Phn 2: K THUT SN XUT BT CHANH2.1. Gii thiu sn phm bt chanh: Bt chanh l 1 sn phm c sn xut t qu chanh ti dng bt mn, mu trng tan hon ton trong nc c s dng lm thc ung gii kht, b sung vo cc sn phm bnh ko to mi v c trng,sn phm bt chanh d s dng, tin li, c quanh nm, thi gian bo qun di hn so vi tri cy ti. Mt khc bt chanh cn gip lm chm s lo ha, kch thch tiu ha, tng cng h min dch,2.2. Nguyn liu:2.2.1. Chanh: 2.2.2.1. M t:

Cy chanh c tn khoa hc l Citrus Limonia Osbeck, thuc h cam qut Rutaceae. Chanh l mt loi cy nh, cao t 1m n 3m. Thn c gai. L hnh trng, di t 5,5 n 11cm, rng 3,5cm n 6cm, mp l c hnh rng ca. Hoa trng, mc n c hay tng chm 2 n 3 hoa. V qu c mu xanh, mu xanh chuyn vng khi qu chn. Qu chia lm nhiu mi. Dch qu rt chua. V qu l chanh c nhiu tinh du. Cy chanh c trng khp ni nc ta. Nhn dn thng trng chanh ly qu n hoc lm gia v. Y hc dn gian s dng v qu, l v r cy lm thuc.2.2.2.2. Thnh phn ha hc:Theo nghin cu ca nhiu nh khoa hc, thnh phn ca tng loi chanh c khc nhau, nhng ni chung trong mt qu chanh thng v chim t 13 - 24%, dch chanh t 23 - 75%, cht x t 13 - 38%, ht t 5 - 7%. Thnh phn chnh gm 1% protein, 11.1% carbonhydrat, 0.9% du bo, 0.3% cht v c, 0.07% Ca, 0.001% P, 2.3% Fe v nhiu loi nguyn t vi lng khc... Ngoi ra, chanh cn c Vitamin C v nhiu cht c li cho sc khe con ngi. Dch p ca chanh qu (b v) cha 6.56 - 7.84% axit hu c ton phn (ch yu l axit citric), 0.26 - 4.13% ng ton phn... Vi thnh phn t nhin phong ph dinh dng v cc nguyn t vi lng nn dch chanh c s dng rt rng trong ngnh cng nghip thc phm. Tinh du v chanh c mi thm nh rt c trng nn cng l mt cht thm ph bin dng trong th gii m phm. Trong thc phm, chanh cng c s dng nhiu.2.2.2.3. Dc tnh v cng dng:- Chanh c chc nng gii c, bo v thnh mch, tng cng h min dch v hn ch tc hi ca nhng gc t do lm chm s lo ha. Kt qu nghin cu ca nhng nh khoa hc Nht Bn cho bit chanh c th lm gia tng 19% lng mu lu thng trong h thng cc tnh mch, mao mch v lm gim nguy c mu ng.- L chanh hoc phn v ngoi ca qu chanh khng nhng c th kch thch tiu ho, trung ho bt v bo ca thc n gip ngon ming m cn c tc dng tng cng chuyn ho lm gim lng cholesterol xu trong c th.- Nhng nghin cu cn cho thy dch chit t qu chanh c tnh st khun rt cao. nng 20%, dch chanh c th tiu dit 90% virus HIV.2.2.2. Nc:

2.2.3. ng: - ng l cht kt tinh, khng mu, v ngt, d tan trong nc, nng chy 185oC. c sn xut t ng ma, ng c ci, ng tht nt.- ng saccharoza cha khong 8 -10% trong nc gii kht, c ch bin t cy ma. - ng dng: + Trong cng ngh thc phm: sn xut bnh ko, nc gii kht,+ Trong dc phm: sn xut thuc

2.2.4. Maltodextrin: Sn phm ca Nht, dng bt mn, mu trng, khng mi, tan hon ton trong nc-Ch s D.E ( Dextrose Equivalent) : 15.6 19.5- m : < 6%-pH dung dch : 4.5 -Khi lng ring : 0.59 g/ml-Hm lng ng kh : 1.6 %-Hm lng ng maltose : 5.7 %.-Hm lng trisaccharide : 8 %-Hm lng tetrasaccharide : 5.8 %.-Hm lng polysaccharide : 78.9 %.-Tng s t bo nm mc : < 50 t bo / g-Tng s t bo nm men : < 50 t bo / g2.2.5. Pectinase: - Theo quan im hin i,trong phc h enzyme pectinaza c nhng enzyme sau:+ Pectinesteraza phn ct lin kt este gia methanol v nhm carboxyl ca axit galacturonic theo s :Pectin + nH2O --> metanol + axit pectinic+ Polygalacturonaza thy phn lin kt -1,4-D-galactozit gia cc phn t axit galacturonic trong pectin v trong cc axit polygalacturonic khc+ Protopectinaza tch araban v galactan khi protopectin to thnh dn xut metyl ca axit polygalacturonic(tc l pectin ha tan)+ Transeliminaza phn hy protein bng con ng phi thy phn- Trong sn xut thc phm, ngi ta thng s dng cc ch phm pectinase di dang tinh khit, khng dng ch phm dng canh trng nm mc sy kh. T lng ch phm pectinase c c trn lng nguyn liu em ch bin vo khang 0,03-0,05 n 0,10%.- Trong sn xut nc qu, nh tc dng enzym pectinaza m cc qu trnh p, lm trong v lc dch qu rt d dng. V d a pectinaza vo khu nghin qu s lm tng hiu sut nc qu sau khi p ln 15-25%. Bi khi c pectin th khi qu nghin s c trng thi keo, do khi p khng thot ra han tan c. Nh enzim pectinza phn gii cc cht pectin i m dch qu trong sut, khng b vn c v lc rt d dng. Ngai ra, enzyme pectinaza cn gp phn chit rt cc cht mu, tannin v nhng cht ha tan khc, do lm tng thm cht lng sn phm.- Dng lng mu nu, tn thng mi l PECTINEX 120L. (tn chung ch cc loi enzyme phn hy pectin). iu kin nhit 40ocm thi gian 2-4 gi, pH = 4,52.3. Quy trnh cng ngh sn xut bt chanh:

2.4. Thuyt minh quy trnh cng ngh: 2.4.1. Nguyn liu: Chanh dng trong sn xut bt chanh cn m bo cc yu cu sau:- Lnh ln, ko h hng hay thi ra- Sch s, ko thy s xm nhp ca vt l- Khng b h hng do sinh vt gy ra- Khng c mi hay v l- Cng, chc- Khng b h hng do p sut thp2.4.2. La chn v phn loi:- Mc ch:+ Chn la: nhm loi tr cc nguyn liu a vo ch bin khng qui cch nh su bnh, men mc, thi hng + Phn loi: nhm phn chia thnh nguyn liu ng u v kch thc, hnh dng, mu sc hoc chn cc qu trnh ch bin tip sau c thun li v d c kh ha. - Yu cu: Chanh khng su bnh, thi hng v ng u v kch thc.- Cch thc hin:+ Qu trnh chn la v phn loi c th tin hnh trc khi bo qun nguyn liu, hay trong khi ch bin trong phn xng sn xut. + Vic phn loi bng th cng tn nhiu cng sc, v do th gic hot ng cng thng v lin tc nn cng nhn chng mt mi, thng nh hng khng tt ti cht lng phn loi. Ngi ta c th c gii ha vic la chn v phn loi da trn s khc nhau v kch thc v khi lng ring ca nguyn liu. + y chng ta s s dng my phn c kiu dy cp: b phn phn loi l h thng dy cp cng gia hai trc quay, chuyn ng theo chiu dc ca dy. Khe h gia hai dy cp (qu i gia hai dy cp) to dn v qu s ri dn theo th t t nh n ln.2.4.3. Ra:- Mc ch:+ Loi tr tp cht c hc (t, ct, bi...)+ Lm gim lng vi sinh vt ngoi v nguyn liu.- Yu cu:+ Nguyn liu sau khi ra phi sch, khng b dp nt, cc cht dinh dng t b tn tht, thi gian ra ngn v tn t nc.+ Nc ra cng nh nc dng trong khi ch bin (nh chn, nu, pha ch) phi l nc n, m bo cc ch tiu do Vin v sinh dch y t (B y t) quy nh.- Cch thc hin: Qu trnh ra gm hai giai on: ngm v ra xi. + Ngm lm cho nc thm t nguyn liu, qu trnh ny c tng cng bng tc dng c hc (cnh khuy, c bn chi, thi kh), bng tc dng ty ra ca dung dch kim hoc tng nhit ca nc. Nhng tng nhit v dung cht ty ra th lng cht dinh dng b tn tht nhiu hn. Thi gian ngm ty thuc mc bm bn ca nguyn liu v tc dng ca dung dch ra, c th t vi pht n vi chc pht.+ Ra xi l dng tc dng chy ca dng nc ko cc cht bn cn li trn mt nguyn liu sau khi ngm. Thng dng tia nc phun (p sut 1.96-2.94x105 N/m2 tc l 2-3at) hay hoa sen xi. Nc ra li phi l nc sch, lnh. Thi gian ra li cng nhanh cng tt. nc ra t b nhim bn, ngi ta dng nc ra chy lin tc trong cc b.+ y s dng my ra bi cho: my ny l mt thng ng nc, trong c gn my khuy loi bi cho. Khi my khuy quay nguyn liu di chuyn cng vi nc v c lm sch. Sau h thng hoa sen s trng sch. My ny c hiu qu ra cao.

2.4.4. Bc v bng nhit:- Mc ch:+ Loi b cc phn khng c li ca qu i vi qu trnh sn xut (v xanh cha tinh du, v trng, ht...)+ Gp phn lm gim chi ph v thit b cho qu trnh tip theo.+ Chun b cho qu trnh chn v p.- Yu cu: Tch ht lp v dy n mc c th.- Cch thc hin: Nhng vo nc si T = 90 1000C, thi gian = 20 60 s

2.4.5. Chn:- Mc ch:+ Chun b cho qu trnh p.+ nh ch cc qu trnh sinh ho ca nguyn liu, lm cho mu sc ca nguyn liu khng b xu i. Chn lm ph hy h thng men peroxidase, poliphenoloxydase ngn cn qu trnh oxy ho to thnh flobaphen c mu en.+ Lm thay i th tch khi lng nguyn liu qu trnh ch bin tip theo c thun li.+ ui bt cht kh trong gian bo ca nguyn liu + Lm tng tc thm thu ca cht nguyn sinh, lm cho dch bo thot ra d dng.+ Tiu dit 1 phn vi sinh vt, ch yu l vi sinh vt bm trn b mt nguyn liu.- Cc bin i xy ra+ Gim khi lng, th tch.+ Tn tht vitamin C, cht kh, bc hi nc, mu: ty thuc lng hi nc chn, thi gian v nhit chn.+ V hot enzyme, nh ch hot ng vi sinh vt.- Cch thc hin: s dng thit b chn trc xon nhit khong 75oC

2.4.6. Xay:- Mc ch+ Chun b, gip tng hiu sut cho qu trnh p. Trc khi p, qu c x l c hc (ct, x ti, nghin th). + Hiu qu nghin t c khi phn ln t bo b tc dng, song v kch thc t bo kh nh nn ch mt s nh t bo b ph hy.- Yu cu:+ Kch thc ming x : cng nh cng thu c nhiu dch p.< 0.3 cm3 hiu sut p gim do khi nguyn liu mt xp.> 1 cm3 hiu sut p cng khng cao do t l t bo b ph v thp.+ To iu kin tt cho qu trnh truyn nhit vo nguyn liu (tng h s truyn nhit). Tuy vy nu nghin qu nh, th khi p s khng to thnh rnh thot nc qu, cng lm gim hiu sut p.- Cch thc hin:+ Ct nh hay xay nghin u tc dng c hc thay i hnh dng v kch thc ca nguyn liu, mc ch l chun b cho qu trnh p c d dng. + Li dao l b phn hot ng ch yu ca thit b xay. Cu to li dao gm c hai loi: li phng ct nguyn liu mm, li rng ct nguyn liu cng. + tng hiu sut cho qu trnh p, ngi ta thng dng my nghin dao cong.

2.4.7. p ch:- Mc ch: Khai thc, thu dch qu cn li.- Yu cu:+ Trong qu trnh p, hiu sut p l ch tiu quan trng nht. + Hiu sut p ph thuc vo rt nhiu yu t: phm cht nguyn liu, phng php s ch, cu to, chiu dy, chc ca lp nguyn liu p v p sut p. + Nguyn liu c nhiu dch bo th hiu sut p cao. Qu chn c nhiu dch bo hn qu xanh. Dch bo cha trong khng bo b bao bc bi cht nguyn sinh. Cht nguyn sinh ca cam c tnh bn thm ngn cn s tit dch bo. Mun nng cao hiu sut p phi lm gim tnh bn thm ca cht nguyn sinh bng cch lm bin tnh cht nguyn sinh hay lm cht t bo bng cc phng php ph v cu trc t bo, un nng, s dng ch phm enzyme pectinase. + Trong khi nguyn liu p, cc thnh t vo to ra b khung m gia b khung l nhng ng mao dn cha y dch bo. + Khi p, dch bo s theo ng mao dn m chy ra. Nu cam qu mm, khi p s thnh mt khi c, cc ng mao dn b ph hy v dch bo khng chy ra c. Chiu dy lp nguyn liu p ln th ng mao dn cng d b tc.- Cch thc hin: + y s dng thit b p vi trc p nm ngang.+ p sut p Ban u l 4.9 5.9*106 N/m2(50 60 at).Tng ln 1.96 2.45*107 N/m2 (200 250 at).+ Khi p sut nguyn liu l 8.8 11.7x106 N/m2 (9 12 at).

2.4.8. Lc th:- Mc ch: hon thin dch nc p.- Yu cu: nc qu p c cha cc thnh phn cn t tht qu v cc kt ta th. Phn cn ny c th lc b bng cch lc s b qua lp vi lc. Lp vi lc cng dy, lng cn b loi cng nhiu. - Cch thc hin: Nc qu thng lc p sut khng i v thp (2.7 - 4.9*105 N/m2). Nu p sut trn 4.9*104 N/m2 (0.5at) th cc cn hu c s b kt li lm tc bn lc. to ra p sut, ngi ta bm nc qu vo my lc hay t thng cha nc qu cao hn my lc 3-4 m.

2.4.9. Phi trn: Trong cng ngh sn xut bt chanh ngi ta thng b sung cc loi ph gia sau:- Trong qu trnh ch bin, tanin trong qu thng b oxi ha thnh flobafen c muen. trnh hin tng ny, ngi ta pha ch thm cht chng oxi ha m thng dng nht l acid ascorbic (vit C). Vit C va c tc dng n nh mu sc, va tng gi tr dinh dng cho sn phm. .- Cht mang:+ Maltodextrin : bo v mu mi, lm cht n.+ Protein : to vi bao.- Ngoi ra cn b sung thm mu thc phm tng gi tr cm quan cho sn phm, ng thi gip sn phm khng b nht mu trong qu trnh bo qun.- Cch thc hin: qu trnh phi ch c thc hin trong cc thng phi ch chuyn dng c cnh khuy trn u.+ Tng nguyn liu ph s c chun b theo quy trnh ring. + i vi cht mu, hng liu, cht c ch vi sinh vt chng ta cng thc hin tng t nh trn. Mi thnh phn nguyn liu s c chun b trong mt thit b ring. Cn lu l khi s dng cht mu dng bt, ngi ta s ha tan vo nc to thnh dung dch mu c nng dao ng trong khong 20 50%.+ Thng thng, tng th tch cc dung dch acid, cht mu, hng liu, cht c ch vi sinh vt chim xp x 8% tng th tch ca thnh phm.

2.4.10. C c:- Mc ch: Tch bt nc ra khi dch phi trn tit kim chi ph nng lng cho qu trnh sy tip sau.- Tc dng:+ Loi b mi l trong sn phm.+ Hn ch qu trnh oxi ho.+ Hn ch s pht trin ca vi sinh vt hiu kh.+ Hn ch hin tng n mn hp st.- Cc yu t nh hng:+ Nhit hn hp: nhit cng cao, cc cht kh dng phn tn ho tan v cc cu t d bay hi cng d thot ra khi hn hp. Tuy nhin, nhit qu cao s xy ra 1 bin i khng c li nh hng xu n cht lng sn phm nh 1 s vitamin b phn hy, c bit l vitamin C c trong nguyn liu+ p lc chn khng: nu p lc chn khng qu ln, mt phn hi nc ngng t s b tch theo cc kh, l chi ph nng lng tng.- Yu cu: Hm lng cht kh sau qu trnh c c khong 45 55%

3.2.11. ng ha:L phng php lm cho sn phm lng hoc c c ng nht bng cch lm cho phn t ca sn phm c kch thc rt nh (phn ln l ti vi chc micromet). Sn phm qua ng ha th tng gi tr mi v, mn, tiu ha, v lm gim s phn lp sau ny.- Mc ch:+ Ph v, lm gim kch thc ht, phn b u cc pha trong ht.+ Gip cho hn hp tr nn ng nht hn.+ Nguyn tc ng ha: ng ho bng phng php s dng p lc cao, da vo 3 nguyn l: thuyt vi xoy, thuyt xm thc kh, s va p.- Cc bin i xy ra:+ Vt l:S thay i kch thc tht qu: Tht qu b chia nh, gim kch thc.S thay i nhit : nhit tng ln do ma st.+ Ho l:S phn b phn tht qu trong dch hn hp ng nht hn.Lm tng din tch b mt tip xc pha, lm bn h nh tng.- Cc yu t nh hng:+ Nng cht ca tht qu trong hn hp: Nu h huyn ph c t l phn tht qu thp th h bn hn.+ Nhit : nhit cao qu trnh ng ho cng hiu qu hn, tuy nhin nhit cao chi ph nng lng ln. ng thi xy ra cc phn ng ho hc khng mong mun.+ p sut: p sut ng ho cng ln, hin tng chy ri v xm thc kh s cng d xut hin, do kch thc ht phn tn s b chia nh v h huyn ph thu c c bn cao.- Cch thc hin:+ ng ho tin hnh sau khi ch hoc nghin.+ Phng php s dng p sut cao: ng ha 1 giai on.+ Thit b: Dng thit b ng ho s dng p lc cao: gm bm cao p v h thng to i p.

3.2.12. Sy phun:- L qu trnh lm bc hi nc ra khi vt liu di tc dng ca nhit. Trong qu trnh sy, nc c tch ra khi vt liu nh s khuch tn do:+ Chnh lch m gia b mt v bn trong vt liu.+ Chnh lch p sut hi ring phn ca nc ti b mt vt liu v mi trng xung quanh.- Cc yu t nh hng:+ Nng cht kh trong dung dchCng cao th cng tit kim thi gian sy v nng lng cn cung cp.Tuy nhin, nu qu cao s lm tng nht gy kh khn cho qu trnh to sng m trong bung sy, c cu phun d b tc ngn hoc to ht vi hnh dng v kch thc khng nh mong mun.Thng khong 45 52%.+ Nhit tc nhn syNhit cao qu trnh sy phun cng hiu qu hn.Tuy nhin nhit qu cao m cui ca bt sn phm s khng gim thm nhiu. Hn na, ph hy cu t mn cm nhit, tn km nng lng.+ Kch thc, s lng v qu o chuyn ng ca cc ht nguyn liu trong bung sy.- u im:+ Tn tht cht dinh dng khng ng k.+ Sn phm c hnh dng v kch thc tng i ng nht.+ Nng sut cao, lm vic theo nguyn tc lin tuc.- Nhc im:+ Khng th s dng mu c nht qu cao, vn u t thit b ln.+ Thit b thng c thit k cho sn phm c tnh cht v c th ring.- Cch thc hin:

- Thng s cng ngh:+ Giai on 1 : 75% lng tc nhn sy (270 2800C) c np vo vi phun, 25% cn li (100 1500C) c np qua li phn b Sn phm ri xung bng ti, W = 6 -14%+ Giai on 2 : bng ti a sn phm qua bung sy ph, tc nhn sy trn ng thot qua bng ti tip tc tch m sn phm W = 3 10%+ Giai on 3 : np tc nhn sy mi (110 1400C) sn phm t m yu cu, kh thot 74 760C. Sau cng, bng ti a sn phm vo bung lm ngui (khng kh tch m, 15 200C).3.2.13. Hon thin:- Mc ch+ Ci thin mi v.+ Tng kh nng ha tan ca bt sn phm.- Cch thc hin + S dng ng bt tng kh nng phn tn ca sn phm.+ Qu trnh to ht.Ht sn phm sau sy phun s c lm m tr li qu trnh kt dnh gia chng to nn nhng khi ht mi.Tip theo, cc khi ht ny s c sy tch m v lm ngui kch thc ht tng t 30 80m ln 150 200m.3.2.14. Bao gi: - Vt liu bao b: thng s dng bao b kim loi hoc bao b giy ng sn phm.- Yu cu k thut: hn ch tip xc vi nh sng, khng kh v m t mi trng xung quanh n bt tri cy.2.5. Ch tiu cht lng sn phm:- Sn phm bt chanh thu c c cu trc mn. - m thp (