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Trng i Hc M TPHCMKhoa : Cng Ngh Sinh Hc

Bi Bo CoMn: Cng Ngh Bo Qun Ch Bin Rau Qu

CC CHT X TRONGRAU QU

GV: Ths Nh Xun Thin Chn

Nhm: 2Hong Bi Yn 0953010921Nguyn Th Thanh Trc 0953010809Nguyn Th Thanh Tho 0953010647L Th Nguyt Thanh 0953010618Nguyn L Trang Ngc 0953010463

Mc Lc

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Danh mc bng

Bng 1 Bn cht cht x...............................................................................................5

Bng 2 Cc thc phm giu cht x v cc thc phm cha t cht x......................5

Bng 3 S phn chia cht x khng tan va tan c trong ng cc...........................8

Bng 4 S phn chia cht x khng tan va tan c trong ht Psyllinum..................9

Bng 5 S phn chia cht x khng tan va tan c trong tri cy ..........................10

Bng 6 S phn chia cht x khng tan va tan c trong cc loi u...................11

Bng 7 S phn chia cht x khng tan va tan c trong rau ci............................11

Bng 8 Cc ngun cung cp cht x h tan v khng ha tan...................................14

Bng 9 Nhu cu s dng cht x theo tui v gii tnh........................................16

Danh mc hnh

Hnh 1 Cht x khng ha tan c trong Bng ci xanh v Ng cc............................6

Hnh 2 Cht x ha tan c trong qu Cam v dng gel ca Pectin..............................7

Hnh 3 Cc loi ng cc................................................................................................8

Hnh 4 V ht m Psyllium......................................................................................9

Hnh 5 Cc loi tri cy.................................................................................................9

Hnh 6 Cc loi u.....................................................................................................10

Hnh 7 Cc loi rau ci................................................................................................11

Hnh 8 Ngun cung cp cht x.................................................................................15

Hnh 9 Cu to cellulose.............................................................................................17

Hnh 10 Cng thc cu to Cellulose.........................................................................17

Hnh 11 Si bng gn bng vi s da................................................................18

Hnh 12 cu trc cellulose thc vt............................................................................18

Hnh 13 O-acetyl-4-O-methylglucuronoxylan cy g cng...................................22

Hnh 14: Arabino-4-O-methylglucuronoxylan cy g mm ..................................23

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t Vn Trong nhng nm gn y, thi i cng nghip ngy cng pht trin dn n

nhiu sn phm thc phm hp, thc n nhanh ngy cng nhiu. iu gp phn

lm gia tng nhng cn bnh nguy him ca thi i: nhng bnh v chuyn ho nh bo

ph, tiu ng, p huyt cao, tim mch. Chnh v vy nhiu nh khoa hc v ang t

mi quan tm n vic cn iu chnh li li sng, bt u t vic xem li c cu ba n

hng ngy.

Theo iu tra nghin cu ca Vin Dinh Dng, thi quen n ung ca ngi Vit

Nam trong 20 nm gn y din bin theo chiu hng bt li cho sc kho. l

khuynh hng n nhiu tht, cht bo ng vt v qu t rau, qu, c. Trong khi Rau

qu l ngun thc phm cung cp nhng cht x, sinh t, khong cht bao gm c nhng

cht chng oxy ho quan trng. Nhng vi cht ny cn thit cho nhu cu chuyn ho,

cho h min dch, c tc dng gii c, bo v thnh mch mu v lm chm qu trnh

lo ho. Chnh v vy vic tm hiu nhng kin thc v cht x trong thc phm l cn

thit. T nhng hiu bit c th xy mt thc n b dng v hp l em li sc

khe tt.

Theo khuyn co ca t chc Y t quc t, mi ngi cn khong 400g rau qu

mi ngy. Tuy nhin hin nay, chng ta ch n trung bnh khong 200g, c ngi n cha

n 100g rau qu mi ngy. Do , iu thit yu nht trong vic ci thin c cu ba n

l nn tng cng lng rau, rau luc, nu soup, rau sng hoc rau trn. Cch xa cc

ba n nn n dm thm tri cy, chui, to, l, du ty. Cn n a dng nhiu loi rau

qu, c khc nhau cung cp cc nhm cht sinh t hoc khong cht cn thit.

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Chng I: Tng quan v cht x

I. Cht x (fiber)

Cht x l thnh phn quan trng trong khu phn n, gip cho h tiu ha lun

khe mnh, ng thi tham gia vo nhiu qu trnh chuyn ha khc nh: gip n nh

lng ng, cholesterol trong mu. Theo T chc Y t th gii, tm quan trng ca cht

x thc phm i vi sc khe con ngi c th so snh ngang bng vi vai tr ca

vitamin, cc nguyn t vi lng v khong cht. Cht x c xem nh cc tc nhn loi

b c t gy nn nhng bnh cht ngi nh: tim mch, tiu ng. Bn cnh cht

x cn gp phn tng cng sc khe cho mi ngi, c bit l nhng ngi cn gim

trng lng c th.

1. Khi nim

T fiber (bc M) cng c th c vit l fibre (Anh). N bt ngun t ting La

Tinh fibra, c ngha l si. Theo t in y khoa Medilexicon, thc n cha cht x

c ngha l cht dinh dng trong ba n m khng c tiu ha bi men d

dy rut.

Cht x c xem l thc n th. N l mt phn ca thc phm khng th

chuyn ho c bi h tiu ho ca con ngi hay l phn cn li sau qu trnh

tiu ho, c y i ngang qua h tiu ha v c hp thu nc khi di chuyn

qua ng rut.

Cht x (cn gi cellulose) l cht b thc n cn li sau khi c tiu ha, gm

cc cht to thnh vch t bo (cellulose, hemicellulose, pectin v lignin) v cc

cht d tr, bi tit bn trong t bo (gm, nhy). Ngoi ra hin nay cc cht sp,

cutin, glycoprotein (cht m cu to vch t bo khng tiu ha c) cng c

xp vo loi cht x thc phm.

Cht x c bn cht l cc lignin, xenlulo, hemixenlulo, pectin, cc cht keo, cc

cht nhy inlunin, oligosaccarit.

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Bng 1 Bn cht cht x

Trong thc vt c rt nhiu cht x. Cc sn phm sa, sn phm c ngun gc

ng vt nh tht, c, trng hu nh khng cha cht x. Cc sn phm cha

nhiu cht bo cha hm lng cht x rt t hay nhng sn phm cha nhiu cht

x hu nh khng cha cht bo.

Bng 2 Cc thc phm giu cht x v cc thc phm cha t cht x

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Cht x c tm thy trong v v thnh t bo thc vt nh: ht ng cc, rau,

qu, c Cht x khng phi l ngun cung cp nng lng, vitamin hay khong

cht.

2. Phn loi :

Thc n cha cht x thng c chia nh thnh phn ln l loi khng ha tan

v ha tan. C 2 loi cht x ny u hin din trong tt c cc thc n t thc vt v u

c ch cho sc khe v rt him khi t l bng nhau. Cc loi thc phm khc nhau th

cha cc loi cht x khc nhau.

V d: cm yn mch th cha ti 50% cht x tan c trong tng s cht x, cn

cm la m ch c 20% l cht x tan c.

a. Cht x khng ha tan

c im:

Cng v c dng si

Ch yu l cellulose, ngoi ra cn c hemicellulose v lignin.

Cht x khng ha tan c c tnh thm thu nc trong rut, trng ln to iu

kin cho cht b thi d thot ngoi.

Cht x khng ha tan trong nc nh: cm la m, ht ng cc cha xay, rau.

Hnh 1 Cht x khng ha tan c trong Bng ci xanh v Ng cc

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Vai tr:

Cht x khng ha tan c nhiu chc nng, bao gm di chuyn khi thng qua

ng tiu ha v kim sot pH trong ng tiu ha.

Li ch ca cht x khng ha tan:

Tng cng chuyn ng bnh thng ca rut v ngn nga to bn.

Gia tng s thi tr cht c qua rut kt.

Bng cch gi mt pH ti u trong ng rut, cht x khng ha tan gip ngn

nga vi khun to ra cht c th dn n ung th ng rut. Cht x khng ha

tan i qua ng tiu ha m khng thay i hnh dng ca n.

b. Cht x ha tan

c im:

Gm pectin cng vi cht dch nhy, pentozan...

Pectin c trong ci trng bi, cam, qut v mt s loi qu khc, d tan trong

nc, khi gp ng v axit th to thnh th ng (gel).

Hnh 2 Cht x ha tan c trong qu Cam v dng gel ca Pectin

Vai tr:

Loi cht x ny c th lm gim cholesterol v gip c th iu ha ng trong

mu

Cht x tan c kt hp vi acid bo, lm chm thi gian lm rng d dy v lm

gim lng ng c hp thu vo c th

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Cht x ha tan khi i qua rut s to ra th ng lm chm qu trnh hp thu mt

s cht dinh dng vo mu v cng lm tng xp, mm ca b thi tiu ha.

Li ch ca cht x tan c:

Lm gim lng cholesterol, c bit l LDL (cholesterol xu)

iu ha lng ng thu vo, iu ny c bit c ngha i vi ngi b tiu

ng v hi chng chuyn ha.

Khng c cht x no c th tiu ha c c. tuy nhin, cht x tan c thay

i khi n i ngang ng rut, ni n ln men bi vi khun. X tan c hp thu

nc v tr thnh th cht gel st.

c. S phn chia gia cht x khng ha tan v ha tan trong thc phm

Ng cc

Hnh 3 Cc loi ng cc

Tan c Khng tan cLa mch 1g 4gYn mch 1g 2g

Bt yn mch 1g 3gBng 3 S phn chia cht x khng tan va tan c trong ng cc

(1/2 tch c ch bin)

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Ht

Hnh 4 V ht m Psyllium

Tan c Khng tan cHt Psyllium 5g 6g

Bng 4 S phn chia cht x khng tan va tan c trong ht Psyllinum

Tri cy

Hnh 5 Cc loi tri cy

Tan c Khng tan cTo 1g 4g

Chui 1g 3gDu (1/2 tch) 1g 4g

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Cy h cam chanh

(cam, bi chm)

2g 2-3g

Xun o 1g 2go 1g 2gL 2g 4g

Mn 1g 4gMn (1/4 tch) 1g 3g

Bng 5 S phn chia cht x khng tan va tan c trong tri cy

Cy h u

Hnh 6 Cc loi u

Tan c Khng tan cu en 2g 5.5gu thn 3g 6gu Lima 3.5g 6.5gu Navy 2g 6g

u pha bc 1.5g 5.5gu rng 2g 7g

u lng (vng, xanh l, 1g 8g

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cam)u H Lan 1g 6gu mt en 1g 5.5g

Bng 6 S phn chia cht x khng tan va tan c trong cc loi u

Rau ci

Hnh 7 Cc loi rau ci

Tan c Khng tan cBng ci xanh 1g 1.5gCi bruxen 3g 4.5gC rt 1g 2.5g

Bng 7 S phn chia cht x khng tan va tan c trong rau ci

Nhn xt:

Cc cht x ha tan v khng ha tan tn ti trong rau qu vi t l khc nhau v

thng khng bng nhau.

Cc cht x khng ha tan thng chim nhiu hn cht x ha tan trong rau qu

3. Tnh cht chung ca cht x

L cht bn vi nhit, n nh khi ch bin nhit cao.

Bn vng trong mi trng axit, ng dng b sung trong nc p hoa qu.

n nh sau thi gian tng tr.

Khng lm thay i trng thi, mu sc, mi v khi c b sung vo cc sn

phm.

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4. Tc dng ca cht x

Cht x gip ng tiu ha, lm mm cht thi rn, gip o thi cc cht thi

rn ra ngoi qua ng tiu ha.

Cht x l ngun nhin liu quan trng cho cc vi khun c li ang sng trong

ng tiu ha. Cc vi khun c li ny gip tit ra cc cht dinh dng khc

c th hp th v ngn nga cc vi khun c hi sinh si ny n trong ng tiu

ha.

Cht x thc s c th kt ni vi cc cht c nguy c c hi trong ng tiu ha

v o thi chng ra ngoi.

Chng to bn: cht x vo c th c tc dng thm thu nc, n to ra lm tng

khi lng b thi. Mt khc, n kch thch nhu ng rut non, rut gi co bp

mnh lm cho tiu ha d hn v d tng phn ra ngoi. Ngoi ra, cht x rut

gi c tc dng tng kh nng ln men ca vi khun rut gi vi cc

polysaccharide, sinh ra cc acid chui ngn l ngun nng lng cho t bo nim

rut gi.

iu tr bnh i tho ng: mc ch ca vic iu tr bnh i tho ng l

gi hm lng ng glucose trong mu ca mc bnh thng v ngn nga cc

bin chng. Thc phm giu cht x lm chm li qu trnh hp thu ng vo

mu, qua gi cho mc ng trong mu khng b tng t ngt ngay sau ba

n, m tiu ha hp thu t t.

Cht x vi bnh tim mch: Cht x lm gim cholesterol bng cch lm gim

cholesterol c hi (LDL) v tng cholesterol c ch (HDL). Nu ch n nhiu

b, cholesterol tng cao, nhng khi thm cht x vo khu phn th lng

cholesterol gim xung ti 20%. Cholesterol tng cao trong mu l nguyn nhn

gy mt s bnh tim mch.

Phng nga ung th: nhiu nghin cu cho thy, nhng ngi dng nhiu cht x

t c nguy c b ung th ng tiu ha. Ung th kt trng thng xy ra phn

cui ng tiu ha, v y l ni to ra mt s cht c hi cho t bo nh amoniac,

indol, phenol, amin. Cht x ha tan d dng ln men trong rut to mt mi

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trng c tnh kh cao, c kh nng c ch qu trnh oxy ha v gip nui dng

h vi khun c ch sng ti rut. H vi khun ny to ra cc axit bo d bay hi,

tc ng trc tip ln t bo thnh rut kch thch s phn chia ca t bo bnh

thng, c ch s pht trin ca t bo ung th. Cn cht x khng ha tan tuy t

c kh nng ln men nhng li ng vai tr tch cc trong vic bi xut cc cht

c kh nng gy ung th trc khi chng c thi gian gy hi thnh rut.

Chng bo ph: ch n giu cht x tuy lm gim calo ca khu phn, nhng

vn m bo cm gic no, rt c li cho nhng ai mun gim trng lng c th.

Mt khc, cht x trong qu trnh tiu ha s ht nc n ra, lm cho cc cht

dinh dng thm qua lp nhy nht dn qua thnh rut vo mu.

iu tr si mt: Khi kt hp vi acid mt, cc cht x t nhin ngn chn nguy c

to ra si mt.

Gim m mu: Khi cc cht x khng ha tan ht nc, chng gi lun mt phn

mui mt nn kch thch c th tng cng sn xut mui mt b vo lng

thiu ht, v th m tng s dng cholesterol.

5. Ngun cung cp cht x

Theo bng thnh phn dinh dng thc phm Vit Nam ca vin dinh dng 2000, thc

n cha nhiu cht x cellulose c sp xp theo th t t nhiu n t nh sau:

Nhm ng cc: cm go m, bnh m en, khoai m, khoai lang, u xanh, u

a, u rng, u en, u nnh, ht u c ve, m en.

Nhm rau: mng kh, nm mo, rau cu, mng tre, rau m, bp chui, u xanh,

ci soong, xng rng, b ngt, rau dn, rau lang, ci trng, cn ta, rau nung.

Nhm tri cy: chui kh, v sa, thanh long, su ring, cam, ci da, mt di,

nhn, nho kh.

Phn loi Ngun cung cp

Cht x ho tan - Rau h u- u , u tng v cc loi u khc

- Cc loi yn mch, kiu mch, la mch

- Cc loi tri cy, c bit l to, chui, h u

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- Cc loi rau xanh nh bng ci xanh, carot

- Cc loi rau c nh khoai ty, khoai m v hnh- v ca

nhng rau xanh ny cung cp cht x khng tan

- V ht m - cht x ho tan dng nhy

Cht x khng

ho tan

- Cc thc phm nguyn ht

- Cm ca cc loi ng cc

- Cc loi qu hch v cc loi ht

- Cc loi rau xanh nh sp l, u xanh, cn ty

- Cc loi v tri cy bao gm c c chuaBng 8 Cc ngun cung cp cht x h tan v khng ha tan

Nhn chung:

Cc loi rau qu c cha nhiu cht x.

Thc phm c ngun gc ng vt nh sa, tht, c, trngkhng c cht x.

Cht bo c rt t cht x, cc loi thc phm c giu cht x th thng ngho

cht bo.

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Hnh 8 Ngun cung cp cht x

6. Nhu cu khuyn ngh

Nhu cu cht x tu thuc vo tui tc, gii tnh, thi quen n ung ca tng quc

gia.

Chu u l 21-25,3g/ngy. M xp x 35g/ ngy, an Mch, Thu s c mc

25-30g ngy.

T chc Y t Th gii khuyn co nn dng 20-30g cht x mi ngy. Mi ngy

mt ngi kho mnh bnh thng nn dng 25-30g cht x, c ngha chng ta

cn 12g cht x cho 1000kcalo nng lng, nhng hu nh chng ta ch cung cp

cho c th khong 10g.

Tr em c nhu cu cht x tu thuc la tui. c thng thng l 10g v mi

tui tng thm 1g.

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tui g cht x/ngy tui g cht x/ngyTr em Ph n mang thai

1-3 19 Nh hn 18 284-8 25 Trn 18 28

n ng Ph n9-13 31 9-13 2614-18 38 14-18 2619-50 38 19-50 25Trn 51 30 Trn 51 21

Bng 9 Nhu cu s dng cht x theo tui v gii tnh

7. Mt s lu khi s dng cht x

Khi c th dung np qu nhiu v qu nhanh cht x s dn n y bng, kh

tiu v thiu nc bi vy khi s dng cht x cng phi t t, ng liu lng.

Dng nhiu thc n cha cht x khng gy nguy him g ngoi cm gic t nhin

l no y v i khi si bng. Nhng nu dng cht x di dng bt kh tinh ch

th c th gy tc dng ph. Ngi c c a d ng ht phi bt kh ca cht x

chit tinh c th b d ng.

C th d dng phng trnh iu ny bng cch khng dng cht x dng bt v

ung nhiu nc sau khi dng cht x.

II. Cellulose

1. Tnh cht vt l

Cellulose hin din dng rn, mu trng, khng mi, khng v, khng tan trong

nc, k c nc nng. Cellulose cng khng b ha tan trong cc dung mi hu

c thng thng nh benzen, ru, ete, axeton (aceton),

Cellulose c nhiu vch t bo thc vt, c nhiu trong bng vi, bng gn (95-

98%), ay, gai, tre, na, v da, Trong g, cellulose chim khong 40-50%

2. Cu to ca cellulose

Cellulose l mt loi polysaccarit (gluxit phc tp) do cc monosaccarit (gluxit

n gin) l cc beta-glucozit lin kt vi nhau bng lin kt beta-1.4-glicozit (hay

glucozit) m thnh.

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Hnh 9 Cu to cellulose

Cng thc dng cng thc phn t ca Cellulose l (C6H10O5)n. Do mi mt xch

ca cellulose c cha 3 nhm OH nn cellulose cn c vit l (C6H7O2(OH)3)n

Khi lng phn t Cellulose rt ln, khong 1 000 000 2 400 000 vC.

Cng thc cu to ca Cellulose do cc bate-glucoside lin kt vi nhau bng lin

kt beta-1,4-glicoside (hay beta-1,4-glucoside, beta-1,4-glicoside, beta-1,4-

glycoside, beta-1,4-glucoside).

Do cellulose c mch thng v Cellulose thng gp c dng si. Si bng

gn, bng vi hay si x da m ta thy l s xon hay chp vo nhau ca v s

cc i phn t Cellulose chung quanh mt trc chung.

Hnh 10 Cng thc cu to Cellulose

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Hnh 11 Si bng gn bng vi s da

Hnh 12 cu trc cellulose thc vt

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Tnh cht ha hc

Cellulose b ha tan trong nc Schweitzer (dung dch phc cht (Cu(NH3)4)2+ c

mu xanh bic, xanh dng m, do dung dch NH3 ha tan Cu(OH)2 to thnh

dung dch nht.

Cellulose c to ra do cy xanh quang hp vi s hin din ca dip lc t

(chlorophyll).

Cellulose b thy phn n cng to glucose vi s hin din cc men (enzyme)

thch hp hay axit v c (H+) lm xc tc. Trong c th con ngi khng c men

thy phn c Cellulose nhng loi ng vt nhai li (tru, b,..) c men

cellulosase nn thy phn cenllulose tao glucose. Do con ngi khng tiu ha

c cenllulose nhng loi ng vt n c tiu ha c.

Cellulose tc dng vi dung dch HNO3 m c, c dung dch H2SO4 m c

lm xc tc, un nng, c th thu c cellulose mononitrat, cellulose initrat,

cellulose trinitrat, do mt, hai hay ba nhm OH trong mi n v mt xch ca

cellulose tham gia phn ng to thnh nhm este v c nitrat (-ONO2).

Cellulose trinitrat dng lm thuc sng khng khi (pyrocellulose, guncotton), lu

n, mn.

Cellulose tc dng vi anhidrit axetic, c H2SO4 lm xc tc, to cellulose

monoaxetat, cellulose diaxetat v cellulose triaxetat, ty theo mt hai hay ba nhm

OH trong mi n v mt xch ca cellulose tham gia phn ng to nhm chc

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este (-OCOCH3). Hn hp cellulose diaxetat v cellulose triaxetat c dng lm

t si axetat cng nh phim nh

3. Vai tr

T cellulose cng iu ch c cc loi t si nhn to visco, t ng-amoniac

(ha tan cellulose trong nc Schweitzer, to dung dch nht, ri p dung dch

nht ny qua nhng l nh to si t ng-amoniac)

Cellulose trong bng, ay, gai, v tri da, tre, g,... c dng lm vi (cotton),

bn dy thng, lm giy vit, vt liu xy dng, lm bn gh ( g) cellulose

cn c dng iu ch ru etylic (thy phn to glucose, ri cho ln men ru).

III. Hemicellulose

1. c tnh ca hemicellulose

Hemicellulose l mt loi polymer phc tp v phn nhnh, trng hp khong

70 n 200 n phn.

Hemicellulose cha c ng 6 carbon gm glucose, mannose v galactose v

ng 5 gm xylose v arabinose. Thnh phn c bn ca hemicellulose l D

xylopyranose, lin kt vi nhau bng lin kt -(14).

bn ha hc v bn nhit ca hemicellulose thp hn so vi cellulose v chng

c kt tinh v trng hp thp hn ( trng hp

n gin : c th c tch ra di tc dng ca cc ha cht dng trong qu

trnh nu g.

Phc tp: loi ny lin kt kh cht ch vi lignin v do vy cn c nhng phn

ng ha tan lignin kh mnh. Hemicellulose rt i nc, s c mt ca n

trong bt lm cho bt d nghin hn.

Cellulosesen : l nhng hexose v pentose lin kt kh cht ch vi cellulose

3. Cu to

Cu to ca hemicellulose kh phc tp v a dng ty vo nguyn liu, tuy nhin

c mt vi im chung gm:

- Mch chnh ca hemicellulose c cu to t lin kt -(14).

- Xylose l thnh phn quan trng nht.

- Nhm th ph bin nht l nhm acetyl O lin kt vi v tr 2 hoc 3.

- Mch nhnh cu to t cc nhm n gin, thng thng l disaccharide hoc

trisaccharide. S lin kt ca hemicellulose vi cc polysaccharide khc v vi

lignin l nh cc mch nhnh ny. Cng v hemicellulose c mch nhnh nn

tn ti dng v nh hnh v v th d b thy phn.

Hemicellulose l polysaccharide trong mng t bo tan trong dung dch kim v c

lin kt cht ch vi cellulose, l mt trong ba sinh khi t nhin chnh. Cng vi

cellulose v lignin, hemicellulose to nn thnh t bo vng chc thc vt. V

cu trc, hemicellulose c thnh phn chnh l D-glucose, D-galactose, D-

mannose, D-xylose v L-arabinose lin kt vi cc thnh phn khc v nm trong

lin kt glycoside. Hemicellulose cn cha c axit 4-O-methylglucuronic, axit D-

galacturonic v axit glucuronic. Trong , ng D-xylose, L-arabinose, D-

glucose v D-galactose l ph bin thc vt thn c v ng cc. Tuy nhin, khc

vi hemicellulose thn g, hemicellulose thc vt thn c li c lng ln cc

dng lin kt v phn nhnh ph thuc vo cc loi v tng loi m trong cng

mt loi cng nh ph thuc vo tui ca m .

Ty theo trong thnh phn ca hemicellulose c cha monosaccharide no m n

s c nhng tn tng ng nh manan, galactan, glucan v xylan. Cc

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polysaccharide nh manan, galactan, glucan hay xylan u l cc cht ph bin

trong thc vt, ch yu cc thnh phn ca mng t bo ca cc c quan khc

nhau nh g, rm r, v.v

Trong cc loi hemicellulose, xylan l mt polymer chnh ca thnh t bo thc

vt trong cc gc D-xylopyranose kt hp vi nhau qua lin kt -1,4-D-

xylopyranose, l ngun nng lng di do th hai trn tri t. a s phn t

xylan cha nhiu nhm trc chnh v chui bn. Cc gc thay th ch yu trn

khung chnh ca xylan l cc gc acetyl, arabinosyl v glucuronosyl. Cc nhm

ny c c tnh lin kt tng tc cng ha tr v khng ha tr vi lignin,

cellulose v cc polymer khc.

Cu to, s lng v v tr ca xylan cc loi thc vt khc nhau l khc nhau.

Xylan tn ti dng O-acetyl-4-O-methylglucuronoxylan cy g cng, hay

arabino-4-O-methylglucuronoxylan cy g mm, hay thnh phn cu to xylan

l axit D-glucuronic, c hoc khng c ete 4-O-methyl v arabinose cc loi ng

cc.

Hnh 13 O-acetyl-4-O-methylglucuronoxylan cy g cng

23

Hnh 14: Arabino-4-O-methylglucuronoxylan cy g mm

IV. Pectin.

1. c tnh ca pectin

Pectin l mt polysaccharide tn ti ph bin trong thc vt, l thnh phn tham

gia xy dng cu trc t bo thc vt. Pectin tn ti trong v gia cc thnh t bo.

L 1 cht khng c mi v

Di tc dng ca acid, enzyme protopectinaza hoc khi gia nhit th protopectin

chuyn thnh pectin. Pectin tr thnh dng gel (to ng) khi thm ng v acid.

y l c s sn xut mt.

Kh nng to ng ph thuc: ngun gc thu nhn, phn t lng ca pectin v

mc metoxyl ha.

2. c im ca pectin

Pectin l hp cht cao phn t polygalactoronic c n phn t l galactoronic v

ru metylic. Trng lng phn t t 20.000 - 200.000 vC. Hm lng pectin

1% trong dung dch c nht cao, nu b sung 60 % ng v iu chnh pH

mi trng t 3,1-3,4 sn phm s to ng.

24

Pectin c tnh keo, nht v bn ko ln, gy kh cho qu trnh lc, lm

trong, c c.

C kh nng b kt ta bi cn

3. Phn loi pectin

thc vt pectin tn ti ch yu 2 dng l pectin ha tan v protopectin khng

ha tan.

Pectin ha tan: acid pectic, acid poligalacturonic

Pectin khng ha tan: protopectin

4. Cu to

Cu to phn t pectin l mt dn sut ca acid pectic, acid pectic l mt polymer

ca acid D-galacturonic lin kt vi nhau bng lin kt 1-4-glycozide.

Dng protopectin khng tan, tn ti ch yu thnh t bo di dng kt hp vi

polysaccharide araban.

Dng ha tan ca pectin, tn ti ch yu dch t bo.

Cc cht pectin l cc polysaccharide, mch thng, cu to t s lin kt gia cc

mch ca phn t acid D- galacturonic C6 H10O7, lin kt vi nhau bng lin kt

1,4- glucoside. Trong mt s gc acid c cha nhm methoxyl (-OCH3). Chiu

di ca chui acid polygalacturonic c th bin i t vi n v ti hng trm n

v acid polygalacturonic.

25

Phn t lng: ca cc loi pectin tch t cc ngun qu khc nhau thay i trong

gii hn rng ty theo s phn t acid galaturonic v thng thay i trong phm

vi t 10.000 100.000. Trong cc hp cht dng glucid so v chiu di phn t th

pectin cao hn tinh bt nhng thp hn cellulose. V d t ngun to, mn thu

c pectin c phn t lng t 25.000 35.000, trong khi pectin ly t cam

li c phn t lng t ti 50.000.

Trong thc tin th tn pectin dng ch c acid pectinic v pectin.

5. Ch s pectin

Hp cht pectin c c trng bi 2 ch s quan trng l ch s methoxyl MI

biu hin cho phn trm khi lng nhm methoxyl OCH3 c trong phn t

pectin v ch s este ha DE th hin mc este ha ca cc phn t acid

galactoronic trong phn t pectin.

Da trn mc methoxy ha v este ha, trong thng mi chia pectin thnh 2

loi: pectin c methoxyl ha cao v pectin c methoxyl ha thp.

Pectin methoxyl ha cao (High Methoxyl Pectin HMP): DE >50 % hay MI >

7%. Cht ny c th lm tng nht cho sn phm. Mun to ng cn phi c

iu kin pH = 3,1 3,4 v nng ng trn 60 %.

Pectin methoxyl ha thp (Low Methoxyl Pectin LMP): DE < 50 % hay MI <

7%. c sn xut bng cch gim nhm methoxyl trong phn t pectin. Pectin

methoxy thp c th to ng trong mi trng khng c ng. Chng thng

c dng lm mng bao bc cc sn phm.

26

http://www.hoahocngaynay.com/images/stories/MOFs/Hoa_hoc/pectin_methoxy.png

Trong qu trnh bo qun c th b tch nc hoc lo ha. Qu trnh to ng ph

thuc vo nhiu yu t: ngun pectin, mc methoxy ha cng cao th kh nng

to ng cng cao. Khi s dng cn phi ha tan pectin vo nc, khi pectin ht

nc th mi s dng cng on cui ch bin.

Cc pectin u l nhng cht keo ho nc nn c kh nng hydrat ha cao nh s

gn cc phn t nc vo nhm hydroxyl ca chui polymethyl galacturonic.

Ngoi ra, trong phn t pectin c mang in tch m nn chng c kh nng y

ln nhau c kh nng lm gin mch v lm tng nht ca dung dch. Khi lm

gim tch in v hydrat ha s lm cho si pectin xch li gn nhau v tng

tc vi nhau to nn mt mng li ba chiu rn cha pha lng bn trong.

27

http://www.hoahocngaynay.com/images/stories/MOFs/Hoa_hoc/pectin_methoxy1.png

Chng 2 Vai tr ca cc cht x c hot tnh sinh hc I. pectin

Pectin l cht to gel quan trng nht c s dng to ra cu trc gel cho thc

phm. Kh nng to gel ca n c s dng trong nhng thc phm cn c s n nh

ca nhiu pha. Tc dng to gel ca pectin c s dng ch yu trong cc sn phm

mt tri cy v mt ng.

Tc dng ca pectin l to ra cu trc mt ng v mt tri cy khng b thay i

trong qu trnh vn chuyn, to ra mi v thm ngon cho sn phm v gim s ph v cu

trc. Trong mt s trng hp, pectin cn c s dng vi carageenan tng hiu qu

to gel.

1. Trong cng ngh thc phm

a. ng dng ca pectin trong cng ngh ch bin rau qu

Pectin l cht to ng tt nht c s dng to ra cu trc gel cho thc

phm, ch yu l nhng thc phm c ngun gc t rau qu. N c kh nng gi

mi t nhin trong ko ng hay cc sn phm khc, khng gy mi v l.

Tc dng to c ca pectin c s dng ch yu nhng loi thc phm m

qui nh khng cho php s dng nhng loi gum c gi thnh r hn hay

nhng loi thc phm cn c mt hnh dng tht t nhin.

28

HMP dng trong mt tri cy v mt ng:

- Vai tr ca pectin l nhm to ra mt cu trc cho mt ng v mt tri cy nhng

sn phm ny khi c vn chuyn vn khng thay i cu trc, to ra mi v thm ngon

cho sn phm, v gim ti a s phn r. Qu trnh sn xut mt ng v mt tri cy

phi m bo to ra s phn b ng u ca cc phn t trong pha lin tc ngay t khi

qu trnh khuy trn ngng li. Hm lng pectin s dng trong mt v mt ng

thng trong khong 0,2 0,4%.

- Pectin c kh nng to gel nhanh c gi tr c bit trong sn xut mt v yu cu ca

sn phm phi to c gel, to c trc khi ng hp.

- Qu trnh to gel ca pectin c th c to ra trong mt qui trnh lnh bng 2 cch:

+ Trn syrup ng pectin c hm lng cht kh ho tan t 60 65%, pH bng

3,8 4,2 vi dch acid tri cy t c pH = 3.

+ Trn dung dch pectin c pH = 2,9 v hm lng ho tan l 25% vi syrup

ng thu c hn hp mi c hm lng cht kh 23%.

LMP thng c ng dng trong mt tri cy c hm lng cht kh tan < 55%

-Loi LMP c chn da trn hm lng cht kh v pH trong sn phm. Trong nhng

sn phm c hm lng cht kh rt thp, v d nh mt tri cy khng ng cho ngi

b bnh tiu ng, LMP kh to lin kt vi nc, trong mt s trng hp ngi ta

c th s dng c pectin v carragenan.

b. ng dng ca pectin trong cng nghip bnh ko

29

Pectin tng tnh hp dn, to cu trc n hi, tng mi v tri cy t nhin v to b mt

bng lng cho sn phm. Pectin l cht to gel tt, tan nhanh, n nh. V vy, pectin

c ng dng nhiu trong cng nghip bnh ko nh: mt qu, ko do, lp mt bnh

kem, bnh ngt nhn hoa qu....

c. ng dng ca pectin trong cng nghip ch bin sa

30

Pectin b sung hng v tri cy cho cc sn phm sa chua. Cho pectin vo sa

ln men vi liu lng va , trn u c dung dch ng nht. Trong yaourt tri

cy, pectin to cu trc mn, gip phn b u cc mu tri cy nh trong sa v n cn

lm cho sn phm c b mt nhn bng. Trong cc sn phm nhiu lp, pectin cn c tc

dng n nh v gi cho tri cy khng b tch khi yaourt. Trong yaourt ung, pectin t

bi bo v protein khng b bin tnh trong qu trnh tit trng, ngn chn protein kt

ta v s kt ng, gip sn phm n nh v t tnh cht cm quan tt nht, khng gim

cht lng ngay c khi bo qun mt thi gian di, nhm ci thin cu trc yaourt, to kt

ta dng mn v lm tng gi tr cm quan thc phm trong sa chua.

d. ng dng ca pectin trong cng nghip ch bin nc gii kht

Vic s dng pectin trong cc sn phm ung rt ph hp v chng c

cacbonhydrate t nhin nng lng thp v n nh tnh c ca sn phm.

e. Cc ng dng khc ca pectin trong cng ngh thc phm

- Dng pectin hay pectat ch to bao b (mng) n c: mng thu c bng

cch em nhng sn phm vo dung dch pectin methoxyl thp hay natri pectat v sau

31

nhng vo dung dch canxi clorua. i khi ngi ta thm glyxerin vo dung dch pectin

lm do ho. Mng ph ln phi em sy.

- Pectin cn c s dng nhiu trong sn xut thc n king cho nhng ngi

mc bnh tiu ng. Loi thc n ny thng c hm lng ng rt thp.

2. Trong cng ngh dc phm

Pectin c dng ch bin thuc ung, thuc tim cm mu trc v sau

phu thut rng hm mt, tai mi hng, ph khoa. cha chy mu ng tiu ho,

tit niu. Dung dch pectin 5% cn c s dng nh thuc st trng H2O2 (nc

oxy gi) trong phu thut rng hm mt, tai mi hng (khng gy xt li cm mu

tt). Thm bng nht vo ch rng cm mu. Trn th trng hin c dc

phm Hacmophobin (c) v Arhemapctin (Php).

Tc dng dc l ca pectin

Pectin l mt loi cht x ho tan trong nc. N khng cung cp nng lng nhng c

nhiu gi tr phng, cha bnh nh:

- Ko di thi gian tiu ho thc n trong rut, c tc dng tng hp thu dng cht

trong thc n. Gim bo (do to cm gic no bng ko di, gim nng lng n

vo, do gip gim cn ngi bo ph).

- Gim hp thu lipid.

- Gim cholesterol ton phn trong mu.

- Khng ch tng ng huyt trc v sau ba n ngi c bnh tiu ng.

- Chng to bn.

- Cm mu.

- St trng.

- Hoa qu c nhiu pectin gip c th hp thu tt cc acid hu c v l cht trung

gian thc y s chuyn ho, tng kh nng s dng cc cht dinh dng trong

thc n.

Ngoi ra, qu trnh ln men cc cht pectin c ng dng rng ri trong k ngh

lm si ay, gai, dt vi, lm bao ti.

II. Oligosaccharide

32

Trong sa m, glucid c cu to phn ln l oligosaccharides (cht x tan) c

th gip b chng tiu chy, nhim trng h hp v tai gia. Oligosaccharides

trong sa m c tc dng c ch kh nng gy bnh ca Campylobacter Jejuni,

Vibrio cholera, Escherichia coli gy bnh ng rut v Streptococcus pneumonia

trong thc nghim v trong ng nghim. ng vai tr l pre-biotic

Fructo oligo sacharides (FOSs): Fructo sacharides l mt loi glucid khng tiu

ha, ln men mt cch t nhin trong thc phm nh hnh, chui, c chua, ti v

la m... FOSs c th sn xut cng nghip v b sung vo nhiu sn phm thc

phm v cc sn phm dinh dng. FOSs c tc dng gim cholesterol ton phn,

c bit l triglycerid. Mt s th nghim lm sng cho thy b sung thm 9-20g

FOSs/ngy c th gim cholesterol ton phn v triglycerid ti 27%.

III. Agar

ng dng trong thc phm: to gel bn nhit, c kh nng nh ha v lm bn, to

mng c bn c hc cao v trong sut

Dng lm thch, thay th pectin trong mt qu, thay gelatin trong cc sn phm

tht c, dng lm mi trng nui cy VSV

c s dng cng gum trogacanth hay gelatin trong trng ming ng lnh

(lm t nc qu, ng, sa), sn phm kem

IV. Cc hp cht gum

Xanthan gum

Dn xut ca cellulose cha lin kt 1,4 ca beta glucopyranose

Kh nng lm bn nh tng v n nh kh nng l lng cc ht nh

Bn nhit cao nn c ng dng nhiu trong sn phm hp

Ngoi ra cn ng dng trong sn xut bnh pudding n lin

Chng 3: nh hng ca cc hp cht x n cng nghI. Cellulose

33

- Cellulose c cu to mch thng, gm nhiu phn t glucose. Cellulose trong qu l

0,5 2,7%, c khi chim ti 6%; rau 0,5 2,8%. Cellulose t b bin i trong qu trnh

bo qun.

Cellulose c tc dng bo qun nng sn v mt c hc

- Tuy nhin cellulose gy nhiu kh khn trong qu trnh ch bin. Cellulose khng tan trong nc mc d nhit cao

Cellulose khng b phn hy nhng nt ra tr nn mm hn, cho php dch tiu

ha tip xc vi cc thnh phn dinh dng trong t bo thc vt

Cellulose lm cn tr s truyn nhit trong qu trnh ch bin.

II. Hemicellulose

- Trong rau qu, phn t hemicellulose gm cellulose v pentozan do vy n va l vt liu cu trc v t bo va l nguyn liu d tr nng lng cho cc qu trnh trao i

cht.

Hm lng hemicellulose trong rau: 0,3 3,1%; trong qu: 0,3 2,7% .

- Khi un nng vi s c mt ca acid clohydride:Hemicellulose pentozan cc ng galactose, manose, arabinose.

Khi s lm mm cu trc t bo, gim kh nng t v ca nng sn.

- Phn ln hemixenllulose khng tan trong nc tr mt s pentozan.Hemicellulose ha tan trong dung dch kim. Khi thy phn hemicellulose thu c

cc hexose nh mannose, galactose,.. cc pentose nh: arabinose, xylose

III. Pectin

- Pectin l glucid cao phn t nhng phn t lng ca n thp hn nhiu so vi cellulose v hemicellulose.

Cc cht pectin ng vai tr quan trng trong qu trnh trao i nc khi chuyn

ho cc cht v trong qu trnh chn ca rau qu.

34

Pectin c nhiu trong c qu v thn cy. Trong v qu cha 1,0 1,5%. Trong ht

lng pectin thng t hn.

- Pectin tn ti 2 dng: pectin ho tan v protopectin.

Trong qu trnh chn hoc un nng th protopectin pectin ho tan. Qu trnh

ny lm cho rau qu b mm dn.

S tm tt s thay i ca protopectin v pectin trong qu trnh bo qun

Trong qu trnh chn, di tc dng ca enzyme pectinase hoc s tham gia ca

cc acid hu c, protopectin b thy phn thnh pectin to cng lc lin kt gia cc

t bo gim.

- Pectin gy nh hng n qu trnh lc v c c Pectin b ph hu nhit cao trong thi gian di lm gim tnh ng ca sn

phm khi c c

35

Pectin tan trong nc to thnh dung dch c tnh keo cao. Keo pectin c nht

v bn rt ln nn gy kh khn trong qu trnh lm trong nc qu khi c c

nc qu.

Pectin c tnh keo, nht v bn keo ln, gy kh cho qu trnh lc, lm

trong, c c

S c mt ca pectin v ng lm cho qu khi nghin c tnh keo ha nn khi p

dch qu kh thot ra

Pectin to keo khi c mt ca acid v ng.

Pectin kt hp vi tanin to thnh hp cht khng tan.

Khi un nng trong nc pectin b ph hu.

Nh vy hemicellulose, cellulose v pectin ngn cn cc qu trnh nghin, p, lc,

trong sn xut nc p rau qu.

- Hemicellulose, cellulose trong rau qu khng tan trong nc lm cn tr qu trnh p rau qu l nh hng n lng dch p thu c.

- Nc p rau qu l sn phm ch bin t qu thng qua vic tch dch qu bng nhiu phng php khc nhau. Vic lm trong dch qu trong thi gian ngn l rt kh

khn bng phng php lng lc. Mc trong ca nc qu c vai tr n gi tr cm

gic ca sn phm. M nguyn nhn lm nc p khng trong l pectin

- x l pectin ngi ta s dng enzyme pactimase qu trnh lc d dng hn. Pactimase (hay cn gi l pectinesterase) c tc dng hu hiu trong vic lm

trong dch rau qu p. S dng pectinase s a hiu qu cao bi: Lng pectinase

s dng t nhng hiu qu lm trong cao v nhanh thay th cho phng php ho -

l (lng lc t nhin) km hiu qu, d nhim khun v thi gian di.

Di tc dng ca pectinase, pectin - mt polysacharid c to thnh t s lin

kt gia cc mch ca phn t axit galacturonic (C6H10O7) m mt phn ( mc

khc nhau) c este ho vi ru metylic (CH3OH) b phn hu hoc b

phn ct lin kt glucozit. Pectin l 1 cht in ly cao phn t (polime) mang in

tch m (-) dc theo chiu di ca mch phn t c s sp xp cc nhm din tch

36

cng du (-COO-) nn mch c xu hng dui thng to nn b mt hp ph ln

trong ton b dung dch c cha pectin.

Nc qu c l h huyn ph trong phn t sn (tht qu) c kch thc nh,

b mt ring ln v c nng lng rt ln nn khng bn vng v mt nhit ng

hc. Mt khc, chng l nhng phn t tch in nn di tc dng ca lc ht

phn t chng lin kt li to thnh nhng phn t ln d dng sa lng. Trong

nc qu, s c mt ca hp cht polyphenol (c bit l tanin) to nn vi pectin

nhng kt ta khng tan v.v... S c mt ca pectinase s thc y nhanh qu trnh

c bn nu trn.

Chng 4: Cng ngh sn xut thu nhn cht x t rau qu

I. Tnh hnh ngin cu sn xut cht x

Nm 1970 Pilnik nghin cu thu nhn pectin t qu to.

Nm 1984 De Vries so snh cu trc pectin thu c t to vi pectin thu c t

v citrus.

Nm 1990 May thu nhn pectin t v cam ng dng trong thc phm v dc

phm.

Nm 2004 Chau thu nhn cht x khng ho tan t ht qu chanh dy.

Nm 2006 T. Prakongpan nghin cu sn xut cht x t li da vi phng

php trch ly bng cn.

Nm 2006 ti c v v 11 nh sn xut thc phm trin khai d n sn xut

cht x thc phm t u tng v ng dng trong cc sn phm nh sp n lin,

bt lm bnh, pizza, ung, cc loi xc xch.

Ti Nht cui nm 1990 mt s loi oligosaccharit c sn xut quy m cng

nghip maltooligosaccharit, Iso maltooligosaccharit, FOS, cyclodextrin.

II. Cc quy trnh sn xut cht x t rau qu

37

1. Quy trnh chung :

Qu trnh sn xut pectin c th khc nhau gia cc cng ty nhng quy trnh chung bao

gm cc bc nh sau:

Nh my thu nhn b to hoc v tri cy c mi t cc nh sn xut nc tri

cy. Trong nhiu trng hp nguyn liu ny c ra v sy c th vn

chuyn v bo qun m khng b h hng Nu nguyn liu th kh, n c th

c ly t trong kho. Nhng khi sn xut t v tri cy t phi s dng ngay v

chng h hng rt nhanh

Nguyn liu th c cho vo nc nng c cha cc cht h tr cho qu trnh

chit nh acid hoc enzyme Nu ch dng nc khng th ch chit c mt

lng gii hn pectin

Sau mt khong thi gian chit pectin, cht rn cn li s c tch ra; v dung

dch c lc, c c bng cch loi nc. Cht rn c th tch ra bng thit b

lc, thit b ly tm hoc cc thit b khc. Dung dch sau c lc li 1 ln na

nu cn thit hoc l ngay lp tc, hoc sau 1 khong thi gian bin tnh pectin,

cht lng c c s c trn vi cn kt ta pectin. Pectin c th c deester

ha phn no giai on ny; hoc sm hn hay tr hn trong quy trnh

Cht kt ta c tch ra, ra vi cn loi b tp cht v c sy.

Cn c dng c th cha cc mui hay kim bin i pectin thnh dng

mui 1 phn (Na+, K+, Ca2+, NH4+) Cn (thng dng l isopropanol) c

thu li v c dng kt ta thm pectin

Trc khi hay sau khi sy, pectin c th c x l vi NH3 sn xut pectin

amid ha.

Pectin amid ha c a chung hn trong 1 vi ng dng

Cht rn c nghin thnh bt, kim tra v trn vi ng hay dextrosehnh

thnh kh nng to gel tiu chun hay nhng tnh cht khc nh kh nng to st,

kh nng n nh. Pectin cng c trn vi nhng ph gia thc phm c chp

nhn khc v dng trong nhng sn phm c trng.

38

2. Quy trnh sn xut cht x khng ha tan v ha tan t b nhn sm

Sn xut cht x khng ha tan

Gii thch quy trnh

B nhn sm c sy kh v nghin sau c a vo my p n trc vt i

vi t l L/D l 20 ~ 40. iu chnh my chy vi tc 400 vng/pht, t l sn phm

20 ~ 60 kg/h, m 15 ~ 40 %. Thm b c p n vo nc n nng 1 ~ 10%

(w/v), khuy trn v ly tm mu thu phn ni trn b mt v phn kt ta pha di.

Lm kh kt ta thu c bng cch ly tm thu cht x khng tan t b sm.

39

T lL/D 20~ 40Tc 400v/phT l sp 20 ~ 60 kg/h m 15 ~ 40 %

1 ~ 10% (w/v)

B nhn sm

Sy

Nghin

p n

Khuy trnNc

Ly tmDch ni

Cht x khng ha tan

Sy

Sn xut cht x khng ha tan

40

T lL/D 20~ 40Tc 400v/phT l sp 20 ~ 60 kg/h m 15 ~ 40 %

1 ~ 10% (w/v)

B

B nhn sm

Sy

Nghin

p n

Khuy trnNc

Ly tm

Cht x ha tan

Ta isopropanolisopropanol

Sy

Gii thch quy trnh

- B nhn sm c sy kh v nghin sau c a vo my p n trc vt

i vi t l L/D l 20 ~ 40. iu chnh my chy vi tc 400 vng/pht, t

l sn phm 20 ~ 60 kg/h, m 15 ~ 40 %.

- Thm b c p n vo nc n nng 1 ~ 10% (w/v), khuy trn v li

tm mu thu phn ni trn b mt v phn kt ta pha di.

- Gn ly phn ni trn b mt v dch lc, thm isopropanol vo dch lc, lng

isopropanol thm vo bng 3~5 ln lng dch lc, thu c kt ta th hai,

lm kh kt ta th hai ta thu c cht x ho tan t b nhn sm.

3. Quy trnh sn xut cht x ha tan t v chanh dy

Gii thch quy trnh

- V qu c ra sch sau em chn qua dung dch acid citric 5% vi nhit

100oC trong 5 pht.

- Sau em ly tm 1200 vng/ pht trong 10 pht. Gn ly phn b em i

nghin t kch thc

- Tip n lc v ra ethanol 2 ln thu hi ethanol, phn kt ta em i sy

nhit thp l 22oC, tc khng kh 4,5m/s trong 2,5h n m 25%.

- Sau em sy i lu nhit 50oC, m khng kh 25%, tc gi

5m/s trong 30 pht n m 14% ri em i nghin mn thu c sn phm

cht x ha tan (pectin)

42

1200v/p/10ph

70%w/v

V Qu

Ra sch

Chn qua dung dich acid

Li tm

Nghin nh

Thy phn HCl

Li tm

Ta cn

Lc-Ra Ethanol (2 ln)

B

Sy i lu

Sy nhit thp

Thu hi

Ethanol

Nghin mn

SP cht x ha tan

(pectin)

100oC/5 pht

4. Cng ngh sn xut cht x khng tan t b da

43

100oC/30phKim/ b 8/1

B da

X l

Thy phn

Lc

Ra

Ly tm

Ra cn

Sy

Nghin

Kim

90oC, t l 8/1 pH 6-6,5

Nc

t l 3/1Cn 96o

100oC/4,5h m 6-7%

0,51mm

Cht x khng ha

tan

Gii thch quy trnh

- B da sau khi x l em i thy phn bng dung dch kim nhit 100oC

trong 30 pht vi t l kim trn b l 8/1.

- Sau em lc ri ra li bng nc nhit 90oC vi t l 8/1 pH t c

6-6,5. Tip n ly tm, gn ly phn kt ta ri em ra bng cn 96o vi t l

3/1

- K tip em sy nhit 100oC trong 4,5h n m 6-7% ri em nghin

t kch thc 0,5 -1mm thu c cht x khng ha tan.

5. Quy trnh chit pectin t ph liu bi

Gii tch quy trnh

- Nguyn liu c x l (ra, x) loi b tp cht, phn ci v b ca qu

bi c ra sch, tch ht, ct nh ri ra bng nc m (50-60oC) loi

b cc glucoside cn st li. Sau a nhit ln ti 95 980C lm mt

hot tnh ca enzyme phn gii pectin.

- S dng thit b nghin ba hay thit b c s dng con ln va p xay nh

nguyn liu.

- Sau dng acid HCl, (thng ngi ta dng lng nc gp 3 ln lng v

kh), pH = 1,3 1,4, nhit 90 1000C v thi gian un l khong 1 gi.

Kt thc khi kh dung dch t 2% (pectin 0,7 1,0%; ng 1

1,3%).Trong khi trch ly cn khuy trn u tng tc khuch tn tng

tc trch ly.

- Tip n dng enzyme phn gii protein thc hin pH = 4,5 5 (iu chnh

bng dung dch natri cacbonate) v nhit 40 500C. Khi loi b ht

tinh bt (kim tra bng iod), iu chnh dung dch pH = 3 bng cch thm acid

citric ri a nhit ln 800C lm mt hot tnh ca enzyme.

- S dng thit b p v thit b lc loi b phn b khng tan trong dung

dch. Lm sch v lng gn thu c dung dch pectin trong sut.

44

- Tip n c c n kh 10% thu c ch phm pectin vi hm lng 4

5% em bo qun nu mt. C c trong chn khng nhit 55 600C

v chn khng t 600 mmHg tr ln thu c ch phm pectin c c.

- Ch phm thu c rt vo bao b, em thanh trng v bo qun nhit

khng qu 300C, m khng kh: 85%, thi gian bo qun 6 7 thng.

- Ch phm thu c sau khi c c ng t pectin lng bng cn ethylic 950C

ri lc tch pectin khi hn hp ru - nc. Sau kt ta pectin c ra

li bng cn 900C. Tip n em sy chn khng 60-70oC n khi m cn

3-4% ri em nghin nh v cho vo bao bo qun.

45

46

Nguyn liu

X l

Xay nh

Trch ly

Trung ha

p

Lc

C c chn khng

Thanh trng

Kt ta

Ra b

Lc ly b

Sy chn khng

Nghin nh

Rt bao bBao b

Dd HCl long

Dd Na2CO

3

Bt pectin

Pectin c c

B p

B lc

Dch lc

pH 1,3-1,4; 90-100oC 1h kh t 2%

Acid citric

pH 4,5-5; 40-50oCpH 3; 80oC

kh 10%, HL pectin 4-5%, 55-60oC, 600mmHg

Ethylic 95o

Cn 90o

60-70oC, m 3-4%

III. Cc ch phm cht x trn th trng

Thnh phn: Cht x thc phm (Polydextrose), cht xenlul t ng, tinh cht

xenlul.Ch tiu cht lng ch yu: Mi 100g sn phm c: 40g cht x Thc

phm. Hm lng mi vin (mg): Cht x thc phm (Polydextrose) : 400, 00

Cht xenlulo t ng : 100, 00 Vi tinh cht xenlulo : 30, 00

Cch s dng: Mi ngy ung 3 ln, mi ln 3 4 vin.

i tng s dng: tr em, thiu nin, trung nin, ngi gi. (Tr s sinh khng

nn dng.)

Bo qun: Ni rm mt, kh thong.

Thnh phn: Fructo Oligo saccharide ( FOS), T dc va cho 5g.

Cng dng:

- B sung cht x thc phm, c tc dng lm tng khi lng b thi, to khi

phn, gip bnh thng ha tnh trng phn v s ln i tiu, phng chng to

bn v cung cp nng lng hot ng cho t bo rut gi.

47

- Duy tr s cn bng cc vi khun c li ng rut, ti u ha vic hp thu

cc dng cht tr, gim nguy c nhim trng ng rut, gp phn lm cho

h min dch hot ng tt hn.

- Tng cng hp th canxin.

- Gip gim ch tr bo ph.

i tng s dng: Tr ri lon tiu ha gay to bn, hoc to bn do cc nguyn

nhn khc nhau. Tr bo ph cn gim ch n.

48

Ti liu tham kho

1. Quch nh, Nguyn Vn Tip, Nguyn Vn Thoa, Cng ngh sau thu hoch v ch bin rau qu, Nh xut bn Khoa hc k thut H Ni, 1996

2.http://d.violet.vn/uploads/resources/50/469886/preview.swf3. http://mobi.vietbao.vn/vi/Suc-khoe/Chat-xo-trong-dinh-duong/45129522/248/4. http://www.duoclieu.org/2012/01/pectin.html5.http://vietbao.vn/Suc-khoe/Vai-tro-cua-chat-xo-trong-dinh-duong-hop-

ly/40059815/248/6.http://www.ykhoa.net/duoc/dinhduong/05_0018.htm

49

http://www.ykhoa.net/duoc/dinhduong/05_0018.htmhttp://vietbao.vn/Suc-khoe/Vai-tro-cua-chat-xo-trong-dinh-duong-hop-ly/40059815/248/http://vietbao.vn/Suc-khoe/Vai-tro-cua-chat-xo-trong-dinh-duong-hop-ly/40059815/248/http://www.duoclieu.org/2012/01/pectin.htmlhttp://mobi.vietbao.vn/vi/Suc-khoe/Chat-xo-trong-dinh-duong/45129522/248/http://d.violet.vn/uploads/resources/50/469886/preview.swf