qui-trinh-san-xuat-nuoc-mam

8/6/2019 Qui-trinh-san-xuat-nuoc-mam

1/32

http://www.ebook.edu.vn 0

Trng i Hc Cn ThKhoa Nng Nghip & SHD

B mn Cng Ngh Thc Phm

Semina chbin thy v hi sn

Qui trnh sn xut

nc mmNhm sinh vin thc hin:

Nguyn Th Ngc GiangNguyn Th Bch ThuTrn Kim ChiNguyn Th Tuyt VnTrng Mai Tuyt Dimng Minh Ngc DimNguyn Th Hunh NhL Quan NghLp: CNTP LT K33

Cn Th, 11/2008


2/32


I. Gii thiu ............................................................................................................................... 3

II. Nguyn liu sn xut ............................................................................................................ 3

II.1 C ................................................................................................................................... 3

II.1.1 Protein ..................................................................................................................... 5

II.1.2 Thnh phn trch ly cha nitphi protein ............................................................... 6

II.1.3 Lipid ........................................................................................................................ 8

II.1.4 Glucid .................................................................................................................... 10

II.1.5 Cc loi vitamine v khong cht ......................................................................... 10

II.1.6 Tnh cht vt l ca ng vt thy sn .................................................................. 10

II.1.7 Tnh cht ha hc th keo ca ng vt thy sn ................................................. 12II.2 Mui n ........................................................................................................................ 13

II.2.1 Thnh phn mui n .............................................................................................. 13

II.2.2 Cc tnh cht ca mui n ..................................................................................... 13

II.2.3 Cc phng php p mui .................................................................................. 14

III. Quy trnh sn xut ............................................................................................................. 15

IV. Csl thuyt .................................................................................................................. 16

IV.1 Bn cht ca cc qu trnh sn xut nc mm .......................................................... 16IV.2 Cc h enzyme trong sn xut nc mm .................................................................. 17

IV.2.1 H enzyme Metalo protease (aminodipeptidase) ............................................. 17

IV.2.2 H enzyme serin protease ................................................................................. 17

IV.2.3 H enzyme acide protease ................................................................................ 17

IV.3 Vi sinh vt trong sn xut nc mm ......................................................................... 18

IV.4 Nhn tnh hng n qu trnh ch bin nc mm ............................................... 18

IV.4.1 Nhit ............................................................................................................... 18

IV.4.2 pH ........................................................................................................................ 18

IV.4.3 Lng mui ......................................................................................................... 18

IV.4.4 Din tch tip xc ................................................................................................. 19

IV.4.5 Bn thn nguyn liu ........................................................................................... 20

V. Thuyt minh quy trnh ....................................................................................................... 20

V.1 X l nguyn liu ......................................................................................................... 20


3/32


V.1.1 C .......................................................................................................................... 20

V.1.2 p mui .............................................................................................................. 21

V.2

................................................................................................................................... 21

V.3 Giai on ln men - ch bin chp c truyn ............................................................ 21

V.4 Chit rt........................................................................................................................ 23

V.5 Phi trn ....................................................................................................................... 23

VI. Nhng hin tng h hng ca chp ............................................................................. 23

VI.1 Chp chua ................................................................................................................. 23

VI.2 Chp en ................................................................................................................... 24

VI.3 Chp thi .................................................................................................................. 25VI.4 Nc mm thi v cch phng cha .......................................................................... 26

VII. Cc ch tiu phn loi, kim tra chp nc mm .......................................................... 26

VII.1 Phn loi chp ......................................................................................................... 26

Chia lm 3 loi .................................................................................................................... 26

VII.2 Ch tiu nh gi chp chn .................................................................................... 26

VII.2.1 Cm quan ............................................................................................................ 26

VII.3 Tiu chun ca nc mm thnh phm ..................................................................... 27VII.4 Bo qun nc mm .................................................................................................. 27

VIII. Gi tr dinh dng ca nc mm ................................................................................. 28

VIII.1 Cc cht m ............................................................................................................ 28

VIII.2 Cc cht bay hi ....................................................................................................... 28

VIII.3 Cc cht khc ........................................................................................................... 28


4/32


I. Gii thiu

Nc mm l sn phm c ln men t cc loi c, l sn phm truyn thng ca

dn tc Vit Nam. Nc mm gn lin vi i sng hng ngy v l mt bn sc rt ringca dn tc Vit Nam.

Kt qu nghin cu v thnh phn ha hc v cng ngh sn xut nc mm c

cc nh khoa hc a ra cc kt lun sau:

1. Nc mm l hn hp acide amin. Cc acide amin ny c to thnh do s thyphn ca protease. Cc protease ny l do vi sinh vt tng hp nn.

2. Mui c tc dng c ch vi sinh vt gy thi, t l mui thch hp l 20 25%.3. Tc dng lm ngu v to hng ngoi protease ca vi sinh vt cn c cc enzyme

tiu ha ctrong ni tng c.

4. Nhit c tc dng rt ln n hot ng ca cc enzyme trong qu trnh sn xutnc mm. Nhit thch hp l 36 440C.

5. Trong qu trnh thy phn, acide tng. Ban u ca qu trnh lm nc mm, mitrng kim yu c tc dng rt tt.

II. Nguyn liu sn xutII.1 C

Nguyn liu chnh dng sn xut nc mm l cc loi c. Tuy nhin cht lng

nc mm li ph thuc rt nhiu vo tng loi c. Chnh v th, vic chn c sn xut

nc mm l iu m cc nh sn xut quan tm.

Thnh phn ha hc gm: nc, protein, lipid, mui v c, vitamine,... Cc thnh

phn ny khc nhau rt nhiu, thay i ph thuc vo ging, loi, gii tnh, iu kin sinh

sng,... Ngoi ra, cc yu t nh thnh phn thc n, mi trng sng, kch cc v cc ctnh di truyn cng nh hng n thnh phn ha hc, c bit c nui. Thnh phn ha

hc ca c tng cquan, b phn c s khc nhau.


5/32


Bng 1: Thnh phn ha hc ca c

Thnh phn

Ch tiu

Nc Protein Lipid Mui v c

Tht c 48 85,1 10,3 24,4 0,1 5,4 0,5 5,6

Trng c 60 70 20 30 1 11 1 2

Gan c 40 75 8 18 3 5 0,5 1,5

Da c 60 70 7 15 5 10 1 3

S khc nhau v thnh phn ha hc ca c v s bin i ca chng c nh hngn mi v v gi tr dinh dng ca sn phm, vic bo qun ti nguyn liu v qui trnh

ch bin.

Bng 2. Thnh phn ha hc c nc ngt

TTThnh phn ha hc (% khi lng)

Nc Protide LipideTn loi c

1 C dic 85 13,0 1,1

2 C chp 79 18,1 1,5

3 Trm en 77 17,9 3,8

4 M en 82 14,5 0,6

5 M trng 86 10,0 1,0

6 Lng canh 76 15,6 2,3

Bng 3. Thnh phn ha hc c bin

TTThnh phn ha hc (% khi lng)

Nc Protide LipideTn loi c

1 Nc s 76.80 21.75 0.85

2 Mi thng 77.50 19.26 1.80

3 Trch 75.90 21.76 3.15

4 Phn hai sc 76.20 20.35 2.20


6/32


5 Ln ngn 79.30 19.03 1.21

6 Cm 75.14 11.25 2.10

7 Mi 76.60 9.37 14.408 L p 81.84 10.00

9 Chun 76.17 9.75 7.50

Yu tnh hng r nht n thnh phn ha hc ca c l thnh phn thc n.

II.1.1 Protein

c cu to t cc acide amin, cc acide amin khng thay th quyt nh gi tr dinh

dng ca thc phm. Protein ca c l ngun giu cc acide amin c cha lu hunh v

lysine. Protein ca c chia lm 3 phn:

II.1.1.1 Protein cu trc (protein tc)

Gm cc si myosin, actin, actomyosin v tropomyosin chim khong 65 75% tng

hm lng protein trong c. Cc protein cu trc ny c chc nng co rt m nhn cc hot

ng ca c. Myosin v actin l cc protein tham gia trc ti p vo qu trnh co dui c.

Protein cu trc c kh nng ha tan trong dung dch mui trung tnh c nng ion kh cao(> 0,5M).

II.1.1.2 Protein cht c(protein tng c)

Gm myoglobin, myoalbumin, globulin v cc enzyme, chim khong 25 30% hm

lng protein trong c. Cc protein ny ha tan trong nc, trong dung dch mui trung tnh

c nng ion thp (< 0,15%). Hu ht protein cht cbng t khi un nng trong nc

nhit trn 500C.

Trong qu trnh ch bin v bo qun, myoglobin d b oxy ha thnh metmyoglobin,nh hng n mu sc ca sn phm.

II.1.1.3 Protein m lin kt

Bao gm cc si collagen, elastin. Hm lng collagen ctht c thp hn ng

vt c v, thng khong 1 10% tng lng protein v 0,2 2,2% trng lng ca ctht.

Chim khong 3% c xng v khong 10% c sn. C trong mng li ngoi bo,

khng tan trong nc, dung dch kim hoc dung dch mui c nng ion cao.


7/32


im ng in pI ca protein c vo khong pH = 4,5 5,5. Ti gi tr ny protein

c ha tan thp nht.

Cu trc hnh thi c

a protein c d

b

bin

i do mi tr

ng v

t l thay

i. Tnh tan

ca protein trong si cthay i sau khi ng kh.

Vic x l vi nng mui cao hoc x l bng nhit c th dn n s bin tnh

sau cu trc protein b thay i khng hi phc c.

Protein tng cc kh nng ha tan cao trong nc, lm mt gi tr dinh dng do

mt lng protein ng k thot ra khi ra, p mui, tan gi,... V vy cn ch duy tr

gi tr dinh dng v mi v ca sn phm.

Protein m lin kt da c, bong bng c, vch ckhc nhau. Cc si collagen ccm ca c to nn cu trc mng li mng vi mc phc t p khc nhau. Tuy nhin

collagen ca c km bn nhit v t c cc lin kt cho hn nhng nhy cm hn collagen

ng vt mu nng c xng sng.

II.1.2 Thnh phn trch ly cha nitphi protein

Cht phi protein l thnh phn ha tan trong nc, c khi lng phn t th p v

chim khong 9 18% tng hm lng protein c c xng, khong 33 38% cc loi csn. Thnh phn chnh ca h p cht ny bao gm cc cht bay hi (amoniac, amine,

trimethylamin), trimethylamineoxide (TMAO), dimethylamineoxid (DMAO), cc acide

amine t do, ure (c nhiu trong c sn), nucleotide, ...

Thnh phn cht trch ly cha nitphi protein khc nhau ph thuc vo loi, kch c,

ma v, phn cly mu, ...

Cc cht trch ly cha nitphi protein rt quan trng i vi cc nh ch bin thy

sn bi v chng nh hng n mi tnh cht ca thc phm nh: mu sc, mi v, trngthi cu trc, dinh dng, s an ton v s h hng sau thu hoch.

II.1.2.1 Trimethylamineoxid (TMAO)

TMAO l thnh phn c trng v quan trng ca nhm cht cha nitphi protein.

TMAO c ch yu trong cc loi c nc mn v t c tm thy trong cc loi c nc

ngt. Hm lng TMAO trong cc loi c khc nhau ty theo loi, iu kin sinh sng, kch


8/32


c. C hot ng bi li nhiu, kch cln cha nhiu TMAO hn c nh v t bi li trong

nc. Hm lng TMAO cha cao nht trong cc loi c sn (c nhm), mc,........

Theo Tokunaga (1970), hm l

ng TMAO trong c n

i nh

c trch, c thu, c ng

tp trung cao nht trong c tht sm, trong khi cc loi c y tht trng c hm lng

TMAO cao hn nhiu trong ctht mu sng. TMAO c vai tr iu ha p sut thm thu

ca c, v vy gip c chng li p sut thm thu gy ra do s chnh lch nng mui

trong nc bin.

II.1.2.2 Cc acide amine tdo

Cc acide amine t do chim khong 0,5 2% trng lng c tht, chng gp phn

to nn mi vc trng ca nguyn liu. Hm lng acide amine t do cng nhiu th vikhun gy h hng pht trin cng nhanh v sinh ra mi amoniac. Cc loi c c ctht sm

v thng vn ng nh c ng, c thu c hm lng histidine cao. C tht sm cha

histidine cao hn tht trng. Trong thi gian bo qun histidine b vi sinh vt kh nhm

carboxyl hnh thnh c t histamine.

II.1.2.3 Ure

Ure c ph bin trong tt c c tht c, nh ni chung c t hn 0,05% trong c tht

ca c xng, cc loi c sn bin cha mt lng ln ure (1 2,5%). Trong qu trnh boqun ure phn hy thnh NH3 v CO2 di tc dng ca enzyme urease ca vi sinh vt. Do

ure ha tan trong nc v thm qua mng t bo nn n dc tch ra.

II.1.2.4 Amoniac

Amoniac c mi c trng (mi khai). Trong c tht ca c ti c lng nh

amoniac. Trong c xng lng amoniac thp nhng khi b h hng do vi sinh vt th lng

amoniac tng nhanh. Khi s h hng tin trin, pH ca ctht chuyn sang mi trng kim

do lng amoniac tng ln v to nn mi n thi ca c.

II.1.2.5 Creatine

L thnh phn chnh ca hp cht phi protein. C trng thi ngh ngi creatine tn ti di

dng mch vng phospho v cung cp nng lng cho qu trnh co c.


9/32


II.1.2.6 Enzyme

Enzyme l protein, chng hot ng xc tc cho cc phn ng ha hc trong ni

tng v trong c

th

t. Enzyme tham gia vo qu trnh trao

i ch

t

t

bo, qu trnh tiu

ha thc n v tham gia vo qu trnh t cng. Sau khi cht, enzyme vn cn hot ng, v

th gy nn qu trnh t phn gii ca c lm nh hng n mi v, trng thi cu trc v

hnh dng ca chng. Sn phm ca qu trnh phn gii do enzyme l ngun dinh dng cho

vi sinh vt, lm tng tc n hng.

Trong nguyn liu c nhiu enzyme khc nhau. Cc nhm enzyme chnh nh hng

n cht lng nguyn liu l: enzyme thy phn v enzyme oxi ha kh.

Nhiu loi protease c tch chit t c tht c v c tc dng phn gii lm mmm c. S mm ha m c gy kh khn trong ch bin. Cc enzyme thy phn protein

quan trng trong nguyn liu gm: Cathepsin, protease kim tnh, collagenase, pepsin

trypsin, chimotripsin.

Cc enzyme thy phn lipid quan trng gm: lipase, phospholipase. Chng thng c

trong cc cquan ni tng v trong ctht. Enzyme thy phn lipid rt quan trng i vi c

ng lnh, cc loi c ny lipid c th b thy phn khi hot ng ca nc thp. Qu

trnh bo qun lnh ng cc acide bo t do c sinh ra t phospholipid v triglycerit, cnh hng xu n cht lng ca c. Acide bo t do gy ra mi v xu, nh hng n cu

trc v kh nng gi nc ca protein ctht.

Cc enzyme oxy ha bao gm: phenoloxidase, lipoxygenase, peroxidase.

Polyphenoloxidase c bit qua trng trong tm v chng l nguyn nhn gy nn m en

cho nguyn liu sau thu hoch.

II.1.3 Lipid

C s dng cht bo nh ngun nng lng d tr duy tr s sng trong nhng

thng ma ng, khi ngun thc n khan him.

Hm lng lipid dao ng nhiu (0,1 30%). C c phn loi theo hm lng cht

bo nh sau:

+ C gy (


10/32


+ C bo (>10% cht bo) nh c hi, c trch, c thu,...

Loi c Hm lng cht bo

C tuyt 0,1 0,9C bn 0,5 9,6

C sao 1,1 3,6

C herring 0,4 30

C thu 1 - 35

II.1.3.1 Sphn cht bo trong c

Cht bo ca cc loi c bo thng tp trung trong m bng v y l v tr c t cng nht khi bi li trong nc. M mcn tp trung m lin kt, nm gia cc si c.

Vi c gy, hm lng cht bo trong c d tr ch yu trong gan.

II.1.3.2 Dng tnhin trong cht bo

Lipid trong cc loi c xng c chia thnh 2 nhm chnh: phospholipid v

tryglycerit. Phospholipid to nn cu trc mng t bo, v vy chng c gi l lipid cu

trc. Triglycerit l lipid d tr nng lng c trong cc ni d tr cht bo, thng trong

cc t bo mc bit c bao quanh bng mt mng phospholipid v mng li collagen

mng hn. Triglycerit thng c gi l lipid d tr. Mt s loi c c cha cc este dng

sp nh mt phn ca cc lipid d tr.

Thnh phn cht bo trong c khc xa so vi cc loi ng vt khc. im khc nhau

ch yu l chng bao gm cc acide cha bo ha cao. Hm lng acide bo cha bo ha

trong c bin (88%) cao hn trong c nc ngt (70%). Cht bo trong c cha nhiu acide

bo cha bo ha do rt d b oxy ha sinh ra cc sn phm cp thp nh aldehyde, ceton,

skaton. Tuy nhin lipid trong thy sn rt c li cho sc kho ngi tiu dng. Cc hp cht

c li trong lipid c l cc acide bo khng no cao, c bit l: acide eicosapentaenoic (EPA

20.5), v acide docosahexaenoic (DHA 22.6).

im ng c ca du c thp hn ng vt khc. nhit thng trng thi

lng, nhit thp bng c mc khc nhau.


11/32


II.1.4 Glucid

Hm lng glucid trong ctht c rt thp, thng di 0,5% tn ti di dng nng

lng d tr glycogen. Tuy nhin hm lng glycogen cc loi nhuyn th chim khong3%. C va trng lng glucid d tr rt th p. Sau khi cht, glycogen c tht chuyn

thnh acide lactic, lm gim pH ca ctht, mt kh nng gi nc ca ctht. S bin i

ca pH ctht sau khi cht ca c c ngha cng ngh rt ln.

II.1.5 Cc loi vitamine v khong cht

C l ngun cung cp chnh vitamine nhm B (thiamin, riboflavin v B12), vitamine A

v D c ch yu trong cc loi c bo. Vitamine A v D tch ly ch yu trong gan,

Vitamine nhm B c ch yu trong ctht c.

Vitamine rt nhy cm vi oxy, nh sng, nhit . Ngoi ra, trong qu trnh ch bin

nh hng ln n thnh phn vitamine. V vy cn phi ch trnh tn tht vitamine

trong qu trnh ch bin.

Cht khong ca c phn b ch yu trong m xng, c bit trong xng sng.

Canxi v phospho l 2 nguyn t chim nhiu nht trong xng c. Tht c l ngun giu st,

ng, lu hunh v iod. Ngoi ra cn c niken, coban, ch, asen, km.Hm lng cht st trong tht c nhiu hn ng vt trn cn, c bin nhiu hn c

nc ngt, ctht c mu sm nhiu hn tht c mu trng.

Sunfua c ph bin trong tht cc loi hi sn, chim khong 1% cht kh ca tht.

Sunfua trong tht c phn ln tn ti dng h p cht hu c sunfua ha tan. Hm lng

sunfua nhiu hay t c nh hng ln n mu sc sn phm.

Hm lng ng trong c t hn so vi ng vt thy sn khng xng sng.

Hm lng iod trong tht c t hn so vi ng vt hi sn khng xng sng. Cbin c hm lng iod cao hn c nc ngt. Hm lng iod ca hi sn ni chung nhiu

hn gp 10 50 ln so vi ng vt trn cn. Tht c c nhiu mth hm lng iod c xu

hng tng ln.

II.1.6 Tnh cht vt l ca ng vt thy sn

II.1.6.1 Hnh dng


12/32


13/32


II.1.7 Tnh cht ha hc thkeo ca ng vt thy sn

Ch yu nghin cu h thng keo, l cc loi protein .

Do cu to t nhng hp cht nitrogen, cc hp cht ny cu to nn cquan ca c,to cho cu trc ca c c chc, n hi, do dai nht nh (cu to t nhng thnh

phn phc tp nhng ch yu l protein). Cu to ca cth c l mt hn hp nng lng

cht ha hc m trc ht l cc loi protein, sau l lipid, ri n cc mui v c v

nhng cht khc na to thnh mt dung dch keo nht trong nc l dung mi.

* Trng thi tn ti ca nc

Tn ti 2 trng thi l nc kt hp v nc t do.Nc t do: l dung mi tt cho nhiu cht ha tan ng kt 00C, kh nng dn in

ln, c th thot ra khi cth ca sinh vt p sut thng.

Nc kt hp: khng l dung mi cho cc cht ha tan, khng ng kt, kh nng dn

in nh, khng bay hi p sut thng.

* Hnh thc tn ti ca nc

Tn ti di 2 dng hnh thc l ht thn nc v cht thn nc.

- Ht thn nc: tn ti di dng nc khuch tn, nc t do, nc hp ph.

+ Nc hp ph: l lp nc bn trong, kt hp vi cc ht thn nc bng lc

phn t trn b mt hoc mt gc nht nh no .

+ Nc khuch tn: l lp nc gia, khng kt hp vi cc ht thn nc,

dy lp nc khuch tn dy hn lp nc hp ph rt nhiu.

- Cht thn nc: tn ti di 2 hnh thc nc kt hp v nc t do.

+ Nc kt hp gm:

Nc kt hp vi protein dng keo c tc nc do protein dng

keo c hp th.

Nc kt hp protein keo tan: l nc kt hp vi protein trng thi

ha tan, mui v c v cc cht trng thi keo ha tan khc, nc ny l

nc do keo ha tan hp th.

+ Nc t do gm: nc cnh, nc c kt cu t do v nc dnh t.


14/32


Nc cnh: l nc cha rt nghim ngt trong kt cu hnh li, n

l mt dng keo c, nc ny rt kh p ra.

N

c kt c

u t

do: t

n t

i

nh

ng l

nh

v ke h

ca k

t c

u hnh

li ca mng si choc nhng t chc xp nhiu l rng ca m lin kt,

nc ny d p ra.

Nc dnh t: r mng thng dnh st trn b mt ca ctht c.

Nc kt hp c ngha rt quan trng trong s sng ca ng vt thy sn. Bn

cnh nc kt hp cn to gi tr cm quan cho ng vt thy sn, to mi v thm ngon.

II.2 Mui n

II.2.1 Thnh phn muin

Thnh phn ca mui ch yu l NaCl, ngoi ra t nhiu u c tp cht. Nhng tp

cht c th chia lm hai loi:

+ Nhng cht khng c hot tnh ha hc nh nc v cc cht khng ha tan nh

si, ct ,v.v.

+ Nhng cht c hot tnh ha hc nh: hp cht Clor ca Ca

2+

, Mg

2+

, Fe

2+

, Fe

3+

vmui ca gc sulfat.

Mui n tnh khit l cht kt tinh, khng mu. Khi lng ring d = 2.161, im

nng chy: 8030C, im si 14390C.

Mui n c mu trng, tan trong nc, glycerin, hi tan trong cn, d ht m, c v

mn.

Lng nc trong mui lun thay i. Nu trong khng kh c m trn 75% mui

s ht nhiu nc. Nu m khng kh di 75% th mui s kh rt nhanh. Ngoi ralng nc trong mui cn ph thuc vo to nh ca ht mui, ht mui to c hm lng

nc t hn ht mui c tinh th nh.

II.2.2 Cc tnh cht ca muin

II.2.2.1 Tc dng phng thi ca mui n

Mui n thm thu vo nguyn liu lm cho nc thot ra, vi khun thiu nc khng

th pht trin c.


15/32


NaCl khi ha tan s cho raion Cl-, Cl- kt hp ci protide mi peptide lm cho cc

men phn hy protide ca vi sinh vt khng cn kh nng ph vprotide ly cht dinh

d

ng

sinh s

ng. C

ng c th

do ion Cl- c

c tnh lm cho vi khun trng

c.

Nng mui cng ln th p sut thm thu cng mnh, v vt c th lm rch mng

t bo vi khun, gy cho chng st thng.

Do c mui nn oxy t ha tan trong mi trng p mui. V vy nhm vi sinh vt

hiu khi khng c iu kin pht trin. Gii hn pht trin ca khun ln men nng

mui 15% v ca kha ln mc l 20 30%.

II.2.2.2nh hng ca cc thnh phn khc trong mui n

Trong mui n, ngoi NaCl cn c cc mui khc nh CaCl2, MgCl2... Cc mui nyu lm trngi tc thm thu ca NaCl vo cth c, v ha tan ca chng ln hn.

Ngoi ra, cn lm cho mu sc, mi v v vng chc ca sn phm km i.

II.2.2.3 Tnh thm thu v khuch tn

Do tnh ht nc ca mui nn p c vi mui, nc trong c thot ra lm tan

mui (gi l qu trnh khuch tn). Song song l qu trnh mui thm vo c (gi l thm

thu). Sau cng nc t c khng thot ra na nhng mui trong dung dch mui c (nc

bi) vn tip tc ngm vo c th c cho n khi bo ha mui. bo ha mui cthng thp hn nc bi.

C cng ti th tc thp mui cng nhanh v nhiu hn c n.

II.2.3 Cc phng php p mui

II.2.3.1 p mui kh

Dng nguyn ht mui p c. Thng s dng nguyn tc: mui to p c ln,

mui nhp c nh. Do mui ht to tan chm thm t t vo c nhng thm su cho nnc to c thm mui u. Cn mui ht nh mn tan nhanh, thm nhanh vo c, do c

nh con c thm mui u hn.

II.2.3.2 p mui nc

Mui c pha thnh dung dch p c, vi 3 dng nh sau:

+ Dung dch mui lt: c t 15 190B, ha tan t 180 250 gram.

+ Dung dch mui va: c t 20 - 220B, ha tan t 265 300 gram


16/32


+ Dung dch mui mn: c t 23 - 220B, ha tan t 333 350 gram

II.2.3.3 p mui hn hp

y v

a s

d

ng

p mu

i kh ln c, v

a cho vo dung dch n

c mu

i m

n

p mui mt cch lin tc trong dy chuyn sn xut cng nghip.

III. Quy trnh sn xut

C + mui

(2 ngy)

Ln men (6 12 thng)

chp chn

Chit rt Nc mm ct

Xng tht cha thoi ha

Ln men ln 2 (6 12 thng) dch mm

Nc mui B sau chit rt

B Ln men nhiu ln

Dch nc mm

Phi trn

Nc mm thnh phm


17/32


IV. Csl thuyt

IV.1 Bn cht ca cc qu trnh sn xut nc mm

C + mui Nc mmBn cht ca qu trnh ny chnh l qu trnh thy phn protein trong c nh h

enzyme protease pepton polypeptide peptide acide amin.

Qu trnh thy phn protein n acide amin l mt qu trnh rt phc tp. c hiu

ca enzyme l ch tc dng ln mt vi cht no vi vi kiu lin kt nht nh, nh

enzyme peptidase ch tc dng ln mi lin kt peptide thy phan mi lin kt ny:

CO NH H20, peptidase COOH + NH2

Vi d tham gia ca enzyme trong qu trnh thy phn theo cch xc tc:E + S ES E + P

Vi E: Enzyme

S: ccht (protein)

ES: hp cht trung gian gia enzyme v ccht

P: sn phm

Sn phm ch yu ca qu trnh phn gii protein l acide amin v cc peptide cp

thp.

S to thnh v chuyn bin hp cht ES qua 3 bc:

+ Bc 1: Enzyme kt hp vi protein to thnh phc cht enzyme protein, bc ny

xy ra kh nhanh, lin kt khng bn.

+ Bc 2: Xy ra s chuyn bin ca cc phn t prtein dm n lm ph vcc mi

lin kt ng ha tr tham gia vo phn ng. Khi , phc cht ES ng thi xy ra hai qu

trnh l s dch chuyn thay i electron, dn n s cc ha ca mi lin kt tham gia vo

phn ng v bin dng hnh hc ca mi lin kt ng ha tr trong phn t protein cng nh

trong trung tm hot ng ca enzyme, lm cho protein hot ng, qu trnh thy phn d

dng hn.

+ Bc 3: Giai on to thnnh cc acide amin v peptide c p th p, gii phng

enzyme.

Theo nghin cu ca Beddow, ba bc to thnh v chuyn ha hp cht ES tng

ng vi 3 chng ng bin i hp cht nitrogen trong qu trnh thy phn c.


18/32


+ Pha 1 (0 25 ngy): c s gia tng th tch ca phn cht lng ni trn b mt sn

phm v protein ha tan.

+ Pha 2 (80 120 ngy): m t

bo b

ph v

, protein c

a t

bo tr

nn tip xc v

i

enzyme, sn phm ca qu trnh t phn protein c phng thch. hu nh tt c m t bo

u b phn hy v bin mt sau 120 140 ngy.

+ Pha 3 (140 200 ngy): enzyme phng thch v tn cng vo cc phn protein ha

tan. y l nguyn nhn lm thay i hp cht nit.

Ngoi ra, ng v cht bo cng b phn gii thnh ru v cc acide hu c.

IV.2 Cc h enzyme trong sn xut nc mm

Gm 3 h enzyme ln:

IV.2.1 Henzyme Metalo protease (aminodipeptidase)

H enzyme ny tn ti trong ni tng ca c v chu c nng mui cao nn ngay

tu n hot ng mnh, gim dn t thng th ba trv sau. Loi enzyme ny c hot

tnh kh mnh, c kh nng thy phn rng ri i vi cc loi peptide. y l nhm thy

phn enzyme trung tnh, pH ti thch = 5 7, pI = 4 5. N n nh i vi ion Mg2+, Ca2+

v mt hot tnh vi Zn

2+

, Ni

2+

, Pb

2+

, Hg

2+

...

IV.2.2 Henzyme serin protease

in hnh l enzyme tripsin, tn ti nhiu trong ni tng ca c. giai u ca qu

trnh sn xut nc mm hot ng ca n yu n thng th hai v pht trin dn t cc

i thng th 3 ri gim dn n khi chp chn (protein phn gii gn nh hon ton

khng cn dng pepton). H enzyme ny lun bc ch bi chui acide amin trong cu

trc ca enzyme. tho gchui ny phi nhn hat ng cuae men cathepsin B nhng

men cathepsin B s bc chnng mui cao. V vy, men cathepsin B hot ng

c, ngi ta thc hin cho mui nhiu ln. Enzyme serin protease hot ng mnh t

pH = 5 10, mnh nht pH = 9.

IV.2.3 Henzyme acide protease

C trong tht v ni tng c, in hnh l enzyme cathepsin D. H enzyme ny d b

c ch bi nng mui khong 15% nn thng n chit tn ti mt thi gian ngn u


19/32


thi k ca qu trnh thy phn. Loi men ny ng vai tr th yu trong qu trnh sn xut

nc mm.

IV.3 Vi sinh vt trong sn xut nc mmNgun gc: c t nguyn liu, dng c, thit b, mi trng (khng kh, nc). Khi vi

sinh vt xm nhp vo chp c cc nh hng sau:

Tham gia vo qu trnh thy phn protein nhng rt yu v bc ch bi nng

mui cao.

Tham gia tch cc vo vic hnh thnh hng v ca nc mm, ch yu l cc vi sinh

vt k kh c kh nng sinh hng.

IV.4 Nhn tnh hng n qu trnh ch bin nc mm

IV.4.1 Nhit

Nhit tng vn tc phn ng tng, n mt nhit no s khng tng na v

c th gim xung do nhit cao lm cho h enzym serin-protease mt hot tnh. Qu trnh

thy phn km.

+ Nhit 30 470C thch hp cho qu trnh ch bin chp.

+ Nhit 70

0

C trln hu ht cc h enzym trong c mt hot tnh.Nng nhit ca chp ln bng cch phi nng, nu hoc s dng tn nng che

phn xng.

IV.4.2 pH

Mi h enzym c pH ti thch khc nhau, v vy phi xem loi enzym no nhiu nht

v ng vai tr ch yu nht trong qu trnh sn xut nc mm to pH thch hp cho

enzym hot ng. Qua thc nghim cho thy:

pH mi trng t nhin t 5.5 6.5 enzym tripsin v pepsin hot ng c, ng

thi pH ny c tc dng c ch mt phn vi khun gy thi. V vy mi trng t nhin

c pH thch hp cho qu trnh sn xut nc mm hn.

IV.4.3 Lng mui

Mui l nguyn liu quan trng cho qu trnh sn xut nc mm, thiu mui nc

mm khng hnh thnh c.


20/32


21/32


Nh vy tng din tch tip xc s dng phng php p dp kt hp vi nh

khuy chp l tt nht.

IV.4.5 Bn thn nguyn liu

Nhng loi c khc nhau, thnh phn ha hc v cu trc cng khc nhau, nht l h

enzym trong c v vy to ra loi nc mm c cht lng khc nhau.

- C ti ch bin cht lng tt hn c n.

- Loi c c kt cu c tht lng lo, mm mi, t vy d ch bin hn loi c cng,

chc, nhiu vy.

- Nu c c nhiu m th nc mm c mi i kht kh chu, mi chua (do s thy

phn cht bo thnh acid bo v glycerid) hoc kht do oxy ha cht bo.

- C sng tng nc mt v gia nh c thu, c cm, c nc, c mi... cho cht

lng nc mm tt nht v n n c thc n ngon nn dinh dng v thnh phn m

cao.

- C sng tng nc di v tng y nh c phn, c mi cho nc mm c cht

lng km v thiu thc n (n rong, ru, bn hoc thc vt di y) lm cho tht c thiu

dinh dng v bng c c bn t nh hng n mu sc nc chp

V. Thuyt minh quy trnh

V.1 Xl nguyn liu

V.1.1 C

Nu c chp thuc loi c tp, kch thc ln v nhiu du nh c Linh, c trch...

th cha trong cc h ngoi tri. l h xi mng c kh nng gi nhit tt. Khi t ngoi

tri, n hp thu nhit mnh v phn gii tht c. Cng dng ca vic s dng h ngoi tri

cho mt s loi c nh sau

- i vi c tp: do cht lng c khng tt, nu ch bin trc tip th nc mm

khng ngon mc d lng m c th cao. V th, h cha c tp ch yu l to h thng ly

m cho nc mm.


22/32


- i vi c c kch thc ln: nhh c khng gi nhit, nhit cao nn qu

trnh phn gii c nhanh hn so vi vic phn hy c nhit thng chp bng g trong

nh liu.

- i vi c du: du c trong qu trnh ch bin rt d b oxy ha nn cng nh

hng n cht lng nc mm. V vy, ngi ta tr c trong cc h ngoi tri va trnh

lm gim cht lng nc mm, va c th vt du bn, tng thm thu nhp.

Nguyn liu sau khi tip nhn phi c ra sch, loi b tp cht v chun b ch

bin.

V.1.2 p mui

Trc khi ch bin, phi tin hnh v sinh thng chp v tnh ton lng mui cho

vo khi chp.

Cho c v mui vo thng. C mt lp c th mt lp mui v dng bn co g

dn u lp c v lp mui. Nn ri nhiu lp mui mng thay v t lp nhng dy. Ph mt

lp mui mt kh dy khong 2 3 cm trn cng. Mc ch l gi nhit v trnh rui nhng

u vo.

Ly nhiu lp l ph ln lp mui mt. Lp l c ct cht vo cc thanh np, dngcc n h gi cc thanh np li ri dng hai n thng gc ngang qua thng chp nn

v khng b tri ln. Mc ch ca khu gi nn l va gic v sinh, va tc dng lc p

nc t tht c c tit nhanh hn.

V.2

Thi gian: 2 ngy.

y l giai on ln men kh, c khi chp nng ln n gn 400C.

Ln men kh ym kh va c tc dng phn gii tt, va to hng v thm ngon.V.3 Giai on ln men - ch bin chp c truyn

y chnh l qu trnh thy phn protein trong c nhh enzyme protease. Sn phm

cui cng l acide amin hoc peptide cp thp.

C 3 phng php ch bin chp c truyn:

- Phng php nh khuy:+ y l phng php ca Ct Hi - Hi Phng.


23/32


+ Cho mui nhiu ln li dng c kh nng phn gii ca enzyme v vi sinh

vt ti mc cao, rt ngn thi gian ch bin chp. Cho mui nhiu ln l to

iu ki

n

phng th

i, tiu di

t cc vi khu

n gy th

i thng th

ng v khng

km hm nhiu qu kh nng hot ng ca men.

+ Cho thm nc l l cung cp cho mi trng phn gii mt lng vi sinh vt

ng k, to mi trng lng gip cho men v vi sinh vt hot ng c d dng,

lm cho t bo tht c chng c phn gii.

+ Lng nc cho thm vo nn va phi, nu t qu th tc dng phn gii ca

men km nhng nu nhiu qu th khng khng chc qu trnh thi ra, ng

thi lm gim m trong nc mm. V vy, lng nc cho vo cn ty thucc im ca nguyn liu, thng t 20 30% so vi c.

- Phng php gi nn:+ C c trn u vi mui cho mui ngay tu hoc cho mui nhiu ln,

sau p vo thng hoc b ri gi nn. Da vo men trong c phn gii

protide ca tht c, khng cho nc l v khng nh khuy.

+ y l phng php ca vng khu 4 c hoc ca cc tnh pha Nam.

- Phng php ch bin h hp (kt hp hai phng php gi nn v nh khuy)+ Phng php ny rt kinh nghim t hai phng php trn

+ Lc u, thc hin phng php gi nn.

+ sau thc hin phng php nh khuy.

min Nam, ch bin chp theo phng php gi nn th thi gian di nht nhng

ni chung m thi t hn nn m hu t trong nc mm cao hn v tng lng m cng

cao hn so vi phng php nh khuy.

Khi cho mui th thn c ngm mui, nt u v chm xung, khng cn

hin tng trng v ni ln na. Lc , ngi ta ni c ng c. Nhnn cht, nhit

ni c trong c lm cho men hot ng tng ln, trung tm tch t dn kh Nh3, CO2, H2S...

lm cho c trng ln, tht c b x nt nhng xng v da vn cn nguyn. Mui thm thu

vo c nc tit ra gi l nc bi. Khong 1 thng sau th c chm xung hn, nc ni ln

c mu vng, trong v xut hin mi nc mm r rt, lc c ng mt du. Mu

sc ca nc mm chuyn t mu vng nht sang hn mu vng m, nc mm trong.


24/32


Sau 6 12 thng, chp chn hon ton, c th chit rt.

c im ca phng php ny l chp chn c vn cn nguyn con, xng khng

nt nn thun l

i cho vi

c ko rt.

V.4 Chit rt

Qu trnh ko rt nc mm l qu trnh lc lin hon. Qu trnh ko rt l qu trnh

rt m trong b khng qu nubng cch dng lng nc bi hoc nc thuc t m cho

chuyn ln lt t thng ny qua thng khc tng m v tng hng v.

Sau khi chp chn, nc mm ch c mi thm thun ty, khng cn mi hn tp

ca chp na. Tuy vy, phn b vn cn mi tanh. Ta rt phn nc c nu vng, trong

pha trn (nc mm ct).Cn li phn xng tht c cha phn gii ht ta tip tc cho ln men. Vi mi ln

chit rt ta li b sung nc mui vo lm nc thuc. Qu trnh ln men tip tc phn

gii ht lng tht c cn st li.

Qu trnh ln men v chit rt dng li khi tt c tht c hon ton c phn gii.

V.5 Phi trn

Mun thu c nc mm c hng v thm ngon v c nng m nh mong

mun, ta phi pha u cc loi noc mm c m khc nhau, thng pha nc mm cm cao vi nc mm c m thp thnh loi nc mm c m trung bnh. Vic

tnh ton th tch c thc hin theo qui tc ng cho.

Gi s ta c 2 loi nc mm: mt loi A0N, mt loi B0N, pha ch thnh nc mm

150N. Cng thc pha u cho:

VI. Nhng hin tng hhng ca chp

VI.1 Chp chua

- Hin tng: chp bc mi chua, mu xm m mi tanh hi kh chu.

- Nguyn nhn


25/32


+ Chua v mn u: do lng mui lc u qu nhiu, lng mui ny ngm vo lp

tht c pha bn ngoi, bn trong v ni tng cha kp ngm mui lm cho tht c b nht

mui, x

y ra qu trnh phn gi

i sinh ra nhi

u acid bay h

i ph

c t

p nh

: glycogen, glucose

b phn gii ym kh to ra acid lactic.Cc cht ny phn gii hiu kh to acid acetic, acid

butyric. Ngoi ra cc cht bo b thy phn to glycerin v acid bo hoc cht m kh amin

thnh acid bo.

+ Chua v nht u: c nht mui khng sc kim hm s pht trin ca vi sinh

vt, phn gii to nhiu acid bay hi phc tp lm pht sinh mi chua, tanh thi nhanh chngchuyn sang h thi.

- Cch phng cha

+ Cn phi cho mui u v .

+ No o, phi nng v ko rt qua b chp tt.

+ Dng ru chuyn cc acid sang dng ester c mi thm hoc trung ha bng

NaHCO3.+ Dng thnh hp ph mi.

+ Chua v mn u tin hnh cho thm nc l vo trong chp v tin hnh ch bin

chp tip theo.

VI.2 Chp en

- Hin tng: nc b xm en, c nht nht v mc cao hn na l c ben.

- Nguyn nhn

+ Do c c bn t tp cht khng nhng mang, nht bn ngoi m ngay ni tng

ca c.

+ Do cc sc t c trong da, tht v ni tng ca c nh: Lutein, astaxanthin,

taraxantin v nhng dn xut khc nh: sepiamelanin c trong mc.

+ Do s phn hy ca cc cht khc.

+ Do trn mui khng u gy ngng t nhm amin v nhm aldehyde.


26/32


+ S oxy ha cc cht bo cha bo ha.

Nhng cht gy en phn ln c cha S, khi phn hy c th hnh thnh H2S, CH3-

HS cho mu

en, nh

ng cht ny tc d

ng v

i ion kim lo

i c

ng cho mu

en.

- Cch phng cha

Ty theo nguyn nhn c cch phng cha khc nhau.

+ X l nguyn liu ban u cho tt.

+ Cn chn la nguyn liu ban u cho k, trnh nhim bn.

+ Cho mt t thnh rang k v b chp tt vo trong b chp ben, tin hnh nh

khuy v tng cng phi nng.

+ Dng cht chng oxy ha KMnO4, KClO3, H2O2 oxy ha cc cht en.

+ Khi chp trmi kp thi cho mui vo ngn chn s pht trin ca vi sinh vt.

+ un si nc bi, mu en s b ph hy do bay hi, vi sinh vt b tiu dit.

VI.3 Chp thi

- Hin tng: chp thi bao gicng en v c mi hi thi nhng chp en cha chc

thi.

- Nguyn nhn:

Ch yu do mui qu nht hoc sau khi c i mui ta khng kp thi cho mui vo.

Khi cc vi sinh vt hot ng phn hy cc cht c m ch yu l cc acid amin thnh

cc sn vt cp thp lm cho chp b thi.

- Cch phng cha

+ Cn x l nguyn liu cho tt trnh nc ma vo.

+ Dng c ch bin phi sch s, khng chp ni m thp, bn thu.

+ Cn p dng ng k thut ch bin, ng thi cn nm vng hin tng c i

mui cho mui , ng v kp thi.

Nu chp b thi ri rt kh cha.

+ C th trn vi chp khc v em nu.

+ Chp b nc ma nhiu vo th c th mc ring phn ra cho mui vo, tng

cng phi nng no o.


27/32


VI.4 Nc mm thi v cch phng cha

- Hin tng: nc mm thi ni ln nhng bt nh v dn dn nc bc, c mu nu

xm

n xanh v xng ln mi hi th

i.

- Nguyn nhn:

+ Chp cha chn ch mi phn gii n sn vt trung gian d bng vn, keo t

m ta em ko rt.

+ Do nc mm lc khng trong (cn li xc c).

+ Do nc hm b nht mui hay qu nng to nhit v mi trng thch hp cho

vi sinh vt pht trin.

+ Do b thng lc hoc dng c cha khng sch s c khi ln c xc chp sng.+ Do nc mm b nc ma hay nc l vo.

- Cch phng cha:

+ Cn trnh nhng nguyn nhn trn.

+ Cch cha duy nht hin nay l dng nhit lm bay hi mi hi thi.

VII. Cc ch tiu phn loi, kim tra chp nc mm

VII.1 Phn loi chpChia lm 3 loi

- Chp loi A: gm tt c cc loi chp ca c ni nh: c cm, c nc, c linh. Chp tt

loi ny dng sn xut nc mm thng hng.

- Chp loi B: gm cc loi chp ca c ni c cht lng km hn v cc loi chp ca

c khc c cht lng tt. Chp ny dng sn xut nc mm c bit v loi I.

- Chp loi C: l chp ca nhng loi c y c cht lng xu nh c phn, c mi...

VII.2 Ch tiu nh gi chp chn

VII.2.1 Cm quan

- Mu sc: mu nu ti, nu xm hoc xm. Ring nc ct c mu vng rm n cnh

gin.

- Mi thm c trng, khng c mi chua, mi l.

- Trng thi


28/32


+ i vi chp gi nn: c cn nguyn con, nu s ra tht c tch khi xng, nu

khuy tht s nt vn.

+

i v

i ch

pnh khu

y: c nt nhuy

n, ci ch

p sng, khi

nh khu

y khng

c hin tng si bt.

VII.2.2 Ha hc: c 2 yu t

T l nitamin trn m ton phn ca nc ct.

+ i vi chp c ni t l ny > 45%.

+ i vi chp c y t l ny > 40%.

* Mt vi phng php khc

- Phng php phi nng hoc sy 500

C, nu nc mm khng c bin i g sovi mu i chng l nc mm chn. Nu mu t vng rm hoc cnh gin chuyn sang

vng nht mt hng vc trng, vn c th chp cha chn.

- Phng php lng ng: ngi ta s dng phng php chc lc mnh mu nc

mm, lc 30-40 ln sau yn 20 pht, nu mu nc mm khng c bin i g so

vi mu i chng l chp chn.

VII.3 Tiu chun ca nc mm thnh phm

Bng 4. Tiu chun nh gi cht lng nc mm

LoiCh tiu c bit (g/l) Loi 1 Loi 2

Nittng s 20 15 11

Nitamin 8,5 6,5 4

Nitamoniac


29/32


VIII. Gi tr dinh dng ca nc mm

VIII.1 Cc cht m

Chim ch yu v quyt nh gi tr dinh dng ca nc mm. Gm 3 loi m:- m tng s: l tng lng nitc trong nc mm (g/l), quyt nh phn

hng ca nc mm.

- m amin: l tng lng m nm di dng acid amin (g/l), quyt nh gi

tr dinh dng ca nc mm

- m amon: cng nhiu nc mm cng km cht lng

Ngoi ra trong nc mm cn cha y cc acid amin, c bit l cc acid amin

khng thay th: valin, leucin, methionin, isoleucin, phenylalanin, alanin.v.v .. Cc thnhphn khc c kch thc ln nh tripeptid, peptol, dipeptid. Chnh nhng thnh phn trung

gian ny lm cho nc mm d b h hng do hot ng ca vi sinh vt.

Thnh phn dinh dng ca nc mm ph thuc vo nguyn liu em i ch bin.

VIII.2 Cc cht bay hi

Rt phc tp v quyt nh hng v ca nc mm.

Hm lng cc cht bay hi trong nc mm mg/100g nc mm

- Cc cht cacbonyl bay hi: 407-512 (formaldehyde)

- Cc acid bay hi: 404-533 (propionic)

- Cc amin bay hi: 9,5-11,3 (izopropylamin)

- Cc cht trung tnh bay hi: 5,1-13,2 (acetaldehyde)

Mi trong nc mm c hnh thnh ch yu do hot ng ca vi sinh vt ym kh

trong qu trnh sn xut nc mm to ra.

VIII.3 Cc cht khc

- Cc cht v c: NaCl chim 250-280g/l v mt s cc cht khong nh: S, Ca, Mg,

P, I, Br.

- Vitamin: B1, B12, B2, PP.


30/32


Hnh 1: Nc mm


31/32


Hnh 2: Cc thng


32/32

htt // b k d 31

Hnh 3: Nc mm c chit rt

qui-trinh-san-xuat-nuoc-mam

Documents