Www.ebo.Vn Quy Trinh San Xuat Nuoc Giai Khat Chanh Day Len Men

8/3/2019 Www.ebo.Vn Quy Trinh San Xuat Nuoc Giai Khat Chanh Day Len Men

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LI CM N

Qua hn 3 thng nghin cu lm ti Nghin cu quy trnh sn xu t thnghim nc gii kht chanh dy ln men n nay c hon thnh.

u tin em xin gi li cm n n cha m em, nhng ngi sinh ra v nui

dng em ln khn, cho em cuc sng ngy hm nay.

c bit em xin gi li cm n n ThS.Phan Th Nh, TS.Nguyn Anh Tun

tn tnh gip hng dn em hon thnh ti ny

Em chn thnh bit n cc thy, c gio trong khoa Ch Bin truyn t cho

em nhng kin thc qu bu trong thi gian qua. Xin cm n cc cn b cc Phng,

B mn: Cng Ngh Thc Phm, Cng Ngh Ch Bin, Ha Sinh - Vi Sinh, khoa

Ch Bin, trng i Hc Nha Trang to iu kin thun li cho em hon thnh

ti.

Em cng xin cm n cc anh ch kha trc, ban b ng vin, ng gp

kin gip em hon thnh ti ny.

Em xin chn thnh cm n!

Nha Trang, ngy 15 thng 6 nm 2009

Sinh vin thc hin

L Cnh Tun


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DANH MC CHVIT TT

NGK: Nc gii khtHSQT: H s quan trng

CCTL: im cha c trng lng

VSV: Vi sinh vt

TH: ng thch hp

pH TH: pH thch hp

TLMTH: T l men thch hp

tTH: Thi gian thch hp

TBCTL: im trung bnh c trng lng

h: gi

CLCQ: cht lng cm quan


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DANH SCH BNG

Trang

Bng 1.1: Thnh phn ha hc ca tri chanh dy cho 100g dch ......................... 8Bng 2.1: Bng im v mi ca sn phm NGK ln men t chanh dy...............21

Bng 2.2: Bng im v v ca sn phm NGK ln men t chanh dy..................22

Bng 2.3: Bng im trong, mu sc ca NGK ln men t chanh dy....................22

Bng 2.4: Bng cc ch tiu VSV ca sn phm ung c ru thp.............25

Bng 3.1: Lng dch p thu c mi mu ......................................................34

Bng 3.2: Bng kim nghim cm quan dch p chanh dy...................................35

Bng 3.3: Hm lng ng tng cc mu........................................................37

Bng 3.4: Kt qu xc nh nng cht kh sau khi pha long...........................38

Bng 3.5: Kt qu xc nh pH sau khi pha long.................................................39

Bng 3.6: Bng im c trng lng sau khi pha long dch ................................39

Bng 3.7: Bng im c trng lng khi xc nh hm lng ng thch hp....40

Bng 3.8: Bng im c trng lng khi xc nh pH ln men thch hp..............42

Bng 3.9: Bng im c trng lng khi xc nh t l nm men b sung............45

Bng 3.10: Bng im c trng lng khi xc nh thi gian ln men .................. 47

Bng 3.11: Bng im cm quan iu v sn phm...............................................49

Bng 3.12: Hoch ton chi ph thnh phm...........................................................52

Bng 3.13: Bng im c trng lng ca sn phm NGK ln men t dch qu

chanh dy ............................................................................................................. 53


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DANH SCH HNH

Trang

Hnh 1.1: Cy chanh dy ...................................................................................... 6Hnh 1.2: Hoa chanh dy ...................................................................................... 6

Hnh 1.3: Qa chanh dy ...................................................................................... 7

Hnh 1.4: S ln men ethanol...........................................................................11

Hnh 2.1: S quy trnh d kin ch bin th nghim........................................23

Hnh 2.2: S b tr th nghim xc nh lng enzym pectinaza thch hp.......26

Hnh 2.3. S b tr th nghim long dch qu ..................................................27

Hnh 2.4: S b tr th nghim xc nh hm lng ng thch hp choqu trnh ln men.................................................................................................29

Hnh 2.5: S b tr th nghim xc nh pH thch hp cho qu trnh ln men ... 30

Hnh 2.6: S b tr th nghim xc nh t l nm men b sung thch hp cho

qu trnh ln men.................................................................................................31

Hnh 2.7: S b tr th nghim xc nh thi gian ln men thch hp................32

Hnh 2.8: S b tr th nghim iu v sn phm ..............................................33

Hnh 3.1: Biu th hin snh hng ca enzyme pectinase n

lng dch p .......................................................................................................34

Hnh 3.2: Biu th hin snh hng ca enzyme pectinaza n hm lng

ng..................................................................................................................37

Hnh 3.3: nh hng ca hm lng ng ban u n ru trong

qu trnh ln men..................................................................................................40

Hnh 3.4: S bin i ca hm lng ng trong qu trnh ln men ................... 41

Hnh 3.5: nh hng ca pH n ru trong qu trnh ln men....................... 43

Hnh 3.6: nh hng ca pH n s bin i hm lng ng trong

qu trnh ln men..................................................................................................43

Hnh 3.7: nh hng ca pH n s bin axit tng trong qu trnh ln men .... 44

Hnh 3.8: nh hng ca lng nm men b sung n qu qu trnh to ru.....45

Hnh 3.9: nh hng ca lng nm men b sung n hm lng ng cn li 46


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Hnh 3.10: nh hng ca thi gian ln men n qu trnh hnh thnh ru ........47

Hnh 3.11: nh hng ca thi gian ln men n lng ng cn li................48

Hnh 3.12: Biu th hin im cm quan c trng lng ca th nghim

iu v ..................................................................................................................49

Hnh 3.13: S quy trnh hon thin sn xut th nghim nc gii kht

ln men t dch chanh dy .................................................................................. 50

Hnh 3.15: Sn phm nc gii kht ln men dch chanh dy ...............................53


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MC LC

Trang

LI CM N ...................................................................................................... i

DANH MC CHVIT TT ............................................................................ ii

DANH SCH BNG...........................................................................................iii

DANH SCH HNH............................................................................................iv

MC LC ...........................................................................................................vi

MU ............................................................................................................. 1

Chng I: TNG QUAN ..................................................................................... 3

1.1. Tnh hnh nghin cu nc gii kht v nc gii kht ln men.....................3

1.1.1. Tnh hnh nghin cu trn th gii ........................................................... 3

1.1.2. Tnh hnh nghin cu trong nc .............................................................4

1.2. Gii thiu v chanh dy ................................................................................. 5

1.2.1. Ngun gc v c im............................................................................5

1.2.2. Thnh phn ha hc v vai tr ca chanh dy ..........................................8

1.3. Tng quan v qu trnh ln men.....................................................................9

1.3.1. Tc nhn ln men.....................................................................................10

1.3.2. Cch ca qu trnh ln men ................................................................... 10

1.3.3. ng hc ca qu trnh ln men..............................................................12

1.3.4. Cc yu tnh hng n qu trnh ln men............................................12

1.3.5. Nhng k thut p dng chung cho ln men.............................................14

1.3.6. Cc sn phm ph to thnh trong qu trnh ln men................................ 15

1.3.7. Cc vi khun c hi cho qu trnh ln men ............................................... 15

Chng II: I TNG V PHNG PHP NGHIN CU ......................... 17

2.1. i tng nghin cu .................................................................................... 172.1.1. Nguyn liu chnh....................................................................................17

2.1.2. Nguyn liu ph .......................................................................................17

2.1.3. Ha cht, thit b v dng c s dng nghin cu................................19

2.2. Ni dung nghin cu ..................................................................................... 20


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2.3. Cc phng php nghin cu.........................................................................20

2.3.1. Phng php vi sinh vt ..........................................................................20

2.3.2. Phng php ho hc ..............................................................................20

2.3.3. Phng php phn tch cm quan.............................................................21

2.3.4. xut quy trnh d kin sn xut nc gii kht ln men t dch chanh

dy.....................................................................................................................23

2.4. B tr th nghim............................................................................................26

2.4.1. Xc nh lng emzyme pectinaza b sung thch hp..............................26

2.4.2. Xc nh lng nc pha long dch ln men...........................................27

2.4.3. Xc nh lng ng b sung, pH ln men t l nm men

b sung, v thi gian thch hp cho qu trnh ln men ......................................28

2.4.4. B tr th nghim iu v sn phm ..........................................................33

2.5. Phng php s l s liu..............................................................................33

Chng 3: KT QU NGHIN CU V THO LUN ................................... 34

3.1. Kt qu xc nh lng enzyme pectinase b sung thch hp.........................34

3.1.1. Kt qu xc nh lng dch thu c......................................................34

3.1.2. Kt qu xc nh hm lng ng..........................................................37

3.2. Kt qu xc nh lng nc b sung vo dch qu .......................................383.3. Kt qu xc nh hm lng ng ln men thch hp. ................................. 40

3.4. Kt qu xc nh pH thch hp cho qu trnh ln men....................................42

3.5. Kt qu xc nh t l nm men b sung thch hp cho qu trnh ln men .....45

3.6. Kt qu xc nh thi gian ln men thch hp. ...............................................47

3.7. Kt qu th nghim iu v .............................................................................49

3.8. S hon thin quy trnh sn xut th nghim sn phm nc

gii kht ln men t dch qu chanh dy. ..............................................................503.9. Sb tnh ton gi thnh sn phm trong phng th nghim .......................... 52

Chng IV: KIN NGH V XUT KIN ..............................................54

TI LIU THAM KHO ...................................................................................56

PH LC.............................................................................................................


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MU

Tri cy l mt loi thc phm rt tt cho sc khe con ngi. N cung cpnhiu dinh dng cho cth, c bit l cc loi vitamin. Tri cy chn hi n ngay

th rt tt v n cn gi nguyn vn cc cht dinh dng c trong qu. Nc ta l

mt nc nhit i gi ma nn thch hp cho vic trng cy n tri, a dng v

phong ph v chng loi.

Tri cy li c tnh ma v, kh bo qun lu di, d b dp nt, kh vn chuyn.

V th m ngi ta cn tm ra cc phng php ch bin khc nhau to ra sn

phm mi nhm tng thi gian bo qun, tng gi tr cho sn phm. V p ng

nhu cu ngy cng a dng ca con ngi.

Hin nay trn th trng cc loi tri cy c ch bin cc dng nh: Phi

kh, sy, ngm nc ng, lm ko, bnh, mt, nc gii kht, sn xut ru

Nhng vic ch bin tri cy to ra sn phm nc gii kht ln men c cn

thp th cn rt t.

Nc gii kht ln men t chanh dy l mt sn phm hon ton mang tnh t

nhin, khng s dng ha cht bo qun, khng mu thc phm, ph hp vi xu

hng tiu dng hin i. y l sn phm giu cht dinh dng, rt tt cho sc

khe nu ung iu . Rt thch hp cho ngi tiu dng c bit l gii tr. Ph

hp cho c ngi gi v ph n.

T nhng tng trn, c sng ca khoa Ch Bin, b mn Cng Ngh

Thc Phm, ThS. Phan Th Nh TS. Nguyn Anh Tun em nghin cu v thc

hin ti Nghin cu quy trnh sn xut thnghim nc gii kht chanh dy

ln men.

Mc ch ca ti- Xy dng quy trnh ch bin th nghim nc gii kht ln men dch chanh

dy.

- Xc nh hm lng ng, pH, t l nm men b sung, thi gian ln men .


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ngha khoa hc v ngha thc tin

- L cscho vic p dng vo vic nghin cu sn xut cc sn phm nc

gii kht ln men t nhiu loi tri cy khc.

- Thnh cng ca ti s ra c cc thng s thch hp cho quy trnh sn

xut, nhm p dng vo sn xut vi quy m cng nghip, to ra sn phm mi, lm

a dng ha sn phm ung.

- Tn dng ngun nguyn liu di do m thin nhin ban tng cho t

nc Vit Nam, to ngun thu nhp n nh cho ngi dn.

- Trong qu trnh hc tp, tm hiu v nghin cu thc hin ti ny ti

c gng nhiu. Song, do trnh hiu bit cn hn ch, mt siu kin khng cho

php v trong qu trnh lm th nghim khng trnh khi thiu st. V vy, ti rt

mong c s xem xt, gp ca thy c v bn b.

Ti xin chn thnh cm n!


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Chng I: TNG QUAN

1.1. Tnh hnh nghin cu NGKv NGK ln men [11]Nc gii kht l loi ung ng vai tr rt quan trng i vi i sng con

ngi, ngoi vic cung cp cho con ngi mt lng nc ng k n cn b sung

cho c th mt lng ln cc cht dinh dng, cc loi mui khong, cung cp

ngun nng lng ln cho c th. V vy nc gii kht tr thnh nhu cu tt yu

khng th thiu c i vi cuc sng ca con ngi.

1.1.1. Tnh hnh sn xut NGK trn th gii

Ngnh sn xut NGK ang pht trin vi tc rt nhanh c v chng loi v s

lng, nhanh chng chim lnh v c th trng chp nhn trong sut th k XX.

Trong s phi kn cc hng sn xut nc gii kht ni ting nh: Cocacola,

Pepsicola, Nestle vi mt hng truyn thng l loi NGK pha ch t: ng,

hng liu, mu, CO2 v mt s loi ho cht khc.

Ngy nay, khi iu kin sng ca con ngi ngy cng c nng cao th nhu

cu s dng NGK ngy cng tng v ang tng bc chuyn dn t loi NGK pha

ch truyn thng sang s dng loi NGK c cha cc cht dinh dng nh cc loi:

axit amin, vitamin, mui khong c sn xut t cc loi tri cy. y c coi

l mt hng chin lc ch yu ca th k XXI, nn nhiu quc gia nh: M, H

Lan, c, Nht, Hn Quc, c, Thi Lan, Trung Quc v ang tp trung

nghin cu v sn xut c nhiu loi NGK t cc loi tri cy nh: Cam, da,

xoi, xri, i, to, l, du, m, nho, vi c cht lng rt cao ph hp vi nhu cu

ngy cng cao ca khch hng.

Theo don ca cc nh chin lc trong cc loi NGK c sn xut t tri

cy th loi NGK ln men c nh gi l mt hng mnh trong tng lai v rtph hp vi th h tr v y l sn phm c nh gi c gi tr dinh dng cao

nhqu trnh ln men ca vi sinh vt.

Cho n nay c mt s sn phm t tri cy nh: Bluebird, Treetop ... l cc

sn phm khng cn ca Florida (M) c sn xut t 100% dch tri nho, to m


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thnh phn c nhiu loi vitamin, mui khong, ng khong 15-18% ng

trong hp kim loi c dung tch 160-180ml. Mt s sn phm c lng cn thp

(6%V) mang nhn hiu: Arbor Mist (M) c sn xut t ru vang: Nho, du,

o... C hm lng ng t 12-15% v nhiu loi vitamin, mui khong khc

v ang c bn trn th trng Vit Nam, c ngi tiu dng nh gi cao nh:

Ru vang chanh dy

Schennebly Redlands Winery l mt trong nhng cng ty sn xut ru ni

ting M. H sn xut nhiu chng loi khc nhau nh ru v qu xoi, vi, i,

kh trong ru t qu chanh dy chim s lng ln nht. y l loi ru

rt c bit, n c kh nng lu v rt lu sau khi ung, khng ging nh cc loi

ru m chng ta tng thng thc. Ngoi v ngt n cn c v cht v hng

thm tht c trng.

1.1.2. Tnh hnh sn xut NGK trong nc [11]

Vit Nam c kh hu nng v kh, nn nhu cu s dng nc NGK rt ln, mc

d cho n nay c mt s cng ty nc ngoi c cp giy php u t v sn

xut NGK t tri cy ti Vit Nam, song mc tiu th bnh qun ca ngi Vit

Nam mi cht 0,16 lt/ ngi nm (l qu thp so vi nhiu quc gia trong khu

vc), trong khi ngun nguyn liu sn xut NGK t tri cy Vit Nam li vcng phong ph, a dng, hon ton c thp ng c cc yu cu v nguyn

liu sn xut n nh lu di li ang c nguy cb d tha do thiu cng ngh

ch bin ph hp. Nc ta c kh hu nhit i gi ma, c thin nhin u i v

ngun t ai mu m, tr ph, thun li cho vic trng v pht trin cc loi cy n

qu khc nhau nh nho, xoi, du, chanh dy V vy vic sn xut NGK hng v

tri cy t nhin rt thun li.

NGK ln men t dch tri cy khng qua chng ct, c cn thp c xem lloi nc ung t nhin c li cho sc khe v c cha nhiu cht dinh dng ca

tri cy. Hin nay trn th trng xut hin nhiu loi NGK vi nhiu hng v khc

nhau (nho, mn.). Tuy nhin, trn thc t th c rt t cc sn phm c hng liu

t nhin m ch l hng liu tng hp. Nhng loi nc ung ny hon ton khng


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c dinh dng m ch c mt t nng lng l ng, v nu s dng ng ha

hc li cn c hi i vi sc khe ngi tiu dng.

NGK ln men cha mt lng cn thp, nhiu ngi c th ung c k c

ph n v ngi gi, cn etylic trong NGK ln men t nhin rt tinh khit. Nc

gii kht ln men hng v chanh dy t nhin l mt loi NGK s dng nm men

saccharomyces ln men t dch chit tri chanh dy to ru etylic v CO2. Nh

khi ung ta c cm gic mt lnh nhCO2, v thm nng ca ru etylic v chanh

dy.

Vic nghin cu sn xut NGK ln men t tri cy l hon ton ph hp vi

xu th pht trin chung cu th gii v khu vc. Ti hy vng c ng gp mt

phn nh vo vic to ra loi sn phm mi c cht lng tt p ng c yu cu

ca th trng trong nc, tng bc ho nhp vi s pht trin chung ca ngnh

sn xut NGK trong khu vc v quc t.

1.2. Gii thiu v chanh dy

1.2.1. Ngun gc v c im

Chanh dy cn gi l lc tin, chum bao, chanh leo, mt mt, dy mt, m ly...

Tn khoa hc l: passiflora edulis. Thuc hpassifloraceae, b violales. Chi

passiflora hin c hn 400 loi, trong c khong 60 loi cho tri n c. Tnting Anh l: Passion Fruit.

Chanh dy l loi cy leo nhit i c ngun gc t nam Brazil, sau c

mang sang c v Chu u t th k XIX. L loi cy n tri c trin vng cc

nc ang pht trin. Vit Nam chanh dy c trng nhiu Lt, ng bng

Sng Cu Long (Cn th, An Giang, Kin Giang,).

Nc qu tri chanh dy c hng thm, v ngt v c hm lng axit khong

2%. Dch qu cha nhiu Vitamin A v C cng nhiu nguyn t vi lng c ch chotim mch Qu c v dy nn thun tin cho vic vn chuyn v bo qun lu.

a. Cy

Cy chanh dy rt d trng, a t kh ro, cn t nc, sng c c ni si

hoc t ct. Cy t trng thnh 12 thng tui, c th di n 15m, cho thu


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hoch tt trong vng 5 6 nm. Chanh dy l loi cy leo bng tua cun n mc

pha i din l, c chiu di 20 40cm.

Hnh 1.1: Cy chanh dy

b. Hoa

Hoa n tnh, mc t nch l. Mi hoa mang 5 nh c vi 5 ch dnh nhau

thnh ng y v tch ri phn mang bao phn. Do hoa p nn c nhiu ni

trng lm cy cnh.

Hoa chanh dy c tc dng an thn nh v c kh nng "ru" ng. Hoa chanh dy

v ang c nhiu nc dng iu tr cho nhng tr em d b kch ng hoc

c vn bt n v thn kinh, cha bnh hen suyn, ri lon tiu ha, chng mt

ng, v cc kh chu ca hi chng tin mn kinh.

Hnh 1.2: Hoa chanh dy

c. Qu

Tri chanh dy hnh cu hoc bu dc, kch thc 4,5 7cm, mu tm sm hay

vng chanh, t rng khi chn, v qu trn lng bng. V qu mng cng, trung b


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mu xanh, ni qu b mu trng. Tri mang nhiu ht c cm mm, mi thm rt

quyn r, hp dn. Dch qut 40% so vi trng lng qu. Phn dch cha nhiu

axit ly ra thm ng c c v ch bin nc gii kht, ru hay mt... Chanh

dy c hm lng ng va phi (8,5g gluxit/100g), thp hn mt s loi tri cy

thng thng khc (trung bnh l 9-12g/100g), nhng phn ln lng ng ny l

fructose c ngt cao (so vi ng saccharoza), v vy chanh dy vn c v ngt.

Mc d n cn cha cc loi axit hu c, ch yu l axit citric (3,9g/100g, t chua

hn tri chanh). Ngoi ra, trong chanh dy cn c mt t l cht nht nh protein,

lipid, cc cht khong v cht vi lng nh st, photpho, km, magnesium, nhiu

loi vitamin c bit l vitamin C v nht l cht x. V nng lng cung cp,

chanh dy tng ng vi xai, xri, v magnesium, tng ng vi chui

Dch qu cho vo NGK, lm kem... th hng v tht thm mt. Qu c hai loi:

Hnh 1.3: Qa chanh dy

- Dng tri tm: C v tri mu tm n tm sm, tri nh. Cy c tua dy,

nhnh v gn l mu xanh. Dng ny ph bin vng c kh hu mt, nh Lt,

Ty Nguyn - Vit Nam v cho hng v tri ngon nht.

- Dng tri vng: V tri mu vng chanh, tri ln hn dng tri tm, cy ctua dy, nhnh v gn l ng tm. Hoa ln v c trng mu tm sm hn dng tri

tm, ng thi dy cng mc mnh hn. Dng ny chu nng, thch hp vi vng c

cao thp (0 800m) nhng bng Sng Cu Long.


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d. Thu hoch v bo qun chanh dy

Thu hoch chanh dy tt nht khi qu chn. Trong qu trnh thu hi nn ct

trnh nh hng n cy. Vi iu kin mt m nh Lm ng th qu chanh dy

c th bo qun 5-7 ngy. Nhng trong iu kin nng nhTP.HCM th tri

chanh dy ch bo qun c khong 4 ngy.

1.2.2. Thnh phn ha hc v vai tr ca chanh dy [11]

Qa chanh dy gm rt nhiu cht, c thnh phn dinh dng rt phong ph,

cung cp cho c th mt lng dinh dng ng k. nhng ni khc nhau th

thnh phn ha hc ca tri chanh dy l khc nhau.

Bng 1.1: Thnh phn ha hc ca tri chanh dy cho 100g dch

Thnh phn Hm lng

Nc 66 84%

Protein 0.7 1.5%

Cht bo 0.2 0.3%

Gluxit 14.5 32.4%

Khong 0.5 0.8%

X 0.6 0.8%

Ca 4 17mg

P 35 64mg

Fe 0.4 2.1mg

Vitamin C 30g

Vitamin A 700 2410 IU

Niacin 1.5 2.2mg

ng 8.5g Glucid/ 100g

Acit citric 3.9/100g


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Vai tr ca tri chanh dy

Qa chanh dy c tc dng cha bnh, k c l, thn, hoa. Trong y hc, c hoa,

l, tri v v tri chanh dy u c dng cha bnh. Nc p chanh dy, c

bit l l chanh dy, c cha cht alkaloids gip lm h huyt p, an thn, gim au,

v chng li tc ng ca cc cn co tht.

Chanh dy rt giu vitamin C. Vitamin C chnh l cht chng oxy ha v chng

vim nhim. Do c th gip chng ta gim cc triu chng hen suyn.

Chanh dy l loi qu c nhiu cht x, cht x rt tt cho sc khe, n c th

nga bnh tim mch vnh ngoi ra cn gi c lng cholesterol. Giu ng

cung cp nng lng cho c th. Chanh dy c v ngt v v chua nn ngi ta

thng dng nc p t qu lm nc gii kht v thanh nhit. Chanh dy c

cha thnh phn gy ng v rt tt th gin, nn ung chanh dy trc khi i ng

gic ng ca bn su hn.

Hoa chanh dy c tc dng an thn nh. Cc nh nghin cu trng i hc

Florida (M) pht hin ra rng chit xut ca v tri chanh dy vng c th

chng li cc t bo ung th nh vo 2 hot cht c ngun gc thc vt l

carotenoids v polyphenol. Tri chanh dy khng cha cholesterol, giu vitamin A

v vitamin C, l ngun cung cp kali v cht st di do, ngun cht x tuyt ho,v gip lm du cc cang b cng cng.

nhiu nc, ngi ta dng tri chanh dy ch bin thnh nhiu th bnh

ngt khc nhau, kt hp hoc khng kt hp vi cc loi tri cy khc lm kem,

yaourt... Cn nc ta, cch dng ph bin nht l nu vi nc ng v pha vi

lm nc ung gii kht. Chanh dy cng tht tuyt vi khi c trn chung

vi sa c. Hng thm c trng ca chanh dy cng v chua nh nh kt hp vi

v bo v ngt ca sa to thnh mt mn gii kht hn hp khng th no qun.1.3. Tng quan v qu trnh ln men [7]

Ln men l qu trnh trao i ccht di tc dng ca enzym tng ng gi l

cht xc tc sinh hc. Ty theo sn phm tch t sau qu trnh ln men m ngi ta


17/73


chia lm nhiu kiu ln men khc nhau. Tuy nhin, c hai hnh thc ln men l ln

men ym kh v ln men hiu kh.

Ln men NGK l qu trnh ln men ym kh vi s c mt ca nm men, chng

s chuyn ha ng ln men thnh etanol v 2CO .

1.3.1. Tc nhn ln men

Tc nhn chnh ca qu trnh ln men nc gii kht l nm men

Saccharomyces cerevisiae. Da vo c tnh ca qu trnh ln men m nm men

c chia lm 2 dng chnh:

- Nm men ni: Gy ra s ln men ni, ln men nhit cao t 20-28oC. Qu

trnh ln men nhanh, to thnh nhiu bt, do tc dng thot kh CO2 nhiu nn trong

thi gian ln men nm men ni trn mt hoc llng trong dch ln men v ch lng

xung y thnh mt lp xp khi qu trnh lm men kt thc.

- Nm men chm: Qu trnh ln men chm nhit 5-10oC, CO2 thot ra t

trong qu trnh ln men, nm men y thng ln men.

1.3.2. Cch ca qu trnh ln men [7]

ln men ngi ta cho vo mi trng mt lng t bo nm men nht nh.

Ty theo phng php ln men m cho vo lng nm men l khc nhau. Thng

khi ln men lng t bo nm men phi t ln hn mt trm triu t bo trong mtml dch ln men. V din tch b mt ca t bo nm men ln (do s lng t bo

nm men ln) nn kh nng hp th cc cht ca t bo nm men l rt ln. ng

ln men v cc cht dinh dng khc c trong mi trng ln men u tin c

hp th trn b mt nm men, sau c khuch tn vo trong t bo nm men.

Ru v CO2 c to thnh theo phn ng tng qut sau:

C6H12O6 + 2ADP + 3H 3PO4 = 2C2H5OH + 2CO2 + 2ATP + H2O

Nh vy s ln men chuyn ng thnh ru l mt dy qu trnh oxy ha khc enzyme trong t bo tham gia. Ru etylic to thnh khuch tn ra mi trng

ngoi qua mng t bo nm men. Ru ha tan v hn trong nc nn khuch tn

rt mnh vo trong mi trng. CO2 cng ha tan vo trong mi trng nhng

khng ln. V th CO2 sinh ra trong qu trnh ln men s khuch tn vo mi trng


18/73


v nhanh chng t c trng thi bo ha. Khi bo ha CO2 s bm vo t bo

nm men hnh thnh nhng bt kh. Bt kh sinh ra ngy cng nhiu v ln dn ln

to thnh ti kh ln, n thi im no c s chnh lch gia khi lng ring

ca mi trng v t bo nm men s ni ln trn b mt. Khi n b mt, do c s

thay i t ngt sc sng b mt nn chng b v lm cho bt kh CO2 thot ra

ngoi. Lc ny t bo nm men s b chm xung, qu trnh c din ra lin tc nn

t bo nm men chuyn t trng thi tnh sang trng thi ng, lm tng kh nng

tip xc gia t bo nm men v mi trng nn lm cho qu trnh trao i cht

din ra nhanh, mnh hn, nh th s lm gia tng qu trnh ln men. Kh CO2c

ch qu trnh ln men, nhng trong qu trnh thot kh CO2 lm tng kh nng ln

men ca nm men.

Hnh 1.4: S ln men ethanol

Ln men ethanol c chia lm hai thi k:

- Thi k cm ng: L thi ku hng phn ng xy ra theo chiu (1). Lc

ny sn phm l glyxerin. Bi v lc ny hm lng axetaldehyt (CH3CHO) cha c

nhiu nhn hydro ca alcoldehydrogenaza m hydro li chuyn n cho


19/73


photphoglyxeraldehyt to photphoglyxerin, sau photphoglyxerin b thy phn

gii phng axit photphoric v glyxerin.

- Thi k tnh: Lc ny lng axetaldehyt hnh thnh nhiu, nn hydro t

alcoldehydrogenaza li chuyn sang axetaldehyt (CH3CHO) theo chiu phn ng

(2), lc ny sn phm ch yu l ethanol v CO2.

1.3.3. ng hc ca qu trnh ln men [10], [7]

Tc ca qu trnh ln men c th theo di c bng cch theo di s thay

i ca hm lng ng trong dch ln men. Qu trnh ln men chia lm 3 thi k.

- Thi ku: Khong 60 h u k t lc cho t bo nm men tip xc vi dch

ln men. S ln men xy ra rt chm, ng ln men khng ng k.

- Thi k 2: y l thi k ln men chnh., chim khong 60 120 h sau thi k

u. S pht trin ca t bo nm men v s ln men sau mi gi ln men tng

nhanh ng k v t tr s cc i.

- Thi k cui: y l giai on ln men ph, qu trnh ln men din ra rt

chm. ng thi l thi kn nh, to mi, to v cho sn phm.

Thi k ln men chnh l thi k bin i su sc cc thnh phn trong dch ln

men. Chng nh hng n kt qu ca qu trnh ln men.

1.3.4. Cc yu tnh hng n qu trnh ln menTrong sn xut, ngoi vic la chn chng nm men ngi ta cn phi nghin

cu cc iu kin ph hp nht t c hiu sut ln men cao. Cc yu tnh

hng n qu trnh ln men gm:

a. nh hng ca nng ng

Nm men ch c kh nng ln men cc ng n gin c bit l maltose v

saccharose. Trong dch len men ngoi ng ra, phi b sung thm mt s thc n

cn thit cho nm men nh cc mui amn, cc mui photphat v m nh ur.Nng ng thch hp t 18 - 22%, nu cao hn th kh nng ln men gim v

ngc li nu nng ng thp s khng to iu kin cho qu trnh ln men.

Thng nng ng t 30-35% th s ln men bnh ch.


20/73


b. nh hng ca nhit

Nhit c nh hng r rt n hot ng sng ca nm men, c thy l

nm men saccharomyces cerevisiae trong qu trnh ln men NGK. Ln men NGK

thch ng nhit 28-30oC, nhit 50oC tri v di 0OC th nm men

khng hot ng. Trong thc t ngi ta c th ln men nhit trong khong 4-

28oC ty theo yu cu ca ngi s dng.

c. nh hng ca pH mi trng

pH c ngha quan trng trong qu trnh ln men NGK. Nm men c th pht

trin trong mi trng pH t 2 - 8 nhng thch hp nht l t 4 - 4,5. Vi khun bt

u pht trin pH = 4,2 v cao hn, khi thp hn mc ny ch c nm men c th

pht trin c. V th trong qu trnh ln men nn iu chnh pH < 4. Khi pH = 8

th nm men pht trin rt km, ngc li vi khun pht trin rt mnh. pH = 3,8

nm men pht trin mnh th hu nh vi khun cha pht trin.

to pH thch hp trong mi trng nui cy nm men ngi ta thng b

sung vo mi trng ln men mt loi axit khng gy nh hng n hot ng ca

nm men. Thc t ngi ta hay dng axit citric iu chnh pH.

d. nh hng ca oxy

Oxy l thnh phn quan trng trong giai on pht trin sinh khi ca t bonm men. Tuy nhin n l nguyn nhn gy h hng sn phm trong cc cng on

k tip.

Ln men NGK l mt qu trnh ln men ym kh, nhng ln men trong giai on

u nht thit phi cho dch ln men tip xc vi oxy cho nm men sinh trng

v pht trin (tng sinh khi). Nhng oxy ch cn c t trong giai on u, khi dch

ln men t s lng t bo nm men, th ngn chn dch ln men tip xc vi

oxy nm men tin hnh qu trnh ln men chuyn ha ng thnh ru v CO2.e. nh hng ca nng ru v CO2 [10]

Ru v CO2 c tc dng km hm s sinh trng v kh nng ln men ca nm

men. S sinh trng ca nm men b chm li khi nng ru c trong mi

trng ln men l 1%, t 4-6% c nh hng xu. a s nm men ln men c


21/73


nng ru t 12-14%, ch c mt s t ln men nng ru t 17 20%. Kh

CO2c ch s ln men nhng vic thot kh CO2 li c tc dng tt cho qu trnh

ln men. Khi thot kh CO2 s lm cho mi trng ln men lun chuyn ng, ko

di trng thi llng ca t bo nm men nn lm tng qu trnh ln men.

f. nh hng ca s lng t bo nm men

S lng t bo nm men cho vo dch ln men nh hng rt ln n qu trnh

ln men. Nu s lng t bo nm men cho vo thch hp th qu trnh ln men

din ra tt v hiu sut thu hi cao, cht lng sn phm tt hn. Nu s lng t

bo nm men cho vo qu t th tc ln men chm. Sinh khi t bo nm men

qu nhiu th mi trng dch ln men khng cho nm men pht trin, t bo

nm men s cht dn, sn phm sinh ra mi v l, ph mt lng nm men ng k.

1.3.5. Nhng k thut p dng chung cho ln men [7], [10]

a. Chng oxy ha nc qu

Nu dch qu tip xc vi oxy ca khng kh s gy ra hin tng oxy ha dch

ln men nh hng n cht lng ca sn phm. V th cn c nhng bin php

phng chng. Sau y l mt s bin php phng chng:

- Khng lm dp nt qu trong sut qu trnh thu hi, vn chuyn.

- Cn c cng on phn loi, la chn nguyn liu khi a vo sn xut.- Va tch dch xong cn tin hnh ln men ngay.

- Dng nhng bin php l ha hn ch oxy ha.

- Cha dch trong thit b c CO2 thay cho O2

- X l nhit cng l mt bin php chng oxy ha c hiu qu.

b. Theo di qu trnh ln men

K thut theo di qu trnh ln men l cng vic rt quan trng, nu khng c

theo di chu o c th dn n hng c m ln men hoc sn phm s km chtlng. Nn phi to iu kin cho qu trnh ln men din ra nhanh. trnh cho vi

sinh vt pht trin lm hng sn phm. Theo di qu trnh ln men bng cch theo

di lng bt kh bay ln, nu thy tc ln men chm th cn b sung thm nm

men ngay.


22/73


1.3.6. Cc sn phm ph to thnh trong qu trnh ln men

Khi ln men bn cnh cc sn phm chnh l ru etylic v kh CO2 cn c

nhiu sn phm ph khc nh: axit acetic, glyxerin, acetaldehyt,

- Sto thnh glyxerin [4]

Trong iu kin bnh thng, khi pH ca mi trng t 4 5 th s ln men

c gii thch bng phng trnh tng qut sau:

C6H12O6 pH = 4 - 5 CH3CHO + CO2 + C3H8O3 (glyxerin)

Cn khi pH > 7 th sn phm to ra nh sau:

C6H12O6 pH > 7 CH3COOH + O2 + C3H8O3 + C2H5OH

- Sto thnh acid hu c

Trong qu trnh ln men ru lun to cc acid hu cbao gm: acetic, lactic,

citric, pyrovic v succinic nhng nhiu nht l acetic v lactic, axit acetic b mt

hydro v ngng t to thnh acid succinic. Ta c phng trnh tng qut sau:

- Sto thnh este

Cng vi s to thnh axit, acol, di tc dng ca ezym esteaza ca nm men,

cc axit v acol s tc dng vi nhau to thnh nhng este tng ng. c vit

di dng tng qut nh sau:

R1CH2OH + R2COOH R2COOCH2R1 + H2O

Ngoi ra trong qu trnh ln men cn to ra cc sn ph khc nh: aceton,

diacetyl v 2,3 butanol.

1.3.7. Cc vi khun c hi cho qu trnh ln men

Dch ln men khng ch l mi trng dinh dng cho nm men m cn c cc

vi sinh vt khc. Cc vi sinh vt nu ln vo dch ln men chng s bin ng

thnh cc sn phm khc v th lm gim hiu sut ln men ru. Trong qu trnh

ln men ru thng gp cc loi vi sinh vt sau:

a. Vi khun lactic

y l loi vi khun ym kh, chng gm 2 loi: Lactic in hnh v lactic

khng in hnh.


23/73


vi khun acetic

vi khun lactic

Lactic in hnh s bin ng thnh sn phm duy nht l axit lactic

C6H12O6 2CH3CHOHCOOH + 18 kcal

Vi khun lactic khng in hnh s s dng ng v to ra axit lactic, ngoi ra

cn to ra mt lng ng k alcol, axit acetic, cacbonic v aceton. Cc sn phm

ny to ra khng n nh. Lactic in hnh c nhit ti u trong khong 49-51oC,

cn lactic khng in hnh c nhit ti u trong khong 37 - 38oC.

b. Vi khun acetic

Vi khun acetic l loi vi khun ho kh khng to thnh bo t, c nhit ti

u trong khong 20-35oC, ti a 42oC chng pht trin tt trong mi trng c alcol

thp, oxy ha alcol thnh axit acetic.

C2H5OH + O2 CH3COOH + H2O + 116 kcal.

Trong mi trng khng c acol, vi khun acetic s oxy ha ng thnh acid

gluconic.

Cc vi khun acetic t c kh nng pht trin trong iu kin ln men ru v vi

khun ny rt hiu kh.

c. Vi khun butylic v cc vi sinh vt khc

Cc vi sinh vt loi ny khng pht trin trong qu trnh ln men v pH ti thch

ca chng nm trong mi trng trung tnh hoc kim yu. V th nhim khun ch

yu trong qu trnh ln men l vi khun lactic.


24/73


Chng II: I TNG V PHNG PHP NGHIN CU

2.1. i tng nghin cu

2.1.1. Nguyn liu chnhS dng qu chanh dy lm nguyn liu chnh c mua chVnh Hi, ly t

tnh Lm ng. Dng qu mu tm t chn k thut: C Mu tm xanh;

Trng thi: hnh bu dc, cn nguyn vn khng dp nt.

2.1.2. Nguyn liu ph

a. ng

Dng iu chnh Brix to iu kin thun li cho qu trnh ln men, v

dng iu chnh v ca sn phm sau ln men. S dng ng saccharose tinhluyn, dng ng ct trng tinh khit, c ng gi k ca cng ty ng Khnh

Ha.

- Yu cu v mt k thut: ng s dng l ng tinh luyn cao cp, ng

knh phi tun theo TCVN 1695-87, hm lng Saccaroza > 99,5%, hm lng m

< 0,05%, lng ng kh < 0,1%

- Tiu chun cm quan: Dng tinh th tng i ng u, khng vn cc,

khng m, khng tp cht l, v ngt, khng c v l no khc, khng mi l, tt ctinh thu trng tinh, ng nh, khi pha trong nc ct th dung dch trong sut.

b. Nm men

Nm men s dng l chng Saccharomyces Cerevisiae thuc chng nm men

ni, c gi trong ng nghim, nm men ang dng tim sinh trn mi trng

thch nghing.

Nm men c cung cp bi Vin Cng Ngh Sinh Hc TP - H Ni

Sau nm men c cy chuyn sang mi trng thch nghing v em itng sinh trong mi trng dch qu chanh dy.

- Chun b dch chanh dy: Dch chanh dy c Brix trong khong 10 12%,

pH = 4 sau em i thanh trng v lm ngui. Dch c ng trong bnh tam

gic 250ml, t ly t 1/3 1/2 dung tch ca bnh.


25/73


- Tin hnh tng sinh: Dng que cy ly mt khun lc cho vo dch chanh dy

chun b nh trn v khuy u, y kn bnh tam gic ngay sau khi cy. Cng

vic tng sinh c tin hnh bn ngn la n cn trnh tp nhim vi sinh vt l

sau khi cy nm men. Sau 24 30h th tin hnh ln men c.

c. Axit citric ( 876 OHC )

S dng dng tinh th, mu trng, tan v hn trong nc v to dung dch

trong sut.

Axit Citric c s dng lm gim pH cho dch ln men.

Yu cu i vi Axit Citric: Khng ln tp cht, hm lng axit xitric > 99%,

hm lng m < 0,3%.d. EnzymePectinaza

Pectinaza c tn thng mi lNovoferin 14, l nhm enzyme xc tc s phn

ct cc hp cht pectin (c phn t lng ln) thnh cc hp phn khc nhau c

phn t lng thp hn ccht ban u.

B sung enzymepectinaza vo tht qu chanh dy nhm mc ch: p dch c

d dng hn (p c nhiu dch), to ra nhiu ng hn cho dch p, lm cho

dch p trong

p h

n. Enzyme

pectinaza c cung c

p b

i vi

n Cng Ngh

Sinh

Hc - Thnh Ph H Ch Minh.

e. Na2CO3

S dng nhm mc ch to pH thch hp cho qu trnh ln men.

Na2CO3 c s dng dng ht, mu trng.

f. Nc

Nc c s dng trong ti nghin cu ca ti l nc ct c chng ct

ti phng th nghim Ha Sinh trng i Hc Nha Trang.


26/73


2.1.3. Ha cht, thit b v dng c sdng nghin cu

a. a im nghin cu

ti c tin hnh ti phng th nghim b mn: Cng Ngh Thc Phm,

Cng Ngh Ch Bin, phng Ha Sinh ,Vi Sinh Khoa Ch Bin Trng i

Hc Nha Trang.

b. Cc thit bc sdng lm ti

- My o pH meter - BASIC ( M) vi chnh xc 0.01.

- Khc x ko Brix ATGO 1E ( 0 32%)

- My p dch

- B chng ct cn n gin (phng ha sinh)

- Cn in t vi chnh xc 0.001g.

- My ng np

- Cn k

- Ni thanh trng

- Thit bn nhit

- Cc dng c, thit b cn thit trong phng th nghim

c. Ha cht sdng

Ha cht xc nh ng tng s (Theo phng php Bertrand):- Dung dch HCl m c.

- Dung dch NaOH 30%, 20%, 10%.

- Dung dch polyphenol 1% trong cn.

- Dung dch ch axetat 30%.

- Dung dch Feling A: 69.28g CuSO4 tinh th + nc ct va 1 lt.

- Dung dch Feling B:

34.6g kalinatritactrat +100g NaOH + nc ct va 1lt- Dung dch bertrand (Dung dch st (III) sunfat):

50g Fe2(SO4)3 + 200g H2SO4m c + nc ct va 1 lt.

- Dung dch KMnO4.


27/73


Ha cht xc nh ru

- Thuc th nitrocromic: 4.9g kalibicromat + 1000 ml axit nitric m c.

- Dung dch kali iodua 10%: 100g KI tinh th + nc ct va 1 lt.

- Dung dch natrihyposunfit 0.1N.

2.2. Ni dung nghin cu

Nghin cu cc thng s thch hp cho qu trnh ln men.

- Xc nh hm lng enzyme pectinaza thch hp cn b sung.

- Xc nh t l nc b sung thch hp.

- Xc nh hm lng ng thch hp cho qu trnh ln men.

- Xc nh pH thch hp cho qu trnh ln men.

- Xc nh t l men b sung thch cho qu trnh ln men.

- Xc nh thi gian ln men thch hp.

Xc nh t l syrup b sung thch hp cho th nghim iu v.

2.3. Phng php nghin cu

2.3.1. Phng php vi sinh vt

- Nhn ging nm men: Mi trng nhn ging l dch p tht qu c kh

t 100 120g/l, pH: 4,5 - 4,7

- Mi trng ln men l dch qu c kh t 160 220g/l, pH: 3.5 5.0.- Nm men c nui cy v ln men nhit 25- 27oC.

2.3.2. Cc phng php ho hc

- Xc nh hm lng ng tng s v ng kh bng phng php

Bertrand

- Xc nh hm lng axit tng s bng KOH 0,1N ch th l Phenolphtalein

- Xc nh hm lng cn bng phng php ha hc

- Xc nh pH bng pH meter - BASIC ( M)


28/73


2.3.3. Phng php phn tch cm quan [2]

Cht lng cm quan sn phm c nh gi bng phng php cm quan theo

tiu chun Vit Nam (TCVN 3215 79). Tiu chun ny s dng h s 20 im,

xy dng trn mt thang thng nht c 6 bc (T 05), v im 5 l im cao nht

cho mt ch tiu. Su bc nh gi c m tph lc 3.

i vi sn phm ung c cn ni chung v sn phm nc gii kht ln

men ni ring th cc ch tiu cm quan quan trng cn nh gi gm:

- trong v mu sc, mi, v

Di y l bng chun c xy dng tin hnh nh gi cht lng cm

quan ca sn phm NGK ln men t chanh dy. Da vo bng chun tin hnh

lp chon 5 thnh vin (lp 47TP3. kha 47) nh gi cm quan sn phm.

Khi nh gi cm quan cc ch tiu cm quan ca sn phm, 5 thnh vin tham

gia cho im, kt qu trnh by l trung bnh cng im ca cc kim nghim vin.

Sau y l bngnh gi v mi (Bng 2.1).

Bng 2.1: Bng im v mi ca sn phm NGK ln men t chanh dy

Bc nh

gi

CC

TL

HSQ

TCsnh gi

1 5Thm du, hi ha, c mi c trng ca chanh dy,

thong mi ru, to cm gic thch mnh.

2 4Mi thm nh, c trng cho sn phm, thm mi

ru v tng i hi ha, to cm gic thch.

3 3C mi thm ca chanh dy, mi cn cao, mi

khng c hi ha, kh nhn ra mi.

4 2

Sn phm cn mi thm ca chanh dy, mi ru

cao r rt, mi khng hi ha, thong mi l.

5 1 Sn phm c mi l r rt, nng, hng.

6 0

1.2

Sn phm c mi l kh chu ca sn phm hng.


29/73


Bng 2.2: Bng im vv ca sn phm NGK ln men tchanh dy

Bc

nh gi

CC

TL

HSQ

TCsnh gi

1 5

V ngt ca ng, ca ru, ca glyxerin, hi ha

vi v chua nh ca axit, v cht nh ca tanin, vm

ca mui khong. To thnh v m du, m ,

hu ko di.

2 4Sn phm c v hi ha, d chu, c trng, hu va

phi.

3 3Sn phm thiu v m , hi chua, hu yu, cho

cm gic khng thch.4 2 V chua ni tri, t ngt, ng.

5 1 V chua gt, ng mnh, khng ngt, v cht, c v l.

6 0

2.0

V chua rt gt, ng gt, cht gt, v l ca sn phm

hng.

Bng 2.3: Bng im trong, mu sc ca NGK ln men tchanh dy

Bc

nh gi

CC

TL

HSQ

T Csnh gi

1 5Sn phm trong, khng vy c, mu vng p,

hp dn, rt chy lng u.

2 4Sn phm trong, khng vn c, mu vng nht,

rt chy lng u.

3 3 Sn phm c mt cn llng, mu t c trng.

4 2 Sn phm hi c, mu khng c trng.

5 1Sn phm c, nhiu cn l lng, mu khng c

trng.

6 0

0.8

Sn phm vn c, mu bn, sn phm b hng.


30/73


2.3.4. Quy trnh dkin sn xut nc gii kht ln men tdch chanh dy

[7], [11]

Hnh 2.1: S quy trnh dkin chbin thnghim

Thanh trng

Chit chai(thy tinh 240ml)

Sn phm

ngNcNa2CO3

Phi ch

Ln men

Thanh trngNm menchm

X l sau ln men(lm trong, iu v)

t0 = 600C

T= 15 pht

t0 = 25 - 270C[] = 160 - 220g/lTLM = 1- 2.5%T = 48 - 84 h)

t0=60 - 620CT= 30pht

X l

Enzyme

pectinaza

p ly dch

Chanh dy

t0 = 400C

T= 60 pht

Pha long

Tng sinh


31/73


Thuyt minh quy trnh

Nguyn liu l mt trong nhng yu t quan trng quyt nh n cht lng sn

phm v th vic chn nguyn liu a vo sn xut l rt quan trng. Chanh dy

c mua chVnh Hi l qu c chn k thut mu tm, t cc ch tiu v

chn. Qu to khng dp nt, khi bi ra tht qu c mi thm mnh, mu vng

ti. Nguyn liu sau khi mua vem i x l: Ra sch bng vi nc chy

loi b cc tp cht bm trn qu v ng thi loi b mt phn vi sinh vt bm trn

qu. Sau ro v tin hnh bi ly cm. Qu trnh x l cn din ra

nhanh trnh hin tng oxy ha dch qu. Sau x l cn mang i b sung

enzyme pectinase v ngay nhit 400C trong 1h. nhm lm tng hiu sut p

dch, lm gim nht ca dch ln men, tng cht lng ca dch p c v mt ha

l v cm quan. V ha l hm lng ng trong dch nhiu hn do qu trnh thy

phn pectin to ng n. V cm quan th mu p, trong, ti hn so vi dich

qu ban u.

Sau khi tin hnh p ly dch qu v phi ch b sung ng, nc, cht

iu chnh chua (Na2CO3) tip theo l thanh trng. Thanh trng nhm dit mt

s vi sinh vt c hi cho qu trnh ln men. Tin hnh thanh trng 600C trong 15

pht v lm ngui.

Sau lm ngui cn b sung nm men ln men ngay trnh s pht trin ca

vi sinh vt c hi.

Sau ln men tin hnh lm trong v diu v sn phm nhm tao ra sn phm c

v hi ha v m bo v mt cm quan. Lm trong bng cch lng sau tin

hnh lc bng vi lc. iu v sn phm bng syrup ng. Syrup ng c lm

nh sau:

Nc v ng c phi trn vi t l 1/7 sau em un si trong 10 pht.

Sau tin hnh b sung axit citric theo t l nc/axit citric: 200/1(g/g) nhm

iu ha v v trnh hin tng li ng trong sn phm sau ny. Tip n ta un

si dch tip trong 10 pht ha tan hon ton cc thnh phn vo dch syrup. Sau


32/73


lm ngui n 600C v lc bng vi lc nhm loi b tp cht lm cho dich syrup

c sch hn v lm cho sn phm sau ny t cht lng tt hn. Tip tc lm

ngui n 200C v em i s dng nu cha s dng ngay th tt nht em bao qun

t lnh.

Thanh trng: Tin hnh thanh trng nhit 60-620C trong 30 pht tiu

dit mt phn vi sinh vt. Dit hon ton nm men duy tr sn phm ru

nht nh. Sau em i chit chai thy tinh 240ml v em i bo qun thnh

phm.

Theo quyt nh 46/2007/Q-BYT. Sn phm nc ung c cn phi m bo

cc ch tiu vi sinh vt (bng 2.4)

Bng 2.4: Bng cc chtiu VSV ca sn phm ung c ru thp

STT Ch tiuGii hn

ti a

1 Tng s VSV hiu kh (S khun lc trong 1ml sn phm) 10

2 E.Coli (S vi khun trong 1ml sn phm) 0

3 Streptococcus fecacalis 0

4 Cl.Perfringens (S vi khun trong 1ml sn phm) 0

5 Staphylococus aureus (S vi khun trong 1ml sn phm) 0

6 P. aeruginosa 0

Da vo bng ch tiu vi sinh vt ca sn phm do B Y T quy nh v nc

gii kht c cn thp nh trn th sn phm ang nghin cu c em i kim tra

vi sinh vt sau khi thanh trng sn phm. Sn phm i hi phi t tt c cc ch

tiu v vi sinh.a im kim tra VSV: Vin Nghin Cu v ng Dng Nha Trang, s 02

Hng Vng - Nha Trang - Khnh Ha.


33/73


2.4. B tr th nghim

2.4.1. Xc nh lng emzyme pectinaza b sung thch hp

Mt hp cht gluxit chim t l kh ln trong tht chanh dy l pectin. Hp

cht ny lm gim cht lng dch chanh dy. V vy, nng cao cht lng dch

qu ta tin hnh thy phn hp cht pectin bng enzyme pectinase. Cch tin hnh

nh sau: Lm th nghim vi 5 mu, mi mu 200ml tht qu, b sung enzyme

pectinaza dng dch vi cc th tch 0ml, 0.1ml, 0.2ml, 0.3ml, 0.4ml.

Th nghim c lp li 2 ln v ly gi tr trung bnh. nh gi sn phm sau

khi lm th nghim da theo cc ch tiu ha l v cm quan:

- Ha l: Xc nh lng dch p thu c, hiu sut ly dch. Xc nh hm

lng ng kh.

- Cm quan: V mu sc, trong, mc lng cn.

Hnh 2.2: S btr th nghim xc nh lng enzym pectinaza thch hp

Mu 1:0ml

Dch qu + Ht

Mu 20,1ml

Mu 30,2ml

Mu 40,4ml

Mu 30,3ml

B sung enzyme

nh gi chtlng dch lc

Lng enzyme thch hp

p dch

T0 = 400CT = 1h


34/73


2.4.2. Xc nh lng nc pha long dch ln men

Dch chanh dy sau khi p xong em i xc nh lng nc b sung vi cc t

l 30%, 40%, 50% so vi th tch dch qu, lm gim gi thnh sn phm m vn

m bo cht lng sn phm. Th nghim c tin hnh vi 200ml dch mi mu.

Hnh 2.3. S btr th nghim long dch qu

Dch p

Pha long

Mu 1

30%

Mu 1

40%

Mu 1

50%

Cm quanHm lngngpH

nh gi cht lngdch sau ha long

T l nc bsung thch hp

Tht qu(dch = ht)

B sungenzyme v


35/73


2.4.3. Xc nh lng ng b sung, pH, t l nm men b sung, v thi

gian thch hp cho qu trnh ln men

Qu trnh ln men l qu trnh chu nh hng ca nhiu yu t, trong nhng

yu t chnh nh hng trc tip n tin trnh ln men cng nh cht lng thnh

phm l: Nng ng, lng nm men b sung, pH v thi gian ln men. V

vy, xc nh c cc thng s thch hp sn xut th nghim sn phm NGK

chanh dy ln men t nhin cn phi tin hnh nghin cu snh hng ca cc

yu t n tin trnh ln men v cht lng thnh phm.

Cch tin hnh:

Qu chanh dy c x l, ly tht qu ri x l bng enzyme pectinase sau

p ly dch v thanh trng. Tip n em i iu chnh pH (bng Na2CO3), Brix

vi cc gi tr khc nhau theo yu cu ca th nghim. ng thi b sung nm men

vi cc lng khc nhau vo dch ri khuy cho nm men phn tn u. y np li

v tin hnh ln men nhit thng (25 270C).

Trong thi gian ln men tin hnh o cc thng s nh cn (bng phng

php ha hc), kh, axit ton phn. Sau 2 ngy k t lc ln men o ln u v

c sau 12 gio ln tip theo, lm tng t cho n khi kt thc qu trnh ln men.

Th nghim c tin hnh vi 200ml mi mu. Vi thi gian ln men l: 48h, 60h,72h, 84h; Ln men cc pH: 3.5, 4.0, 4.5, 5.0: T l nm men l: 1%, 1.5%, 2%,

2.5%; Nng cht kh l: 160g/l, 180g/l, 200g/l, 220g/l. Th nghim c lp li

2 ln.

Cc yu t cn xc nh trong qu trnh ln men

- Hm lng cn sinh ra: Sau 12 gighi nhn kt qu 1 ln.

- S thay i ng: Sau 12 gighi nhn kt qu 1 ln.

- axit tng s: Sau 12 gighi nhn kt qu 1 ln.


36/73


a. Xc nh hm lng ng thch hp cho qu trnh ln men

Hu ht dch qu t nhin khng lng cht kh tin trnh ln men din ra

tt. Do , trc khi ln men cn phi b sung thm ng iu chnh nng

cht kh ca dch ln men. Tin hnh b tr th nghim nh hnh 2.4.

Hnh 2.4: S btr th nghim xc nh hm lng ng thch hp cho qu

trnh ln men

Dch p pha long

(pH = 4)

B sung ng

Ln men (26 1oC, 72h)

Lm trong

Thanh trng(60 620C, 30 pht)

Xc nh

Hm lng ng thch hp (TH)

Cm quan ruLng ng cn li

B sung nm men vi t l 1.5%

Thanh trng (600C, 15 pht)

Mu 1160Brix

Mu 2200Brix

Mu 3220Brix

Mu 2180Brix


37/73


b. Xc nh pH thch hp cho qu trnh ln men

pH ca dch ln men c nh hng ln n qu trnh ln men v cht lng sn

phm. Nm men ch c th hot ng pH nht nh. Hu ht dch qu khng p

ng c pH ln men. V th ta tin hnh iu chnh pH cho dch ln men

Hnh 2.5: S btr th nghim xc nh pH thch hp cho qu trnh ln men

Dch p pha long

(TH)


Mu 1

pH=3.5

Mu 2

pH=4.0

Mu 3

pH= 5

Mu 3

pH=4.5

B sung nm men tl 1.5%

Ln men ym kh

Lm trong

Thanh trng (60-620C, 30 pht)

Xc nh

pH ln men thch hp (pH TH)


Acid sau len men


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c. Xc nh t l nm men b sung thch hp cho qu trnh ln men

Lng nm men nhiu hay t u c nh hng n qu trnh ln men. Nu t

th khng t bo nm men tin hnh ln men c hiu qu vi sinh vt d ln

tp, nu nhiu th khng ccht cho nm men hot ng to ra nghng

tnh cht dc trng cho sn phm to cc mi v l.

Hnh 2.6: S btr th nghim xc nh t l nm men bsung thch hp cho qu

trnh ln men


Dch p pha long

(TH, pH TH)

T l nm men b sung

Ln men ym kh

Lm trong

Thanh trng (60 620C, 30 pht)

Xc nh

T l men thch hp (TLMTH)


Mu 11%

Mu 21.5%

Mu 32.5%

Mu 32%


39/73


d. Xc nh thi gian ln men thch hp

Thi gian ln men l mt trong nhng yu t quyt nh cht lng sn phm.

Do vy, cn phi dng qu trnh ln men ng lc sn phm t yu cu. V th

ti tin hnh b tr th nghim xc nh thi gian ln men nh hnh 2.7.

Hnh 2.7: S btr th nghim xc nh thi gian ln men thch hp

Dch p pha long(TH, pH TH, TLMTH)

Mu 148h

Mu 260h

Mu 372h

B sung nm men vi TLMTH

Ln men ym kh

Mu 384h


Lm trong

Xc nh

Thi gian len men ti u (tTH)


Thanh trng (60 620C, 30 pht)


40/73


2.4.4. B tr th nghim iu v sn phm

Nhm to s hi ha v v cho sn phm do tin hnh th nghim iu v.

iu v ta b sung vo dch sau ln men 1 lng ng thch hp to ra sn phm

c gi tr cm quan v mi v. ng dng iu v sn phm l ng dng

syrup cbn 65oBx. Vi cc t l 5%, 6%, 7%, 8%. S b tr th nghim iu v

sn phm c th hin hnh 2.8. V ca sn phm c kim tra bng phng

php cm quan cho im.

Hnh 2.8: S btr th nghim iu v sn phm

2.5. Phng php xl s liu

y ti s dng phn mm Excel, v phng php nh gi cm quan x l

s liu. Kt qu l trung bnh cng ca cc ln th nghim.

6%

T l syrup bsung thch hp

nh i cm quan

iu v

Ln men 25 - 27oC

Dch p pha long

Phi ch

Thanh trng 60oC, 15 pht

Lm trong (lng, lc)

5% 8%7%


41/73


CHNG III: KT QU NGHIN CU V THO LUN

3.1. Kt qu xc nh lng enzyme pectinaza b sung thch hp

3.1.1. Kt qu xc nh lng dch trung bnh thu c

Lng dch p c s thay i khi tht qu chanh dy vi enzyme pectinaza.

Kt qu th nghim c trnh by bng 3.1 v hnh 3.1.

Bng 3.1: Lng dch p thu c mi mu

Lng enzym

pectinaza b sung (ml)0 0.1 0.2 0.3 0.4

Lng dch p (ml) 91.5 121 133 139 142

T (bng 3.1) ta c biu th hin snh hng ca enzyme pectinaza n

lng dch p (hnh 3.1).

91.5

121

133139 142

50

70

90

110

130

150

Lngd

chptrun

bn

h(ml)

0 0.1 0.2 0.3 0.4

Lng enzym pectinaza b sung (ml)

Hnh 3.1: Biu thhin snh hng ca enzyme pectinaza n lng dch p

Nhn xt v tho lun

Cc mu th nghim c 40oC bng thit bn nhit, thi gian l 1 gi.

Mu khng s dng enzyme pectinaza (mu i chng), dch chit trung bnh

thu c rt thp chc 91.5ml. Nh vy hiu sut p dch trung bnh thu c

khng cao (45.75%).


42/73


Mu b sung 0.1ml enzyme pectinaza th s ml dch tng ln ng k (121ml),

cao hn dch p ca mu i chng l 30.5ml. Hiu sut p dch l 60.5 % ln hn

so vi mu khng b sung enzyme.

Mu b sung 0.2ml enzyme th kt qu cho thy s ml dch p cng tng ln

133ml. Hiu sut p thu c l 66.5 %, tng so vi mu oml v mu 0.1.

Mu b sung 0.3ml enzyme pectinaza th s ml dch thu c l 139ml cng

tng so vi cc mu 0 ml, 0.1ml, 0.2ml nhng tng khng ng k so vi mu

0.2ml. Hiu sut p l 69,5%.

Mu b sung 0.4ml enzyme pectinaza th lng dch thu c l 142ml, hiu

sut p dch l 71% s ml dch p v hiu sut p c tng nhng rt t so vi mu

0.3ml. So vi mu i chng th s ml dch p thu c tng 50.5ml, hiu sut p

tng 25.25%.

Di y l bng kim nghim cm quan ca dch sau khi p cc mu:

Bng 3.2: Bng kim nghim cm quan dch p chanh dy

Tn muLng enzyme

pectinaza b sungc im cm quan

Mu 1Khng c enzyme

Mu ca dch p vng gch, c,

nhiu cn.Mu 2

0.1mlMu ca dch p vng, dch c do

c nhiu tp cht llng.

Mu 30.2ml

Mu ca dch p vng ti, cn hi

c.

Mu 40.3ml

Mu ca dch p vng ti, p,

trong, t c.

Mu 5 0.4ml Mu ca dch p vng hi m, ttrong, c t.

Nhn xt

Mu i chng c mu vng c li c cn v thim cm quan ca mu ny

thp.


43/73


Mu c b sung 0.1ml enzyme pectinaza c mu vng ti, trong v t cn hn

nhng vn cn c.

Mu b sung 0.2ml enzyme pectinaza dch c mu, trong p hn so vi mu

i chng v mu 2 (mu vng ti nhng vn cn c).

Cn vi mu b sung 0.3ml enzyme pectinaza c mu vng ti, p, trong, t

vy c.iu ny chng t khi b sung enzyme mu sc v trong tng theo

tng ca lng enzyme cho vo.

Mu b sung 0.4ml enzyme pectinaza c mu ca dch p khng c s thay i

nhiu so vi mu b sung 0.3ml, nhng trong gim xung.

Enzyme pectinaza khi 40oC trong 1 givi s c mt ca ion Ca2+ c trong

tht qu, enzyme ny hot ng thc y qu trnh thy phn cc lin kt glucozit v

cc lin kt ester ca pectin to cc phn t mch ngn hn v lm gim nht

lm cho qu trnh p tch dch c d dng hn. Nh vy khi b sung enzyme

pectinase vo p dch th ta thy c s bin i v lng dch p, mu sc,

trong. C th l hiu sut p tng theo tng ca lng enzyme cho vo v mu

sc, trong cng tng t. Nhng mu 5 th hiu sut p tng ln khng ng

k, trong gim.

Mu 3, 4 vi lng enzyme pectinaza bsung vo p dch l thy phn

200ml dch qucho hiu sut pcao. Vic chn mu 3 hay 4 cn ty thuc vo

th nghim xc nh hm lng ng kh.

Kt qu xc nh hiu sut thu dch

- i vi mu khng c enzyme

Ti tin hnh lm vi khi lng qu ban u l 1kg, tin hnh lm 3 ln v kt

qu trung bnh thu c: 183(g) dch, vy hiu sut trung bnh thu dch l :

183*100%1000

- i vi mu c b sung 0.3ml enzyme pectinaza

Ti tin hnh lm vi khi lng qu ban u l 1kg, tin hnh lm 3 ln v kt

qu trung bnh thu c: 278g dch, vy hiu sut thu dch l

Hiu sut qu trnh = = 18.3%


44/73


278*100%

1000

3.1.2. Kt qu xc nh hm lng ng

Lng ng c s thay i r rt khi b sung lng enzyme pectinaza cc t

l khc nhau. Kt quc th hin bng 3.3 v hnh 2.2.

Bng 3.3: Hm lng ng tng cc mu

Lng enzym pectinaza b

sung (ml)

Mu 1

0

Mu 2

0.1

Mu 3

0.2

Mu 4

0.3

Mu 5

0.4

Lng ng (g/l) 93.47 97.5 99.2 101.5 102.2

T (bng 3.3) ta c biu th hin snh hng ca enzyme pectinaza n

lng dch p (hnh 3.2).

93.4797.5

99.2 101.5 102.2

70

80

90

100

110

Hmlngn

tng(g/l)

0 0.1 0.2 0.3 0.4

Lng enzym pectinaza b sung (ml)

Hnh 3.2: Biu thhin snh hng ca enzyme pectinz n hm lng

ng

Nhn xt v tho lun:T bng 3.3 v hnh 3.2 ta thy: Hm lng ng kh xc nh c ln lt

cc mu tng theo chiu tng ca lng enzyme b sung vo p dch.

Sdc kt qu nh trn l do phn ng thy phn pectin v acid pectinic thnh

mt thnh phn ng n nn sau khi b sung enzyme hm lng ng tng dn

Hiu sut qu trnh = = 27.8%


45/73


ln theo tng ca nng enzyme pectinaza b sung vo. ng thi cc phn t

c mch di cng b thy phn to ra cc ng n. Tuy vy mu 4, 5 hm

lng ng c s chnh lch khng ng k.

Da trn kt qu lng dch thu c, cm quan, hm lng ng th ta thy

mu 4 ( lng enzyme b sung vo 0.3ml/200ml dch qu hay 0.15ml/100ml dch)

cho hiu sut p dch (69.5%) v hm lng ng kh tng i cao (101.5g/l),

ng thi kt qu cm quan dch p c mu p, trong, t vy c.

Theo phn tch nh trn th chcn bsung 0.15ml (0.15%) enzyme pectinaza

vo 100ml tht qu chanh dy th nng cao ng k th tch dch p

(139ml/200ml), hm lng ng (101.5g/l), cht lng dch p (mu p, t vy

c), ng thi cng c li vmt kinh t.

3.2. Kt qu xc nh lng nc b sung vo dch qu

a. Kt quo nng cht kh ban u

Nng cht kh ban u ca nguyn liu c o bng khc x k (Hiu

ATAGO, 0 32%), tin hnh o 3 ln, kt quo c nh sau:

Ln 1: 120g/l; Ln 2: 123g/l; Ln 3: 117g/l.

Vy gi tr trung bnh ca 3 ln o l: 120g/l

Kt quo nng cht kh sau khi pha long cc t l 30, 40, 50% c thhin bng 3.4.

Bng 3.4: Kt qu xc nh nng cht kh sau khi pha long

Kt quo nng cht kh (g/l)

T l H2O

(%) Ln 1 Ln 2 Ln 3

Nng

cht kh

trung bnh

(g/l)

30 92 95 90 92

40 86 88 84 86

50 80 82 78 82


46/73


b. Kt quo pH

pH c o bng my o pH meter (c chnh xc 0.01).Tin hnh o 3 ln.

Kt quo pH trc khi pha long nh sau:

Ln 1: pH = 2.7; Ln 2: pH = 2.7; Ln 3: pH = 2.75

Trung bnh ca 3 ln o l: pH = 2.71

Kt quo pH c c sau khi pha long cc t l H2O 30, 40, 50%c th

hin bng 3.5.

Bng 3.5: Kt quo pH sau khi pha long

Kt quo pHT l H2O

(%) Ln 1 Ln 2 Ln 3

pH trung

bnh

30 3.10 3.15 3.20 3.1540 3.40 3.50 3.40 3.41

50 3.80 3.70 3.90 3.80

c. Kt qu kim nghim cm quan

Sau khi pha long dch chanh dy xong th tin hnh nh gi cm quan dch sau

pha long xc nh b sung nc t l thch hp.

Bng 3.6: Bng im c trng lng sau khi pha long

T l H2O (%)

Ch tiu30 40 50

V 8.6 8.4 8.2

Mi 5.2 5.0 4.8

Mu sc v trong 3.6 3.4 3.4

TBCTL 17.4 16.8 16.4

Da vo bng trn ta thy khi bsung nc vi t l 30, 40, 50% th cht lng

cm quan ca cc mu sau khi pha long khng c sthay i r rt, lng ng

trong dch cng tng i cao, ngha l dch qu vn tc cht lng gn nh

dch ban u.V th, Bsung thm 50% nc so vi lng dch qu chanh dy sau

khi p l thch hp.


47/73


3.3. Kt qu xc nh hm lng ng ln men thch hp

Sau khi b sung ng iu chnh thnh phn dch ln men v tin hnh ln

men n thi gian yu cu ta tin hnh xc nh cc ch tiu sau ln men, bao gm:

- Xc nh cn

- Xc nh hm lng ng cn li

- nh gi cht lng cm quan sn phm

Bng 3.7: Bng im c trng lng khi xc nh hm lng ng thch hp

Nng ng ban u (g/l)

Ch tiu

Mu 1

160

Mu 2

180

Mu 3

200

Mu 4

220

V 5.8 6.6 7.4 7.0

Mi 3.8 4.2 4.8 5.0

Mu sc v trong 3.0 3.2 3.6 3.6

TBCTL 12.6 14 15.8 15.6

Hm lng ng ca dch ln men c nh hng nht nh n qu trnh to

ru. Hm lng ng cao ru hnh thnh s cao. Nhng nu hm lng ng

cao qu th s to p sut thm thu ln lm km hm hot ng ca nm men nn

ru hnh thnh t. Nu hm lng ng t th ccht cho qu trnh ln men t vth ru c hnh thnh khng nhiu. Qu trnh ny c th hin hnh 3.3.

4.7

5.3

5.86.1

3

3.5

4

4.5

5

5.5

6

6.5

ru(%V)

160 180 200 220

Hm lng ng (g/l)

Hnh 3.3:nh hng ca hm lng ng n ru trong qu trnh ln men


48/73


Hm lng ng ca dch ln men ban u cng cao th hm lng ng cn

li sau ln men cao tng ng v c th hin hnh 3.4.

53

61

8293

0

20

40

60

80

100

Hm

lngng

cnli(g/l)

160 180 200 220

Hm lng ng (g/l)

Hnh 3.4 : Sbin i ca hm lng ng trong qu trnh ln men

Nhn xt v tho lun

Lng ng trong dch ban u l 82g/l, nh hn so vi yu cu ca dch ln

men v th cn b sung ng t nng yu cu ca th nghim vi lng l:

Mu 1: 78g/l; Mu 2: 98g/l; Mu 3: 11.8g/l; Mu 4: 13.8g/l. Nh vy hm lng

ng c trong cc mu tng ng l Mu 1: 160g/l; Mu 2: 180g/l; Mu 3: 200g/l;Mu 4: 220g/l

Cc cht ha tan v ng trong dch ln men s to ra nn p sut thm thu

gia mi trng v t bo nm men. S chnh lch ny lm cho nm men d dng

hp th cc cht dinh dng t mi trng v thi ra cc cht khc. S chnh lch

p sut thm thu ny phi nm trong trng thi cn bng th mi duy tr qu trnh

ln men mt cch thun li. Nu nng ng cao tc p sut thm thu ln s

gy c ch qu trnh ln men v nh vy s lm chm qu trnh ln men. Nu nng

ng thp th s thiu cht dinh dng cho nm men sinh trng v ln men v

th qu trnh ln men s yu v s khng tt cho sn phm sau ny.

T bng 3.7, hnh 3.3 v 3.4 cho ta bit:

Ru to ra tng dn theo chiu tng ca nng ng ban u v lng

ng cn li sau ln men gim dn tng ng vi nng ng ban u.


49/73


C th, vi mu ln men nng ng ban u l 160g/l v 180 g/l u cho

CLCQ mc trung bnh (TBCTL ln lt l 12.6, 14.0); ru to ra thp

4.7%V v 5.3%V. Lng ng cn li cng thp (Lng ng cn li ln lt l

53g/l v 61g/l). Do , khng chn 2 mu ny.

mu ln men vi hm lng ng ban u 200g/l cho CLCQ mc kh

(TBCTL l 15.8). ru t c tng i cao (5.8%V), lng ng cn li

khng cao (82g/l) nhng sn phm vn c v ngt kh hi ha.

mu ln men vi nng ng ban u 220g/l ru to ra l 6.1%V, cao

hn cc mu cn li; Lng ng cn li cng tng i cao (93g/l); CLCQ cng

nm mc kh (TBCTL l 15.6).

Nh vy, tng h p cc ch tiu v so snh gia cc mu th mu ln men vihm lng ng ban u 200g/l v 220g/l u thch hp sn xut thnghim

NGK chanh dy ln men tnhin do to ra ru nm trong khong yu cu (5-7%)

v c im cm quan t loi kh, lng ng cn li kh cao. Tuy nhin, trong

sn xut ngi ta khng nhng ch trng cht lng sn phm m cn hng n

tnh knh t v kh nng tiu th sn phm. Nh vy, khi ln men vi hm lng

ng 200g/l s tiu tn lng ng t hn so vi mu ln men hm lng

ng ban u 220g/l. Do , mu ln men vi hm lng ng ban u 200g/l l

thch hp hn cho vic sn xut NGK ln men tdch tri chanh dy.

3.4. Kt qu xc nh pH thch hp cho qu trnh ln men

Khi ln men cc pH khc nhau th c s chnh lch ng k v cht lng cm

quan. C thc th hin bng 3.8.

Bng 3.8: Bng im c trng lng khi xc nh pH ln men thch hp

pH

Ch tiu

Mu 1

3.5

Mu 2

4.0

Mu 3

4.5

Mu 4

5.0

V 5.4 8.6 6.8 5.0Mi 4.4 5.2 4.6 4.0

Mu sc v trong 2.8 3.4 3.0 2.4

TBCTL 13.6 17.2 13.4 11.4


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Nm men hot ng thch hp khong pH nht nh. khong pH thch hp

th qu trnh to ru din ra mnh. Kt qunh hng ca pH n qu trnh hnh

thnh ru c th hin hnh 3.5.

4.7

5.75.3 5.1

3

3.5

4

4.5

5

5.5

6

ru(%V)

3.5 4 4.5 5

pH

Hnh 3.5:nh hng pHn ru trong qu trnh ln men

Kt qu xc nh hm lng ng cn li c th hin hnh 3.6.

96

64

7887

30

40

50

60

70

80

90

100

Hm

lngng

c

li(g/l)

3.5 4 4.5 5

pH

Hnh 3.6:nh hng pHn sbin i hm lng ng trong qu trnh ln men

Lng acid trong dch ln men t nhiu c s ph thuc vo pH ln men, kt qu

nh hng ny c th hin hnh 3.7


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5

4.14.5

5.3

0

1

2

3

4

5

6

axittngsa

ul

men(g/l)

3.5 4 4.5 5

pH

Hnh 3.7:nh hng ca pHn sbin axit tng trong qu trnh ln men

Nhn xt v tho lun

Qua hnh 3.5, 3.6 v bng 3.8 cho thy:

mu 1 th ru tao ra thp 4.5 do nm men hot ng yu v lng ng

cn li nhiu. Tt c cc ch tiu v cm quan u thp, im chung cht 13.6.

sau khi ln men axit cn li tng i t do qu trnh ln men yu lm cho acid

chuyn ha t. Ru c v chua kh chu. T nhng yu t trn m pH = 3.5

khng ph hp cho ln men. mu 2 th ru to ra nhiu, lng ng cn li t. V cm quan cho kt qu

kh cc ch tiu v im chung t loi kh 17.2. Sdnh vy l do pH = 4.0

th nm men hot ng mnh. Lng acid tng sau ln men thp iu ny chng t

pH = 4.0 l thch hp cho qu trnh ln men.

mu 3 mc d cho ru tng i 5.3 v lng axit sau ln men thp

nhng c im cm quan cc ch tiu v im cm quan chung thp 13.4.V do

pH = 4.5 c s hot ng cnh tranh ca cc loi vi sinh vt khc trong c vi

khun lactic to nn cc mi v l cho sn phm v va sn phm khng hi ha. V

th ta khng chon ln men pH = 4.5.

mu 4 th ru to ra khng cao (5.1), lng ng cn li tng i (8.7)

nhng lng axit to ra li cao (5.3), lm cho cht lng cm quan ca sn phm


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khng c tt, im chung v cm quan cht 11.4 v th mu ny cng khng

c chn.

Tnhng bin lun trn ta thy pH = 4 l thch hp cho qu trnh ln men NGK

tdch chanh dy.

3.5. Kt qu xc nh t l nm men b sung thch hp cho qu trnh ln men

Qu trnh nghin cu xc nh t l nm men b sungcho qu trnh ln men sn

xutNGK ln men t dch tri chanh dy thu c nhng kt qu trnh by bng

3.9, hnh 3.7 v hnh 3.8.

Bng 3.9: Bng im c trng lng khi xc nh t l nm men b sung

T l men (%)

Ch tiu

Mu 1

1

Mu 2

1.5

Mu 3

2

Mu 4

2.5

V 7.2 8.4 7.6 6.8

Mi 3.8 4.8 4.2 3.8

Mu sc v trong 3.0 3.2 2.8 2.8

TBCTL 14 16.4 14.6 13.4

T l nm men b sung nh hng n s tao ru c biu hin hnh 3.8.

5.4

5.9 6.36.8

3

4

5

6

7

8

ru(%V)

1 1.5 2 2.5

T l men (%)

Hnh 3.8:nh hng ca lng nm men bsung n qu trnh to ru


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T l nm men b sung nh hng n hm lng ng cn li c biu hin

hnh 3.9.

8981

76

63

30

40

50

60

70

80

90

100

Hmlngn

cnli(g/l)

1 1.5 2 2.5

T l men (%)

Hnh 3.9:nh hng ca lng nm men bsung n hm lng ng cn li

Nhn xt v tho lun

Da vo hnh 3.7, 3.8, bng 3.9 cho ta thy:

mu 1 ru to ra khng cao 5.3, lng ng cn li cao 8.9, im cm quan

chung thp 14. l do lng nm men b sung vo cha ln men, cc ch

tiu cm quan cha c cao. Nn t l men b sung 1% l khng thch hp cho

qu trnh ln men.

mu 2 ru to ra tng i cao 5.9, ng cn li ch 8.1 va im cm

quan tng i cao 16.4 l do lng nm men b sung vo thch hp. To iu kin

thun li cho qu trnh ln men. Sn phm c v hi ha, mi thm d chu. Nn vi

t l men 1.5% l thch hp cho qu trnh ln men.

mu 3 cn to ra cao 6.3 lng ng cn li t 7.6 nhng c im cm

quan chung mc trung bnh 14.6, sn phm c v khng hi ha, khng trong v

mu khng p.

mu 4 ru to ra cao (6.8) do lng nm men b sung nhiu nn lng ccht c phn gii to ra ru nhiu v th ru tao ra ln.. im cm quan

chung ca mu 4 khng cao (13.4).

Vy ta thy mu 2 vi t l men bsung 1.5% l thch hp cho ln men NGK t

dch chanh dy.


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3.6. Kt qu xc nh thi gian ln men thch hp

Thi gian ln men c tnh quyt nh n cht lng ca sn phm NGK ln

men c cn thp. Nu thi gian ln men ngn th sn phm cha t c tnh

cht c trng ( ru, mu, mi, v). Nu thi gian ln men di th lm cho

ru cao, c mi v khng tt. V th ti tin hnh xc nh thi gian ln men thch

hp cho sn phm chanh dy ln men. Kt qu cm quan c th hin bng 3.10.

Bng 3.10: Bng im c trng lng khi xc nh thi gian ln men

Thi gian ln men

(h)

Ch tiu

Mu 1

48

Mu 2

60

Mu 3

72

Mu 4

84

V 6.2 7.0 8.0 6.8Mi 2.8 3.2 3.8 3.2

Mu sc v trong 2.2 2.6 3.4 3.6

TBCTL 11.2 12.8 15.2 13.6

Thi gian ln men c nh hng trc tip n qu trnh hnh thnh ru. Lng

ccht trong dch ln men cn th thi gian ln men cng di th ru to ra

cng ln v ngc li nu thi gian ln men ngn th d ru to ra thp. Snhhng ca thi gian ln men n qu trnh to ru c th hin hnh 3.10.

4.7

5.2

5.8

6.5

33.5

4

4.5

5

5.5

6

6.5

ru(%V)

48 60 72 84

Thi gian ln men (h)

Hnh 3.10:nh hng ca thi gian ln men n qu trnh hnh thnh ru


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Thi gian ln men cng di th ru to ra cng cao v hm lng ng cn li

cng thp. Kt quc th hin hnh 3.11.

96 9182

75

30405060708090

100

Hm

lngn

cnli(g/l)

48 60 72 84

Thi gian ln men (h)

Hnh 3.11:nh hng ca thi gian ln men n lng ng cn li

Nhn xt v tho lun

Qua hnh 3.9, 3.10 cho thy: ru tng dn theo thi gian ln men v hm

lng ng cn li gim theo thi gian ln men.

mu 1 ru to ra thp (4.7), hm lng dng cn li cao (9.6). im

cm quan chung thp (11.2). Sn phm c cc ch tiu v mt cm quan u thp:

V (6.2), Mi (2.8), Mu sc v trong (2.2). mu 1 c thi gian ln men ngn48 h cha to ra cc tinh cht c trng ca sn phm.

mu 2 ru tao ra cn thp (5.2), im cm quan chung khng cao hn so

vi mu 1 nhiu (12.8).

mu 3 ln men 72h th c s khc bit so vi mu 1 v mu 2. ru to

ra tng i cao (5.8), lng ng cn li thp (8.2), im cm quan chung mc

kh (15.2). iu ny chng t sau 72h ln men th gn nh to ra c cc tnh cht

ca sn phm yu cu: V ru, lng ng cn li, v, mi, mu sc, trong.

mu 4 c thi gian ln men 84 h, lng ng c chuyn ha nhiu v th

ru to ra (6.5) cao hn cc mu 1, 2, 3. Lng ng cn li thp. im cm

quan chung khng cao 13.6.

Vy mu 3 ln men 72h l ph hp nht cho ln men nc gii kht tdch

chanh dy.


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3.7. Kt qu th nghim iu v

iu v nhm to ra v hi ha cho sn phm, v mt cm quan cho gi tr cao.

ng thi cng lm tng gi tr dinh dng cho sn phm sau ln men. V vy sau

qu trnh ln men th sn phm cn c iu v bng syrup 65%.

im cm quan ca cc mu th nghim iu vc th hin bng 3.11.

Bng 3.11: Bng im cm quan iu v sn phm

T l syrup b sung (%) TBCCTL HSQT TBCTL

5 3.6 7.2

6 4.2 8.4

7 3.4 6.88 3.2

2.0

6.4

7.2

8.4

6.8 6.4

0

2

4

6

8

10

im

trungbn

ctrnglng

5 6 7 8

T l syrup b sung (%)

Hnh 3.12: Biu thhin im cm quan c trng lng ca th nghim iu v

Nhn xt:

T hnh 3.11 cho thy khi iu v6% cho im cm quan cao nht (8.6). V

ngt hi ha vi cc v khc ca sn phm. iu v5% v sn phm cn nht, cht

lng cm quan ca sn phm thp (7). Khi iu v7%, 8% th sn phm c vngt cao nn cht lng cm quan ca sn phm gim, v lng ph mt lng

ng. Vy tin hnh iu v vi syrup ng t l 6% l thch hp cho sn phm

NGK ln men tdch chanh dy.


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3.8. S hon thin quy trnh sn xut thnghim sn phm nc gii kht

ln men tdch qu chanh dy

Nc 50%

Hnh 3.13. S quy trnh hon thin sn xut thnghim nc gii kht ln men

tdch chanh dy

Thanh trng

Chit chai(thy tinh 240ml)

Sn phm

ng,Na2CO3

Ln men

Thanh trng

Tng sinh

X l sau ln men( iu v6% syrup)

t0 = 600C

T= 15 pht

t0 = 25-270C,TH = 200Brix,TLMTH = 1.5%,

tTH = 72giPh TH = 4.0

t0=60 - 620CT= 30pht

X l

Enzymepectinaza

p ly dch

Chanh dy

t0 = 400C

T= 60 pht

Phi ch

Pha long

Nm menchm


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Thuyt minh quy trnh

Nguyn liu: Nguyn liu c vai tr quyt nh cht lng ca sn phm.

Nguyn liu chanh dy dng ch bin nc gii kht ln men phi l chanh dy c

chn k thut (mu tm, b mt hi nhn, b ra c dch mu vng ti, mi thm

c trng), khng b su bnh, ng thi, khng bm dp.

X l: Tri chanh dy khi mi mua vc em i ra sch loi b nhng

tp cht ln vo. Sau bi qu tch b v ch ly phn cm v dch. Khng nn

dng dng c kim loa cha dch. V chuyn sang cng on tip theo.

v b sung enzym Pectinaza: Dng pipet 1ml ht enzyme cho vo dch vi

t l 0.15%. sau trn u cho enzyme phn tn u trong dch qu. Sau tin

hnh em i trong bn nhit vi nhit 40oC, trong 1 h,nhm mc ch thu

c nhiu dch v nng cao cht lng dch p.

p dch: Sau khi cn tin hnh p dch ngay (y ti dng vi mng lc),

lc ri iu chnh thnh phn ca dch tin hnh ln men ngay, trnh hin tng

oxy ha.

Phi ch: Dch p c pha thm 50% nc l gim gi thnh sn phm, s

c nng cht kh khong 88.5oBx, ngha l dch ln men cn thiu khong

1213oBx na. Do , tin hnh b sung ng dch ln men t 20oBx. ngthi, dch p c pH thp (khong 2.5 3.0). Do vy, cn b sung thm Na2CO3

iu chnh pH dch v 4.0. Na2CO3 c ha tan trong nc ri nh t t vo dch

p cho n khi t gi tr pH yu cu.

ng c o bng khc x k (Hiu ATAGO, 0 32%), pH c o bng

my o pH meter (C chnh xc 0.01).

Thanh trng: Dch p c thanh trng 60oC trong 15 pht dit khun,

enzym v to iu kin cho qu trnh ha tan cc cht dng iu chnh thnh phnvo dch ln men.

Ln men: Sau khi thanh trng dch p c lm ngui v cho ln men ngay.

Dch p c ln men trong bnh tam gic 500ml, dch ln men chim khong

43 th tch bnh. Thc hin ln men ym kh26 1oC, trong thi gian 72h.


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Xl sau ln men: Sau khi kt thc ln men, nc gii kht c lng gn sau

lc bng vi lc, ri tin hnh iu v sn phm vi t l syrup b sung l 6%.

Sau em i thanh trng 60 620C nh ch qu trnh ln men v tiu dit vi

sinh vt dc bit l vi khun lactic. Tip n em sn phm i chit chai thy tinh

240ml, ng np, bo qun v s dng.

3.9. Sb tnh ton gi thnh sn phm trong phng th nghim

Sb tnh ton gi thnh cho 1 lt sn phm nc gii kht t chanh dy nh sau:

Bng 3.12: Hoch ton chi ph thnh phm

Chi phS

lngn gi

Thnh tin

ng ()

Mt 1.kg 8.000 ng/kg 8.000

Enzym Pectinaza 7,5 ml 880.000 ng/l 6.600

ng 150g 12.000ng/kg 1.800

Na2CO3 1.5g 90.000ng/kg 135

Nm men 20ml 20ng/1ml 400

Chai thy tinh 240ml 1 chai 1.000 ng/chai 1.000

Chi ph khc (in, nc, nhn

cng, khu khao ti sn) - - 3.000

Tng cng - - 20.935

T bng 3.11 cho thy, ch bin 1 lt thnh phm phng th nghim chi ph

sb l 20.935ng. ng chai c dung tch 240ml. Do , gi thnh ca 1 chai

240ml sn phm NGK ln men t nguyn liu chanh dy l 5.030ng.

Tuy nhin, nu a vo sn xut ln gi thnh mua nguyn vt liu (mua s, mua

vo chnh v) th gi thnh cho 1 chai sn phm s nh hn 5.030

ng.T nhng kt qu nghin cu c cho thy NGK ln men t ngun liu chanh

dy c tha vo sn xut c. Vi sn phm c v chua ngt hi ha, mu nu

vng rt bt mt, c trong kh cao v cc ch tiu vi sinh vt t tiu chun ca

b y t. Sn phm nc gii kht ln men t dch chanh dy sp ng c nhu


60/73


cu ca ngi tiu dng. Ph hp vi c ph n v ngi gi. Sau y l mt vi

hnh nh v sn phm nc gii kht ln men t dch chanh dy t nhin.

Cht lng cm quan ca sn phm sn xut theo quy trnh hnh 3.13 c nh

gi v th hin qua bng 3.13

Bng 3.13: Bng im c trng lng ca sn phm NGK ln men t dch qu

chanh dy

Ch tiu TBCTL

V 8.4

Mi 5

Mu sc v trong 3.2

im chung 16.6

Hnh 3.14: Dch chanh dy ang ln men

Hnh 3.15: Sn phm nc gii kht ln men t dch chanh dy


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KT LUN V XUT KIN

Kt Lun

T nhng kt qu thu c cho thy, hon ton c th ch bin nc gii kht t

dch qu chanh dy theo cc s liu nh sau:

- Lng enzym Pectinaza b sung thch hp: 0,15ml/100g(0.15%) nguyn liu.

- Lng nc b sung 50% so vi dch qu

- 40oC trong 1h.

- Lng nm men b sung thch hp: 1.5% so vi th tch dch ln men.

- pH ln men: 4,0

- Nhit qu trnh ln men: 26 1oC.

- Thi gian ln men thch hp: 72h.

- iu v vi syrup 65oBx vi t l 6% so vi dch ln men

Theo cc thng s chn nh trn th sn phm to thnh c im cm quan

chung ca sn phm l 16.6 (bng 3.13), nm trong khong 15.2 18.5 v theo

TCVN 3215 79 quy nh phn cp sn phm (ph lc 3, t 15.2 18.5 im th

sn phm t loi kh) nn sn phm t loi kh.

Kin ngh

Sau 3 thng thc tp v hon thnh ti ti phng th nghim trng i HcNha Trang, ti c mt s xut nh sau:

- Trong qu trnh nguyn liu vi enzym pectinaza 40oC, y l nhit

thch hp cho enzym hot ng, ng thi y cng l nhit thch hp cho cc

enzym oxy ha kh hot ng mnh gy ra hin tng oxy ha nc qu v sau,

lm nh hng n cht lng thnh phm. Do , ti xin ngh cn c nhng

nghin cu su hn v snh hng ca nhit n qu trnh oxy ha nc qu

v cht lng ca sn phm.- Khi nghin cu, ti tin hnh ln men trong iu kin nhit ca mi trng

nn ti khng kim sot c snh hng ca nhit n tin trnh ln men. Kt

qu ti thu c cn hn ch. V vy, ti xin ngh cc tc gi sau nn nghin cu


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su hn v snh hng ca nhit n tin trnh ln men, a ra kt qu chnh

xc hn ch bin thnh sn phm c cht lng tt hn.

- Vi nhng kt qu thu c t qu trnh nghin cu ch bin sn phm nc

gii kht ln men t dch chanh dy, y l mt sn phm mang tnh t nhin cao,

thch hp cho nhiu i tng tiu dng, ph hp vi th hiu ngi tiu dng hin

i. Do vy, ti xin ngh nn nghin cu trn cc i tng khc lm phong

ph thm ngun sn phm trn th trng trong v ngoi nc, thm nhiu s la

chn cho khch hng, ng thi to ra nhng hng i mi cho cc ngun nguyn

liu khc nhau.

- Dch chanh dy c chua cao nn khi ln men v thanh trng s xut hin cc

mi v l. V th ti xin kin ngh nghin cu k hn v vn ny.

- V chanh dy Vit Nam c trng c tnh ma v, bo qun khng c lu

di nn khng chng c nguyn liu. V th ti xin kin ngh nghin cu ch

bo qun chanh dy.


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TI LIU THAM KHO

1. ng Vn Hp (2005) - Phn tch kim nghim thc phm thy sn, NXB nng

nghip.

2. H Duyn T (2000), Kim nghim thc phm bng phng php cm quan-

NXB Khoa hc v k thut.

3. L Ngc T (2002),Ha sinh cng nghip- NXB Khoa hc v k thut.

4. Lng c Phm (1998), Cng ngh vi sinh vt- NXB Khoa hc v k thut H

Ni.

5. Nguyn nh Thng (2000), Cng ngh sn xut v kim tra cn etylic-NXB

Khoa hc v k thut H Ni.

6. Trn Minh Tm (2000), Cng ngh vi sinh ng dng-NXB Nng Nghip TP H

Ch Minh.

7. Trn Th Luyn (1998), Cng ngh chbin cc sn phm ln men- NXB Nng

nghip TP H Ch Minh.

8. Trn Th Thanh (2001), Cng ngh vi sinh- NXB Gio dc.

9. V Cng Hu (2004), Cy tri min nam- NXB TP H Ch Minh

10. V Cng Hu (1983), Chbin ru vang tri cy gia nh - NXB Nng Nghip TP

H Ch Minh

11. Nc gii kht ln men hng v chanh dy tnhin, Trn Minh

Tm, cp nht lc 11h ngy 3 thng 7 nm 2009.

http://thucphamvadoisong.vn/.


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PH LC

I. PH LC 1: CC PHNG PHP PHN TCH KIM NGHIM

1. Xc nh cn ca dch ln men

ru l mt trong nhng ch tiu quan trng nh gi mc ln men ca

dch ln men v cht lng sn phm.

ru c th bng cn k, t trng k hoc bng phng php ha hc.

Tuy nhin vi sn phm nc gii kht ln men c cn thp, nu o bng cn k

hoc t trng k s khng chnh xc. Do nn s dng phng php ha hc

xc nh ru. Cch tin hnh nh sau:

Nguyn l:

Nhm chc ru b oxy ha thnh axit bi hn hp nitrocromic d. Phnnitrocromic dc nh lng bng iot.

Phn ng:

( ) OHCOOHCHKNONOCrHNOOHHCOCrK 23333352722 3441632 +++=++

( ) OHIKNONOCrHNOKIOCrK 223333722 6821462 +++=++

NaIOSNaOSNaI 22 6423222 +=+

Ha cht:

Hn hp nitrocromic:

- Kali bicromat: 4,9g

- Axit nitric m c: 1000ml

Dung dch KI 10%:

- Kali iotua: 100g

- Nc ct va : 1000ml

Tin hnh:

Ly 200ml dch ln men cn xc nh ru vo bnh cu 250ml ca dng c

v ct cho n gn cn. Khi ct ch khng cn b bay hi bng cch cho ung sinh hn ca thit b chng ct ngp trong 10ml nc ct v ng sinh hn c

lm lnh bi nc lnh khng qu 20oC. Nu dch ct khng 200ml th cho thm

nc ct va 200ml.

Sau , cho vo bnh nn 250ml c nt kn:

- Dch ct: 5ml


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http://www.ebook.edu.vnii

- Nc ct: 5ml

- Dung dch nitrocromic: 10ml

- y nt kn bnh, trong 30 pht, sau cho thm:

- Dung dch Kali iotua: 10ml

- Nc ct: 100ml

Lc u sau 2 pht ri chun lng iot t do gii phng ra bng dung dch

Natri hyposunfit 0,1N cho n khi dung dch trong bnh chuyn sang mu xanh lc

ca mui crom (III) th dng. Trong trng hp, nu cho dung dch nitrocromic vo

c mu xanh lc ngay l dung dch nitrocromic cha d, cn phi cho thm dung

dch nitrocromic hay dng lng dch th t hn na.

Lm song song cng mu trng bng cch thay dch th bng nc ct. Thc

hin thao tc ging nh khi xc nh mu th.

Tnh kt qu:

( )

10007933,05

10015,10

=

FVVR

Trong :

- V: S ml NOSNa 1,0322 dng chun mu th

- V0: S ml NOSNa 1,0322 dng chun mu trng

- F: H s pha long- 1,15: C 1ml NOSNa 1,0322 th tng ng vi 1,15mg ru etylic

- 0,7933: T trng ca ru etylic

2. Xc nh hm lng ng tng s bng phng php Bertrand

Nguyn l

Gluxit kh trc tip oxy c tnh kh ca ( )2OHCu mi trng kim mnh, lm

cho n kt ta di th OCu2 mu gch. S ml OCu2 tng ng vi s lng

gluxit kh oxy.

Phn ng

( ) OHOCuRCOOHOHCuRCHO 222 22 =+=+

OCu2 c tnh kh oxy tc dng vi mui st (III) (Fe+++) lm cho mui ny

chuyn thnh mui st (II) (Fe++) trong mi trng axit.


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http://www.ebook.edu.vniii

( ) OHFeSOCuSOSOHSOFeOCu 244423422 22 ++=++

4FeSO c tnh kh, do dng 4KMnO l cht oxy ha chun mi

trng axit.

( ) OHSOFeMnSOSOKKMnOSOHFeSO 23424424424 822810 +++=++

T s ml 4KMnO tiu tn chun 4FeSO hnh thnh, tra bng tm s mg

ng glucoza, maltoza, lactoza hoc saccaroza trong mu (mg) nhn vi h s pha

long ta c hm lng ng trong 100g thc phm.

Tin hnh

Chun b mu th:

ong 10ml dch cn xc nh. Lng cht th ly phi thch hp sao cho phn

dch lc em i chun c nng ng l 4 10 %.Cho mu vo bnh nh mc 100ml, trng ra dng cng mu vi ln bng

nc ct (Lng nc ra khng c qu th tch bnh nh mc).

Trung ha axit hu cc trong mu th bng dung dch %10NaOH n pH = 7

(Kim tra bng giy o pH).

un cch thy bnh nh mc 80oC trong 15 pht, thnh thong lc u trong

khi un. Sau , mu th ngui n nhit phng, kh tp cht bng

( ) %1023COOCHPb . Cui cng, b sung nc ct va n vch nh mc.

lng lc b kt ta.

Trong mu c ng Saccaroza nn ta thy phn bng cch ly 20ml dch lc

trn cho vo bnh nh mc 100ml. Cho 5ml HCl c, un cch thy 70oC trong 5

pht. Sau , lm ngui nhanh ri trung ha bng %10NaOH n pH

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