thun .

n nh cht lng vang , thay v qu trnh ln men ru vang din ra mt cch t nhin , ngi ta iu khin qu trnh ln men theo mun bng chng nm nem c tuyn chn cn thn.

2.2.2. Nm men ru vang nui cy thun chng.Nm men c th dng trong sn xut ru vang rt phong ph v a dng. Do khi sn xut cn tin hnh tuyn chn chng ph hp nhm t c hiu qu cao v cht lng ru tt. chn chng hon ton thch hp, ngi ta cy chng ln mi trng dch qu nh dng v nh gi cc ch tiu sau:

Ln men tt trong mi trng ng nng cao, cho cn cao

C th ln men kit ng Chu c cn cao, ln men tt trong nhng khong pH nht nh.

C kh nng kt lng tt, lm ru trong nhanh.

To cho ru hng v thm ngon, khng nhim mi l , khng to vng trn mt ru. Ln men t nhin thng c cn khng cao, nh hn 10% theo th tch v r d b

nhim. Tri li men nui cy thun khit c nhiu u im nh ln men nhanh,cho cn cao,hng v vang khanh khit hn, mu sc p, d lng v d tch cn men hn.Nm men thun chng dng trong sn xut ru vang thuc ging Saccharomyces Lp

Ascomycetes H SacchromyceteaeGing Saccharomyces c ti 18 loi trong ch c mt s loi hay dng sn xut ru vang nh:

Saccharomyces cerevisiaeNm men ny ph bin trong qu trnh ln men nc qu chim ti 80% trong tng s Saccharomyces c trong nc qu khi ln men. Kh nng kt lng ca n ph thuc vo tng ni: cc t bo dng bi hoc dng bng. Ngun dinh dng cacbon ca loi ny l ng, cn v acid hu c, nhng tc nhn sinh trng l acid pantotinic, biotin, mezoinozit, thiamin v piridoxin.

a s cc t bo ca loi ny hnh ovan c kch thc (3 8) x (5 12) m, sinh sn theo li ny chi v to thnh bo t. Saccharomyces cerevisiae sinh ra enzyme invectara c kh nng kh ng sacaroza thnh fructoza v glucoza, v vy trong ln men ta c th b sung loi ng ny vo dung dch qu. Nm men chu c cn t 18 20% v/v.

Hnh 2.1:: Saccharomyces cerevisiae giai on cui ln men Saccharomyces cerevisiae kt lng nhanh v lm trong dch ru. ni ca ging ny c c tnh ring v kh nng to cn, chu sunfit, tng hp cc cu t bay hi v cc sn phm th cp to ra cho vang c mi v c trng ring bit.Giai on cui cng ca qu trnh ln men cc t bo Saccharomyces cerevisiae thng b gi, khng tip tc chuyn ng thnh cn v b cht rt nhanh.

Saccharomyces uvarumMen ny c tch t nc nho, ru len men t nhin. V hnh thi n khng khc vi cc loi khc. Kh nng sinh bo t kh mnh trn mi trng thch malt. Cc ni ca loi ny c th ln men 12 130 cn trong dung dch nc nho. Mt vi ni c dng trong sn xut ru vang.

Saccharomyces chevalieriTheo Lodder l Saccharomyces chevalieri Guilliermond. Nm men ny c tch t nc nho ln men t nhin, t ru vang non c gy men nc da hoc nc c. Saccharomyces chevalieri thun chng ln men nc nho c th to 160 cn. N thng ln vi Saccharomyces cerevisiae.

Saccharomyces oviformicsc tch ra t nc nho t ln men, nhng loi nm men ny t hn so vi Sacch. vini. Ging thun chng pht trin tt trong nc nho v cc loi nc qu khc, c kh nng chu c ng cao, cn cao, ln men kit ng v to thnh ti 180 cn.

Cc yu t sinh trng ca loi ny ging nh Sacch. vini v c kh nng chu c cn cao. Dng cc ni thun chng ca ging ny ln men dch qu c hm lng ng cao.

C hnh dng ging nh Saccharomyces cerevisiae v c th to thnh 18% ru trong qu trnh ln men, ging ny to thnh mng trn dch qu.S. oviformis ln men c glucose, fructose, mantose, saccarose, maltose v 1/3 rafinose, khng ln men c lactose, pentose. iu khc nhau c bn ca S. oviformis vi S. vini l: S. oviformis khng ln men c galactose v men ni ln b mt dch ln men to thnh mng.

Hai ging sn xut ru vang ny (S. vini v S. oviformis) c nhiu ni c dng trong sn xut.

Hanseniaspora apiculate Kloeckera apiculataKloeckera apiculata: kch thc tng i nh, c hnh ovan elip hoc hnh qu chanh, t bo c mt u nh ngi ta thng gi l men hnh chy. Sinh sn bng ny chi, rt ph bin v qu v nhim vo nc qu chim n 90% tng s men khi bt u ln men. N c th ln men to thnh 6 70 cn, nhng to ra mt lot cc acid bay hi cng nh cc este ca chng lm cho dch c mi tp v n cn km hm cc loi nm men chnh trong ln men, K. apiculata nhy cm vi SO2.

Trong ngh lm ru vang ngi ta khng mong mun loi men ny pht trin, nu c th ch cn c trong giai on u to c 3 40 cn.

Hnh2.2: Kloeckeraapiculata

2.3 Cc chng nm men gy h hng ru vang: 2.3.1. Saccharomyces lugwigii.

Kch thc ca t bo ln nht ca loi nm men hnh thoi ny c th t ti 25 m v ny chi hai u. Chng c mt vi mt s lng rt nh trn v qu nho, thnh thong gp dch nc nho c slffit ha. N c th ln men dch ng to ra c 16,8%v/v cn v chu c hm lng SO2 khong 6000mg/l. Chng c kh nng to axeton rt mnh v c th sinh ra 200 mg/l axetandehit trong qu trnh ln men k kh. y l vi sinh vt gy h hng ru nguy him nht. Sau vi tun, chng to ra kt ta v lng xung y chai v kt ta ny rt kh b ph v lm cho CO2 khng th thot ra c. 2.3.2 Brettanomyces vini( B.intermedius, B.schanderlii):

T bo ko di c xu hng kt thnh chui. N c tm thy trn lp vn ca ru hng, ru hoa qu v ru vang c gas v trn thnh ca thng ru. B.vini chu c mi trng c cn ln ti 15%v/v nhng li khng c kh nng song st khi hm lng SO2 vt qu 176mg/l. Khi ln men trong mi trng hiu kh n to ra mt lng ln ru isobutylic, caproic, isovaloric v ethy axetat ( hm lng este v c bit trong iu kin hiu kh, ln hn 76mg/l). S pht trin ca cc chng nm men thuc loi ny lm cho ru vang c mi tng t nh acxetamit v c Ribereaau Gayon gi l mi chut. N l mt trong nhng chng nm men thng gy h hng ru cn c quan tm gii quyt.2.3.3 Zygosaccharomyces (S.bailii, S.acidofilus, S.elegans)

Chng nm men ny c phn lp t qu nho, nhng n c tm thy ch yu trn tng ca cc hm ru. Kh nng chu cn v SO2 cao lm cho chng nm men ny l nguyn nhn chnh gy ra qu trnh ln men li cc loi ru vang ngt. Cc chng nm men c hot tnh fructoza mnh nn c kh nng ln men fructoza mnh hn glucoza. Ribereau Gayon cho rng y chnh l mt s chng nm men gy h hng ru vang mc d chng khng sinh ra cc hp cht d bay hi khng mong mun.

2.3.4 Turulopsis stellata (T.bacillaris)

C th phn bit cc chng nm men ny trong mi trng lng nh s xut hin ca hiu chi mc xung quanh t bo m to thnh hnh sao v trn mi trng rn chng c dng hnh que ca n. i khi ngi ta c th tm thy chng trn v qu nho, c bit l nho chn ni chu s thng tr ca cc chng thuc loi Botrytis cinerea. 70% s chng thuc loi T.stellata c Domercq phn lp Gronde v chng cn c tm thy trong cc vn nho ca Italia. T.stellata v Hanseniaspra uvarum hay xut hin trong nhng ngy u tin ca qu trnh ln men t nhin v c kh nng to cn yu (trung bnh 10%v/v), thng bin mt cui qu trnh ln men do chng khng c kh nng chu cn cao. Loi nm men c kh nng chu nhit rt tt (30-350) v c kh nng ln men ng fructoza nhanh hn glucoza.2.3.5. Haseniapora uvarum v dng bt ton ca n l Kloecketa qpiculata:

Cc t bo thuc loi ny u rt nh v c hnh trn nh qu chanh v cng c nhn ra bng chi hai u. Loi ny chim 15% khu h vi sinh vt trn v qu nho. Cho d cc chng nm men ny chu trch nhim chnh cho qu trnh ln men t nhin dch nc nho p nhng do ch chu c cn thp t 3,7-6,4%v/v nn chng nhanh chng b thay th bi cc chng nm men khc trong qu trnh ln men. Chng to ra nhiu axit axetic, trung bnh l 1g/l v ethy axetat l 125-374mg/l cng nh l amyl axetat v glyxerol. Mt s tc gi cho rng n to hng qu trong ru vang, theo mt s khc th do to ra nhiu ethy axetat nn n gy ra mi kh chu cho vang. Cc c tnh khc nhau ca mt s chng nm men ru

2.4. H Vi Sinh Vt Trong Ln Men Ru Vang T Nhin

H vi sinh vt trong ln me ru vang t nhin tng i phc tp v khng ng nht trong cc giai on ca qu trnh ln men.

Trong nc nho ti c nhng nhm vi sinh vt khc nhau ri t mi trng xung quanh, ch yu v qu, thn, cung v thit b. Phn ln trong h ny l nm mc: botrytis, Penicillium, Aspergillus, Mucor, Rhizopus, Alternaria, Ucinula v Cladosporium chim (79 90%), nm men: ch yu l Kloeckera/Hanseniaspora, mt lng t Candida, Metchnikowia, Cryptococcus, Pichia, Kluyveromyces v mt lng nh Saccharomyces cerevisiae chim (9- 22%), s cn li chim t l thp l vi khun khng sinh bo t hoc c bo t, x khun v Microbacter.

C nm men v vi khun u c th ng vai tr tiu cc v tch cc trong sn xut.

Khi phn loi nm men tm thy trong nc qu ln men t nhin, ngi ta thy rt c nhiu loi. H nm men trong giai on u (mt vi ngy u) ln men nc nho l Kloeckera nm men c dng hnh chy, chim u th (70 80% trong tng s nm men) v hot ng tch t c 2 4 cn ri ngng hot ng v cht dn, sau nm men hnh elip v ovan (Saccharromyces ellipsoideus) nhanh chng pht trin gy len men mnh, lng ng tiu hao nhanh v tch t cn etylic. Khi cn tng i cao (8-12%) th nm men hnh elip S.ellipsoideus hay l S.vini ngng pht trin v hot ng. Khi y nm men Saccharromyces oviformis tip tc ln men cho n khi kt thc. Mt vi nm men sinh mng khc c tn Schizosaccharomyces pombe c kh nng phn gii axit malic thnh axit lactic v cn lm cho ru c v cht. Ngoi ra cn c cc loi khc nh Hancelnula, Pichia to mng trng trn mt ru.

2.5. Dinh Dng Nm Men V Cht Lng Ru Vang

Trong cc ngun dinh dng th ngun cacbon v nit c quan tm hng u

2.5.1. Ngun dinh dng cacbon

Ngun dinh dng i vi nm men gm c: ng v dn xut, cc loi ru, axit hu c, axit amin, pectin, hydratcacbon v v.v Song mi loi nm men c quan h ring bit vi tng loi ng.

a s cc loi men ru vang ln men c glucoza, fructoza, sacaroza v galactoza. Rafinoza c s dng mt phn. Cn lactoza, melibioza, pentoza, dextrin v tinh bt khng c ng ha.

Theo cng s dng glucoza v fructoza (n thi im m nm men ln men c 50% fructoza) ngi ta chia nm men lm 3 nhm:

1) Nhm thch glucoza ln men glucoza t 80 85%, phn ln l cc loi thuc ging Saccharomyces, cng nh ging Saccharomycodes v Brettanomyces.

2) Nhm thch fructoza trong giai on ny ch s dng c 5 10% glucoza (S.baili, S.rouxii, T.stella).

3) Nm men a thch c hai loi ng v n khi s dng c 50% th glucoza cng thy tiu ha c 40 60% fructoza (S.rosei, Pitria membranaefacien).

Cc axit hu c chim v tr quan trng trong trao i cht ca nm men: chng c th kch thch hoc c ch sinh trng, cng c th l ngun cacbon v nng lng duy nht trong hot ng sng ca nm men.

Trong mi trng vi cc axit hu c khc nhau lm ngun cacbon th cht CO2 l cht hot ng sinh hc lin keetsvowis cc hp cht trung gian vi men.

H hp hiu kh:

C6H12O6 + 6O2 6CO2 + 6H2O + 674 cal

H hp k kh

C6H12O6 2CH3CH2OH + 2CO2 + 33 cal2.5.2. Dinh dng nit.

Ngun dinh dng nit cn thit cho cc cu t ca t bo cha nit, nh axit amin, protein, cc nucleotit purin v pyrimidin v mt s vitamin. Phn ln nm men khng ng ha c nitrat. Nm men cng c th ng ha c ure v pepton. Nit amoniac (N NH3) c trong dch nho (t 25 100 mg/l) c nm men ng ha trong vi gi u phc v sinh sn.

Theo gi tr dinh dng ca axit amin ngi ta chia chng thnh:

- Cc axit amin c nm men ng ha d dng l izolxin, triptophan, arginin, valin, histidin, axit asparatic.

- Cc axit amin c ng ha km treonin, phenylalanin, tirozin, methionin, rerin, lizin, histidin, axit glutamic, lxin, v prolin hon ton khng c nm men ng ha.

Nhng ngun nit rt cn thit cho cu to t bo, sinh sn, sinh trng ca nm men.

Thc nghim cho thy, tha oxy cng nh tha CO2 s lm thay i ln v trao i cht nit.Trong ln men ru vang cn lu n trao i cht cacbon v nit. Cc cu t ny u c nh hng n cc tiu ch cm quan ca vang. Tha cc cht cha nit trong iu kin ln men oxy s cho vang nhng tng mi khng thch hp. khc phc hin tng ny ngi ta ch th ln men nhiu ln.2.5.3. Dinh dng oxy, hydro.

c cung cp cho t bo t nc ca mi trng nui cy hay dch.2.5.4. Dinh dng cc nguyn t v c.

Men ru vang cng cn cc nguyn t khong dinh dng nh phospho, lu hunh, kali, canxi v.v

Phospho: c trong thnh phn nhng hp cht quan trng nht ca t bo. Hp cht ng vai tr quan trng trong cc chuyn ha vt cht c bit l trong trao i cht cacbon v vn chuyn nng lng. Nm men s dng tt ngun phospho v c l ortophosphat.

Lu hunh: nhng hp cht ng vai tr quan trng trong hot ng sng ca nm men. Trong dch nho c ngun S t nhin l cc gc sulfat. Mt lng nh S cng lm tng lc ny chi ca nm men.

Canxi v kali cn thit cho s hot ng ca mt s enzym.

Cc nguyn t vi lng c nh hng n sinh trng v ln men.

2.5.5. Cc nhn t sinh trng.

y l cc cht kch thch sinh trng, gm c vitamin, cc axit amin, cc baz purin v pyrimidin.

Cc vitamin nhm B thuc nhm cht xc tc sinh hc c hot tnh sinh hc mnh hn c. Trong nm men c th c nhng loi tng hp c mt, hai, ba hoc mt vi cht trong cc vitamin ny.

Vitamin cng vi axit amin c trong mi trng c tc dng rt ln n sinh trng v trao i cht ca t bo nm men.

Vi c ddiemr nc qu giu dinh dng thch hp vi nhiu loi vi sinh vt nn nc qu d b ln men t nhin kh iu khin c, cng d b oxi ha lm sm mu. Mun hn ch, ngi ta cho thm SO2 cho nc qu sng. Vi nc qu sau khi p thng b sung thm ng, iu chnh pH bng amoni kali tactarat, b sung thm ngun nit. Dng Na2SO3 ngoi tc dng bo qun, n cn tc dng ln men to thnh glyxerin nhiu hn tng thm hng v c trng ca vang.

2.6 Sn xut vang

Ngy nay, nhiu nc trn th gii, sn xut ru vang vn gn lin vi kinh t nng tri, c ngha l cc gia nh trng nho thng c mt xng sn xut ru vang quy m nh ngay nng tri ca mnh, nhng ru c tn tr rt cn thn trong cc ng hm qua thi gian di, c khi hng trm nm.

Nho c thu hoch vo ma thu. Qu hi v c ra sch, p ly nc hoc nghin nh ri cho vo thng ln men s b cc thng h. nhiu xng vn dng thng g ln men. Dch qu c tip 2% ging nm men t dch ln men hoc cn men nhng m trc v cho ln men 20 22oC, khng nn qu 25 28oC. Thi gian ln men s b t 1 n 2 ngy hoc 3 n 4 ngy, sau p qua my thy lc hoc vt p. Nu ly ru vang c mu th khng qua lc p m c khi dch ln v nghin cho vo ln men. Nu l loi qu ht to kh p, ta c th em ngm ng. trng hp gi dch lm nguyn liu len men dn sau ny th dch qu p khng cho ln men s b m bo qun bng sulfit vi liu lng l 30 120 mg /l. trc khi ln men cn kh thnh ri dng kt ta .

Chun b dch ln men: cc loi nc qu thng c acid cao v ng thp hn so vi nc nho. Trc khi cho ln men cn iu chnh v pH 3.2 3.5 v b sung thm dch ng vo nc p qu. Trng hp l dch xiro (dch qu ngm ng) th pha gp 2 n 3 ln dch qu c khong 16 18% ng. c th trong qu trnh ln men cn b sung thm ng. nu chn c loi qu c hm lng ng cao, ph hp vi nhu cu ln men l tt nht, nh vy sn phm thu c gi gn nh nguyn vn cc cht chit t qu hoc nhng sn phm chuyn ha ca chng.

2.6.1 Men ging trong sn xut vang.

Trong sn xut ru vang quy m nng tri (ch yu u M ) hoc cc x nghip cng nghip ln, ngi ta thng dng cc ngun ging nh sau:

Ging ban u hay ging khi ng dng quy m nng tri thng c lu tr t cc m ln men truyn thng t nhiu nm. Qua sng lc v tuyn chn nhiu nng tri c ging ban u tng i thun khit ca mt hn hp chng saccharomyces vini v saccharomices oviformis. Hn hp ging ny c gi dng sa c hoc bnh kh, nhit lnh khong 0 - 2. Trc khi s dng lm ging khi ng cn phi hot ha. Loi ging ny thng c dng quy m trang tri, nhng nhng sn phm vang ni ting thng l khu vc ny lm ra.

Hot ha n gin nht l nui cy trong mi trng nc nho c nng ng 10% hoc mi trng nc dch qu vi dch ng malt. Nu thy men pht trin km nn thm vo dch nc qu mt hn hp sau: amoni sulfat 100 g/l; vitamin - 0.25 g/l; canxi pantotenat 0.25 g/l; biotin 0.002 g/l theo t l 0.2 ml hn hp cho vo mt lt dch qu. Cng c th dng cao nm men thay cho hn hp ny.

Nhn ging t ging thun chng.

Ging thun chng c gi cc ng thch nghing ( c th di lp du parafin) hoc cc ng ng kh. Ging men c cy chuyn vo mi trng lng l dch qu nh trn vi ln, ri nhn tng dn 1 : 10 c lng ging a vo sn xut.

Cng c th dng li ging sau thi gian ln men chnh. Cc t bo nm men lng xung y thng c ly ra v x l ( ging nh dng li ging men bia).

Ging thun chng thng c dng trong cc nh my ln quy m cng nghip, c bit l cc nc ng u. C th dng ging thun chng hn hp hai loi s. vini v oviformis.

Dng h nm men t nhin bm vo v qu khi thu hoch ln men. Qu thu hi v , gi sch s, khng ra, p ly dch v c bit vi nho tm , gi c xc qu v dch, a vo ln men. Trc khi ln men cn sulfit ha dch qu ln men di, nm mc v cc tp khun khc. Trong iu kin thch hp, ging men ru vang s pht trin vt tri v cho cc m ln men tt.

cc nc c truyn thng lm ru vang truyn thng t lu i h vi sinh vt ru vang rt phong ph, nht l cc men ru vang c th pht tn rt rng, bm vo b mt v qu, lu tr trong t, cng nh trn b mt dng c cha ng v thit b sn xut.

cn trng (nht l rui dm) cng vi gi lm pht tn nm men. Tuy vy, dng nm men t nhin ny ch c cc vng c truyn thng sn xut vang lu i mi c th lm ra sn phm cht lng cao. thc t cng cho hay, cc sn phm ru vang tuyt ho trn th gii li chnh khu vc ny. Nhng, vi ging nm men t nhin hay b tp chng ln men cho ru thp v c th cht lng sn phm khng t nh mun.

2.6.2 Qu trnh ln men.a. Cc iu kin ca qu trnh ln men:

Nng ng: thch hp nht l 20 28%, nu cao hn th nng lc ln men gim v ngc li nu thp s khng to c iu kin cho qu trnh ln men. Trn thc t, nng ng 30 35% th s ln men b nh ch.

Oxy: nm men l loi vi sinh vt h hp ty tin v ch trong iu kin ym kh n mi

tin hnh ln men ru, nu trong mi trng cha nhiu oxy n s oxy ho ng, CO2 v nc ng thi sinh sn rt mnh, do khi mun c ru cn to iu kin ym kh, cn mun sn xut sinh khi nm men th phi to iu kin hiu kh.

pH mi trng:Trong thc t ln men nhng dch qu chua thng c ru vang ngon. i vi dch qu thng c pH t 2,8 3,8. Khong pH ny nm men vn hot ng c. Vng pH ti thch ca nm men l 4 6. Trong sn xut ru vang ngi ta thng chun b mi trng nc qu c pH bng 3,0 3,5.

Nhit : Nm men bn vng trong nhit thp v rt nhy cm vi nhit cao. Nhit ti u 28 30oC, khong 50oC v di OoC th ln men b nh ch. Trong thc t ngi ta ln men nhit 4 28oC.

Nng ru v CO2 : c tc dng kim hm s sinh sn cng nh kh nng ln men ca nm men,c ch hot ng ca vi khun acetic v chng oxy ha. Tuy nhin vic s dng SO 2 nh th no cho hp l khng phi l iu n gin, nu qu t s khng s l c nh mong mun cn qu nhiu s nh hng dn sc khe ngi s dng v cn to nn hng v khng tt cho vang . a s nm men ch ln men c ti nng ru 12 14%, vic thot kh CO2 c tc dng tt n qu trnh ln men. S thot kh CO2 s lm cho mi trng ln men lun lun b khuy ng, ko di c trng thi l lng ca nm men do lm tng nhanh s ln men.

b. Cc giai on ca qu trnh ln men :

Qu trnh ln men ru vang tri qua 2 giai on:

(Qu trnh ln men chnh

- Qu trnh ln men ru vang nho c th tin hnh trong cc bn g si , btng ct thp hoc thng kim loi vi nhiu kch thc, hnh dng khc nhau. Thng thng, sau khi tip ging men thun vo bn ln men khong vi gi th xut hin nhng du hiu u tin ca qu trnh ln men l nhng bt kh CO2 xut hin bm xung quanh thnh bn ln men v t t hnh thnh nhng c o bi b mt nc nh ln dn ln v bao ph cc b mt.

- Qu trnh ny s mnh dn cc gi tip theo. Thng qua vic theo di bin ng ca nhit , lng CO2 thot ra, dy v mu sc ca lp bt v nht l tc gim dn ca hm lng ng ta s xc nh c thi im cc i ca qu trnh ln men vang. Sau qu trnh ln men vang s yu dn i n khi kt thc qu trnh ln men chnh. Mt chu trnh ln men chnh c th ko di t 5 18 ngy.Ty thuc vo tng loi ru vang c tin hnh bi nm men nh : Saccharomyces ellipsoideus , Saccharomyces cervisiae

Qu trnh ln men chnh l giai on to cn cho ru vang

( Qu trnh ln men ph:

Khi kt thc qu trnh ln men chnh s tip tc qu trnh ln men ph hay cn gi l ln men malolactic c thc hin bi vi khun lactic nhm to hng cho sn phm ru vang

thi k ln men ph, lng ng st tip tc chuyn ho thnh CO2 v C2H5OH d rt yu v chm chp. Qu trnh ln men ph ko di t 2 3 tun, c khi di hn ty thuc vo hm lng ng c trong dch nho v hot ca nm men thun mnh hay yu.

qu trnh ln men ph c tin hnh bi vi khun lactic nh : Lactobacillus , Pediococcus, Leuconostoc oenos. Trong qu trnh ln men ph cc acid hu c c trong qu cng nh c to ra trong giai on ln men ru s c chuyn ha tip tc nh acid malic s c chuyn ha thnh CO2 v acid lactic, lm cho v ca ru vang tr nn chua du v m. Cn acid citric v ng qu ( glucoseza , frutoseza ) c chuyn ha thnh dyaxetyl, axetoin, 2-3 butylenglicol l nhng cht tin thn trong vic to hng thm c trng cho vang ng thi qu trnh ny cn to ra axit acetic v axit lactic. Cc arginin c chuyn thnh ornitim.

Cui giai on ny, ru vang c hnh thnh, CO2 c bo ha , cc ht l lng trong vang, cc tanat v mui tartrat c lng xung lm cho vang tr nn trong.Vic ko di thi gian ln men ph ca vang nho khng phi bao gi cng cho kt qu tt hn, ngc li i khi lng ng st li l ngun thc n tt cho vi sinh vt gy hi. y chnh l nguyn nhn dn ti mt s bnh thng gp ru vang. Mt sn phm c coi l ln men hon ton kho mnh, nu hm lng cn st li t hn 1 2g /l

2.7. Cac nhn t anh hng n qua trinh ln men vang:

2.7.1. Anh hng cua oxy:

Hu ht cc chng nm men trong ln men ru vang thuc ging Saccharomyces. Chng l nhm vi sinh vt k kh ty tin. Khi trong mi trng lng oxy nm men phn hy ng dng lm ngun nng lng v cu to t bo tng sinh khi.

Trng hp thiu oxy (k kh) nm men s dng phn oxy ha tan trong mi trng sinh trng v ch yu l ln men.

Trong qu trnh ln men giai on u yu cu oxy cao nht nm men sinh sn, pht trin tng sinh khi. Nu c giai on nhn ging th cng cn phi cung cp oxy bng cch lc hoc sc kh.

2.7.2. Anh hng cua nhit :

Nhit ln men c nh hng n i sng ca nm men, n qu trnh ln men v cht lng ca sn phm.

Nhiu cng trnh nghin cu v sn xut ru vang xc nh c khong nhit ln men ru vang trng thch hp l 15 300C, nu ln men nhng thang thp hn th cng tt. Cn ln men ru vang (nc qu ln vi xc qu) phi chit xut cc cht thm v polyphenol t v qu nn cn thang cao hn, thng l 250C.

Nhit ln men cao, thi gian ca qu trnh ln men ngn, cn c th thp, ng st cn nhiu v hng v ca sn phm c khi khng tt.

2.7.3. nh hng ca ng:

Trong nc qu thng c hm lng ng khng u do vy ngi ta thng b sung thm ng saccharose. a s cc loi nm men hot ng bnh thng trong mi trng ng di 20%. C mt s chng hot ng mi trng c ng cao hn. Khi nhn ging thng dng mi trng c ng thp di 10%.

2.7.4. nh hng ca pH mi trng.

-Trong thc t ln men nhng dch qu chua thng c ru vang ngon. i vi dch qu thng c pH t 2,8 3,8. Khong pH ny nm men vn hot ng c. Vng pH ti thch ca nm men l 4 6.

-Trong sn xut ru vang ngi ta thng chun b mi trng nc qu c pH bng 3,0 3,5 ( Lng c Phm, 1998).

2.7.5. Anh hng cua anh sang.

Anh sang la yu t kim ham hoat ng cua nm men vang. c bit la cac tia cc tim se git cht t bao nm men, vi vy qua trinh ln men co n inh hay khng phu thuc vao thi tit cua tng thi vu.

2.7.6. Anh hng cua nng ru.

Qua trinh nui cy nm men chu yu la tao iu kin cho nm men phat trin sinh khi, at s lng mong mun. Song, nm men cung thc hin mt qua trinh ln men ru ang k (con phu thuc vao ch thng khng khi).

Thng trong dich nm men co khoang 4 - 6% ru. Nng ru sinh ra co anh hng n tc va kha nng phat trin cua nm men. Nng ru anh hng n tc phat trin cua nm men con phu thuc vao thi gian, s lng t bao va mi trng chun bi nui cy. Cung mt mi trng nui cy, s lng t bao nm men cho vao la nh nhau, iu kin cy ging nhau thi nng ru 1% cha co anh hng n tc va kha nng phat trin cua nm men, t 4 6% a co anh hng xu.

2.7.7. Anh hng cua ngun nit.

a s trong nc qu c cc hp cht nit cung cp cho nm men. Tuy nhin cng c trng hp khng ngun nit, do cn b sung thm ngun nit. Trong trng hp ny ngi ta thng dng amon sulphat (NH4)2SO4. Cng c th dng men t phn cho thm vo mi trng. Nu dch qu qu chua dng tartrat amon-kali hay amon hydroxy trung ha bt acid.

i vi dch nhn ging hoc hot ha ging th hn hp cc ngun nit v cc cht sinh trng rt c ngha.

2.7.8. Anh hng cua mt t bao nm men.

S lng t bao cho bao cho vao dich ln men co anh hng ln n qua trinh ln men. Nu s lng t bao nm men cho vao la thich hp thi qua trinh ln men tt va hiu sut thu hi cao, cht lng san phm tt. Nu lng t bao nm men cho vao qua it thi qua trinh ln men chm, sinh khi t bao nm men thp tao iu kin cho vi sinh vt phat trin. Nu lng nm men cho vao la qua nhiu thi lng dich ln men khng u cho t bao nm men phat trin, t bao nm men se cht dn, san phm sinh ra se co mui la ng thi phi i mt lng nm men.2.7.9. Anh hng cua cht sat trung.

Cac cht sat trung dung trong san xut nh: formon, Na2SiF6, NaF, CaOCl2..., cac mui kim loai nng hay tia cc tim u co anh hng n hoat ng cua nm men. Tuy nhin, mi mt cht co mt anh hng khac nhau trong tng mi trng va tng chung nm men khac nhau. Cht sat trung c dung ph bin nht trong san xut ru vang trn nhiu nc trn th gii la SO2, no co tac dung nhiu mt nh: chng oxi hoa, lam giam hoc tiu dit cac loai vi khun trong o co vi khun lactic. Lng SO2 thng dung la 30 120mg/l, SO2 co tac dung lam t lit cac enzim oxi hoa kh. Nu dng qu liu lng cho php s lm cho ru vang c mi kh chu v dit mt s vi khun c ch. Ngun SO2 s dung ph bin trong u ru vang la hp cht Na2SO3.

2.7.10. Anh hng cua ham lng CO2.

Ham lng CO2 hinh thanh trong qua trinh ln men thng han ch manh s sinh san cua nm men. Theo nghin cu cua Muiler-Thurrau, khi:

Ham lng CO2 trong ru vang at n 0.25% trong lng thi vic sinh san nm men ngng tr.

Ham lng CO2 trong ru vang at 1.5% trong lng thi nm men khng con sinh san na.

Vi ham lng CO2 nh trn, nhit 150C, ap sut 7.7 atm, nm men vn sng va tip tuc ln men ky khi.

III. KT LUN V KIN NGH.

Thng qua tm hiu v nm men v ng dng ca chng trong sn phm ru vang, ti nhm nghin cu tng quan v nm men v ng dng trong cng ngh thc phm, bn cnh trng tm ti i su vo nghin cu v nm men trong ln men cc sn phm ru vang, v cc chng loi, c im sinh hc ca chng t rt ra cch bo tn v pht trin cng nh s dng mt cch tt nht cc chng nm men trong tng trng hp ln men c th em li hiu qu ln men tt nht. Nghin cu c im hnh thi, sinh l v kh nng to bo t ca cc chng nm men ru vang, chng ti nhn thy mi trng acetat l thch hp cho s to bo t nhit 25oC.

Nghin cu kh nng ln men v to cn ca cc 18 chng nm men, chng ti rt ra mt s chng nm men thng c dng trong cng ngh ln men vang l: Saccharomyces cerevisiae, Saccharomyces uvarum, Saccharomyces chevalieri, Saccharomyces oviformics, Hanseniaspora apiculate Kloeckera apiculata.

TI LIU THAM KHONghin cu cng ngh v thit b sn xut ru vang cht lng cao Ch nhim ti cp nh nc PGS.TS Trng Th Ha.Bo co ti Quy trnh sn xut ru vang GVHD: PGS.TS Trn Th X.

Nm men cng nghip Lng c Phm.

Vi sinh vt cng nghip L Xun Phng.www.nhasinhhoctre.com http://vi.wikipedia.org/wiki/R%C6%B0%E1%BB%A3u_vang4