Sa chua

Bi tp:Tm hiu vi sinh vt c trong sn phm thc phmSa chuaSa chua c to ra nh s dng ging khi ng l Streptococcus thermophilus v Lactobacillus bulgaricustheo t l 1:1. S phi hp hi ha 2 chng vi khun ny, trong acid c to ra nhS.thermophilus, cn hng liu li c to ra nh L.bulgaricus s to ra sn phm cui l sa chua c cha 109vi khun trn 1 gam.Streptococcus thermophilusVai tr: bin lactose, mt loi ng c trong sa thnh acid lactic trong iu kin k kh.Vi khun axit to ra chu trch nhim cho hng v chua v kt cu ca sa chua.

i vi nhng ngi bt dung np Lactose mc va phi th c th n sa chua v cc khun sng trong sa b gy lactose thnh glucose v galactose 2 ng n d tiu ha. c imC dng hnh cu, kt thnh chui di, pht trin tt nht nhit 40-450C, vi khun gram dng , l mt loi vi khun axit lactic

Lactobacillus bulgaricusT bo c hnh gy ln, i khi dng ht ng ring r hoc thnh chuiL trc khun trn, Gram dngKhng c kh nng di ng.

Khng c kh nng to ra nitrit t nitrate. Nhit ti thch hp cho pht trin l 40-450C, ti thiu l 15-200C.Phomat Lactobacillus helveticusL trc khun. Tn ti ring l tng t bo hoc to thnh chui t bo.Nhit pht trin t 40-420C Vai tr: ngn chn s cay ng v to ra hng v hp dn trong ph mai.

C kh nng ln menfructose, galactose, mannose, maltose, lactose. cc loi ng glucose,Lactobacillus delbrueckirTrc khun diKch thc rng 0.5-0.8um , di 2 .0-9.0 mm, khng di ng, Gram (+)C kh nng ln men c cc loi ng glucose, fructose, galactose, maltose v dexrin.C th ng ha c tinh btVai tr: to acid lactic trong qu trnh ln men gp phn gy ng t sa v to chua cho khi ng.PropionibacteriaPht trin chm, Gram dng, vi khun k kh.Hnh dng que hoc mch nhnh, tn ti theo cp hoc theo nhm.To ra axit lactic, axit propionic v axit axetic t glucose.

Vai tr: c s dng trong giai on chn trong mt s loi phomat to nn nhng l hng trong cu trc mt s ph mai cng v gp phn to nn hng v c trng cho sn phm.BTrong sn xut b ln men, ngi ta s dng vi khun lactic LD. Thng gp nht l Streptococcus diacetylactic v Leuconostoss citrovorum. Trong qu trnh ln men, ngoi acid lactic, chng sinh tng hp cc hp cht d bay hi aldehyde acetic, diacetyl, acetoin Cc hp cht ny s to cho sn phm b hng v c trng.Streptococcus diacetylacticT bo thng ng ring r hoc xp thnh i hay thnh chui, l cu khun Gram (+), v bng polysaccharide,Pht trin tt 350C. Do vi khun ny c enzim xitritaza nn mi c th ln men c axit xitric. Vai tr: to thnh axit lactic v lm ng sa sau 16-48 gi, to thnh diaxetyl nn to ra hng v d chu cho b

11Leuconostoss citrovorumLn men acid citric ca sa vi s sn sinh cht c mi thm diacetyl v kh nng kch thch lin cu khun lactic lm cho chng c em dng vo giai on u ca ch bin b v phomai.

Leuconostoc citreum12

Bnh mMen l cc loi nm n bo, c s dng gip cho s ln men ca bnh m hay trong sn xut cc loi ung cha cn. Saccharomyces cerevisiae l tn ca nm men ni ting nht, c s dng rng ri trong vic sn xut bnh m.Saccharomyces cerevisiae T bonm menSaccharomyces cerevisiaec dng hnh cu hay hnh trng, c kch thuc nh, t 5-6 n 10-14m,sinh sn bng cch to chi v tobo t. Vai tr: lm tng lng kh CO2 tch ly ru mc ti thiu v gp phn vo hng v c trng ca bnh m.

ChaoSn phm ln men c sn xut t u nnhQu trnh ln men u ph, cc enzym vi sinh vt tham gia qu trnh thy phn protein to thnh cc acid amin, lipit thnh cc ester thm nn chao c gi tr dinh dng cao v c mi v c trng.Vi sinh vt trong sn xut chao thng c hot proteaza v amylaza cao: nm mc Mucor elegans, M.hiemails, M.praini, vi khun Bacillus subtilis.

Bacillus subtilis

Bacillusn l c hnh dng ging nhng chic que, phn ln nhng chic que ny cbo t trong hnh oval c khuynh hng phnh ra mt u. Vai tr: sinh ra nhiu enzyme, trong nhiu nht l cc men tiu ha amylase v protease.Tc dng: chng ng mu, kch thch h min dch c dng lm thc phm chc nng b sung h vi khun c ch v cc men tiu ha c li cho ng rut.

Nm mc MucorMc Mucor c khun ty n bo phn nhnh mnh, sinh bo t .Chng mc cc loi ht, thc n gia sc, thc phm b m thnh mt lp lng t mu xanh.Mt s Mucor c kh nng ln men ru v oxy ha. Chng c dng trong sn xut acid hu c v ch phm enzym

Nc mmSan phm ln men t ca, la hn hp cua cac axit amin. Cac a.a nay c tao thanh do s thuy phn cua proteaza. Cac proteaza nay do vi sinh vt tng hp nn.Vi sinh vt trong nc mm la nhng vi khun thuc Bacillus subtilis, B.mensentericcus, Escherichia coli, Pseudomonas sp, Clostridium sp.

Vai tro: tham gia vao qua trinh thuy phn protein, tham gia vao vic hinh thanh hng vi cua nc mm, co kha nng sinh hng, co hoat lc proteaza cao.Vic s dung ch phm proteaza cua vi sinh vt lam rut ngn thi gian ln men cua nc mm.

Pseudomonas spc im l: Gram m, t bo hnh que, di ng nh roi u v khng c bo t. Cc c im sinh l l d dng, khng ln men, linh hot v dinh dng, khng quang hp hoc c nh nitrogen.Phn gii tinh bt, phn gii phosphat.

Nem chuaVi sinh vt: vi khun lactic thuc Lactobacillaceae streptococcus, L.pediococcus, L.lactobacillus, L.leuconostoc.Vai tro cua vi sinh vt: tao ra hng vi cho nem, tao cam giac d chiu khi n, tao ra cht lng nem. Sinh tng hp bacteriocin co kha nng khang khun cao.

c im: vi khun Gram dng, khng tao bao t, khng di ng h hp tuy tin va khng cha cac men h hp, sinh san bng hinh thc nhn i.Tc hai: vi khun lactis phat trin gy thi nem.

Rau, c, qu mui chuaQua trinh ln men lactic do vi khun Leuconostoc mesenteroides, Lactobacillus plantarum, Lactobac brassicae fermentatiVai tro cua vi sinh vt: co kha nng sinh ra cac cht, cac hoat tinh khang sinh, c ch vi khun phn huy peptides hoc protein.

c im cua vi sinh vt: la nhng trc khun, cu khun khng tao bao t va hu ht khng di ng h hp tuy tin, co kha nng ln men nhiu loai ng n va ng i.Tac hai: s phat trin cua cac tap khun gy hin tng rau qua bi thm, hin tng nc co mang do nm mc va nm men (Mycoderma, Aspergillus, Torula, Oidium lactis, Penicilium).

THNH PHN VI SINH VT TRONG LN MEN H VI SINH VT C LI TRONG LN MEN RU VANG T NHIN

VI KHUN: - Vi khun thuc ging: Bacillus, Pseudomonas, Microcicus, v vi khun acetic thuc ging Acetobacter. NM MC:- Nm mc thuc ging: Aspergiluss, Penicillium, Rhizopus, Botrytis NM MEN: - C 4 loi nm men khc nhau: Hanseniapora, Metschnikowia,hensenula v CandidaNM MEN THNG S DNG TRONG LN MEN RU VANG- Saccharomyces vini ph bin trong ln men ru vang chim 80% trong tng s Saccharomyces + t bo hnh ovan, sng dng bi hoc dng bng + Sinh sn: ny chi v to bo t

+ C enzym invertase c kh nng kh ng saccharose thnh glucose v fructose + Kh nng to ru: 8 -10% so vi th tchSaccharomyces-Saccharomyces uvarum+ Hnh thi: khng khc vi cc loi khc+ cn: 12-13% so vi th tch

NM MEN THNG S DNG LN MEN RU VANG

-Saccharomyces chevalieri + Tch ra t nc nho ln men t nhin dng gy men nc da hoc nc c + cn : 16 o - Saccharomyces oviform + u im: pht tt trong nc nho v cc loi tri cy khc chu c cn cao, ng cao v to cn n 18o + Nhc im: khng ln men c galactose c im chung: nhit thch hp pht trin 18 - 25oC, c ch sinh sn nhit 35oC, 40oC ngng sinh snVI KHUN

- Vi khun lactic: c th to mi hi do s phn hy lysine to ra histamin, t histidine v cc amin khc gy nhc u. Vi khun lactic cng to ra CO2 lm hng cht lng ru gy n hoa lm c ruTHNH PHN VI SINH VT GY HI CHO CHT LNG RU VANG LN MEN

29Vi khun acetic: ch yu l Acetobacter aceti, c th pht trin sau khi ru c ng chai nu nt chai khng tht cht, to acid acetic gy v chua.

- Streptomyces: Gy mi t cho ru

- Bacillus: Gy mi kh chu v gy c ru

Streptomyces platensis

Bacillus bacteria2. NM MENZygosaccharomyces, Pichia: lm c ru vang v to mi lm nh hng n cht lng ru.

Zygosaccharomyces rouxii

Pichia fermentans Brettanomyces/ Dekkra : to ra mi kh chu do hp cht vinyl phenol sn phm phn hy amino acid v cc sn phm oxy ha cc hp cht aldehyde ca thng g ng ru vang Saccharomyces: lm c ru, si bt do CO2

Brettanomyces bruxellensis

Saccharomyces Cerevisiae3. NM MC: vi sinh vt hiu kh nhy cm vi ethanol v sulfite. Nm mc c th to ra cht 2,4,6 trichloranisole c tnh cht ging nh bn

Cm n C v cc bn lng nghe bi thuyt trnh ca nhm!