San Xuat Xanthangum

XANTHAN GVHD: PGS.TS. L VN VIT MN

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MC LC

1. GII THIU CHUNG V XANTHAN GUM ....................................................................... 4

1.1. Khi nim ......................................................................................................................... 4

1.2. Lch s ra i ................................................................................................................... 4

1.3. Cu to v tnh cht .......................................................................................................... 4

1.3.1. Cu to ...................................................................................................................... 4

1.3.2. Tnh cht ................................................................................................................... 7

1.4. Tnh hnh s dng mt s loi polysaccharide ................................................................. 8

2. NGUYN LIU ...................................................................................................................... 9

2.1. Vi sinh vt ........................................................................................................................ 9

2.1.1. Phn loi.................................................................................................................... 9

2.1.2. c im hnh thi .................................................................................................. 10

2.1.3. Tiu ch chn ging ................................................................................................ 10

2.2. Mi trng ln men ........................................................................................................ 11

2.2.1. Ngun Carbon ......................................................................................................... 11

2.2.2. Ngun Nito.............................................................................................................. 11

2.2.3. Ngun khong v yu t sinh trng ...................................................................... 12

2.3. Nc ............................................................................................................................... 13

2.4. Mui cng nghip v cn tinh luyn .............................................................................. 14

3. QUY TRNH CNG NGH SN XUT XANTHAN GUM ............................................. 15

3.1. Nhn ging ..................................................................................................................... 17

3.2. Chun b mi trng ln men ......................................................................................... 18

3.3. Ln men .......................................................................................................................... 20

3.4. Thanh trng .................................................................................................................... 24

3.5. Tch vi sinh vt .............................................................................................................. 26

3.6. Kt ta ............................................................................................................................ 27

3.7. Tch nc ....................................................................................................................... 28

3.8. Sy .................................................................................................................................. 29

3.9. Nghin ............................................................................................................................ 30

3.10. ng gi ..................................................................................................................... 32


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4. CH TIU CHT LNG CA SN PHM XANTHAN GUM ..................................... 32

4.1. Ch tiu vt l ................................................................................................................. 32

4.2. Ch tiu ha l ................................................................................................................ 32

4.3. Ch tiu vi sinh ............................................................................................................... 32

5. TI LIU THAM KHO ..................................................................................................... 33


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DANH MC HNH

Hnh 1.1: Cu trc ca mt n v ca xanthan gum ..................................................................... 5

Hnh 1.2: Cu to ca xanthan gum ................................................................................................ 6

Hnh 2.1. Vi khun Xanthomonas campestris ................................................................................ 9

Hnh 2.2. Ci bp nhim vi khun Xanthomonas campestris ........................................................ 9

Hnh 3.1. S qui trnh cng ngh sn xut xanthan ................................................................. 16

Hnh 3.2. Thit b nhn ging ....................................................................................................... 18

Hnh 3.3. Thit b khuy trn ........................................................................................................ 19

Hnh 3.4. Thit b trao i nhit dng bn mng .......................................................................... 19

Hnh 3.5. Chu trnh ng phn ................................................................................................... 20

Hnh 3.6. Chu trnh Tricarbonxylic............................................................................................... 21

Hnh 3.7. S sinh tng hp xanthan .............................................................................................. 22

Hnh 3.8. Thit b ln men dng xilanh ........................................................................................ 23

Hnh 3.10. Thit b li tm .............................................................................................................. 26

Hnh 3.11. Thit b kt ta ............................................................................................................ 28

Hnh 3.12. Thit b p trc vt ....................................................................................................... 29

Hnh 3.13. Thit b sy bc x ...................................................................................................... 30

Hnh 3.14. Thit b nghin ba ..................................................................................................... 31

DANH MC BNG

Bng 1.1: Thnh phn % ca D glucose, D mannose, D Glucuronic acid, pyruvate, acetate

trong polysaccharide do mt s chng vi khun khc nhau to ra. ................................................ 6

Bng 1.2: T sut tng trung bnh hng nm ca nhng polysaccharide thng mi ch yu:

nhng d bo v phn tch ca th trng M. ............................................................................... 8

Bng 2.1. Ch tiu cht lng cn ................................................................................................ 14

Bng 2.2. Ch tiu cht lng mui .............................................................................................. 14


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1. GII THIU CHUNG V XANTHAN GUM

1.1. Khi nim

Xanthan gum l mt polysaccharide c s dng nh l mt ph gia thc phm v cht iu chnh lu bin. L sn phm ln men ca glucose v saccharose bi vi khun Xanthomonas campestris.

Xanthomonas campestris l loi vi khun gy ra bnh mc en trn ci, hoa l v

cc loi rau l mng khc.

1.2. Lch s ra i

Cch y rt lu, con ngi tm hiu c rng cc loi Xanthomonas c th sn xut ra nhng khi sn st.

Cui nm 1950, xanthan c pht minh ti Northern Reaseach Center (NRRC), Peoria, Illinois.

B Allene Rosalind Jeanes v cng s ca b Vin Nng Nghip Hoa K (United States Department of Agriculture) t chc cuc kim tra cc loi vi sinh vt c kh nng sn xut ra cc loi gum tan trong nc, trong s , xanthan l mt polysaccharide tng hp bng phng php sinh hc m c tim nng ng dng rt ln so vi cc loi gum tan trong nc c sn xut bng phng php t nhin.

u nhng nm 1960, xanthan tr thnh sn phm thng mi bi cng ty Kelco vi tn thng mi l Kelzan (theo Whistler) nhng khng thch hp cho thng mi mi n nm 1964.

Nm 1969, xanthan c t chc FDA (the American Food and Drug Administration) cho php s dng lm ph gia thc phm sau nhng nghin cu v th nghim trn ng vt. N c php s dng cc nc: Hoa K, Canada, Chu u (1982). S k hiu l E415.

Cc cng ty sn xut xanthan ni ting: Merck, Pfizer v Kelco ca M, Rhne

Poulenc v Sanofi-Elf ca Php, Jungbunzlauer ca c.

1.3. Cu to v tnh cht

1.3.1. Cu to

1.3.1.1. Cu to phn t

Xanthan bao gm nhng cm 5 gc ng c lp li, mi cm gm 2 gc ng D - glucose, 2 gc ng D - mannose, 1 gc ng D - glucoronate v cc gc acetate, pyruvate vi s lng thay i.

Mi cm n v ca mch chnh trong chui polysaccharide bao gm cc gc - D - glucose, lin kt vi nhau bng lin kt - 1, 4 glycoside. Yu t ny ging vi cu trc ca cellulose.


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Mch nhnh gm 1 gc glucoronate nm gia lin kt vi 2 gc mannose. V tr th nht ca gc D-glucoronate lin kt vi v tr th hai ca 1 gc D - mannose, cn v tr th t ca gc D-glucoronate lin kt vi v tr th nht ca mt gc mannose khc.

Mch nhnh lin kt vi mch chnh ti v tr th 3 trn gc cellulose ca mch chnh v v tr th nht trn gc mannose ca mch nhnh.

Khong mt na s gc mannose cui c nhm acid pyruvic lin kt do nhm ketal to vng ti v tr 4 - 6 trn gc mannose.

Gc mannose cn li lin kt vi mt acetyl ti v tr th 6.

Xanthan gum cng cha cc ion dng ha tr mt nh l Na, K.

Mch nhnh v mch thng xon cht vi nhau to thnh hnh dng bn cht.

Hnh 1.1: Cu trc ca mt n v ca xanthan gum

1.3.1.2. Khi lng phn t

Khi lng phn t c th t 0.9 triu n 1.6 triu Dalton, n ph thuc vo ngun

VSV v iu kin thc hin qu trnh ln men.

i khi khi lng phn t xanthan c th ln n 13 50 triu Dalton.


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Hnh 1.2: Cu to ca xanthan gum

1.3.1.3. Trng thi phn t

Xanthan l phn t sinh hc xon i nhng khng i xng nhau.

Mch nhnh v mch thng xon cht vi nhau to thnh hnh dng bn cht.

Cc phn t c th co li hnh xon c kp hnh thnh nn cu trc c qunh,

khi gp mt s iu kin s b dui mch lm thay i tnh cht.

Mch chnh c mch bn bo v nn lm cho xanthan tng i bn vi acid,

kim v enzyme.

1.3.1.4. Thnh phn cu to

Acid pyruvic l mt thnh phn rt quan trng do n tc ng n kh nng ha

tan trong nc ca polymer. Thnh phn acid pyruvic trong xanthan khc nhau ph thuc

vo chng Xanthomonas campestris (c nhng chng sn xut ra hm lng acid pyruvic

rt cao, c nhng chng li sn xut ra vi hm lng rt thp), iu kin ln men v iu

kin thu hi sn phm.

Bng 1.1: Thnh phn % ca D glucose, D mannose, D Glucuronic acid, pyruvate, acetate trong polysaccharide do mt s chng vi khun khc nhau to ra.

Vi khun D - Glucose

D -

Mannose

D Glucuronic

Acid

Pyruvate Acetate

X.campestris 30,1 27,3 14,9 7,1 6,5

X.vasculorum 34,9 30,2 17,9 6,6 6,3

X.faseoli 30,9 28,6 15,3 1,8 6,4

X.juglandis 33,2 30,2 16,8 6,9 6,4

X.gummisudans 34,8 30,7 16,5 4,7 10

X.fragaria 24,6 26,1 14 4,9 5,5


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1.3.2. Tnh cht

1.3.2.1. To dung dch c nht

Khi ha tan trong nc, b hydrate ha mt cch nhanh chng, khng b ng

cc to dung dch c nht cao.

Xanthan gum c nht cao. Dung dch c nng khong 1% c nht xp x

1000 cP khi o 60 v/ph vi thit b o nht Brookfield model LVF 250C.

nh hng ca mui: nht khng b nh hng khi thm mt lng ln mui,

nh trong 250 g/l dung dch NaCl ch lm tng khng ng k nht ca dung dch

xanthan.

1.3.2.2. Tnh tng hp ca xanthan

Vi alcohol

Tuy xanthan khng ha tan trc tip c trong alcohol nhng li c kh nng

tng thch vi n. Nhng sn phm c cha xanthan trong cng thc thnh phn thng

chim n 60% dung mi alcohol nh ethanol. Ta c th s dng tnh cht ny lm

cho cocktail, ru c mi chocolate tr nn c hn.

Vi cc loi enzyme

Hu ht cc dung dch keo u b thoi ha mt gii hn no bi cc enzyme

c mt trong thc phm nh cellulase, pectinase, amylase, protease. Tuy nhin, xanthan

khng b thoi ha bi chng. Kh nng khng li tc ng ca enzyme l do s xp xp

cc nhnh chnh v nhnh ph, s xp xp ny chng li tc ng ca enzyme ln lin kt

1,4 trong nhnh chnh. Nh m ngn cn c s ngng trng hp do enzyme, acid v

kim. ng dng thc t, kh nng xanthan chng li tc ng ca enzyme c s

dng trong mt s sn phm thc phm nh bnh mt to, thc phm c cha tinh bt,

gia v trn

1.3.2.3. Gel thun nghch v nhit

Gel to thnh khi lm ngui cc hn hp. Xanthan gum trng thi keo c th

thc hin s chuyn i cu hnh xon c i thnh chui n bng cch ti luyn nhit

40 - 800C. cu hnh chui n, mng li lin kt yu i, hnh thnh nn trng thi

gi do (pseudoplastic) lm gim nht ca dung dch. Xanthan gum c kh nng kt

hp c vi nhiu cht to gel, to st khc nhau nh locust bean gum, konjac, guar

gum.


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1.3.2.4. Kh nng hydrate ha

S hin din ca nhng chui tch in m trong phn t xanthan gum lm tng kh

nng hydrate ha v to nn dung dch xanthan trong nc lnh. Xanthan gum l mt cht

ho nc, tan c trong nc nng v nc lnh. iu kin lnh ng/r ng: nh kh

nng lin kt vi nc nn dung dch xanthan gum rt bn khi lnh ng cng nh r ng.

1.4. Tnh hnh s dng mt s loi polysaccharide

C rt nhiu loi polysaccharide c sinh tng hp bi vi sinh vt nh alginate,

curlane, dextran, gellan, glucan, pullulan v xanthan.

Trong s nhng loi ny th xanthan c vai tr vt tri hn bi d dng sn xut

v c ng dng nhiu. Thc vy, n ang dn c s dng nhiu trong thc phm v

trong vic to ra cht n cho m phm.

Trong cng nghip polysaccharide th xanthan l mt trong nhng i din pht

trin nhanh nht.

i vi ngnh thc phm, nhng nhu cu v gum t nhin ang c xu hng gim

xung, trong khi xanthan li c xu hng tng ln.

Khong 20.000 tn xanthan c sn xut theo phng php cng nghip t ging

vi khun X. campestris mi nm. Nhu cu tiu th xanthan trn ton th gii l khong 23

triu kg/ nm v c d on l s tip tc tng ln 5-10% theo hng nm.

Bng 1.2: T sut tng trung bnh hng nm ca nhng polysaccharide thng mi ch yu: nhng d bo v phn tch ca th trng M.


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2. NGUYN LIU

2.1. Vi sinh vt

Xanthan c sn xut t vi khun Xanthomonas campestris c c lp t cy ci

bp, n chnh l loi vi khun gy ra bnh nm lm cho cy c mu en.

2.1.1. Phn loi

Vi khun Xanthomonas campestris:

Gii:

Ngnh: Proteobacteria

B: Gamma Proteobacteria

H: Xanthomonadaceae

Ging: Xanthomonas

Hnh 2.1. Vi khun Xanthomonas campestris

Hnh 2.2. Ci bp nhim vi khun Xanthomonas campestris


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2.1.2. c im hnh thi

Vi khun Xanthomonas campestris c dng hnh que n, thng. Rng 0.4 0.7m,

di 0.7 1.8 m.

Vi khun Gram m.

C kh nng di ng nh tin mao mc cc.

L loi vi khun d dng, hiu kh bt buc.

Khng c kh nng kh nit, phn ng catalase dng tnh, oxidase m tnh.

Pht trin trn mi trng dinh dng agar, b c ch bi 0,1% triphenyltetrazolium

chloride.

Phn ln chng sng mt mnh hoc theo tng cp. X. campestris lm thnh m

mucoid mu vng, trn nhn sng trn mi trng rn, v nhng t bo c bao quanh

bi xanthan gum (polysaccharide ngoi bo). Cng thc ha hc ca sc t vng c xc

nh l mono hoc dibromoaryl polyene.

Tnh khng n nh thuc v di truyn ca vi khun X. campestris s nh hng n cht lng cng nh s lng xanthan xut hin khi nui cy n. S t bin gene c lin quan n vic hnh thnh 3 dng khc nhau: L (large) v S (small) v VS (very small). Trong khi dng L sn xut ra mt lng ln xanthan vi cht lng thp mong mun th dng S li cho lng sn phm t v cht lng th km. Cn VS khng tng hp xanthan.

Nhng chc nng ca xanthan cha c nhn bit y , nhng c mt bng chng chc chn rng c mt lp polysaccharide xung quanh mng t bo, bo v t bo trnh khi nhng tc ng ca mi trng xung quanh. V d nh kh nng gi nc ca xanthan, n s cung cp mt lp mng bo v di iu kin mi trng hanh kh.

2.1.3. Tiu ch chn ging

Ging vi khun s dng phi t nhng chun mc nht nh mi c php s dng. Cc yu t c bn i vi ging vi khun s dng ln men thu nhn xanthan gm:

Ging vi khun phi c kh nng sinh tng hp xanthan mnh, sn phm ny c cht lng v s lng cao hn hn cc sn phm ph khc trong qu trnh trao i cht ca chng.

Ging phi c kh nng s dng cc nguyn liu r tin, d kim.

Ging vi khun c tnh thch nghi cao, c bit phi thch nghi vi iu kin sn xut cng nghip, trong c s n nh v nhit , pH,

Ging phi c tc sinh sn v pht trin rt mnh trong iu kin mi trng cng nghip. Tnh cht ny rt quan trng v khi nhim vi sinh vt l th ging dng trong sn xut phi c kh nng t ch s pht trin ca vi sinh vt l.


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Ging phi n nh trong bo qun v d dng bo qun.

2.1.4. Mi trng nhn ging.

Mi trng nhn ging quy m phng th nghim: dch malt trong ng thch nghing

cha:

10 g/l glucose.

5 g/l peptone

3 g/l dch chit nm men.

20g/l agar.

Mi trng nhn ging quy m cng nghip:

K2HPO4 : 5 g/l

MgSO4.7H2O: 0,1 g/l

Dch chit nm men: 0,5 g/l

Ure : 0,4 g/l

Glucose: 20 g/l

2.2. Mi trng ln men

2.2.1. Ngun Carbon

Glucose v saccharose l hai ngun carbon c s dng ph bin cung cp

cho vi khun Xanthomonas campestris trong qu trnh ln men thu nhn xathan. Trong

glucose l ngun carbon vi khun Xanthomonas campestris d s dng. Tuy nhin,

nng cao n li nh hng xu ti qu trnh ln men ca vi khun, theo cc nghin

cu th khi nng glucose 2 -4% w/w l mi trng l tng cho qu trnh ln men.

thun tin v ch ng cho vic sn xut, ta dng syrup glucose lm ngun

cung cp carbon cho vi khun. Syrup glucose s c chun b sn v cn phi c

kim tra trn nhng ch tiu sau:

- Ch tiu cm quan: mu sc, trong, mi v,

- Ch tiu ha l: ch s DE, tng hm lng cht kh, chua, nht,

- Ch tiu vi sinh: tng s vi khun hiu kh, nm men v nm mc.

2.2.2. Ngun Nit

Vi khun Xanthomonas campestris c th s dng c c ngun nito hu c v

ngun nito v c. V vy m ta c th dng nc ngm ht ng cc, dch thy phn

casein, dch chit nm men, dch chit t u nnh, tuy nhin ngun nito thng c

s dng nht l mui amoni trong mi trng nhn ging v nitrat trong mi trng

ln men. Xanthan c sn xut c cht lng tt nu X. campestris c nui dng

trong mt mi trng tng hp n gin gm NH4Cl, glucose v mui.


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2.2.3. Ngun khong v yu t sinh trng

Ngoi vic cung cp cc nguyn t c bn th qu trnh ln men c din ra

tt nht ta cng cn cung cp y cho vi khun cc nguyn t khong v cc yu

t sinh trng.

Cc mui v c l ngun cht dinh dng khng th thiu i vi s sinh trng

ca vi sinh vt. Chng c cc chc nng sinh l ch yu l: tham gia vo thnh phn

ca cc trung tm hot tnh cc enzyme ca vi sinh vt, duy tr tnh n nh ca kt

cu cc i phn t v t bo, iu tit v duy tr cn bng p sut thm thu ca t

bo, khng ch in th oxy ho kh ca t bo v l ngun vt cht sinh nng lng

i vi mt s loi vi sinh vt.

Bng 2.3: Mui v c v chc nng sinh l ca chng

Nguyn

t Hp cht s dng

Chc nng sinh l Tiu chun k

thut

P

KH2PO4,

K2HPO4

L thnh phn ca acid nucleic, nucleoprotein, phospholipid, coenzyme,

ATP... Lm nn h thng m gip iu chnh pH mi trng.

S

(NH4)2SO4,

MgSO4

L thnh phn ca cc aminoacid cha S, mt s vitamin; glutathione c tc dng iu

chnh in th oxy ho kh trong t bo.

Mg MgSO4

L thnh phn trung tm hot tnh ca enzyme phosphoryl ho hexose,

dehydrogenase ca acid isocitric, polymerase ca acid nucleic, thnh phn ca

chlorophyll v bacterio-chlorophyll.

Ca

CaCO3

CaCl2,

Ca(NO3)2

To tnh n nh ca mt s cofactor, enzyme duy tr, cn cho s dng trng thi

cm th ca t bo.

TCVN

3912:1984

Na

NaCl

Thnh phn ca h thng chuyn vn ca t bo, duy tr p sut thm thu, duy tr tnh n

nh ca mt s enzyme.

K KH2PO4

L cofactor ca mt s enzyme, duy tr p sut thm thu ca t bo, l nhn t n nh

ca ribosome mt s vi khun a mn.

Fe

FeCl3.6H2O

FeS04

Thnh phn ca sc t vi khun v mt s enzyme, l vt cht ngun nng lng ca mt s vi khun st, cn thit tng hp chlorophyll v c t vi khun bch hu.


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Trong qu trnh sinh trng vi sinh vt cn cn ti mt s nguyn t vi lng nh: Zn, B.

Nhng nguyn t ny cng c vai tr quan trng mc du ch cn vi s lng rt nh, khong

10-8

-10-6

mol/ L mi trng nui cy. Nguyn t vi lng tham gia vo thnh phn enzyme v

lm hot ho enzyme.

Cc cht h tr k thut nh cht chng bt(QCVN 4-7:2010/BYT - Quy chun k thut

quc gia v ph gia thc phm - Cht chng to bt), cht iu chnh pH: acid citric (QCVN

4-11 : 2010/BYT- quy chun k thut quc gia v ph gia thc phm cht iu chnh acid)

2.2.4. Cng thc phi trn

Glucose: 30g/l

MgSO4.7H2O: 0,24g/l

(NH4)2SO4: 3,33g/l

H3BO3: 0,0072g/l

FeCl3.6H2O: 0,0042g/l

KH2PO4: 7,2g/l

CaCO3: 0,029g/l

Acid citric: 2g/l

ZnO: 0,006g/l

Dch chit nm men: 0,75 g/l

Peptone: 0,34 g/l

Cht chng bt: 0,06 g/l

pH ban u: 7,0

2.3. Nc

Nc c s dng trong quy trnh sn xut xanthan c hai vai tr l:

- Pha long mi trng nhn ging v mi trng ln men ti nng thch

hp cho s sinh trng ca vi khun tng qu trnh.

- Nc c s dng pha long canh trng sau ln men gim nht,

tng hiu qu tch t bo vi khun qu trnh ly tm pha sau.


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Nc s dng trong quy trnh sn xut cn phi t c nhng ch tiu sau:

- cng chung (mg ng lng) 7

- Hm lng mui carbonate 50 mg/l

- Hm lng mui Mg 100 mg/l

- Hm lng mui clorua: 75 150 mg/l

- Hm lng mui CaSO4: 130 200 mg/l

- Hm lng Fe2+ 0.3 mg/l

- Kh NH3 : khng c

- Cc mui c gc NO-, NO2-: khng c

- Vi sinh vt 100 t bo/1 cm3

2.4. Mui cng nghip v cn tinh luyn

Mui v cn l ph liu cn thit cho qu trnh kt ta ca xanthan. m bo cho

cht lng ca sn phm xanthan th mui v cn cn t nhng tiu chun sau:

Bng 2.1. Ch tiu cht lng cn

STT Tn ch tiu n v o Yu cu

1 Ethanol % v/v Khng thp hn 96,2

2 Aldehyde tng mg/l Khng vt qu 4

3 Ru cao phn t mg/l Khng vt qu 4

4 Ester mg/l Khng vt qu 30

5 Methanol PP th vi fuchsin acid m tnh

6 Acid hu c mg/l Khng vt qu 15

7 Fufurol Khng c


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Bng 2.2. Ch tiu cht lng mui

Tn ch tiu Yu cu

Mu sc Mui tinh ch, tinh th mu trng u, sch, khng c tp cht.

Khi ha tan trong nc phi c dung dch trong, ng nht

Mi Khng c mi

Dng bn

ngoi

Kh ro, ti u, trng sch

C ht 115 mm

m < 10%


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3. QUY TRNH CNG NGH SN XUT XANTHAN GUM

Hnh 3.1. S qui trnh cng ngh sn xut xanthan

Sy

Nghin

Sn phm

Bao b

Thanh trng

Pha long

Tch t bo VK

Kt ta

Tch nc

Xc VK

Nguyn liu

Chun b mi trng

Ging vi khun

Nhn ging

Ln men

ng bao b


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3.1. Nhn ging

Mc ch: chun b cho qu trnh ln men.

Qu trnh nhn ging nhm mc tiu thu nhn c s t bo cao hay ni cch

khc sn phm ca qu trnh l sinh khi( thng tnh l tng lng t bo/ml). N cn

c mc ch chun b cho qu trnh ln men tip theo c din ra tt hn.

Cc bin i:

- Ha sinh: Trong qu trnh nhn ging vi sinh vt xy ra rt nhiu phn ng ha sinh

bn trong v bn ngoi t bo lm xut hin nhiu sn phm trao i cht, gp phn

lm thnh phn ha hc ca mi trng thay i lin tc theo thi gian cy.

- Ha l: Trong qu trnh nhn ging xy ra 1 s bin i v pha. Vic nhn ging

c thc hin trong iu kin hiu kh nn vic sc khng kh vo canh trng s

lm tng nng oxy ha tan trong pha lng.

- Vt l: Trong qu trnh sinh trng, 1 phn nng lng s ta ra ngoi di dng

nhit nng. Hin tng ny c th lm tng nhit canh trng khi nhn ging vi

sinh vt qui m ln. Do cn ch hiu chnh nhit ca canh trng trong

sut qu trnh nhn ging.

- Sinh hc: Cc t bo vi sinh vt s thc hin qu trnh trao i cht v sn sinh ra

nhiu th h t bo mi.

Thit b:

Trong sn xut, ty thuc vo th tch lm vic ca thit b ln men m lng

ging cy VSV cn cy s thay i t hay nhiu. Do , s cp nhn ging cng s thay

i cc nh sn xut thu c ng lng ging cn s dng. Nu th tch bnh ln

men cng ln th lng ging cy cng ln.

Nhn ging c chia lm hai giai on:

- Nhn ging phng th nghim: s dng cc ng nghim (cp 1), bnh tam gic hoc

erlen(cp 2 v 3), bnh nui cy(cp 4).

- Nhn ging phn xng: s dng cc bnh ln men cho mi trng lng. Bnh ln

men dng nui cy ging VSV c cu to tng t nh nhng bnh ln men dng

nui cy VSV thu nhn cc sn phm trao i cht. Thit b c dng hnh tr ng,

bn trong c cnh khuy v b phn sc kh. Nhit canh trng trong qu trnh

nhn ging c th hiu chnh c nh lp v o xung quanh thn tr thit b. Ngoi

ra, thit b cn c cc cm ng nhit , pH, oxy, gip cho cc nh sn xut d

dng theo di v iu khin qu trnh nhn ging theo phng php t ng nh s

h tr ca cc chng trnh phn mm.


18

Hnh 3.2. Thit b nhn ging

Thng s cng ngh:

- Nhit : ti u l 28 300C.

- pH trung tnh l ti u cho s pht trin ca X. campestris.

- Thi gian:

3.2. Chun b mi trng ln men

Mc ch: chun b cho qu trnh ln men. Mi trng c phi trn theo mt t l nht

nh m bo ngun dinh dng cho vi khun ln men. Sau khi c phi trn, mi trng

ny s c thanh trng m bo cho mi trng c v trng.

Bin i:

- Vt l: tng nhit ca dch.

- Sinh hc: c ch v tiu dit vi sinh vt.

- Ha hc: mt s phn ng ha hc di tc dng ca nhit c th xy ra nh

Maillard.

Thit b:

- Thit b khuy trn: thit bi c dng hnh tr ng, bn trong c cnh khuy. Thit b

c lm bng thp khng r. Trong qu trnh phi trn cnh khuy s hot ng lin


19

tc to hn hp ng nht. Tc cnh khuy tng i ln, v s to ra chuyn

ng trn quanh trc v chuyn ng theo phng thng ng rt mnh. Do ,

hn ch hin tng to xoy, cn lp thm cc thanh chn thnh thng. Cc thanh

ny cn c tc dng tng hiu qu khuy trn.

Hnh 3.3. Thit b khuy trn

- Thit b thanh trng: s dng thit b thanh trng bn mng.

Hnh 3.4. Thit b trao i nhit dng bn mng

B phn chnh ca thit b l nhng tm bng hnh ch nht rt mng, lm bng

thp khng r. Mi tm bng c 4 l ti 4 gc v h thng cc ng rnh trn khp b mt

to s chy ri v tng din tch truyn nhit. Khi ghp cc tm bng mng li vi nhau

trn b khung ca thit b s hnh thnh nn nhng h thng ng vo v ra cho cht lng

cn thanh trng v cht ti nhit.


20

Thng s cng ngh:

Nhit thanh trng 70 750C

Thi gian thanh trng: 20 pht. Sau qu trnh thanh trng, mi trng c a v

nhit 25 -300C to iu kin thun li cho vi khun trong qu trnh ln men tip

theo.

3.3. Ln men

Mc ch: khai thc. Qu trnh ln men l qu trnh quyt nh to ra v thu nhn xanthan.

Bin i:

- Sinh hc: bin i quan trng trong qu trnh ln men l s trao i cht v s sinh

trng ca vi sinh vt, n cng tng t nh qu trnh nhn ging nhng xy ra mnh

m hn.

- Ha l: xy ra tng t nh qu trnh nhn ging.

- Vt l: trong qu trnh ln men, mt s ch tiu ca canh trng s thay i v

nht, t trng, Cn ch s gia tng nhit qu mc s lm gim hot tnh trao

i cht ca vi khun.

- Ha sinh: Qu trnh ln men sn sinh ra xanthan ca vi khun Xanthomonas

campestris l qu trnh ln men hiu kh. Qu trnh chuyn ha ng glucose thnh

xanthan c trnh by theo cc giai on sau:

Qu trnh ng phn l giai on phn hy phn t glucose to ra acid

pyruvic v NADH2. c chia lm 2 giai on:

Giai on u l phn ct ng glucose thnh 2 phn t ng 3C: AIPG

v PDA.

Giai on 2 l bin i ng 3C thnh acid pyruvic.

S :

Hnh 3.5. Chu trnh ng phn


21

Chu trnh Tricarboxylic xy ra trong c cht ty th nh s xc tc ca nhiu

h enzyme. Bn cht ca cc phn ng xy ra trong chu trnh ch yu l

decacboxyl ha v dehydro ha axit pyruvic. Chu trnh gm 2 phn:

Phn hy acid pyruvic to CO2 v cc coenzime kh.

Cc coenzime kh thc hin chui h hp to H2O v tng hp ATP.

Hnh 3.6. Chu trnh Tricarbonxylic

Chu trnh tng hp Xanthan

Tng t nh thc vt bc cao, vi sinh vt cng c kh nng tng hp ra

cc oligosaccharide v polysaccharide. Lng oligosaccharide v polysaccharide

ni bo chim n 60% khi lng kh ca t bo, cn polysaccharide ngoi bo

th vt nhiu ln khi lng ca t bo. Tt c cc oligosaccharide v

polysaccharide u c tng hp bng cch ko di chui saccharide c trc

nh vic thm n v monosaccharide.

Bc u tin ca qu trnh sinh tng hp xanthan l s hp th

carbonhydrate. Tip theo sau l qu trnh phosphoryl c cht bng enzyme

hexokinase c th s dng adenosine 5- triphosphat. S sinh tng hp c lin

quan n s chuyn i ca c cht c phosphoryl ho thnh cc loi

nucleotide ng khc nhau m i hi cn phi c s tham gia ca enzyme

UDP-Glcpyrophosphorylase ko di chui polysaccharide.

Trong X. campestris, chu trnh EntnerDoudoroff cng vi chu trnh

tricarboxylic acid l 2 c ch ch yu cho s d ha ng glucose. S sinh tng

hp xanthan, ging nh hu ht cc loi vi khun sn sinh ra polysaccharide, s

dng nhiu ngun carbonhydrate hot ha khc nhau tng hp nn polymer.

Xanthan c tng hp bng cch thm ln lt monossacharide vo

chui oligosacharide t ng nucleotide diphosphate cho n khi to thnh

phn t cht cho isoprenoid lipid. Mch chnh ca xanthan c hnh thnh t s


22

thm vo ca D glucose 1 - phosphate v D - glucose t 2 phn t UDP D -

glucose. Sau , D - mannose v D - glucoronic acid c thm vo t GDP -

mannose v UDP - glucoronic acid. Ln lt, nhm O-Acetyl c vn chuyn

t acetyl - CoA n phn mannose cn li.

Hnh 3.7. S sinh tng hp xanthan

C ch kt thc trong tt c nhng vi khun sn sinh ra polysacharide bng vic gii

phng polymer t isoprenoid lipid trc khi vn chuyn n trm cui cng. R rng, qu

trnh trn i hi phi c mt ngun nng lng v ta c th coi n tng t nh qu trnh

gii phng lipopolysaccharide ra khi nhng lp mng bn ngoi, y, cht cung cp

nng lng s l ATP.

Thit b

Xanthan l sn phm thng mi, c thc hin bng qu trnh ln men tnh truyn

thng trong nhng thit b ln men. Thit b c dng hnh tr ng v c lm bng thp


23

khng r. Thit b c b phn iu nhit nh lp v o v h thng ng dn xon t bn

trong thn tr. Ngoi ra bn trong cn c b phn sc kh, cnh khuy, cc h thng cm

bin o v iu chnh nhit , pH v lng oxy ha tan trong pha lng. Vic iu khin

bng cc thng s nhit , pH c thc hin bng cc chng trnh phn mm x l

thng tin t cm bin v cc bm iu khin.

Dung dch m phosphate hoc dung dch m khc nh NaOH, KOH c b sung vo

mi trng dinh dng duy tr pH n nh ca canh trng trong khong 7. Bnh ln

men c trang b h thng iu khin v trng, khuy, iu kin hiu kh, iu chnh nhit

, pH, bt, mc ha tan oxy.

Hnh 3.8. Thit b ln men dng xilanh


24

Thng s cng ngh:

Tc sc kh: 0,2 2 vvm, ti u: 0,5 1 vvm

Nhit ln men: 20 350C, ti u: 28 300C

Thi gian ln men: 96 h.

pH: 5,5 8, ti u: 6,4 7,4

Oxy ha tan: nng O2 ha tan 10 30% nng O2 bo ha nhit tng ng.

Tc khuy o: 200 500 rpm.

3.4. Thanh trng

Mc ch: chun b.

Sau giai on ln men, xanthan c thu nhn qua cc qu trnh xui dng. Canh

trng sau ln men phi c thanh trng nhm mc ch tiu dit ht cc t bo vi

khun Xanthomonas, chun b cho qu trnh tch vi sinh v v kt ta xanthan.

Cc bin i:

- Vt l: nhit canh trng tng, mt s thng s vt l nh t trng, nht,

thay i.

- Sinh hc: Vi khun Xanthomonas b c ch v tiu dit. Xanthomonas rt nhy cm

vi nhit v khng c kh nng sinh bo t nn ch cn thanh trng l . Tuy

nhin cn ch ti im nhit chuyn tip Tm c th ph hy chui polymer.

y Tm vo khong 1000C, tuy nhin n c th thay i theo chiu di ca chui

polymer cng nh t l lng cc gc pyruvate v acetate.


25

-

Thit b:Ta dng thit b thanh trng cu hnh mt ng lng trong mt ng.

Hnh 3.9. Thit b thanh trng ng lng ng

Thit b gm hai ng hnh tr ng trc c ng knh khc nhau v c t lng

vo nhau. Ngi ta lp t h thng trc c gn cc thanh khuy ti trc chung ca hai

ng hnh tr trn. Trong qu trnh hot ng, sn phm c bm vo ng hnh tr bn

trong, cn tc nhn nhit s i vo khong khng gian gia hai thn tr. Khi trc xoay,

cc thanh khuy hot ng s gip o trn u sn phm trong qu trnh gia nhit.

Thng s cng ngh:

- Nhit : 700C

- Thi gian: 30 pht.

3.5. Pha long

Mc ch: chun b cho qu trnh tch vi sinh vt

Cc bin i: t c cc bin i xy ra ngoi nht gim.


26

Thit b:

Thit b dng hnh tr c cnh khuy. S dng nc nng pha long.

Thng s cng ngh:

- T l pha long: ty vo nht cui cng ca canh trng ln men.

- Nhit nc pha long: 70-800C

- nht ca dch sau pha long: 100cP

3.6. Tch vi sinh vt

Mc ch: chun b cho qu trnh kt ta thu nhn xanthan.

Cc bin i:

- Sinh hc: canh trng thu c sau ln men gm: xanthan, t bo vi khun, c cht

st v cc hp cht cc. Qu trnh ly tm s tch hu ht cc t bo vi khun ra khi

canh trng ln men.

- Vt l: cc tnh cht vt l nh nht, nhit , canh trng thay i.

Thit b:

Trc khi a qua thit b ly tm, sn phm ln men cn c pha long vi nc

v trng gim nht ca mi trng, gip tng hiu sut tch t bo ra khi dung

dch sn phm.


27

Hnh 3.10. Thit b li tm

S dng thit b ly tm c chn xoay dng cn. Cu to thit b bao gm mt chn

xoay dng cn quay quanh mt trc thng ng. Tt c c t trong v c nh.

Nguyn liu i vo y ca chn xoay. Di tc dng ca lc ly tm, cc huyn ph m

y l cc t bo vi khun s di chuyn v thnh ca chn xoay v bm trn . Phn

dung dch c cha xanthan di chuyn ln pha trn v chy trn ra ngoi v. Khi b dy,

thit b c ngng hot ng, lp b c tch bng dao hay tho ra ngoi bng ca x

y ca chn xoay.

Thng s cng ngh:

- Gia tc li tm: 8000.g

- Nhit ca dch ban u: 70oC

3.7. Kt ta

Mc ch: Khai thc.

Sau qu trnh lc b ht vi khun ca canh trng sau ln men, xanthan c thu

nhn bng cch lm chm qu trnh ha tan v cho kt ta bng cch thm cc hp cht

hu c tan trong nc, c th l acetone, alcohol, dioxane, mui hoc acid, ty vo

trng hp c th. y nhm s dng ethanol v mui NaCl.

Cc bin i:

- Vt l: dch tr ln c khi qu trnh kt ta c tin hnh.

- Ha l: s kt ta ca cc phn t xanthan nh s hnh thnh lin kt ca cc cation

ca mui vi cc gc tch in m c trong canh trng. Ngoi ra cn qu trnh trch


28

ly cc cht mu, xc vi khun, mt s mui, khng tt cho sn phm vo dung dch

cn.

Thit b:

Hnh 3.11. Thit b kt ta

- Qu trnh kt ta c din ra trong cc bn cha c cnh khuy. Mui v ethanol

c b sung vo vi t l nht nh so vi nng xanthan v th tch ca dch thu

c sau ly tm. Cnh khuy hot ng sut qu trnh kt ta tng hiu kh nng

tip xc gia cc tc nhn gy kt ta vi xanthan kt ta xanthan thu c l ln

nht.

- Kt thc qu trnh kt ta, si polymer thu nhn c di dng rn m v phi c

ha tan v ra li bng nc hay dung dch KCl loi b ht nhng thnh phn gy

nh hng xu ti cht lng sn phm nh mnh vn t bo, microgel, vn hu c,

cc cht mu, ri lng v tch nc.

- Phn nc c tch sau khi thu nhn kt ta s c a qua qu trnh chng ct

thu hi ethanol, ti s dng cho nhng t sn xut sau.

Thng s cng ngh:

- Thi gian kt ta:

- m ca kt ta: 80%

- T l phi trn:

3.8. Tch nc

Mc ch: chun b cho qu trnh sy.

Xanthan gum sau khi kt ta c m t nht khong 80% v khi lng. Tuy

nhin, sy tht kh th rt kh khn v nhng nh hng khng mong mun ca dung

dch xanthan gum trong dung dch mui. Do , cn phi tch nc trong khi kt ta n

khong 50% m hoc t hn qu trnh sy pha sau c hiu qu hn.


29

Bin i: Bin i quan trng nht l huyn ph c tch lm hai pha ring bit, pha rn

l rn t xanthan, pha lng l dch cha cn, mui, Ngoi ra, cc thng s vt l ca

dch nh nht, nhit ,.. thay i tng i. Cn cc bin i v sinh hc cng nh ha

sinh hu nh khng c.

Thit b: s dng thit b ly tm a

Hnh 3.12. Thit b li tm a

Nguyn tc hot ng ca thit b: S dng thit b ly tm c chn xoay dng cn.

Cu to thit b bao gm mt chn xoay dng cn quay quanh mt trc thng ng. Tt

c c t trong v c nh. Nguyn liu i vo y ca chn xoay. Di tc dng ca

lc ly tm, cc huyn ph m y l cc kt ta rn m ca xanthan s di chuyn v

thnh ca chn xoay v bm trn . Phn dung dch gm cn, mui v cc hp cht

c trch ly trong qu trnh kt ta s di chuyn ln pha trn v chy trn ra ngoi v.

Khi b dy, thit b c ngng hot ng, lp b c tch bng dao hay tho ra ngoi

bng ca x y ca chn xoay.

Thng s cng ngh:

- Gia tc li tm:

- m ta rn: 30 50%


30

3.9. Sy

Mc ch: khai thc, hon thin v bo qun.

Cc bin i:

- Vt l: nhit s tng cao trong bn thnh phm.

- Ha hc: m gim, nhit cao c th phn hy mch polymer trong cu trc ca

xanthan.

- Ha l: bin i quan trng nht l s chuyn pha t lng sang hi ca nc.

- Sinh hc: cc vi sinh vt cn st li b c ch hoc tiu dit di tc dng nhit ca

qu trnh sy, hot ca nc gim.

Thit b: S dng thit b sy bc x hot ng lin tc dng ng hm (tunnel).

Cu to: Thit b c mt bng ti c lm bng thp khng r cha mu nguyn liu

cn sy. Pha trn bng ti b tr cc tm hay ng bc x.

Hnh 3.13. Thit b sy bc x

Nguyn tc hot ng: Nguyn liu s c np ln bng ti v di chuyn lin tc theo

chiu t tri sang phi. Di tc dng bc x nhit ca cc tia, nc chuyn pha thnh hi

v c tch ra khi nguyn liu. Cng tia v thi gian lu s quyt nh n m

cui ca sn phm.

Thng s cng ngh:

- Thi gian lu:

- Cng bc x:

- m cui ca sn phm: 8 15%


31

3.10. Nghin

Mc ch: hon thin

Sau khi sy kh, xanthan gum c nghin n kch thc ph hp nhm iu

khin mc phn tn v lm tng kh nng ha tan trong dung dch. ng thi to khi

sn phm d dng cho vn chuyn, lu tr v s dng.

Cc bin i:

- Vt l: kch thc ca nguyn liu s gim, din tch b mt ring s tng ln. Di

tc dng ca cc lc, nhit ca nguyn liu ca nguyn liu s tng ln.

- Ha l: sau khi nghin, tc ht m s tng ln, lm m ca sn phm tng, c

th dn ti tnh trng nguyn liu b vn cc.

Thit b: thit b nghin ba.

Cu to: thit b nghin ba bao gm mt rotor quay vi tc cao c gn vi mt vng

ai, trn vng ai c gn cc tay p (ba). Mt trong ca v bao c cu to c cu

to bng vt liu dai v cng. Ngoi ra cn trn v c th trang b sng gi li nhng

nguyn liu cha c nghin n mc t yu cu.

Hnh 3.14. Thit b nghin ba

Nguyn tc hot ng: Khi rotor quay, cc tay p s chuyn ng v u ca cc tay p

to thnh vng trn, khong cch gia vng trn ny vi v bao l rt nh ( ty thuc vo

kch thc ca nguyn liu v sn phm cui cng). Khi vn hnh, nguyn liu c tay

p a n khe hp gia u ba v thnh ca v. Di tc dng ca lc va p v lc ma

st, nguyn liu s v ra. Phn nguyn liu sau nghin nu t yu cu s qua tm sng

pha di i ra ngoi, cn nu cha t kch thc s c gi li v tip tc nghin n

khi t kch thc tiu chun.


32

Thng s cng ngh:

- Tc quay

- Kch thc khe hp

- Kch thc u ra ca sn phm.

3.11. ng gi

Mc ch: bo qun v hon thin. Sn phm xanthan l mt sn phm ht m mnh nn

cn bao gi chng trong cc bao b c kh nng chng ht m cao.

Cc bin i: sn phm t bin i trong qu trnh ny.

Thit b: qu trnh ng gi tin hnh trn dy chuyn t ng.

4. CH TIU CHT LNG CA SN PHM XANTHAN GUM

4.1. Ch tiu vt l

- Trng thi: dng bt mn, khng vn cc.

- Mu sc: mu kem

4.2. Ch tiu ha l

Theo QCVN 4 -21: 2011/BYT Quy chun k thut quc gia v ph gia thc phm

cht lm dy. Yu cu:

- nh tnh:

tan: tan trong nc, khng tan trong ethanol.

To gel: phi c phn ng to gel c trng.

- tinh khit:

Gim khi lng khi sy kh: khng c qu 15% (nhit sy 1050C trong

2.5 gi).

Tro ton phn: khng c qu 16% sau khi sy.

Acid pyruvic: khng c nh hn 1.5%

Nitrogen: khng c qu 1.5%

Ethanol v isopropanol: khng c qu 500mg/kg, dng n cht hoc hp

cht.

Ch: khng c qu 2 mg/kg.

4.3. Ch tiu vi sinh

Tng s vi sinh vt: khng c qu 5000 CFU/g.

E.Coli: m tnh i vi mu th.

Salmonella: m tnh i vi mu th.

Nm men v nm mc: khng c qu 500 CFU/g.


33

5. TI LIU THAM KHO

[1] Nout R.M.J. et al, Food Fermentation, Wagemngen aceademic publicshers, 2005

[2] Nguyn Ln Dng, Vi Sinh Vt Hc, NXB Gio Dc, 2003

[3] V.S.Wadhai and A.N.Dixit, Production of xanthan gum by xanthomonas

campestrisand comparative study of xanthomonas campestris isolates for the

selection of potential xanthan producer, 2011.

[4] Flores Candia J-L, Deckwer W-D. Xanthan gum. In: Flickinger MC, Drew

SW, editors. Encyclopedia of bioprocess technology: fermentation, biocatalysis,

and bioseparation, vol. 5. New York: Wiley, 1999. pp. 2695711.

[5] Rosalam S, England R. Review of xanthan gum production from unmodified

starches by Xanthomonas campestris sp. Enzym Microbial Technol. 2006.

[6] Souw P, Demain AL. Nutritional studies on xanthan production by Xanthomonas

campestris NRRL-B-1459. Appl Environ Microbiol. 1979;37:11861192.

[7] Druzian JI, Pagliarini AP. Xanthan gum production by fermentation from residue

of apple juice. Cincia e Tecnologia de Alimentos. 2007.

[8] Papagianni M, Psomas SK, Batsilas L, Paras SV, Kyriakidis DA,

Liakopouloukyriakides M. Xanthan production by Xanthomonas campestris in batch

cultures. Process Biochem. 2001.

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