cong nghe che bien tra xanh dong lon

NC TR XANH NG CHAI GVHD: Thy L Vn Vit Mn

Trang 1

LI M U Tr xanh l nguyn liu dng ch bin thc ung ph bin trn th gii t hng nghn nm nay, c bit cc nc khu vc chu nh Trung Quc, i Loan, Nht

Bn, Hn QucUng tr c nng ln thnh ngh thut vi nhng nghi thc c

bit v trang trng.

Cuc sng cng nghip tt bt khin ngi ta khng th chun b cho mnh mt

tch tr xanh theo cch truyn thng, l c hi kinh doanh ln cho nhng nh sn xut nc gii kht hng u. Tr xanh xut hin di nhiu dng bao b, phc v cho nhiu nhu cu, i tng khc nhau. Tuy nhin, tr xanh ng trong chai PET hoc

ng lon gn y tr thnh mt xu hng ph bin v n tin dng, mi lc mi ni v cng tr thnh mt phong cch ung tr ca gii tr.

Trn th gii, tr xanh ng chai pht trin mnh t thp nin 80 ca th k trc. Vit Nam, t nm 2006 khi Tn Hip Pht tung ra v thng ln vi Tr xanh

khng , cc tp on ln cho ti cc nh u t nh l lao vo nhm n theo ming

mi thm ngon bo b ny. V thi im gn y, cuc chin gia cc thng hiu din ra khc lit nht: Tr xanh Khng ca Tn Hip Pht, C2 ca URC, Lipton Pure Green_ sn phm kt hp ca hai i gia Pepsi v Lipton...

ti bo co chng em xin trnh by ch yu v "Quy trnh sn xut Tr xanh ng chai". ti ny lin quan n xu hng pht trin mi ca tr xanh, y l ti kh mi m nn trong qu trnh thc tm t liu, thng tin, nhm em gp kh nhiu kh

khn, nhng nh s ch dn tn tnh ca cc thy c thuc B mn Cng ngh thc phm, m c bit l thy L Vn Vit Mn, nhm em hon thnh ti ny, xin cm n s gip ca qu thy c, cng nh cm n s ng vin, gip ca cc bn

trong qu trnh thc hin ti.

Bi bo co ca nhm em khng trnh khi thiu st, xin qu thy c ch dn

thm, gip chng em c kinh nghim thc hin nhng bo co tip theo, xin chn thnh cm n.


Trang 2

I. GII THIU NGUYN LIU I.1 Ngun gc ra i ca cy tr (ch): Theo truyn thuyt, vo nm 2737 trc Cng nguyn, mt v Hong ca Trung Quc tn l Sheng Nung ang ngi ung nc di mt gc cy th bng nhin c mt l cy rt ngay vo ly nc ca ng ang ung. S c mt ca chic l trong nc nng to ra mt thc ung c hng v rt c trng, khi ung vo khin cho ngi c cm

gic minh mn, sng khoi khc thng. T , tr ra i.

Ngy nay, tr tr thnh mt thc ung ph bin trn ton th gii v c tnh c

khong 20 t tch tr c ung mi ngy.

Hnh 1:Tr xanh Hnh 2: Tr c pha thng thc

Ngoi ra, tr cn c nhng dc tnh qu gi c cc nh khoa hc nghin cu ngy cng nhiu ng dng phng nga v cha bnh trong cc sn phm thc phm cng

nh m phm.

Hnh 3: Kem PS tr xanh cha nhit ming


Trang 3

I.2 Mt s cng dng ca tr xanh:

Tr xanh gip phng chng bnh ung th v:

Nhng cht Polyphenol c trong tr xanh c vai tr quan trng trong vic phng chng

bnh ung th. So vi tr en th tr xanh c hm lng polyphenol cao hn v khng b qu trnh men lm thay i thnh phn. c bit, cht chng oxy ho EGCG (epigallotechin gallate) l loi polyphenol v cng mnh m , l nhn t ch yu to nn dc tnh ca tr xanh. N c cng dng ngn nga cc enzyme kch hot s sao chp nhn bn t bo.

Trong nhiu th nghim khc nhau nhng con chut b khi u v c cho ung tr

xanh, so snh vi nhng con chut tng t cho ung nc l. Kt qu cho thy nhng con chut cho ung tr xanh gim kch thc khi u, cn nhng khi u mi chm pht trin hn. Cc nh khoa hc Nht Bn vin nghin cu ung th Saitama khm ph

ra rng nhng ph n c thi quen ung hn 5 tch tr xanh mi ngy thng t c nguy c mc bnh hoc ti pht bnh ung th v v bnh khng di cn nhanh chng nh

nhng i tng bnh thng khc

y l mt thng ip tt p ph n quan tm n tr xanh . t c nhng li ch sc kho,bn ch cn ung 3-4 tch mi ngy v tt hn na l khng nn pha thm ng hay sa.

Tr xanh v bnh vim khp:

Tin s Tariq cng tc ti trng i hc Western Reverve Cleveland, Ohio (M), cng nhm nghin cu tm hiu tc ng ca polyphenol i vi bnh vim khp tin

trin tng dn vi cc triu chng: vim sng, au nhc, thoi ho khp.

Nhng con chut trong phng th nghim cho ung: hoc l nc tr xanh vi liu lng tng ng 4 tch mi ngy ngi hoc l ung nc l. Sau chng c

th nghim b tim collagen vo nhm mc ch gy ra bnh vim khp tin trin tng

dn ngi. Kt qu nghin cu cho thy con chut ung tr xanh t b vim khp hn so vi con chut ung nc l. Tuy nhin cho d chng c mc bnh vim khp i chng na th con chut ung tr xanh ch mc bnh s si vo mt thi gian kh lu sau .

C mt nhn xt th v rng cc quc gia nh n , Trung Quc, Nht Bn nhng ni xem tr l thc ung hng ngy th bnh vim khp gim hn so vi nhng ni khc trn th gii.

Tr xanh v bnh tim:

Vo thng 5/2002 tp ch "Circuration" ca hi tim mch M cng b cho thy tr

xanh nu c ung thng xuyn s gip ch cho cc bnh nhn bnh tim mch.


Trang 4

Kenneth J Mukamal mt bc s kim thc s cng tc ti mt trung tm y khoa Beth Israel Deaconess cho bit "nhng li ch v sc kho ln nht ca tr xanh c tm thy nhng bnh nhn tim mch". Mukamal cng cc cng s khm ph ra rng sau khi pht cn au tim nhng bnh nhn nghin tr xanh c nng "" c t l t vong t hn 44% so vi bnh nhn khng

ung tr, cn nhng bnh nhn ung tr xanh mc va phi c t l t vong t hn 22% so vi nhng ngi khng ung tr. Cha kha cho tnh nng bo v sc kho ca tr xanh chnh l cc flavonoid. Flavonoid hin din trong c tr xanh, tr en, trong mt

s loi rau, to, hnh, bng ci, c kh nng ngn nga cholesterol xu LDL khng b oxy ho, chng t mu, chng x cng ng mch. Tuy nhin, Mukamal cng lu rng cn phi c thm nhiu nghin cu lm sng na ngay trn c c nhn mnh kho ln bnh tt.

Tr xanh c cng nng dit khun E-coli O-157:

Thng 8/1996 gio s T. Shimamura cng tc ti trng i hc y khoa Showa (Nht

Bn) c cng trnh din thuyt "v tc ng dit khun E-coli-157" ti hi tho chuyn dit khun ca tr xanh.

Catechin hp cht to nn v ng ca tr xanh c cng dng hu hiu trong vic tiu dit hu ht cc nhng loi vi khun gy ng c thc phm v gii tr lun nhng c t do vi khun tit ra c th y l c t Veratoxin ca Ecoli -157. Nu ung tr xanh trong v sau ba n s pht huy c c ch cht Catechin tiu dit t bo ngoi ca vi

khun. Trong cc th nghim ny tr xanh c ngm trong nc mui to ra hp cht pha long nng 2,5% - 5% so vi tr bnh thng. Cn khi ngm vi nc nng cht Catechin c gii phng nhiu hn nn tc ng dit khun cng c ci thin.

Mt s hp cht ho hc v li ch sc kho khc ca tr xanh:

Catechin gim nguy c t bin gen, gim cholesterol, cao huyt p, ng mu, dit vi

khun cm, nga su rng, hi th hi. Caffeine gip bn tnh to gim mt mi, bun ng, dng nh cht li tiu.

Vitamin C gim stress, nga cm cm. Acid Gama-AminoBityric(GABA) h huyt p. Flavomoid tng cng sc kho thnh ng mch, nga hi ming.

Polysaccharide nga tng ng mu

Fluoride nga su rng.

Vitamin E nh l cht chng oxy ho duy tr tui xun

Theanine tng cng khu v

I.3 c im thc vt ca cy tr: I.3.1 c im:


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Hnh 4: Cy tr Hnh 5: Hoa tr Hnh 6: Bp tr 1 tm v 2 l non

Hoa tr: Mu trng vi nhiu nh vng. Mi ho a gm 7 cnh v hng t nh di. Qu tr: thng mc thnh tng chm 3. Ban u c mu xanh ca chi, sau tng

trng v cng dn thnh qu mu nu cha ht bn trong. Khi qu chn, vt rnh m ra. Ht bn trong c th c dng gieo trng. Thn cy: n trc; 3 loi: thn g, thn bi v thn nh (bn g).

L tr: mc cch trn cnh, mi t c mt l, hnh dng v kch thc thay i ty

ging. L tr c r gn, ra c rng ca. Bp tr: l giai on non ca mt cnh tr, c hnh thnh t cc mm dinh dng,

gm c tm (phn l non trn nh cha xe) v 2 3 l non. C hai loi bp: bp bnh thng v bp m.

Trn 1 cnh tr: 1 nm c 4 5 t sinh trng ca bp.

I.3.2 Phn loi thc vt:

Ngnh Ht kn Angiospermae Lp Song t ip Dicotylednae B Ch Theales H Ch Theaceae

Chi Ch Camellia (Thea) Loi C.sinensis Tn khoa hc: Camellia sinensis (L) (hay Thea sinensis L.) (1935 Hi ngh Quc t v thc vt)

Tm tr

L non


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I.3.3 Thu hi, vn chuyn, bo qun v nh gi cht lng nguyn liu ch sau thu hi:

I.3.3.1 Thu hi: nh ta bit nguyn liu ch l tm vi cc l non (1,2,3,4). Sau y l cc phng php thu hi ch:

Thu hi lin tc: khi thn cy ch xut hin cc nhnh non gm c tm vi 4 5 l non th bt u hi tm vi 3 l non, cha li cnh vi 2 3 l pht trin cy ch s ny

nhnh non v c thu hi tip tc cho n khi kh nng ny bp ca cy ch gim hn

th kt thc ma thu hi.

Phng php tn thu: trong sut ma thu hoch, ngi ta hi ht cc tm vi 3 l non.

Phng php ny p dng vo cui ma thu hi trc khi tin hnh n ch.

Phng php iu ha: p dng i vi nhng cy ch hay nng ch c kh nng ny bp km, cn ci. Khi ch hi bp mt chng mc nht nh tp trung chm sc,

vo ma thu hi sau s cho nng sut cao hn.

Bng 1: Cht lng ca nguyn liu ch thu hi theo 3 phng php trn nh sau

Phng

thc hi

Trng lng bp - g Cht lng bp

Bp pht trin Bp m Cht tan - % Tanin -

%

Hng -

im

V -

im

Lin tc

Tn thu

iu ha

0,42

0,37

0,30

0,32

0,27

0,30

43,26

43,40

42,96

19,22

20,12

19,15

100

100,6

101,4

100

104,3

100

Cht lng nguyn liu ch thu hi theo phng php tn thu c cao hn cc phng

php kia do cc tm non hn, trng lng bp nh hn.

Cc phng php tn thu hi ch:

C gii: l cc my hi ch chy bng kh nn hay cm tay chy bng xng, ch c p

dng hn ch v a hnh trng ch.

Th cng: y l bin php thu hi ch yu t trc n nay, tc l hi trc tip bng

ngn tay v dng ko hi ch. Dng ko khi phi hi ta v to dng cho cy ch, lung

ch.


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Hnh 7: Cnh thu hi ch

I.3.3.2 Vn chuyn, bo qun ch bp:

Nguyn liu ch bp ti rt d b h hng, i ngt nn khi thu hi xong cn c cha ng, bo qun v vn chuyn nhanh chng v xng ch bin. Do c im cc vng nguyn liu ch thng nm tri di trn mt din tch canh tc ln, a hnh phn ln l i ni do phi lp cc trm thu gom, tn tr nguyn liu sau khi thu hi xong

chuyn v xng ch bin.

Nhim v ca cc trm l:

- Thu gom tt c nguyn liu c thu hi trong khu vc.

- S b phn loi v bo qun cc cp nguyn liu.

- Thng bo v xng ch bin s lng v cht lng nguyn liu hin c, mi trm phi c kh nng thu mua v bo qun c mt na lng bp thu hi trong ngy vo

thi k r nht.

Vic vn chuyn ch bp v c s ch bin c th bng nhiu phng tin khc

nhau:

- Xe ti c thng cha chuyn dng hay toa xe trn h thng cp treo.

- Cc phng tin th s do sc vt ko, dng c cha l st tre, b, bao ti.


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I.3.3.3 nh gi cht lng nguyn liu ch sau thu hi:

Khi nguyn liu ch va thu hi l mt hn hp gm cc tm v l non, cc bp khng pht trin (bp khng c tm, cn gi l bp m) vi cc l non, cc l ch gi ri V

th cn phi phn loi nh gc thu mua v nh gi cht lng.

- Bin php c gii: dng my phn loi ch chuyn dng v c p dng khi thu hi

ch bng my.

- Bin php cm quan: phn loi theo cc tiu ch sau y: nguyn liu cng nhiu bp

non th cht lng cng cao v ngc li nguyn liu cng nhiu bp gi th cht lng

cng thp, khi lng trung bnh ca cc bp cng nh th cht lng cng cao.

Cng thc thc nghim nh gi tng qut cht lng nguyn liu ch c dng :


Trang 9

I.4 Thnh phn ha hc ca nguyn liu: I.4.1 Thnh phn ha hc ca l tr ti:

Hnh 8: Thnh phn cc cht c trong l ch ti

1- Nc :

Cht kh (20-25%)

Cht kh khng ho tan trong nc

Nc (75 80%)

L tr ti

Cht kh ho tan trong nc

+ Catechin + Vitamin

+ Acid amin + Saponin

+ Caffein + Fluoride

+ Saccharide + Flavonoids

+ Cht khong + Pectin

Khng tan trong du

+ Cellulose

+ Protein

Ho tan trong du

+ Carotene

+ Vitamin E

+ Chlorophyl


Trang 10

Bng 2: Thnh phn ha hc ca tm tr ti

Thnh phn % khi lng cht

kh

Polyphenol 25 30

Epigallocatechin gallate 8 12

Epicatechin gallate 3 6

Epigallo catechin 3 6

Epicatechin 1 3

Catechin 1 2

Gallocatechin 3 4

Flavonols v flavonol glucosides 3 4

Polyphenolic acids and depsides 3 4

Leuco anthocyanins 2 3

Chlorophylls v cc cht mu khc 0.5 0.6

Khong 5 6

Caffeine 3 4

Theobromine 0.2

Theophylline 0.5

Amino acid 4 5

Acid hu c 0.5 0.6

Monosaccharide 4 5

Polysaccharide 14 22

Cellulose v hemicellulose 4 7

Pectin 5 6

Lignin 5 6

Protein 14 17

Lipid 3 5

Cc hp cht bay hi 0.01 0.02


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Bng 3: Thnh phn ha hc lin quan n mu, mi, v ca tr

Thnh phn Mu Thnh phn V Thnh phn Hng

Theaflavins

Thearubigins

Flavonol glycoside

Pheophorbide

Pheophytin

Carotene

Nu vng

Nu

Vng sng

Hi nu

Hi en

Vng

Polyphenol

Amino acid

Caffeine

Theaflavin

Thearubigin

Cht

D v ngt

ng

Cht

Hi cht

Linalool, Linalool oxide

Phenylacetaldehyde,

Geraniol

Nerolidol,Benzaldehyd Methyl salicylate,

Phenyl ethanol

Trans-2-Hexenal, Grassy

n-Hexanal, b-Ionone, Cis-3-Hexenol,

Ngt

Hng hoa

c (Floral)

Tri cy

Hng ti

(Fresh flavour)

I.4.1.1 Nc

Trong l tr, nc l mi trng xy ra s tc dng tng h gia cc cht ha tan. Ngoi ra, nc cn l thnh phn chnh tham gia vo cc phn ng thy phn v o xy ha

kh xy ra khng ngng trong cc t bo ca l. Xt thnh phn khi lng, nc l thnh phn ch yu ca l tr. Theo s liu ca Phng nghin cu tr v cc cy trng nhit i Lin bang do R. Xiloxantri v hm lng nc trong bp tr gm mt tm ba l trong cc thng bng % c th hin bng 3:

Bng 4: Thnh phn m thay i theo thng trong nm.

Thng 1 2 3 4 5 6 7 8 9 10 11 12

m,%

63.

6

63.

6

62.

9

77.

3

77.

5

77.

5

78.

5

77.

8

77.

2

75.

6

73.

5

70.

3

I.4.1.2 Hp cht polyphenol

Cc hp cht polyphenol trong tr c chia thnh 4 nhm chnh: - Hp cht catechin - Hp cht anthoxanthin - Hp cht anthocyanne - Cc acid phenolcarboxylic cng cc hp cht khc

a. Hp cht catechin:

C 6 loi catechin trong tr, bao gm: - D, L catechin

- L epicatechin


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- D, L galocatechin - L epigalocatechin - L epigalocatechinsingalat - L galocatesingalat Cc catechin trn chnh l thnh phn chnh ca cht tannin trong tr. Catechin gy nn

v ng v cht nh cho tr. Catechin l tc nhn chnh to mu cho nc tr khi qua ch bin.

Bng 5 : Cc cht catechin trong hn hp tannin ca bp tr ba l, ging tr Grudia

(theo%)

( ) catechin

OOH

OH

H

OH

OH

OH

H

0.4

(-) epicatechin

OOH

OH

H

OH

OH

OH

H

1.3

( ) galocatechin

O O H

O H

O H

O H

H

O H

H

O H

2.0

(-) epigalocatechin

OOH

OH

OH

OH

H

OH

H OH

12.0

(-) epicatechingalat

OOH

OH

OH

OH

H

OH

H

O

O

OH

OH

OH

18.1


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(-)

epigalocatechingalat

OOH

OH

OH

OH

H

OH

H

O

O

OH

OH

OH

58.1

(-) galocatechingalat

OOH

OH

OH

OH

H

OHHO

O

OH

OH

OH

1.4

Ch phm catechin tr c dng nh mt vitamin P rt cn cho c th ngi (ngi ln cn 200mg v tr em cn 100mg mi ngy). Hin nay, ngi ta thit lp c phng

php thu nhn ch phm catechin (vitamin P) t l tr gi v dng cha bnh c hin tng chy mu trong c th do nhim c cc mao qun, cha bnh huyt p cao v t thp tim. Ch phm catechin ca tr c tinh khit cao, c tc dng cha bnh nhim phng x v c hot tnh ch thua km natrigalat. b. Hp cht anthoxanthin:

Ngi ta tm thy mt s anthoxanthin c trong l tr thuc cc ging khc nhau:

- Campherol v cc glycoside ca n.

- Quexectin v cc glycoside ca n.

- Miricetin v cc glycoside ca n. Anthoxanthin c v ng cht, tham gia vo s to mu cho nc tr nhng khng nhiu do c lng tng i t so vi hp cht catechin.

c. Hp cht anthocyanne:

Tn ti trong tr di dng lin kt vi mt gc ng, tan trong nc, mu sc ph thuc vo nhiu yu t khc nhau nh nhit , nng v thnh phn cc hp cht khc.

Hp cht anthocyanne c v ng, trong l tr cng cha nhiu anthocyanne th v cng ng khng hp khu v ngi tiu th.

d. Cc acid phenolcarboxylic:

L cc hp cht hu c c cng thc ho hc va cha gc phenol va cha gc cacboxyl. Trong l tr ti c cha nhiu cht thuc cc acid phenolcacboxylic. Cht n gin nht tm thy trong l tr l acid galic.


Trang 14

Ngoi ra cn tm thy cc acid sau: - Acid elagic

- Acid metadigalic

- Acid izolorogenic

- Acid clorogenic

- Acid cafeic

- Acid paracumaric

- Acid paracumarilquinic

- Acidgaloilquinic Cc acid phenolcacboxylic trong tr c hm lng khng nhiu, tuy nhin, cc hp cht ny gp phn to nn v tr c trng.

Phc cht tannin (cht cht)

Trong thnh phn ha hc ca tr ti hay tr thnh phm, cht cht (hay cn gi l phc cht tannin) gi mt v tr ht sc quan trng v n quyt nh cht lng ca tr. Tannin

khng nhng to nn v c o cho tr m cn tham gia vo cc qu trnh bin i ha hc di tc dng ca cc enzyme oxy ha to ra hng thm v mu sc c trng

cho mi loi tr. Tannin khng phi l mt n cht m l mt hn hp phc tp ca cc hp cht c c tnh polyphenol. Trong thnh phn ca phc cht tannin ca tr gm c cc polyphenol catechin n gin, cc sn phm oxy ha ca chng. Di tc dng ca nhit v m, sn phm thu c l tr xanh c v cht mnh, hu

ngt, c nc mu xanh ti hoc xanh vng, c mi thm c trng.

e. Hp cht alkaloid

Alkaloid l nhng cht khng mu, mt s t c mu vng, chng c tnh kch thch u

li, c v ng. Thnh phn ch yu l caffeine.

Caffeine c cng thc phn t: C8H10N4O2, cng thc cu to:

CH3N

O

N

CH3

N

N

CH3

O

Caffeine l cht alkaloid ch yu v quan trng nht trong l tr, c v ng, khng mi. Caffeine tc dng vi tannin tr s to thnh vng khi ngui nc tr, gi l hp cht tanat cafein. Theo quan im ca mt s tc gi th caffeine c kh nng gi li s ng t ca

protein.


Trang 15

Bng 6: Hm lng caffeine ca l tr.

Cc loi l Hm lng caffeine (%)

L ti 2.87

L ho 2.61 L ln men 2.35

Cht lng tr ph thuc nhiu vo lng caffeine, caffeine cng nhiu th cht

lng cng gim, nhng khng th thiu caffeine trong thnh phn ca tr.

I.4.1.3 Protein

Protein l mt trong cc nhm cht ch yu v quan trng trong thnh phn ca l tr.

Trong qu trnh ch bin tr, protein l ngun cung cp cc acid amin t do v mt phn

protein b phn gii bi cc enzym tng ng to ra cc acid amin kt hp vi tannin hoc ng tr thnh cc aldehyde bay hi, gp phn tng cng hng thm cho tr.

Trong l tr, protein ch yu l protein c tnh tan trong kim nh glutelin. Ngoi ra, cn c protein ha tan trong nc, trong ru v trong acid. Cc hp cht cha Nit c trong

l tr vi hm lng rt ln, ch tnh lng protein cng chim ti 25 30% trng lng cht kh. Lng Nit trong l tr ti chim 4.5%, trong ch yu l Nit ca protein (khong 3%). V thnh phn acid amin c trong l tr , nhng phng php sc k trn giy tm thy 17 loi nh sau: alanin, serin, threonin, arginin, histidin, lysin, tyrosin,

phenylalanin, prolin, aspartic,

I.4.1.4 Acid hu c

Trong l tr ti, ngi ta tm thy cc acid hu c sau y:

Acid oxalic ha tan 0.20%

Acid oxalic khng ha tan 0.82%

Acid malic 0.30%

Acid citric 0.103% Acid succinic 0.006%

Cc acid hu c k trn trong cc cng on ch bin thng c s thay i v s lng.


Trang 16

I.4.1.5 Glucid

L tr cha hu ht cc loi ng nh: glucose, fructose, galactose, maltose, citose, arabinose, ribose, Hm lng monose trong l tr ch chim 1 2% v saccharose chim t 0.5 2.5%. Trong khi , hm lng cc polysaccharide trong l tr ln n 10 12% v cao hn na. L cng gi th lng ng kh v saccharose cng

nh tng lng ng ha tan cng ln. Lng tinh bt, cellulose v hemicellulose cng tng theo mc trng thnh ca l tr . Nh vy, nguyn liu cng gi, cht lng ca n cng km, hay ni cch

khc, quy lut bin i hm lng ca cc hydratcarbon trong l tr ngc li vi quy lut bin i hm lng ca cc hp cht c gi tr (tannin, caffeine, protein, ). Do , hm lng hydratcarbon trong l tr cng cao (ch yu cha cc polysaccharide khng tan) th cht lng tr cng thp.

Tuy nhin, cc ng ha tan trong l tr d hm lng rt thp nhng chng c ngha quan trng i vi cht lng ca tr. Trc ht, chng gp phn iu ha v tr, nhng quan trng hn c l cc ng kh di tc dng ca nhit cao hoc trong khi tc

dng vi tannin, acid amin c mt trong l tr s to cho tr c hng thm c trng v nh hng n mu sc ca nc tr. Chng hn, trong s tc dng tng h gia

glucose v fructose vi acid amin phenylalanin v tannin to thnh cc aldehyde bay hi c mi thm ca hoa ti, mi mt ong. Ngoi ra, cn nhn mnh rng, glucose v fructose di tc dng ca nhit cao trong qu trnh ch bin nhit cho tr s tham gia vo qu trnh caramel ha to cho tr c mi cm thm d chu.

I.4.1.6 Lipid

Cht bo l cht c tnh hp ph v l cht gi mi. Mt khc, bn thn cht bo c mt s cu t c sn mi thm d chu hoc di tc

dng ca nhit cao chuyn ha thnh cc cht c mi c trng gp phn tham gia trc tip vo s hnh thnh hng thm c o ca sn phm.

Ngoi ra, cng do cc tnh cht trn ca cht bo m lm cho tr d b nhim cc mi l v kh kh chng khi v tr tip xc vi cc vt c mi kh chu nh mi mc, mi bao b, mi du ha,

I.4.1.7 Pectin

Hp cht pectin thuc nhm hydratcarbon v l hn hp phc tp ca polysaccharide v dn xut ca chng. Phn ln cc cht pectin l nhng cht keo v

trong nhng iu kin nht nh th chng ng t li. Hm lng pectin trong l tr lun lun thay i, ph thuc vo nhiu yu t, trong quan st thy l tr cng non th cng cha nhiu pectin tan trong nc nhng tng hp pectin th cng t so vi l tr gi hn, c bit trong cng tr rt giu pectin.


Trang 17

Bng 7: Hm lng pectin trong cc b phn khc nhau ca bp tr (tnh theo % cht kh)

Nhm cht pectin Tm v l th nht

L th hai L th ba Cng tr

Ha tan trong nc 2.85 2.10 1.83 2.37 Ha tan trong acid oxalic 5.10 6.31 6.51 7.11

Ha tan trong amino oxalat 5.42 7.06 7.94 8.34

Hm lng pectin c lin quan mt thit n tnh cht ca tr ti v tr thnh phm, v d: trong qu trnh ch bin tr, pectin to ra tnh bm dnh gip cho tr cun cht li trong thi gian v hoc gip cho khi tr dnh cht vo nhau khi p nng trong

sn xut tr p bnh theo hnh dng ca khun. Pectin cng gp phn to nn v ngt du

ca tr thnh phm. Tuy nhin, pectin l cht keo ho nc, cng vi nhng cht khc c tnh ht m lm cho m trong tr kh tng ln, gy kh khn cho bo qun tr, v do

dn n lm gim cht lng tr.

I.4.1.8 Tinh du

Hng thm ca tr c hnh thnh bi cc yu t sau: - Lng tinh du c sn trong nguyn liu ban u. - Cc cu t mi ca tinh du c hnh thnh trong qu trnh ch bin tr (ch yu do cc qu trnh oxy ha, v di tc dng ca nhit cao), bao gm

+ Cc sn phm caramel ha khi ng kh chu tc dng ca nhit cao. + Cc sn phm ca s tng tc gia cc acid amin v ng kh di tc dng ca nhit v m - Cc cht c tnh hp ph v gi mi.

Trong , nhm aldehyde l mt trong nhng thnh phn cu t quan trng ca tinh

du tr. i vi cht lng tr, cc aldehyde bay hi gi vai tr quan trng, nh hng trc tip n hng thm ca n v bn thn mt s aldehyde sn c mi thm, hn na, chng cn tham gia vo s to thnh cc phc cht c mi thm c o ca tr, tham gia vo s hnh thnh mu sc v v nc tr. Ngoi cc aldehyde c sn trong nguyn

liu, tr cn c nhiu aldehyde mi c to thnh trong qu trnh ch bin tr.

I.4.1.9 Cht tro

Thnh phn tro ca l tr ti dao ng t 4 7%.

I.4.1.10 Vitamin

Nhm vitamin khng ha tan trong nc c trong l tr l vitamin K (liu lng 300 500 n v sinh l trong 1g tr). Ngoi ra, l tr cng cha nhiu vitamin C (1-acid ascorbic). Trong thi gian ch bin tr, hm lng acid ascorbic gim i ng k di tc dng ca nhit cao. Ngoi ra, trong tr cn c nhm vitamin B, c th l vitamin B1 (tiamin) v vitamin PP (acid nicotinic), vitamin B2 (riboflavin) v acid pantotenic.


Trang 18

I.4.1.11 Cht mu L tr c cha cc cht mu, nh lm cho tr c mu sc, cht mu thc vt gm t chlorophyll, anthocyan l nhng cht c trong phn nhm flavonoid v carotenoid c mu vng cng nh cc flavon v flavoncla. Cht mu u tin c xt ti l chlorophyll. Nh c chlorophyll m l tr c mu xanh

lc. Chlorophyll cng c cc tnh cht nh nhng cht mu khc l t ha tan trong nc nng hn so vi khi ha tan cng vi cc nhm cht mu khc trong dung mi hu c. Hm lng chlorophyll trong l tr nh hng xu n cht lng ca tr.

I.4.1.12 Enzyme

Enzyme l mt trong nhng nhm chnh c trong l tr. Phn ln enzyme y thuc nhm hydrolase. Cc loi enzyme thy phn thng gp trong l tr cn phi k

n l amylase, invertase, protease, Ngoi ra, cn c enzyme thuc nhm enzyme oxy ha kh.

I.4.2 Cc nguyn liu khc a) Nc

Nc c xem l nguyn liu trong cng nhip sn xut tr xanh ng chai. l do hm lng nc chim mt t l cao hn rt nhiu so vi cc hp cht ha hc khc trong sn phm. Ngoi ra, thnh phn ha hc ca nc nguyn liu s nh hng n nhng tnh cht cm quan v bn ha l ca sn phm thc ung.

Tnh cht:

Nhit ng c: 0oC

Nhit si: 100 oC

Ch s khc x ( 20oC) so vi khng kh: 1,333

Nhit nng chy: 6,012 KJ/mol

Nhit ha hi: 44,01 KJ/mol

nht: 1,004 MPa.s

Nhit dung ring p sut 0,101 MPa ca:

Nc (0oC): 1,039 J/kg.K

Nc (15 o

C): 4,185 J/kg.K

Hi (100 o

C): 2,039 J/kg.K

dn nhit ca:

Nc (0oC): 2,34 W/m.K


Trang 19

Nc (45oC): 64,5 W/m.K

Hi (100oC): 0,0231 W/m.K

Nc t nhin c xem l mt dung dch c cha cc hp cht v c v hu c. Ngoi

ra, trong nc cn c cc t bo vi sinh vt v mt hm lng nh cc kh ha tan.

Cht lng nc c nh gi ch yu thng qua ba nhm ch tiu: cm quan, ha l v

vi sinh.

b) ng:

Tnh cht

Danh php IUPAC: Saccharose

Tn khc: ng, ng ma, sacaroza

Phn t gam: 342.29648 g/mol

B ngoi: rn, trng

T trng: 1,587 g/cm

im nng chy: 186 C

ha tan trong nc: 211,5 g/100 ml (20 C)

Bng 8: ha tan ca saccharose tinh khit

ha tan ca saccharose tinh khit

Nhit (oC) g Saccharose/g nc

50 2,59

55 2,73


Trang 20

60 2,89

65 3,06

70 3,25

75 3,46

80 3,69

85 3,94

90 4,20

Hnh 9: Saccharose dng ht

Saccharose tinh khit thng thng nht hay c sn xut di dng bt kt tinh mn

mu trng, khng mi vi v ngt d chu; di tn gi ph bin l ng hay ng n.

N bao gm 2 monosaccharide l -glucose v fructose, c kt ni bng lin kt glucoside gia nguyn t cacbon 1 ca khi glucose vi nguyn t cacbon 2 ca khi fructose. Cn phi ch v saccharose khng ging cc polisaccharide khc, lin kt

glucoside c to gia ui kh ca c glucose v fructose, khng phi l ui kh ca monosaccharide ny v ui khng kh ca monosaccharide kia. Do khng c nguyn t

C t do c nhm epime, n c coi l ng khng kh.

Saccharose nng chy v phn hy 186 C to ra caramel (ng thng), v khi

chy to ra cacbon, dioxyde cacbon, nc. Nc c th ph v cu trc ca saccharose nh thy phn, tuy nhin qu trnh ny l rt chm v v th saccharose c th tn ti


Trang 21

trong dung dch trong nhiu nm m gn nh khng thay i. Tuy nhin, nu enzyme succarose c thm vo th phn ng s din ra nhanh chng.

Saccharose thng gp trong ch bin thc phm do n va l cht to ngt va l cht dinh dng; n l thnh phn quan trng trong nhiu loi thc phm nh bnh bch quy,

ko ngt, kem v nc tri cy, trong h tr trong bo qun thc phm.

Saccharose l cht dinh dng v m d dng tiu ha, l ngun cung cp nng lng nhanh chng cho c th, to ra s gia tng ca glucose huyt trong qu trnh tiu ha. Tuy nhin, saccharose tinh khit thng thng khng l thnh phn trong khu phn n

ca con ngi c thnh phn dinh dng cn i, mc d n c th thm vo lm cho mt s loi thc phm tr nn ngon hn.

Vic s dng qu nhiu saccharose c lin quan ti mt s cc bnh tt. Ph bin nht l

su rng, trong cc vi khun chuyn ha ng (bao gm c saccharose) t thc n thnh cc acid d dng ph hy men rng.

Saccharose, nh mt hydratecacbon tinh khit, cung cp nng lng 3,94 kilocalo trn

mt gam (hay 17 kilojoule trn gam). Khi mt lng ln thc phm cha nhiu saccharose c tiu th th cc thnh phn dinh dng c ch c th b loi ra khi thc n, v iu ny lm gia tng nguy c mc cc bnh kinh nin. Ngi ta khuyn co rng cc ung cha saccharose c th lin quan vi s pht trin ca bnh bo ph v khng insulin.

c) Ph gia

Acid citric:

Dng kt tinh khan hoc vi mt phn t nc.

Danh php IUPAC: Acid 2-hydroxypropan-1,2,3-tricacboxylic

Tn khc: Acid 3-hydroxypentanedioic acid 3-cacboxylic, Citrat hir, E330

Cng thc phn t: C6H8O7

Phn t gam: 192,123 g/mol (khan), 210,14 g/mol (monohydrat)

Tnh cht

T trng: 1,665 g/cm

im nng chy: 153 C

im si: phn hy 175 C

ha tan trong nc: 133 g/100 ml (20C)


Trang 22

acid (pKa): pKa1=3,15, pKa2=4,77, pKa3=6,40

Hnh 10: Acid Citric

Acid citric hay acid xitric l mt acid hu c yu, v l mt acid ba ln acid. N l mt cht bo qun t nhin v cng c s dng b sung v chua cho thc phm hay cc

loi nc ngt. N c k hiu l E330

nhit phng, acid citric l cht bt kt tinh mu trng. N c th tn ti di dng khan (khng cha nc) hay di dng ngm mt phn t nc (monohydrat). Dng khan kt tinh t nc nng, trong khi dng monohydrat hnh thnh khi acid citric kt tinh

t nc lnh. Dng monohydrat c th chuyn ha thnh dng khan khi nung nng ti

trn 74 C.

i vi cc dng nc gii kht th php o ngt tt nht l t l ng/acid. Gn

y, vic s dng cc thit b nhy hng ngoi cho php o c Brix (hm lng ng) v chua bng pht hin ng v acid citric thng qua cc dao ng phn t

c trng ca chng v iu ny cho php nh gi chnh xc hn ngt ca ung.

Acid citric c hu ht cc quc gia v t chc quc t cng nhn l an ton s dng trong thc phm. N hin din t nhin trong gn nh mi dng s sng, cc lng acid

citric d tha d dng trao i v bi tit ra khi c th. Tuy nhin, vic tip xc vi acid citric kh hay m c c th gy ra kch ng da v mt, v th bo h lao ng nn c s dng khi tip xc vi acid citric. Vic s dng qu nhiu acid citric cng d lm tn

hi men rng. Tip xc gn vi mt c th gy bng v lm mt th gic.

i khi hm lng qu cao acid citric c th gy tn hi cho tc, do n m lp cutin ca tc. N c th lm mt cc cht cn thit cho tc v lm tc b bc mu.

Ngoi chc nng to v, acid citric cn c tc dng c ch vi khun, nm si v nm men. i vi nhm vi khun gy bnh trong thc phm, th nghim ca Minor v Marth (1970) cho thy dung dch c chnh v pH 4,7 v 4,5 bng acid citric c kh nng c ch 90% v 99% s sinh trng ca t cu khun Staphylococcus aureus. Theo


Trang 23

Subramanian v Marth (1968), acid citric cng c tc dng km hm s pht trin ca Salmonella typhimurium.

Acid citric c ch s sinh trng ca nm si cng nh qu trnh sinh tng hp toxin nm si. Theo s liu nghin cu ca Reiss (1976), nng acid citric 0,75% khng nh

hng ng k n qu trnh sinh trng ca loi Aspergillus parasiticus, tuy nhin qu trnh sinh tng hp toxin b c ch hon ton. Cn i vi loi Aspergillus versicolor, nng acid citric 0,25% km hm ton b qu trnh sinh tng hp toxin si nm.

Acid citric c kh nng to phc (chelation) vi cc ion kim loi. Cc mui citrate canxi, kali v natri u ha tan tt trong nc v chng cng c kh nng c ch vi sinh vt.

Mu:

S dng cht mu t nhin.

Hng liu:

Hng chanh, o, mt ong

Vitamin C:

Bt hay tinh th mu trng hay hi vng, khng hi, v chua.

I.5. Ch tiu cht lng ca nguyn liu

I.5.1 Ch tiu cht lng ca l tr ti

Bng 9: Ch tiu ha l ca l tr ti

Tn ch tiu Mc hm lng

Hm lng cht ha tan 8%

Hm lng tannin, khng nh hn 9.0%

Hm lng cafein, khng nh hn 1.8%

Hm lng cht x, khng ln hn 16.5% Hm lng tro tng s 4 8%

Hm lng tp cht l 0.2%

Hm lng Fe 0.05%

I.5.2 Ch tiu ca nc

Ch tiu cm quan v ha l:


Trang 24

Bng 10: Cc ch tiu cm quan v ha l

Ch tiu vi sinh vt ca nc

a) Phi m bo cht lng khng gy ri ro cho sc kho ngi tiu dng (Khng

c c cc vi sinh vt gy bnh)

b) Ngoi ra phi tun th cc yu cu v vi sinh vt sau y


Trang 25

Bng 11 :Ch tiu vi sinh ca nc ung (quy nh s 80/778/EEC)\

Stt Ch tiu Th tch mu phn tch

Mc khuyn co

Mc cao nht cho php

Phng php

hp (s dng membrance

vi lc)

Phng php

MPN

1 Tng s vi khun hiu

kh

1000 10 cfu ( 37

oC)

100 cfu ( 27

oC)

2 Coliforms

tng s

100 0 MPN


Trang 26

- Hm lng tro 0.03 (%khi lng) Ch tiu cm quan:

Mu trng ng nh, tinh th ng u, kh, khng vn cc, khi ha tan trong nc c v ngt c trng, khng c v l, mi l, dung dch trong sut.

I.5.4. Ch tiu ca ph gia

Acid citric: Ch tiu ha hc:

Bng 12:Ch tiu ca acid citric dng trong thc phm (Rehm v cng s, 1996)

Tn ch tiu n v o Mc quy nh

Hm lng acid citric

Tro

Ch

Arsen

Sulphate

(%)

(%)

mg/kg

mg/kg

%

Khng thp hn 99,5

Khng vt qu 0,05

Khng vt qu 10

Khng vt qu 3

Khng pht hin

Ch tiu cm quan:

- Tinh th khng mu hay bt trng, khng vn cc. Dung dch trong nc ct 20g/l phi trong sut.

- V: chua, khng c v l.

- Mi: dung dch 20g/l phi khng c mi.

- Cu trc: ri v kh.

- Tp cht c hc: khng c c.


Trang 27

II. QUY

Quy trnh cng ngh dng s khi

Saccharose

Acid citric

Nc

Than hot tnh, bt tr lc

Nu syrup

Tr xanh

Dit men

V

Trch ly

Lc

Rt chai

Phi trnLm ngui

Lc

Ghp m

Tit trng

Sn phm

Tp cht

Ph gia

B

Chai PET

Nc


Trang 28

III A. QUY TRNH 1

1. Nu syrup

a) Mc ch

- Chun b: ng nht dch syrup thun tin cho qu trnh phi trn. Di tc

dng ca nhit m ng ha tan vo hn hp thnh phm mt cch tt nht. ng thi cc vi sinh vt ln trong nc ng ( nu c) s b tiu dit. c tc dng gii kht chng mt mi nhanh hn,.

- Ch bin: thu nhn hn hp ng nghch o.

b) Nhng bin i trong qu trnh nu syrup:

Bin i vt l: Nhit tng, tng p lc thm thu, tng nht, s thay i khi lng ring, t trng. Bin i ha hc:

- Tng hm lng cht kh. - Phn ng thy phn ng saccharose vi xc tc acid v nhit to thnh hn

hp ng glucose v fructose (c t l mol 1:1).

- S chuyn ha ng thnh syrup c thc hin qua phn ng sau:

C12H22O11 + H2O C6H12O6 + C6H12O6

- Phn ng caramel ha ng to cc hp cht sm mu.

Bin i ha l: - S ha tan ca ng saccharose vo nc di tc dng ca nhit. - S hp ph ca than hot tnh i vi cc tp cht hu c trong syrup, c bit l

cc hp cht mu.

Bin i v mt cm quan: - S thay i mu sc do phn ng caramel ha ng to cc hp cht sm mu. - S c mt ca acid trong nc ng cng tc dng ca nhit , nc l cc tc

nhn chuyn ha ng saccharose thnh ng nghch o lm tng v ngt, n nh ca sn phm cng tt hn

To> 80

oC

pH = 5,5- 6,5

Glucose Fructose


Trang 29

c) Thit b

ng

Bot tr loc

Than hoat tnh acid citric

Hi nc

Hnh 11:M hnh thit b nu syrup

Syrup ra


Trang 30

Hnh 12: Thit b nu syrup

Cu to thit b: - Thit b c dng hnh tr, y cu, c ch to bng thp khng r.

- Xung quanh phn thn di v y thit b c lp v o dng gia nhit bng hi.

- Nguyn liu s c np vo qua ca np trn np thit b. - Bn trong thit b c cnh khuy o trn nguyn liu, cnh khuy c truyn

ng bi motor t trn np thit b. - Sn phm c tho ra qua ca y thit b.

- Th tch s dng ca thit b thng l 75%.

Phng php thc hin

- Cho nc vo thit b v gia nhit nc n nhit 55 600C.

- Cho cnh khuy hot ng vi tc 30 50 vng/pht, ri cho ng v acid vo.

- Khi ng v acid ha tan hon ton vo nc, gia nhit hn hp n nhit 70 800C thc hin phn ng nghch o ng, thi gian khng ko di qu 2 gi.

- nhit 700C, thc hin qu trnh ty mu hn hp trong 20 30 pht, b sung c than hot tnh v bt tr lc vo ni nu syrup.

- Sau cng, gia nhit nhanh hn hp n si ri tin hnh lc v lm ngui syrup.


Trang 31

d) Thng s cng ngh:

- Nhit : 70 800C - Thi gian: khng qu 2 gi - Xc tc acid citric: 0.75% khi lng so vi ng saccharose.

Tiu chun cht lng syrup

- Trong sut, khng mu, khng mi l

- Hm lng ng trung bnh 65-70% - Lng ng chuyn ha > 90-95%

2. Lc: a) Mc ch: phn ring hn hp khng ng nht qua lp lc

- Tch tp cht - Ci thin trong dch syrup vi s h tr ca bt tr lc

b) Nhng bin i trong qu trnh lc:

- Bin i vt l: Khi lng ring hn hp gim, nhit gim. - Bin i ha l: Ch cn mt pha ng nht. - Bin i v mt cm quan: Tng trong.

c) Thit b: Thit b lc khung bn Cu to:

- Thit b lm vic gin on, huyn ph nhp vo lin tc, nc trong chy ra lin tc, cn tho b theo chu k

- Thit b lc khung bn c cu to ch yu bi khung v bn. - Khung gi vai tr cha b lc v l ni nhp huyn ph vo.

- Bn to ra b mt lc vi cc rnh dn nc lc. - Khung v bn thng c ch to c dng hnh vung v phi c s ghp kn

gia khung v bn. - Khung v bn c xp lin tip nhau trn gi . Gia khung v bn l vt ngn

lc.

Vt ngn lc th hin 3 tnh nng c bn: Gi pha rn cng nhiu cng tt, ng thi tr lc i vi pha lin tc

cng nh cng tt. S phn b ng u cc l xp (mao dn) trn b mt vch ngn lc. Chu c tc ng ca mi trng lc nh: thm t, bn v p

sut, nhit , ha hc, chy n, iu kin ti sinh b mt lc. Vch ngn lc c th c dng ht, si, tm, vt xp.

- p cht gia khung v bn bng c cu vt ai c c thc hin bi tay quay. - L dn huyn ph nhp liu ca khung v bn ni lin to thnh ng dn nh ra

ghp vi h thng cp liu. - Khi tin hnh lc, phi p cht khung v bn p sut lc khng lm dch lc r

r ra ngoi, v th thit b lc khung bn cn gi l thit b lc p.


Trang 32

Hnh 13: Cu to my p khung bn


Trang 33

Nguyn tc hot ng:

Hnh 14: M t nguyn tc hot ng ca thit b lc khung bn

- Huyn ph vo theo ng nhp liu sau phn ra theo s lng khung trn vo

khoang trng, di p sut nc lc i qua vch ngn lc theo cc rng trn bn chy xung v nh van c ly ra ngoi.

- B c gi trn b mt ca vt ngn lc v c cha trong khung.

- Khi b trong khung y th dng bm nc nng vo ra b nhm trch ly thm cht ha tan nhng hiu qu khng cao.

- Nn kh tch ht cht chit, x p, tho khung, tho b v sinh thit b

u im: - Thi gian lc: nhanh. - Lng nc ra: t. - m b: thp. - Din tch b mt lc ln.

- C th thay i nng sut bng cch thay i din tch lc. - Chi ph thp v bn.

Nhc im: - tn tht cht chit cao. - Thit b h nn khng p dng cho nhng thc phm d nhim vi sinh vt.

- Mc c gii ha v t ng ha: khng cao. - Thit b lm vic gin on nn tn thi gian cho vic tho b v ra b.


Trang 34

Hnh15 : Thit b lc khung bn dng trong quy m cng nghip

d) Thng s cng ngh:

p lc lc: 3at (c to ra bi bm nhp liu).

3. Lm ngui: a) Mc ch:

Chun b: h nhanh nhit dch nha, chun b cho qu trnh phi trn.

b) Nhng bin i trong qu trnh lm ngui syrup:

- Bin i vt l: nht hn hp tng, nhit gim. - Cc bin i khc khng ng k.

c) Thit b: Thit b trao i nhit dng bn mng Cu to


Trang 35

Hnh 16: Thit b trao i nhit dng bn mng .

y l loi thit b truyn nhit c b mt truyn nhit phng, to thnh t nhng tm bng ghp vo thnh nhng hp rng nhiu ngn, chng c nhng l ni nhau tng ng to thnh li chuyn ng ring cho tng lu cht. Gia cc tm bn c dng cc

tm m kn m bo ngn cch hai lu cht. Bn ngoi c h thng cc thanh ging c c vn p cht cc tm bn


Trang 36

Nguyn tc hot ng:

Hnh 17: M t ngyn tc hot ng ca thit b lm ngui

C mi giy, ng dn m ra cho lu cht chy vo. Gia mi cp a c mt ming m cao su, ngn cn lu cht ha ln vo nhau hoc r ra bn ngoi. V th, nhit c truyn t lu cht nng sang lu cht lnh qua cc a mng lm bng thp khng r.

u im:

- S dng vt liu mng nht cho b mt truyn nhit nn qu trnh truyn nhit t ti u.

- Ngoi ra, dng chy ri trong mi trng gip cho qu trnh i lu din ra thun li hn, dn n tng hiu qu truyn nhit gia cc mi trng.

- Nhng dng chy ri xut hin do b mt nhiu kha lm cn kh hnh thnh, u im ny ni bc so vi thit b truyn nhit dng ng lng ng

Nhc im: Khng lm vic di p sut cao v khng thch hp i vi cc nguyn liu dng nho v dng ht.(Nhng np gp trn a to nhng im ta gi cc cht dng bt nho v dng ht li . V th, gi cho thit b trao i nhit dng bn mng sch trc khi chy sn phm mi l iu v cng kh khn)


Trang 37

d) Thng s cng ngh:

Nhit : lm ngui n nhit 30-350C.

4. Dit men

a) Mc ch

Chun b:

- Trong ch bin ch xanh, khng cn to nn nhng bin i sinh ha cho tanin, nn enzyme khng c ch cho qu trnh ch bin. V vy ngay t giai on u ca qu

trnh ch bin ch xanh ngi ta phi dng nhit cao v hot enzyme c trong

nguyn liu khng to ra s bin i cc cht di tc dng ca enzyme. - Lm mm l ch to thun li cho giai on v tip theo

b) Nhng bin i trong qu trnh dit men

Bin i vt l: Lm thay i trng lng , th tch, cc tnh cht c hc chun b cho giai on v xon cnh ch.

Bin i ha sinh: Trong bp ch c 2 loi enzyme ch yu l: - Nhm enzyme thy phn : amilase, protease, glucosidase, - Nhm enzyme oxi ha kh : peroxidase, polyphenoloxidase,

Enzyme peroxidase, polyphenoloxidase ng vai tr quan trng nht v c tc dng khc nhau nhit cao hn s b v hot hon ton.

Bin i ha l: Cc cht mi d bay hi. V vy, mi gim mt t.

c) Thit b : Thit b dit men bng khng kh nng Cu to


Trang 38

Hnh 18: Thit b

Nguyn tc hot ng

2 - 3 kg/m2

120oC - 125

o0,45 - 1- 2

58 -

20- 25kg/m2

30 -

, nguy

do t hao ht cc cht tan hn.

d) Thng s cng ngh

- : 120oC - 125

oC

- : 1 - 2

- Thi gian lm ngui: 30 -


Trang 39

5. V a) Mc ch

Chun b:

To hnh xon cht cho cnh ch kt hp vi lm dp mt phn t bo ca l dch p

chit ra ngoi mt l to thun li cho qu trnh trch ly

b) Nhng bin i trong qu trnh v

Bin i vt l:

-S thay i v kch thc v hnh dng.

-Nhit tng do s c xt c hc ca khi tr vo thnh mng v v do qu trnh oxy ha trong khi tr v.

Bin i ha hc:

-Gim lng cht ha tan: gim lng tannin ha tan, gim lng nhm cht catechin.

-Gim nhiu lng chlorophyll.

-S thay i cc thnh phn khc: cc phc cht bay hi (benzaldehyde, n-pentanol), cc acid hu c, gim vitamin C ...

Cm quan: mu sc do s oxy ha tannin trong tr to nn cc cht mu nu v , gim lng chlorophyll.

c) Thit b :

Cu to

Hnh 19 : Thit b v tr


Trang 40

Thit b v tr thng c 3 b phn chnh: b phn ng lc, mm, thng cha nguyn liu v cc b phn ph tr khc. Trn b mt ca bn c nhng gn nhm tng tc dng v tr.

Nguyn tc hot ng

S dng lc ca my chuyn dng lm cho khi tr chuyn ng v t ma st vo nhau. Sau khi cho l tr vo my, khi ng my, mt tay quay s c quay di s iu khin ca motor, 2 tay quay cn li quay t do quanh trc ca n. Trc s sinh ra p

lc tc dng khi tr trong sut qu trnh v tr. p lc sinh ra do trc cng s lm cho cc cht lng trong l tr c thot ra ngoi, nh thc hin c qu trnh v tr.

d) Thng s cng ngh

Thi gian v mi m ko di khong 20 pht.

6. Trch ly:

Trch ly l qu trnh ho tan cht tan c trong tr vo dung mi thch hp. Dung mi thng dng trong trch ly tr l nuc. Nc l loi dung mi c nhiu u im: khng

c mi, khng c hi, khng gy chy n, r tin, d kim..

a) Mc ch:

Thu nhn cc cht chit (cc cht ha tan, mu, mi, ) t l tr.

b) Nhng bin i trong qu trnh trch ly:

Bin i vt l: - S khuch tn ca cc cht ha tan vo nc. - nht dung mi tng. Bin i ha hc: - iu kin nhit cao, tng tc ca acid amin v polyphenol to ra cc

aldehyde d bay hi, to hng thm cho tr. Cc acid amin nh alanin, phenylalanine, valin, leucine, isoleucine b gim i, trong khi hm lng cc aldehyde nh acetaldehyde, aldehyde butyric, aldehyde valeric tng ln

- Phn ng Maillard - acid amin phn ng vi cc ng kh to ra mu, mi ca nc tr trch ly.

Bin i ho l: C s chuyn pha

Nhng yu t nh hng n qu trnh trch ly:

- c tnh ca nguyn liu: Hnh dng, kch thc, cu trc mao qun ca nguyu liu. Hm m ca nguyn liu,hm m cng cao th qu trnh trch ly cng kh

khn. - c im ca thit b trch ly: Cu to, nguyn l vn hnh, - T l nguyn liu : dung mi phi ph hp. Dung mi qu nhiu s lm tn chi

ph nng lng, nu qu t th trch ly khng trit , tn thi gian trch ly.


Trang 41

- Nhit trch ly cng cao cng tt v nhit cao lm tng ho tan ca cc cu t vo dung mi lm gim nht v do tng h s khuyn tn v tng tc qu trnh trch ly.ng thi s dng nhit cao v hot enzyme v c ch vi sinh vt. Nhit cng l tc nhn xc tc cho cc phn ng oxy ha cc hp cht polyphenol, to gi tr cm quan cho sn phm. Tuy nhin nu nhit trch ly qu cao s gy mt mt cc

cu t mn cm vi nhit va c to thnh v ng thi lm tng ho tan ca cc cht khng mong mun vo dung dch.

- Ph thuc vo thi gian trch ly.

- S khuy o trong qu trnh trch ly.

c) Thit b: Thit b trch ly nhiu bc Cu to:

Thit b l mt h thng gm nhiu ni mc ni tip nhau.

Hnh 20: Thit b trch ly nhiu bc


Trang 42

Nguyn tc hot ng y l thit b hot ng gin on. Thng c t 3-5 ni chit. Gia cc ni thng lp t thm h thng gia nhit iu chnh nhit cho dng lu cht, hay s dng v cch nhit. L tr ti sau khi qua qu trnh v c np vo cc ni v nc nng s ln lt i qua

cc ni trch ly cht tan trong tr.

u tin, dung mi c np vo ni 1, t dch trch ly t ni 1 s i qua ni 2, qu

trnh c th tip din, khi qu trnh trch ly ni 4 kt thc, tho dch trch. B tr trong

cc ni c tho ra.

Nhit khi vo ni u tin khong 700C tng dn qua cc ni v khi n ni

cui cng nhit khong 900C.

d) Thng s cng ngh

- T l tr v dung mi: 1/10 - Nhit trch ly: 80 100oC.

- Nng dch trch: 5- 8%. 7. Lc

a) Mc ch:

- Chun b: cho qu trnh phi trn. - Hon thin: loi tp cht tinh sch v lm trong dch chit sau trch ly.

b) Nhng bin i ca nguyn liu trong qu trnh lc:

- C s thay i v mu sc do tp cht trong dch trch c tch ra, tng trong, c th loi b c mt s vi sinh vt c hi.

- Tn tht mt s cht nh: prtin kt ta,cht mu

- Trong lc khung bn c s tip xc vi khng kh, nu dit men khng tt s lm tn hao cc polyphenol trong tr (b oxi ha bi O2 )

Nhng yu t nh hng n qu trnh lc:

- B lc tr l loi nn p c, nn tnh cht b nh hng rt nhiu.

- Vic s dng than hot tnh hoc bt tr lc l bt buc . - Vt ngn lc c lm bng vt liu g. - Nhit lc - p sut lc

c) Thit b: thit b lc khung bn d) Thng s cng ngh:

p lc lc: 3at (c to ra bi bm nhp liu).


Trang 43

8. Phi trn a) Mc ch

Ch bin: Nhng thnh phn nguyn liu khc nhau bao gm: nc, syrup ng, dch chit t tr, ph gia s c phi trn theo mt t l xc nh to ra sn phm. .

b) Nhng bin i trong qu trnh phi trn:

Bin i vt l: S thay i v khi lng ring, th tch ca hn hp, cc ch tiu vt l nh: trong, khc x nh sng cng thay i, s bin i ca cc ch tiu

nhit l nh h s dn nhit, nhit dung, Bin i ha hc:

- Xy ra phn ng Maillard.

- pH ca hn hp gim. Bin i ha l: Tng nng cht kh (cht kh ca hn hp l tng cht kh ca

cc cu t so vi khi lng ca hn hp), tng ng nht cho sn phm Bin i v mt cm quan: Sau khi phi trn, sn phm c v hi ha, hng v c

trng. c) Thit b:

Hnh 21: Thit b phi trn

d) Thng s cng ngh:

- Nng syrup ng u vo: 65%.

- Nng ng u ra: 9- 11%.

- pH = 5.5-6

- Nhit phng.


Trang 44

9. Tit trng UHT a) Mc ch:

- Chun b: Cho qu trnh rt sn phm vo chai.

- Bo qun: un nng sn phm nhit cao c th tiu dit c vi sinh vt ko di thi gian bo qun cho sn phm.

b) Nhng bin i trong qu trnh gia nhit:

Bin i vt l: S thay i v th tch, khi lng, t trng (nc bc hi), nhit Bin i ha hc: Thay i tc cc phn ng ha hc (s oxy ha vitamin C, cc cht mu). Bin i ha l: ha tan tng, s bc hi nc, nht gim Bin i ha sinh: Enzym b v hot Bin i sinh hc: Tiu dit vi sinh vt trong sn phm. Bin i v mt cm quan: trong tng, mi c th gim do s bay hi ca mt s cu t hng.


Trang 45

c) Thit b tit trng UHT S dng thit b truyn nhit gin tip dng bn mng

Hnh 22: Thit b trao i nhit bng mng

Cu to:

Thit b trao i nhit dng bn mng c cu to bi nhiu a truyn nhit rt mng,

gp np, lm bng thp khng r gn cht vo nhau trong khung. Cc np gp gip cho a chng li s chnh lch p sut, tng din tch truyn nhit v to nn dng chy ri trong ng dn. C ln lt nh th , s chuyn ng ca dng chy ri mang li hiu sut truyn nhit cao, y chnh l u im ca thit b trao i nhit dng bn mng so vi thit b trao i nhit dng v - ng truyn thng


Trang 46

Nguyn tc hot ng: Ban u, dung dch s c gia nhit s b ln n 95

oC trong thit b trao i nhit

dng bng mng. Tip theo, phi trn dung dch v hi , ta s dng thit b phi trn hnh tr y cn. Nhit phi trn khong 140-150oC. Thi gian tit trng ko di trong vi giy. Sau , hn hp s c lm ngui v tch bt 1 phn nc trong thit b

chn khng. Ri thit b ny dung dch s gim nhit cn 80oC ri i vo thit b rt sn phm

Hinh 23: B phn lm ngui

d) Thng s k thut:

- Nhit tit trng : 140oC- 150 oC

- Thi gian phi trn hi: 2s


Trang 47

10. Rt chai, ng np: a) Mc ch:

- Bo qun: Rt nng hn ch s xm nhp ca vi sinh vt vo sn phm. - Hon thin: To s thun tin trong phn phi, lu kho, to hnh thc p hp dn ngi tiu dng.

b) Nhng bin i trong qu trnh rt chai, ng np:

Hu nh khng c bin i su sc no din ra. c) Thit b:

Hnh 24: Thit b chit rt chai PET t ng dng trn

Nguyn tc hot ng

Hn hp sau khi gia nhit c chit rt nng nhit 75-80oC vo chai nha, sau

tin hnh ng kn np.

Hn hp c bm t bn cha vo thit b rt vi h thng t ng, hn hp c rt

vo chai vi mt lng c nh v chnh xc. Sau khi rt, chai c ng np ngay.

Thng s cng ngh :

Nhit chit rt: 75-80oC


Trang 48

B. QUY TRNH 2

Trch ly: Thit b trch ly ngc chiu Cu to:

- Ca nhp liu cht rn v ca nhp liu dung mi.

- Ca tho liu cht rn v ca tho liu dch trch ly.

Hnh 25 : Thit b trch ly Kenedy

Nguyn tc hot ng

Nguyn liu i qua ca np liu u thit b, cn dung mi i vo ca np liu cui thit b. Nh chuyn ng xoay ca cc cnh qut t t u n cui thit b to ng

lc y nguyn liu di chuyn v pha cui thit b, cn dung mi th i v pha u thit

b theo ng dc xung .Trong qu trnh di chuyn, dung mi v nguyn liu tip xc vi nhau, qu trnh trch ly din ra. Nguyn liu sau khi tip xc vi dung mi v i v pha cui thn thit b th c thi b ra ngoi qua ca tho liu, cn dch trch ly th i v pha u thn thit b v chy vo bn cha.

Tc ca cnh qut c iu chnh nguyn liu lu li thit b trong mt khong thi gian cn thit v lu lng ca dung mi cng c iu chnh dch trch t c nng theo yu cu.

Thng s cng ngh:

- Thi gian lu ca nguyn liu: 0.5 2 gi. - Nhit dng dung mi: 80-900C. - Nng dch trch: 8 10%.


Trang 49

C. SO SNH HAI QUY TRNH CNG NGH

Quy trnh 1 (s dng thit

b trch ly nhiu bc cho

dng)

Quy trnh 2 (s dng thit

b trch ly ngc chiu)

Hiu sut Thp hn.

Cao hn, v dng dung mi

v dng nguyn liu chuyn ng ngc chiu nhau lm tng ng lc

qu trnh khuch tn.

Thit b Cng knh hn t cng knh hn

V sinh thit b Phc tp n gin (c th t v

sinh)

Tn tht cht dinh dng

Tn tht nhiu hn, do thi gian lu ca dch trch

trong thit b di hn t tn tht hn

Chi ph nng lng

Cao hn, v tn nhiu nng

lng gia nhit cho

dung mi hn. Thp hn

Tnh kinh t Thp hn Cao hn


Trang 50

IV. CH TIU SN PHM

Ch tiu vt l:

Sn phm dng lng

Ch tiu ha hc :

Hm lng carbohydrate 8-10g/100ml.

Hm lng natri: 2.5-3.5mg/100ml.

pH = 5.5-6.

Hm lng cht bo : 0 mg

Hm lng cht m : 0 mg

Hm lng tannin: 2.5mg/lt.

Hm lng caffein: 0.3mg/lt.

Sn phm cha 15-18 mg/100ml cht chng oxy ha t l tr xanh

Ch tiu ha l:

Sn phm ch c mt pha ng nht

Ch tiu sinh hc:

Gi tr nng lng: 34kcal/100ml.

Khng c vi sinh vt gy bnh: Samonella, E.coli, nm men, nm mc.

Ch tiu ha sinh :

Enzyme b hon ton v hot.

Ch tiu cm quan:

Mu: mu vng nht

Mi: hng tr (nu l tr xanh khng v chanh th c thm hng chanh)

V: ngt, cht, chua

Ch tiu bao b:

Chai phi kn, m bo cc yu t ca mi trng nh hi nc, bi bn, kh, vi

sinh vt khng xm nhp c vo trong thc phm.

Chai phi m bo khng b bin dng khi rt nng sn phm vo trong chai.

Chai c bao bc bng nhn in mu hn ch s nh hng ca nh sng n

sn phm.


Trang 51

V. THNH TU CNG NGH

1. Trch ly c h tr vi sng

c rt nhiu bo co v vic h tr vi sng trong qu trnh trch ly cc hp cht c

hot tnh sinh hc c ngun gc t thc vt (David T. Bailey, Parh L. Yuhasz, Bo Lin

Zheng, Method for isolation caffeine free catechins from green tea, US patent 6.210.679,

2001; David T. Bailey, Parh L. Yuhasz, Bo Lin Zheng, Method for isolation caffeine

free catechins from green tea, US patent 6.210.679, 2001 ; E.Surducan, Camellia

Neamtu, V. Surducan, Gabiela Nagy, S.Filip, Microwave power assisted sample

preparation, extraction studies, Studia Universitatis Babes-Bolyai, Physica, Special Issue,

2001).

Qu trnh trch ly c thc hin trong mt l vi sng trong nc (Whirpool oven,

cng sut 450, 600, 800 W). L tr ti c ct vi kch thc 1 1.5mm, sau ngm

trong nc (t l 1:5 n 1:15 g/ml) trong thi gian nht nh (10 30 pht), sau c

chuyn n bn cha, chnh pH ri a vo l vi sng. Qu trnh ngm trc khi trch ly

gip dung mi hp th hon ton vo nguyn liu tng hiu sut trch ly. Hiu sut trch

ly ch t 73.64% khi khng c qu trnh ngm v t 82.56% khi thi gian ngm l 30

pht. Vic bc x c iu chnh trong l vi sng theo chu k bnh thng (mt pht

bc x v hai pht ngng) gi nhit khng tng ln trn 80oC. Thi gian chiu x l

khong 6 pht. Sau ngng chiu x v bt u tin hnh trch ly. Qu trnh trch c

lp i lp li nhiu ln cho n khi nc trch ly hu nh khng thay i mu sc. Thi

gian trch khong 18 pht.

Hnh 26: Biu th hin kt qu trch ly bng vi sng


Trang 52

Nghin cu cho thy t l nguyn liu / dung mi khng c nhiu nh hng n sn

lng trch ly. C th s dng s lng dung mi ln t hiu sut trch ly cao hn, t

l cc cht khng mong mun cng b pha long (do nc l thnh phn chnh trong tr

xanh ng chai nn khng cn loi b dung mi).

Phng php trch ly c s h tr ca vi sng hu hiu hn phng php trch ly thng

thng v cht lng, thi gian v chi ph nng lng.

Bng 13: So snh kt qu ca vic trch ly c h tr vi sng v cc phng php khc

Phng

php

S tr gip ca vi

sng

Hon lu

nc nng

Khai thc nhit

phng

Thi gian

trch ly

6 pht

60 pht 24 gi

Catechins 16,90 (% trng

lng kh)

13,45

10,12


Trang 53

2. Trch ly tr c h tr siu m

Sng siu m lm xut hin cc bt kh nh. Cc bt kh ny khi bin mt s gy p sut

cc b lm tn thng mng t bo to iu kin cho cc cht ha tan khuch tn tt hn

vo dung mi. Ngoi ra cn c th gii thch c ch ca phng php ny da trn

nguyn l nn v ko. Sng siu m c bn cht l cc sng hnh sin c 2 na chu k m

v dng. Trong mi na chu k ca sng siu m s c hai s tc ng tri ngc nhau

ln cc phn t trn mng t bo nh l s nn v ko. Hai tc ng ny lm cho cc phn

t cng thng v b x nh ra.

Tr sau khi c ct nh khong 1- 1,5 mm c cho vo b ngm vi nc trong thi

gian 20-40 pht. Sau tin hnh x l trong b sng siu m (40W v 500 kHz) khong

15 pht. Tin hnh trch ly tr bng nc nhit 300C. Lp li qu trnh trch cho n

khi nc tr hu nh khng thay i v mu sc. Thi gian trch ly l 60 pht, tng ng

vi khong 3-4 ln trch.

3. Ging tr

Trong tr xanh c cha cc loi polyphenol c kh nng chng oxy ha, c li cho sc

khe con ngi nh catechin, anthoxanthin, anthoxyanne...Do qu trnh s n xut tr

xanh nn gi li cc cht ny. Nhng do trong qu trnh ch bin nhng cht ny thng

b oxy ha bi cc tc nhn oxy ha nh nh sng, nhit , oxy khng khV vy

ngi ta tin hnh nghin cu trn 5 ging tr LD97,PH1, HAT, LDP, TB14 t vng

Bo Lc, Lm ng tm ra ging tr cho sn lng cc cht trn l cao nht.

theo di qu trnh trch ly tr, caffeine v bn catechins c chn lm chun, thnh

phn ca chng c xc nh bng thang so mu HPLC. Trong th nghim, da vo

cc peak nh tnh v nh lng catechin (C), epicatechin (EC), epicatechin gallate

(ECG), epicagallocatechin gallate (EGCG) v caffeine.

s Cc kt qu cho thy tr HAT c lng catechin ( C / (C + ECG + EC + EGCG) =

20,49%) cao hn ca LD97, PH1, LDP1, TB14 (14.32%, 16.09%, 16.32% v 15.26%

tng ng). V vy, tr HAT nn c s dng lm nguyn liu cho khai thc.

Trong s bn hp cht catechin xc nh, phong ph nht l epigallocatechin gallate

(trong chim 80% tng s catechins trong HAT, PH1 v LDP1, 65% trong LD97 v

TB14), sau l epicatechin gallate (khong 12 - 18% ca tng s catechins) v

epicatechin (7 -12%). Caffeine c phn phi u gia cc nm ngun gc tr (t 2,5%

n 3,3%). Lng caffeine c th khng ph thuc vo ngun gc tr hoc iu kin ca

cc th nghim.


Trang 54

Bng 14: Phn tch thnh phn hp cht catechin v caffeine trong dch trch tr

Tea

breeds

Catechin

(% dried weight)

Caffeine

(%dried

weight) C EC EGCG ECG Total

LD97 0.87 1.78 9.11 2.56 14.32 2.8

PH1 0.39 0.93 12.85 1.92 16.09 3.3

HAT 0.19 1.52 16.30 2.48 20.49 3.2

LDP 0.08 1.03 13.57 1.63 16.32 2.5

TB14 0.41 1.94 10.09 2.82 15.26 3.1

( Phm Thnh Qun , Nguyn Hi H , Nguyn Xun , Trng Ngc Tuyn - i hc

Bch Khoa tp H Ch Minh ,Tng Vn Hng - i hc Quc T tp H Ch Minh)

4. Nghch o ng bng xc tc enzyme invertase

Sn xut ng nghch o bng phng php enzyme c mt s u im so vi s dng

xc tc l acid :

- iu kin phn ng n ha hn : cc ch phm invertase hin nay thng c nhit

ti thch dao ng trong khong 50 600C v pH ti thch nm trong vng acid

yu. iu ny s tit kim chi ph nng lng cho qu trnh sn xut v ngn nga hin tng syrup b sm mu.

- Cht lng syrup thu c s tt hn

Invertase c tn khoa hc l -D fructofuranosidefructrhydrolase vi m quc t

EC.3.3.3.26. Enzyme ny xc tc phn ng thy phn lin kt glycoside gia gc D-

glucose v D-fructose trong phn t ng saccharose. C ch xc tc ca enzyme

ny c kho st bi Reddy v Maley nh sau :

- u tin enzym invertase s to phc vi c cht saccharose thng qua trung tm hot ng ti v tr Glu-204 bng lin kt hydro.

- Tip theo gc fructose trong phn t saccharose s lin kt vi Asp-23 ca phn t enzym bng lin kt cng ha tr ti v tr C2 v lm cho lin kt glucoside gia glucose v fructose b ct t. Khi , phn t -D- glucose s nhn proton t Glu-204 v thot ra khi trung tm hot ng ca enzym.


Trang 55

- Cui cng l s cng nc vo phn t fructose v ct t lin kt cng ha tr gia fructose v Asp-23. Phn t fructose s tch ra khi trung tm hot ng ca enzyme.

quy m cng nghip, qu trnh nghch o ng bng invertase c thc hin bi

hai dng ch phm : enzyme ha tan v enzyme c nh. Enzyme c nh c s

dng trong thit b phn ng lin tc hoc c s dng nhiu ln trong thit b phn

ng gin on. Ngc li , enzyme t do thng ch c s dng mt ln trong thit

b phn ng gin on. Da trn c im ny, khi nim enzyme c nh bao gm

nhng trng hp sau :

- Enzyme ( dng ha tan) c gn vi cht mang ( dng khng tan ) to phc

enzyme-cht mang khng tan trong mi trng phn ng pha lng ( c cht v sn phm dng ha tan).

- Enzyme ( dng ha tan) c gn ln cht mang ( dng ha tan) tao phc enzyme- cht mang ha tan trong mi trng phn ng pha lng nhng s

dch chuyn ca phc enzyme-cht mang trong mi trng phn ng b hn

ch. - Enzyme ( dng ha tan) trong mi trng phn ng pha lng ( c cht v sn

phm dng ha tan) nhng v tr ca enzyme trong bnh phn ng b hn ch bi h thng membrane.

ng dng invertase c nh trong qu trnh nghch o saccharose theo phng php tnh:

c nh enzyme trong gel alginate. Hiu sut thy phn tng t chu k mt n chu k 4,

sau gim dn. hiu sut thy phn cao nht l 95% chu k 4 v thp nht l 73%

chu k 10. Mansour v cng s (2003) c nh invertase trn cht mang celite v

polyacrylamide. Kt qu thc nghim cho thy invertase c nh c th ti s dng n

20 chu k m hot tnh enzyme b gim i khng ng k. Tumturk v cng s (2000) khi

thy phn saccharose bng invertase c nh trn acid-co-alkyl polyamine, cc tc gi c

th ti s dng invertase c nh n 50 ln trong 5 ngy lin tip. ln s dng th 50,

hot tnh invertase c nh vn gi c 98% so vi gi tr ban u.

Quy trnh thy phn saccharose bng invertase c nh c thc hin tng t nh trong

trng hp s dng invertase t do. c im khc bit l sau mi chu k phn ng,

chng ta cn lc hn hp qua ry tch ch phm invertase c nh ra khi dung dch

phn ng. sau dung dich phn ng c a tr li ni nu syrup. Ngoi ra, vic un

si cn c tc dng v hot ngng phn t enzyme invertase b tch khi cht mang v b

ra tri vo dung dch phn ng trong qu trnh thy phn. Cui cung syrup c a qua

thit b lc khung bn tch cc tp cht khng tan cn st li ri c lm ngui trn

thit b trao bi nhit trc khi c bm vo bn bo qun.


Trang 56

i vi ch phm invertase c nh, sau khi c tch khi syrup , s c em x l

trc khi ti s dng cho m sn xut tip theo. Ty thuc vo bn cht ca cht mang v

phng php c nh m phng php s l s khc nhau. V d nh trong trng hp

invertase c nh trong gel alginate, u tin ngi ta s ngm cc ht gel c cha enzyme

tronng nc v khun c khuy o nh. Nhit ca nc ra l 2-40C. Khi , mt s

tp cht bm trn vng b mt ca ht gel s khuch tn vo nc. Cn ch l s khuy

o trong qu trnh ra cc ht gel cn phi c thc hin nh nhng, trnh lm v ht.

Thi gian ra ht ko di khong 15-30 pht. Sau qu trnh ra, cc ht gel cha invertase

c th c tip tc ti s dng ngay cho mt chu k sn xut mi. Trong mt s trng

hp, tng rn chc cho cc ht gel, ngi ta c th ngm ht trong dung dch CaCl2

2% trong thi gian vi gi.


Trang 57

TI LIU THAM KHO

[1]. KS. Bi Th t PGS.PTS. V Khc Nhng, K thut gieo trng v ch bin tr v c ph, Nh xut bn Nng nghip H Ni, 1999. [2]. L Bch Tuyt, Cc qu trnh cng ngh c bn trong sn xut thc phm, Nh xut bn gio dc, 1996. [3]. L Ngc T, Ho sinh cng nghip, Nh xut bn Khoa hc v K thut, H Ni, 2002.

[4]. Ng Hu Hp, Ha sinh ch, Nh xut bn i hc Bch Khoa, 1984. [5]. L Vn Vit Mn, Cng ngh sn xut cc sn phm t sa v thc ung, tp 1 : cng ngh sn xut cc sn phm t sa , Nh xut bn i Hc Quc gia thnh ph H Ch Minh, 2004

[6]. L Vn Vit Mn, Cng ngh sn xut cc sn phm t sa v thc ung, tp21 : cng ngh sn xut thc ung, Nh xut bn i Hc Quc gia thnh ph H Ch Minh, 2004.

[7]. V Vn Bang-V B Minh, Qu trnh v thit b cng ngh ha hc v thc phm, Tp 3: truyn khi, Nh xut bn i hc quc gia thnh ph H Ch Minh, 2001. [8]. Phm Vn Bn, Qu trnh v thit b truyn nhit Tp1, tp 2, Nh xut bn i hc quc gia thnh ph H Ch Minh, 2004.

[9]. Brennan J.G., Butter J.R., Cowell N.D., Lilley A.E.V., Food engineering operations

3rd

edition, Elsevier Applied Science, London & New York, 1990.

[10].George Di.Saravacos, Athanasios E.Kostaropoulos, Handbook of food processing

equipment, Kluwer Academic/Plenum Publishers, New York, 2002.

[11]. I.A.Khtrlava (dch: Ng Hu Hp Nguyn ng Vinh), K thut ch bin tr, Nh xut bn nng nghip H Ni, 1985. [12]. Malcolm J.W.Povey and Timothy J.Mason, Ultrasound in food processing, Blackie

academic & professional.

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