MC LC

iMC LC

iiDANH MC HNH

iiiDANH MC BNG

1CHNG 1:GII THIU

11.1t vn

11.2Mc tiu ca n

2CHNG 2:TNG QUAN V CY CH TI VIT NAM

22.1Ngun gc ra i ca cy ch

32.2c im sinh vt hc ca cy ch

32.2.1c im

52.2.2Phn loi thc vt

52.2.3Phn loi cy ch [1]

62.3c im ha sinh ca l ch

72.3.1Nc

82.3.2Hp cht phenol

102.3.3Alkaloid

102.3.4Protein v amino acid

102.3.5Lipid v acid bo

112.3.6Carbonhydrate

122.3.7Sc t

132.3.8Cht khong

132.3.9Enzyme

132.3.10Vitamin

142.3.11Hm lng tro

142.3.12Hp cht thm

142.4Gii thiu v cy ch ti Vit Nam

142.4.1S pht trin ca cy ch Vit Nam

152.4.2Cc vng trng ch Vit Nam

162.4.3Mt s ging ch Vit Nam

172.4.4Tnh hnh tiu th, xut khu ch Vit Nam

18CHNG 3:CNG NGH CH BIN CH

183.1Phn loi sn phm tr

183.1.1Phn loi theo mc ln men

183.1.2Phn loi theo hnh thi bn ngoi

183.1.3Phn loi tr theo hng p

183.1.4Cc loi tr c ung trong dn gian Vit Nam

203.2Thu hoch v bo qun ch

203.3Cng ngh ch bin mt s loi tr

203.3.1Tr xanh

233.3.2Tr en

37CHNG 4:CNG NGH CH BIN TR HA TAN

374.1Ngun gc

374.1.1Ngun gc chung

374.1.2Ti Vit Nam

374.2Cng ngh sn xut tr ha tan

374.2.1Tr ha tan dng bt

404.2.2Quy trnh sn xut tr ha tan

584.2.3Sn phm

604.3Cc sn phm tr ha tan trn th trng Vit Nam

624.4Thnh tu cng ngh mi

66TI LIU THAM KHO

DANH MC HNH

2Hnh 2.1 Cy ch

3Hnh 2.2 Sn lng ch cc quc gia nm 2007

3Hnh 2.3 Bp ch

4Hnh 2.4 Hoa ch

4Hnh 2.5 Qu ch

6Hnh 2.6 Thnh phn ha hc ca l ch ti

8Hnh 2.7 Tannin thy phn

8Hnh 2.8 Tannin ngng t

10Hnh 2.9 Cng thc cu to ca Caffeine

15Hnh 2.10 i ch

18Hnh 3.1 Mu sc nc tr

25Hnh 3.2 S hot ng mng kn khi dng kh i t di ln

25Hnh 3.3 S hot ng ca dng kh khi i t trn xung

27Hnh 3.4 Bn v (rolling table)

27Hnh 3.5 L ch c p xung trong khi bn v quay

28Hnh 3.6 L ch c xon li t t ng thi qu trnh ln men xy ra

30Hnh 3.7 Cc phn ng to cc theaflavins trong ln men ch en

32Hnh 3.8 S thay i ca tng hm lng cc cht mi v hm lng catechin trong cc giai on sn xut

33Hnh 3.9Cu to thit b ln men lin tc dng bng ti li

33Hnh 3.10 Thit b ln men lin tc

35Hnh 3.11 S nguyn l ca my sy bng ti

36Hnh 3.12 My sng phn loi

41Hnh 4.1 Thit b nghin a

41Hnh 4.2 Cu to cp a nghin

43Hnh 4.3 S trch ly tr nhiu bc

45Hnh 4.4 Khung v bn ca my lc p

45Hnh 4.5 My lc p khung bn

46Hnh 4.6 Qu trnh lc khung bn

46Hnh 4.7 S nguyn l thit b lc p khung bn

48Hnh 4.8 Thit b c c dng mng ri

- 49 -Hnh 4.9 Thit b bnh khuy trn bng cnh khuy

50Hnh 4.10 Thit b sy phun

52Hnh 4.11 S thit b sy thng hoa

54Hnh 4.12 Thit b to ht

55Hnh 4.13 Thit b trn vt ti nm ngang

55Hnh 4.14 Vt ti cnh xon lin tc lin trc

57Hnh 4.15 S nguyn tc nh lng thc phm

57Hnh 4.16 Thit b ng gi

58Hnh 4.17 Sn phm tr ha tan dng bt

59Hnh 4.18 Instant Green Tea Powder

59Hnh 4.19 Instant Black Tea Powder

60Hnh 4.20 Instant Oolong tea powder

60Hnh 4.21 Tr ha tan hng chanh

61Hnh 4.22 Tr chanh lipton ice tea

61Hnh 4.23 Nestea chanh

62Hnh 4.24 Tr ha tan Harris

DANH MC BNG7Bng 2.1 Thnh phn ha hc ca ch

11Bng 2.2 Hm lng lipid tng v acid bo tng cc giai on

12Bng 2.3 Hm lng pectin trong cc b phn khc nhau ca bp tr (tnh theo % cht kh)

13Bng 2.4 Hm lng vitamin C trong l ch ti

18Bng 3.1 nh gi cht lng ch nguyn liu

39Bng 4.1 Ch tin cm quan ca tr en bn thnh phm

39Bng 4.2 Ch tiu ho l ca tr en bn thnh phm

CHNG 1: GII THIU1.1 t vn

T xa n nay, tr l mt loi thc ung quen thuc i vi mi ngi, c bit l i vi ngi ng. Tr l sn phm l hay bp ca cy ch (Camellia sinensis) c lm kh. Dch trch thu c khi ngm tr trong nc nng gi l nc tr (hay nc ch). Tr c s dng trn ton th gii, v c xem l mt loi thc ung mang tnh ton cu. Do y l loi thc ung ph bin th hai trn th gii sau nc lc. Nc tr c hng thm c trng, v cht, hi ng nhng hu v ngt. Ung nc tr gip tng cng hot ng ca h thn kinh, gy hng phn, sng khoi, xua tan mt mi v sn phm c cha cc cht c hot tnh chng oxy ha.

Cng vi s pht trin khoa hc k thut, nhiu cng trnh nghin cu chng minh li ch ca tr. Bn cnh chc nng gii kht, tr c tc dng sinh l rt r rt i vi sc khe con ngi. Thnh phn caffeine v mt s alkaloid khc trong ch c tc dng kch thch h thn kinh trung ng, v i no lm cho tinh thn minh mn, gim mt nhc sau khi lao ng. Tr cn c tc dng phng v tr c nhiu loi bnh khc nhau, c bit l cc bnh v tim mch, ung th. Mt khc, tr l nt truyn thng ca nhiu dn tc, n mang mt gi tr v cng thing ling, cao qu trong i sng tinh thn ca con ngi.Ti nhiu nc pht trin nh Nht Bn, Singapore, i Loan, Malaysia,.. 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 ngh ra cch ch bin cc lai tr c th ung lin m khng cn qua cc cng on pha ch rm r. C hai loi tr ung lin mang tnh t ph trong phong cch dng tr l tr ti lc v tr ha tan.

Tr ha tan c xay thnh bt, tinh chit, lai b cht khng tan ri sy kh, tm p hng liu, cht bo qun, cht to vMi gi tr c khi lng t 10 20 g. Tr ho tan c dng bt ti xp, rt mn, gm nhng ht nh, mu vng nht (ch xanh), nu nht (ch en).Do trin vng pht trin th trng i vi mt hng tr ha tan, em thc hin n Tm hiu cng ngh sn xut tr ha tan c nhng hiu bit v cng ngh sn xut loi tr ny.1.2 Mc tiu ca n

Tm hiu v mt s loi tr ph bin trn th trng nh tr xanh, tr en v c bit l cng ngh sn xut tr ha tan ang c trn th trng v nhng hng i mi ca sn phm tr ha tan hin nay.

CHNG 2: TNG QUAN V CY CH TI VIT NAM

Hnh 2.1 Cy ch

2.1 Ngun gc ra i ca cy chTheo truyn thuyt th Vua Thn Nng khi i tun th phng nam, v tnh ung c mt th l cy ri trong ni nc ang si, lm cho tinh thn phn chn sng khoi nn ng gi l Tr. Mt huyn thoi khc k rng c t Ma S T ca Thin phi Thiu Lm T Trung Hoa, ng qun trong lc ta thin nn tc gin t ct m mt ca mnh qung xung t v ni y mc ln mt th cy k l, hi l nu nc ung khin cho tm hn tnh to, c gi l Tr.

Nm 1753, Cac Von Line (Carl Von Lenne), mt nh thc vt hc ngi Thy in nghin cu thu thp, phn loi cc mu ch Trung Quc, v ln u tin t tn khoa hc cy ch l Thea sinensis, phn thnh hai ging ch: Thea bohea (ch en) v Thea viridis (ch xanh), nh vy xc nhn Trung Quc l ni ra i ca cy ch.[6]Nm 1951. o Tha Trn (Trung Quc) a ra thuyt chit trung c nhiu hc gi th gii cng nhn. Theo thuyt ny, ci ni t nhin cy ch l khu vc gi ma ng Nam , v Lo, Mianma, Vn Nam v bc Vit Nam u c nhng cy ch hoang di. Cc iu kin v t ai, kh hu, lng ma ca c khu vc ny u rt ph hp vi s sinh trng ca cy ch, hp thnh mt vn ch nguyn thy. Hn na cc cy ch mc hoang di tm thy rt nhiu hc hai b cc con sng ln: Kim Sa Giang, Ph Long Giang, Salouen, Irravadi, M Kong, Bramapoutro... Cc con sng ny u bt ngun t dy ni cao nguyn Ty Tng. Cy ch di thc v pha ng qua tnh T Xuyn, b nh hng ca kh hu, nn bin thnh ging ch l nh, di thc v pha nam v ty nam n , Mianma, Annam (Vit Nam) bin thnh ging l to. [1]Nm 1974, Veckoven (J.Werkhoven, H Lan) chuyn vin ca t chc Lng thc th gii FAO, tng kt trong cun Cng ngh ch (Tp san Nng nghip 26, Rooma, 1974): Cy ch c Line xp loi v t tn l Thea sinensis (L.) c ngun gc vng ng Nam Trung Quc gn ngun sng Irrawadi (Mianma).[1] Hin nay ch c phn b kh rng trong nhng iu kin t nhin rt khc nhau, t 300 v nam n 450 v bc, l nhng ni c iu kin t nhin kh hu khc xa vng nguyn sn. Nhng thnh tu khoa hc ca cc nh chn ging Lin X (c), Trung Quc, Nht Bn, i Loan... to ra rt nhiu ging ch mi c kh nng thch ng vi cc iu kin kh hu khc nhau, to nhiu trin vng cho ngh trng ch trn th gii.

Hnh 2.2 Sn lng ch cc quc gia nm 20072.2 c im sinh vt hc ca cy ch

2.2.1 c im

2.2.1.1 Thn v cnh

Cy ch sinh trng trong iu kin t nhin l n trc, ngha l ch c mt thn chnh, trn phn ra cc cp cnh. Do c im sinh trng v do hnh dng phn cnh khc nhau, ngi ta chia thn ch ra lm ba loi: thn g, thn nh (thn bn g) v thn bi.

2.2.1.2 Mm ch

Trn cy ch c nhng loi mm: mm dinh dng v mm sinh thc. Mm dinh dng pht trin thnh cnh l, mm sinh thc pht trin thnh n hoa v qu.

2.2.1.3 Bp ch

Bp ch l on non ca mt cnh ch. Bp c hnh thnh t cc mm dinh dng, gm c tm (phn l non trn nh ca cnh cha xe ra) v hai hoc ba l non. Bp ch trong qu trnh sinh trng chu s chi phi ca nhiu yu t bn ngoi v yu t bn trong ca n. Kch thc ca bp thay i ty theo ging, loi v liu lng phn bn, cc khu k thut canh tc khc nh n, hi v iu kin a l ni trng trt.Bp ch l nguyn liu ch bin ra cc loi ch, v vy n quan h trc tip n nng sut v phm cht ca ch.

Hnh 2.3 Bp chBp ch gm c hai loi: bp bnh thng v bp m. Bp bnh thng (gm c tm v 2-3 l non). Bp m l bp pht trin khng bnh thng, trng lng bnh qun ca mt bp m thng bng khong 1/2 trng lng bp bnh thng v phm cht th thua km r rt. Nguyn nhn xut hin bp m rt phc tp. Mt mt do c im sinh vt hc ca cy trng, mt khc do nh hng xu ca cc iu kin bn ngoi hoc do bin php k thut khng thch hp.Bp ch hot ng sinh trng theo mt quy lut nht nh v hnh thnh nn cc t sinh trng theo th t thi gian. Thi gian ca mi t sinh trng ph thuc vo ging, ch dinh dng v iu kin kh hu. Trn mt cnh ch, mt nm c 4 5 t sinh trng ca bp.2.2.1.4 L ch

L ch mc trn cnh, mi t c mt l. L thng c nhiu thay i v hnh dng ty theo cc loi ging khc nhau v trong cc iu kin ngoi cnh khc nhau. L ch c gn rt r. Nhng gn chnh ca l ch thng khng pht trin ra n tn ra l. Ra l ch thng c rng ca, hnh dng rng ca trn l ch khc nhau ty theo ging. S i gn l l mt trong nhng ch tiu phn bit cc ging ch.2.2.1.5 R ch

Cy ch sng nhiu nm trn mt mnh t c nh, do vic nghin cu c im ca b r c ngha rt quan trng t c s cho cc bin php k thut trng trt. R ch pht trin tt to iu kin cho cc b phn trn mt t pht trin.H r ch gm c: r tr (r cc), r bn v r hp thu. R ch k vi, do yu cu t c phn ng chua. Canxi cn cho cy ch, n c mt nhng ni phn bo v sinh trng nh mt r, ngn cy, l thnh phn ca mng t bo v.v... 2.2.1.6 Hoa ch Hnh 2.4 Hoa chMu trng vi nhiu nh vng. Mi hoa gm 7 cnh v hng t nh di.2.2.1.7 Qu ch

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.

Hnh 2.5 Qu ch2.2.2 Phn loi thc vt

Ngnh Ngc lan Ht kn

B chThealesH chTheaceaeChichCamellia (Thea)LoiC.sinensisTn khoa hc: Camellia sinensis (L) (hay Thea sinensis L.)

(1935 Hi ngh Quc t v thc vt)

2.2.3 Phn loi cy ch [1]2.2.3.1 Ch Trung Quc ( China tea plant): Camellia sinensis (L)

Da vo kch thc l, Sealy (1958) phn bit 2 loi ca C.sinensis:

Ch Trung Quc l to (Camellia sinensis var. macrophylla):c im:- Thn g nh cao ti 5 m trong iu kin sinh trng t nhin.- L to chiu di trung bnh 4 14 cm, chiu rng 2 2.5 cm, mu xanh nht, bng, rng ca su khng u, u l nhn.- C trung bnh 8 9 i, gn l r.- Nng sut cao, phm cht tt.- Nguyn sn Vn Nam, T Xuyn (Trung Quc). Ch Trung Quc l nh (Camellia sinensis var. Bohea)c im:- Cy bi thp phn cnh nhiu.- L nh, dy nhiu gn sng, mu xanh m, l di 3,5 6,5 cm, rng 1 1.2 cm.- C 6 7 i gn l khng r, rng ca nh, khng u.- Bp nh, hoa nhiu, nng sut thp, phm cht bnh thng.- Kh nng chu rt nhit -12oC n -15oC.- Phn b ch yu min ng, ng nam Trung Quc, Nht Bn v mt s vng khc.2.2.3.2 Ch Assam ( Assam tea plant): Camellia assamica- Thn g cao 10 15 m, phn cnh tha.- L di 8 20 v rng 3,5 7,5 cm, mng v mm, thng c mu xanh m, l hnh bu dc, phin l gn sng, u l di.- C trung bnh 12 15 i gn l.

- Hoa mc n l hay thnh tng i, c 7 8 cnh mu trng hay i khi c m vng.

- S nh hoa tng t ca C.sinensis.

- Pht trin nhanh.

- Khng chu c rt hn, cn nhit cao.

- Nng sut, phm cht tt.

- Trng nhiu: n , Mianma, Vn Nam (Trung Quc) v mt s vng khc.

2.2.3.3 Ch Nam Indo (Indochina)- Nhm c bit ca Camellia assamica, gi l Camellia assamica sub sp.lasiocalys (Planch.MS)- Camellia assamica sub sp.lasiocalys (Planch.MS) hay loi ch ambodiensis/Southern l loi cy nh hnh chp, cao 6 10m, ngoi tr mt s cnh nm thng ng, hu ht nm cn bng nhau.

- L bng v c mu lam vng khi non, lam nh giai on trng thnh v chuyn sang mu lam hng hay hng vo cui ma.

- L c kch thc nm gia sinensis v assamica.2.2.3.4 Ch Shan (Camellia sinensis var. Shan)- Thn g, cao t 6 n 10 m.

- L to v di 15 18 cm mu xanh nht, u l di, rng ca nh v dy.

- Tm ch c nhiu lng t, trng v mn trng nh tuyt, nn cn gi l ch tuyt.

- C khong 10 i gn l.- C kh nng thch ng trong iu kin m m, a hnh cao, nng sut cao, phm cht thuc loi tt nht.- Nguyn sn Vn Nam - Trung Quc, min bc ca Min in v Vit Nam.2.3 c im ha sinh ca l ch

Hnh 2.6 Thnh phn ha hc ca l ch tiThnh phn ha hc ca ch tham gia trc tip vo s hnh thnh cht lng tr sn phm.

Bng 2.1 Thnh phn ha hc ca chThnh phn% khi lng cht kh

Polyphenol25 30

Epigallocatechin gallate8 12

Epicatechin gallate3 6

Epigallo catechin3 6

Epicatechin1 3

Catechin1 2

Gallocatechin3 4

Flavonols v flavonol glucosides3 4

Polyphenolic acids v depsides3 4

Leuco anthocyanins2 3

Chlorophylls v cc cht mu khc0,5 0,6

Khong5 6

Caffeine3 4

Theobromine0,2

Theophylline0,5

Amino acid4 5

Acid hu c0,5 0,6

Monosaccharide4 5

Polysaccharide14 22

Cellulose v hemicellulose4 7

Pectin5 6

Lignin5 6

Protein14 17

Lipid3 5

Cc hp cht bay hi0,01 0,02

2.3.1 Nc

L thnh phn ch yu trong bp ch.Vai tr:

Trong l tr, nc l mi trng xy ra s tc dng tng h gia cc cht ha tan chim t 75 80%. Ngoi ra, nc cn l thnh phn chnh tham gia vo cc phn ng thy phn v oxy ha kh xy ra khng ngng trong cc t bo ca l. Hm lng nc trong l ch gim dn t tm n cc l gi. Trong l ch nc tn ti 2 dng, nc t do v nc lin kt, nc cha ch yu trong cc kh qun ca l v l mi trng ha tan cc cht trong dch bo. Hm lng nc c quan h mt thit i vi qu trnh ch bin ch. Nu nguyn liu ch b mt nc qu nhanh th bin i sinh ha din ra nhanh v khng trit , i khi enzyme b c ch nu hm lng nc qu thp (< 10%). Nc trong nguyn liu ch nhiu hoc t u lm cho l ch b nt khi v. Trong qu trnh ch bin ch cn kim sot cht ch s bay hi nc (giai on lm ho, dit men).

2.3.2 Hp cht phenol

Tannin

Tanin l hp cht quan trng trong l ch, n c tnh cht quyt nh n mu sc nc pha, hng thm v v cht ca ch. Tanin thng c 2 loi: tannin ngng t v thy phn.Tannin thy phn: trung tm ca phn t tannin c cha 1 phn t polyol carbohydrate (thng l D-glucose). Nhm hydroxy ca carbohydrate c ester ha mt phn hoc hon ton vi nhm phenolic nh acid gallic (trong gallotannin) hay acid ellagic (trong ellagitannin). Cc tannin ny s b thy phn khi tc dng vi acid yu hay base yu to thnh carbohydrate v acid phenolic. Acid gallic

Tannin thy phn

Hnh 2.7 Tannin thy phnTannin ngng t: hay cn gi l proanthocyanidin, l polymer ca 2 n 50 cc phn t flavonoid. Cc phn t ny kt hp vi nhau bng cc lin kt C C, v cc lin kt ny khng b thy phn.

Hnh 2.8 Tannin ngng t

Tannin trong ch thng l tannin ngng t. Cht tiu biu cho tannin ngng t l catechin bao gm catechin v gallo-catechin (tannin thy phn tc dng vi FeCl3 cho mu xanh da tri cn tannin ngng t cho mu xanh en). Khi b tc dng ca acid long, tannin ngng t khng b thy phn thnh cc phn t n gin v ngc li n ngng t vi nhau thnh tannin (hay flobafen).

Ch cng non th hm lng tannin cng cao. Cht tanin trong tr cng nhiu th phm cht tr cng cao. Lng tanin phn b khng ng u trn cng mt bp tr, tp trung nhiu nht tm (39.9%), ri n l non (l mt 36,8%; l hai 36,1%; l ba 29,25%; cung gi 25%, l bnh t, l gi Cht tanin c kh nng kt hp vi Albumin to thnh cht khng ha tan. Tnh cht ny quan trng i vi qu trnh ch bin tr. Tanin kt hp vi caffeine thnh cht khng ho tan ng vng trn mt nc khi nc ch ngui. Tc dng ca tannin ch nh sau:

+ i vi cy ch, iu tit cc qu trnh oxi ha kh trong cy ch, nng cao tnh khng ca cy ch i vi su bnh hi ch.

+ i vi cng ngh ch, nu khng b oxi ha th sn phm l ch xanh, nu b oxi ha di tc dng ca enzyme th sn phm l ch en, ch vng ty mc oxi ha. Hm lng tannin cao th cht lng tt, nhng phi c t l thch ng gia cc hot cht trong ch.

+ i vi c th con ngi, tannin c tc dng cm mu, tng cng sc khng ca cc thnh huyt qun trong c th ng vt, tng cng s ng ha v s tch ly vitamin CCatechin

6 catechin trong ch bao gm:Catechin (C)

Epicatechin (EC)

Epicatechin gallate (ECG)

Gallocatechin (GC)Epigallocatechin gallate (EGCG)

Epigallocatechin (EGC)

Cc " epi" c cu trc ging nh cc catechin, nhng khc nhau v s nh hng trong khng gian, dn n tnh cht ha hc s khc nhau.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. Cc catechin b oxy ha bi enzyme polyphenol oxidase, u tin s hnh thnh hp cht gi l orthoquinones, cc orthoquinone khng bn s chuyn ha thnh theaflavin (TF), cc TF ny khi phn ng ngng t to thnh thearubigin (TR).2.3.3 Alkaloid

Alkaloid chnh ca ch l Caffeine, c tc dng dc l, to cm gic hng phn cho ngi ung. Caffeine l mt dn xut ca purine, c cu trc 1,3,7-tri-methyl xanthine. Hm lng caffeine trong ch chim khong 2,5 5,5% trng lng kh trong l ch ti. Caffeine trong sn xut do qu trnh ln men phn ng vi cc sn phm oxi ha ca catechin to ra tanat-caffeine c mi thm v v d chu. Khi pha nc, hp cht tanat caffein b kt ta khi nc ch ngui v to thnh vng ch (creamy).Ch cng non, hm lng caffeine cng cao. Trong qu trnh ch bin, hm lng caffeine trong l khng b bin i, ch thay i trong mt gii hn nh.

Hnh 2.9 Cng thc cu to ca Caffeine2.3.4 Protein v amino acidProtein l mt trong cc nhm cht ch yu v quan trng trong thnh phn ca l ch. Protein trong bp ch phn b khng ng u, chim khong 15% tng lng cht kh ca l ch ti. Trong qu trnh ch bin ch, protein l ngun cung cp cc acid amin t do v mt phn protein b phn gii bi cc enzyme 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 ch. Trong sn xut tr xanh, hm lng protein cao gip lm p b mt ch, nhng trong sn xut tr en, hm lng protein cao th hm lng tannin th c th nh hng xu n v ca sn phm v trong qu trnh ch bin ch, c bit l trong qu trnh ln men, protein kt hp vi tannin v n chuyn thnh hp cht khng tan, lm gim lng tannin ha tan.

L ch cng non hm lng protein cng cao.Cc aminoacid trong ch khng nhiu, thng khong t 0,2 0,3% cht kh, n c tc dng tt i vi cht lng ca ch en v ch xanh.2.3.5 Lipid v acid bo

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 tnh cht gi mi 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, Hm lng phospholipid v thnh phn cc acid bo rt khc nhau cc chng loi, cc giai on sn xut.Bng 2.2 Hm lng lipid tng v acid bo tng cc giai on Cc giai onHm lng lipid tng

(%)Hm lng acid bo tng (g/g)

Ch ti6,59,8

Lm ho5,78,4

V4,56,6

Ln men4,34,8

Ch en thnh phm2,83,7

Thnh phn acid bo ch yu trong ch l linolenic, linoleic, oleic v palmitic.

2.3.6 CarbonhydrateL ch cha hu ht cc loi ng nh: glucose, fructose, galactose, maltose, citose, arabinose, ribose, Hm lng monose trong l ch ch chim 1 2% v saccharose chim t 0,5 2,5%. Trong khi , hm lng cc polysaccharide trong l ch ln n 10 12% v cao hn na. Lng tinh bt, cellulose v hemicellulose cng tng theo mc trng thnh ca l ch. Nh vy, nguyn liu cng gi, cht lng ca n cng km. Do , hm lng hydratcarbon trong l ch cng cao (ch yu cha cc polysaccharide khng tan) th cht lng tr cng thp.Tuy nhin, cc ng ha tan trong l ch 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 ch 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.Ta thy, l cng gi th lng ng kh v sacharose cng nh tng lng ng ha tan cng ln.

Thnh t bo ca l c cu to cellulose c bao xung quanh bi hemicellulose v lignin, ngn chn s xm nhp ca enzyme thy phn. bp trng thnh, tnh cht mng nc gim i l do s lin kt cu trc gia cc thnh phn phenolic ca lignin, polysacharide v cutin ca thnh t bo.Hp cht pectin thuc nhm hydratcarbon v l hn hp phc tp ca poly saccharide 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 non th cha nhiu pectin tan trong nc nhng tng pectin th t so vi l tr gi, c bit trong cung tr rt giu pectin.Bng 2.3 Hm lng pectin trong cc b phn khc nhau ca bp tr (tnh theo % cht kh)

Nhm cht pectinTm v

l th nhtL th haiL th baCung tr

Ha tan trong nc2,852,101,832,37

Ha tan trong acid oxalic5,106,316,517,11

Ha tan trong amino oxalat5,427,067,948,34

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, hng thm ca tr thnh phm. Trong qu trnh sy, pectin c tc dng c nh cc thnh phn cht tan trn b mt l ch. 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.

Hm lng pectin kh cao, thng t 11 17% so vi lng cht kh trong l ch ti, v ch cng gi th hm lng pectin cng cao. Ring i vi pectin tan trong nc, ch cng non hm lng cng cao.2.3.7 Sc tC 3 nhm sc t chnh c tm thy l chlorophylls, anthocyanidins, carotenoids.Chlorophylls:

Cht mu u tin c xt ti l chlorophylls. Nh c chlorophys m l ch c mu xanh lc. Chlorophylls 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. Chlorophylls chnh l hn hp ca hai cht gn ging nhau v thnh phn cu trc v cu trc l Chlorophylls a- C55H72O5N4Mg (mu xanh lam) v Chlorophylls b- C55H70O5N4Mg (mu xanh vng). Khi un nng, Mg s tch khi phn t Chlorophylls v hydro s c thay th vo. Do , ta s thu c cht khc gi l feofitin a v feofitin b v dung dch lc ny s c mu vng xm.

Hm lng Chlorophylls trong l ch nh hng xu n cht lng ca ch.

Hm lng Chlorophylls c tng ln cng vi cc loi ch th. Ch cng c phm cht thp th hm lng Chlorophylls cng cao, cn trong cung ch th hm lng ny hu nh t nht. V vy, cung ch c phm cht tng i tt.

Anthocyanidins:

Delphenidin v cyanidin l thnh phn anthocyanidin chnh c tm thy trong l ch.

Trong tr xanh: lm xu mu nc tr, lm tng v ng.

Vai tr ca anthocyanidins trong cht lng ca tr en l vn cha c ch r.

Carotenoids:

C 14 loi c tm thy trong l ch. Nhng thnh phn chnh: Xanthophylls, -carotene, violaxanthine v neoxanthine.

Hm lng ca c 4 carotenoid trn gim ng k trong sut qu trnh sn xut tr en. V d: neoxanthine phn hy to -darmascenone v cung cp ng k cho hng thm ca tr. Ch CTC tn tht carotenoid nhiu hn ch OTD.

2.3.8 Cht khongCh cha khong 5% khong. Thnh phn chnh: kali (50%). Mt vi l ch cha fluorine vi hm lng cao (0,015 0,03%).

2.3.9 EnzymeL nhn t quan trng trong qu trnh sinh trng v ch bin ch, c bit trong ch bin ch en. Enzyme c vai tr quyt nh chiu hng bin i cc phn ng sinh ha trong giai on lm ho, v, ln men. Trong bp ch c 2 loi enzyme ch yu l:

- Nhm enzyme thy phn:amylase, protease, glucosidase,

- Nhm enzyme oxi ha kh: peroxydase (PO), polyphenoloxydase (PPO)Ta s tm hiu r v mt s loi enzyme c trong ch:

Polyphenol oxydase: hin din trong t bo biu b ca l

5 Dehydroshikimate reductase: l enzyme chnh trong qu trnh sinh tng hp cc hp cht phenol thng qua con ng phenylalanine.

Phenylalanine ammonia-lyase: xc tc cho qu trnh phn tch ca phenylalanine thnh trans-cinnamate v NH3, ng vai tr quan trng cho qu trnh sinh tng hp phenols. Hot tnh ca chng trong l ch tng thch vi hm lng ca catechins v epicatechins.

Proteinases: to qu trnh thy phn protein trong qu trnh lm ho, lm tng hm lng peptides v acid amine t do

Chlorophyllases tham gia vo qu trnh phn hy chlorophyll, transaminases trong qu trnh to cc thnh phn to mi.

Pectin methylesterase: qu trnh demethylation ca pectin, to thnh gel acid pectic, nh hng ln thm ca mng membrane t bo, lm gim s khuch tn oxy vo l trong qu trnh ln men. 2.3.10 VitaminNhm vitamin khng ha tan trong nc c trong l ch l A, D, E, F, K Trong th vitamin K (liu lng 300 500 n v sinh l trong 1g ch) chim t l ln, loi vitamin ny c kh nng lm mu ng t.

Nhm vitamin ha tan trong nc l B, PP, C,Trong nhm vitamin B, c th l vitamin B1 (tiamin) v vitamin PP (acid nicotinic), vitamin B2 (riboflavin) v acid pantotenic. Ngoi ra, trong l ch, lng vitamin C (acid ascorbic) cng c rt nhiu nhng hm lng cc phn khc nhau ca bp ch cng khng ging nhau. Trong thi gian ch bin ch en, hm lng acid ascorbic gim i ng k do qu trnh oxy ha trong qu trnh v ch v ln men ch v b phn hy trong qu trnh sy kh ch. Cn trong qu trnh ch bin ch xanh vitamin C t b ph hy hn. Bng 2.4 Hm lng vitamin C trong l ch ti

LTmL 1L 2L 3L gi

mg/kg cht kh7,039,9910,447,883,83

2.3.11 Hm lng tro

Thnh phn tro ca l tr ti dao ng t 4 7%. 2.3.12 Hp cht thm

Cc cht thm l mt hn hp cc cht bay hi tp trung trong cc c quan ca cy ch. Cht thm ny c hnh thnh trong qu trnh sinh trng pht dc cy ch v c trong qu trnh ch bin ch.

Hng thm l mt ch tiu quan trng nht trong nh gi cht lng ch, v 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 sn phm ca s chuyn ha acid amin khi kt hp vi catechin di tc dng ca polyphenoloxydase.

Cc cht c tnh hp ph v gi mi.

nh hng ca nhit cao khi pha ch

Ngoi ra, cn do cc bin php p hng v phun hng nhn to cho ch.

Theo ti liu ca nhiu tc gi, trong ch ti v ch thnh phm c cha cc cu t thm sau:

Nhm cc acid hu c gm cc acid: acetic, propionic, salicilic, n-butyric, isobutyric, isovalerianic, capronic, caprilic, hexenic panmitinic, phenylacetic, benzoic,

Nhm ru gm c: isoamylic, isobutylic, n-butylic, hexanol, n-octanol, pentanol, benzilic, benzyletylic, isopentanol, metyletyletanol, phenyletanol, metylbutanol, acetylpirol,

Nhm aldehyd gm c: n- v iso-butaral, n-valerianal, metylacetal, hexenal, benzal, vanilin, paraoxybenzealaldehyd,

Nhm cc hp cht khc gm: phenol, cresol, geraniol, linalol, citral, citronelol, tecpineol, acetonphenol, metylacetat, acrolein, metylsalicilat,

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.

2.4 Gii thiu v cy ch ti Vit Nam

2.4.1 S pht trin ca cy ch Vit Nam

Vit Nam, tc ung tr c t rt lu i. Ngi Vit Nam bit n tr sm hn nhiu so vi cc nc. Theo mt ti liu kho cu ca y ban khoa hc x hi th ngi ta tm thy nhng du tch ca l v cy ch ha thch vng t t Hng Vng (Ph Th). Xa hn na, h cn nghi ng cy ch c t thi k sn vi (vn ha Ha Bnh). Cho n nay, vng Sui Ging (Vn Chn - Ngha L - Yn Bi), trn cao 1.000 m so vi mt bin, c mt rng ch hoang khong 40000 cy ch di, trong c mt cy ch c th ln nht, ba ngi m khng xu. pha nam, cy ch xut hin u tin Lm ng vo nm 1927 ti Cu t ( Lt). Sau theo qu trnh hnh thnh v pht trin, n c mt ti Di Linh v Bo Lc sau nm 1930 bt u t nhng n in ca ngi Php nh: Felit Blao, Blao Sierr Lm ng l mt tnh nm Nam Ty Nguyn, vi phn ln din tch l t bazan phn b ch yu cao t hn 800 1600 m so vi mc nc bin, nhit 18 220C, lng ma trung bnh hng nm 1800 2600 mm, l iu kin thch hp pht trin cy tr, c bit l tr Oolong. Kh hu v th nhng l hai yu t quan trng nht cho cy tr pht huy ti u v cht lng. Ngy nay cy ch rt ph bin v tr thnh mt thc ung khng th thiu ca rt nhiu gia nh ngi Vit.

Hnh 2.10 i ch

2.4.2 Cc vng trng ch Vit Nam

Vit Nam nm trong vng gi ma ng Nam , ci ni ca cy ch.

- Kh hu t ai rt thch hp vi sinh trng cy ch. Lng nc ma di do 1700-2000 mm/nm. Nhit 21 22,6 0C, m khng kh 80 85%. t ai trng ch gm 2 loi phin thch st v bazan mu m.

- Ch trng v tuyn B 11,5 22,50C; chia thnh 3 vng: vng thp di 300 m, vng gia 300 600 m, vng cao t 600 n trn 1000 m, nn cht lng ch rt tt.

- Ging ch bn a gm 2 ging Trung Du v Shan, lm c ch xanh v ch en; c bit ging ch Shan min ni c bp nhiu lng tuyt trng, c th trng quc t rt a chung. Ngoi ra cn nhng ging ch tt lm ch en, ch xanh, ch long, nhp ni ca Trung Quc, i Loan, Nht Bn, n v Srilanka, Innxia.Do iu kin t ai v kh hu thch hp cho nn cy ch c trng trt ri rc hu ht cc tnh trung du v min ni nc ta, nhng tp trung mt s vng chnh nh sau: Vng ch min ni: gm cc tnh H Tuyn, Hong Lin Sn, Sn La, ging ch c trng ch yu vng ny l ch Shan (cn gi l ch tuyt) c nng sut cao, phm cht tt. Sn lng ch ca vng ny chim 25 - 30% tng sn lng ch ca min Bc. Trong tng lai s nng t trng sn lng ln 50 - 60%. Sn phm ch yu ca vng ch min ni l ch lc, ch mn. Hin nay sn xut ch xanh chim u th. Vng ch trung du: gm cc tnh Vnh Ph, H Bc, H Sn Bnh, Bc Thi v mt phn ca Hong Lin Sn (Yn Bi c). L vng sn xut ch ch yu, chim 70% sn lng ch ca min Bc. Ging ch chnh c trng trt l ging Trung du (Trung Quc l to) c nng sut cao v phm cht tt. Sn phm ch yu l ch en v ch xanh tiu dng v xut khu. Vng ch ti: gm cc tnh ng bng Bc b v khu 4 c, vng ny nhn dn c tp qun s dng l bnh t ung ti (khng qua qu trnh ch bin). Nm 1972 din tch vng ch ti l 8098 ha, ch c trng ch yu cc tnh Ngh Tnh (4550 ha), Thanh Ha (1427 ha). Nhng nm gn y mt s vn ch ti c chm sc, n hi chuyn sang ch hi bp. Hin nay vng ch ny ang gi v tr quan trng trong vic gii quyt nhu cu thc ung ca nhn dn. min Nam ch c trng ch yu hai tnh Lm ng v Gia Lai - Cng Tum. Vng nam Ty Nguyn (Lm ng) l vng cao nguyn nhit i, cao 800 - 1500 m, thch hp vi ging ch Shan. Vng bc Ty Nguyn thp hn (500 - 700m), kh hu thch hp vi cc ging ch Atxam v Trung du. Din tch trng ch ca cc tnh pha nam hin c khong 8200 ha (din tch trng ch t c cao nht nm 1965 l 9685 ha vi tng sn lng l 5905 tn ch kh).Kt qu bc u ca vic iu tra quy hoch cho thy kh nng pht trin mt s vng ch tp trung nh sau:

+ H Tuyn: 10000 12000 ha t trng ch, ch yu cc huyn V Xuyn, Bc Quang, Yn Sn, Sn Dng.

+ Bc Thi: 5000 7000 ha, tp trung cc huyn i T, Ph Lng, nh Ha, ng H.

+ Vnh Ph: khong 10000 ha, ch yu cc huyn Sng L, Sng Thao, Thanh Sn.

+ Hong Lin Sn: 12000 - 15000 ha, tp trung cc huyn Vn Chn, Trn Yn.

+ Ngh Tnh: 8000 ha, ch yu cc huyn Thanh Chng, Anh Sn, Ngha n, Hng Sn, Hng Kh.

+ Thanh Ha: 2800 3000 ha, tp trung nhiu Nh Xun.

+ Bnh Tr Thin: khong 2200 2500 ha

+ Lm ng: kh nng pht trin trn 20000ha, ch yu Bo Lc, Di Linh.+ Gia Lai Cng Tum cng c trn 10000 ha.

2.4.3 Mt s ging ch Vit Nam

2.4.3.1 Camellia sinensis var. macrophylla

Tn khoa hc: Camellia sinensis var. macrophyllaTrng cc tnh trung du

Tn gi ty theo mu sc ca l: Trung du l xanh, trung du l vng,

T l trng cc ging tr trung du min Bc t ti 70%

Nng sut bp trong sn xut i tr khi tr 5-19 tui thng t 4-5 tn/ha

c tnh: chu c t xu, nhng nhiu su hi: ry xanh, b cnh t, vng cao thng b bnh phng l.

Ch Trung du thng ch bin ch xanh, ch en u cho phm cht tt.

S ln thu hoch trong nm: vng tr sinh trng tt thu hoch 25 30 ln/nm2.4.3.2 Camellisa sinensis var. Shan

Tn khoa hc: Camellisa sinensis var. ShanTrng min ni cc tnh min bc v min nam Ty Nguyn (Lm ng)

Tn gi theo a phng: Shan Mc Chu, Shan Tham V, Shan Trn Ninh

Nng sut bp thng t 6 7 tn/ha.

Bp ch c nhiu tuyt, dng ch bin tr xanh.

S ln thu hoch trong nm: vng tr sinh trng tt thu hoch 25 30 ln/nm2.4.4 Tnh hnh tiu th, xut khu ch Vit Nam

Theo Hip hi Ch Vit Nam, trong ba thng u nm 2011. Vit Nam xut khu c 26000 tn ch tr gi 36 triu USD. Gi tr t gn mc cng k nm ngoi trc s gia tng 3,7% v gi c xut khu, mc gi trung bnh 1437 USD/tn. Nm 2011 vi nhu cu tiu th cao t pha khch hng, cng vi li th v gi, Hip hi Ch d bo kim ngch xut khu nm 2011 s tip tc tng khong 20% so vi mc 197 triu USD ca nm 2010, ln trn 200 triu USD. V khi lng xut khu, c th n nh quanh mc 135 nghn tn ca nm 2010.Hin nc ta l nc c sn lng ch ng th 5 th gii v xut khu ra khong 110 nc. Ba th trng ln l Pakixtan, i Loan v Nga.Hin nay, ch en vn l mt hng ch xut khu ch yu ca nc ta (chim hn 60% tng gi tr xut khu), i vi loi sn phm ny th i Loan l th trng ln nht, chim 17%, tip n l Nga, Irc, Pakistan, c v Singapore.. Xut khu ch en trong thng 1/2011 t 10,26 triu USD, gim 25% so vi thng trc v gim 47,02% so vi cng k thng 1/2010,Vit Nam l quc gia sn xut v xut khu ch ln th 5 th gii ch sau n , Trung Quc, Kenya, Sri Lanka v ngang hng vi Indonesia.Theo B Nng nghip v Pht trin nng thn, xut khu ch thng 3/2010 t 7000 tn, kim ngch 9 triu USD, a lng ch xut khu c qu 1 ln 24000 tn, kim ngch 33 triu USD. Trong qu 1, mt s th trng xut khu ch ca Vit Nam l Nga, Pakistan, n , i Loan, tiu vng quc rp,...CHNG 3: CNG NGH CH BIN CHPhn loi theo hm lng bnh t: TCVN 1053 86

Bng 3.1 nh gi cht lng ch nguyn liu

Loi chLoi bp% Bnh t

A1 tm v 2 3 l non

B1 tm v 2 3 l non

C1 tm v 2 3 l non

D1 tm v 2 3 l non

3.1 Phn loi sn phm tr

3.1.1 Phn loi theo mc ln men

Khng ln men: tr xanh

Ln men mt phn: tr vng v tr

Ln men hon ton: tr en

Hnh 3.1 Mu sc nc tr3.1.2 Phn loi theo hnh thi bn ngoi

Tr ri

Tr bnh

Tr bt hoc cao tr

3.1.3 Phn loi tr theo hng p

Tr x: khng hng p

Tr hng: hng hoa ti hoc hng liu kh p hng

3.1.4 Cc loi tr c ung trong dn gian Vit Nam

3.1.4.1 Tr ti

Nguyn liu gm l ch non v gi, to nh, xanh ti, khng qua ch bin, hi v ra sch v nhu l bng tay ri cho vo ni hoc m un n si, cht ra bt, chn ung ngay hoc cho vo m tch nng ung dn trong ngy, mu nc xanh ti mu lc dip. 3.1.4.2 Tr N

Tr N (n hoa ch): n cn non (n ht tiu), hi v phi trong bng rm, cho n kh mu xanh, nu phi nng th chng kh, nhng n mu , cht lng km. Cafein thp: 2%, t kch thch, c ph n v ngi gi a dng. 3.1.4.3 Tr Bng

Gm l ch gi l ch yu, gi nt, hay em bm nh thnh mu di nh nhau, 2mm-1cm, mu xanh en v hi . L ch khng ch bin, ch sy n gin bng phi hong, khng c lng tuyt. 3.1.4.4 Tr Mn H Giang

Tr Mn H Giang (ch bnh, ch chi ): nguyn liu non, mt tm 2,3 l non, ging ch Tuyt (Shan), cung di, ch bin n gin, th cng. Bp ch hi v, sao nhanh trong cho gang, ri v bng tay xong, ri ra phi nng n kh.3.1.4.5 Tr long

L ch ln men mt phn, nc ch mu vng kim ng nh, v m, hng thm c bit. 3.1.4.6 Tr en

Chim phn trm ln nht trn th trng bun bn ch th gii, khong 70%. 3.1.4.7 Tr xanh

Ch xanh (xa gi l ch lc): nc xanh vng, ti sng, v cht mnh, c hu v, hng thm nng mi cm. 3.1.4.8 Tr hng

Dng cc hng liu kh, nh hoa ngu kh, hoa cc kh, ht mi, tiu hi, i hi, cam tho, qu pha trn vi cc t l khc nhau. 3.1.4.9 Tr hoa ti

Hoa ti gm c: sen, nhi, ngc lan,si, ngu, bi qu, ngc lan xut hin cc mt hng ch mi, nh ch ti (tea bag), ch en CTC, ch c sn, ch hoa (nhi, si, ngu, sen). 3.1.4.10 Tr en mnh

Bp ch ti sau khi ho c a vo thit b v v nghin sau a ra my ct ln men sy, gi l ch en CTC, sn xut nhiu Xrilanca, n , Chu Phi. 3.1.4.11 Tr ho tan

Ch ho tan c dng bt ti xp, rt mn, gm nhng ht nh, mu vng nht (ch xanh), nu nht (ch en). Hm lng tanin, catesin, axit amin, cafeine rt cao, gp ch nguyn liu. mu nc, v ch t yu cu, nhng hng nht, v bay ht trong qu trnh chit xut, c c v sy. 3.1.4.12 Tr ti

T l ch mnh, vn c nhiu trong cng ngh ch CTC v OTD, tit kim v thu hi ch tt, c cng ngh lm ti giy c bit ng cc loi ch . Ti ch c si dy buc nhn hiu ca hng sn xut, khi pha ch cn nhng ti vo cc, ti b ch vt ln d dng. 3.1.4.13 Tr dc tho

Gm ch en trn vi mt dc liu nh c ngt, va c v ch li c gi tr cha bnh. 3.2 Thu hoch v bo qun ch

Phm cht ca ch ph thuc vo thnh phn ha hc trong bp ch nh: cht ha tan, catechine, caffeine, ngNhng vt cht c li cho phm cht ch thng tp trung ch yu vo b phn non ca bp ch. V vy, hi bp cng non, phm cht cng tt. non gi ca bp ch cn ph thuc vo thi gian sinh trng, v vy cn hi ng thi gian quy nh.

Mc khc, do c im ca qu trnh ch bin v phm cht ca tng loi ch, tiu chun hi cng khc nhau. V d: i vi nguyn liu ch bin ch en cn hi non hn so vi nguyn liu dng ch bin ch xanh.

Quy cch hi ch:

Hi bp (tm) v 2,3 l non, khi trn tn cy c 30% s bp tiu chun th hi, khng b st, khng qu la, tn thu bp m xe, 7 10 ngy hi mt la.

V xun (thng 3 4): hi cha 2 l v l c, to tn bng.

V h thu (thng 5 10): hi cha 1 l v l c to tn bng. Nhng bp vt cao hn mt tn th hi st l c.

V cui (thng 11 12): thng 11 hi cha l c, thng 12 hi c l c.

Ch n au: t u hi 1 tm 2,3 l, cha 3,4 l v l c. Cc t sau hi cha l c.

Ch n tr li, hi nh i vi ch kin thit c bn. Bo qun nguyn liu:Khi a nguyn liu t c s sn xut v nh my ch bin, th l b chuyn mu nu tng phn hoc ton phn dn n bp ch b thi nhn hon ton. V th ta khng nn thu hoch bp trong iu kin nng m nhiu. Trong qu trnh thu hi khng c lm l ch b gip nt, vn chuyn nhanh chng v ni sn xut.3.3 Cng ngh ch bin mt s loi tr

3.3.1 Tr xanh

Mi loi tr xanh c yu cu mc hi bp khc nhau. Loi tr xanh thng thng th hi 1 tm 2,3 l, cn nhng loi tr ngon v ni ting cht lng cao th hi 1 tm 1 l hoc thm ch ch hi bp non. Cht lng ca l ch ti ng mt vai tr quan trng trong c tnh ca tr xanh. Khi thu hi ch, c th thu hoch bng tay hoc bng c gii, sau c chuyn ti nh my ch bin ch. Ngi ta phi tin hnh dit men ngay lp tc, ngn chn qu trnh ln men xy ra (oxy ha catechin trong l ch) v gi li mu xanh c trng cho tr thnh phm. Ta c th v hot enzyme bng hi nc, cho sao, gia nhit.[4]

a. Dit menDit men v hot enzmyme c trong nguyn liu c bit l nhm enzyme polyphenol oxydase, khi cc qu trnh nh h hp, thy phn hay oxy ha u b nh ch. Cc polyphenol trong nguyn liu s khng b oxy ha v gi li trong sn phm vi hm lng cao nht. L ch tr nn dai hn v bn c hc cao hn. Mt phn m bay hi, mt s hp cht d bay hi cng b bay i, v th kh mi hng ca l cy ti, m sau khi dit men 59 63%.C th dit men bng hi nc hay bng khng kh nng m. Theo phng php Trung Quc th s dng cho sao, cn phng php Nht Bn th hp bng khng kh nng hay hp bng hi nc.

b. V

V l ph v cu trc ca t bo, chit dch p ra b mt l. Bt u qu trnh ln men v to hnh cho cnh tr do lm gip mt phn t bo l ch, cc cht d tan vo nc si khi pha tr, nhng tr xanh phi pha c nhiu ln, nn dp t bo khng c qu cao.

V ch xanh cn c mt thun li na l ch a vo v do c dit men di tc dng ca nhit cao nn cc cht c tnh keo dnh c trong ch c hot ha, gip cho l ch d xon chc v t b gy, nn thi gian v s ln v t hn so vi v ch en.

Cnh tr xanh phi xon chc, t gy v khng b vn cc, t l dp t bo 45 55%.

Phng php thc hin:+ Kiu Trung Quc:V kt hp vi sng nh ti v phn loi. Khi sng phn loi, phn trn c em v li, phn di sng em lm kh.

+ Kiu Nht Bn:

V sy ln 1: 40 50 pht. Khng kh nng 95 1000C c a vo thit b sy, trong thit b sy din ra qu trnh v ch. Ch c lm xon v lm kh ti m 60%. Sau khi v sy ln 1. ch c tri ra (15 20cm), lm ngui v ch n nh (20 30 pht). C s to hng trong qu trnh ny.

V ch (24 pht).

V sy ln 2 (40 pht). Ch c cun trong nhng bn nn v ng xoay trn b tr trong bung sy. m 30%, bt u cun trn li.

V sy ln cui (40 pht). Tip tc v v sy 100 1050C. m 13%, c hnh kim, to hng.

c. Sao kh

Sy trc sao sau: y l phng n tt nht cho sn xut quy m va v ln, bo m c nng sut v cht lng tr xanh thnh phm. Phng n ny chia giai on sao kh (ch bin nhit) tr xanh lm hai bc:

Bc 1: lm mt i mt lng nc ng k trong ch, m bo mu sc ca nc ch nn s dng nhit cao nhng khng lm chy ch v gim m ca ch n gii hn nht nh.

Bc 2: ko di thi gian ch bin nhit kt hp vi lm kh ch, chuyn ha v ch v to hng thm c trng cho ch xanh sn phm.

C th tm tt bin php v ch cng ngh ti u cho giai on sao kh ch xanh nh sau:

Bc 1Bc 2

Nhit sy: 90 95oC

Thi gian sy: 15 pht

m ca ch: 18 20%Nhit sao: 60 70oC

Thi gian sao 60 pht (c th ko di 2 3 gi nhit : 50 60oC

m ca ch: 4 5%

m ca ch s ch: 8 10%

Nhit khi ch cn nng: 60 700C

Thi gian nng: 4 5 gi

xong nhit khi ch vn nng: 40 500C

Sau khi ngui m cn li ca tr nm trong gii hn tiu chun: 5 6%.

+ Phng php lm kh ch v bng cch sao:

Cho sao hoc thng quay

Nng sut thp, mi d chu, cht lng cm quan khng cao

+ Phng php lm kh ch v bng cch sy sao:

Sy: 120 1400C, 6 12 pht, m 30 35%.

Sao ln 1: 110 1150C, 20 25 pht, m 20%, si ch cht, c hnh xon cht, thng v c mu xanh xm.

Sao kh ln 2: 90 1000C, 20 30 pht. Thit b: cho gang khp li, lu c cu o trn (20 30 rpm). m khong 5%.

3.3.2 Tr en

Khng ging nh tr xanh phi v hot enzyme, tr en cn s hot ng ca h enzyme hnh thnh cc sc t (theaflavin v thearubigin). Trong cc qu trnh sn xut tr en, th qu trnh ln men l quan trng nht, nh hng ln ti cht lng ca sn phm.[4]

d. Lm ho ch (withering)

iu chnh nng cht kh ca l ch: tng nng c cht ca phn ng oxy ha tin dn n nng ti thch ca h enzyme c trong l ch. Lm cho ch ti mt i lc trng v to cho n tnh n hi, tnh mm do rt cn cho vic thc hin qu trnh v sau ny. C th t mc ch ny vi iu kin: lng m c trong ch ti gy ra lc trng t bo c bay hi. [2] m cui ca nguyn liu:

-Lm ho t Soft wither: 60 65%

-Lm ho bnh thng Medium wither: 60 65%

-Lm ho nhiu Hard wither cn li 58 60%

-Lm ho rt nhiu Very hard wither Sn phm c mi hng rt c bit. Lng m mt rt nhiu, n mc l ch tr nn qu kh cho phn ng oxy ha v gi li mu xanh cho tr.

Trong tng thng th m ca ch ti dao ng khc nhau, v th cn lu ti m lm ho trong tng thi im trong nm hay tng ma trong nm.

Mc ho ca mi bp ch ng u nhau

Cm quan ca nguyn liu:

Trong sn xut, vic kt thc s lm ho c xc nh theo hm lng nc trong l ch ho (hm lng nc phi chim 60 62%). i khi ngi ta dng phng php cm quan n gin: cung ca bp ch ho khng th b gy c v nm cht cc l ch trong bn tay th n kt li thnh nm.[2]Bin i ha hc:

m gim: t 76 80 % gim cn 62 63 % i vi l ch non, cn 64 67% i vi l ch gi.

Cht tan tng ln do s thy phn ca cc cht cao phn t.

Cc cht mu, cht hng c hnh thnh (do catechin b oxy ha ri kt hp vi polyphenol hoc alanine, hoc asparagine).

Protein bin i su sc to thnh cc axt amin ha tan.

Tn tht cc cht d bay hi.

Tng lng tannin gim khng ng k (1 2% theo cht kh). Khi t ti cng 1 ch lm ho nh nhau, nu dng nhit cao lm ho l ch s gy ra s tn tht ln v hm lng tannin. Trong cng mt ch nhit , nu m ca ch ho cn li t th tn tht tannin cng ln.Mt s cht gim i nh: vitamin C, dip lc, tinh bt.

Cafein c tng ln mt t do lng axt amin tng ln to iu kin cho thnh hnh cafein.Mt s thng s lm ho:Nhit phng: Nhit khng c vt qu 46 480C trnh nh hng xu n hot tnh ca cc enzyme trong l ch, v m bo lm ho ng u ca khi ch.T nhin: 20-240C,

Nhn to lp ch mng: 32-330C,

Phng php lm ho ch: t nhin, nhn to, lm ho lnh

Lm ho t nhin:

Tin hnh trong cc phng chuyn dng b tr cc tng trn ca nh my. Khi p dng lm ho t nhin th a im ca nh my c nh hng n cht lng lm ho. Nh my xy dng t trng, vng ng ly s b chn gi nn khng kh b t hm, qu trnh lm ho thng hay b ko di l ch b hp hi nhanh hn so vi c lm ho. Nn ta phi xy dng nh my ni cao thong, to iu kin lm ho nhanh hn v kh nng thu c ch tt. [2]Lm ho nhn to:

Mng lm ho l mt ci ng hnh ch nht vi mt mt h cho khng kh vo v cho hi nc bay ra t l ch cha trong mng. Kh c thi vo mng bng mt ci qut t u vo, nh b phn khuch tn gip cho dng kh n nh lu lng. Khi qua mng, kh s mang theo m t l ch. Kh dng y l khng kh lnh vo ban ngy khi m tng i thp v khng kh nng vo ban m khi m tng i ca cao. [2]Qut thi khng kh theo mt chiu v pha trc v kh c th i t trn xung di hay t di ln trn nh vo h thng ca chp t u vo v u ra ca mng m khng cn qut phi i chiu quay. thit b ny, vic dng tay xo trn ch l hu nh khng c nn l ch cng t b tn thng hn. L ch nm trong thit b ny cng c cch ly vi mi trng ngoi tt hn nn khng b nh hng bi s thay i t ngt ca mi trng khng kh xung quanh. Tuy nhin, thit b ny, vic nhp liu v tho sn phm th kh hn so vi mng h, v cng kh quan st tin trnh lm ho hn. [2]C 2 hng i ca dng kh:

Hnh 3.2 S hot ng mng kn khi dng kh i t di ln

Hnh 3.3 S hot ng ca dng kh khi i t trn xung

e. V ch

Mc ch ch yu ca v ch l lm gip v ph v t bo, dch p tro ln trn b mt l, nn n chu tc dng ca khng kh v enzyme. L ch ho c xon li theo hnh xon c, dch p t bo tro ra khi t bo v bao ph dn b mt ca l. Bn cnh qu trnh v cng lm gim mi hng ca tr khi pha.[2]Khi pha ch dch p c chit ra t t bo ca cc l v c lm kh trn b mt ca chng s d dng ha tan ra nc pha, trong khi dch p ca t bo c lm kh trong cc t bo khng b ph v kh tan hn, nn cc loi tr c mc v khc nhau s c ha tan khc nhau.[2]Cc bin i vt l trong qu trnh v ch [2]Trong qu trnh v cc bp ch b bin dng rt ln. L v cung c non v bn khc nhau. Trong thi gian v chng dn dn b t ra tng phn ring bit, nh trong lc phn loi ch v tch ring ra c tng phn, hoc tng nhm ring bit c non khc nhau.

tch hon ton l ch thnh tng phn, hin nay cc nh my ch ngi ta dng hai, ba v bn ln v, hn na sau mi ln v l ch c a i phn loi.

Ch thu c khi v nh cho nc pha km, trong khi ch thu c t nhng l ch c v mnh nc pha m hn.

i vi nhng l ch c lm ho n nng ca dch p khc nhau i hi phi c cc bin php v khc nhau. Nhng l ch c lm ho nh phi v nh v nu v mnh chng s b vn nt; nhng l ch c lm ho mnh, phi c v mnh chit dch p t cc t bo v to cho n kh nng b oxi ha.L ch c lm ho nh, trong qu trnh v c th thm ht dch p b chit ra t nhng phn dp, ng thi khi phc li lc trng v lm x l ch ra. trnh lm x l ch v to cho ch c hnh dng bn ngoi gn p cn phi lm ho l ch n m cn li thch hp nht.

Nhit tng ln trong qu trnh v t 4 60CNhit chV ln 1V ln 2V ln 3

TTTTTT

26,230,24,029,83,6292,8

25,431,05,630,04,628,43,0

25,230,25,028,23,027,32,1

Cc bin i ha hc trong qu trnh v ch:

-S xm nhp ca kh Oxy

Trong khi v ch, cc qu trnh sinh ha xy ra mnh v lin quan mt thit vi lng oxy xm nhp vo khi l. So snh s xm nhp ca oxy vo khi l trong tt c cc qu trnh ch bin, ta c:

+ Giai on lm ho ch: chim 14%

+ Giai on v ch: chim 72,5 %

+ Giai on ln men chim: 13,5%-S tng nhit

Trong qu trnh v, do lc ma st v nhit sinh ra ca phn ng oxy ha, nhit khi ch tng ln 4(6 oC. S tng nhit khng u lm cho qu trnh oxy ha xy ra mnh v cc b, nh hng xu n phm cht ca ch.

lm gim nhit khi l v iu chnh qu trnh oxy ha xy ra u n ng mc, ngi ta khng v ch lin tc qu lu m v nhiu ln, sau mi ln v u c sng phn loi v lm ngui.

-S oxy ha tannin lm cho hm lng ca tannin ha tan gim, hm lng ca catechin gim, hm lng cc tannin c bit tng ln.Hm lng benzadehit, ru benzilic, n-pentanol, v cis-3-hexanol tng mnh, n-heptanol gim.

Lng chlorophyll gim: cn 30% ban u sau 120 pht.

Lng vitamin C gim

Phng php thc hin v thit b:

V ch thng tin hnh lm 3 ln, mi ln v 45 pht, sau mi ln v c sng phn loi ch tch nhng phn ch nh lt sng a i ln men trc, phn ch to khng lt sng a i v tip tc.

V ch en, ln th nht tin hnh trong cc my v m, nhng ln v sau mun tng thm dp t bo ca l ch nn tin hnh trong cc my v c bn (np) p.

Tiu chun quyt nh kt thc giai on v hoc nh gi cht lng v ch, ngoi xon cht, l t l dp t bo ca l, qui nh ( 80%.

Qu trnh v ch to p lc xon nhng l ch vi nhau cng nh ch xt nhng l ch vi b mt ca thit b v. ln ca p lc ph thuc vo lng l ch a vo thit b v v tr ca np.

L ch sau khi v c ly ra khi thit b v i qua 1 ci ry. Ry c c thng vi nhng kch thc khc nhau. Nhng mnh ch i qua l ry (gi l fine leaf) th c a i ln men, cn phn khng lt qua ry (coarse leaf) th a i v li.

Thit b: Bn v (rolling table)1 bn hnh trn lm gia ng bi 1 ca pha di

Mt ci trm hnh tr gi l v c mt phu nhp liu 1 u

Mt ci a hay np to p lc

3 ci quay tay t cch nhau 120o, mt tay quay dng iu khin bn hoc ci trm hoc c 2 di chuyn theo qu o lch tm. Hnh 3.4 Bn v (rolling table)

Hnh 3.5 L ch c p xung trong khi bn v quay

Hnh 3.6 L ch c xon li t t ng thi qu trnh ln men xy ra

f. Ln men

To ra cc bin i sinh ha nh vo h enzyme oxy ha (polyphenoloxidase v peroxidase) to ra sn phm ch en c mu sc v hng v c trng.

Qu trnh ln men chia lm hai giai on. Giai on th nht gn cht vi qu trnh v, do trc khi kt thc qu trnh v ng thi c cc bin i ha sinh thuc v qu trnh ln men. Sau khi v, cc bin i ha sinh tip tc v chng thuc v giai on th hai ca s ln men, trong giai on ny khng gy ra tc dng l hc i vi l ch. Vic phn chia qu trnh ln men nh trn mang tnh cht tng i v theo quan im ha sinh v v ln men c coi nh mt qu trnh thng nht.[2]Do s ln men xy ra mt cch t pht, cho nn phi lun lun ch sao cho qu trnh ny xy ra trong nhng iu kin thun li. Khi ln men cn phi:

+ Duy tr trong phng m tng i cao v nhit thch hp nht, ri ch thnh lp thch hp nht i vi s ln men, cung cp mt lng cn thit khng kh cho phng ln men, bo m phng ln men tuyt i sch s, nh ch ngay tc khc s ln men sau khi ch c ln men, ngha l lc ch c c cc tnh cht c trng ca ch en.

+ Cc bin i b ngoi trong khi ln men, th hin s to ra c dn dn cho l ch mu nu v s pht huy hng thm t ti cc i vo cui lc ln men.

Cc bin i chnh trong qu trnh ln men:

Vt l: nhit

Qu trnh ln men l ch c bt u t ngay giai on v ch khi cc t bo ca l b ph v cho n khi xp ch vo khay v t trong phng ln men cc qu trnh oxy ha trong ch mi xy ra mnh lit. Nhit ca khi ch ln men tng ln cho n khi kt thc qu trnh ln men, sau bt u gim xung.

Nhit ca khi ch ln men l mt trong cc ch tiu khch quan xc nh im kt thc ca qu trnh ln men.Ha l: s ng t pectin do c th tip xc vi kim loi nng. S thay i hm lng ru methylic,t lc ph v cc t bo ca l ch v c s tip xc ca dch p vi khng kh xy ra s bay hi ca ru methylic nh tnh d bay hi ca n. ng thi methylic tham gia vo vic to thnh ester gip to hng ca ch trong khi v v ln men ch.

Ha sinh:-S bin i ca tannin trong qu trnh ln men ch

Trong thi gian ln men ch lng tannin gim i rt ln, thng chim khong 50% hm lng ban u ca n trong nguyn liu. Bn cnh s tn tht v hm lng, trong qu trnh ln men tannin cn bin i su sc v thnh phn cc cu t. Hin tng ny thy rt r 2 gi u tin, sau cng tn tht ca chng gim dn.

Trong qu trnh ln men nhm cht Catechin trong hn hp tannin ch gim xung do.

+ 1 phn tannin chuyn ha thnh tannin c bit, chnh l cc sn phm oxy ha ca chng khi ln men.

+ 1 phn sau khi ngng t thnh hp cht ln hn kt hp vi protein to thnh nhng cht khng tan.

Nh s oxy ha nhm cht Catechin v lm tng hm lng nhm cht tannin c bit nn v cht ng ca ch mt i v thay vo l v cht du d chu ca ch en.-S bin i ca cc saccharide

Trong thi gian ln men, lng monosacaride, disacaride gim xung do tham gia vo qu trnh to thnh cc phc cht to cc cu t hng v mu.

Theo Khorobava:

+ Lng monosaccharide gim t 1,97% xung 1,64%.

+ Lng disaccharide gim t 1,25% xung 0,5% (theo cht kh)

-S bin i ca protein

Trong qu trnh ln men, di tc dng ca enzyme Protease cc protein b thy phn thnh cc acid amin, chng cng cc acid amin t do khc gp phn iu v cho nc ch ng thi to hu v tt sau khi ung.

mt s ni trn th gii, ngi ta thng ung ch en vi sa, ng v ca ch t cht, t ng hn v TFs, TRs, v Catechin trongch en kt hp vi Casein ca sa to phc, lm cho v ch du i. Ngy nay vi s pht trin ca khoa hc k thut, ta c th sn xut ra cc lai ch en tch Caffeine, nhm p ng cho nhng ngi khng thch v ng ca ch.

Ha hc: Cht ha tan gim (protein + polyphenol)

Lng monosaccharit v disaccharit gim: to hng v mu

Hp cht nito khng bin i nhiu

Nu tin hnh ln men ch trong iu kin m v thi gian va , s to thnh flavonoids s lm tng mc sng ca nc ch. Tuy nhin, nu ln men cng vi iu kin m, nhng thi gian li qu di, mu ca nc ch s m hn do hm lng thearubigins to ra nhiu hn v lng theaflavins to thnh s t hn. V vy, vic nh gi lng theaflavins to thnh l c xem l cch xc nh thi gian ln men ti u.Cc bin i v cht mu:

Mu sc ca ch en khi pha khng phi l mu en, m c mu cam sng, hi hay nu. Cc cht mu c trng cho ch en c hnh thnh ch yu trong qu trnh ln men. Cht mu ca ch en l tng hp ca nhiu hp cht to mu khc nhau gm cc loi chnh sau:

Theaflavins (TFs)

Thnh phn TFs trong ch en chim khong 0,2 0,3 %. Cc Theaflavin ny c to thnh bi s oxi ha cc hp cht quinon. Di tc dng ca enzyme polyphenoloxidase chuyn ha t Epicatechin v Epigallocatechin thnh cc hp cht trung gian l cc hp cht quinon, c th nhm Galloyl ester ca catechin b oxi ha to thnh benzotropolone. Cui cng cc hp cht quinon ny kt hp li vi nhau to nn cc loi Theaflavin khc nhau. Chnh cht ny to mu cam cho nc ch khi pha. Trong cc loi Theaflavin, Theaflavin monogallate to mu sc sng hn Theaflavin, Theaflavin digallate cho mu sng hn nhiu so vi Theaflavin monogallate.

EGC + EC TheaflavinEGCG + EC Theaflavin-3 monogallate

EGCG + ECG Theaflavin33 digallate

EGC + ECG Theaflavin3-monogallate

GC + EC IsotheaflavinGC + C Neotheaflavin

Hnh 3.7 Cc phn ng to cc theaflavins trong ln men ch en

Thearubigins(TRs)

Trong ch en Thearubigin chim khong 10 20 %, l hn hp cc cht mu phenol, c khi lng phn t t 700 n 40000 Da. Chng c to thnh do phn ng trng ngng. TRs c to thnh do s oxi ha bt k Catechin no hoc do s kt hp gia chng di s xc tc ca enzyme Peroxidase. Trong qu trnh ln men, mt lng ln TRs tng ln tng ng vi lng TFs gim i. iu chng t c s chuyn ha TFs thnh TRs trong qu trnh ln men. Thearubigin to mu nu cho ch en.

Cng mt lai ch en c ngun gc t cc vng khc nhau s c mu sc khc nhau. Chnh mi quan h gia Theaflavin v Thearubigin quyt nh cho mu sc ca nc ch khi pha. Nu hm lng TFs cao th nc ch c mu sng hn, ngc li nu hm lng TRs qu cao s lm cho nc ch c mu nu ti.

Trong qu trnh to mu TRs, c th xy ra cc phn ng trng ngng khng thch hp cc Catechin v cc hp cht phenol khc to nn cc sn phm km tan trong nc ch. y chnh l nguyn nhn lm cho nc ch b c.

Anthocyanidin

Trong qu trnh ln men, anthocyanidin b oxi ha to nn cc cht tan trong nc to cho nc ch c mu ng . Khi hm lng anthocyanidin trong ch nguyn liu cng nhiu th mu nc ch en thnh phm cng p.

Bn cnh TFs, TRs, Anthocyanidin to mu chnh cho sn phm ch en, cc phn ng to phc ca cc mono- v disaccharide, cc acid amin cng gp phn to nn mu sc cho ch. Trong qu trnh ln men, hm lng monosaccharide gim t 1,97% xung 1,64 %, disaccharide gim t 1,25% xung 0,5%.

Cc bin i v mi:

Ch en c mi thm nh, d chu, ging nh mi to chn, mi hoa hng. Mi ca nc ch khi pha l tng hp ca nhiu hp cht to mi khc nhau. C th chia cc hp cht to mi thnh 2 nhm:

Cc cht to mi c sn trong nguyn liu

Trong l ch ti c nhiu hp cht to mi khc nhau. Trong , mt s hp cht d b bay hi trong qu trnh lm ho, c bit trong qu trnh sy kh, nh , hexenol, n-hexanol, , hexenal. Trong ch en cn mt s tinh du bn nhit nh benzylic, benzyl methylic, benzaldehyde, geraniol, linool v cc ester ca chng vi acid caproic, cng mt s aldehyde khc.

Cc cht to mi hnh thnh trong qu trnh ch bin

Ngi ta xc nh c hn 600 hp cht c nh hng n mi ca ch thnh phm, trong cc ru monoterpene (nh linalool, gernariol), cc ru thm (ru benzylic, 2 phenylethanol) l nhng thnh phn chnh to nn mi thm cho ch. Ngi ta cho rng nhng cht mi c chc ru ny c mt trong l ch di dng cc glycoside, trong qu trnh ln men s c gii phng bi enzyme ni bo glycosidase. Cc glycoside tin thn cho nhng cht to mi trong ch ny c phn lp, ch yu l cc diglycoside, gm cc thnh phn nh sau: primeveroside (6oD xylopyranosylD glucopyranoside), acuminoside (6oD apifuranosylD glucopyranoside), v D glucopyranoside.. Trong , primeveroside l glycoside c tm thy nhiu nht. Bn cnh , ngi ta cng phn lp c 1 enzyme c khi lng phn t l 61 kDa, lm nhim v thy phn cc glycoside tin thn ny trong ch ti to cc hp cht mi cho ch en, v t tn l ( glycosidase.

Bng cc th nghim, v phn tch thnh phn ca cc cht mi trong ch, ngi ta kt lun ( glycosidase l mt enzyme ch lc trong qu trnh to ra mi thm c trng cho ch en trong qu trnh ln men. iu ny cng c cng c hn na v ( glycosidase cn c tm thy khng ch trn cy ch m cn c tm thy trong cc loi hoa v tri cy to mi c trng cng bng c ch nh vy.

Hng thm ca ch thnh phm cng c gp phn bi s tng tc gia ng v acid amin, gia acid amin v tanin. Hin vn cn rt nhiu gi thit v c ch to hng thm trong qu trnh ln men ch en, song cc hp cht to hng thm c th thng nht theo bng sau

Catechin c nh hng n s to thnh mi thm cho ch. Cc th di y cho thy khi hm lng catechin gim s lm cho tng hm lng cc cht thm tng, c bit l cc ru monoterpene, y l cht rt quan trng i vi hng ch en thnh phm. Bn cnh , Takeo v ng nghip (1985) chng minh rng, nu nh loi b c hon ton catechin th s to thnh cc hp cht thm nh geraniol v linalool s tng ln ng k.

Hnh 3.8 S thay i ca tng hm lng cc cht mi v hm lng catechin trong cc giai on sn xut

Cc bin i v v:

V ca ch c to nn do s cn bng gia cc v c bn nh: ng, cht, ngt, umami. Mc d v ng, cht gy cm gic kh chu nhng i vi sn phm ch hai v ny l tnh cht quan trng to nn cht lng cho nc ch pha.

V ng, cht trong ch l do Catechin. ECG, EGCG to v ng v cht, trong khi EGC, EC, to nn v ng v hu v ngt. Cng v ng, cht c th xp theo th t sau ECG>EGCG>GCG>EC>EGC = GC>C. T cho thy Gallated catechin c v ng v cht hn cc non-gallated Catechin. Bn cnh cc Catechin c sn trong nguyn liu, cc Theaflavin c to thnh trong qu trnh ln men cng gp phn to v cho ch. Trong , Theaflavin digallate c v ng v cht hn hn so vi Theaflavin monogallate.

Caffeine trong ch chim khong 2,5 4 %, to v ng gt cho ch. Trong qu trnh ln men c s to phc gia caffeine v hp cht phenol lm gim hm lng Caffeine gip iu v cho nc ch pha. Sn phm ca qu trnh ny l Caffeine Tannate, tan trong nc nng khng tan trong nc lnh.

Cc Flavonoid c trong ch thng c v ng nhiu hn cht v khi cc Flavonoid c kch thc hay khi lng phn t cng tng th c v cht nhiu hn ng. Trong qu trnh ln men, cc Polymer Flavonoid b thy phn to cc mch nh hn lm cho ch en c v ng nhiu hn. V ng ny du, d chu hn v ng ca Caffeine.

Thng s cng ngh

Nhit t: 20 250 C

Thi gian: khong 2 3 gi.

m tng i ca khng kh t 95 98 %, i vi ln men trn sn tin hnh thng gi nhn to vi lng khng kh cn trao i bng 4 5 ln th tch ca phn xng trong mt gi, tc lun chuyn khng kh: c 15 pht ton b khng kh trong phng c i mi.

Chiu dy lp ch trn khay ln men: ln men trn sn 4 6 cm, s dng mng su c thi kh l 13 20 cm.Phng php

Oxi ha trong cc mng su v c thi khng kh c iu chnh: thng s dng thit b ln men lin tc dng bng ti.

Thit b s dng

Thit b ln men lin tc: (CFM)

Hnh 3.9Cu to thit b ln men lin tc dng bng ti li

Hnh 3.10 Thit b ln men lin tc

Thit b ln men lin tc (CMF) c cu to l mt bng ti chuyn ng lin tc v tc ciu chnh ph hp. Khi ch sau khi v c tri u trn li bng ti (c l) v b dy nht nh.

Khng kh c dn qua ng ng vo thit b ln men bng qut c iu chnh tc , m v nhit . Lu lng khng kh c th iu chnh c nh tm chn ngay ca vo ca dng kh.

g. Lm kh sy tr

Sy l qu trnh cng ngh cui cng ca ch bin l ch. Mc ch ca sy l c nh trong l ch cc tnh cht c to thnh n trong qu trnh ln men bng cch nh ch hot ng ca cc enzyme di tc dng ca nhit cao. Lng m d tha cng c kh b trong thi gian sy, c th 3 5%.

V s dng nhit cao trong thi gian sy, cho nn ngoi vic tiu dit cc enzmyme trong l ch cn xy ra hng lot cc bin i khc, trong quan trng nht l s bay hi ca tinh du. S tn tht tinh du c th khc nhau ph thuc vo iu kin sy m trc ht l ch nhit v ch khng kh. Cht lng ca thnh phm ph thuc mc cao vo ch sy.

Bin i ha hc:

Cc cht thm ca ch b gim i.

Trong qu trnh sy, bin i r nt nht l s tn tht cht hng m ch c c trong khi ln men: s bay hi ca cc aldehyde d bay hi, cc acid hu c; s oxy ha hydrocarbon v ru khng no.

Hm lng glucose, saccharose, tinh bt gim i trong qu trnh sy. Trong qu trnh sy, nh phn ng caramel ha ca cc cht ng m ch s c nhng mi thm c o.

Ngoi ra phn ng Maillard gia ng v acid amin cng gp phn hnh thnh nn hng thm v mu sc c trng cho ch.

Vitamin C b gim rt ln trong qu trnh syChlorophyll b chuyn ha thnh pheophytin v pheophorbide nhit cao trong qu trnh sy cng gp phn hnh thnh mu nu en cho ch bn thnh phm..Phng php thc hin:Cc giai on din ra trong qu trnh sy ch

-Giai on ng tc:Trong sut giai on u ca qu trnh sy, l ch cn rt m v lp m tn ti khp b mt. Nhit ca l ch lc ny gn bng vi nhit bu t ca kh sy. Lp m b mt c loi b rt d dng v t l bc hi c lp vi hm lng m ca vt liu, iu c ngha m bay hi vi mt tc khng i. -Giai on gim tc:

Giai on ny m t bn trong vt liu s di chuyn ra b mt, s bay hi m b mt vt liu gim dn, nhit vt liu tng dn. Lng m bay hi trong giai on ny th t trong khi thi gian li kh di. V vy, giai on ny c nh hng quan trng n thi gian sy v ph thuc vo kch thc nhng mnh ch, b dy lp vt liu v cc iu kin khc nh: tc thi kh, nhit v m ca khng khCch tin hnh:

Hu ht cc nh my sn xut ch u tin hnh sy bng my, cn ch chnh cc thng s ca qu trnh sy cho hp l.

Ngi ta c th sy mt ln hay hai ln

Sy mt ln: Nhit t 90( 5oC trong 23-25 pht, m sau khi sy t 3-5%

Sy hai ln:

Ln 1: nhit t 90 ( 5oC trong 15 pht, m sau khi sy ln 1 l 18-20%

Ln 2: nhit 80 ( 5oC trong 15 pht, m sau khi sy ln 2 l 3-5%

Gia hai ln sy, ch c ri mng, lm ngui ch phn phi li m cho ng u, trnh hin tng kh cc b v trong t ngoi kh.

Ngoi nhit sy trn ngi ta cn c th p dng sy 128oC, phng php ny sy nhanh, nng sut cao nhng rt kh khng ch cc chtiu k thut.

Tc khng kh sy: khong 0,5m/sThit b: My sy bng tiMy sy l t kim loi kn 8, bn trong c t 4 n 5 nhnh bng ti (3) Cc bng chuyn c sn xut bng li thp khng g vi kch thc l 20 1.5 mm, v mi bng c cng ra trn cc tang truyn ch ng (7) v tang b ng (5). Cc bng ti c b rng khc nhau ph thuc vo nng sut ca my sy. Mi bng c th c b dn ng c lp vi hp gim tc, hoc c th c b dn ng chung cho php thay i tc ca cc bng ti t 1,14 n 1,0 m/pht. Khng kh sy cho vo di nhnh th hai ca bng ti v c un nng nh cc calorife hi (4) lp gia cc bng li ca mi nhnh. Khng kh xuyn qua tt c cc bng li v sn phm nm trn . Khng kh c bo ho m c qut (2) thi ra ngoi.

Sn phm trc khi sy cn tn nh s b v bng ti 1 chuyn n nhnh trn ca bng chuyn my sy. Sn phm cng vi bng chuyn n u cui cng ri xung bng di.

Ngoi ra tng hiu qu cho qu trnh sy, trong my sy ngi ta trang b thm b phn ri t ng gip phn b u vt liu, bn trong c nhng my co trnh s tch t l ch trn li.

Pha trn c h thng cm bin heo di nhit kh thi, qua c th iu khin ng m van tho liu

Hnh 3.11 S nguyn l ca my sy bng ti

h. Phn loi

Ch sau khi sy qua sng trn v sng bng phn loi cc loi ch kch thc khc nhau.

Hnh 3.12 My sng phn loi

C th chia cc loi ch thnh phm nh sau:

Ch cnh hay ch si: OP, P,S (thng bn trn th trng)Ch mnh hay ch gy: BOP, BP, BPS (tr ti lc)Ch vn: F, D (tr ha tan)

+ OP: tm v l 1 ca bp (t), ln mt t cung non, c cht lng cao, cnh xon p, en bng. Nc ti, trong sng, v cht du, hng thm cao.

+ P: tng i non, ch yu l 2 v phn non l 3, cnh tr u, si to, cht. Nc c mu sc, hng v tng i tt.

+ S: on gia l 3, si th t xon, v cht, mu nc tng i m, sng ti km, cht lng bnh thng.

+ BOP: tr mnh, non rt cao, ch yu l phn gy ca tm, phn gy ln 1, c nhiu tuyt vng, nh u. Nc pha ti, m, trong sut, v cht, hng thm cao, cht lng cao nht, th trng rt chung.

+ BP: mnh gy ca l 2, mt phn mnh gy ca l 1. Hnh dng gn ging BOP, nhng khng c tuyt vng. Nc km ti, tng i tt.

+ BPS: mnh gy l 3, l n v mt phn mnh vn l 2. Ngoi hnh to hn BOP v BP, nc m nhng cht ng.

+ F: tr vn b nt ra trong qu trnh phn loi, nc ti, v ng.

+ D: tr bt, nc c, cht ng.CHNG 4: CNG NGH CH BIN TR HA TAN4.1 Ngun gc

4.1.1 Ngun gc chung

Cuc sng ngy cng pht trin, con ngi ngy cng bn rn hn, do mt loi tr c th pha v ung lin ra i. Trong thi gian gn y, mt loi tr ang tr nn ph bin l tr ha tan. S tin dng ca n l do c th pha ch v ung ngay, khng mt nhiu thi gian tr ngm nc nh tr truyn thng. Loi tr ha tan ny c pht trin trong nhng nm 1930, nhng khng c s dng rng ri nh hin nay. N xut hin ln u tin Anh, t tr en nm 1940, Nestea l loi tr ha tan u tin c gii thiu vo nm 1946, trong khi Redi-Tea xut hin ln u nm 1953. Nhng sn phm ny thng i km vi hng v thm vo, chng hn nh vani, mt ong hoc tri cy, v cng c th cha sa bt.

4.1.2 Ti Vit NamSau 1975, din tch v sn lng ch en, ch xanh trong mi nm u, tip tc tng khng ngng (50800 ha, 28200 tn kh-1985). Cc loi ch truyn thng dn tc (ch ti, n, l ga) ch bp, ch hng gi giy li tng nhanh.

Thi k i mi v m ca (1986-1996), th trng tiu th ch trong nc tr nn si ng, nhanh chng v chng loi, mu m, bao b, phn phi xut hin cc mt hng tr mi, nh tr ti (tea bag), tr ha tan, tr en CTC, tr c sn, tr hoa (nhi, si, ngu, sen).Vi s tin dng ca tr ha tan, hin nay chng ngy cng c a chung v p ng nhu cu ca ngi s dng. Mi gi tr c khi lng t 10 20 g. Thm vo 100 200 ml nc si l c mt ly tr: tr chanh, tr gng, tr xanh, tr chanh dy v.vTy theo s thch, khch hng c th chn lai tr c ng hoc khng ng, tr nguyn cht hay p hng liu, tr chanh hay tr thng v.v.V loi tr ha tan c a chung, s dng rng ri hin nay l thng hiu tr Lipton. Ngi u tin sng lp ra thng hiu s 1 th gii l Thomas Lipton, mt ngi chu u. Nhng cng ngh mi gp phn lm a dng ho cc sn phm tr Lipton vi cc loi tr ti, tr ho tan v c tr trong lon ung ngay. V m ca tr truyn thng c kt hp vi rt nhiu hng v khc nhau tu theo s thch v khu v ca ngi tiu dng nh tr chanh, tr o, tr du, tr bc h.4.2 Cng ngh sn xut tr ha tan

4.2.1 Tr ha tan dng bt

4.2.1.1 Gii thiu [8]Sn xut tr ha tan thng qua vic dng nc nng trch ly cc cht tan trong ch, sau em i sy phun to ra sn phm bt tr ha tan. Cc sn phm gi c hng v, mu sc v c trng ca tr. Cc sn phm t ba dng nguyn liu nh tr xanh, tr oolong, tr enhoc theo nhu cu ca khch hng. C th ung tr ha tan vi nc lnh hoc c th pha vi nc nng, ty theo s thch ca tng ngi. Phn loi ch ha tan hin nay:

Tr ha tan ung nng (tr ha tan tinh cht): tr ha tan en, xanh, oolong Tr ha tan ung lnh (tr ha tan c ph gia): thng l tr en ha tan c trn vi ng, acid citric, cc ph gia to hng (hng chanh,o, cam), to mu.

Hin nay, tr ha tan c ph gia c phn chim u th hn so vi tr ha tan tinh cht, tr ha tan tinh cht thng lm bn thnh phm sn xut tr ha tan c ph giaBt tr ha tan xanh

ItemSpecificationRemark

AppearanceYellow Powder

Soup ColorYellow and Green

Total tea polyphenols>35%VIS

Caffeinee