Vi Sinh Hoc Ung Dung

8/9/2019 Vi Sinh Hoc Ung Dung

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TRNG AI HOC A LAT

GIAO TRNH

VI SINH HC NG DNGGiang cho SV nam th ba - Nganh Sinh Hoc

(SH 235 30 tiet)

ThS. BCH PHNG LAN

2004


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Vi sinh hoc ng dung 1 -

MUC LUCMUC LUC ................................................................................................................. - 1 -Li tac gia.................................................................................................................. - 3 -CHNG 1. SAN XUAT SINH KHOI NAM MEN VA SINH KHOI VI TAO.......- 4 -

I. GIA TR DINH DNG CUA NAM MEN .....................................................- 4 -II - NHAN GIONG VA GI GIONG NAM MEN................................................- 6 -III- KHAO SAT CAC CH TIEU SINH HOC CAN THIET ................................. - 8 -

1. Hoat tnh nhan len: The hien qua mc tang sinh khoi tong cong, c anh giaqua 3 ch tieu: ....................................................................................................- 8 -2. Hoat tnh len men: (bang phng phap Durgham)....................................... - 8 -3. nh lng am Amin trong dch nuoi cay bang phng phap Formol...... - 10 -4.Xac nh hieu qua cua cac tac nhan kich thch QT t phan..........................- 11 -

IV- NG DUNG C CHE T PHAN E SAN XUAT SINH KHOI NAM MEN

DI DANG BOT DINH DNG VA COM BO.............................................- 14 -1. C s ly thuyet.............................................................................................- 14 -2. Quy trnh cong nghe ................................................................................... - 16 -

V - SAN XUAT SINH KHOI VI TAO................................................................- 19 -1. ac iem chung...........................................................................................- 19 -2.Nuoi trong Luc Tao n bao (Chlorella)......................................................- 20 -3. Nuoi trong Tao xoan a bao (Spirulina)......................................................- 20 -

Chng 2. NG DUNG CONG NGHE VI SINH TRONG BAO QUAN VA CHEBIEN THC PHAM................................................................................................ - 22 -

I. O NHIEM THC PHAM VA HAU QUA ....................................................... - 22 -1.Khai niem chung........................................................................................... - 22 -2. Tac nhan gay o nhiem thc pham: .............................................................. - 23 -3 - Nhng benh nhiem khuan do an thc an b nhiem khuan..........................- 24 - 4.C che sinh hoa cua qua trnh gay h hong thc pham................................- 26 -

II. CAC PHNG PHAP BAO QUAN THC PHAM.......................................- 27 -1- Nguyen tac Bioza (Bios = s song) ............................................................ - 28 -2 - Nguyen tac Abioza. (Abiosis = khong song)..............................................- 28 -3. Nguyen tac Anabioza (= giam s song)...................................................... - 30 -

III. S DUNG NHOM NAM MOC TRONG BAO QUAN VA CHE BIEN THCPHAM.................................................................................................................. - 33 -

1. C s sinh hoc cua viec s dung nam moc trong che bien .......................... - 33 -va bao quan thc pham. ................................................................................... - 33 -2.. San xuat nc cham len men t kho dau lac..............................................- 34 -3. San xuat chao t au phu.............................................................................- 39 -

ThS. Bach Phng Lan Khoa Sinh hoc


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IV. KIEM NGHIEM THC PHAM....................................................................- 41 -1.Nhom ch tieu cam quan...............................................................................- 41 -2.Nhom ch tieu hoa ly .................................................................................... - 41 -3.Nhom ch tieu Vi Sinh .................................................................................. - 41 -

4- Y ngha cua cac ch tieu vi sinh...................................................................- 41 - Chng 3. CONG NGHE LEN MEN......................................................................- 44 -I. . LEN MEN ETILIC VA NG DUNG. ........................................................... - 45 -

1. C che ly thuyet cua qua trnh len men Etilic ............................................. - 45 -2 - Phan biet cac dang san pham len men ru...............................................- 46 -3 Quy trnh san xuat bia ai mach................................................................- 46 -4 - Quy trnh san xuat vang nho.......................................................................- 48 -

II . LEN MEN LACTIC VA NG DUNG. ......................................................... - 49 -1. C che ly thuyet cua qua trnh len men Lactic............................................- 49 -

2.Mot so cong thc che bien va bao quan tht, sa, tom bang len men Lactic. - 53-III. LEN MEN ACETIC VA NG DUNG. ........................................................ - 58 -

1. C che ly thuyet...........................................................................................- 58 -2. San xuat dam an: ......................................................................................... - 60 -3. San xuat thach da (Nata de coco) ........................................................... - 61 -

Chng 4. CONG NGHE VI SINH TRONG X LY CAC CHAT THAI...............- 62 - I. X ly nc........................................................................................................- 62 -

1. Khai niem, phan loai, thanh phan hoa hoc cua nc thai........................... - 62 -

2 . Cac ch tieu anh gia chat lng nc thai................................................ - 62 -3. X ly nc thai bang cong nghe vi sinh (CNVS) ........................................ - 63 -II- X ly rac.........................................................................................................- 69 -

1- Phan loai rac thai.........................................................................................- 69 -2 Phan huy cac hp chat hu c cao phan t................................................- 70 -

III . X LY MOT SO CHAT THAI CONG NGHIEP NH VSV.......................- 73 -1. X ly phe thai cua CN che bien sa ........................................................... - 73 -2.- X ly phe thai cua CNSX cac chat tay ra.................................................- 75 -



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LI TAC GIA

Vi Sinh Vat Hoc ng Dung la mot trong 5 mon hoc thuoc he thong cac giaotrnh cua chuyen nganh V Sinh Vat Hoc, tnh theo trnh t thi gian ma sinh vien

nganh Sinh Hoc Thc Nghiem se c hoc la:1. Vi sinh vat hoc ai cng (nam th Hai)2. Vi sinh vat hoc ng dung (nam th ba )3. Vi sinh y hoc va mien dch hoc (nam th t )4. Cong nghe vi sinh (nam th t - t chon)5. Hoat tnh vi sinh vat at (nam th t - t chon)

V the, trong giao trnh nay se khong nhac en nhng kien thc a hoc e cap trong cac giao trnh khac, tr trng hp that can thiet.

ieu kien tien quyet la trc khi hoc giao trnh nay sinh vien a c trang

b nhng kien thc c ban ve Hoa Sinh, Di Truyen, Sinh Ly Thc Vat Va Vi SinhVat.Muc tieu cua mon hoc la giup sinh vien tiep can vi nhieu hng ng dung

khac nhau cua Vi Sinh Hoc trong i song, ong thi tao cho sinh vien co thoiquen lien he gia ly thuyet vi thc hanh bet dung nhng kien thc a hoc ely giai cac hien tng dien ra trong thc tien.

Trong qua trnh giang day, ngoai viec truyen thu kien thc, giang vien sedanh mot ty le thi gian thch hp e ren luyen cho sinh vien mot so ky nang lienquan en mon hoc va en nghe nghiep mai sau v du :

- Ky nang thu thap va x ly tai lieu tham khao e chat loc nhngthong tin cot loi- Ky nang x ly va nhan xet nhng so lieu thu c qua khao sat -

thc nghiem- Ky nang soan thao va thuyet trnh theo chu e (ceminar) v.v

Ve pha ngi hoc cung can phai hp tac chat che vi ngi day, chu ongtham gia vao nhng hoat ong tren lp e co c nhng gi hoc tch cc va boch.

Co the xem nhng hoat ong tren lp la c hoi e sinh vien trau doi kha

nang t hoc, t nghien cu, chuan b tot cho viec vao i trong tng lai.Tac gia xin chan thanh cam n rat mong nhan c nhng y kien ong gopcua cac ban ong nghiep va nhng ai quan tam.

Th.s Bach Phng Lan



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CHNG 1. SAN XUAT SINH KHOI NAM MEN VA SINH KHOI VITAO

I. GIA TR DINH DNG CUA NAM MEN

Co the noi khong mot loai ong vat hay thc vat nao lai cha trong te bao motlng cac chat co gia tr dinh dng phong phu nh trong te bao nam men. Ngi ta cothe tm thay trong sinh khoi nam men tat ca cac thanh phan can thiet cho s song cuacon ngi va ong vat bac cao. Bi vay cac loai san pham dinh dng ieu che t sinhkhoi nam men c xem nh mot thc n ly tng

Nhieu dan lieu ve ty le thanh phan trong nam men cho biet nh sau

- Protein va cac hp chat cha Nit: 40 -60%

- Gluxit 30 -35%

- Lipit 1 - 2%

- Cac chat khac 6 - 7%

Trong thanh phan Protein cua nam men co cha ay u 20 loai axit amin thongthng, bao gom ca 9 loai axit amin khong thay the, chung c phan bo vi mot ty le

kha can oi .

V du: (Tnh theo trong lng kho).

- Lizin 4,4 - 5,7 %

- Methionin 1,2 - 1,8 %

- Sistein 1,2 - 1,8 %

- Treonin 2,8 - 3,6 %

- Tryptophan 0,57 - 0,7 %.

So sanh vi cac loai bot m va bot gao th ty le nay cao hn khoang t 3 - 10 lan

Ham lng vitamin trong te bao nam men cung rat phong phu, ac biet lavitamin nhom B. So vi cac loai au tng, au nanh va au Ha lan th trong te bao



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nam men th ty le vitamin B3 cao hn 5 - 10 lan, ty le vitamin B4 cao hn 4 - 6 lan, tyle vitamin B2 cao hn 20 - 75 lan. Seelay (1981) a a ra nhng dan lieu ve hamlng vitamin trong nam men bia (loai Saccharomyces cerevisiae) nh sau:

- Thiamin (B1) 156,0 mg/Kg trong lng kho.

- Riboflavin (B2) 100,0 -------

- Axit Pantotenic (B3) 100,0 ---- ---

- Axit Cholic (B4) 710,0 -------

- Piridoxin (B6) 020,0 -------

- Niaxin (PP) 022,0 -------

- Axit Folic 013,0 -------- Inoziton 500,0 -------

Ngoai ra con co Esgosterin, mot tien chat cua vitamin D2.

ieu ang chu y la trong te bao nam men co cha mot he enzim noi bao vangoai bao kha ay u, bao gom cac loai quan trong nh: Protease, Pectinase, Amilase,Glucoamilase, Mantase, Lactase... Chnh s co mat cua cac enzim nay a quyet nhcac ac iem sinh hoc ac trng cua nam men - trong o co mot c che se c e cap

en phan sau, o la hien tng t phan cua te bao nam men.Nam men co toc o sinh trng va phat trien manh, thi gian the he trung bnh

la t 30 - 60 phut. Do vay, viec nhan giong e dung trong san xuat rat de dang thuanli .

Trong cong nghe vi sinh, ngi ta thng s dung nam men theo 3 muc ch chu yeu:

1. Thu nhan sinh khoi tong cong (san xuat com bo, bot dinh dng, proteintho)

2. Thu nhan cac san pham len men ( ru trang, ru vang, bia, dch trai cay len men ... )

3. Thu nhan cac san pham sinh tong hp ac trng ( Axit amin, vitamin....)

Di ay chung ta se tm hieu sau hn ve cong nghe thu nhan sinh khoi tongcong.



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II - NHAN GIONG VA GI GIONG NAM MEN

Theo phng phap co ien, te bao nam men dung lam goc giong c gidi cac dang sau:

- Ong giong thach nghieng.

- Giong ong kho dang bot.

- Giong men dang bot quanh (dang past)

T cac giong goc nh tren, trc khi a vao san xuat can tien hanh hoannguyen te bao, tc la cay chung tren moi trng dinh dng dang dch the vi thanhphan dinh dng toi u e a chung tr lai dang hoat ong, phuc hoi hoat tnh giong,sau o t giong a hoan nguyen ngi ta tien hanh nhan giong cac cap I, II, hoac III

(tuy mc o can thiet ve so lng) e co giong san xuat . Bang cac phng phap tren,quan the giong a vao san xuat co dang te bao nam men t do (viet tat laTBNMTD). Khi dung TBNMTD nh vay co nhieu han che :

- Giong de b thoai hoa, giam hoat tnh

- Moi quan the giong ch dung c mot lan .

- Dch len men b uc nhieu, khau lang loc kha cong phu .

Trong nhng nam gan ay, nh nhng tien bo vut bac trong cong nghe sinhhoc, ngi ta a e xuat mot phng phap mi trong viec tao giong nam men - o la kthuat gan te bao nam men tren cac gia the Polymer co phu cac nhom chc hoat ongbe mat. Te bao nam men c gan co nh tren gia the nh vay c goi la quan theTe bao nam men co nh (Viet tat la TBNMC).

Dung TBNMC lam goc giong se khac phuc c cac nhc iem tren, cacmanh gia the cha TBNMC co the tai s dung nhien lan, dch len men thng trong.Khi s dung giong TBNMC trong nhng c s san xuat ln co toc o quay vongnhanh th hieu qua kinh te tang ro ret so vi khi dung phng phap co ien.

Cac loai Polymer thng c dung lam gia the gom 3 loai:

- Polyethylene (PE)

- Polystyrene (PS)

- Polyvinyl chorid (PVC)



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e tao nen hoat tnh be mat cho cac gia the, ngi ta phu tren be mat cua chungmot loai Monomer thch hp nham muc ch e lo ra cac nhom chc -COOH hoac -NH2 hoac OH -. Cac nhom chc nay khi tiep xuc vi quan the te bao nam men se lienket vi cac iem thu the (Receptor) tren mang te bao, nh vay ma te bao nam men co

the lien ket ben tren gia the.Cac Receptor tren mang TBNM thc chat la nhng phan t Protein xuyen mang,

co cac au cha cac nhom chc -COOH hoac -NH2 e lo tren be mat lp mang sinhchat (Membrane). Nhng nhom chc nay tao v tr tiep nhan cho nhng oi tng naoco cac nhom hoat ong tng ng (ma trong trng hp nay chnh la cac manh gia thePolymer a c phu cac Monomer).

Hai loai Monomer thng c dung e phu len be mat cac manh ga thePolymer la:

- Methacrylic acid (MAAc) cha nhom chc Carboxyl (-COOH).

- Acrylamide acid (Aam) cha nhom chc amni (-NH2).

e tao nen cac manh gia the co nhom chc hoat ong be mat can tien hanh congoan ghep Monomer. Co nhieu phng phap khac nhau e ghep, mot trong nhngphng phap co the thc hien kha de dang tai vien Nghien cu Hat nhan (NCHN) aLat la Dung bc xa vi nguon CO 60.

Sau khi a tao c gia the, bc tiep theo la gan TBNM vao gia the. Quy trnhgan TBNMC oi hoi phai thc hien qua nhieu cong oan, vi nhng ieu kiennghiem ngat ve cac mat:

- o trng nc cua gia the.

- o pH va thanh phan dung dch em cua moi trng trong o dien ra qua trnhtiep xuc gia quan the TBNM va gia the.

- Nhiet o va toc o lac can duy tr trong suot thi gian tiep xuc.

- Khoang thi gian can thiet cho qua rnh tiep xuc- Hoat tnh con lai cua TBNM sau khi c gan co nh tren gia the.



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III- KHAO SAT CAC CH TIEU SINH HOC CAN THIET

e tuyen chon goc giong dung trong san xuat, trc het can xac nh Hoattnh sinh hoc chu yeu cua cac chung nam men hien co

Hoat tnh sinh hoc chu yeu cua cac chung the hien qua hai tieu ch sau:

1. Hoat tnh nhan len: The hien qua mc tang sinh khoi tong cong, c anhgia qua 3 ch tieu:

Thi iem sinh khoi at cc ai (tnh bang gi) Lng sinh khoi tong cong tai thi iem at cc ai (tnh bang ch so o o

uc D%)

Mc tang sinh khoi, the hien qua o chenh lech ve ch so o uc gia thiiem at cc ai so vi luc bat au nuoi cay (tnh bang so lan)

2. Hoat tnh len men: (bang phng phap Durgham)

The hien qua ch so sinh CO2, c anh gia qua 2 ch tieu:

Thi iem tao bot kh CO2 au tien (gi). o noi toi a cua phao Durgham (Lf).Giong nam men c dung trong san xuat bao gom 6 chung thuoc giong

Saccharomyces cerevisae

Nhng phng phap dung trong khao sat:

a. Th kha nang len men cua giong goc bang phng phap Durgham:

Nguyen tac:

Da vao lng CO2 thoat ra trong qua trnh nuoi cay e anh gia toc o len mencua quan the te bao.

Cach tien hanh:

Chon mot loat cac ong nghiem co o day ong nhat va co dung tch bangnhau, tren thanh ong a co vach chia o.



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Cho vao moi ong 5ml moi trng Hansen. Tha vao ay moi ong mot chiec phao Durgham (phao Durgham at mua cua

Vien Vaccin a Lat).

Cay mot lng xac nh giong te bao nam men vao cac ong, duy tr nhiet ot 30 - 320C. Theo doi cac ch tieu:

Thi iem tao bot kh CO2 au tien. o noi toi a cua phao Durgham (c ky hieu la Lf).

b. So o uc tren may so mau quang phohap phu (Electrophotometre)

Nguyen tac:

o uc cua dch nuoi cay se phan anh lng sinh khoi tong cong co trongmoi trng.

ng vi moi thi iem can khao sat, lay mau e o o uc tren may, tnhmc chenh lech ve o uc e biet mc o tang sinh khoi.

Cach tien hanh:

Hon dch nam men nuoi cay tren moi trng Hansen c pha loang en opha phu hp cho viec s dung may. o mau a pha loang vao Cuvet, a vao may.

Cho anh sang co bc song 520 i qua dung dch. Chum tia sang gap dungdch se b hap phu mot phan va b tan xa, ch co mot phan xuyen qua. Kim ong ho chobiet phan anh sang a b ngan can khong i qua hon dch. Bang cach nay chung ta biet

c o can quang cua dung dch, tnh theo %, c ky hieu la D - o cung chnhla Ch so o uc cua quan the te bao. o uc cang cao chng to lng sinh khoi cangln, so te bao trong quan the cang nhieu.



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3. nh lng am Amin trong dch nuoi cay bang phng phap Formol

(lng am Amin ty le thuan vi lng sinh khoi, ong thi phan anh chat lngdinh dng cua dch sinh khoi)

Muc ch:

Xac nh lng am co mat trong dch sinh khoi di dang cac axit amin t do.

Nguyen ly: Nit co the phan ng vi formol trong moi trng kiem e hnhthanh dan xuat Metylen - Aminoaxit khien cho nhom chc Carboxyl trong phan tc boc lo chc nang axit lam cho moi trng mang tnh axit. Dung NaOH chuano e t o suy ra lng axit amin co trong moi trng.

Cac phan ng: ( xay ra ieu kien pH = 9 )R - CH COOH + H C = O R CH COOH + H2 O

NH2 H N = CH2

R CH COOH + NaOH R CH COONa + H2 O

N = CH2 N = CH2

Cach tien hanh:

Bo tr song song mot bnh th nghiem (TN) va mot bnh kiem tra (KT).

Bnh TN:

Hut chnh xac 10ml dch sinh khoi nam men cho vao bnh tam giac. Them 5ml formol, nho vai giot phenolphtalein e lam ch th mau. Lac eu bang may khuay t t cho en khi kim ch pH on nh. Nho t t tng giot NaOH 0,1N cho en khi co mau hong nhat (ng vi pH

8,8). Lac eu, nho tiep NaOH 0,1N cho en khi co mau hong am va ben (ng vi pH9 - 9,1).



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Dung HCl 0,1N chuan o ngc tr lai cho en pH trung tnh. Bnh KT:

Thay hon dch sinh khoi bang 10ml nc un soi e nguoi. Thao tac tng tnh tren .

Lap lai th nghiem 3 lan. Ket qua c tnh theo cong thc:

( )

( ) ( )[ ]N

V V V Va

x xmg%

' '

,= 1 2 1 2

14 100

Trong o: V1: Tong lng NaOH 0,1N dung e chuan o bnh TN.

V2: Tong lng HCl 0,1N dung e chuan o bnh TN.V1: Tong lng NaOH 0,1N dung e chuan o bnh KT.

V2: Tong lng HCl 0,1N dung e chuan o bnh KT.

a: Lng mau dung e chuan o.

4.Xac nh hieu qua cua cac tac nhan kich thch QT t phan

Th nghiem hai loai tac nhan, vi 2 nong o tng ng, a c nhieu tac gia

tha nhan la co hieu qua cao nhat, o laNaCl 5% va Toluen 1%.

Dch sinh khoi cua chung giong NM sau 18 gi nuoi cay tren moi trng ncchiet t nhien, c thu lai e trong 9 bnh cau, moi bnh cha 1 lt hon dch, chia lam 3lo, moi lo 3 bnh:

Lo TN1: Cho tiep xuc vi NaCL 5%. Lo TN2: Cho tiep xuc vi Toluen 1%. Lo C: Khong cho tac nhan (oi chng).Duy tr 400C, lac 150vong/phut. Hieu qua cua qua trnh t phan c anh gia

qua ch so va ham lng am amin trong hon dch. Tai cac thi iem cach eu laymau e nh lng am amin. (xem bang 1)



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Bang1: So sanh hieu qua cua 2 loai tac nhan kch thch t phan c dungtrong khao sat.

Thi iem Ham lng am amin ( mg/100ml )lay mau

(gi)Dung NaCl

5%DungToluen

1%oi chng

0 73,05 73,05 73,05

5 80,60 79,40 78,20 *

10 76,20 67,90 67,90

15 67,90 57,60 65,50

20 * 88,20 * 86,80 * 66,5025 74,90 72,70 59,50

30 67,00 65,80 57,40

35 60,90 60,20 56,00

T so lieu bang 1 cho thay:

1/. Tai thi iem cc ai ham lng am amin hai lo TN eu cao hn ro retso vi lo C. So sanh gia hai loai tac nhan th hieu qua cua NaCl to ra cao hn so vi

Toluen.

2/. Ham lng am amin ca 2 lo th nghiem eu tang cao thi iem 5 gi, roiha xuong. Sau o thc s at cc ai vao luc 20 gi. Trong khi o lo C ham lngam amin at cc ai vao luc 5 gi roi giam lien tuc .

ay chung ta gap mot hien tng kha ly thu la o th t phan cua ca hai loaitac nhan eu chia lam hai vung, vi 2 gia tr cc ai (Vung I at ga tr cc ai luc 5gi, Vung II at gia tr cc ai luc 20 gi ).

Theo ly giai cua mot so chuyen gia ve lnh vc nay th tai iem cc ai th nhatcac tac nhan cha the hien tac dung, am c tch luy trong moi trng theo c chetrao oi chat t nhien. chnh v vay ch so am ca 3 lo khong co s sai khac ang ke.iem cc ai th hai mi la ket qua that s cua s kch thch t phan nh tac ong cua



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cac tac nhan. vung th 2 nay, do tac dung kch thch, cac enzim phan giai cua te baobat au hoat ong manh, mot loat cac he enzim (ma quan trong nhat la phc heProteaza A, Proteaza B, Proteaza C) c giai phong vao moi trng, chung c hoathoa va bat au phan giai cac san pham TC cua quan the te bao.

So lieu ve bien thien am Amin khi dung Nacl 5% c bieu dien tren oth 2

o th 2: Dien bien ham lng am Amin trong dch t phan bangNaCl 5%.

AM AMIN

73.05

81.6

76.2

67.9

88.2

74.9

67

60.9

50

55

60

65

70

75

80

85

90

95

100

0 5 10 15 20 25 30 35

t (gi)

Tren o th, 2 vung oc phan chia nh sau:

+ Vung 1: Dien ra t luc bat au tiep xuc vi tac nhan, ket thuc thi iem 15gi, at cc ai tai thi iem 5 gi vi lng Amin la 81,6 mg%.



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+ Vung 2: Bat au vao thi iem 16 gi sau khi tiep xuc vi tac nhan, at ccai vao luc 20 gi, v ham lng Amin la 88,2% ( trong khi lo oi chng, ham lngAmin ch con lai 66,5 mg%).

Dch sinh khoi qua t phan nay dung e thay the bot tom ( trong banh phongtom). Do vay, no chnh la nguon am cho loai thc pham cao cap nay.

IV- NG DUNG C CHE T PHAN E SAN XUAT SINH KHOI NAMMEN DI DANG BOT DINH DNG VA COM BO

1. C s ly thuyet.Te bao nam men, nh a noi tren, cha ng trong no mot lng vat chat vo

cung phong phu va quy gia oi vi con ngi. Song, do mang te bao cua chung co mot

lp vo bao ve vng chac nen neu dung dch khoi cha nhng te bao nguyen ven lam

thc an cho tre em, ngi gia, ngi benh thi se gap mot tr ngai la nhng c the nay

kho hap thu, khien cho gia tr dinh dng thc s cua che pham b giam sut ang ke.

Xuat phat t nhng hieu biet ve mot hien tng sinh hoc ac trng cua nam men

o la hien tng t phan. Ngi ta ngh en viec dung tac nhan e kch thch cho qua

trnh t phan nay dien ra sm va nhanh hn, giup cho cac thanh phan dinh dng trong

te bao c giai thoat ra moi trng. Che pham sinh khoi sau t phan se tr nen de hap

thu, phu hp vinhu cau tieu hoa cua c the, nh vay tang gia tr dinh dng cua che

pham.

Co the hnh dung c che cua s t phan nh sau:

Bnh thng, neu khong co s tac ong nao t ben ngoaith quan the te bao nam

men sinh trng va phat trien theo quy luat 4 pha:

- Pha tiem tang ( lag phase)

- Pha cap so ( logarit phase)

- Pha on nh ( EQ. phase)



16/77


- Pha t vong (Stop phase)

Khi quan the a tien en pha t vong th se xay ra hien tng t phan: Luc nay,

do chat dinh dng can kiet, trang thai te bao gia coi, cac enzym phan giai co trong noi

bao (ma quan trong nhat la he protease) hoat ong manh. Chung phan giai pha huy cacthanh phan cau truc noi bao lam v mang te bao e giai thoat cac san pham phan giai

i ra ngoai.

Nh vay hien tng t phan dien ra trong t nhien vao giai oan chot cua s

song cua quan the te bao nam men do vay luc nay nhieu san pham quy a hao hut,

chat lng cua sinh khoi kem nhieu.

Khi dung mot tac nhan ben ngoai e chu ong kch thch qua trnh t phan, giup

cho hien tngphan giai va pha v mang te bao dien ra sm hn ( vao giai oan pha

cap so), chung ta se thu c mot che pham sinh khoi cha toan nhng te bao tre, khoe,

co trang thai sinh ly toi u va co thanh phan dinh dng ay u nhat. S dung dch sinh

khoi sau t phan e lam com bo hoac bot dinh dng se tot hn nhieu so vi s dung

sinh khoi nguyen ven.

e thc hien viec chu ong kch thch qua trnht phan ngi ta a lam c 2

loai tac nhan thch hp, khong gay oc hai cho ngi dung va khong lam cho che pham

co mui kho chu o NaCl 5% va Toluen 1%

Tac dung cua NaCl la gay co nguyen sinh, pha v s can bang ap suat tham

thau khien cho cac chat trong noi bao b ay ra moi trng.Dch sinh khoi co cha NaCl

vi ty le 5%, sau o c hap thu vao cac gia the dang bot se ch e lai v man va u

am, nhp vi khau v ngi dung. Do vat ay la mot tac nhan thch hp.Touen co tac dung hoa tan thanh phan lipit trong cau truc te bao, khien cho qua

trnh tham loc cua mang b roi loan, nh the cac thanh phan cua mang b roi loan, nh

the cac thanh phan noi bao c t do thoat ra ngoai. Toluen co ac tnh la de bay hi

nhiet o cao, do vay sau khi hoan thanh chc nang t phan, co the dung bien phap un

nhe e lam bay hi het toluen ra khoi che pham.

T nhng ket qua thc nghiem thu c a cho phep chung toi rut ra mot so

ket luan co y ngha cho thc tien nh sau:



17/77


Trong quy trnh san xuat sinh khoi nam men ( e lam com bo va bot dinh

dng) th thi iem thch hp nhat e cho tac nhan t phan tiep xuc vi quan the nam

men la khoang 18 20 gi ke t khi bat au nuoi cay. Luc nay mat o te bao cung nh

lng sinh khoi tong cong at gia tr cc ai; Trang thai sinh ly te bao mc toi u,quan the te bao ang trong pha logarit.

Thi iem thch hp nhat e kch thch qua trnh t phan va tien hanh thu san

pham la vao luc 20 22 gi ke t khi cho tiep xuc vi tac nhan. Luc nay ham lng

am amin trong che pham at cc ai.

e nang cao hieu qua kinh te va ha gia thanh san pham, trong viec san xuat sinh y h


18/77


- Hap thu dch sinh khoi sau t phan vao chat phu gia.

- Gia cong che bien, say kho, ong goi.

Cong thc moi trng e nuoi cay & nhan giong nam men Moi trng Hansen: (dung trong phan lap, nhan giong, lap o th sinh

trng, th hoat tnh giong).

Glucose: 50 gam.

Pepton: 10 gam.

K2HPO4: 3 gam.

MgSO4. 7H2O: 3 gam.

Bo sung nc chiet gia au (200 gam)

Moi trng 1Glucose 50g

Pepton 10g

K2HPO4 3g

MgSO4.7 H2O 2 -5 g

Nc 1 lit

Agar 20gpH 5,6 6

Moi trng 2

Saccharose 150 g

NH4NO3 10 g

K3PO4 5 g

MgSO4 2,5 g

CaHPO4 0,5 gNc 1 lt

Agar 20 g

PH 5,6 6



19/77


Moi trng 3Saccharose 50 g

Khoai tay 300 g (got vo, un lay nc chiet)

Gia au 200 g (un lay nc chiet)Long o trng ga 1 cai/ 1 lt

Nc 1 lt

PH 5,6 6

Moi trng 4 (Moi trng san xuat)

Khoai tay 250 g (got vo, un lay nc chiet)

Ca rot 250 g (got vo, un lay nc chiet)

Gia au 250 g (got vo, un lay nc chiet)

Bot nhong tam 20 g (rang, say kho)

Dch r ng a x ly 10% (tong the tch moi trng)

Nc may 1 lt

PH 6 6,2

Nc un soi e nguoi - u 1 lt. pH 6,5 - 6,8

Ghi Chu: Neu can pha MT ac th bo sung them 20 gam Agar-agar dang bot

Moi trng 5 (MT nc chiet t nhien - dung trong san xuat com bo va botdinh dng)

Nc chiet 200 gam gia au. Nc chiet 200 gam khoai tay. Nc chiet 200 gam carot

Nc chiet 100 gam nhong tam.

Dch r ng a x ly, bo sung nc may en u 1 lt.Ghi chu: Dch r ng c x ly qua hai giai oan.

1. Lang can, loc trong bang phng phap tua loi cuon, Chat gay tua la Zelatinhoac long trang trng. Thc hien trong ieu kien 70 - 800C.



20/77


2. Loai mau: Bo sung H2SO4 am ac vi ty le 2 - 4 ml/1kg r ng (a pha

loang cho en nong o 12 - 14%) - Cho chay qua cot thuy tinh co cha hai lp Than

hoat tnh va Bong thuy tinh.

* S o san xuat com bo bang dch sinh khoi nam men qua t phan.Chung giong goc Saccharomyces

Nhan giong cac capGiong goc

Giong san xuat

Moi trng san xuat+ 28 320C+ 18 gi

Lac 150 vong/phut

+ 400C/20 gi+ Lac 150 vong/phut

Tac nhan tphan NaCl 5%

Dch sinh khoi

- Nguyen lieu hap thu- Chat ket dnh- Chat gay hng

+ Tron eu+ Ep khuon

Dch sinh khoi sau t phan

Com ti

+ Say kho+ ong goi

Com thanh pham

V - SAN XUAT SINH KHOI VI TAO

1. ac iem chung- Vong i ngan, ieu kien phat trien n gian- Sinh khoi co thanh phan hoa hoc phong phu- Nang suat quang hp cao



21/77


- Cong nghe nuoi trong de ieu khien- Thch hp vi SX cong nghiep

2.Nuoi trong Luc Tao n bao (Chlorella)

- Tao nc ngot, nguon goc on i, te bao hnh cau, mau xanh luc- S dung trong cac muc ch:

+ ieu che thc an tong hp cho ngi+ Dc pham ,

- Thch hp vi khoang nhiet o 20-25o c, pH thap- Nguon am chu yeu la Ure, nguon cac bon chu yeu la CO2- Trong san xuat sinh khoi Luc tao thng dung moi trng co cha 1% Ure , bo

sung acid acetic 1-3 g/ lt, nuoi trong nhng be xi mang co nap che ma nhng phai baoam co u nang e quang hp. Thay dch moi trng moi ngay mot lan, xuc kh lientuc.

- Thanh phan cau truc noi bao: giau protein va vitamin, co cac hoat chat dclieu quy (chong ung th, giam cholesteron, an than nhe )

Dan lieu phan tch thanh phan Axit Amin trong Luc tao nh sau:Loai A.Amin Ty le (%)

ArgininHstidinIsoluecinLeucinLyzinMethioninPhenylalaninThreoninTryptophanValin

2,29o,291,691,992,430,572,141,91o,412,61

3. Nuoi trong Tao xoan a bao (Spirulina)- Tao nc man, nguon goc nhiet i, thch hp vi khoang nhiet o 30-35o c- Nguon cac bon chu yeu la CO2 va HCO3

- S dung trong cac muc ch:+ ieu che Linavina, Lactozyl, Pirulamin( cha suy dinh dng tre em tang

lng sa cho san phu)



22/77


+ SX thc an cho au trung tom+ X ly nc thai (lam sach cac Ion kim loai nang)

Thanh phan cau truc noi bao cua Spirulina

Thanh phan Ham Lng(%chat kho)

Protein 59,94Gluxit 12,50Lipit 01,12A.Nucleic 04,29Tro 10,23

Thanh phan Ham Lng

Carotenoid 2,10 (mg/g)Chlorophyl 1,70 (mg/g)Vitamin B12 0,4-1,3 ( g/g)Vitamin A 0,3-0,6 ( g/g)



23/77


CHNG 2. NG DUNG CONG NGHE VI SINH TRONG BAOQUAN VA CHE BIEN THC PHAM

I. O NHIEM THC PHAM VA HAU QUA

1.Khai niem chung

Thc pham noi chung, ac biet la cac loai giau am, thng rat de b o nhiem.Tac nhan gay o nhiem bao gom trc het la vi khuan, sau en nam moc va nammen, khi xam nhap vao khoi nguyen lieu, thoat au chung se phat trien ve mat solng, tiep o tiet ra cac san pham thai, lam bien oi mau sac, mui v cua nguyen

lieu, dan en h hong hoac giam pham chat cua thc pham.Cac dang h hong thc pham thng gap la: hoa nhay, len men chua, lenmen thoi, len moc xanh hoac moc vang, bien sac , co mui hoi v.v

Rieng oi vi thc pham giau am th dang thng gap nhat la b thoi va oithiu do vi khuan. Cac loai vi khuan gay oi thiu chia lam hai loai:

- Loai co kha nang tiet ra nhieu enzyme hon hp, co the phan huy c tatca cac loai cao phan t protein, glucid, lipid co trong nguyen lieu.

- Loai ch co kha nang tiet ra mot hoac vai loai enzyme rieng re, do vay ch

phan huy c mot thanh phan nhat nh co trong nguyen lieu.* Hau het cac loai VSV gay o nhiem thc pham eu ong thi la tac nhangay benh cho ngi ac biet la oi vi cac benh ng ruot, (nh ta, l, tieuchay, thng han, ngo oc thc an, ay hi chng bung )

* Mot so loai Moc tiet oc to vao lng thc- thc pham, gay benh cho ngian .

V du :- Aflatoxin , gom 20 loai khac nhau (Loai B1 va M1 do Aspergilusflavus,

gay viem gan va ung th gan cho ngi, bo, cu, heo. Loai T2 do Fusarium

culmorum, gay xuat huyet, giam hong cau, teo tuy song) Nguon lay la ngu cocb moc va sa cua cac con vat nhiem benh co cha oc to.- Cac Alcaloit (Egostamin, axit secalonic do Claviceps pupurea, gay co

mach ngoai vi, hoai t TB gan, teo c va gay benh nam ca) - Ochatoxin do Alterneria, gay ung th va ngo oc thc an.



24/77


V nhng ly do tren, chong o nhiem thc pham chnh la mot khau quan trongtrong bao ve moi trng at nc khong kh va ong thi cung la mot khau coy ngha quyet nh trong cong tac bao ve sc khoe cong ong.

2. Tac nhan gay o nhiem thc pham:* Tac nhan hoa ly

- Chat bao quan- Chat phu gia- Chat nhuom mau- Kim loai nang.- Nhiet o, o am.

* Tac nhan sinh hoc

- Enzime co trong nguyen lieu.- Cac vi sinh vat xam nhap.

* Cac con ng gay o nhiem thc pham:- Suc vat b benh.- Moi trng o nhiem.- Che bien khong ung quy cach VSATTP:

+ Nguon nc dung trong che bien khong sach.+ Tay chan quan ao ngi che bien.+ Dung cu dung giet mo gia suc.+ S dung chat phu gia ba bai.

- Bao quan khong ung quy cach VSTP:+ Bao b dung cu cha ng.+ Dung hoa chat bao quan qua lieu lng cho phep.



25/77


S o: Cac con ng gay o nhiem thc pham.

SUC VAT MOI CHE Bao quan

M O nhiem nc,khong kh

-Ve sinh ca nhantay ngi lanhmang trung .

- Dung cu mat vesinh .

- ieu kien mat vesinh.

- Khong che ay- Ruoi bo

NAUKHONG KY

Nhiem vaothc pham

Ngi an

Nhiem vaothc pham

Nhiem vaothc pham

3 - Nhng benh nhiem khuan do an thc an b nhiem khuan

- Benh do Vibriocholerae: Vi khuan gay benh ta ca va cac loai thuy san covo giap ( nh tom, cua, ghe, so, oc ) anh bat t nguon nc b o nhiem. Nguyennhan o nhiem nc la do ao ho, song, rach thng la ni cha ng cac loai phanrac, nc, cong, nc thai t cac khu dan c o vao ma khong qua x ly.

-Benh do Salmonella: Vi khuan gay benh thng han. Loai vi khuan nay co

kha nang thch nghi cao va co sc chong chu tot vi cac yeu to ngoai canh. nhiet o bnh thng no co the ton tai trong phan, bui, rac ti ba thang. nhieto t 6 - 120C no co the ton tai trong thc pham 4 8 thang. Ngoai raSalmonella co kha nang chu man hn han cac vi khuan gay benh ng ruotkhac. Tht ong vat thng b nhiem Salmonella di hai hnh thc:

+ Gay nhiem ong vat song



26/77


+ Gay nhiem tht sau khi b giet va qua che bien.-Benh do Shigella: Vi khuan gay benh l trc trung. Nguon truyen benh la

cac thc an chn va cac thc an nguoi thuoc loai tht, sa. Rieng loai Shigellasonei con co the phat trien c cac loai thc uong.

- Benh do E.coli:Vi khuan gay benh tieu chay tre em va nhiem huyet tre s sinh. ay la nhom vi khuan gay benh co ieu kien ngha la bnh thngchung co the ton tai trong at, nc, khong kh, song hoai sinh, khong gay benh.Ch khi gap nhng ieu kien nhat nh va thch hp mot so loai trong chung mitr thanh gay benh.

-Benh do Proteus: Gay ngo oc thc an dang d ng. Proteus la mot dang vikhuan gay benh co ieu kien, chungthng xuyen c tru ruot ngi va ongvat di dang vo hai; khi c the suy yeu chung se lap tc phan chu va gaybenh. Neu mam benh la P. morganni th khi vao c the chung san sinh ra nhieu

chat Histamin gay noi man, nga ngay toan than o chnh la hien tng d ngdo o nhiem thc pham.- Benh do Vibrio parahaemolyticus: Vi khuan gay viem da day va viem

ruot, la vi khuan a man thng co nc bien va nc l. Nguon lay nhiem chuyeu la cac loai tom, cua, ghe, ca nhuyen the vung ven bien. Ngoai ra, cac benuoi tom nhan tao cung hay b o nhiem loai vi khuan nay.

-Ngo oc thc an do oc to gay viem ruot cua tu cau vang (Staphyloccocusaureus): Tu cau vang thng c tru trong mang ca, da va niem mac cua bo (nhat la nhng con bo b viem tuyen vu ). Cac loai thc an nhiem tu cau vang

gom: sa, cac san pham che bien t sa, cac loai banh keo co kem, ca hop va cakho phi khong ky. Tu cau vang gi nguyen kha nang gay benh trong hai thang ieu kien nhiet o thap.

- Ngo oc thc an do oc to cua vi khuan gay nhiem oc tht (Clostridiumbotulinum ): Cac vu ngo oc nay t xay ra nhng khi a xay ra th ty le t vongcao. Vi khuan nay co kha nang tao thanh nha bao ( hay bao t ) do vay sc chunhiet rat cao. oc to cua no cung oc hn so vi cac loai oc to cua vi khuankhac. Khi un soi 100oC vi thc an b nhiem Cl.botulinum van khong giet ctoan bo cac nha bao cua chung, muon bao am tuyet oi an toan can un soi lien

tuc 3 gi.



27/77


S o: C che gay nhiem va lay lan cua vi khuan

Thc pham banau

Gaynhiem

Gay onhiem

Ngi lanh mangmam benh

Ngi benh

Ngi dung

San pham o nhiem

Moi trng o nhiem (at,nc, khong kh )

(Khong hp ve sinh)Che bienBao quan

ao thai qua phan

ao thai qua phan

4.C che sinh hoa cua qua trnh gay h hong thc pham

Qua trnh h hong thc pham luon bat au be mat nguyen lieu, sau mi idan vao ben trong. Thng trong giai oan au cac vi sinh vat cha Enzyme hon

hp se nhan len trc va hoat ong manh me e khai pha nguyen lieu, sau oen lt cac cac vi sinh vat cha Enzyme n tien hanh phan huy nguyen lieu motcach manh me va triet e. Cung vi cac Enzyme do VSV tiet ra th ong thinhng Enzyme co san trong ban than khoi thc pham cung b kch hoat va thamgia vao cac phan ng phan huy, lam tang toc o h hong cua nguyen lieu.



28/77


Nguyen lieu giau ng se b len men chua, moc xanh, moc vang .Nguyen lieu giau am co c che phc tap hn, dien bien nh sau :au tien, cac vi khuan tiet Enzimproteaza ngoai bao se phan cat cac phan t

protein t nhien thanh cac chui peptit mach ngan . Tiep o, chung tiet ra cacEnzimpeptidaza phan huy chuoi peptit thanh cac acid Amin t do. Cuoi cung, cacacid amin b phan huy thanh CO2 , NH2, acid hu c, hoac cac hp chat amin . Tuyieu kien bao quan, giai oan cuoi dien ra theo mot trong hai con ng sau :

Trong ieu kien hieu kh:NH2

/R CH2 CH - COOH R CH2 CH2 COOH + NH3

Trong ieu kien k kh:

NH2/

R CH2 CH - COOH R CH2 CH2 NH2 + CO2

Thc pham khi a b bien tnh nh tren th khong the an c, amoniac gaymui hoi, cac Amin gay oc, Axt hu c nong o cao cung se gay oc. Neu b cahai nhom vi khuan hieu kh va k kh xam nhiem th mc o h hong cang nang

hn, mui hoi nang hn do s co mat cua cac san pham nh indol, skatol , phenol,H2s.

II. CAC PHNG PHAP BAO QUAN THC PHAM.

Bao quan thc pham la tm cach ngan chan, tran ap va tieu diet cac VSVgay nhiem, ong thi han che en mc toi a cac qua trnh sinh hoa dien ra trongkhoi nguyen lieu, tren c s o nham ti muc ch cuoi cung la gi nguyen trangthai va pham chat ban au cua thc pham hoac chuyen ve mot dang mi, thm

ngon hn de van chuyen hn, ma van am bao gia tr dinh dng von co cua no.Thng trong qua trnh che bien a ong thi bao ham ca cac bien phap bao quan;ngc lai, khi ap dung cac bien phap bao quan ong hi cung bao ham ca tnhchat che bien



29/77


Co the noi, ngay nay nhieu thanh tu cua nhieu lnh vc khoa hoc va kythuat khac nhau a c ap dung mot cach co hieu qua cho muc ch bao quan vache bien thc pham.

Co rat nhieu phng phap bao quan thc pham, song nhn chung cac

phng phap eu tuan thu theo mot trong 3 nguyen tac chnh sau:1- Nguyen tac Bioza (Bios = s song)

Theo nguyen tac nay thc pham c cat gi ieu kien ve sinh cao, vimoi trng vo trung tuyet oi e luon luon gi nguyen trang thai ti song banau cua nguyen lieu.

V du: e Supl, cai bap, ca chua v.v trong nha knh vo trung, co mayieu hoa nhiet o c gi 10 - 15oC .

e tht ln, tht bo ti trong phong mat, vo trung luon gi nhiet o 0o

C - 100

C.Cac phng phap nay khong thch hp vi ieu kien nhiet i, lai oi hoi thiet b

at tien, do vay Viet Nam rat t ng dung.

2 - Nguyen tac Abioza. (Abiosis = khong song)Theo nguyen tac nay ngi ta dung nhng bien phap nh ch hoan toan s song

cua vi sinh vat gay nhiem; Di tac dung cua cac yeu to diet khuan nh vay th banthan khoi nguyen lieu c bao quan cung thay oi trang thai, khong con ti song na.Thuoc nguyen tac nay co ba phng phap dc s dung:

a. Thanh trung nhiet o caoDi tac dung cua nhiet, hoac chnh cac te bao cua VSV b tieu diet; hoac cacenzym quan trong cua chung b bat hoat, do vay khong gay nhiem c. Phng phapnay con c goi la S dung qua trnh nhiet nong. Tuy loai thc pham ngi ta co thethc hien viec kh trung nguyen lieu ba khoang nhiet o khac nhau. Keo dai trongnhng khoang thi gian nhat nh.

V du: - Vi loai thc pham co nhieu ng bot, de b chay can duy tr 80 900C, trong 30 45 phut.

- Vi nhng nguyen lieu dang am duy tr 90 1000C trong 45 60 phut.- Vi nhng dang o hop hoac vo giap cng co the duy tr 110 150

0

C vaap suat t 1,2 1,5 at v.vb. Chieu xa va sieu am

Cac tia hong ngoai, t ngoai; Cac tia bc xa dang , , , X, vv gay oxyhoa hoac ion hoa, do o tao ra mot trong nhng hieu qua sau oi vi VSV gaynhiem:

- Thay oi thanh phan cau truc te baoThS. Bach Phng Lan Khoa Sinh hoc


30/77


- Pha v mang- Bat hoat he Enzyme- Song sieu am vi tan so tren 20.000 Hz pha v mang te bao.Han che cua phng phap nay la gia thanh rat cao va oi khi khong an toan

cho ngi thc hien cung nh ngi tieu dung, do vay t c s dung.c.Dung cac hoa chat bao quanNhieu loai hp chat vo c cung nh hu c co tac dung sat trung. C che

tac dung cua no the hien qua nhieu phng thc khac nhau:- Pha huy thanh phan cau truc te bao- Ngan nga s sinh tong hp Enzyme va cac Protein cau truc khac (theo c

che cam ng hoac c che)- Gay roi loan qua trnh tham thau qua mang te baoCac loai hoa chat thng dung gom:

* Cac hp chat sulfit va bisulfit nh K2SO3, Na2SO3, NaHSO3, KHSO3,Ca(HSO3)2 Cac chat nay thng dung vi nong o di 3%. Tac dung cua no cche qua trnh sinh tong hp cac protein co cha S (theo c che cam ng)

* Cac hp chat Benzoat va cac hp chat Oxy hoa kh- Axit benzoic C6H5COOH thng dung vi nong o di 0,2 %- Benzoat Natri C6H5COONa thng dung vi nong o di 0,2 %- Borat Natri (Han the) Na2B4O7 thng dung vi nong o di 0,1 %- Nitrat Kali KNO3thng dung vi nong o di 0,1 %

Tat ca cac hp chat tren eu gay tac dung c che s trao oi chat mot

khau nao o. Rieng benzoat Natri co tac dung ro ret nhat oi vi nam moc, no cche chu trnh Ure cua te bao.ieu can lu y la nhng hp chat tren eu gay oc hai cho ngi dung, do

vay khong c dung qua lieu quy nh.Trong so cac hp chat tren, co mot loai ma oc tnh cua no rat ang ngai,

nhng c dung mot cach rong rai va tuy tien trong lnh vc thc pham o lahan the (Borat Natri). Do han the va co tac dung chong moc, chong chua, lai vaco tac dung tang o deo cua cac nguyen lieu dang bot nen ngi ta dung no khisan xuat m an lien, banh a, banh deo, com bo v.v ieu nay can khuyen cao e

nhng ngi san xuat thu cong t nhan co y thc ung an khi s dung hp chatnay.* Ngoai cac hp chat noi tren, oi khi ngi ta con s dung vai loai khang

sinh co hoat tnh khang khuan manh nh Tyrozin, Biomycine v.v nhng chat nayco tac dung tot vi vi khuan nhng t hieu qua oi vi nam moc.



31/77


3. Nguyen tac Anabioza (= giam s song)(Anabiosis = dang song ngam = song tiem sinh)

Theo nguyen tac nay ngi ta ap dung nhng bien phap nham han che sphat trien cua VSV va han che cac hoat tnh cua cac Enzyme nhng khong giet

chet hoac nh ch hoan toan.Thuoc nguyen tac nay co 5 bien phap chnh thng c s dunga.ng dung qua trnh nhiet lanhPhng phap nay con c goi la Lu gi thc pham trang thai lanh hay

ong lanh.- Thc pham c gi nhng nha lanh nhiet o O0C se bao quan trong

vai thang.Thc pham c gi trang thai ong lanh tc la nhng can phong ma

nhiet o c giam t t cho en khi at ti 10 0C en - 200C (nhiet o thap hn

nhiet o ong bang cua nc a ) nhiet o nay co the bao quan t 6 thang envai nam. nhiet o thap s sinh trng va phat trien cua VSV tam ngng, hoat

ong cua cac Enzyme b nh ch, cac qua trnh sinh hoa trong thc pham b cche; nhng neu em khoi nguyen lieu tr ve nhiet o thng th moi hoat ong cothe c hoi phuc, bi le VSV khong b giet chet (nhat la nam moc), no ch gi trang thai tiem sinh ma thoi. Do vay thc pham ong lanh khi a lay ra khoi nibao quan can c s dung sm, trc khi khoi nguyen lieu tan gia.

b.Bao quan thc pham bang cach phi hay say kho.Phan ln vi khuan ch sinh trng va phat trien c trong ieu kien toi thieu

la 30%; nam moc th oi hoi moi trng co o am toi thieu la 15%. Khi em phihay say kho thc pham, tc la lam cho o am cua nguyen lieu nho hn o am toithieu, khien cho cac VSV gay nhiem khong the phat trien c. Neu say hoacphi khong ky, hoac sau khi phi, say bao goi khong tot e nguyen lieu b am trlai th thc pham se b h hong.

Bien phap nay thng c ap dung oi vi cac loai hai san va nam an.c. Bao quan thc pham bang cach tao ap suat tham thau cao.

Khi moi trng ben ngoai co ap suat tham thau cao hn ben trong te bao

VSV se xay ra hien tng co nguyen sinh co ngha la nc trong te bao VSV brut ra ngoai, nguyen sinh chat b ong ac roi tach khoi mang te bao dan dan chet.

e tao ap suat tham thau cao cho moi trng can chu y chon nhng tacnhan khong gay oc, bi v phai s dung mot nong o kha cao mi u ngng baoquan. Thng thng ngi ta dung muoi an (NaCl) va ng knh (Saccharose).



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Muoi an NaCl co tnh chat sat trung nhe, han che s hoa tan Oxy vao moitrng, do vay km ham hoat ong cua bon VSV hieu kh. Rieng ion Cl- con cokha nang c che Enzyme Protease.

Khi dung muoi an e bao quan thc pham tc la cung mot luc tan dung

nhng hieu qua sau:+ c che s phat trien cua VSV do cac tinh chat noi tren cua NaCl.+ Tao ra ap suat tham thau cao e gay co nguyen sinh.+ Lam giam o am cua khoi nguyen lieu.Ngi ta thng ap dung bien phap muoi muoi man e cat gi tht muoi va

nam muoi. Dung ng Saccharose cung co tac dung tng t nh muoi an. Khi dung

ng e lam cac loai mt tc la cung mot luc ng dung 3 qua trnh:- Gay co nguyen sinh oi vi cac VSV a nhiem trong nguyen lieu e tieu

diet chung- Lam kho nguyen lieu e khien cho cac VSV mi khong u o am e xam

nhap va phat trien- Dung nhiet o cao (khi nau mt) e sat trung - Cac loai mt sau khi lam xong neu c bao goi tot co the bao quan lau. d. Bao quan thc pham bang acid.

a so cac loai VSV gay nhiem cho thc pham eu hoat ong tot khoang pH tren 4,5 , khi pH ha xuong di ngng nay chung ngng phat trien.Ngam thc pham vao acid tc la tao ra xung quanh khoi nguyen lieu mot moi

trng co pH thap di 4,5.Loai acid thng dung nhat la acid acetic CH3COOH. nong o t 6 10% acid nay c goi la giam an. oi khi ngi ta dung acid Citric hay con goi laacid Limonic, tc la loai acid co nhieu trong qua chanh.

Bien phap nay c dung e ngam chua cac loai cu, qua an thay rau (nhda chuot, su hao, cu cai, nam m v.v).

Rieng oi vi cac dang nguyen lieu co ham lng Celluloza cao ngi tacon dung hai loai acid khac la: acid tractic va acid lactic.

Cong thc hoa hoc cua cac loai acid tren nh sau:

+ CH3COOH Acid acetic+ CH3-CHOH-COOH : Acid lactic+ CH2COOH

HO-COOH Acid citricCH2-COOH

e. Bao quan thc pham bang kh tr va kh Cacbonic



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Mot trong nhng nguyen nhan gay h hong thc pham la do tac dung cuaoxy co trong khong kh: phan t O2 khi tiep xuc vi nguyen lieu se tham gia vaocac phan ng Oxy hoa kh lam cho mot so thanh phan co trong nguyen lieu bphan giai va bien tnh. e khac phuc tnh trang nay ngi ta tm cac bien phap

ngan cach khoi nguyen lieu vi khong kh, bang cach dung mot khoi lng kh trN2 c hoa long -1270C. Cung co the dung mot bien phap th hai la ieu chnhty le cua bau khong kh trong kho cha thc pham bang cach giam thap lng 02va tang lng CO2.

Khi ha ty le O2/CO2 a cung luc tao ra hai hieu qua.- Tranh hien tng phan huy nguyen lieu.- c che s sinh trng va phat trien cua bon VSV hieu kh.

f.Bao quan thc pham bang cach tao ieu kien cho mot qua trnh len men co li

Len men la qua trnh chuyen hoa cac nguyen lieu dang glucid thanh ruva acid hu c nh hoat onh cua mot so VSV ac chung. Neu san pham ruhoac acid hu c hnh thanh la nhng chat khong oc va co hng v thm, ngonhp vi s thch cua con ngi th chung c goi la nhng qua trnh len men coli

Tao ieu kien cho mot qua trnh len men co li von la mot phng phapco ien va thng c ng dung rong rai trong viec che bien va bao quan cacloai rau qua, nam an, tht ln v.v

Nguyen lieu sau khi trai qua qua trnh len men se tr nen co kha nang tbao quan ngha la se lu gi c lau ma khong b h hong; ong thi chungcung tr thanh nhng mon an co hng v thm, ngon rat ac trng.

Neu biet tao ra nhng ieu kien toi u cho mot qua trnh len men co lidien ra hoan hao th cung mot luc chung ta at ti nhng hieu qua sau:

- Cac VSV gay len men se phat trien manh, gay ap ao ve so lng khiencho cac VSV gay oi thoi b kiem ham, khong phat trien c trong khoi nguyenlieu.

- Cac san pham len men tiet vao moi trng se chuyen nguyen lieu vetrang thai chn sinh hoc, tao ra hng v thm ngon, ong thi gop phan c che sxam nhap cua cac VSV co hai.

- Tao ra o pH thap, khong thch hp vi bon VSV gay oi thoiBien phap nay n gian, re tien v khong ton nhien lieu e say, khong can

en cac hoa chat at tien va ac biet la khong gay hai oi vi ngi tieu dung, do



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vay ang c ap dung rong rai e bao quan rau, qua, nam an, tht ong vat.Nhng qua trnh len men co li thng dc dung la Len men Lactic, Len menEtilic, Len men Acetic (xem chng 3)

III. S DUNG NHOM NAM MOC TRONG BAO QUAN VA CHE BIENTHC PHAM

Dung bien phap vi sinh e bao quan va che bien thc pham tc la s dungmot noi vi sinh vat nao o, co kha nang phan giai nguyen lieu, nhng chung khonglam hong nguyen lieu, ma trai lai, chung chuyen hoa nguyen lieu sang mot dang

san pham khac: thm, ngon hap dan hn.Ba nhom VSV thng c dung nhieu trong lnh vc nay la nhom nam moc

phan giai protein, nhom vi khuan len men Lactic va nhom nam men.

Trong chng nay ch e cap en viec s dung nhom nam moc, hai nhomcon lai dc trnh bay trong cac chng khac (Xem chng1 va chng3)

1. C s sinh hoc cua viec s dung nam moc trong che bien

va bao quan thc pham.

Nam moc thng dung cho muc ch che bien cac loai nc cham va mon angiau am co nguon t thc vat, bao gom: x dau, magi, tau v yeu, tng, chao

Nguyen lieu khi au cua cac mon an tren la au tng, au nanh, au phu,kho dau lac (hay con goi la kho dau au phong). Rieng oi vi cac loai tng thcan en mot nguyen lieu th hai la gao nep.

Cac loai nc cham thc vat khi c ieu che theo phng phap Vi sinh vat(nh tac dung cua nam moc) c goi chung la "cac loai nc cham len men"

oi vi tat ca moi ngi dan, nc cham thc vat la thc an quen thuoc, gopphan lam tang nguon dinh dng am cho ba an, co tac dung nh nhng gia v

ngon mieng va kch thch tieu hoa. Rieng oi vi nhng ngi ma v benh tat hoacv co thoi quen an chay ma phai kieng thc an ong vat th cac loai thc phamtren tr thanh nguon cung cap am chu yeu cho moi ba an cua ho.

e che bien cac loai nc cham len men co the dung phng phap len ment nhien theo dan gian - tc la s dung chnh nhng nam moc du nhap t khongkh vao nguyen lieu mot cach tuy tien. Lam nh vay co mot nhc iem rat ang



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ngai la khong the kiem soat c s gay nhiem, trong o co ca nhng loai phatsinh oc to. Bi vay, cach tot nhat la nen s dung cac giong thuan a c kiemtra ky ve hoat tnh phan giai nguyen lieu cung nh c am bao rang chungkhong gay oc.

Tat ca cac giong moc c a vao san xuat nc cham len men can phai atc ay u cac ieu kien sau ay:1)Giong thuan khiet.2)Co kha nang sinh Enzyme Protease vi hoat lc cao.3)Co sc phat trien manh, co kha nang lan at cac tap khuan khac.4)Khong sinh oc to Aflatoxin, Ochatoxin 5)Tao hng thm cho san phamieu kien moi trng thch hp nhat cho s sinh trng va phat trien cua cac

giong moc phan giai Protein la

- o am 45- 50%- Nhiet o 27 - 30oC- Thi gian 60 - 72 gi.Tuy tng loai nguyen lieu can che bien ma ngi ta s dung cac chung giong

moc khac nhau; song nhn chung, qua trnh phat trien cua moc trong nguyen lieudien ra theo cac giai oan sau:

Giai oan 1 (sinh trng): sau khi cay giong vao nguyen lieu t 8 - 10 gimoc bat au phat trien , phan chia va hoat ong ho hap lam cho nhiet o trongkhoi nguyen lieu tang dan, nhng khoi lng khuan ty luc nay van con t

Giai oan 2 (len meo: si moc (Khuan ty) phat trien manh, toa nhiet nhieuhn lam khoi nguyen lieu nong len, si moc co mau trang, ket thanh tng tang vaphu khap mat khoi nguyen lieu.

Giai oan 3 (phan giai): Sau 24 gi bao t moc hnh thanh nhieu va comau vang nhat hoac hong nhat (tuy loai giong). ong thi luc nay nam moc mibat au tiet vao moi trng cac loai enzyme ac trng, ma quan trong nhat la cacProtease, cac enzyme nay hoat ong phan giainguyen lieu, phan huy cac machpeptit cua cac phan t protein, giai phong ra cac acid amin t do. Chnh v vay ma

gia tr dinh dng cua nguyen lieu tang len, ong thi nguyen lieu co mui thmac trng. Luc nay nguyen lieu a at trang thai chn sinh hoc. Cong viec tieptheo ch con la chiet rut lay san pham (neu can) roi lu gi va bao quan.

2.. San xuat nc cham len men t kho dau lac

Mot trong nhng loai nc thong dung nhat la x dau. Chung nam mocthng dung trong san xuat x dau laAspergillus oryzae vaAspergillus flavus. Cac



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nha nghien cu a khang nh rang, cac chung Asp noi tren, neu cay truyen nhieulan tren moi trng tong hp se mat hoan toan kha nang sinh oc to Aflatoxin.Mac du vay, e chac chan khi san xuat nen kiem tra lai oc tnh cua cac chunggiong tai cac trung tam bao tang giong ang tin cay.

Cac chung giong Aspergillus dung trong san xuat nc cham thng taora 3 loai enzyme quan trong:

- He enzyme protease

- He enzyme Amilase

- He enzyme oxy hoa kh

Qua trnh phan giai nguyen lieu di tac dung cua cac enzyme tren dien ra nh sau:

* Hoat ong cua he Protease:

au tien la hoat ong cua Enzyme Protease exopeptidase, pH thch hpcho hoat ong cua chung la 6,5, lng Protease exopeptidase at cc ai saukhoang 36 42 gi ke t khi cay giong vao nguyen lieu. Luc nay Enopeptdasebat au hoat ong manh, chung tac dung vao cac cau peptide mach ngan tronglong phan t, ong thi cac Exopeptidase tiep tuc phan giai e giai phong ra cacacid amin n phan t. Hoat ong cua he protease cang manh th s phan giainguyen lieu cang triet e va ham lng am amin trong nuyen lieu cang cao, ieuo co ngha la gia tr dinh dng cua san pham cang ln va v ngot cang am a.Moi loai acid amin co mat trong nc cham eu gop phan tao nen v ngot ac

trng cua san pham. V du:- Glutamic tang v ngot cua am.- Methionin va Cystein tao v thm cua x dau- Lyzin, Alanin, prolin, Leucin.v.v gop phan tao nen mot v am a giup

an ngon mieng. Hoat ong cua He enzyme proteaza ong vai tro hang au trongqua trnh phan giai nguyen lieu va no la yeu to quyet nh chu yeu oi vi chatlng san pham.

* Hoat ong cua he AmylaseHe enzyme Amylase cua Aspergillus gom hai thanh phan alpha Amylase va

glucose Amylase. Khoang pH toi u cua chung la 4,7 4,9. Alpha Amylasethuy phan thanh phan glucid trong nguyen lieu tanh maltose va dextrin. Tiep oGlucose Amylase phan cat hai thanh tren thanh glucose. Chnh v vay x dau co vngot cua ng.



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*. Hoat ong cua he oxy hoa kh.

He ezyme nay cung gom 3 thanh chnh. Hoat ong cua no co tac dung taomau va gop phan ngan can s gay nhiem cua cac tap khuan. Cu the:

- Ezyme peroxydase: oxy hoa cac acid amin dang L, nh vay tao mau o nau chonc cham.

- Glucose oxydase: ngan nga s bien oi trang thai mau sac cua sanpham, no xuc tac cho phan ng chuyen hoa glucose thanh gluconic va H2O2.

- Catalase: xuc tac cho phan ng kh H2O2 tao nc va oxy. Toan bo cacphan ng tren lap thanh mot he thong kn, chuyen hoa lien tuc, tao nen mot hieuqua khang khuan, ngha la no giup cho nc cham len men giam ty le nhiem banbi cac VSV khac.

S o phan ng nh sauGlucoseoxydase

C6H12O6 + O2 + H2O C6H12O7 + H2O2

Glucose Catalase Gluconic

H2O2 H2O + O2

Trong cong nghiep san xuat nc cham, sau khi nguyen lieu a chn sinhhoc nh hoat ong phan giai cua cac phc he Ezyme cua nam moc th can thuyphan nguyen lieu bang nhiet, vi s co mat cua mot lng nho acid HCl. Muc chcua giai oan nay la nham phan giai triet e phan Protein con lai trong nguyenlieu ma nam moc cha the thc hien c, ong thi nham hoa tan cac thanh phancan thu nhan vao dung dch, tach ri chung khoi can ba nguyen lieu.

Tiep theo cong oan thuy phan la cong oan chiet tach nham thu nhandch nc cham va cuoi cung x ly loai vang, ieu chnh pH, thanh trung nhe roiong chai. Quy trnh ieu che nc cham t nguyen lieu banh kho dau lac theophng phap len men nh nam moc gom cac cong oan sau:

1)X ly banh kho dau2)Cay giong moc, u len meo3)Phan giai Protein4)Thuy phan nguyen lieu bang nhiet (co bo sung HCl vi mot ty le nho)5)On nh, trung hoa ong chai* Cong thc phoi che nguyen lieu:



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Banh kho dau 10 kg

au nanh rang 1 1,5 kg

HCl 200 be 1 1,5 kg

Mui v x dau 0,5 1 kgChat phu lieu Tuy y

Nc u 100 lt



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S o san xuat nc cham len men

Banh kho dau (10 -12 kg)

- Xay nho, ngam nc voi- Hap chn, anh ti- Vat loai nc- Vat x ly

Bot kho dau chn

Giai oan u lenmen 5 7 ngay

Giong sanxuat

Nhan giongcac cap

Gionggoc

Giai oan phangiai protein12 30 ngay

Cay giong trai rakhay, tron eu, themnc va gi am lientuc- e 27 280C

+au nanh rang+ Muoi NaCl+ Nc: 30 lt+ Khuay tron+ Phi nang

+ NaCO3 hoac C6H5COONa+ Nc 60lt

+ ng knh 20 g/l+ Loc, kh trung+ ong chai

Nc cham ban thanh pham (40

+ HCl (1 1,5 lt)+ Chat phu gia+ Bot chnh mau + v+ un tren bep cach cat hoaccach nhot (135 1500)

Hon hp nc cham tho(40 lt)

Kho dau mocKho dau len men

Nc cham thanh pham

Giai oan trung

hoa on nh



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3. San xuat chao t au phuLoai nguyen lieu dung trong san xuat chao la au phu (hay con goi la au

khuon, au hu) Loai nam moc chuyen hoa nguyen lieu trong chao thuoc giong

Mucor, gom cac chung :M.himalis, M.silvaticus, M.subtis, M.rouxit.

He khuan ty cua Mucor trong chao co mau trang hoac nga nga vang. Si

phat trien phan nhanh chang cht, tao thanh mot lp mang hi nhay, phu kn be

mat nguyen lieu.

He Enzyme cua moc chao bao gom :Protease, Glucoamilase ,

Phospholipase. Di tac dung cua Phospholipase cac Phospholipit, ma quan trong

nhat la leucitin, se c phan giaithanh cac axit beo nh Palmatic, limoleic.; tao

v beo ac rng cho san pham.

e che bien chao co the cay giong thuan hoac e len meo t nhien theo dan

gian. Quy trnh gom cac giai oan chnh nh sau :

(1) x ly nguyen lieu (cat mieng, ngam trong dung dch muoi an 6% +

A.citric 2,5%, u 90oC trong 15 phut, vt ra e

kho)

cay giong moc

(2) u meo- 30 o C / 3 ngay

- ay vai man

(3) au len Meophan giai NaCl 100g

Nc chn 800ml

30 -32 o C / 3 ngay

(4) Chao thoon nh NaCl 100g-200g

con thc pham 50-70ml

30 -32 o C / 3- 5 ngay

chao thanh pham ong goi



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Cong thc moi trng dung e nuoi cay va nhan giong nam moc.1.Moi trng Sabauraul

Pepton (hoac lactamin) 10g

Maltose (hoac glucose) 40 gNc 1 lt

PH 5,6 6,0

2. Moi trng Hansen

Glucose 50 g

Pepton (hoac lactamin) 10g

K2HPO4 3 gMgSO4.7H2O 2 5 g

Nc 1 lt

PH 5,6 58

3) Moi trng Czapek

NaNO3 2 3 g

K2HPO4 1 1,5 g

MgSO4 0,5 g

KCl 0,5 g

FeSO4 0,1 g

ng knh 30 g

Nc 1 lt



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IV. KIEM NGHIEM THC PHAM

Muc ch cua viec kiem nghiem thc pham la e anh gia chat lng san

pham theo tieu chuan quy nh chung cua quoc gia. Co 3 nhom ch tieu can kiemnghiem nh sau :

1.Nhom ch tieu cam quan- Mau sac, mui v- Trang thai cau truc

2.Nhom ch tieu hoa ly- Ham lng am tong so ( thng xac nh bang phng phap

Microkjelhdal)- Ham lng ng kh

- Ham lng axit

- o con

- Ham lng aflatoxin (neu can)

3.Nhom ch tieu Vi Sinh- Tong so vi khuan hieu kh (TSVKHK)- Coliform (ch so coly)- Clostridium perfrigenes- Staphylococcus aureus- Bacillus cereus- Cac Vi khuan gay benh ng ruot (ta, l, thng han)

* oi vi moi nhom ch tieu se co nhng tieu chuan dnh lng cu the cho

tng loai thc pham rieng biet

4- Y ngha cua cac ch tieu vi sinh* Tong so vi khuan hieu kh

- Ch tieu nay cho biet s bo ve mc o o nhiem chung cua mau thc pham.



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- Tong so vi khuan hieu kh la tong so cac loai vi khuan a kh (ieu kien co oxit do) co trong mau thc pham hoac mau nc.

- S dung ky thuat em khuan lac tren thach a.* Coliforms

Ch tieu nay phan anh tnh trang o nhiem phan cua thc pham do dungnc khong sach hoac do ni giet mo khong ung quy cach.

Co hai mc o Coliforms can phan biet Coliforms tong cong la nhng trc khuan ng ruot gram (-), hieu kh

hoac k kh tuy tien, khong co nha bao, co kha nang len men ng lactose sinhhi, sinh acid nhiet o 350C 370C/24-48 gi. Nhng vi khuan nay co the tontai trong ruot ngi, suc vat va ca ngoai canh gom cac loai sau:

- Escherichia coli

- Klebsiella- Enterobacter- Citrobacter

Coliforms phan ( Faecal Coliforms ) la nhng coliform co nguon goc t phanngi va ong vat mau nong, cung phat trien c trong moi trng lactose comuoi mat va ch th mau nhiet o 44,5 0,50C/ 24-48 gi. Co kha nang thuyphan tryptophan trong moi trng sinh indol, khong sinh aceton, khong s dungcitrate lam nguon Cacbon duy nhat.

*Staphylococcus aureus

Staphylococcus aureus la cau khuan gram (+),sap xep hnh chum nhohoac ng thanh tng cap va chuoi ngan. Staphylococcus aureus thng b tonthng khi x ly bang nhiet va cac chat tay ra ve sinh. Do o s hien dien cuavi khuan va oc to cua chung trong thc pham a che bien hoac tren cac thietb che bien thc pham la dau hieu cho biet ieu kien ve sinh trong qua trnhche bien khong at.

*Clostridium perfringensClostridium perfringens la vi khuan ch iem s o nhiem do phan ngi,

ong vat, bun at, nc cong ranh mc o nghiem trong. Vi khuan co nha baova co sc e khang cao. Neu thc pham che bien khong am bao ve sinh, nhieto kh khuan, un nau khong u e diet nha bao, vi khuan van con ton tai vaphat trien, lam h hong thc pham va gay ngo oc thc an ( nhat la thc pham ohop ).

*Bacillus cereus



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- Xac nhBacillus cereus e anh gia s o nhiem moi trng xung quanh trongqua trnh che bien thc pham. Vi khuan nay hien dien trong at bui, cac loai thcpham (sa, tht, rau qua, hon hp gia v va ac biet trong cac thc pham bot).- Bacillus cereus la nhng trc khuan gram (+) hieu kh, va k kh tuy y, di ong,

tao noi bao t, len men glucose, sinh hi, phan ng Voges Proskauer (VP): (+),co kha nang s dung nitrate. Loai nay tang trng c trong khoang nhiet o t5 500C, toi u 35 400C; pH dao ong t 4,5 9,3; de tao bao t, bao t naymam rat de dang.

*Salmonella- Salmonella la trc khuan thng han , gram am, hieu kh va k kh tuy y, co khanang di ong, khong tao bao t, len men glucose va manitol sinh acid nhngkhong len men saccharose & lactose, khong sinh indol, khong phan giai ure,khong co kha nang tach nhom amin t tryptophan, hau het cac chung eu sinh

H2S. Cho en nay a xac nh c 2339 serotype ( kieu huyet thanh ) thuocgiong Salmonella .

* Vibrio parahaemolyticus- Vibrio la vi khuan ta, gram(-), hnh que hai au khong eu nhau tao thanh hnhdau phay, di ong, song k kh tuy y, co phan ng catalase va oxidase(+), lenmen glucose nhng khong sinh hi, khong tang trng trong moi trng khong comuoi. Co kha nang kh nitrat thanh nitrit.

- Vibrio parahaemolyticus phat trien tot trong moi trng co nong o muoi en8% nhng b c che moi trng co nong o muoi 10%.



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CHNG 3. CONG NGHE LEN MEN

Cong nghe len men la lnh vc san xuat cac loai ru va axit hu c bang con

ng len men nh cac vi sinh vat. Can phan biet hai phng thc len men :

Len men k kh ien hnh :C chat c phan giai qua mot loat cac phan ng Oyhoa kh, trong ieu

kien khong co s tham gia cua Oxy khong kh ma ch co s cho - nhan Hydro.Trong qua trnh len men , H+ thoat ra giai oan ng phan khong dcNADH2 chuyen en chuoi ho hap te bao ma c gan vi cac chat trao oichung gian cua chnh chuoi chuyen hoa e tao san pham cuoi, ong thi giaiphong cac NAD+.

San pham cua Cac qua trnh len men k khthng gap trong san xuat la :

Ten san pham Cong thc hoa hoc

1. Ru Etilic2. Axit lactic3. Axit suinic4. Axit butiric5. Axeton6. Glixerin7. Ru Butilic8. Axit Formic9. Kh Metan

CH3 CH2 OHCH3 - CHOH COOHHCOOC - CH2 - CH2 COOHCH3 CH2 CH2 COOHCH3 CO CH3

CH2OH - CHOH CH2OHCH3 - CH2 CH2 CH2 OHH COOHCH4

Len men hieu kh:C chat dc phan giai trong ieu kien co Oxy phan t tham gia, nhng

qua trnh Oxy hoa dien ra khong triet e en cung e tao CO2 va H2O ma dng

lai san pham trung gian la Ru hoac Axit hu c v vay con c goi la cacqua trnh Oxy hoa khong hoan toan .

San pham thng gap trong cac qua trnh len men hieu kh la:- Axit axetic CH3 COOH- Axit Xitric CH3 OH CH2



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COOH COOH COOHTrong chng nay ch e cap en 3 qua trnh len men tieu bieu, thng

c goi la Qua trnh len men co li trong bao quan va che bien thc pham,bao gom len men Etilic (1), len men Lactic(2), len men Axetic (10).

I. . LEN MEN ETILIC VA NG DUNG.

1. C che ly thuyet cua qua trnh len men Etilic

Len men Etilic la qua trnh chuyen hoa dng thanh ru, dien ra trong ieukien k kh. Co nhieu loai VSV co kha nang len men ru, song nhom co hoattnh cao nhat la nam men thoc cac loai sau:

- Saccharomyces cerevisiae (te bao hnh ellip)- Saccharomyces carlbergensis (con goi la Sac.uvarum , te bao hnh ellip)- Saccharomyces vini (te bao hnh ellip)- Shizo Saccharomyces (te bao hnh que)- Kluyveromyces (te bao hnh que)Tat ca cac chung nam men len men ru eu co chung cac ac iem sau:

(a) Co kha nang tong hp hai loai En zim ac hieu cho phan ng chuyen hoaA.Pyruvic thanh ru Etilic o laPyruvatdecarboxylasevaAlcoholdehydrogenase

(b) - Sinh trng hieu kh, nhng khi len men Etilic th lai thc hien trongieu kien k kh ; o vay trong quy trnh cong nghe luon can phan bet hai pha pha au la len men hieu kh e tang mat o te bao, pha sau la len men k kh etao ru.

(c) - v co ac iem (b) noi tren nen neu trong qua trnh san xuat ( pha thhai) neu e cho khong kh lot vao se xay ra hien tngHieu ng Pasteur hydrob tranh chap a vao ho hap hieu kh tao ATP - ong thi ru se b chua , do covi khuan Axetic lot vao va chuyen ru thanh dam

(d) Nguyen lieu dung trong san xuat co the la ngu coc hoac dch r ng,trai qua qua trnh phan giai trung gian thanh ng Glucose, sau o ng clen men tao Etylic. Qua trnh len men ru thc s c tnh t C chat ban aula ng Glucose, dien ra theo cac bc:



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- Glucose c phan giai theo chu trnh EMP tao Axit Pyrucvic, giai phongH+- Loai CO2 tao Andehyt, do s xuc tac cua Pyruvatdecarboxylase

- Gan H+ tao Etilic do s xuc tac cuaAlcoholdehydrogenase

*S o tong quat cua qua trnh len men ru Etilic:

2CH3-CO-COOH CO2

NADH Pyruvatdecarboxylaza

2CH3-CHO

NAD+ 2H+

Alcoholdehydrogenaza

C6H12O6

CH3 CH2 - OH

2 - Phan biet cac dang san pham len men ru

- Ru qua chng cat ( ru trang, con thc pham, con cong nghiep )- Ru khong qua chng cat( ru nep, ru can .)- Vang qua ( vang nho, vang dau , champagne .. )- Bia ai mach ( bia hi, bia chai ..)- Nc giai khat len men ( nc Kvat, bia trai cay )

3 Quy trnh san xuat bia ai mach

a/ Nguyen lieu :- Bot malt ai mach: hat ai mach nay mam, xat vo, xay nho, thuy phan

qua nhieu lan gia nhiet e thu dch nha a dng hoa . Trong dch nhaco cha Glucose, Maltose va mot ty le nho dextran, amilose.



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- Tinh dau Hublon: chiet rut t hoa cai cua cay Hublon, trong o co chacac loai tinh dau ang va tinh dau thm (Gunulon, Lupulon, Tanin). Cothe dung hoa ti roi un lay nc chiet, hoac dung cao a che bien san.

- Nc : Nc dung e san xuat bia phai at cac tieu tieu chuan hoa ly vavi sinh nghiem ngat nh sau :

- Nc mem ( o cng tam thi = 0,7, o cng vnh cu = 0,4 - 0,7

-Ham lng can chat kho khong qua 600mg/lit- Ham lng sat khong qua 0,3 mg/lit-Khong co hoac rat t cac hp chat Nitrat & Nitrit-Tong so vi khuan hieu kh (TSVKHK) khong qua 100 TB/ml-Coliorm khong qua 3 TB/ ml-Hoan toan khong co vi khuan gay benh ng ruot (VKGBR)

b. S o Quy trnh san xuat bia

Dch nha 12- 14% Cay giong

Len men hieu kh 6-10 ngay, 15-28 o c

PH 6,5 6,8 / nong o Oxy =6mg /lit

Dch len men

Len men k kh 6-10 ngay, 1- 3

o

cNong o CO2 = 0,3%Bia non

Lam lanh 0 o c, 12- 14 gi, Lang can, lam trong

Bia ti San pham bia hi (s dung trong 24 gi)

U 60 - 70 o c

ong chai lan I U, Loai can, ong chai lan II

San pham bia chai (bia on nh)



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4 - Quy trnh san xuat vang nho

a. Phoi che nguyen lieu ( e san xuat 200/lit vang)

- Trai nho chn : 10 Kg ( ra sach, ngam nc muoi, e kho, ep rap)- ng saccharose : 1- 2 kg- Con thc pham 96 o : 2- 3 litb.S o quy trnh san xuat vang

Hon dch trai cay cay giong

Them ng, len men hieu kh, 18-20 o c, 4-5 ngay

Dch len men (1-2 o con)

Loai xac, them con (0,5 1 lt)

Len men k kh, 15 18 o c , 6 7 ngay

Vang tho (8 12 o con)Them con (0,5 1 lt), them nc cho en 100 lit

Len men k kh , 10 - 12 o c, 28 30 ngay

Vang tho (12 16 o con)

Lang loc, loai can ong chai lan IVang trong , ban thanh pham

Len men k ph, 10 12 o c, 28 30 ngay

Loai can, ong chai lan II

Vang thanh pham (14 18 o con)

U lanh ( ha tho ), 5 -10 o c

Vang on nh ( co the e nhieu nam)



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II . LEN MEN LACTIC VA NG DUNG.

1. C che ly thuyet cua qua trnh len men LacticDung nhom vi khuan len men lactic cho muc ch bao quan va che bien thc

pham chnh la a s dung bien phap tao ieu kien cho mot qua trnh len men coli, ma trong trng hp nay la qua trnh len men Lactic.

T thi xa xa , khi trnh o van hoa - khoa hoc cua xa hoi loai ngi con hetsc s khai th ngi ta a biet muoi chua cac loai da, ca, cai cu, cai bap, suhao.va lam sa chua, men chua, e tao mon an cho gia nh

Khi che bien cac mon an tren ngi a ta ap dung c che len men lactic dovay, ay von la mot bien phap bao quan thc pham co ien va quen thuoc. Cac vikhuan len men lactic co nhieu trong khong kh, chung thng xam nhap vao cacdang nguyen lieu giau ng va giau am, no nhan len trong o va tien hanh len

men lactic ngay ga khoi nguyen lieu. Khi muoi chua rau, cu hoac u chua tht,sa, neu lam ung cach t la a at c ba muc ch- Thuc ay s phat trien manh me cua cac te bao vi khuan lactic, tao ra mot

lng sinh khoi ln, giup chung lan at c s gay nhiem cua bon tap khuan gayoi thoi

- Gay chua nguyen lieu do co s tch luy mot lng ang ke axit lactic trongmoi trng, nh vay tao nen v thm ngon cua san pham

- Chuyen rau, cu, tht, sa ve dang chn sinh hoc, do vay chung co khanang t bao quan- ngha la co the duy tr c lau hn nhieu so vi nguyen lieuban au.

Ngay nay, do trnh o khoa hoc ky thuat a nang cao, nen ngi ta khong chs dung bien phap len men Lactic theo kieu dan gian, ma co the phan lap e tachlay cac giong vi khuan lactic thuan khiet roi chu ong cay vao nguyen lieu theo ymuon.

Cac vi khuan lactic c xep chung vao ho Lactobacteriacae bao gom haichi, moi chi co mot so noi thng gap. Theo he thong phan loai cua Bergey th cacvi khuan lactic c phan chia nh sau:



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Lactobacteriacae

Streptococcacae

Thermobacterium

Lactobacterium

BetabacteriumStreptococcus

StreptobacteriumLeuconostoc

ieu kien thch hp cho s sinh trng va hoat ong len men cua vi khuanlactic la:

+ Nhiet o t 20 22oC+ PH 3 4,5

+ Nong o muoi an (NaCl): 2 3%

+ Nong o ng: 1 2%

+ K kh hoac vi hieu kh.

Len men lactic la mot trong nhng qua trnh sinh hoa n gian, trong odien ra chuyen hoa k kh ng thanh acid lacic, di tac ong cua mot enzyme

co trong moi te bao vi khuan thuoc nhom lactic va khong co cac loai VSV khac.;o laLactat dehydrogenaza . Can c vao c che phan ng va loai san pham hnhthanh, ngi ta chia qua trnh len men lactic thanh hai phng thc nh sau:

len men lactic ong hnh (Homofermentation)

Phng thc nay do nhom vi khuan lactic ong hnh thc hien san phamlen men cua chung cha ti 90 98% acid lactic. Cac san pham phu con lai khongang ke.

Phng thc len men lactic d hnh (Heterofermentation)

Phng thc nay do vi khuan len men lactic d hnh thc hien san phamlen men rat a dang trong o acid lactic ch chiem 40 45%, con lai la cac sanpham phu khac, bao gom etanol 20%, acid acetic 10%, cac chat khac 5 10%.



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C che len men lactic d hnh t c ng dung trong cong nghiep, nhngtrong cac loai thc an muoi chua theo phng phap dan gian th thong ton taisong song ca hai qua trnh nay.

C che tong quat cua s len men dien ra nh sau:

CH3CO COOH

NAD H+ 2 H+

2NAD+

C6H12O6 2CH3- CH CHOH COOH

(acid lactic)V du: Dien bien sinh hoa cua qua trnh len men lactic trong cac san pham rau cu,qua muoi chua theo phng phap dan gian thng trai qua 3 giai oan nh sau:

Giai oan 1: Muoi an (NaCl) co mat trong moi trng vi nong o 2 3%lam cho ap suat tham thau lp dch ben ngoai tng oi cao, tao nen traang thaiu trng, do vay, ng va cac chat dinh dng co trong cac te bao rau, cu, quakhuyech tan vao moi trng. Vi khuan lactic t khong kh du nhap vao nguyenlieu gap ieu kien thuan li ve dinh dng se nhan len nhanh chong. Luc naylng acd lactic con t v toc o len men con cham chap.

Giai oan 2: Quan the vi khuan lactic phat trien manh me, toc o len mendien ra ao at, lng acid lactic tch tu nhanh va nhieu, o pH trong khoi nguyenlieu giam ti 3 3,5. khoang pH nay, ch thch hp vi vi khuan lactic, con cacvi khuan gay thiu, gay thoi khac lai b c che, nh vay vi khuan lactic ngay cangco v tr ap ao ve so lng va dan dan chiem u the tuyet oi.

Thc pham giai oan nay co hng v thm ngon ac trng va co mausac kha hap dan. Trang thai chn sinh hoc cua nguyen lieu ung o oi u. ayla giai oan quan trong, v no quyet nh chat lng san pham. Neu khong tao

c trang thai len men toi u th de xay ra hien tng khu oi vi rau, cu, quava Thiu oi vi tht, sa.

Mot trong nhng nguyen nhan dan en khu va thiu thng vap phai la donong o muoi a vao khong thch hp.

Can nhan manh rang nong o 2 3% th vi khuan len men Butiric vanhom vi khuan E. coli b c che ma khong anh hng en hoat ong cua nhom vi



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khuan lactic, neu nh a nong o muoi len cao 5 6% th se c che s phat trienva s len men cua chnh vi khuan Lactic, ngc lai nong o di 3% th nhieutap khuan gay nhiem se nhan len c va canh tranh vi vi khuan Lactic. Nguyennhan th hai dan en ngng tre qua trnh len men Lactic la do khong tao c

ieu kien k kh. Neu e khong kh lot vao khoi nguyen lieu se khien cho nhom vikhuan Lactic khong tien hanh tot viec tch luy Acid Latic vao moi trng t odan en nguyen nhan th 3 la o pH khong am bao ngng can thiet. Ngi taa xac nh c cac khoang pH thch hp cho cac oi tng VSV co lien quanen qua trnh len men nh sau:

+ Vi khuan gay thoi hoat ong pH 4,4 5

+ Vi khuan gay benh ng ruot hoat ong manh pH 5 5,5

+ Nam men gay nhiem da, ca, sa, tht hoat ong manh pH 2,5 3

+ Nam moc gay nhiem hoat ong pH 1,2 3Trong khi o vi khuan Lactic thch hp nhat vi pH 3 4,5. do vay can

duy tr khoang pH nay trong suot khoang thi gian bao quan san pham.

Giai oan 3: Luc nay do lng acidLactic a c tch tu vi mot lngkha cao nen pH giam xuong di 3, do vay ban than cac vi khuan Lactic b c che.Neu c e t nhien th luc nay nhom nam menva nam moc gay nhiem bat auhoat ong manh, hai oi tng nay co kha nang phan huy acidLactic thanh CO2va H2O do vay lam cho san pham b giam, chat lng trong khoi nguyen lieu bat

au co hien tng noi vang, noi bot kh va mat i mui thm cua giai oan trc. Vthe, neu la thc an che bien e dung cho gia nh th can tieu thu het trc khi quatrnh len men chuyen sang giai oan 3. con neu la trong san xuat cong nghe thngi ta ngan chan hien tng tren bang cach lu gi cac san pham len men nhiet o thap (2 40C) ong thi co bo sung them mot loai hoa chat sat trung naoo (v du: benzoat natri vi nong o 1%, dch chiet cu toi, dch chiet cu rieng

Khi an cac san pham a c che bien theo phng phap Lactic hoa, cthe a ong thi tiep nhan ca mot lng ang ke sinh khoi vi khuan lactic, motlng nho acid Lactic va nhng chat dinh dng von co cua nguyen lieu. acidLactic cung vi vi khuan Lactic la nhng nhan to giup ch ac lc cho qua trnhtieu hoa, gay ngon mieng va gop phan duy tr tot s can bang cua khu he VSV coli c tru trong ng ruot cua c the ngi va ong vat. Nh a noi tren, cac loaithc pham c bao quan bang phng phap Lactic hoa bao gom 3 nhom:

+ Cac loai rau, cu, qua, da chuot, da leo, cu cai, su hao, cai bap, caixanh,ca, sup l, nam m, nam rm



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+ Cac loai tht va sa ong vat

+ U chua cac loai co, rm, rau dung lam thc an cho gia suc.

2.Mot so cong thc che bien va bao quan tht, sa, tom bang len men Lactic

Can noi them rang, khi ap dung nhng cong thc nay ,cac ban nen chu y tnhlinh hoat sa oi nhng chi tiet nho e phu hp vi ieu kien cu the trong gia nhhoac trong xng san xuat cua ban. Khong co mot cong thc hoac mot cong trnhcong nghe nao la tuyet oi ung cho moi trng hp

a. San xuat sa chua (Yaourt)

* Nguyen tac

Sa chua la mot loai thc pham truyen thong va pho bien cac vung co nghechan nuoi bo sa (hoac de, cu , lac a)

T nguyen lieu ban au la sa bo , nh s hoat ong cua cac vi khuan lenmen lactic , qua trnh len men dien ra theo hng lactic hoa moi trng ong thigay ong tu protein co trong sa, ket qua la sa chuyen t trang thai long sangtrang thai keo set. San pham trang thai chn sinh hoc tr nen co hng v acbiet hi chua va rat thm ngon.

Khi an sa chua, tom chua, nem chua, ta ong thi ta ong thi s dung ca

sinh khoi vi khuan Lactic va mot lng nho vi khuan Lactic co trong san pham dovay loai thc an nay va cung cap chat dinh dng lai va co tac dung kch thchtieu hoa va gi can bang cho he vi khuan ng ruot.

e san xuat sa chua, co the dung sa ti, sa bot, sa ac co ng (sahop)



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Cong thc phoi che nguyen lieu:

Sa ti 1 lt

ng Saccharose 150 300 g (tuy khau v)

Muoi an 5 10 gYaout cai 100 200 g

Ghi chu:

1.co the thay the sa ti bang sa bot (300 400 g) hoaac sa hop (300 400 ml)2.Co the thay Yaourt cai bang cach cay vi khuan giong thuan (mot ong thach ng

pha trong 100 ml dch hoat hoa)

- Pha moi trng e lam dch hoat hoa vi khuan Lactic theo cong thc sau:

Lactamin (hoac pepton) 20 gng Saccharose 20 g

K2HPO4 2 g

MgSO4.7H20 0,58 g

MnSO4.4H2O 0,28 g

Acid Citric 2 g

Nc chiet gia au 10%

Bo sung nc u u 1 lt

- Moi trng e nuoi cay vi khuan Lactic tren thach ng giong nh tren nhng co bosung Agar (20 g)



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* Quy trnh che bien

Sa ti ( + ng va muoi , un nhe 800C)

Moi trng len men+ Yaourt cai hoac giong vi khuan lactic, hoa tan, ong ly 8 16gi, e 40 500C, ay kn e gi k kh

Ban thanh pham

gi on nh lam lanh 5 100C, 2 3 gi Thanh pham sachua (Yauort), neu e tu lanh co the bao quan trong 7 -10 ngay

San pham

- San pham lam ra phai co mau trang nga, hi chua, ngot nhe, co muithm ac trng, trang thai ong set va ong nhat.

- Neu thay co mui hoi hoac b va va ong von la b nhiem vi khuan la,khong nen dung

* Tieu chuan chat lng

+ Nitrogen toan phan 7,2 g/l

+ Acid Lactic 5 10 g/l

+ ng toan phan 40 70 g/l+ Vitamin A,B,C,D

+ Khong co sinh vat gay benh

b. San xuat mam tom chua (hoac tep chua)

* nguyen lieu chnh:

- Tom nc ngot cat bo au- Tep nc ngot nhat ky e loai bo san, oc - Ra sach, e rao nc

* Cong thc phoi che:

Tom ti hoac tep ti 1 kg

ng knh (Saccharose) 250 350 g



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Muoi an NaCl 200g

Thnh gao rang (a xay mn) 100 200 g

Ru trang 30 45o 100 200 ml

Toi, t, tieu (tuy khau v)* Quy trnh che bien.

Nguyen lieu a x ly

+ Bo sung them 100 ml ru, ng, muoi, thnh gao

+ Tron eu, ay nap (phi nang)

Len men Lactic t nhien 7 15 ngay nhiet o 30 35 0C

Ban thanh pham

+ Bo sung toi, t, tieu, u co nh 1 2 ngay

San pham

+ San pham lam ra phai co mau o ti, co v hm ac trng, co v chua,ngot, man hoa hp. Neu thay co mui la la b nhiem, phai bo i.

* Tieu chuan chat lng

+ Ham lng chat kho 30%

+ Nitrogen toan phan 20 g/l+ Nitrogen formol 5 g/l

+ Muoi an NaCl 200 300 g/l

+ ng toan phan 50 g/l

+ Acid Lactic 3 15 g/l

+ Khong nhiem Vi sinh vat gay benh.

Ghi chu: Neu co lam mam theo kieu ngi Hue th khong cho thnh gao,

ong thi co bo sung u u bao nho vao thi iem 1 ngay trc khi an.Loai mam nay co the bao quan 1 thang ke t khi nguyen lieu at trang

thai chn sinh hoc.



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c.San xuat nem chua.

* Nguyen lieu chnh:- Tht ln nac, loai m, co bo sung b ln luoc thai nho- Muoi diem tieu (KNO3)- La vong nem hoac la oi* Cong thc phoi che: Tht nac loai m 1 kg

B ln luoc thai nho 200 300 g

ng knh (Saccharose) 200 300 g

Muoi an NaCl 200 300 gKNO3 (diem tieu) 5 10 g

Toi, tieu, t (tuy khau v)

Ru trang 30 45o 5 10 ml

Thnh gao xay mn 100 200 g

La vong nem hoac la oi , La chuoi

* Cach lam:

- Tht heo xay hoac gia nho- Phoi che nguyen lieu, tron eu goi mot lp la vong hoac la oi, sau o bao kn bang

la chuoi

- Bo cang chat tay cang tot- Buoc lat hoac giay nylon- Treo cho thoang, am, gi nhiet o 28 320C trong 2- 4 ngay



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* Quy trnh che bienTht heo nac

+ Xay nho

+ Tron vao b

Hon hp nghien mn

+ ng, muoi, diem tieu, thnh, ru, gia v

+ ay vai man, e yen 1 2 gi(e vi khuan Lactic xam

nhap vao nguyen lieu)Moi trng len men (nem ti)

Len men Lactic 28 320C 2 4 ngay ,

Boc la vong, la oi. Bao goi la chuoi

Nem chua thanh pham

- San pham phai co mau o nau, co v thm ac trng. Nem phai ket thanh motkhoi deo dai, ong nhat, chac chan.

- Nem gi tu lanh co the bao quan c 15 ngay ke t khi chn sinh hoc.

III. LEN MEN ACETIC VA NG DUNG.

1. C che ly thuyetC chat thch hp nhat cua VK Acetic la ru Etilic. Ban chat cua QT len men Acetic lamot qua trnh Oxy hoa khong hoan toan , dien ra theo c che tong quat sau:

Alcohol-dehydrogenaseCH3-CH2- OH + O2 CH3-COOH + H2O + xKCAl

Co hai nhomVK Acetic, thc hien oxy hoa hai mc khac nhau :- VK Acetobacter peroxidans thc hien QT Oxy hoa cao, Acetic ch la san pham tam

thi, sau o no c Oxy hoa tiep thanh cac san pham khac.



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- VK Acetobacter suboxydans thc hien QT Oxy hoa thap, san pham cuoi cung laAxit Acetic, c tch luy ben trong moi trng. Nhom nay oc s dung nhieu trongCN san xuat dam an va thach da.



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Qua trnh phan ng gom hai lan loai Hydro lien tiep( Oy hoa c chat nh s xuc tac cua cac E. Dehydrogenaza)

Dien bien sinh hoa dc trnh bay theo s o di ay

S o Qua trnh len men Acetic (Vi khuan Acetobacte aceti)

E. Alcohol-dehydrogenase

CH3-CH2- OH CH3 - CHO (acetaldehit)NADPH2

+ H2O

OH

CH3 - CHOHNADP+ (acetal hydrat)

E.Aldehyt-dehydrogenaseNADPH2

CH3-COOH (Axit Acetic)

2. San xuat dam an:

Dam an la dung dch Acid acetic nong o 6%- 8%.- Goc giong dung trong san xuat la

Acetobacter acetiAcetobacter oleanenseAcetobacter xylinum

- Nhiet o thch hp la 30 32 o C

- Nguyen lieu la ru trang hoac ru vang trai cay*/ Co the thay giong thuan bang cach cho len men t nhien, co bo xung mot

lng nho Axit Acetic e lam moi :- Vang nho 40ml- Acid acetic 20ml- nc chn u 1lit


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