Thức Uống Lên Men Lactic Từ Gạo Lức

e ti: Th nghim to thc ung ln men lactic t- go lc


CHNG 1. M ULn men ng dng rt rng ri trong ch bin thc pham, sn phm ca ln men gp phn lm gia tng gi tr dinh dng, cht lng v an ton cho sn phm. c bit, ln men lactic l loi ln men c ng dng rng ri v to ra nhiu sn phm c gi tr. C nhiu loi thc ung truyn thng c ln men lactic t' ng cc nh Boza ca Th Nh K, Rumani, Bulgari... Kunun zaki ca Nigeria, Sobia ca Rp Saudi... Cc loi ung ny khng cha cn, c v chua ngt, giu dinh dng v nng lng [15].Ngy xa, con ngi bit s dng ln men lactic to ra nhng loi thc ung b dng. Sau con ngi nghin cu v vic b sung h vi sinh vt trong qu trnh ln men nhm ci tin v lm gia tng qu trnh ln men, lm cho sn phm ln men ngy cng hon thin hn. Gn y, con ngi cn b sung thm cc ch phm c li nh: Probiotic, Prebiotic, Bactoriocin vo thc ung lm gia tng gi tr dinh dng ca sn phm, tt cho h tiu ha v tng cng sc khng cho c th. iu ny m ra nhng bc ngoc mi quan trng v vai tr to ung nh ln men lactic.Go lc t lu c nghin cu l mt loi go cha nhiu cht dinh dng, c kh nng chng li c nhiu bnh. Hin nay, nhng sn phm ca go lc ang c s dng rng ri nhiu nc trn th gii, ngi Vit Nam xem go lc nh l mn n cha bnh [13]. Vic ln men go lc vi vi khun lactic cng c Nht Bn v Hn Quc kho st. Vi nhiu loi go lc khc nhau, sau khi ngm, s lng vi khun lactic u gia tng r trong nc v go, ngn chn s pht trin ca nhng vi sinh vt khc. H to loi ung tng t Amazake t s ln men Lactobacillus amylovorus vi c cht go Koji.T gi tr ca ln men lactic v thnh phn ca go lc mang li l c s cho cc nghin cu cho ra sn phm nc ung ln men t go lc, sn phm ln men bi Lactobacilus acidophilus da trn c cht go lc. ti Th nghim to thc ung ln men lactic t go lc nhm to ra sn phm nc ung mi a n cho th trng thc phm trong nc p ng yu cu ca ngi tiu dng cung cp nhiu cht dinh dng cn thit.CHNG 2. TNG QUAN TI LIU2.1. Gii thiu v go lc2.1.1. Gii thiu chung v ht go Vit Nam, thc go l thc phm chnh ca nhiu dn tc, khng phi nh nhiu ngi c ngh rng n nhiu tht, nhiu ng mi tt v coi l thc n chnh. Dn tc ta c cu ca ming ba cm, n cm th hin y cm go l thc n chnh. l thc n m dn tc ta cng nh nhiu ni trn th gii s dng sinh tn hng ngn nm nay. T lu chng ta ch quen n loi go trng m t ngi n loi go no b dng, p ng nhu cu c th, ph hp vi sinh l, vi c th ca con ngi hn.Nhng nm gn y, qua phn tch cht go, c bit l go lc, ngi ta thy khng nhng c nhng cht ch yu nh m, bco, bt m cn c nhiu loi sinh t, cc cht khong, cc loi acid, cht x v nhiu cht khc, cng thy r tnh cht u vit v kh nng b dng, phng v cha bnh ca go lc trong cy la. Th nhng go em gi xt tht trng ch cn li cht bt, mt i 1/3 hoc c khi mt ht cc cht dinh dng thin nhin. Do n thun go trng d pht sinh nhng bnh v thiu cc cht k trn.Go khng ging a s cc ng cc khc l ht c tiu th ton b. Bi vy nhng tnh cht vt l nh kch thc, hnh dng, s ng u v cm quan chung l v cng quan trng. Hon na, a s go trc khi s dng phi qua xay ch, do thuc tnh vt l quan trng xc nh ch yu bi ni phi nh. Trong trng hp thun khit, cht lng go nh hng bi c tnh do gen iu khin, cc iu kin mi trng v cc cng ngh ch bin. Trong trng hp nh hng do ch bin, cc c tnh chi phi l tn tr v phn phi. Kiu gen ca mt ging c th c ch mc ln cc c im cht lng ht. Nhng nh lai to ging v di truyn hc tip tc ci thin gen ca cc ging mi to ra sn phm mong mun. S chn lc ch trng ci thin cht lng xay ch, nu, n v ch bin l nhng thnh phn ch yu ca chng trnh to ging da trn nn tng ca cc tiu chun cng nghip. Quan tm gn y trong vic to ra ging cht lng cho th trng xut khu l ktqu trong s la chn hng v c bit v cc c im nu n c a thch bi ngi tiu th.2.1.1.1 Cht lng ht goSau nng sut ht, cht lng ht go l quan trng nht. Go xay vi ht trong m nguyn ht c a thch. Vng b m c trong mt ni nh trong m c gi l bc bng.Go c v s kiu chiu di ht khc nhau. Bng sau a ra phn loi tiu chun kch thc ht.Bng 1: Phn loi cc tiu chun ht goKch thcChiu di (mm)Cp Hnh dngT l di/rngCp

Di nht>7.51Thon>3.01

Di6.61-7.53Trung bnh2.1 -3.03

Trung bnh5.51-6.65Hi trn1.1 -2.05

Ngn- 5.57Trn- 1.17

[49],

Kiu ht hi thon, hi trn, v trn, khng bc bng khi ch vi m 14% t b gy v c nng sut go nguyn cao. T l go xay v mu sc ca go rt quan trng, cc ging khc nhau c kiu v cng mi thm khc nhau. Hong thm trong go l do cht ha hc diacetyl - 1 - pyroproline to nn. Cht lng go nu v n thay i theo vng. Go xay c ht trong m, thon di c hoc khng c mi thm, c n nhiu khi nu (do s kco di nhn ht), c tnh mn (khng dnh v mm), cu trc ht chc, mi v hp dn v thi hn s dng ko di c a chung trong th trng ni a cng nh th trng quc t. Hnh di y trnh by cc kiu ht di, trung bnh v ngn in hnh ca M.Trong ct u tin bn phi (1 n 3) l kiu ht la (rough rice or paddy rice). Ct gia (1 n 3) l go lc hay go cha qua nh bng (brown rice or unpolished rice). Ct cui bn tri (1 n 3) l go trng (milled rice/white rice/head rice). Mi loi bao gm c dng ht di, trung bnh v ngn.

Hnh 1: Cc loi go di, trung bnh, ngn in hnh [35].Mu ca v cm: Mu v cm bao gm mu trng nu sng, nu ti, nu, , tm sng v tm.Mc bc bng: Mc bc bng ca ht go c chia nh sau:Cp 0: khng bc bng.Cp 1: vng bc bng t hn 10% trong ht go.Cp 5: din tch bc bng trung bnh 11 - 20%Cp 9: hon 20%.

Hnh 2: Mt s loi go lc [36].

Thnh phn ht go sau khi xay ch gm c v tru, cm, go lc, go ch (head rice) v chim 67 - 70% trng lng ca ht go.Go trng chia thnh hai phn: Go nguyn v tm (go b gy). Go nguyn chim t 40 - 60% trng lng la em ch v ph thuc iu kin, k thut sau thu hoch, i khi t l ny di 40%. Phn trm go gy thay i tng ng vi t l go nguyn.Cht lng xay ch: Yeu t ny bao gm phn trm go lc, go trng v go nguyn.Trng lng ht la khng vGo lc (%) = X 100Trng lng laTrng lng go sau khi ch v nh bngGo trng (%) = X 100Trng lng laTrng lng go nguyn (khng gy)Go nguyn (%) = X 100Trng lng laTrung bnh phn trm v ht t 18 - 26% trng lng la, ph thuc vo ging c v dy hay mng. Go trng chim khong 70% nhng thay i do nhiu iu kin nh ging, mi trng v cng ngh sau thu hoch. Trn th trng yu t quan trng l phn trm go nguyn v thay i t 25 - 65%.2.1.1.2 Cc tiu chun nh gi cht lng goCht lng cm: Cht lng go c nu gm hm lng amylose, nhit tr h v bn gel.Tiu chun Quc t hm lng amylose nh sau:0-2% go do2 - 20% go mm (hm lng amylose thp)20 - 25% go mm (hm lng amylose trungbnh)>25% go cng (hm lng amylose cao)Nhit tr h (GT)l c tnh chnhit nu go thnhcmvkhngthtr li trng thi ban u. GT thay i t 55- 79c.GT trung bnhliu kintiho cho cht lng go tt.GTthp55 - 69cGT trung bnh69 - 75cGT cao75 - 79c bn gel: Tiu chun Quc t cho bn gel da vochiu digel.Trongnhm go, cc ging c cng hm lng amylose nhng bngel caohnc achung hn.80 - lOOmmmm

61 - 80 mmmm

41-60 mmtrung bnh

36 -40 mmcng

< 35 mmcng

Cht lng dinh dng v hng v:Hng v: V ngon hoc hng thm trong go c to bi ha cht diacetyl 1 - pyroproline. nh gi tiu chun theo Vin Nghin cu la go quc Te (IRRI) c chia lm 3 mc :Khng thm t thm Thm nhiue ti: Th nghim to thc ung ln men lactic t- go lc

Cht dinh dng: Tinh bt cao nht la m 81,1%, tip l go 74,8% v thp nht trong cy la min 67,4%. Thnh phn quan trng th hai trong go l protein vi 8,5% trong khi trong cy k cao nht vi 13,4%. Ni chung, dinh dng trong ng cc ngho lysine v threomine. Cht lng protein trong go cao nht bi v c lysine cao 3,5 - 4% hon ng cc. Trong nhng nm gn y, vin nghin cn lng thc v thc phm Vit Nam thnh cng trong vic pht trin ging c hm lng protein cao 10% nh cc ging P4 v P6. st v vitamin thiu nghim trng nhng vng ngi ta ch yu tiu th go, st c rt t trong go [17].GVHD: TS. NGUYN THY HNG1SVTH: NGUYN TH QUNH LY

e ti: Th nghim to thc ung ln men lactic t- go lc2.1.1.3 Go lcGo lc l loi go chi va mi bc i lp v tru, vn cn lp cm bao bc bn ngoi. Neu gi sch lp cm ny s cho ra go trng l loi chng ta n hng ngy. Lp cm ca ht go lc cha nhiu dng cht quan trng nh: vitamin E, vitamin Bl, B3, B6, magi, mangan, cht x, st... [37].

Hnh 3: Go lc [38].Go lc gm c ba loi: go lc t ht di (long grain brown rice), go lc t ht trn (short - grain brown rice), v go lc np (sweet brown rice).Go c phn loi theo b di ca ht go :Go ngn 6,5 mmTt c go lc u b dng, nn cn c n trong cc ba n hng ngy. Mc du thi gian nu go lc lu khong 45 pht, nhng c th nu mt ln cho mt tun th cng tit kim c nhiu th gi.Go lc l mt loi thc phm nhiu dinh dng khi so snh vi go trng. Tuy nhin, n cn gia tng nhiu dinh dng hn na khi c em ngm trong nc m, lu khong 22 gi.e ti: Th nghim to thc ung ln men lactic t- go lc

y l mt khm ph mi nht ca khoa hc. Go lc khi ngm lu cha rt nhiu cht b dng v go lc trng thi ny mm. Cc enzyme ng trong ht go trng thi ny c kch thch hot ng v cung cp ti a cc cht dinh dng [17]. Theo Hiroshi Kayahara, gio s khoa sinh hc v k thut sinh hc ti vin i hc Shinshu University in Nagano, ni nh vy trong bi tng trnh ktGVHD: TS. NGUYN THY HNG#SVTH: NGUYN TH QUNH LY

GVHD: TS. NGUYN THY HNG11SVTH: NGUYN TH QUNH LY

qu nghin cu ca nhm ng ti Hi ngh ho hc quc t Hawaii vo cui nm 2000 va qua. Mm go lc cha nhiu cht x, vitamin v cht khong hn l go lc cha ngm nc. Kayahara vit trong t trnh, go lc ngm nc cha gp ba ln lysine, mt loi amino acid cn thit cho s tng trng v bo tr cc m t bo c th con ngi v cha nhiu hon mi ln chat gamma - aminobutyric acid, mt chat acid tt bo v b phn thn (kidneys). Cc khoa hc gia cng tm thy trong mm go lc c cha mt loi enzyme, c tc dng ngn chn prolylendopeptidase v iu ho cc hot ng trung ng no b. Go lc ny mm khng nhng ch em li nhiu cht dinh dng m cn nu rt d dng v cung ng cho chng ta mt khu v hi ngt v cc enzymes tc ng vo cc cht ng v cht m trong ht go.Go lc b dng hn go trng nhng kh tiu hn v lp cm ngoi cha nhiu chat celuloze rt cng.Go lc c th khong 4-5 thng. Neu lu, cht du trong lp cm s b h, go s c mi, khng th s dng c. Nn ct go ni thong mt.2.1.2. Thnh phn chnh c trong go lcHt la c cu to gm:V tru: V ngoi cng, c nhiu silic, thng dng t l. Gia sc khng n c tru... ngoi tr g vt.Cm: Cm c nhiu lp t bo nm ngang, cha cht bo, sinh t, cht m, to mu sc cho go.Lp cm ca ht go lc cha nhiu dng cht quan trng nh: vitamin E, vitamin Bl, B3, B6, magi, mangan, cht x, st...Li: Khi ch xt, b cc lp ngoi, ht go cn li li cha t bo tinh bt v cht m.Mm thc: cha nhiu cht m v cht bo.Thnh phn ca go lc gm c cht bt, cht m, cht bco, cht x cng cc vitamin nhm Bl, B2, B3, B6 v cc acid pantotenic, acid paraaminobenzoic, acid polie, acid phytin, chat canxi, chat st, chat magi, chat selen, glutathion, kali v natri.Ty tng phn ca ht go m c cc thnh phn ha hc khc nhau:Bng 2: Thnh phn ha hc ca ht goTnccphnProtein(%)Tinhbt(%)ng(%)Cellulose(%)Pantozan(%)Chtbco(%)Tro(%)Cc cht khc(%)

Ton b ht10,0759,004,432,768,102,242,181,22

Ninh12,9179,563,540,152,720,670,45-

Phi41,3Rt t25,122,469,7415,046,310,03

V28,7Rt t4,1816,232,567,7810,510,07

[1]-

Go lc v go trng gn ging nhau v lng calories, carbohydrate, cht bo v protein nhng mt so vitamin nh Bl, B3 v cht khong nh st b mt trong qu trnh xay xt [ 13 ].Cc nh khoa hc tm thy trong cht cm bc ngoi ht go lc c cht du tn l tocotrienol factor (TRF) c tc dng kh tr nhng cht ha hc gy nn hin tng ng mu v ng thi gim cholesterol. Ngoi ra, trong cht cm bc ngoi go lc cn c thm mt cht khc c kh nng chng li cht xc tc enzyme HMG - CoA, mt cht c khuynh hng gip gia tng lng cholesterol xu LDL. Trong lOOg bt mm go lc cha:Sinh t BI (2,83 mg%) hiu qu vi chng thiu sinh t v bnh t ph.Sinh t B2 (0,56 mg%) lm p ngi.Sinh to B6 (5,30 mg%) cha bnh thn kinh, mt ng.Sinh t E (17,60 mg%) lm tr li v cng tinh.Cht nai - a - min (6,80 mg%) phng lot d dy mn tnh.Acid pangtotenic (0,82 mg%) nhn t ay mnh s trng thnh.Acid nicotinic (20,64 mg%) lm mu trong sch, da d mn mng.Ngoi ra, cn c sinh to B12 hiu qu i vi chng thiu mu, glu -ta - xion phng chng ngi phng x nng, c acid glutamic cha chng nhc u, cthnh phn st lm cho mu tr nn trong lnh, c cc cht khong nh can - xi,v.v...c bit protein ca go lc khng c prolamin v do khng c gluten. Trong qu trnh ch bin, thnh phn ca go c s thay i.Bng 3: Thnh phn ha hc ca go lc xayTn sn phmHm lng % theo cht kh

ProteinCht boTroCellulose

Go xay nguyn (go lc)8,761,871,420,84

2.1.3. Cc sn phm ca go lc2.1.3.1 Nc ung t go lcQuy trnh c thc hin nh sau:

ng haCy gingLm nguiTit trngLn menRt chai

Thanh trngBo qun

S 1: Quy trnh to thc ung ln men t go lc [39].

Ra sch tp cht, dng my xay truyn thng (hai tht thng ng) hay my xay kiu mi, hoc my xay sinh t xay, lng nc khi xay bng 3 - 5 ln lng go.Tin hnh lc s b qua lp vi lc nhm loi b mt phn tp cht.B sung nc vi t l nht nh ri gia nhit ln 100c trong 45 pht. Sau , em dung dch i xay mt ln na.Cui cng l, cng on lc tinh nhm gip cho sn phm khi hon thnh c mu sc trong v loi b hon ton cc tp cht. ng v pectin vo nc, ha tan hon ton dung dch v lc qua tm vi loi b phn cn.Ly phn dch b sung vo dch go sau khi lc xong vi mt t l nhtnh.Dch nc go sau khi ln men xong, th em b sung thm ng, hng liu v mt s mu thc phm thch hp tng tnh cm quan ca sn phm.Sn phm sau c em i rt chai trong iu kin v trng tuyt i. Trc khi rt chai, dch go phi c kim tra cc ch tiu ha l v cm quan.Ch thanh trng thng l 75 c trong vi pht. Nu thanh trng qu mc c th lm mt mu, mt mi sn phm v cc vi sinh vt c li.Sn phm cn c bo qun nhit t 4 - 6c trong t lnh.Qu trnh ln men c th chia lm 3 giai on:Giai on u: 0-80 gi ch yu l sinh khi, ng tiu hao chm, acid lactic tch t t.Giai on 2: 80 - 135 gi l giai on to acid lactic mnh nht, v vy lng ng tiu hao rt nhanh.Giai on 3: l giai on ln men cui cng ca sn phm, tc ln men chm v lng acid sn sinh ra nhiu c ch li s hot ng ca vi khun lactic [40],2.1.3.2 Go lc mui mPhng php iu tr bnh tt bng cch n "go lc, mui m" c gi l "phng php thc dng" (Macrobiotics), ra i bi gio s ngi Nht c tn Sakurazawa Nyoichi m by gi, ngi ta vn quen gi l phng php Oshawa.Phng php ny khng chi c p dng cc nc phng ng m cn c bit n mt s nc phng Ty.Vi nc ta, cc bc s nghin cu p dng phng php ny cho bit, vic n go lc mui vng gip nhiu ngi cha khi bnh mn tnh m khng cn dng n thuc. Mt s ngi p dng bin php ny trn 10 nm, c ngi trn 20 nm m khng thy biu hin thiu cht.Cht selen c y hc chng minh rng c kh nng ngn nga ung th, cht glutathion th phng nhim bi phng x, acid pantotenic gip tng cng chc nng ca v no, chng vim da, u bu c tnh nn vic duy tr mt ch n gm ton go lc, mui m phng nga v cha bnh ung th l c c s. Vit Nam, phng php thc dng bng go lc, mui m bt u xut hin vo khong nm 1963 [41].2.1.3.3 Go lc rang2.1.4 Gi tr dinh dng ca go lcNhng ch li cho sc khe ca go lc bt u vi cht x ca n, 300g go lc cung cp khong 14% gi tr dinh dng hng ngy ca cht x, c chng minh l c th gim lng cholesterol. Ni cch khc go lc dng chng x va ng mch. Cht x cng c th gip c th bng cch gi cho mc ng trong mu di mc kim sot, do go lc l mt la chn ng cc tuyt vi cho ngi b tiu ng.Nhiu nghin cu khoa hc chng minh rng trong lp cm ca go lc cha mt cht du c bit c tc dng iu ha huyt p, lm gim cholesterol xu, gip ngn nga qua cc bnh v tim mch. c bit, i vi ph n, n lm gim nguy c ung th v rut kt, gim cholesterol v tt cho h tim mch ca ph n sau mn kinh.ng thi, vi ngun cht x di do, go lc gip chng li bnh x va ng mnh, ung th v, gim nguy c mc bnh tim, ung th v bnh tiu ng.Cm l lp v ngoi mu nu ca ht go c s dng qua nhiu th k trong k thut chm sc da. Cc thnh phn chnh c trong go gm:Acid cm go: Cm go cha n 10% canxi ion gip ni lng s lin kt gia cc t bo cht xn mu trn b mt da. ng thi chng kim sot v ngn nga cc m nu xut hin do tui tc.Tocopherols/tocotrienols: Cc dn xut vitamin E v thnh phn hiu nghim khc gip bo v da khi cc tc ng xu ca mi trng v lm chm qu trnh lo ha.Proanthocyanidins: Cc cht c ch enzyme gip bo v s lin kt v n hi ca da, gip da gi c s mm mn v sn chc.Nhng ht go lc s b sung thm cc loi vitamin nhm B, kim sot lng ng trong mu v lm cho tnh kh d chu hn.Nghin cu dc l thc nghim cho thy cm go c tc dng bo v chng vim dy thn kinh v tr cc bnh v da. Cm tinh thu c sau khi ch xt go c tc dng lm tng huyt sc t trong mu, chng thiu mu. Th nghim lm sng trn ngi cho thy hot cht trong du cm go c tc dng lm h nng cholesterol trong mu. Du cm go l mt hot cht chit t cm go c tc dng chng ung th, c th do kh nng kch thch hot tnh min dch ca c th bnh nhn ung th.Cht x cn c tc dng gip no lu nn khi n cm go lc, bn s khng b tng cn.Theo nhiu nghin cu khoa hc cho bit cht x trong go lc gip phng nga cc bnh lin quan n ng tiu ha v bnh tim mch. Vin Ung Th Quc Gia Hoa K khuyn co nn dng 25 grams cht x mi ngy. Vi 300g cm go lc cung cp 3,5g trong khi cm go trng ch cho c lg.n go lc thng xuyn gip c th do dai, gn ct cng cp, hot bt, au nhc xng khp. nhng ngi b tha cn (bo ph), nu dng go lc lu di s gim cn v cng gin tip trnh c bnh tiu ng [43].i vi nhng ngi lo lng v nguy c mc bnh ung th trc trng, go lc c tc dng gp 2 ln v n l ngun cha lng cht x cn thit gia hn ti a thi gian cc cht gy ung th tip xc vi t bo trc trng. l do cc cht x ny rng buc nhng ha cht gy ung th, cch li chng khi nhng t bo gn trn rut kt, ng thi gip bnh thng ha chc nng rut, gim chng to bn hay bnh tiu chy nhng ngi mc hi chng rut kch thch (IBS).Tc dng ca selen c trong go lc.Ngoi vic cung cp 14% lng cht x cn thit hng ngy, mt chn cm go lc cn cung cp 27,3% lng gi tr dinh dng hng ngy i vi selen. y l mt li ch quan trng v selen l mt vi khong quan trng thit yu cho sc kho con ngi.Cht selen l thnh phn thit yu ca mt vi con ng trao i cht trong c th, bao gm s trao i chat hormone tuyn gip, h thng phng chng s oxi ho v h min dch. Cc th nghim nghin cu trn mu ng vt cho thy r rng l gia lng selen a vo c th v nguy c mc phi ung th c mi lin quan t l nghch vi nhau. Selen gip thc y s phc hi v tng hp ADN trong cc t bo b ph hu, ngn chn s sinh si ca cc t bo ung th, gy ra cc phn ng d ng ca n, kt qu s t ph hu ca c th i vi cc t bo m yu hay bt bnh thng.Selen kt hp cht ch vi cc cofactor nh glutathione peroxidase rt quan trng i vi qu trnh chng ung th. Khng nhng th, n cn kt hp vi vitamin E trong rt nhiu h thng chng oxi ho thit yu cho s sng ca c th ngi. Cc hot ng chng oxi ho mnh m ny ca selen khin cho selen rt hu ch trong vic phng chng khng ch ung th m cn c nguy c au tim, cng nh lm gim cc triu chng ca bnh hen suyn, cc cn au v sng khp.Tc dng ca man gan c trong go lcTo nng lng v bo v qu trnh chng oxy hoCh cn mt chn cm go lc cng cung cp 88% lng man gan cn thit hng ngy. Vi cht khong ny gip to nng lng t protein v carbonhydrat, tham gia vo qu trnh tng hp acid bo rt cn thit cho mt h thn kinh kho mnh cng nh qu trnh sn xut cholesterol cn thit cho c th sn xut ra cc hormone gii tnh.Mangan cng l thnh phn chnh ca 1 loi enzyme chng oxi ho rt quan trng tn l superoxide dismutase (SOD). SOD c tm thy ty th trong t bo ca c th gip ngn chn nh hng xu ca cc gc t do c gii phng trong qu trnh gii phng nng lng.Magi l mt cht dinh dng khc cng c nhiu trong go lc, c chng minh trong cc nghin cu l c tc dng gim tnh khc nghit ca bnh hen suyn, gim huyt p, gim s thng xuyn ca cc cn au na u, gim nguy c ca cc cn au tim v t qu [43].Nhiu nghin cu khoa hc gn y cho bit nhng thc phm c nhiu cht x, nh go lc v cc loi u khc c kh nng ngn nga bnh ung th rut khng phi v cht x m chnh l cht phytate cha trong cht x.2.2 Gii thiu v ln men lactic2.2.1. Cc chng vi sinh vt c s dng trong ln men lactic2.2.1.1 LactobacillusLactobacillus l tn mt ging vi khun, ging ny c nhiu loi nh Lactobacillus acidophilus, Lactobacillus sporogenes, Lactobacillus kefir...Trong ng rut lun c nhiu loi vi khun k sinh, trong c c nhng loi c ch v c hi cho sc khe con ngi. S tn ti ca vi khun lactic to thnh s cn bng vi khun trong ng rut. Vi khun Lactobacillus c the lm gim hi chng nhy cm ng rut.Cc vi khun ny c nhim v bin i cht x thc phm, thc n cha tiu ha ht rut non thnh acid lactic, acetic, butyric, hng lot vitamin, acid amin, men, hocmon v cc cht dinh dng quan trng khc. N cng sinh ra cc kh nh NH3, C02, H2S... u trnh bin i gi chung l qu trnh ln men, m nh n, thc n c tiu ha hon ton.Trong mi trng hot ng ca i trng, cc vi khun c ch c kh nng ln p, bp v tiu dit rt nhiu loi vi trng gy bnh.Ngoi glucose, Lactobacillus aciophius cn s dng aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, trehalose cho s ln men [2],Lactobacillus cng gip tiu ho ng lactose trong sa mt cch d dng hn. Loi vi khun c ch ny cng em li hiu qu cao cho nhng ngi b au bng tiu chy v lon khun ng rut do hu qu ca vic dng qu nhiu khng sinh khin cc vi khun c ch b tiu dit.Mt nghin cu gn y cho thy, vi khun Lactobacillus cn c tc dng cha bnh chm tr em. e phng nga ri lon ng rut, h vi sinh vt ng mt vai tr rt quan trng ng tiu ha, c bit l h tiu ha ca tr.Mt s chng Lactobacillus thng dng trong ln men lactic nh: Lactobacilliis bugarcus: ln men ng hnh, l trc khun trn i khi dng ht, thng kt thnh chui di, Gram (+), khng c kh nng di ng. Chng c kh nng ln men c cc loi ng glucose, lactose, galactose, khng ln men c sacaroza, xylose, arabinose, sorbose, dulcitol, mannitol, dextrin, inulin. Chng khng c kh nng to ra nitrit t nitrate. y l ging a nhit, nhit ti thch cho pht trin l 40 - 45c, ti thiu l 15 - 20c, to thnh acid mnh.

Hnh 4: Vi khun Lactobacillus bulgaricus [48].Lactobacillus casei: ln men lactic ng hnh, trc khun nh, Gram (+), thng gp dng chui di hoc ngn, tch t ti 1,5% acid. Chng khng c kh nng chuyn ng. C kh nng ln men c cc loi ng glucose, fructose, mannose, galactose, maltose, lactose, salicin. Trong qu trnh ln men chng to ra D acid lactic. Nhit ti thch cho pht trin l 38 - 40c, nh c hot tnh proteaza nn c th phn hu protein trong sa thnh acid amin.

Hnh 5: Vi khun Lactobacillus casei [48].Lactobacillus lycopersic. ln men lactic d hnh, l trc khun Gram (+), sinh hi, trong thin nhin chng tn ti thnh tng i mt, c kh nng to bo t. Trong qu trnh ln men ng, chng to ra con, acid lactic, acid acetic v C02. Ngy nay chng c coi nh cc bin chng ca Lactobacius brevis [3].Lactobacilluspasteurianus: l trc khun Gram (+), c kch thc rng: 0.5 - l.Oim, di: 7.0 - 35|im. Trong thin nhin chng tn ti ring l, khng di ng. Chng c kh nng ln men c arabinose, glucose, fructose, galactose, maltose, saccharose, rafinose, trehalose, manitol, dextrin. Trong qu trnh ln men chng to ra mt lot sn phm nh: CO2, alcohol, acid lactic, acid acetic, acid formic. Nhit thch hp t 29 - 33c.Lactobacillus bifidus: trc khun rt nh, thuc loi Gram (+). Chng khng c kh nng di dng, c kh nng ln men c cc loi ng glucose, fructose, galactose, saccharose, inulin, dextrin. Nhit pht trin tt nht ca vi khun ny l 37c.Lactobacillus causaciccus: trc khuan Gram (+) ngn, khng c kh nng chuyn ng, c kh nng ln men cc loi ng glucose, fructose, mannose, galactose, maltose, lactose, mannitol. Nhit pht trin ti u l 48 - 50c.Lactobacillus delbnicki: trc khun di Gram (+), c kch thc rng: 0.5im 0.8|im, di: 2.0 - 9.0|im, khng di ng. Chng c kh nng ln men cc loi ng glucose, maltose, fructose, galactose v dextrin, chng khng c kh nng ln men xylose, arabinose, rhamnose, lactose, raffinose, trehalose, inulin.Lactobacillus brevis: ln men lactic d hnh, l loi trc khun Gram (+), khng c kh nng di ng, c kch thc rng: 0.7 - 1.0|j,m, di: 2.0 - 4.0|im, tm thy ch yu trong mui chua bp ci, rau ci, da chut, v vy n cn c gi l trc khun bp ci. Trong thin nhin chng thng lin kt vi nhau thnh chui. Trong qu trnh pht trin chng c th s dng lactate canxi nh ngiin cung cp carbon. Chng c kh nng ln men cc loi ng arbinose, xylose, gluxose, fructose, galactose, maltose. Trong ln men ngoi acid lactic (1,2%), n cn to thnh acid acetic, ru etylic (2,4%), C02, n cn to hng lm cho sn phm c hng v d chu. Nhit pht trin ti a l 30c, vi khun ny c nhiu trong sa, kefia, da chua...

Hnh 6: Vi khun Lactobacillus brevis [47].Lactobacillus eichmannii: trc khun Gram (+). Trong t nhin chng c kh nng to thnh chui ngn, kch thc t bo t 0.6 - 2.0|j,m. Chng c kh nng ln men glucose, fructose, maltose, saccharose, trehalose v khng c kh nng ln men lactose, galactose, raffinose, arabinose, rhamnose, dextrin, inulin. Trong qu trnh ln men, chng to ra L - acid lactic, khng c kh nng to nitrit t nitrat. Nhit pht trin ti u l 36c.Lactobacillus helveticcus: trc khun, c kch thc rng: 0.7 - 0.9|im, di: 2.0 - 6.0|im. Trong thin nhin chng c th tn ti ring l tng t bo, cng c th to thnh chui t bo. Chng c kh nng ln men cc loi ng glucose, fructose, galactose, mannose, maltose, lactose. Nhit pht trin t 40 - 42c. Vi khun ny c s dng nhiu trong sn xut sa chua v phomai cng.Lactobacillus thermophus: l trc khun gram (+), kch thc t bo 0.5 - 3.0|j,m, khng c kh nng di ng. Nhit pht trin ti u l 30c, c th chu c nhit 65 - 75c. Vi khun ny c s dng nhiu trong sn xut sa chua v phomai.Lactobacillus pantarum: trc khun gram (+), kch thc t bo rng: 0.7 - 1 im, di: 3 - 8|im. Nhit pht trin ti un l 30c, c kh nng chu c nng NaCl 5,5%. Vi khun ny c dng nhiu trong ch bin sa [4].

Hnh 7: Vi khun Lactobacius pantarum [47].* ng dung ca vi khun LactobacillusVi khun lactic ngy cng c s dng nhiu trong cng ngh thc phm, trong y hc v trong nng nghip. Nhng hng ng dng c bn gm: ng dng ca Lactobacilus trong cng ngh thc phm ng dng sn xut da chua: Mui chua rau qu chnh l qu trnh hot ng sng ca vi khun lactic v vi khun acetic. Qu trnh pht trin ca chng trong rau qu, khi ln men s to ra acid lactic v acid acetic cng mt s loi acid hu c khc. Cc acid hu c ny lm pH ca dch chng li hin tng gy thi rau qu. Mt khc, nh' c lng acid hu c c to thnh s lm tng hng v ca khi rau qu. Chnh v th, ngi ta cho rng mui chua rau qu l qu trnh va mang ngha ch bin, va mang ngha bo qun.Sn xut tng: Sn xut tng theo phng php ca ngi min Bc (Vit Nam) c giai on ng nc u sau khi rang. Qu trnh ng nc u xy ra nhiu phn ng sinh ha khc nhau trong c qu trnh ln men lactic to pH thch hp cho sn phm v lm tng hng v cho sn phm.Sn xut cc sn phm ln men t sa: Trong sn xut cc loi sa chua u c s dng ln men lactic. Nh c qu trnh chuyn ha ng thnh acid lactic m casein c kt ta v to cho sn phm c hng v c trung. thc n gia sc: v nguyn tc, cc loi c v l cy lm thc phm gia sc cng ging nh cng ngh sn xut da chua. Qu trnh ln men lactic xy ra lm tng gi tr dinh dng v kh nng t bo qun c, l cy cho gia sc.ng dng ca Lactobacilus trong y hcng dng vi khun lactic cha bnh ng rut: Vic ng dng ny c Vit Nam ng dng t lu. Khi ngi ta b tiu chy, bc s khuyn hng ngy ung 1 - 2 chn nc da chua, phng php ny t ra rt hiu nghim trong iu kin ngnh dc cha pht trin. Da vo hiu qu s dng vi khun lactic trong vic cha tr tiu chy, Php sn xut v a ra th trng t hng chc nm nay 1 sn phm mang tn Biolactyl, sn phm chuyn tr tiu chy t nhiu vi khun lactic.ng dng vi khun lactic theo php cha vi lng ng cn: Trong qu trnh vn ng ca c th, m c hot ng mnh v trong 1 thi gian di s gy ra hin tng mt mi. Hin tng mt mi ny xut hin do cc phn ng sinh ha xy ra trong m c, to ra acid lactic. Cc bc s to ra mt v thuc bao gm acid lactic kt hp vi cy kim sa c kh nng gip c th khng cn mt mi, c kh nng lm vic v hot ng lin tc trong thi gian di.ng dng vi khun lactic trong phu thut chnh hnh: Ngi ta thng s dng loi vt liu c tn l Purasorb. Purasorb l 1 hp cht cao phn t c sn xut t acid lactic. Thnh phn ca Purasorb bao gm lactides, glycolide, polylactides, polyglycolides, lactide/glycolide copolymer. Purasorb c s dng nh nhng inh ghim, gn phn xng li vi nhau, khi xng nh hnh Purasorb s t tiu hy.Sn xut vt liu sinh hc: Cc nh khoa hc ang nghin cu to ra nhng vt liu sinh hc dng trong y hc bng cc copolymer ca acid lactic. Cc copolymer ny c tnh nng rt ging nhng b khung xng ng vt, hng nyang c nghin cn v ngi ta hy vng trong tng lai n s c ng dng nhiu.Sn xut cc loi sa v bt giu canxi: Ngi ta bo sung lactate canxi vo thnh phn sa bt dinh dng, bnh ngt, bnh nng tng lng canxi cho cLm cht do trong tng lai: Cc phng th nghim ang nghin cu loi cht do mi thay th cho cht do c kh phn hy. Cht do mi ny l loi polyme c gi l poly acid lactic (PLA). l sn phm c to ra t' phn ng trng hp acid lactic. Ngi ta hy vng trong tng lai n s thay th cht dco c sn xut t du m v tnh cht d phn hy ca n c ngha rt ln trong bo v mi trng. Trong cng nghip nh, acid lactic l dung mi cho cng nghip sn xut sn, vecni, nhum v thuc da.Trong m phm: Cc loi lactate kim loi c s dng trong thnh phn ca mt s m phm chm sc da nh Punosal. M phm ny c cht chng li cc vi sinh vt c trn b mt da, lm m v sng da.Ko cao su c cha cc chng vi khun c li Lactobacillus do Cng ty ha chat BASF ca c pht trin. y l loi sn phm gip ngi dng loi tr cc loi vi khun gy bnh rng ming. Marcinowski cho bit, ko cao su c th nghim trn rt nhiu ngi v chng minh c kh nng gim ng k cc vi khun c hi. Ko cao su cha mt chng Lactobacillus c bit, vi khun ny c trong sa chua v sa. BASF khm ph ra mt nhm vi khun Strepptococcus mu tans, l vi khun gy ra su rng. Strepptococcus mutans bm vo rng to ra acid n mn lm hng men rng.Hnh 8: Vi khun Streptococcus mutans [44],

Chng Lactobacillus mi tn l Lactobacillus anticaries, lm cho s. mutans kt thnh khi khng th dnh ln b mt rng v b loi b d dng khi sc ming. Cc th nghim cho thy ko cao su c th gim lng vi khun c li trong ming khong 50 ln. Vi khun ny c bit t lu v rt an ton.ng dng khc ca vi khuan Lactobacillus l ngn nga mi m hi. Hai chng vi khun l Lactobacillus pesodoris v Lactobacillus aaodors c th p dng ngn nga vi khun gy mi chn v nch. BASF hy vng s sn xut mt cht kh mi da trn L. alaodoris. Chng vi khun ny ngn nga mi hi nch bng vic hn ch to ra acid 3 - metyl - 2 hexonic. Cho n nay, cc th nghim cho thy sn phm u tin cha L. alaodoris c th gim s hnh thnh mi ln ti 8

Hnh 9: Vi sinh vt thuc nhm Lactobacilhis [44],2.2.1.2 LeuconostocLeuconostoc gm nhng lin cu khun ln men lactic ng dng, ln men ng sinh acid lactic v 1 lng ln acid acetic, cn etylic v kh C02. Kh nng ca 2 loi Leuconostoc dextrancium v Lenconostoc citrovontm ln 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.Mt s c trung ca ging Leucunostoc cho n v tr quan trng trong thc phm nh: Sn sinh diacetyl, s chu ng ca nhng nng mui cao lm cho Leuconostoc mesenteriodes c em dng giai on u ca s ln men lactic. S chu ng c nhng nng ng cao n 55 - 60% (i vi Leucnstoc

Hnh 10: Vi sinh vt thuc nhm Leuconostoc [45].mesenterudes) lm cho vi khun c th pht trin trong xiro bn lng v kem ... sn sinh ra nhiu thn kh t ng lm h hng 1 s loi phomai, xiro.

2.2.1.3 StreptococcusStreptococcus l cu khun hoc trc khun rt ngn, ch yu ln men lactic ng hnh, kt song i hoc thnh chui ngn. Ging a m, nhit pht trin ti thiu l 10c, ti a l 40 - 45c v pht trin tt 30 - 35c. Trong mi trng n tch t c 0.8 - 1% acid. Mt s chng to thnh bacteriocin.Mt s dng Streptococcus thng dng ln men lactic nh:Streptcoccusactis: l lin cu khun Gram (+). Nhit pht trin t 10 -45c,c th chu c nng NaCl 4%. Khi lnmen ngglucose, maltose,lactose, xylose, arabinose, saccharose, trehalose, monnitol to ra acid lactic, C2, acid acetic, diacetyl. Chng c kh nng ln men c raffinose, inulin, glycerol, sorbitol. Chng c s dng rng ri trong ch bin cc sn phm nh sa chua, cream - b chua, phomai. Streptococus lactic c kh nng ln men 30c i vi sa, ng glucose, mantose, lactose, galactose.Streptococcuscremoris: l t bo hnh cu vkt thnh chui di, a m vto tacid trong mitrng. Nhit thch hp chopht trin l25c, ti thiu l10c, ti a l 36 - 38c.

Streptococcus thermophius: c dng hnh cu, kt thnh chui di, pht trin tt nhit 40 - 45c, tch t khong 1% acid. Thng dng phi hp vi trc khun lactic ch bin sa chua v cc loi c bit, sa chua nu chn v phomai.Streptococcus /alcalis: l t bo Gram (+), chng thng to thnh chui t bo hnh cu, c kh nng chu c nng NaCl 5%, c kh nng ln men ng glucose, maltose, lactose, trehalose, silicin, sorbitol [3],Gn y, ngi ta nghin cu sn xut phomai t sa da di tc dng ca vi khun Streptococcus dacetylactis. Ging c bo qun trong mi trng sa v gi trong t ng. Nhit nui cy sinh trng v ln men mnh nht khi nui cy 28c, pht trin kh 35c v thp nht 20c. Sau nhiu th nghim cho thy mi trng tt nht l mi trng sa bt gy b sung glucose v nc chit nm men.Streptococcus diacetylactis cn c gi l Pneumococci, l cu khun Gram (+), xp tng i hay thnh chui, c v bng polysaccharidc. Pneumococci d b ly gii bi nhng cht hot ng b mt nh mui mt. Thng tr ng h hp trn ca ngi v c th gy vim phi, vim xoang, vim ph qun, nhim khun mu, vim mng no,... Hnh dng: th in hnh xp tng i, hnh ngn gio, Gram(+). bnh phm m hay m, vi khun ng ring l hay xp thnh chui. Khi tr nn gi th bin thnh Gram (-) v d t ly gii.

Hnh 11: Vi khun thuc nhm Streptococcus [46].

2.2.2. c im chung ca Lactobacillus acidophilus v ln men lactic 2.2.2.1 c im ca Lactobacillus acidophilusLactobacillus acidophilus thuc:Gii: BacteriaNgnh: FermicutesLp: BacilliB: LactobacililalesH: LactobacaceaeGing: LactobacillusTn vi sinh vt: Lactobacillus acidophilusLactobacillus acidophilus', l trc khuan ln men lactic ng hnh, chu nhit, nhit ti thch cho sinh trng l 37 - 40c, ti thiu l 20c. Trc khun ny c phn lp t rut tr em v b mi . Mt s chng c kh nng to thnh mng nhy. Trong thin nhin chng tn ti ring l, i khi chng to thnh nhng chui ngn, c kh nng chuyn ng. Chng c kh nng ln men 1 s loi ng glucose, fructose, galactose, mannose, maltose, lactose, saccharose to ra acid lactic. Chng hon ton khng c kh nng ln men xylose, arabinose, rahamnose, glycerol, sorbitol, dulcitol, inositol. Trong qu trnh ln men chng to ra c 2 dng ng phn quang hc ca acid lactic. Lactobacillus acidophilus c kh nng sng 2 ngy trong dch v, 5 ngy trong dch mt tinh khit, 8 ngy trong dch trng.Lactobacillus acidophilus c coi l loi Probiotic thng dng nht, hay l loi vi khun c ch. Loi vi khun c li ny c tr ti rut, m o bo v chng li s xm nhp hay gia tng ca cc sinh vt c hi c th gy bnh. S phn r ca thc n do khun L. acidophius sn xut ra acid lactic, hydrogen peroxide... to ra s phn ng ca mi trng chng li cc sinh vt khng a thch.L. acidophilus cng sn xut ra lactase, loi enzyme c kh nng ph hu ng sa (lactose) thnh cc loi ng n gin.Lactobacillus acidophilus sn xut acid lactic v cc cht dit khun bacteriocin nh lactocidin, ngn cn s xm nhp v c ch s tng sinh ca cc vi khun gy bnh trong thc phm nh Escherichia coli, Salmonella v mt s vi khun lactic khc, gip cho c th khng vi nhim khun ng rut.Lactobacius acidophius ng vai tr sinh l quan trng nh tng hp cc vitamin, c kh nng bn vng vi 40 loi khng sinh [3].2222 Ln men lactcLn men lactic l qu trnh chuyn ho ng thnh acid lactic nh vi sinh vt, in hnh l vi khun lactic. Ln men lactic l 1 trong nhng loi hnh ln men pht trin nht trong thin nhin.Ln men lactic l 1 qu trnh trao i nng lng. Cc phn t ATP c hnh thnh trong qu trnh chuyn ho c cht (lactose) s c vi khun gi li trong t bo phc v cho qu trnh trao i cht v sinh trng ca vi sinh vt. Ngc li cc sn phm nh acid lactic, ethanol, C02 c vi khun thi vo mi trng ln men. Ket qu l hm lng acid lactic tch lu trong mi trng ln men ngy cng tng, lm gim pH mi trng v ko theo nhng bin i l ho khc.Trong qu trnh ln men lactic, ngoi sn phm l acid lactic, acid acetic, ethanol, C02 trong dch ln men cn xut hin c trm hp cht ho hc mi khc. Chng l sn phm trung gian hoc sn phm ph ca qu trnh ln men. Hm lng ca chng trong dch ln men thng rt thp (vi ppm hoc t hn). Mt s hp cht trong nhm trn rt d bay hi. Chng ng vai tr quan trng trong vic gp phn hnh thnh nn mi v c trng cho nhng sn phm ln men lactic.Khi nng ca acid lactic t 2 - 3% s c ch hot ng ca cc vi sinh vt khc, k c E.coi. Chnh v th nn ln men lactic c ng dng sn xut nhiu sn phm khc nhau nh: sa chua, b, phomai, da chua...Phng trnh tm tt ca qu trnh ln men lactic:C6Hi206 -> 2C3H603+ 136 Kj (32,4 Kcal).Ln men lactic gm c ln men ng hnh v ln men d hnhLn men ng hnh: Lng acid lactic to thnh chim hn 90%, ch 1 lng nh pyruvat b kh carbon chuyn thnh acid acetic, ethanol, C2 v acetoin. Lng sn phm ph to ra ph thuc s c mt ca oxy.Cc chng vi sinh vt c s dng trong ln men ng hnh nh: Lactobaternm case, Lactobacterium cremoris, Lactobacterium bulgaricus,Lactobacterum debruckii... Phng trnh tng qut trong qu trnh ln men ng hnh:C6H1206+ 2ADP + 2Pi -> 2CH3CHOHCOOH + 2ATPTrong mt s trng hp, ln men ng hnh c th c chuyn sang dng d hnh khi iu kin ln men thay i.Ln men d hnh: Ch c 50% lng ng to thnh acid lactic, ngoi ra cn c cc sn phm ph khc nhau nh acid acetic, ethanol, CO2, cc sn phm ph tng tc vi nhau to thnh ester c mi thm. Phng trnh tng qut trong qu trnh ln men d hnh:c6hI2o6 -> CH3CHOHCOOH + CH3COOH + C2H5OHLng sn phm ph to thnh hon ton ph thuc vo ging vi sinh vt, mi trng dinh dng v iu kin ngoi cnh. Acid lactic thng chim 40% lng ng c phn hu, acid suecinic 20%, ru etylic 10%, acid acetic 10% v cc loi kh gn 20%2.2.2.3 c im chung ca cc chng vi sinh vt ln men lacticVi khun lactic thuc h Lactobaciliaceae. Acid lactic c pht hin vo nm 1780 nh nh ha hc Sheele ngi Thy in, sa chua, acid lactic c tha nhn l sn phm ca qu trnh ln men vo nm 1847 [5].Vi khun lactic thuc vi khun Gram (+), khng di ng, khng c kh nng to bo t (tuy nhin hin nay ngi ta tm thy mt s ging thuc h vi khun lactic c kh nng to bo t).Vi khun lactic thuc vi khun hiu kh ty tin, khng cha cytochrom v enzyme catalase, c kh nng sinh tng hp enzyme peroxydase rt mnh. Chng phn gii H2O2 e to ra H20 v 02 pht trin.Theo kha phn loi ca Bergay, h Lactobaciaceae chia lm 2 h: Streptococeae v Lactobacieae.Streptucoceae li chia ra Streptococcus v Leuconostc.Lactobacileae chi c 1 loi l LactobacillusVi khun lactic c nhiu trong thin nhin. Chng tn ti nhiu c, nht l c kh, trong c th ngi v ng vt, trong ming, rut. Mt s loi trong h vi khun lactic nh Streptococcus c kh nng gy bnh. Nhm vi khun lactic rt a dng gm nhiu ging rt khc nhau, t bo ca chng c th l hnh cu, hnh que, phn bit chng v kh nng ln men ng hnh hay d hnh. Kh nng tng hp nhiu hp cht cn cho s sng ca nhng vi khun ny rt yu [4].Cc loi vi khun lactic khc nhau to thnh acid lactic trong mi trng v nh vy sc chu acid cng khc nhau. a s cc trc khun lactic ng hnh to thnh acid cao hn (khong 2 - 3,5%), lin cu khun (khong 1%). Cc trc khun ny c th pht trin pH: 3.8 - 4, cu khun khng th pht trin mi trng ny. Hot lc ln men tt nht vng pH: 5.5 - 6.0.a s vi khun lactic, c bit l trc khun ng hnh rt kn chn thnh phn dinh dng trong mi trng v ch pht trin c trong mi trng c tng i y cc acid amin hoc cc hp cht nito phc tp. Ngoi ra chng cn nhu cu v vitamin (Bl, B2, B6, PP), cc acid pantotenic v folic. Bi vy, mi trng nui vi khun lactic c thnh phn kh phc tp [5].Vi khun lactic chu c trng thi kh hn, bn vng vi C02 v cn etylic, nhiu loi vn sng c trong mi trng c 10 - 15% cn hoc cao hn, mt s trc khun bn vi NaCl (ti 7 - 10%).Cc vi khun lactic un m c nhit sinh trng ti thch l 25 - 35c, cc loi a nhit c nhit ti thch l 40 - 45c, a lnh pht trin nhit tng i thp (5 c hoc thp hon). Khi gia nhit ti 60 - 80c hu ht chng b cht sau 10-30 pht. S pht trin ca n cn c s c mt ca peptone, acid amin hay mui amn. Chng c yu cu c bit v cht dinh dng l giu vitamin, acid amin v khong cht. Qu trnh ln men xy ra tt nht trong mi trng acid pH t 5.5 - 6, khi pH nh hn 5.5 qu trnh ln men b dng li.Vi khun lactic c hot tnh proteaza: phn hy c protein ca sa thnh cc peptid v acid amin. Hot tnh ny cc loi l khc nhau, thng l trc khun cao hn. Vi khuan lactic ln men c a s disacarit.Chng c kh nng ln men nhiu loi ng on v ng i nhng khng c kh nng ln men cc loi gluci phc tp v tinh bt, ch c loi L. delbmeckii l ng ha c tinh bt. Mt s vi khun ln men lactic d hnh s dng c pen toza v acid citric.Mt s loi c kh nng to thnh mng nhy. Mt s khc c kh nng i khng vi th hoi sinh v cc vi sinh vt gy bnh hoc lm thi ra thc phm. Nh vy, ngoi kh nng to thnh acid lactic, cc loi ny cn sinh ra cc hp cht c hot tnh khng sinh (ngi ta gi cc hp cht ny l bacteriocin). Nhng cht khng sinh ny khng dng trong y hc m ch c dng trong bo qun thc phm c hiu qu kh quan. Cc vi khun lactic ngoi vic to thnh acid cn c 1 s loi to c cht thm (diacetyl, acetoin, acid bay hi...) nh Streptococcus diacety lactic.Vi khun Lactobacillus c th lm gim hi chng nhy cm ng rut. Cc vi khun ny c nhim v bin i cht x thc phm, thc n cha tiu ha ht rut non thnh acid lactic, acetic, butyric, hng lot vitamin, acid amin, men, hocmon v cc chat dinh dng quan trng khc, sinh ra cc kh nh NH3, CO2, H2S...2.2.2A ng dng ca Lactobacillus acidophilusLactobacillus acidophilus cn l loi Probiotic thng dng nht, hay l loi vi khun c ch. Loi vi khun c li ny c tr ti rut, m o bo v, chng li s xm nhp hay gia tng ca cc vi sinh vt c hi c th gy bnh. y l c ch hot ng hon ho.V d, s phn r ca thc n do khun L. acidophilus sn xut ra acid lactic, hydrogen peroxide... to ra s phn ng ca mi trng chng li cc sinh vt khng a thch.L. acidophilus cng sn xut ra lactase, loi enzyme c kh nng ph hu ng sa (lactose) thnh cc loi ng n gin.

Hnh 12: Vi khun Lactobacillus acidophilus [48].

2.2.3. Cc sn phm ln men lacticTrong t nhin c rt nhiu sn phm c ln men lactic nh: ung Boza: Boza l ung thng dng Anbani, Bulgari, Serbia, Montenegro, Macedonia, Th Nh K. Thc ung ny c lm t bt bp, la m v go, l cht lng c nht cao, cha acid lactic v cn khong di 1% c to ra trong qu trnh ln men. Boza c mu vng nht, v chua ngt ty theo cc nc khc nhau [23].Bt bp, bt m, bt go c phi trn tng ng vi t l (2 : 1 : 1) > nu si hn hp vi 5 ln nc trong 1 gi, khuy lin tc > lm mt v nhit phng qua cm cht st c pha long vi t l 2,5 : 1, thm 20% ng v trn k > cy 2% chng t Boza mua thnh phm ch > v trng bnh tam gic 1 lt cha 500ml hn hp cy chng nui 30c. Qu trnh ln men c theo di trong vng 40 gi.Thc ung Amazake: l loi ru ca Nht Bn c ln men t go m ch yu l go lc. Amazake s dng Lactobacillus lm vi sinh vt ln men. Sn phm c tinh bt, oligosarccharide, lactose, sa nguyn kem [16].Vt liu v phng php: Chng ti trnh by th ung tng t Amazake ca tc gi Yuij ODA v cc cng s.Go (16g) ngm trong 24 gi > cho thm nc ct trong 30 pht > nu chn 105c trong 20 pht > lm lnh, thm dung dch nui cy LactobaciUus amyovorus vo > ng ha 55()c trong 24 gi pH = 4.2 > sn phmMi trng nui Lactobacilus amylovorus gm: 2% sa khng kem, 0,1% cao men (pH = 6,8), 1% glucose, sucrose, tinh bt hoc bp kh, nc lOOml. Kh trng 105c trong 30 pht (nu dng bp th kh trng 150c trong 4 gi).Kho st s tc ng ca nguyn liu v iu kin ln menT kt qu kho st tc ng ca nhit ln pH, nng acid lactic v nng ng ha tan trong dch thu c cho thy s ng ha 37c v 45c trong 24 gi, vi khun lactic to acid lactic mt cch c hiu qu t ng (thy phn t tinh bt ca go nu chn). Hu qu l dch cha nng cao acid lactic lm xu i gi tr cm quan v v chua qu mnh khng th chp nhn. Ngc li dch ng ha 60c, khng cn v chua cho s ln men lactic acid b c ch bi nhit cao. iu kin tt nht l nhit t 55 c, pH = 4.2, hm lng acid lactic l l,89g/ml v Brix ca dung dch ng l 8,7 [16] . ung Sobia: l loi ung c ln men t bt malt v bt m. Sn phm Sobia c pH nm trong khong t 3.37 - 5.53, nng acid lactic t 0,1 - 0,3% [19].Vt liu v phng php: Bt Malt (150 - 200g) + bt m (150 - 200g) > thm nc (8-10 lt) trn > lc qua vi tha > thm ng (7 - 10%) > thm qu v bch u khu > trn * ln men nhit m (30 - 40C) trong 24 gi > sn phmKho st s tc ng ca nguyn liu v iu kin ln menKho st hm lng vi sinh vt hin din trong 14 mu Sobia cho thy: Tong s vi khun hiu kh t 4,17 - 8,09 log cfi/ml, trong khi vi khun lactic tm c t 4,01 - 8,19 log cfu/ml, Coi/orm t 0,67 - 3,84 log cfi/ml, nm men v mc chim t 3,06 - 6,29 log cfi/ml. Trong s 12 vi khun lactic c phn lp 86% l Lactobacilus spp. Gm 96 th phn lp v nhng loi vi khun khc vi t l xc nh. tt cc mu Sobia, pH u nm trong khong t 3,37 - 5,53. Nng acid lactic t 0,1 - 0,3%. Ket qu nghin cu cho thy s ln men Sobia chnh l s ln men acid lactic. ung Oat: Oat c ln men t yn mch. Vi sinh vt c s dng ln men l: Lactobacillus pantarum, Lactobacillus paracasei, Lactobacillus acidophilus [18].Vt liu: Yen mch mua t ch v c lm sch bn ngoi > xay bng my v lc qua ry. Tinh bt ca yn mch cng c xay 3 ln c tng s cht x trong bt l cao nht. ng c nghin nh mua t ch, inulin thu t Orafti, nng cht lng protein. Ging vi khuan: Lactobacillusplantarum, L. paracase, L. acdophus.Qui trnh: Trn 5% tinh bt, 4% ng, 0,2% inulin, 0,5% whey protein to thnh 1 hn hp ng nht un nng t' t (mi pht tng 1C) cho n si v cho si u trong 3 pht ph v tinh bt yn mch > em kh trng cht st va c nu 121 c trong 15 pht > lm lnh n 37c, khuy trn sut thi gian ny trnh s to mng b mt. ung Kunun Zaki c to theo phng php truyn thng [38, 39],Ht ng cc ra sch > ngm trong nc > xay t to dng paste >chia lm 2 phn > phn ln em nu si vi nc> phn nh cm nghin vi cc thnh phn khc

Trn li vi nhau> ln men qua m > lc > Kunun ZakiPhng php ci tin ca Gaffa.T.Ht la min ra sch > ngm vi nc m t l 1 : 2 nhit 60 - 70c v 0,5% sodium metabisulft ngm trong 3 gi > vt ra v ra k vi nc sch > nghin t cng vi cc thnh phn khc to dng paste > chia thnh 2 phn theo t l 1 : 3 cho nc m vo v nu si phn ln to dng gelatin (cht lng trong sut) > khi nhit h xung cn 60 - 70c, thm phn paste nh vo > khuy trn, s ha lng v ng ha xy ra trong 6 gi nhit 28 - 30c lc bng vi v trng > ng chai v thanh trng Paster 60c trong 30 pht > sn phm Kunun - Zaki.

ung Kunun Zaki c to theo phng php ci tin ca B.J.O Efliuvwevwere [29].Ht k (500g) > ngm vi 1 lt nc trong 24 gi 27c > gn nc v ra sch ht k, trn thm lOg gng kh > cho nc vo vi t l 1 : 2 > cht st c sng lc > lng t 3 - 5 gi > chia lm 2 phn > phn 1 nu vi nc (t l 1 : 2), lm ngui 45 - 50c > phn 2 khng nuTrn 2 phn theo t l 1 : 1

> ha thm 3 lt nc ln men trong 8 gi > thm 2% ng > sn phm Kunun - zaki.S dng ln men lactic sn xut sa chua: Sa chua c v yaourt l sn phm ln men lactic t sa b ti, sa bt hay sa ng vt ni chung sau khi kh cht bo v thanh trng vi khun gy bnh.Ngoi ra ln men lactic cn c s dng sn xut kefir, rau qu mui chua, nem chua...2.2.4. Gi tr ca cc sn phm ln men lactic vi sc khe con ngiCc sn phm ln men t vi sinh vt c vai tr quan trng trong nhiu lnh vc nh: thc phm, y hc, m phm... , cc sn phm ln men lactic chim mt v tr c bit. Cc thc phm to thnh do qu trnh ln men lactic rt phong ph nh: thc ung ln men t ng cc, phomai, sa chua, rau c, xc xch kh, chao tng...Thc ung ln men t ng cc Boza c chng minh l ngun nguyn liu di do cung cp cho vic sn xut Bacteriocin t vi khun lactic acid vi hot tnh chng vi trng gy h hng thc phm v vi khun gy bnh. ng thi vi s hin din ca acid lactic s gip ch cho vic tiu ha ca c the c d dng, lm p da v lm chm qu trnh lo ha [34],Oat l thc ung c ln men t yn mch, s dng cc ging vi sinh vt nh Lactobacillus plantarum, L. paracasei, L. acidophilus c coi nh l thc phm chc nng cung cp cng lc c Probiotic v Prcbiotic. Loi ung yn mch ny khng cha sa nh vn c th thay th sa v sa u nnh nht l rt ph hp vi sc khe ca ngi theo ch n chay.

Nhng ung ln men t ng cc c kh nng th ch nhng vi khun ng rut c li b khng sinh ph hu. H tr kh nng tiu ho v ngn chn cc vi khun gy bnh, iu tr s tng trng qu nhanh ca cc sinh vt c hi trong ng tiu ho, lm gim cc triu chng ri lon ng rut kch ng v c th c bnh vim ng rutSa chua l sn phm thu c khi ln men lactic sa ng vt, c nhiu ch li i vi sc kho mi ngi, l loi sn phm ph bin c nhiu ngi a thch v c cha cc cht dinh dng cn thit cho s pht trin ca c th con ngi. Sa chua tr thnh mn n c dinh dng cao, hp th ln, ngoi ra nh vi khun lactic, nn sa chua c tc dng cha bnh ng rut, bnh d dy v cc bnh v tiu ha ni chung. Sa chua c bit thch hp vi ngi gi, tr em, ngi mi m dy, nht l nhng ngi mc bnh v tiu ha.Nh qu trnh ln men lactic, mt phn protein trong sa phn gii thnh cc acid amin, cc cht ng bt chuyn ha thnh ng lactoza d tiu ha v cc cht thm nh acetoin, diacetin cng nhiu vi lng qu him c to thnh, kch thch s p ng min dch v lm gim cholesterol huyt thanh. Sa chua cn c nhiu cht b dng v d hp th vo mu. V vy m c th ngi c th hp th sa chua nhiu hn gp 3 ln sa ti, tt cho i tng ngi bnh trong giai on phc hi sc khe, suy nhc, bing n...Sa chua vn gi c v lm giu thm lng chat protein trong sa, c bit l chat casein, vitamin v cc loi khong cht cn thit, gip cn bng h vi khun, tng cng kh nng khng ca c th. Protein trong sa ngn nga ung th d dy, ng lactose lm tng vi khun bifidobacteria trong rut. Sa ln men s kch thch s tiu ha, lm cn bng mi trng ng rut. Vic s dng sa chua u n s phc hi tnh acid rut non, ng thi cng lm gim nguy c ung th ng rut. Calcium v st trong sa chua gip ngn chn bnh thiu mu hng call, vitamin A gip tng cng th gic, pepton v peptid c tc dng kch thch chc nng gan. Bn cnh , trong sa chua c cht khng sinh gi l lactocidine, c kh nng chng li cc virus gy bnh. Sa chua cn c xem nh mt loi m phm chm sc da hiu qu. Acid lactic trong sa chua vi tc dng ngn nga s xm nhp v kim ch hot ng ca cc loi vi khun c hi to nn mt mng chn an ton bo v cho da.Sn phm kefir cha nhiu cht chng oxy ha, khng th, cc cht chuyn ha v l ngun thc phm giu vitamin, cht khong c gi tr. Nhiu nghin cu cho thy qu trnh ln men sa t nhng ht kefir sng s lm tng gi tr dinh dng ng k nh vitamin B, acid folic, vitamin tan trong chat bo nh A, D, E, K. Kefir kch thch qu trnh tiu ha v s thm n, lm gim hm lng cholesterol trong mu, tng sc khng ca c th i vi cc yell t bt li ca mi trng nh chng cm lnh v cc bnh hay ly khc.Li ch ca rau ci mui chua: Nghin cu mi y nht ch ra rng n cc loi rau h ci nh ci bp v da bp ci c th gip gim nguy c mt s loi ling th, trong c ung th v. n bp ci v mn da bp ci c khi cn tr s gip ngn nga hu hiu bnh ung th v. n nhiu cc thc phm chng ung th nh bp ci v da bp ci Sauerkraut cng c tc dng h tr nga ung th nhng ph n ln tui.e ti: Th nghim to thc ung ln men lactic t- go lc

Da chua c tc dng kch thch tiu ho nh c men lactic, n ngon ming hon, tt hn cho c th. Ngoi ra cn c phng php bo qun c ti c b sung vi khun lactic lm thay i khu h vi sinh vt theo chiu hng c li, trong vi khun lactic chim u th, lm gim ng k cc loi vi sinh vt c hi cho qu trnh bo qun, do lm tng gi tr dinh dng ca thc n ln.


e ti: Th nghim to thc ung ln men lactic t- go lcCHNG 3. VT LIU V PHNG PHP NGHIN cu3.1 Vt liu3.1.1 Go lcGo lc c s dng l go lc , tt c go lc dng trong sut thi gian nghin cu c mua cng mt thi im v bo qun iu kin ni kh ro.3.1.2 Ging vi sinh vtGing vi sinh vt Lactobacilus acduphius c phng th nghim ca trng i hc Bch Khoa TP.HCM cung cp dng ng kh.Ging c nui cy trn mi trng MRS ca n sn xut v c chuyn qua mi trng trung gian l sa c.3.2 Ha cht, trang thit b v dng c3.2.1 Thit bT sy, t cy, t , ni hp kh trng3.2.2 Dng cBep in, ng nghim c y bng nt bng khng thm, gi ng ng nghim, pipet, erlen 150ml v 250ml, bercher, a Petri, a khuy, que cy, que trang, n cn, knh hin vi, cn in t, ng ong...3.2.3 Ha chte ti: Th nghim to thc ung ln men lactic t- go lc

Mi trng MRS c sn xut n , mi trng PCR, ng glucose, thuc nhum crytal violet, iodine, ichsin, cht ch th phenolphtalein, NaOH 0,1NGVHD: TS. NGUYN THY HNG#SVTH: NGUYN TH QUNH LY


3.2 Phng php nghin cu3.2.1 S ni dung nghin cuKho st LactobacillusKho st nguyn liu

acidophilusgo lc

T l go : ncKho st cc iu kin ln menT l ng b sung

T l gingHng liuTo sn phmTheo di thi gian bo qunnh gi cht lng sn phmS 2: B tr ni dung nghin cu3.2.2 B tr ni dung th nghim3.2.2.1 Kho st Lactobacillus acidophilusGing Lactobacillus acidophilus c tng sinh trn mi trng MRS Mi trng MRS dng e gi ging v tng sinh ging.Ging c cy vo mi trng c v mi trng lng trong ng nghim iu kin v trng.Cy ging ng kh vo erlen cha mi trng MRS lng, lc u.Tt c mi trng c cy ging em vo t 37c trong 24 - 48 gi nhm tng sinh ging.Kho st vi th: Xc nh Gram bng phng php nhum Gram.

Phng php nhum Gram do nh vi khun hc an Mch Hans Christan Gram (1853 - 1938) pht minh ra t nm 1884. Nh phng php ny ngi ta phn bit ra 2 nhm vi khun l: Vi khun Gram dng v vi khun Gram m. Nhum Gram khng nhng gip phn bit c vi khun nh cc c im hnh thi v s sp xp ca t bo m cn cung cp thng tin v lp v t bo. Khi nhum theo phng php ny, t bo vi khun Gram (+) c lp v t bo dy to bi peptidoglycan s c mu tm, cn vi khun Gram (-) c lp v t bo mng hn do c t peptidoglycan hn v c bao bc bi mt mng mng s c mu hng [6].Cho 1 t ging vi sinh vt trn lame.Cho crytal violet ln, b sung thm 1 git iodine gip crytal violet bm cht vo mng t bo vi sinh vt trong khong 30 giy.Ra nc > Ra cn > Ra li bng nc > Cho thm 1 git basic fchsin > Ra nc > kh tm lame > Nh 1 git du soi knh > Quan st di knh hin vi vt knh 100Cy chuyn ging Lactobacillus acidophilus sang mi trng trung gian saSau khi tng sinh ging trn mi trng MRS, chuyn ging sang mi trng trung gian sa c trong 10-12 gi.Dng phng php m s khun lc kim tra s pht trin ca Lactobacius acdophius trn mi trng sa [6].3.2.22 Kho st nguyn liu go lca. Quy trnh to sn phm ln men

Ngm nc trong 24 giGn ncNghinNu chn vi nc, khuy uXay nhuynLc bng vi v trng

Hp thanh trngLm ngui 37c

Ln menHng liu v mu thc phmPhi trn

S 3: Qui trnh to sn phmb. Gii thch quy trnhRa: nhm loi b cc cht bn bcn ngoi ht go v cc ht khng t tiuchun.Ngm: Ngm go trong 24 gi, ngm go vi mc ch lm mm ht go. ng thi trong qu trnh ngm go, cc enzym ng trong ht go trng thi ny c kch thch hot ng v cung cp ti a cc cht dinh dng, thy phn mt phn tinh bt, protein go v ph v phn v la mu hng bn ngoi.Xay: Go c xay vi khong 200 - 400ml nc ph v t bo v gii phng cc ht tinh bt. Khi xay xong ta thu c mt hn hp nc v bt go mn.Nu: Hn hp c nu vi t l go : nc l 1: 10. Trong qu trnh nu phi khuy u trnh hin tng vn cc v bt go lc b lng di y ni. Dch go c nu trong khong 25 - 30 pht bt go chn nh. Nu xong ta thu c dch go lc chn st, mu hng, trong, lm tng gi tr cm quan [7].Xay nhuyn: Xay nhuyn hn hp nhm ng ha nc v go, b sung thm 1 lng nh nc b hao ht khi nu.Lc bng vi v trng: Lc c tc dng loi b nhng v la nh mm v chn cn st li. Lc c hn hp mn, p, ng nht, to gi tr cm quan cho sn phm.Phi trn: Trong qu trnh phi trn b sung thm ng cung cp thm c cht, ng thi to v ngt cho sn phm [8].Thanh trng dch go trc khi ln men: nhm tiu dit vi sinh vt c trong dch go trc khi ln men.Sau khi ngui dch go ta thc hin cy ging vo dch trong iu kin vtrng.Phi trn: Hng liu b sung l hng du, cam, hngsavi nng 0,1- 0,15% to mi thm cho sn phm, sau cho thmmu du tomuhngt nhin cho sn phm.3.2.2.3 Kho st iu kin ln menTrong qu trnh ln men, da trn cc ch tiu pH, lng acid lactic, lng ng ha tan. Chng ti kho st cc iu kin ln men sau:Hm lng nc b sung vo dch go.Hm lng ng b sung vo dch go.T l ging vi sinh vt cy vo dch go.Cc nh hng c kho st bng cch cho 1 yu t thay i trong khong gii hn cn cc yu t khc gi nguyn.a. Hm lng nc b sung vo dch goT l nc v go thay i: 1/8; 1/10; 1/12; 1/14; 1/16.T l ng v dch go lc: 12g/100mlDch go c thanh trng 90 - 95c trong 30 phte ngui nhit phngCy ging Lactobacilus acidophilus 5% vo dch go lc.Ln men trong 24 gi, 37c, pH: 5b. Hm lng ng b sung vo dch goT l ng v dch go thay i trong khong: 10/100; 12/100; 14/100; 16/100 (g/ml)T l nc v go l: 1/10.Dch go c thanh trng 90 - 95c trong 30 pht ngui nhit phngCy ging Lactobacilus acidophius 5% vo dch go lc.Ln men trong 24 gi, 37c, pH: 5c. T l giong v sinh vtT l nc v go l: 1/10T l ng v dch go lc: 12g/100mlDch go c thanh trng 90 - 95c trong 30 pht ngui nhit phngCy ging Lactobacus acidophius vo dch go lc vi t l thay i: 1%; 2%; 3%; 4%; 5%.Ln men trong 24 gi, 37c, pH: 53.2.2.4 Kho st hng liu b sungCc hng liu kho st nh: hng du, hng cam.Chn mu ph hp vi mu hng ca go lc.B sung thm hng sa nhm hng ti cc sn phm Probiotic lm t sa trn th trng.2)22.5 nh gi cht lng sn phmCht lng sn phm c nh gi qua cc ch tiu pH, Brix, hm lng acid lactic.nh gi cm quan cho php gii quyt nhng bn tm ca nh sn xut trong qu trnh kim tra nguyn liu, qu trnh sn xut, nh gi nh hng ca cc yu t cng ngh v k thut n sn phm cui cng, xc nh thi hn ca sn phm v cui cng l pht trin sn phm mi [9],Cht lng thc phm c cu thnh bi nhng tnh cht c trng v th hiu ca ngi tiu dng. Cc phng php phn tch cht lng cho php tip cn hai kha cnh ca cht lng thc phm thng qua vic phn tch cc thuc tnh v nh gi th hiu ngi s dng. Thc t nghin cu th hiu ngi tiu dng cho thy mc a thch chung ca ngi tiu dng ch t l thun vi mt s tnh cht ca sn phm.Chng ti nh gi cht lng cm quan sn phm qua 2 phng php l php th cho im th hiu v php th cho im cht lng.3.2.3 Cc phng php phn tcho pH: S dng my o pHo Brix: Dng my o Brix (khc x k) c thang o t 0 - 32Xc nh chua ca go nguyn liu [12].Nguyn tc: Dng 1 dung dch kim chun NaOH 0,1N trung ha ht lng acid t- do c trong mu vi cht ch th mu l phenolphtalein. chua c biu th bng th tch NaOH IN trung ha ht lOOg mu th.Tin hnh: Cn chnh xc lOg go, nghin nt, lc vi 80ml nc ct trong 1 gi, thm nc cho lOOml. e lng, ly 50ml nc trong trn nh lng.Cch tnh:n 100100nX20 X X =1050ppXc nh hm lng acid lacticNguyn tc: Dng dung dch kim chun NaOH trung ha lng acid lactic c trong mu vi phenolphtalein 1% lm cht ch th.Tin hnh: Cho lOml dch ln men vo erlen, b sung thm 20ml nc ct trung tnh, cho thm 2-3 git phenolphtalein. Chun bng NaOH 0,1N cho n khi c mu hng nht bn vng trong 30 giy, so snh vi mu i chng l dch cha ln men [6].Cch tnh:Hm lng acid lactic c tnh theo cng thc:(V - Vo) X 0,1 X 90/10 = (V - Vo) X 0,9V: Th tch dung dch NaOH dng trung ha lOml dch ln men (ml) v0: Th tch dung dch NaOH dng trung ha lOml mu i chng (ml)CHNG 4. KT QU V BN LUN4.1 Mt s kho st c im ca Lactobacillus acidophilusGing Lactobacillus acidophilus thun chng do phng th nghim ca trng i hc Bch Khoa TP.HCM cung cp.4.1.1 Quan st vi th, i th

Hnh 13: Hnh nh i th L. acidophilus Sau khi ging Lactobacillus acidophilus c tng sinh trn mi trng MRS lng, chng ti tin hnh kim tra c im hnh thi ca vi sinh vt bng phng php nhum Gram. Ket qu c quan st di knh hin vi in t, vt knh 100. Lactobacillus acidophilus bt mu tm qua phng php nhum Gram do c lp peptidoglycan dy, iu xc nh c Lactobacillus acidophilus l vi khun Gram (+). y l trc khun, c kch thc rng: 0,6 - 0.9|j.m, di: 1.5 - 6.0|im, chng thng tn ti ring l, i khi to thnh chui ngn v c kh nng chuyn ng.

Hnh 14: Hnh nh vi th L. acidophilusSau khi thc hin phng php tri a ging Lactobacillus acidophilus trn mi trng thch MRS. Nhng a mi trng ny c 37c trong 48 gi, chng ti quan st thy khun lc Lactobacillus acidophilus c hnh trn, u, b mtMt t bo c th phn chia theo cp s nhn cho n khi hnh thnh mt khun lc c th trng thy c. y l c s ca vic nh lng t bo trn thch a, bi v s lng khun lc sinh ra t mt th tch ging vi sinh vt nht nh tng ng vi s lng t bo sng ban u c trong th tch ging .4.1.2 Tng sinh ging trn mi trng MRSGing c tng sinh trn mi trng MRS lng sau 24 - 48 gi nui [11].

Hnh 15: Ging Lactobacillus acidophilus trn mi trng MRS lngS lng t bo c xc nh gin tip bng cch m s khun lc mc trn mi trng thch MRS. Mt ging n nh trong khong 5,5 X 107 cfii/ml, mt ging ny cho php a vo qu trnh ln men to sn phm. Mt ging c theo di trong sut thi gian thc hin n nh ti.4.1.3 Chuyn ging vo mi trng trung gian saMi trng sa c tit trng 105c trong 5 pht.Cy ging vi sinh vt vo mi trng sa sau 37c.

Hnh 16: Mi trng trung gian sa c cy ging GVHD: TS. NGUYN THY HNG47SVTH:NGUYNTHQUNHLY




Kho st qu trnh tng trng ca ging trn mi trng sa

Pha tim tng (pha lag) ko di khong 10 gi, y l thi gian vi khun thch nghi vi mi trng trung gian sa. Pha tng trng (pha log) din ra trong 14 gi tip theo. Pha n nh ko di khong 10 gi v bt u gim dn. Kho st ny cho thy thi gian tt nht c thu nhn sinh khi vi khun l t gi th 10 n 24 k t khi cy.Trn thc t chng ti s dng lng sinh khi trung bnh l 5,5 X 107 ci/ml cy vo mi trng dch go. y l lng sinh khi c th chp nhn c nu chng ta so snh vi s lng ging khi u ca mt s sn phm ln men t ng cc nh tng t Amazake lm t go nu chn c lng Lactobacillus amyovorus l 5 - 7 X 106 cfu/ml, sn phm FB (fermented Brown rice) c hm lng Lactobacillus acidophilus l 1,8 X 107 cfu/ml, sn phm yogurt lm t go c hm lng Lactobacillus acidophilus v Lactobacillus casei l 108 - 109 cfu/ml [16,4.2 Kho st nguyn liu go lc4.2.1 Go lcGo lc c mua dng trong sut qu trnh nghin cu c bo qun ni kh ro, thong mt.Bng 4: Thnh phn ha hc ca go lc m(%) chua (ml NaOH 1N/I00g)Protein(gN X 6,25) (%)Lipid (%)Tinh bt(%)ng tng s (%)

6,982,178,171,871,54,6

So vi ti liu ca cc tc gi Juliano (1993) v L Ngc T (1997) chng ti thy hm lng protein ca go lc ang s dng nm trong khong 7,1 - 8,3, gn vi mc 8,76 %. Cht bo th nm trong khong 1,5 - 2,3%, tng ng vi mc 1,87%. Tng lng tinh bt v ng l 76,1% cao hn mc 64 - 73% khng ng k [9,31]- Chng ti quyt nh chn go lc ny cho cc nghin cu tip theo.4.2.2 Dch go lc trc ln menBng 5: Thnh phn ha hc ca dch go lc trc khi ln menProtein (g N X 6,25) (%)Lipid (%)Tinh bt (%)ng tng s

Hm lng0,80,13,773,26

Khi ra protein c th mt i 0,4% v 0,5% khi nu [21], ngha l trong qu trnh x l go thu c dch ln men, hm lng protein c trong go nguyn liu gim i 0,9%. Trong khi , hm lng lipid trong dch go gim rt nhiu so vi lng lipid trong nguyn liu go ban u. Theo l thuyt, phn v la cha nhiu cht x v cht du. Trong qu trnh ngm v xay go, phn v la hng b ph v nhng giai on lc sau khi nu ta vn thy st li cht t nhng v vn nu mm nhn nn buc phi loi b e m bo tnh ng nht v v cm quan cho sn phm.Da vo thnh phn ha hc ca go lc v dch go lc trc khi ln men ta thy tinh bt gim i ch cn 3,77% nhng lng ng tng s tng n 3,26%. iu ny chng t trong qu trnh ngm go cc enzym amylase trong ht go thy phn mt phn tinh bt thnh ng.Nh vy, vi lOOg go lc sau khi ngm 24 gi, xay t ri nu vi 1 lt nc trong khong 25 - 30 pht, lc bng vi mng v trng ta thu c dch go lc st, mu hng nht, c Brix 7-8, pH: 6.5 - 6.6, hm lng protein 0,8%, lipid 0,1%, tinh bt 3,77% v ng 3,26%. Dch go lc ny c chng ti s dng cho qu trnh ln men.4.3 Kho st quy trnh ln men v to sn phmLn men lactic l mt ln men phc tp vi s chuyn ha ng thnh acid lactic di tc dng ca h vi khun lactic. Trong go lc c rt nhiu cht dinh dng vi khun lactic s dng trong qu trnh ln men.Ln men lactic l mt trong nhng ln men rt d b sinh vt tp nhim khc ln vo qu trnh ln men. V vy, tt c cc cng vic cy ging cng nh ln men cn phi thc hin trong iu kin v trng tuyt i.Sn phm mun cnh tranh vi cc sn phm khc cng loi trn th trng v tng tnh cm quan kch thch ngi tiu dng th cn b sung mt s hng liu cng nh ph gia khc to c bn sc c trng ring.4.3.1 Kho st t l go : ncKho st ny nhm tm mt t l go : nc nht nh thch hp cho sn phm v sn phm phi c lng ph hp vi nc ung.Bng 6 : Tng quan gia t l go : ncT l go : ncpHHm lng acid lactic (%)BrixNhn xt cu trc

1 :83.650,9911,5St

1 : 103.590,912Hi lng

1 : 123.630,7312Lng

1 : 143.580,6511,5Lng

1 : 163.720,5612Rt lng

1.2 - 1 ==I 0.81 0.6 =050- 0.4I 0.2 -I0 J!!!!1:081:101:121:141:16T l go:nc th 2: Tng quan gia t l go : nc v hm lng acid lacticng vi t l go 1 : 8 n 1 : 16, pH tng t 3.59 n 3.72, Brix dao ng trong khong 11,5 n 12, hm lng acid lactic dao ng trong khong 0,56 n 0,99. Vi t l go : nc l 1 : 8 v 1 : 10 ta thy kh nng ln men lactic mnh hon cc t l cn li. v cu trc ta nhn thy t l go : nc 1 : 10 l ph hp nht nn chng ti quyt nh chn t l ny, y cng l tin cho cc kho st tip theo.T l nguyn liu : nc l 1: 10 cng l t l thng gp mt s sn phm ln men t ng cc nh Togwa [22] v nhiu sn phm ln men lactic t la m v go ny mm ca nhm tc gi Yoshihide (1997) [23].4.3.2 Kho st t l ng cn b sungT dch go c nu vi t l go : nc l 1 : 10, chng ti tin hnh th nghim ny nhm mc ch tm lng ng b sung ph hp. ng ng vai tr va l c cht thm vo cho vi khun hot ng to acid lactic, va to v ngt cho sn phm.Bng 7: Tng quan gia lng ng b sung v hm lng acid lacticLng ng b sung (g/100ml)pHBrixHm lng acid lactic (%)Mi v ca sn phm

103.59101,08Lt

123.67121,17Ngt, c v chua

143.5513,51,35Ngt

163.5415,51,26Rt ngt

1.6 12 1,4== 19!II1 0.8 O)C 0.61 zE' 0.2 011110121416Lng ng b sung (g/100ml) th 3: Tng quan gia lng ng b sung v hm lng acid lacticng vi lng ng thay i t 10 n 16g/100ml, pH thay i t 3.54 n 3.67. Brix tng t 10 n 15,5, hm lng acid lactic t 1,08 n 1,35. Ta thy ln men lactic mnh dch go c b sung hm lng ng l 14, 16g/100ml, khi b sung t l ng 12g/100ml th sn phm c mi v tt, khi nh gi cm quan c a thch nht nn chng ti chn t l ng l 12g/100ml.Theo Nguyn Ln Dng (1980), ngoi ng lactose, vi khun Lactobacilus acidophius cn c kh nng ln men cc loi ng glucose, saccharose, maltose ...[2]. mt s sn phm ln men lactic t ng cc nh Sobia, Boza, lng ng cng c b sung vi hm lng trong khong 10 - 20% [24, 25].Vi dch go c t l phi trn go : nc l 1 : 10, chng ti quyt nh chn t l ng b sung 12g/100ml cho dch go. T cc kt qu ny chng ti hon tt vic chun b c cht trc khi ln men.4.3.3 Kho st t l gingVi c cht chun b chng ti tin hnh kho st t l ging ban u khi ln men v thu c kt qu nh sau:Bng 8: Tng quan gia t l ging v hm lng acid lacticT l ging (ml ging /100ml dch ln men)pHBrixHm lng acid lactic (%)

13.93120,18

23.69120,63

33.66120,63

43.64120,99

53.61121,71

1.80 1 Co 1.60 J 1.401 1.20 2 1.00 0.80I '60 0.40I 0.20==0.00 -I1111112345Nng ging (%) th 4: nh hng ca t l ging ban u n hm lng acid lacticDa vo kt qu trn ta thy, cng mt mt ging ban u khong 5,5 X 107 cfu/ml, t l ging t 1% n 5% cho hot tnh ln men tng dn, hm lng acid lactic tng t 0,18 n 1,72. Khi thay i nng ging cay, pH thay i t 3.61 n3.93, Brix l 12. Thi gian ln men l mt vn quan trng v ph thuc bi nhiu yu t nh nhit , pH... m quan trng l cht lng v s lng ging vi sinh vt. Chng ti quyt nh chn t l ging 5% rt ngn thi gian ln men.Tng kt phn kho st iu kin ln men, mt s kt qu c a ra yu t ti u cho s ln men lactic t go lc nh sau:T l go : nc l 1 : 10T l ng cn b sung l 12g/100mlNng ging cy thch hp l 5%.4.4 KHO ST HNG LIU B SUNG THCH HP V NH GI CHT LNG CM QUAN CHO SN PHMSau khi thu nhn dch ln men, chng ti b sung t 0,15% hng du, hng cam cho mi thm nh nhng, hng sa t nhin v cho tip khong 0,2% dung dch mu du nhm to mu hng t- nhin ca go lc. y cng l cng on cui cng ca quy trnh to sn phm [7].nh gi cm quan l mt phng php khoa hc dng gi ln, o c, phn tch v gii thch nhng thng tin thu c t sn phm thng qua cm nhn ca cc gic quan: th gic, khu gic, xc gic, v gic v thnh gic [9]. Phng php nh gi cm quan phn nh nhn thc v c im sn phm m con ngi cm nhn vn d l mt thiu st ca cc phng php o c bng dng c. Chnh v vy, vic ng dng nh gi cm quan v ang pht trin khng ngng trong cng ngh thc phm, t nghin cu v pht trin sn phm n qun l cht lng.T 3 sn phm khc bit v hng v mi chng ti tin hnh nh gi cm quan sn phm qua 2 phng php l php th cho im th hiu v php th cho im cht lng vi 3 mu sn phm.Php th cho im th hiu l php th c thc hin trn s ng ngi tiu dng tm hiu mc hi lng, a thch ca h i vi sn phm nghin cu. iu quan trng nht khi tin hnh php th ny l cng vic quy hoch i tng ngi th hay cn gi l la chn nhm ngi tiu dng mc tiu ca sn phm. Cc yu t nn quan tm l: la tui, gii tnh, thi quen tiu dng...Php th cho im cht lng c s dng nh gi tng qut mc cht lng ca mt sn phm so vi tiu chun hoc so vi mt sn phm cng loi trn tt c cc ch tiu cm quan: mu sc, mi, v, trng thi. Tnh trng cht lng ca mi ch tiu c nh gi bng im. Gi tr im tng theo mc tng ca cht lng. Ty theo sn phm v quc gia m thang im s dng rt khc nhau [9].Mu A: Hng du Mu B: Hng cam Mu C: Hng sa t nhinCc mu c s dng nh gi cm quan th hiu gm 30 ngi tham gia th mu.Bng php th cho im thi hiuBng 9: im nh gi ca 30 ngi tham gia cm quan, ngh nghip sinh vin, tui t 18-22STTMu AMu BMuC

1676

2877

3685

4567

5867

6786

7776

8777

9686

10586

11877

12685

13767

14877

15675

16787

17878

18676

19785

20768

21577

22886

23877

24688

25784

26577

27898

28685

29797

30786

Tng202222193

Trung bnh6,77,46,4

Nhn xt: Ph gia cng c nh hng nhiu n a thch chung ca sn phm. Mu B (hng cam): c tng s im l 222, xp v tr th 1 Mu A (hng du): c tng s im l 202, xp v tr th 2 Mu c (hng sa t nhin): c tng s im l 193, xp v tr th 3 Vi thang im 6 (hi thch) v 7 (thch va phi) th cc mu A, B, c u th c chp nhn.CC BC PHN TCH PHNG SAI H s hiu chnh (HC)H s hiu chnh bng bnh phng tng chia cho s cu tr li H s hiu chnh = (tng)2 / s cu tr li HC = (202 + 222 + 193)2 / 90 = 4239e ti: Th nghim to thc ung ln men lactic t- go lc Tng bnh phngTng bnh phng mu (TBPm) bng tng bnh phng tng im ca mi mu chia cho tng s cu tr li ca tng mu tr cho h s hiu chnh.TBPm = (202)2 + (222)2 + (193)2 /30 - 4239 = 14,7Tng bnh phng ngi th (TBPtv) bng tong bnh phng tng im cho bi mi ngi th chia cho s cu tr li ca tng ngi ri tr i h s hiu chnh. TBPtv = [(6+7+6)2 + (8+7+7)2 + ...+ (7+9+7)2 + (7+8+6)2)/3 -4239 = 27,8Tng bnh phng ton phn (TBPtp) bng tng bnh phng ca tng im tr i h s hiu chnh (HC)TBPp = [(62 + 72 + 62) + ... +(72 + 82 +62)] - 4239 = 95,1Tng bnh phng d (TBPSS) = TBPtp - TBPm - TBPtv = 95,1 - 14,7-27,8 = 52,6 Tnh s bc t do: Bc t do ca i lng no bng tng i lng trcho 1Bc t do ca mu (Btdm) bng tng s lng mu tr cho 1 Btdm = 3-1=2Bc t do ca ngi th bng s ngi th tr cho 1 Btdtv = 30 - 1 = 29Bc t do tng (Btdtp) bng tng s cu tr li tr cho 1 Btdtp= (30 X 3) - 1 = 89Bc t do ca sai s (Btdss) bng bc t do tng tr cho tng bc t do ca ngi th v bc t do ca mu Btdss = 89 - 29 - 2 = 58Tnh bnh phng trung bnhBnh phng trung bnh (BPTB) i vi mt bin no l thng s ca tong bnh phng chia cho s bc t do tng ng:BPTBm = 14,7/2 = 7,35 BPTBtv = 27,8/29 = 0,96 BPTBSS = 52,6/58 = 0,91e ti: Th nghim to thc ung ln men lactic t- go lc Tnh tng quan phng saiTng quan phng sai ca mu (Fm) l bnh phng trung bnh ca cc mu chia cho bnh phng trung bnh ca sai s Fm = 7,35/0,91 =8,01Tng quan phng sai ca ngi th (Ftv) l bnh phng trung bnh ca ngi th chia cho bnh phng trung bnh ca sai s Ftv = 0,96/0,91 = 1,05Cc tnh ton trn c tng hp li trong bng phn tch phng saiBng 10: Phn tch phng saiNgun gc phng saiBtdTBPBPTBF

Mu214,77,358,01

Ngi th2927,80,961,05

Sai s5852,60,91

Tng8995,1

So snh gia cc mu

Gi tr F i vi cc mu l 8,01. Do bc t do ca sai s l 58 khng c trong bng ph lc nn ta chn Btd sai s l 00, Btd mu l 2. Vy gi tr Ftc tra t ph lc l 2,89, tng ng vi ct =2 (s bc t do ca mu) v hng n2 = 00 (s bc t- do ca sai s). Ta nhn thy F < Ftc nn c th kt lun c rng cc mu khc nhau c ngha, mc ngha 5% [9].GVHD: TS. NGUYN THY HNG68SVTH: NGUYN TH QUNH LY

Bng 11: Ket qu ca php th cho im th hiu Phng th nghim phn tch cm quanBO CO TH NGHIM Php th cho imSn phm ling ln men lactic t go lcMc ch: So snh mc yu thch ca ngi th i vi 3 mu thc ung ln men lactic t go lc c m s A, B, c c b sung cc hng liu cam, du v hng sa.M t th nghim: Hi ng cm quan gm 30 ngi c ngh nghip l sinh vin, tui t 18 - 22. Mi ngi nhn c 3 mu dch go lc ln men vi 3 mi v khc nhau, mi mu 15ml. Mu th c lu gi trong nhit lnh t 4 - 6 c. Trong th nghim s dng phng php phn tch phng sai x l s liu.Ket qu: Ket qu phn tch phng sai ch ra s khc bit v mi v gia cc mu A, B, c mc ngha 5%. Mu B (hng cam) c yu thch nht, k n l mu A (hng du) v cui cng l mu c (hng sa t nhin). Cc mu u nm trong mc hi thch v thch va phi ca ngi th.Bng php th cho im cht lngChng ti chn mu B (hng cam) xp v tr cao nht trong kt qu php th cm quan th hiu nh gi cht lng bng php th cho im cht lng theo TCVN 3215-79Nhn xt: Da vo im trung bnh c trng lng v bng TCVN tm xy dng cho ung ln men lactic t go lc (ph lc), chng ti nhn thyv mu sc: t im trung bnh l 4,2/5 tng ng vi m t Trng thi mu sc tng i ng u, hi c trng.v cu trc: t im trung bnh l 4,1/5, tng ng vi m t Dch ln men hi snh, cu trc tng i ng uv mi: t im trung bnh l 4,3/5, tng ng vi m t Mi thm nhv v: t im trung bnh l 3,8/5, tng ng vi m t V chua ngt t hiha,.e ti: Th nghim to thc ung ln men lactic t- go lc

Bng c hai phng php nh gi cm quan, chng ti thu c kt qu: sn phm cht lng loi khGVHD: TS. NGUYN THY HNG70SVTH: NGUYN TH QUNH LY

Bng 12: Ket qu ca php th cho im cht lngPhng th nghim phn tch cm quanPHIU NH GI KT QU CM QUAN Php th cho im cht lng TCVN 3215 - 79 Sn phm: ung ln men lactic t go lc (Hng cam)Ngy th: 12/06/2008Chtiuim tng thnh vinTngTrung bnh cha c trong lngH s trng lngTrungbnhctrnglng

TV1TV2TV3TV4TV5TV6TV7TV8TV9

Musc445435544384,214,2

Cutrc544534345374,10,83,28

Mi455453445394,314,3

V353435443343,81,24,56

im cht lng16,34

Ket qu: sn phm xp loi: KhTh k hi ng cm quanChtchhi ng cm quan(xc nhn)(xcnhn)4.5 Thi gian bo qun sn phmBng kt qu nh gi cm quan chng ti chn c mu ti u l mu c t l go : nc l 1:10, hm lng ng b sung l 12g/100ml v t l ging l 5%. Chng ti tin hnh xc nh thi gian bo qun thng qua cc ch tiu dinh dng, vi sinh, cm quan...Trong cc ch tiu th chng ti c bit ch n ch tiu vi sinh.Do trn th trng cha c sn phm tng t, vi nh hng ban u ca sn phm, chng ti so snh vi ch tiu vi sinh bt buc dnh cho sa chua khng x l nhit theo TCVN 7030 : 2002. Tng s vi khun hiu kh cho phcp l 104 t bo/g, Cli/onn l 10, tng s nm men nm mc l 10, cc vi sinh cn li l 0 [14]. Trong cc ch tiu th tng s vi khun hiu kh l quan trng nht.Bng 13: Theo di s pht trin ca tng s vi khun hiu khTunTng s vi khun hiu kh

02 X 102

1103

23,3 X 103

38,6 X 103

Nhn xt: Theo TCVN 7030 : 2002, tng s vi khun hiu kh cho php l 104. Kho st tng s vi khun hiu kh ca sn phm cho thy t tun th 0 - 3, s lng vi khun hiu kh nm trong khong 2 X 102 - 8,6 X 103, vn cn nm trong tiu chun cho php, sn phm an ton i vi ngi s dng. V vy, sn phm c th s dng c trong thi gian t nht 3 tun t khi ln men trong iu kin bo qun nhit lnh 4 - 6c.Hot tnh ProbioticTng s vi khun Lactobacillus acidophilus ca sn phm l 2,7 X 107. Khi so snh vi lng vi khun lactic tn ti trong cc sn phm ln men lactic t ng cc khc nh sn phm ung cng sinh t yn mch vi s lng Lactobacillus acidophilus l 6,77 X 107 cfu/ml, Lactobacillus plantarum l 1,77 X 106 ci/ml, slng vi khun lactic cn li l 7,39 X 107 cli/ml, sn phm Boza vi s lng vi khun lactic l 4,6 X 1 o8 cfli/ml, sn phm Kunun - zaki c s lng Lactobacillus plantarum l 7,3 X 107 cfi/ml, th s lng vi khun lactic trong sn phm ca chng ti l hon ton c th chp nhn c [30, 31, 34],Chng ti theo di hot tnh Probiotic ca sn phm trong 3 tun, bo qun iu kin nhit 4 - 6c. Sn phm khng s dng bt k loi ha cht no. Cc ch tiu cn theo di gm: pH, s lng vi khun lactic v nhn xt v cu trc.Bng 14: Hm lng vi khun lactic trong iu kin ct gi nhit 4 - 6cThi gian (tun)pHS lng vi khun lactic (cfii/ml)Nhn xt v cu trc

03.74,1 X 107Cu trc n inh

13.63,5 X 107

23.62,9 X 107

33.52,7 X 107

Sn phm Oats - based symbiotic beverage, khi nghin cu s tn ti ca ring Lactobacus acidophius trong thi gian bo qun 4 tun, sinh khi gim t6, 77 X 107 cfii/ml (trc bo qun) n tun th 4 l 5,55 X 105 cfu/ml. Ngc li cc ch tiu acid lactic 0,22% v pH: 3.63 ca sn phm li thay i khng ng k trong sut thi gian 10 tun [31].Nh vy trong iu kin bo qun nhit lnh 4 - 6c, theo bng 14 th sn phm ung ln men lactic t go lc vn duy tr c hot tnh Probiotic theo nh hng mc ch ca ti (2,7 X 1 o7 4,1 X 107).

CHNG 5. KT LUN V NGH5.1 Ket lunTrn c s qui trnh to ung ln men lactic t ng cc nh Boza, Sobia, Kunun - zaki ... [16, 25, 26, 27, 32, 33], chng ti xy dng c qui trnh to sn phm Probiotic dng ung ln men lactic t go lc nh sau:

Go lc (100g)

Ra schNgm nc trong 24 giGn nc, ra sch goNghinB sung nc vi t l go : nc l 1 : 10Nu si v khuy u khong 30 phtXay nhuynLc bng vi v trng

Ln men trong 24 gi, pH:5, nhit 37c

S 4: Qui trnh to thc ung ln men lactic t go lc Qua kho st cc iu kin ln men v nh gi cm quan, chng ti la chn c mu sn phm hon thin nht vi t l go : nc l 1 : 10, t l ng l 12g/100ml dch go, nng ging vi sinh vt b sung vo dch ln men l 5% ging, sn phm b sung hng cam l c yu thch nhtHp thanh trng 95c trong 30 phtLm ngui n 37cng chaiCt gi sn phm 4 - 6c

Vi qui trnh to sn phm nh trn, sn phm c th bo qun c nhit t 4 - 6c t nht l 3 tun, tng s vi khun lactic l 2,7 - 4,1 X 107. Sn phm t cht lng cm quan c nh gi vo loi kh.y l mt sn phm Probiotic c qui trnh n gin, nguyn liu d kim v hon ton c th thc hin c trn qui m gia nh. T nhng kt qu m chng ti t c hy vng s l tin cho nhng nghin cu su hn nhm gp phn hon thin sn phm.5.2 e nghV y l mt sn phm mang nhiu trin vng tt, chng ti mong mun c nhiu nghin cu su v m rng hn na. Chng ti c mt s ngh:Tip tc tin hnh kim tra cc ch tiu vi sinh xc nh cht lng snphm.Bo qun v theo di sn phm t tun th 3 tr ln kho st tng s vi khun hiu kh v vi khun lactic, t a ra thi gian bo qun chnh xc cho sn phm.Nghin cu tng sinh ging vi sinh vt tt hn c th a sinh khi vi khun Lactobacillus acidophius ban u ln ti 108, 109, IO10 cfu/ml nhm rt ngn thi gian ln men v gim t l ging cy.Nghin cu v so snh kh nng ln men ca nhiu loi vi khun lactic nh: Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus amyovorus... c th la chn thm cc ging ph hp khc ngoi Lactobacillus acidophilus m chng ti s dng. Nghin cn v xc nh t l phi gia cc ging cy.Nghin cu b sung ngun m v lipid vo c cht chnh l go lc nng cao cht lng sn phm. Ngun m thm vo c th t bt u nnh, ngun lipid t cc loi du thc vt.Nghin cu s dng go lc ny mm thay cho nguyn liu go lc ban u. Khi s dng nguyn liu go lc ny mm s lm gia tng hm lng Y- aminobutyric (GABA) gp 3 ln so vi go ngm trong iu kin thun li. Chng ta s c mt sn phm ung ln men lactic t go lc ngoi chc nng Probiotic cn c thm vai tr ngn chn s pht trin ca t bo ung th.[9].GVHD: TS. NGUYN THY HNG#SVTH: NGUYN TH QUNH LY


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