bÁo cÁo thỰc hÀnh cÔng nghỆ lÊn men truyỀn thỐng

Bo co: TH CNLMTT

GVHD: TS. Nguyn Hoi Hng NI DUNG THC HNH

Bi 1: LN MEN BIA.................................................................................................2 Nguyn liu..............................................................................................................2 Dng c: .................................................................................................................3 Tin hnh th nghim: .............................................................................................4 Nguyn liu:..........................................................................................................24 Dng c:................................................................................................................24 Nguyn vt liu......................................................................................................39 Dng c..................................................................................................................40 Cc bc thc hin................................................................................................41

Nhm 6|08DSH2

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Bo co: TH CNLMTT

GVHD: TS. Nguyn Hoi Hng

Bi 1: LN MEN BIA

Bia l loi ung b dng, c cn thp, c mn xp, hng v c trng bt ngun t Ai Cp c i. Hng v v ca bia do c c n g u y n l i u t c n , C O 2 v c c s n phm ln men khc to nn. c bit l CO2 c tc dng lm gim nhanh cn kht ca ngi ung. Nh nhng u im ny m bia c s dng rng ri trn th gii v sn lng ngy cng tang c du nhp vo Vit Nam hn mt tram nm nay.

Nguyn liu Malt

Nhm 6|08DSH2

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Bo co: TH CNLMTT Hoa bia (hoa Houblon)


Nm men Saccharomyces carlsbergensis

Dng c: a Petri, ng nghim, bnh tam gic, my lc, t sy, my ly tm, t trng k, Brix k, b chng ct cn,

Nhm 6|08DSH2

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Bo co: TH CNLMTT Tin hnh th nghim: Quy trnh cng ngh ln men bia


Malt 200g

Nghin Nc Phi trn Malt:H2O=1:4

Nu malt BTo=76oC PH=5,5 o Br=12o to=76-78oC to=8oC

Lc ra b

Nu hoa biaMen ging trong ng thch nghing

Lm lnh nhanh10% Cy ging

Mi trng YEPG( t l mi trng = 50:1) 37oC, lc trong 3 ngy

Ln men chnh Thu bia non non Phn tch cc ch tiu

to=8oC PHu =5,2-5,6 PHcui =4,4-4,5 PHi=4,4-4,5

ln menNhm 6|08DSH2

Nng cnTrang 4

Bo co: TH CNLMTT


Chun b men ging:Men chm ly t bn ln men chnh ca nh my bia Vinaken Cy vo ng thch nghing cha mi trng Hansen gi 37oC 50ml mi trng:1ml ging Cy vo mi trng YEPG u 370C Lc trong 3 ngy Cy vo bnh ln men chnh Ging phi t s lng t bo 15 - 20.107 t bo/ml

Mc ch :Cy vo ng thch nghing cha mi trng Hansen u 370C/24h nhm gi ging Cy t mi trng Hansen vo mi trng YEPG nhm to mi trng khi ng ging nh mi trng ln men qu trnh ln men thun li din ra nhanh v pha khi ng gim cng ngn cng tt. Chun b mi trng: Mi trng Hensan: Saccharose/Maltose 50g/l Pepton KH2PO4 MgSO4 Agar Mi trng YEPG: Nhm 6|08DSH2 Trang 5 10g/l 3g/l 3-5g/l 20g/l

Bo co: TH CNLMTT Yeast extract Peptone Glucose 5g/l 10g/l 20g/l


Xy dng ng chun t bo: Lng t bo nm men, c th biu din bng gi tr mt quang OD o c hoc c th xy dng ng cng tiu chun, biu th mi lin quan gia c vi nng t bo t y c th bit c lng t bo/ml dch. + Chun b mu o OD Ly 1ml dung dch huyn ph cho vo eppendorf. Tng cng l 8 eppendort. Sau em ly tm 10000 vng/pht trong 12 pht. Thu dch lng thm 1ml nc mui sinh l vo ta c dch huyn ph 1. Thm 31ml nc mui sinh l cho vo dch huyn ph 1 ta c dch huyn ph 2, pha long 32 ln. Tin hnh o OD theo cc nng sau ta c kt qu: Dch huyn ph 2 (ml) Nc mui sinh l (ml) Kt qu (OD) 4 0 0,486 3,5 0,5 0,433 3 1 0,387 2,5 1,5 0,330 2 2 0,257 1,5 2,5 0,221 1 3 0,136 0,5 3,5 0,072 th ng chun OD

Nhm 6|08DSH2

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Bo co: TH CNLMTT0.6 0.5 0.4 OD 0.3 0.2 0.1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 y = 0.118x + 0.0249 2 R = 0.994


4.5

Mu t bo nm m en

T mi trng YEPG trn qua thi gian lc sau 3 ngy ta tin hnh nhn ging theo phng php tri a trn mi trng Hansen vi cc nng pha long nh sau:

-

10-1 (ly 1ml dch mu sang ng nghim cha 9ml nc mui sinh l hp kh 10-2 (ly 1ml dch mu 10-1sang ng nghim cha 9ml nc mui sinh l hp kh 10-3 (ly 1ml dch mu 10-2sang ng nghim cha 9ml nc mui sinh l hp

trng, lc u )-

trng, lc u )-

kh trng, lc u ) Nhm 6|08DSH2 Trang 7

Bo co: TH CNLMTT-


10-4 (ly 1ml dch mu 10-3sang ng nghim cha 9ml nc mui sinh l hp kh 10-5 (ly 1ml dch mu 10-4 sang ng nghim cha 9ml nc mui sinh l hp 10-6 (ly 1ml dch mu 10-5 sang ng nghim cha 9ml nc mui sinh hp kh 10-7 (ly 1ml dch mu 10-6 sang ng nghim cha 9ml nc mui sinh l hp

trng, lc u )-

kh trng, lc u )-

trng, lc u )-

kh trng, lc u v ly 0.1ml vo a mi trng v trang u n khi kh hon ton) 3 a-

10-8 (ly 1ml dch mu 10-7 sang ng nghim cha 9ml nc mui sinh l hp





kh trng, lc u v ly 0.1ml vo a mi trng v trang u n khi kh hon ton) 3 a Vi 12 a ta c kt qu sau 3 ngy cy nh sau: 10-7: 29 10-8: 16 10-9 : 10 10-10 : 7

Do thao tc sai nn mt s mu b nhim nn cho kt qu rt thp, ta chi ly 10 -7, cn cc kt qu khc khng ly v s khun lc < 25 khun lc. mt pha long l 10-7 s khun lc trung bnh l: 29 khun lc.

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Bo co: TH CNLMTT Vy ta c mt t bo gc l:2,9 10 9 = 9,1x107 3229 10 7 0,1

GVHD: TS. Nguyn Hoi Hng = 2,9x109cfu/ml

=> So =

Ta c phng trnh ng chun OD: y = 0,118x + 0,0249 Nng t bo cc mc pha long l: 4ml mu t bo pha long 32 ln : X4 = So = 9,1x107 3,5ml mu t bo pha long 32 ln v 0.5ml nc mui sinh l: X3.5 =3,5 S 0 3,5 9,110 7 = = 7,96x107 cfu/ml 4 4

3ml mu t bo pha long 32 ln v 1ml nc mui sinh l: X3 =3 S0 3 9,110 7 = = 6,825x107 cfu/ml 4 4

2,5ml mu t bo pha long 32 ln v 1,5ml nc mui sinh l: X2,5 =2,5 S 0 2,5 9,1 10 7 = = 5,69x107 cfu/ml 4 4

2ml mu t bo pha long 32 ln v 2ml nc mui sinh l: X2 =2 S0 2 9,1 10 7 = = 4,55x107 cfu/ml 4 4

1,5ml mu t bo pha long 32 ln v 2,5ml nc mui sinh l: X1,5 =1,5 S 0 1,5 9,1 10 7 = = 3,41x107 cfu/ml 4 4

1ml mu t bo pha long 32 ln v 3ml nc mui sinh l:

Nhm 6|08DSH2

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Bo co: TH CNLMTT X1 =1 S 0 1 9,1 10 7 = = 2,28x107 cfu/ml 4 4


3ml mu t bo pha long 32 ln v 1ml nc mui sinh l: X0,5 =0.5 S 0 0,5 9,110 7 = = 1,14x107 cfu/ml 4 4

pha long (ml) 4 3.5 3 2.5 2 1.5 1 0.5

OD 0,48 6 0,43 3 0,38 7 0,33 0 0,25 7 0,22 1 0,13 6 0,07 2

Nng t bo (cfu/ml) 9,1x107 7,96x107 6,825x107 5,69x107 4,55x107 3,41x107 2,28x107 1,14x107

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Bo co: TH CNLMTT th ng chun t bo0.6 0.5 0.4 OD 0.3 0.2 0.1 0 0 1E+07 2E+07 3E+07 4E+07 5E+07 6E+07 CFU/ml 7E+07 8E+07 y = 5E-09x + 0.0247 R2 = 0.994


9E+07 1E+08

Nhn xet: sau khi o OD va trai ia trn mi trng Hansen ta dng c thi

ng chun t bao, xac inh mt t bao nm men co trong mi trng YEPG trc khi cy vao binh ln men chinh la 9,1x107CFU/ml, nh hn so vi mc ging qui inh phai at s lng t bao la 15-20x107 CFU/ml. Chun b nguyn liu: Malt: Xay malt bng my xay phng th nghim. Nu malt: malt : nc=1:4 nu theo quy trnh nu theo s : Cn 200g malt cho vo 2 cc mi cc 100g malt. Thm nc vo mi cc l 400ml. Sau tin hnh nu theo gin sau:

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Bo co: TH CNLMTT


Lc qua giy lc: Lc v ra b nc nng 760C

Malt sau khi nu Lc th bng bng gn Dch 1 B

o Brix = 8O thm 200ml nc(760C) V= 380ml Dch 2

Dch 1+ Dch 2 Lc tinh bng lc chn khng Pha loang bng nc 760C a v Brix= 120Br, V=900ml un ln 760C Thm 0.5ml dch hoa Houblon un ln 760C Nhm 6|08DSH2 Trang 12

Bo co: TH CNLMTT

GVHD: TS. Nguyn Hoi Hng Lm lnh xung 80C

Nu hoa bia: Sau khi lc tin hnh nu hoa 76oC gi 10 pht ng ha ht

phn ng cn li to v ng v to hng cho bia un si dch ng 10min th cho hoa bia vo to v ng Trc khi kt thc 10min cho hoa bia vo to hng.

Lm lnh nhanh Sau khi nu hoa nhanh bng nc a dch ng v 8oC. tin hnh cy ging. Cy ging: Ly ging t 2 binh tam giac cha nm men tng sinh trong mi trng

YEPG a c lc trong 3 ngay cy ging trong iu kin v trng. T l cy ging 10%.

Ln men chnh: Ln men trong 2 bnh thy tinh mi bnh 500ml. y bnh bngnt bng v c bao bng bong bng cao su. bnh ln men nhit 8oC v trong 7 ngy.

Lc v thu bia non: Sau khi ln men chnh h nhit xung 2oC ln men phv kt lng nm men y bnh ri tin hnh lc chn khng thu dch bia non. Phn tch: 1) Phn tch nguyn liu: a. Xc nh m malt:

Dng c:My nghin trc phng th nghim. T sy Bnh ht m Cn phn tch Nhm 6|08DSH2 Trang 13

Bo co: TH CNLMTT Tin hnh


Ly ngay khong 3g bt nghin vo cc cn sch kh bit trc trng lng. y np v cn vi chnh xc 0,001g. M np, c cc v np vo t sy t nhit 105oC bt u tnh thi gian khi t sy t nhit trn. Sy trong 3 gi, y np, ly cc cn ra lm ngui trong bnh ht m v nhit phng 20 pht ri cn. Sy li hn 1 gi na v cn li vi chnh xc 0,001g. Kt qu o m: Khi lng mu ban u (mmu) (g) 3 3 3 W = . 100% W1 = . 100% =60 ,354 60 ,142 .100%=7,07% 3 62 ,876 62 ,665 .100%=7.03% 3 62 ,382 62 ,176 .100%=6,87% 3

Khi lng cc (g) 57,354 59,876 59,382

Khi lng mu + cc ban u (m0) (g) 60,354 62,876 62,382

Khi lng mu + cc sau sy (m1) (g) 60,142 62,665 62,176

W2 = . 100% =

W3 = . 100% =

WTB =

7,07 + 7,03 + 6,87 = 6.99% 3

b. Xc nh ha tan ca malt: Cn khong 55g malt v nghin, trn u, ly ra mt phn nh xc nh m.t nhit bnh iu chnh nhit 45oC

Nhm 6|08DSH2

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Bo co: TH CNLMTT


Cn chnh xc 50g malt nghin cho vo cc bit trng lng, ri rt vo cc 200ml nc ct 46oC, dng a thy tinh khuy cho khi vn cc, trnh to bt. Gi cc 45oC trong 30 pht, khuy lin tc. Tng nhit ln 70 vi tc 1oC/1 pht. Khi nhit t 70 rt thm vo 100ml nc ct 70oC. C 5 pht ly mu 1 ln th dch ng ha bng cch ha 1 git I2 0,02N vi mu n khi mu c mu vng rm (khng lm mt mu dd I2) coi nh ng ha kt thc. Thi gian t khi hn hp trong cc t 70oC n khi khng lm mt mu I2 gi l thi gian ng ha. Nu qu trnh ng ha khng kt thc sau 1h th nghim th ngng li, hoc lm li, hoc thay i lng malt. Tip tc gi nhit 70 trong 1 gi (tnh t khi t 70oC), sau ly cc ra v lm ngui n nhit phng trong khong 10 -15 pht. Ra u a khuy bng nc ct. lau kh bn ngoi cc v em cn li sao cho trng lng trong cc t khong 450g bng cch b sung thm nc ct. Khuy u ri ton b lng dch lc vo phu lc. lc li 100ml dch lc ban u ri mi tnh thi gian lc . Ly mt phn dch lc xc nh mu. Qu trnh coi nh kt thc khi b mt b trn mt kh hoc qu trnh lc chm( ko di qu 2h) Kt qu: Brix = 80 Tra bng ph lc 8 => Hm lng cht ha tan ca dch ng e = 8,2% ha tan ca malt: E1 = =8,2 x (6,99 + 800 ) (100 8,2)

= 72,08% Trang 15

Nhm 6|08DSH2

Bo co: TH CNLMTT ha tan ca malt tnh theo cht kh tuyt i: E2 =E1 x100 72 ,08 x100 = (100 6,99 ) = 77,50% (100 W )


c. Nng lc ng ha ca malt: Cc bc tin hnh: Ha cht: Nc ct Dung dch m axetat pH = 4,3 Cn 30g a.acetic ha tan vi nc v nh mc 1l. Cn 34g Natri axetat (NaC2H3O2 . 3H2O) ha tan vi nc v nh mc ti 500 ml. Trn 2 dung dch ny n khi t c pH = 4,3 250C. Dung dch tinh bt 20g/l. Cn 1 lng tinh bt tan tng ng vi 10g cht kh v khuy 1 cht nc lnh n dng huyn ph. Thm vo 400 ml nc si, khuy v gi hn hp lun si. Ra a khuy bng mt cht nc lnh v cho vo dung dch tinh bt, un si 5 pht. t cc v nc lnh v khuy hn hp lm ngui, trnh to mng. nh mc: 500 ml. Dung dch it: 0.1N. Cn 12.7g it v 20g KI, ha tan vo 200ml nc. nh mc 1l. Dung dch Na2S2O3 : 0.1N. Cn 24.82g Natri thiosulfat Na2S2O3.5H2O + 7.6g Na2B4O7.10H2O. Ha tan trong 300-400 ml. nh mc 1l. NaOH 1N H2SO4 0.5N Dung dch thymol phtalein 5g/l. Cn 0.5g v ha tan trong 100ml etanol 96%. Dng c: my nghin, cn phn tch, cc thy tinh, bp cch thy iu nhit, phiu lc, giy lc, bnh tam gic, bnh nh mc 250ml, pipet... Nhm 6|08DSH2 Trang 16

Bo co: TH CNLMTT Tin hnh Cn 20g vng nht cho vo cc nu


Thu dch chit: un bp cch thu ti nhit 40oC, rt 480ml H2Olnh vo mu matl. Khuy u trnh vn cc, t cc vo bp cch thu 40 oC khuy lin tc trong vng 1h. Lm ngui dch chit ti nhit phng, ra a khuy bng mt t nc lau kh pha ngoi cc, iu chnh khi lng cc ti 520. Lc: khuy tht u dch chit, b ngay ton b hn hp vo phu lc, loi b 200ml dch lc u, ly 500ml dch lc sau phn tch Thu phn dung dch tinh bt

+ Mu th nghim: Dng pipet ly 100ml tinh bt vo bnh nh mc 250ml, them6,5ml dung dch m axetat, t vo bnh cch thu 20oC, yn trong 20 pht. Cho tip 6,5ml dch chit matl lc vo hn hp trn, lc u ri tip 20oC ng 30 pht tnh t lc b them dch chit matl. Sau cho 5ml NaOH ngng hot ng c enzyme, them nc ti vch nh mc v lc u. Kim tra kim bng cch nh mt git phenolphetalein hn hp c mu hng + Mu kim chng: 100ml tinh bt cho vo bnh nh mc 250ml, cho them 5 ml dd NaOH, lc u, them 6,5ml dch chit, them nc nh mc 250 ml ri lc u. Xc nh ng kh theo phng php iod: Ht 50ml dung dch cho vo bnh tam gic 250ml, them 25ml dd iod v 3ml dd NaOH, sau lc u, y nt bnh trnh tn tht iod. S dng Na2S2O3 0.1N chun n khi mt mu hng. Kt qu: Cng thc tnh nng lc ng ha: DP1 = F(VT - VB) VB: th tch Na2S2O3 dng d chun iod d trong mu i chng. Nhm 6|08DSH2 Trang 17

Bo co: TH CNLMTT


VT: th tch Na2S2O3 dng d chun iod d trong mu th nghim. F=34,2: h s chuyn i tnh kt qu theo 100g malt dng chit enzyme. DP2 = DP1: nng lc ng ha ca malt DP2: nng lc ng ha ca malt tnh theo cht kh tuyt i

Nhm Mu i chng (ml) Mu th nghim (ml) DP1(WK) DP2(WK) N1 7 10,5 119,7 128,69 N2 7 7,4 13,68 14,71 N3 7 7,6 20,52 22,06 N4 6,8 9,5 92,34 99,28 N5 6,8 10,5 126,54 136,05 N6 7 11,2 143,64 154,44 V lng It phn ng trong khong 6 - 12 ml Na2S2O3 0.1N nn s liu ca nhm 6 l t yu cu xc nh nng lc ng ha ca malt. Cn s liu nhm N2 v N3 khng chp nhn c v s qu nh do thao tc sai. Tin hnh so snh cht lng malt ca nh my bia Sai Gn vi mu malt em i th nghim. Bng so snh cht lng malt ca nh my bia Si Gn vi mu th nghim tt nht: Tn ch tiu Bia Si Gn Th nghim m (%) 45 6.99 ha tan (%) >80 77,50 Nng lc ng (WK) 290 320 154,44

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Bo co: TH CNLMTT Kt lun:


m m ca malt em th nghim l cao hn so vi ch tiu cht lng malt ca

nh my bia Si Gn do: + + + + iu kin bo qun malt ca phng th nghim khng c tt Malt mua vo khng c bo m cht lng. m cao c th nh hng n qu trnh sn xut bia nh: m cao nh hng n qu trnh bo qun malt. m cng cao lm cho ha tan ca cht kh gim v nng lc ng ha

cng gim. + + Gim nng xut v cht lng ca bia. Gim hot ho, tch lu v khi lng v hot lc ca h enzin trong i mch.

ha tan trn cht kh xay nhuyn ha tan ca cht kh nh hn so vi ch tiu cht lng malt ca nh my bia Si Gn do: + + iu kin bo qun malt ca phng th nghim khng c tt Malt mua vo khng c bo m cht lng.

ha tan thp lm nh hng n cht lng bia nh:

Nhm 6|08DSH2

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Bo co: TH CNLMTT +


ha tan thp lm cho lng cht kh trong malt ha tan vo dung dch thp

nh hng n cht lng ca dch ng lm cht lng bia khng t yu cu. Nng lc ng ha: Nng lc ng ha ca malt lm th nghim li thp hn so vi ch tiu nng lc ng ha ca malt nh my bia Si Gn do: + + + + m trong malt cao gy cn tr hot lc ca diastase. iu kin bo qun malt khng c tt Malt mua vo khng kim sot c cht lng. Hot lc ca diastase thy phn thnh ng maltose yu.

Nng lc ng ha khng tt dn n hot lc ca enzyme c trong malt gim lm nh hng n qu trnh ng ha lm hiu sut ln men gim v cht lng ca bia khng t yu cu. 2) Tin hnh phn tch cc ch tiu sau khi ln men bia:

Nhm 6|08DSH2

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Bo co: TH CNLMTT

GVHD: TS. Nguyn Hoi Hng Qu trnh chng ct cn

a. Nng ru: Xc nh nng ru ca bia bng phng php chng ct v s dng cn k o nng ru. Gi tr c th sai st do cc acid bay hi trong qu trnh chng ct. Tin hnh: Chng ct bia: ly 100ml bia cho vo bnh ct, b sung 50ml nc ct. Lp vo b ct cn. Bp bp ln bt u chng ct cn. Khi thu c khong 90ml dch ct th ngng chng ct. Lm ngui phn dch sau khi chng ct ri cho vo bnh nh mc nh mc chnh xc ln 100ml. Khuy u dung dch sau khi nh mc, dng ph k xc nh t trng 20oC. Kt qu: T trng cn sau khi ln men: Mu : 10% cn. b. ln men: Ly dch ng cn li sau khi chng ct ui ht cn tin hnh nh mc 100ml. o dch ng bng Brix k 20oC. Ta c kt qu: Mu : oBr2 = 5o ln men:o

Mu :

Brix 0 oBrix 2 12 5 x100 = x100 = 58,33 % o 12 Brix 0

Kt Lun

Nng cn:

Nhm 6|08DSH2

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Bo co: TH CNLMTT


S liu khng chnh xc do cn k. Cn k dng o ru em s dng o bia m lng cn trong bia l qu thp so vi lng cn c trong ru v chnh lch ca vch mc b rt ngn nn khng ph hp o bia. ln men: Lng ng cn li sau qu trnh ln men l 5o Brix cao so vi tiu chun lng ng cn li sau qu trnh ln men l 2 - 3o Brix. Do:-

Nm men ging trong t lnh qu lu lm gim kh nng hot ng. Nng lc ng ha ca malt l khng t tiu chun. Thi gian ln men ca qu trnh ln men bia l cha thi gian. S phn b khng ng u ca nm men trong dch. T l ln men ging qu cao.

-

Nhm 6|08DSH2

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Bo co: TH CNLMTT


Bi 2: SN XUT NC TNG LN MEN

X du hay nc tng (phng ng min Nam Vit Nam) l mt loi nc chm c sn xut bng cch ln men ht u tng, ng cc rang chn, nc v mui n. Nc chm ny, c ngun gc t Trung Quc, c s dng kh ph bin trong m thc chu ti khu vc ng v ng Nam , gn y cng xut hin trong mt s mn n ca m thc phng Ty. Tc nhn thy phn c th l enzyme do vi sinh vt tit ra, c th l acid nh HCl (nc tng ha gii). Gn y ngi ta pht hin ra nc tng ha gii bng HCl c ch nhiu 3-MCPD c kh nng gy ung th. V vy c xu hng quay tr v cng ngh truyn thng. Trin khai mt s quy trnh sn xut nc tng an ton v 3-MCPD vi gi thnh chp nhn c bng cch kt hp ln men v ha gii.

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Bo co: TH CNLMTT


Nguyn liu: - Bnh du

- Nm si Aspergillus oryzae (hm lng cht bo cng thp cng tt : 45% nn khng cn phi b sung thm

Cy ging bo t Aspergillus oryzae:

Cy ging khong 3.3g mc ln mi trng sau khi lm ngui. Tin hnh cy ging trong t cy vi iu kin v trng. Cn 3.3g ging t bnh ging xut hin bo t mu vng hoa cau cho vo ti nilong cha bnh du sau khi hp kh trng v lm ngui trnh hi nc ng t lm hng sinh khi nm, trnh b tp nhim. Sau tin hnh tri hn hp bnh du( c trn nc, hp chn thanh trng v c lm ngui) cng nm mc vo khay nha c kh trng bng cn v c lt giy bo v trng bn di. Ly giy bo y li pha trn b mt nhng vn m bo yu t thong kh. t khay ni kn gi tin hnh qu trnh ln men. Nhm 6|08DSH2 Trang 28

Bo co: TH CNLMTT Ln men:


Ln men nhit phng 30 - 32oC, thi gian 45 gi n khi thy xut hin bo t mu vng hoa cau. Quan st v nhn xt kt qu mc ca nm mc sau khi ln men : m 45%:

bn trong c cht si nm mc t do m 45% , c cht khng c xp (do lng nc qu t) lm si nm khng m xuyn c c cht. m 55%:

Nhm 6|08DSH2

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Bo co: TH CNLMTT -


B mt c cht xut hin bo t nm mc cha hon ton nhiu nhng bn trong c cht si nm mc an xen ton b do c cht c xp v m thch hp, lng nc trong c cht va phi cho nm pht trin.

-

Mt ngoi tng i t bo t do qu trnh thot hi nc lm gim m khng cho nm pht trin.

m 65%:

-

bn trong c cht si nm khng mc do m 65% qu cao v lng nc trong c cht qu nhiu lm mt thong kh. trn b mt c cht bo t nm mc mc dy, nhiu so vi 2 nng trn do m 65% cao nhng khi qu trnh thot hi nc lm gim m thch hp cho nm pht trin tt. => V vy m 55% l thch hp nht nm mc sinh bo t v tng hp

enzyme protease c hot tnh cao nht. Thu phn: m1= 216g, m2=220.63g Trang 30

+ m 45%: Nhm 6|08DSH2

Bo co: TH CNLMTT + m 55%: + m 65%: m1= 220.15g, m1= 220.23g,

GVHD: TS. Nguyn Hoi Hng m2=220.68g m2=223.69g

(tr 10g khi lng giy v 3.3g nm mc c) 45% 55%: 65%: 135.3 g 206.15g, 321g, 130.67g 205.62g 324.1g

Gi x l % lng nc hao ht: 45% 55% 65% x1 = 40.03% x1 = 49.92% x1 = 60.45% x2 = 38.64% x2= 49.79% x2= 61.03% m1= 220.15g, m2=220.68g

m thun li nht l m 55%: Chun b nc mui: V H2O mui = 1,2.(m1 + m2) 3

+ m 45%: + m 55%: + m 65%: V H2O mui = 1,2.

m1= 216g, m1= 220.15g, m1= 223.69g,

m2=220.63g m2=220.68g m2=220.23g

(216 + 220 .63 ) = 174 .65 ml 3 (220 .15 + 220 .68 ) = 176 .33 ml 3

V H2O mui

= 1,2.

Nhm 6|08DSH2

Trang 31

Bo co: TH CNLMTT V H2O mui = 1,2.

GVHD: TS. Nguyn Hoi Hng( 223 .69 + 220 .23 ) = 177 .57 ml 3

Bnh du c ln men c b sung nc mui NaCl va tnh cho vo 3 hp nha c y np tng ng 3 nng : 15%, 20%, 25% em i thy phn trong b iu nhit nhit 55oC/72h. Trch ly:

- Dung dch sau khi c thy phn nhit 55oC trong 72h. Tin hnh cn 100g mu vi mi nng trong cc thy tinh bit trc khi lng. - Trch ly dung dch bng phu thy tinh c lt giy lc vi 100ml nc ct. - D ung dch sau khi lc cho vo ng ong nh mc n 100ml. - Tin hnh phn tch cc ch tiu nh gi nc tng cho 3 dch lc thu c ti 3 nng : 15%, 20%, 25% Phn tch cc ch s:

Tnh nit tng s: Xc nh hm lng nit tng s trong dung dch ng bngphng php Kjeldahl. Cch tin hnh: Gm 3 giai on c th sau: Giai on v c ha mu: Lc u mu nc tng, ly 5ml nc tng bng Pipet sch cho vo bnh nh mc 100ml, nh mc bng nc ct cho ti vch, lc u. Ht 20ml dung dch pha long bng pipet cho vo bnh cu c nhnh, cho 2g xc tc vo v 5ml H2 SO4 m c, y np kn li 30 pht. Dng nt cao su c gn h thng sinh hn y ln bnh ph mu, t ln bp un ri dn lung kh CO2 v SO2 i qua dung dch NaOH c trnh gy nhim Nhm 6|08DSH2 Trang 32

Bo co: TH CNLMTT mi trng xung quanh.


Tin hnh un nh, sau tng nhit dn, nhng ch nhit un phi nh o hn 100 C. Trong qu trnh un, thy mu khng trng th ngng un, ngui cho thm 0,5g xc tc v 3ml H2SO4 m c vo v tip tc un. Tin hnh un cho n khi dung dch c mu xanh trong, mt trong bnh khng hon ton trong sch m c cn en th ngng un, ngui.-

Giai on chng ct mu: Dng pipet ht 20ml H2SO4 0,1N cho vo bnh tam gic (bnh hnh nn hay

elen) hng ca b ct m v nh t t 3 git ch th hn hp vo bnh tam gic. Nhng u di ng sinh hn ca b ct m ngp vo dung dch trong bnh tam gic trnh mt m. Cho mu v c ha vo bnh chng ct (bnh cu c nhnh), dng nc ct trng bnh cu cha mu v c ha nhiu ln cho n khi nc trng ht phn ng vi axit (th bng giy qu). Cho 5 git phenolphtalein 1% v 35ml dung dch NaOH 30%, trng nc ct cho sch kim phu. Nu dung dch trong bnh cha c mu hng m th tip tc thm 5-10ml dung dch NaOH 30% n khi dung dch c mu hng m. Thm nc ct n khong 2/3 th tch ca bnh v kha phiu li. Gi mt t nc ct trn phiu cao khong 2cm trnh NH3 bay ln. Tin hnh ct n khi bnh hng c khong 250ml th dng (th u ng sinh hn bng giy qu nu khng c phn ng kim th qu trnh ct kt thc). Nhm 6|08DSH2 Trang 33

Bo co: TH CNLMTT


H bnh hng xung ng sinh hn khng chm mt nc v dng nc ct ra sch u ng sinh hn cho chy vo bnh hng.

-

Giai on chun mu: Mu v c ha: Ly bnh hng (bnh tam gic) ra chun lng axit d trong bnh bng NaOH

0,1N nng chnh xc. Ht 5ml dung dch trong bnh tam gic em chun . Cho dung dch NaOH 0,1N vo Buret, nh mc ti vch 0. Nh t t dung dch NaOH 0,1N vo bnh tam gic n khi dung dch chuyn t mu tm sang mu xanh l m th dng chun . Kt qu thu: c tnh bng cng thc: Nt =( n1 n2 ) x0.0014 x100 x1000 = 2,8(V1 V2 ) (g/l) 5 x10

Trong : n1: S ml dung dch H2SO4 0.1N cho vo bnh cha n2: S ml dung dch NaOH 0.1N dng chun acid d 0.0014 S gam nito tng ng vi 1ml NaOH 0.1N 100 Dung tch bnh nh mc, ml 1000 h s i ra g/l 5 S ml mu ly ra v c ho mu 10 S ml pha long cho vo my ct Chnh lch kt qu hai ln xc nh song song khng c qu 0.25g/l Nhm 6|08DSH2 Trang 34

Bo co: TH CNLMTT Hm lng Nit tng s cc nng mui 15%:-


Vi VH2SO4 = 20ml v VNaOH = 8.4ml(n1 n2 ) x 0.0014 x100 x1000 = 2,8(20 8.4) = 32 .48 (g/l) 5 x10

Nt = 20%:-

Vi VH2SO4 = 20ml v VNaOH = 5.6ml(n1 n2 ) x0.0014 x100 x1000 = 2,8(20 5.6) = 40 .32 (g/l) 5 x10

Nt = 25%:-

Vi VH2SO4 = 20ml v VNaOH = 4.2ml( n1 n2 ) x0.0014 x100 x1000 = 2,8( 20 4.2) = 44 .24 (g/l) 5 x10

Nt =

Bng s liu tnh ton thu c: Hm lng Nng mui 15% 20% 25% 32.48 40.32 44.24 Hm lng Nito tng s (g/l)

Tnh Nit amin: Xc nh hm lng Nit amin bng phng php chun formol Ho cht: Trang 35

Nhm 6|08DSH2

Bo co: TH CNLMTT + Dung dch NaOH 0.05N v 0.1N


+Ch th hn hp: 5 th tch Bromothymol xanh 0.04% v 4 th tch Phenolphtalein 0.5% (trong cn) +Formol trung tnh 40%: 1ml Phenoltalein vo 50ml formol ri dng NaOH trung ho n hng nht Tin hnh: Ly 10ml nc tng cho vo bnh nh mc 250ml, thm nc ct vo nh mc chnh xc 250ml, lc u. dng pipet ly 10ml, 15 git ch th hn hp sau cho vo tng git NaOH 0.1N n khi dung dch c mu pht xanh. Cho tip 5ml formol trung tnh (un chuyn sang mu vng xanh), chun bng NaOH 0.05N n khi dung dch chuyn t mu vng sang mu tm. Tin hnh xc nh mu trng bng cch thay 10ml nc tng pha long bng 10ml nc ct.-

Kt qu thu c: c tnh bng cng thc: Namin=( n1 n 2 ) x0.0007 x 250 x1000 10 x10

(g/l)

Trong : n1, n2 th tch NaOH tiu tn khi chun mu trng v mu th nghim, ml 0.0007 s gam nito tng ng vi 1ml NaOH 0.05N 250 dung tch bnh mc, ml 1000 h s i ra g/l Nhm 6|08DSH2 Trang 36

Bo co: TH CNLMTT 10 th tch mu nguyn, ml


10 th tch mu pha long cho vo my ct Chnh lch kt qu gia hai ln xc nh song song khng c qu 0.25 g/l Hm lng Nito amin cc nng mui khc nhau: 15%: Vi VNaOH = 3ml Namin = 20%: Vi VNaOH = 2.5ml Namin = 25%: Vi VNaOH = 2.19ml Namin =(2.19 0) x 0.0007 x 250 x1000 = 3.8325 ( g / l ) 10 x10 ( 2.5 0) x 0.0007 x 250 x1000 = 4.375 ( g / l ) 10 x10 (3 0) x0.0007 x 250 x1000 = 5.25 ( g / l ) 10 x10

Bng s liu tnh ton hm lng Nit amin thu c: Nng mui Hm lng Nito formon(g/l) 15% 5.25 20% 4.375 25% 3.8325 Nc tng qua trch ly th thu c sn phm c cht lng hi khc bit so vi sn phm qua ch bin. Bi v, nc tng cha qua ch bin c mu nu m, mi c trng nng ca nc tng. Cn nc tng qua ch bin c: mu nu nht, mi c trng. Mu sc nc tng sau khi trch ly co mu hi nu n nu cnh gin m theo Nhm 6|08DSH2 Trang 37

Bo co: TH CNLMTT t l 15%, 20%, 25%.


So snh yu cu cht lng ca mu th nghim v tiu chun Vit Nam: Loi c bit 20 55 Loi 1 16 55 Loi 3 12 55 Mu th nghim 15% 20% 25% NaCl 32.48 16.16 NaCl 40.32 10.85 NaCl 44.24 8.66

Tn ch tiu m tng s m formon/m tng s Nhn xt:

T kt qu ca m tng s cho thy s liu khng ng tin cy nn khng th so snh vi ch tiu cht lng nc tng ca tiu chun Vit Nam. S liu khng ng tin cy l do mt trong nhng l do sau: Do qu trnh chng ct khng v c ha ht mu. Do qu trnh thao tc. Do nguyn liu khng m bo cht lng. Do hot lc ca nm mc Aspergillus oryzae yu. Do ha cht b h. Bi 3: LN MEN YOGHURT

-

Yaourt (sa chua) l lai sn phm c ch bin t sa, rt c a chung v gi tr dinh dng cao, d hp thu v c bit l tc dng ci thin h vi sinh vt c ch trong ng rut. Trn th trng hin nay, sn phm Yaourt rt a dng v chun loi, cu trc, mi v ca yaourt lun c cc nh sn xut thay i ph hp vi th hiu v thi quen s dng ca khch hng ti cc nc khc nhau. Nhm 6|08DSH2 Trang 38

Bo co: TH CNLMTT


Nguyn vt liu - Sa b ti ca Vinamilk trung bnh cha 3,5% cht bo v 3,4% protein, 4,8% lactose Sa bt gy 500g 2 H sa chua Vinamilk khng ng

- Trong th nghim s dng hai chng vi khun lactic l: + Lactobacillus casei shirota

+

Streptococcus thermophiles

Nhm 6|08DSH2

Trang 39

Bo co: TH CNLMTT


Dng c - Bp in B iu nhit Bnh tam gic Buret pH k Giy pH Nhit k

My o pH

Nhm 6|08DSH2

Trang 40

Bo co: TH CNLMTT Cc bc thc hin Chun b sa - Sa ti: cht kh = 7.4 % - Sa bt: Cht kh = 80% - Yu cu cht kh l 15% Pha nguyn liu s dng cho ln men: 100ml sa ti c cht kh la 7,4g B sung cht kh bt la : 15- 7.4 = 7.6g


Vy khi lng cn b sung c cht kh 15% l:7,6 100 = 9,5 g 80

Lng sa bt cn ly trong 1l sa ti: 9,5x10 = 95 g X l nhit

Thanh trng sa 90oC trong 10 pht nhm lai b VSV trong qu trnh trn v protein trong sa thay i cu trc d ng t hn.

Nhm 6|08DSH2

Trang 41

Bo co: TH CNLMTT


Quy trnh cng ngh: Sa ti v sa bt

X l sa s b ng ging thch nghing X l nhit (thanh trng 90OC/10p) Nhn ging Lm ngui n to ln men

Cy ging

nhit 35-37oC thi gian 4h

Sa chua

Xc nh pH, acid

Lm lnh nhanhPhn tch sn phm

acid

tch nc

pH

Nhm 6|08DSH2

Trang 42

Bo co: TH CNLMTT


Lm ngui

- Khi t nhit 37 oC th chun b phn phi sa vo cc ng nghim cy ging. - Mi nhm tin hnh vi 10 ng nghim, mi ng cha 10ml hn hp sa c x l nhit.

Cy ging: Nhm chun b cho qu trnh ln men

Nhn ging: - ng thch nghing - Mi trng: Sa gy hon nguyn hm lng cht rn khc bo 10-12g/100g tit trng 121OC, 15 min.

Nhm 6|08DSH2

Trang 43

Bo co: TH CNLMTT


Cy ging B tr th nghim cy ging vi t l % v lng ging cy vo theo bng sau: Ging Nhm Nhm 1 Nhm 2 Nhm 3 Nhm 4 Nhm 5 Nhm 6 Ln men: Lactobacterium casei shirota ( Y1) 2% = 0.2 ml 4% = 0,4ml 0% 0% 1% = 0.1ml 2% = 0.2ml

Streptococcus thermophilus ( YT) 0% 0% 2% = 0.2ml 4% = 0.4 ml 1% = 0.1ml 2% = 0.2ml

- Tin hnh ln men nhit phng (37oC) bng cch cy ging cho vo b iu nhit thng qua cc mc thi gian 0h, 2h, 4h, 6h v qua m, do thi gian ln men khong 0h v 2h cha sn phm c chua nh mong mun (thng phi ln men trong 4 gi) nn cn theo di bin thin chua ca qu trnh ln men. - Theo di pH ca dch ln men v hm lng acid lactic sinh ra Lm lnh nhanh:

- Khi pH t 4.3 th tin hnh lm lnh nhanh v 5 oC - Sau tin hnh xc nh cc ch tiu phn tch tch nc ca sn phm.

Nhm 6|08DSH2

Trang 44

Bo co: TH CNLMTT Cc ch s:


o pH - Cc ng nghim cha dung dch sau khi ln men vi cc mc thi gian 0h, 2h, 4h, 6h, qua m em i xc nh pH bng my o pH. - Tin hnh: Sau khi cy ging ta cho cc ng nghim vo b iu nhit. Ring i vi 2 ng nghim 0h ta tin hnh o pH v chun NaOH. Ly 10ml dung dch c trong ng nghim ln men cho vo cc thy tinh. Dng my pH o nc ct trc ri a vo o dch trong cc thy tinh thu kt qu. Cc ng nghim cn li canh ng thi gian o tng t ng 0h. Xc nh chua C nhiu n v tnh chua ca sa nh Soxhlet Henkel (oSH), Thorner (oT), Dornic (oD). Thng thng chua ca chun c nh ngha l s ml dung dch NaOH 0.1N dng trung ha acid ca 100ml dch sa. Sa thng c chua trung bnh l 1618oT ( Thorner). *Cch tin hnh: - Dng mt dung dch kim chun NaOH 0.1N trung ho ht cc acid trong 100ml sn phm, vi 3 git phenolphtalein lm ch th mu. - Do hm lng sa c nn b sung thm 10ml nc ct pha long dung dch tin hnh chun cho n khi dung dich sa i mu ng sang mu hng. - Tnh kt qu

Nhm 6|08DSH2

Trang 45

Bo co: TH CNLMTT


Kt qu c tnh theo cng thc: chua ( oT) = VNaOH*10 (10: th tch mu em chun ). Ta tin hnh mi mc thi gian vi 2 mu v thu c th tch NaOH, tnh trung bnh th tch NaOH thu c v em xc nh hm lng acid lactic sinh ra ti mi thi im.

Bng kt qu thu c khi o pH bng my v chua ca yahourt: ml NaOH dng chun 10ml sa chua Thi gian Nhm N1 N2 N3 0h N4 N5 N6 N1 N2 N3 2h N4 N5 N6 Nhm 6|08DSH2 T l cy ging Y1 2% Y1 4% YT 2% YT 4% Y1 1% + YT 1% Y1 2% + YT 2% Y1 2% Y1 4% YT 2% YT 4% Y1 1% + YT 1% Y1 2% + YT 2% Mu 1 3.3 3.1 2.9 2.3 2.5 2.8 3.1 3.0 2.9 2.9 2.4 3.0 Mu 2 3.3 3.1 2.7 2.5 2.53 3.0 3.2 2.9 2.8 2.5 2.4 3.0 Trung bnh 3.3 3.1 2.8 2.4 2.515 2.9 3.15 2.95 2.85 2.7 2.4 3.0 chua T 33 31 28 24 25.15 29 31.5 29.5 28.5 27 24 30 o pH bng my Mu 1 6.85 6.77 6.85 6.8 6.82 6.82 6.83 6.83 6.88 6.78 6.87 6.83 Mu 2 6.85 6.76 6.83 6.79 6.86 6.84 6.85 6.82 6.86 6.79 6.87 6.83 pHtb 6.85 6.765 6.84 6.795 6.84 6.83 6.84 6.825 6.87 6.785 6.87 6.83

Trang 46

Bo co: TH CNLMTT N1 N2 N3 4h N4 N5 N6 N1 N2 N3 6h N4 N5 N6 N1 Qua m N2 N3 N4 N5 N6 Y1 2% Y1 4% YT 2% YT 4% Y1 1% + YT 1% Y1 2% + YT 2% Y1 2% Y1 4% YT 2% YT 4% Y1 1% + YT 1% Y1 2% + YT 2% Y1 2% Y1 4% YT 2% YT 4% Y1 1% + YT 1% Y1 2% + YT 2% 3.2 2.9 2.9 2.9 2.2 2.8 2.8 3.2 3.67 3.95 3.1 3.45 4.5 4.9 4.5 5.5 4.5 4.7 3.2 3.0 3.0 2.5 2.5 2.8 2.75 2.9 3.65 3.6 3.0 3.7 4.7 4.8 4.8 5.8 5.5 4.7 3.2 2.95 2.95 2.7 2.35 2.8 2.775 3.05 3.66 3.775 3.05 3.575 4.6 4.85 4.65 5.65 5.0 4.7

GVHD: TS. Nguyn Hoi Hng 32 29.5 29.5 27 23.5 28 27.75 30.5 36.6 37.75 30.5 35.75 46 48.5 46.5 56.5 50 47 6.87 6.82 6.87 6.84 6.87 6.8 6.75 6.76 6.5 6.32 6.62 6.52 6.02 5.57 5.9 5.79 4.85 4.85 6.86 6.83 6.89 6.82 6.82 6.78 6.85 6.86 6.54 6.5 6.63 6.57 6.09 5.95 5.92 5.11 4.87 4.8 6.865 6.825 6.88 6.83 6.845 6.79 6.8 6.81 6.52 6.41 6.625 6.545 6.055 5.76 5.91 5.45 4.86 4.825

Phn tch cc ch tiu: chua: Bng kt qu thu c khi chun 10ml sa chua cc thi im: Nhm 6|08DSH2 Trang 47

Bo co: TH CNLMTT 0h Nhm 1 2 3 4 5 6 Trung bnh VNaOH (ml) 3.3 3.1 2.8 2.4 2.515 2.9 oT 33 31 28 24 25.1 5 29 28.3 6 (ml) 3.15 2.95 2.85 2.7 2.4 3.0 2h VNaOH oT 31.5 29.5 28.5 27 24 30 28.4 2 (ml) 3.2 2.95 2.95 2.7 2.35 2.8 4h VNaOH

GVHD: TS. Nguyn Hoi Hng 6h oT 32 29.5 29.5 27 23.5 28 28.2 5 VNaOH (ml) 2.775 3.05 3.66 3.775 3.05 3.575 oT 27.7 5 30.5 36.6 37.7 5 30.5 35.7 5 33.1 4 Qua m VNaOH (ml) 4.6 4.85 4.65 5.65 5.0 4.7 oT 46 48.5 46.5 56.5 50 47 49.08

S bin thin chua ca sa60 50 chua 40 30 20 10 0 0 2 4 Thi gian 6 8 10

chua ca sn phm tng dn l do nh hng ca thi gian ln men v cht lng sn phm, vi sinh vt phn hu ng lactose to ra lng acid lactic ngy cng tng lm chua tng. Nhn xt: - thi gian 0h mu cy Y1 (2%) cho chua yoghurt l cao nht 33% ngha l hm lng acid lactic sinh ra khi cy 2% L. casei shirota l cao nht. Nhm 6|08DSH2 Trang 48

Bo co: TH CNLMTT


- thi gian 2h mu cy Y1 (2%) cho chua yoghurt l cao nht 31.5% ngha l hm lng acid lactic sinh ra khi cy 2% L. casei shirota l cao nht - thi gian 4h mu cy Y1 (2%) cho chua yoghurt l cao nht 32% ngha l hm lng acid lactic sinh ra khi cy 2% L. casei shirota l cao nht - thi gian 6h mu cy YT (4%) cho chua yoghurt l cao nht 37.75% ngha l hm lng acid lactic sinh ra khi cy 4% Streptococcus thermophilus l cao nht. - Khi qua m mu cy YT (4%) cho chua yoghurt l cao nht 56.5% ngha l hm lng acid lactic sinh ra khi cy 4% Streptococcus thermophilus l cao nht. - acid trong khong cho php : 0T= 75-140 T kt qu trn cho thy chua tng dn theo thi gian nhng c kt qu cao nht ta thy t l cy ging vo sa l 2% L. casei shirota v 2% Str.thermophillus thi gian ln men l qua m. Streptococcus thermophilus: chng khng pht trin 10oC, pht trin tt 4045oC. L. casei shirota: c th ln men nhiu loi ng nh ng glucose, ng ha c nhiu loi ng khc nh galactose, fructose, mannose. N c th pht trin trong khong nhit v pH rng, nhit ti thch trong khong 30-40 oC, pH ti thch 5.5 Do ln men cc ng nghim 37 oC ph hp cho L. casei shirota pht trin nn cc mu c acid tng cao c th do hot ng ca L. casei shirota mnh c ch mt phn hot ng Streptococcus thermophilus. Kt lun chung: S thay i ca acid khng ng u v c sai khc c th do s chnh lch kt qu ca qu trnh cy ging, lng vi khun cho vo nhiu hoc t hn t l th nghim S liu khng cho kt qua chnh xc Nhm 6|08DSH2 Trang 49

Bo co: TH CNLMTT pH:


Lng acid lactic sinh ra lm thay i pH khong 4.6- 4.7 nh hng n kh nng lm ng t casein, to cu trc gel st, min, gi nc ca sn phm. tt c th nghim, pH to thnh qu ln nn lm sa chua c tch nc khng t chun khi so vi sn phm yaghurt ca Vinamilk rt nhiu.

-

tch nc: nh gi bn hay kh nng gi nc ca gel.

Cch tin hnh:

+ Cn khi lng giy lc (mG) + Cn 10g sn phm sa ln men (m1) + em m1 vo my ht chn khng trong thi gian 6 pht, sau tin hnh i cnkhi lng cn li trn giy lc (m2). Tnh kt qu: Kt qu thu c tnh bng cng thc: tch nc =(mG + m0 ) m1 100 m0

+ Nng ging Y1 + KT (2%)Mu 1:

- mG1 = 1.49g ; m1 =6.08g tch nc =mG1 + m0 + m1 m0 100 = 1.49 + 10 6.08 100 = 54.1% 10

- mG2=0.78g; m2= 5.25gNhm 6|08DSH2 Trang 50

Bo co: TH CNLMTT(mG2 + m0 ) m2 m0 100 =

GVHD: TS. Nguyn Hoi Hng0.78 + 10 5.25 100 = 55.3% 10

tch nc = Mu 2:

- mG1 =0.67g; m1= 4,48g tch nc =(mG1 + m0 ) m1 m0 100 = 0.67 + 10 4.48 100 = 61.9% 10

- mG2= 0.95g; m2= 5.58g tch nc =(mG2 + m0 ) m2 m0 100 = 0.95 + 10 5.58 100 = 53.7% 10

+

tch nc trung bnh =

54 .1 + 55 .3 + 61 .9 + 53 .7 = 56 .25 % 4

Nng ging Y1 + KT (4%)

Mu 1:

- mG1= 0.92g; m1= 5.73g tch nc =(mG1 + m0 ) m1 m0 100 = 0.92 + 10 5.73 100 = 51.9% 10

- mG2= 1.05g; m2= 4.4g tch nc = Mu 2:(mG2 + m0 ) m2 m0 100 = 1.05 + 10 4.4 100 = 66.5% 10

Nhm 6|08DSH2

Trang 51

Bo co: TH CNLMTT


- mG1=1.11g ; m1=4.95g tch nc =(mG1 + m0 ) m1 m0 100 = 1.11 + 10 4.95 100 = 61.6% 10

- mG2= 1.12g; m2=5.58g tch nc =(mG2 + m0 ) m2 m0 100 = 1.12 + 10 5.58 100 = 55.4% 10

tch nc trung bnh =

51 .9 + 66 .5 + 61 .6 + 55 .4 = 58 .85 % 4

Nhn xt: Mu sa chua Vinamilk khng ng tch nc ca sn phm sa Vinamilk = 42.5% Kt qu tch nc 2% v 4% trong th nghim u cao hn so vi d tch nc trong sn phm sa chua ca Vinamilk. Sn phm c chty lng km nhiu so vi Vinamilk. Nguyn nhn c th l: -

Hm lng protein ca sa ti v sa bt lm th nghim khng t tiu chun m Kh nng ln men ca cc ging vi khun b gim. S lng t bo nm men ho vo dch b cht mt phn Khng c m c in kin ln men Nhit b nh hng Kt lun chung: Nhng kt qu th nghim trn khng c chinh xc v tin cy

protein c vai tr rt quan trng trong qu trnh to gel nht nc.

nn nhm ch a ra nhng nhn xt xoay quanh bi th nghim. Mun c c 1 kt qu chnh xc th cn phi c thi gian v cc ln lp li trn 1 th nghim, cc ln lp li cho kt qu trng nhau mi c th khng nh c.

Nhm 6|08DSH2

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