I. Gii thiuCho n lin l mt thc phm n lin tc l c th s dng ngay m khng cn qua ch bin phc tp, do thc phm n lin phi qua khu ch bin nhit trc khi c ng gi. Cho n lin l sn phm lm t go c nu chn v lm n bng cch p n. Sn phm s km theo cc gi gia v, ty theo yu cu ca nh sn xut m chng ta c cc loi cho c nhiu hng v khc nhau (cho g, heo, b, c)2. Tng quan v nguyn liu2.1 Bt goNguyn liu chnh sn xut cho n lin l go, nguyn liu ph l nc. Bn cnh cn c cc ph gia nh: CMC (cacboxyl methyl cellulose), natri polyphosphat, bt mu thc phm v mui n, du c tinh luyn, cht iu v, hnh tiu2.1.1 Cu toGo l mt sn phm lng thc v cha nhiu cht dinh dng.+ Go lc (go lt): l loi go ch c loi b v tru m cha qua qu trnh ch trng, v vy go c mu nu to lp cm bn ngoi ca ht go, lp cm ny giu khong v Vitamin, c bit l Vitamin nhm B. + Go xt (go gi): l loi go c loi b c phn v tru v lp cm bng cch em gi hoc xt go lt. y l loi go ta thng dng v chn lm nguyn liu nu cm hoc ch bin thnh cc sn phm t go, bn, bnh trng. V ht: Pha trong v qu l v ht. V ht lin kt cht ch vi lp aleurone.-Lp Aleurone v ni nh Lp aleurone: Bn trong lp v l lp aleurone bao bc ni nh v phi chim khong 6 12% khi lng ht. T bo lp aleurone l lp cc t bo ln, thnh dy hnh khi ch nht hay vung c kch thc nh dn v pha phi. Trong t bo lp aleurone c cha nhiu protid, tinh bt, cellulose, pentosan, cc git lipid v phn ln cc vitamin v khong ca ht. V vy trong qu trnh ch bin ht, khng nn xay xt qu k gi li cc vitamin v khong cht. Ni nh ch yu l tinh bt v protid, ngoi ra cn cha mt lng nh lipid, mui khong, cellulose v mt s sn phm phn gii ca tinh bt nh dextrin, ng- Phi Khi ht ny mm th phi s pht trin ln thnh cy con, v vy trong phi cha nhiu cc cht dinh dng cn thit cho s pht trin ban u. Thnh phn ha hc ca phi gm c protid, glucid ho tan, kh nhiu lipid, khong, cellulose v cc vitamin. Phi cch ni nh bi lp ng l lp trung gian chuyn cc cht dinh dng t ni nh sang phi khi ht ny mm. 2.2 Thnh phn ha hc:

2.2.1 GlucidGlucid l thnh phn ch yu v chim t l cao nht trong thnh phn ht go. Cc glucid ca go ngoi tinh bt l thnh phn ch yu cn c ng, cellulose, hemicellulose, dextrin.ng trong go gm c glucose, saccarose, fructose, rafinose v maltose.Cellulose v hemicellulose l nhng glucid m c th ngi khng th tiu ha c. Cellulose ch yu c trong lp v aleuron.Tinh bt go thuc loi tinh bt phc tp, kch tht rt nh, c th ni nh nht trong cc tinh bt ng cc.

Hnh 1: Hnh nh ht tinh bt go, bp, khoai ty.Ht tinh bt thng c kch tht 4-7 micromet, cc ht tinh bt sp xp khng th t, gia cc ht tinh bt vi nhau c cc khe h ln v bn cnh cc ht tinh bt a gc cnh c lc c nhng ht trn hay bu dc. S sp xp cng nh s phn b kch thc ca ht tinh bt trong nhng ging go khc nhau khng c s khc bit ng k.

Hnh 2: Cu trc ca ht tinh bt goTinh bt tn ti di hai dng l amilo v amilopectin c t l thay i ph thuc vo ging la. Go t c hm lng amilopectin trong khong 11 n 35%.

Hnh 3: Cu trc amilo v amilopectin

+AmylosePhn t amylo c cu to mch thng gm nhng n v mch thng -glucose kt hp vi nhau bng lin kt 1,4-glucozit, mch cun xon c, mi n v vng xon c 6 n v glucose.Amylo d ha tan trong nc m to thnh dung dch c nht khng cao. Khi nhit dung dch h thp, amylo d b thoi ha, to ra gel tinh th v cc kt ta khng thun nghch. Dung dch c nu chn s to cc phc hp amylose, bo v mt phn khi s thoi ha.+AmylopectinPhn t amylopectin c cu trc phn nhnh do cc gc -glucose kt hp vi nhau bng lin kt 1,4-glucozit v lin kt 1,6-glucozit ti cc im phn nhnh.Amylopectin ch ha tan trong nc nng v to dung dch c nht cao. Do cu trc cng knh lp th nn cc phn t amilopectin khng c khuynh hng kt tinh li, v vy dung dch amylopectin thng khng b hin tng thoi ha.2.2.2 ProteinProtein c hm lng t 6.6 n 10.4%, ty thuc vo ging, iu kin chm sc. Protein ca la ch yu gm ba loi chnh:+Globulin: Ch yu phn b cc lp v, do c nhiu trong cm hn go.Glutenlin: Tp trung phn ngoi, ni nh.Albumin: c rt t, tp trung ch yu phn mm.

Bng 2: Hm lng protein ch yu ca la, go xt, cm2.2.3 LipitLipit l thnh phn dinh dng quan trng mc d hm lng lipt trong thc ch chim khong 2%.Lipit cha cc axit bo cha no, cht bo trong ht d b thy phn di tc dng ca kim. Trong qu trnh bo qun, di tc dng ca enzim lipase c trong ht, qu trnh thy phn cht bo thnh glycerin v axit bo t do cng xy ra.Cht bo trong ht la ch yu tp trung phi v lp aleuron. Trong thnh phn ca cht bo ca la c ba acid chnh, l acid oleic, linolic v palmitic. Cc acid bo khc nh a. stearic, miristic, arakhic, linosteric c hm lng rt nh. Ngoi ra trong cht bo ca la cn c mt lng lizolixitin v photpho.

Bng 3: Thnh phn lipt trong cc phn ca ht la2.2.4 VitaminTrong go c cc loi vitamin sau y: B1, B2,B6, PP, E, B12phn ln tp trung phi, v ht, v lp aleron. Go hu nh khng c hoc c rt t vitamin A, C, D. Trong ni nh c cha vitamin vi t l thp, do go sau xay st thng c hm lng vitamin rt nh do b tch ra theom cm. Go cng xt k th hm lng vitamin b tn tht cng nhiu.2.2.5 Cht KhongHm lng khong chu nh hng ca iu kin trng trt. Trong ht la hm lng Si l nhiu nht. Trong go lt v go xt, P l ch yu, bn cnh trong go cng c nhiu K, Mg, Si.Hm lng khong trong ht go c khuynh hng gimn vo trong ni nh. Ni nh cha t cht khong hn phi v lp cm bn ngoi.

Bng 4: Phn b hm lng khong trong cc phn ca ht la2.2.6 Gi tr dinh dng ca la go

Bng 5: Thnh phn trung bnh ca ht go xt cho 100g n cSo vi cc loi ng cc khc, go c hm lng protein v cht x thp nht, hm lng cacbohydrat mc trung bnh. Cc loi ng cc khc nhau ch yu thnh phn lipid nhng nhn chung hm lng lipid trong ng cc u mc thp. Hm lng vitamin trong ng cc cng thp hn cc loi thc n c ngun gc thc vt khc.

Bng 6: Gi tr dinh dng ca go so vi cc loi ng cc khcTuy hm lng protein thp nhng cht lng protein ca go cao hn hn cc loi ng cc khc. iu ny th hin gi tr sinh hc ca protein v kh nng hp thu protein ca c th (NPU) ca go u c gi tr cao. Ngoi ra t l hp thu nng lng t go cng t gi tr cao nht, u ny cho thy go l thc n giu dinh dng.

Bng 7: T l hp thu nng lng ca go so vi cc loi ng cc khc2.3 Ch tiu cht lng ca go trng:

Bng 8: Phn loi cc tiu chun ca ht go

Bng 9: Ch tiu cht lng ca go trng (khng ln hn % khi lng)

Bng 10: Yu cu cht lng i vi go

Bng 11: Liu lng s dng cho php ca cc ha cht trong go trng.2.4 Yu cu ca ht go dng trong sn xut cho n linHin nay cng ngh ch bin go ca nc ta cn kh th s v phng thc ch bin ch yu l th cng, quy m nh. Do tnh trng s dng nguyn liu v quy trnh ch bin ty tin nn nng sut v cht lng sn phm khng n nh, mu m cha hp dn, thm ch cn cha m bo v sinh nn kh nng cnh tranh cha cao. ngnh sn xut la go pht trin hn na p ng nhu cu ngy cng cao ca th trng vic ch bin la go thnh cc sn phm hng ha l rt cn thit. Vi mc tiu , cc phng php ch bin go truyn thng ca nc ta hin nay cn c cng nghip ha, tiu chun ha t khu la chn nguyn liu n quy trnh v dy chuyn cng ngh sn xut. Vic tm hiu cc loi go, cc c tnh cht lng s dng trong ch bin c ngha quan trng.

Bng 12: Cc loi go hin nay ca nc taGo s dng ch bin cho gm 7 ging: CR203, DT10, Mc Tuyn, 13/2 (IR17494), VN10, Khang Dn, C70. Go trong ch bin cho c xay xt t thc c l loi thc sau khi thu hoch c thi gian lu kho t nht t 6 thng n 1 nm thun li cho qu trnh gia cng d dng, sn phm c cht lng n nh. Bn cnh la chn go th cc khu trong qu trnh ch bin cng quyt nh rt ln n cht lng cho. Cn la chn loi go t tt v phi m bo yu cu:+Go t ngon+Khng c mi mc+Khng c su mt.+T l tp cht di 0.1%.2.5 Tnh cht cng ngh ca go dng trong sn xut cho n lin:2.5.1 Hin tng h ha tinh bt bng nhit nng:Khi hp th nc tinh bt trng n dn, khi tng nhit n mt gii hn no , cc ht tinh bt trng n mt cch nhanh chng, hnh dng cc ht tinh bt s thay i t ngt to thnh dng keo dnh. Hin tng trng n xy ra trc tin cc khe lm ca cc ht tinh bt, sau lan rng ra c b mt lm cho th tch ca chng tng ln nhiu ln cho n khi ht tinh bt b rch v tr thnh ci ti khng nh hnh, hoc ngng tng th tch, lc tinh bt bt u h ha, nhit tng ng tinh bt bt u h ha gi l nhit h ha. Bng 13: Nhit h ha v bn gel ca mt s loi go nhit thng cc phn t nc lin kt vi nhau thng qua ni hydro. Do kh nng hot ng ca chng khng cao. Khi c un nng nhit nng cung cp s ph v hng lot lin kt hydro rng buc cc phn t nc, gip chng t do hot ng nn chng linh hot hn rt nhiu, d dng tn cng vo cu trc micell ca ht tinh bt, gy nn s hydro ha, nhng vng c h ha u tin l vng v nh hnh ca mng li micell, ti lin kt tinh bt yu hn nhng vng c cu trc tinh th, do vy lin kt hydro gia cc phn t tinh bt nhng vng d b phn hy, gip cho hin tng hydro ha d dng.Mt khc nhit cao cng ph hy cc lin kt hydro gia cc phn t tinh bt gip cho cc phn t nc d b hydrat ha. Trong qu trnh h ha c mt s phn t tinh bt b hydrat ha mnh m s tch khi mng li micell, khuch tn vo mi trng nc gy nn hin tng ho tan tinh bt vo nc nng.Nh vy nhit h ha v kh nng h ha ca mt loi tinh bt no s ph thuc rt ln vo cu trc mng li micell trong ht tinh bt, cu trc ny c t trng bi hnh dng, kch tht phn t, khi lng phn t, t l gia amylo v amylopectin, mc phn nhnh v chiu di ca nhnh amylopectin. Thng thng cu trc ca mng li micell khng n nh, nn qu trnh h ha khng xy ra mt nhit nht nh m dao ng trong mt khong nhit t 8 n 100C, cung cp thm nng lng cho s ph v lin kt nhng vng c cu trc cht ch trong mng li micell to nn lin kt mi gia tinh bt v nc.Qu trnh h ha cc loi tinh bt thng xy ra nhit nh hn nhit si ca nc. Nu sau khi h ha xong m qu trnh gia nhit vn ko di cho n nhit si, th nng lng c cung cp tha do gia nhit li tip tc ph hy lin kt hydro va mi to ra gia phn t nc v cc nhm OH ca tinh bt, lm cho kt cu ca tinh bt h ha tr nn lng lo. Gim nht, do ca h tinh bt. 2.5.2 Hin tng thoi ha ca h tinh btKhi gel tinh bt mt thi gian di, cc phn t tinh bt s co li v kt tinh, nc s tch ra dng t do. Qu trinh ny cng tng mnh nu gel nhit lnh ng ri sau tan gi. Cc hin tng thoi ha l do hnh thnh nhiu cu hydro gia cc tinh bt. Cc phn t amylo c mch thng nn nh hng vi nhau d dng v t do hn cc phn t amylopectin. V th hin tng thoi ha gn nh ch c lin quan n cc phn t amylo l ch yu. C nhiu yu t bn ngoi nh hng n tc thoi ha nh: nhit , pH, s tn ti cc mui v c. Nhit cng tng, tc thoi ha cng gim, bi v khi nhit thp lm cho lin kt hydro gia cc phn t nc cng bn hn, ngc li lin kt hydro gia tinh bt vi nc cng yu hn. pH ca mi trng cng nh hng r rt n tc thoi ha tinh bt. Kt qu nghin cu cho thy pH=7 th tc thoi ha cc i, pH ln hn hay nh hn, tc thoi ha s gim i. Khi pH=10 hoc pH=12 rt t xy ra hin tng thoi ha. Khi thm mt s mui v c vo h tinh bt in hnh l MgSO4 s lm tng tc thoi ha.S thoi ha gm 3 giai on:+u tin cc mch c un li.+Tip n v hydrat b mt v cc mch c nh hng.+Cc cu hydro c to thnh gia cc nhm OH trong phn t amylose. 2.2 Nguyn liu ph2.2.1 NcNc dng trong sn xut cho n lin phi m bo ng tiu chun ca nc dng trong thc phm, ngha l phi t cc yu cu c th nh sau:

Bng 13: Ch tiu cht lng ca nc (TCVN 5502:2003)2.2.2 Du c tinh luyn

Bng: Ch tiu cht lng ca du c tinh luyn (TCVN 6048:1995)2.2.3 Gia v2.2.3.1 ngng s dng l ng ct trng, kh, ti, tinh th ng u, ha tan hon ton trong nc, v ngt, khng c v l, khng c tp cht.ng c tc dng to v ngt cho sn phm. Ngoi ra ng cn l cht ph gia, gim bt hot tnh ca nc, chng lin kt vi phn t nc bng lin kt hydro hay ion, bin nc t do thnh nc lin kt, v vy sn phm s tng bn vng i vi cc loi vi sinh vt khi bo qun v do sn phm c hm lng nc cao, cu trc sn phm s tr nn mm du hn. S to thnh cc cht kh trong qu trnh ch bin gp phn to mu cho sn phm.2.2.3.2 MuiMui s dng trong ch bin l mui n phi nc tun theo tiu chun TCVN 3974-84 v t nhng tiu chun sau: Chn mui tinh khit, tinh th mu trng u, sch, khng c tp cht, khng c v l, m khng qu 12%, khi ha tan trong nc ct nhn c dung dch trong v ng nht. Ngoi cng dng to v cho thc n, mui n cn c ch vi sinh vt khi c nng cao, bi v khi nng mui trong sn phm tng ln th lng nc t do trong mi trng gim i, vi sinh vt kh tn ti v pht trin.

Bng: Ch tiu cm quan ca mui n (TCVN 3974-84)

Bng: Ch tiu ha l ca mui n (TCVN 3974-84)2.2.3.3 Du nDu thc vt l loi du c chit xut, chng ct v tinh ch t thc vt.Cng dng: Cung cp ngun nng lng cn thit cho c th, thch hp cho chin, xo, lm bnh, v cho ngi n chay.2.2.3.4 Tiu btC 2 loi ht tiu: l ht tiu en v tiu trng. Mi v ca hai loi tiu ny c mt cht khc bit: ht tiu trng hng v hi nht, nhng c v cay m, c th kt hp vi nu tht, xo rau.Ht tiu en li c hng v m , c tc dng iu v, lm cho chng ta n cng thm ngon ming, ch yu l cc ht tiu en nu hoc kho cc mn tht, c bit l tht b.

Bng: Ch tiu vt l ca ht tiu (TCVN 7036-2008)

Bng: Ch tiu ha hc ca ht tiu en (TCVN 7036-2008)2.2.3.5 Bt ngtM t: Bt kt tinh trng khng dnh vo nhau, ri rc, khng mi, d tan trong nc, tan va phi trong cn. MSG va c v ngt hoc hi mn. pH ca dung dch mu c t l 1/20 gia 6,7 v 7,2.Chc nng s dng trong thc phm: Tng v umamiMonosodium Glutamate l mt loi ph gia thc phm c tc dng iu v lm cho thc phm ngon v hp dn hn.Bt ngt hin nay c lm t nguyn liu thin nhin nh tinh bt sn v mt ma ng bng phng php ln men, mt qu trnh tng t nh sn xut bia, gim, nc tng.

Bng: Ch tiu cht lng ca bt ngt (TCVN 1459-1996)3. Quy trnh cng ngh3.1 Quy trnh

3.2 Thuyt minh quy trnh3.2.1 Lm sch3.2.1.1 Mc ch: Mc ch chnh ca lm sch l chun b. Loi cc tp cht l mt trong cc mi nguy nh hng n sc khe ca con ngi hoc n tnh cht cm quan ca sn phm.Loi cc tp cht gip kim sot vi sinh vt, cc thnh phn ha hc ca nguyn liu, t kim sot c cc phn ng sinh ha trong nguyn liu, hn ch n mc thp nht cc tc ng xu n hiu qu ca sn xut cng nh cht lng sn phm.Mt qu trnh lm sch phi tha mn cc yu cu sau:-m bo v hiu qu ca qu trnh phn ring, sao cho lng tp cht b loi ra l nhiu nht, ng thi, lng tn tht nguyn liu l thp nht.-m bo yu cu v s ti nhim bn: tp cht sau khi c phn ring phi c tch ri hon ton khi nguyn liu, chng khng th i vo nguyn liu tr li.-Qu trnh v thit b phi c thit k hn ch hin tng ti nhim bn tr li i vi thc phm c lm sch nh bi hay nc thi.-Hn ch n mc thp nht s pht sinh ra dng cht lng (c bit l nc thi). Cc dng thi ny cng ln th nguy c ti nhim cng cao (v ngun thi dng lng thng kh kim sot hn dng rn) v cn chi ph x l ln.Qu trnh lm sch s lm cho tnh cht ca nguyn liu t yu cu ca quy trnh cng ngh sn xut nhm m bo quy trnh sn xut c vn hnh tt v sn phm thu c c cht lng t yu cu.3.2.1.2 Cc bin i ca nguyn liuCc bin i chnh trong qu trnh lm sch hon ton ph thuc vo tng phng php lm sch, mang tnh cht c trng tng phng php. Nguyn liu sau khi lm sch nn a vo quy trnh sn xut ngay hn ch hin tng ti nhim.Tnh cht vt l: Gim lng tp cht (bi, t), c trong nguyn liu.Nhit nguyn liu gim.Do c s ht nc vo trong nguyn liu nn lm thay i t trng ca nguyn liu.Bin i sinh hc: Gim mt vi sinh vt nhim trn nguyn liu do s ra tri vi sinh vt bm trn b mt nguyn liu.Bin i ha l: Trong qu trnh ra, c th xy ra qu trnh ha tan mt s cht tan vo trong nguyn liu: vitamin, khongng thi c s ht nc vo trong nguyn liu.Bin i ha sinh: Cc bin i ha sinh hu nh khng xy ra.

3.2.1.3 Cc yu t nh hngTrong tt c cc qu trnh lm sch, vn cn quan tm nhiu nht l tnh cht ca nguyn liu, c bit l tnh cht b mt. Ph thuc vo tnh cht c trng ca nguyn liu, ta mi c th la chn phng php lm sch ph hp. Bn cnh , tnh cht v trng thi ca tp cht cng c nh hng quyt nh n qu trnh lm sch nh tp cht, kch thc, t trngCht lng nc v nhit nc ra: Nc dng ra phi qua x l v t tiu chun cng ngh. Nhit nc ra cng nh hng n qu trnh ra. Nhit cao gip qu trnh tch cc tp cht ra khi nguyn liu d dng hn ng thi c tc dng c ch vi sinh vt nhng ko theo n l chi ph v nng lng, thit b v cc yu t khc.3.2.1.4 Thit b v thng s cng nghS dng thit b ra xi: Thit b c cu to l cc bn inox hnh tr, y cn. Bn trong c h thng vi phun nc gip tng hiu qu lm sch lp tp cht bm trn b mt go. Nguyn tc ca phng php l phun nc ln nguyn liu vi mt p lc nht nh. Di tc dng ca lc nc, cht bn s c tch ra v i theo dng nc. Hiu qu ca phng php ny ph thuc vo cc yu t nh: p sut nc, lng nc s dng, nhit nc, thi gian lm sch. p sut nc cng cao, hiu qu lm sch cng tng, nhng mc tn thng nguyn liu cng tng cao. Thng s cng ngh:Nhit nc ra: 20-25oCp sut nc ra:3.2.2 Lm m3.2.2.1 Mc ch: Qu trnh lm m lm tng nguyn liu n mt m nht nh, ht go tr nn mm hn, chun b cho qu trnh p n.3.2.2.2 Cc bin i ca nguyn liu:ngay hn ch hin tng ti nhim.Tnh cht vt l: Nhit nguyn liu gim.Do c s ht nc vo trong nguyn liu nn lm thay i t trng ca nguyn liu.Bin i sinh hc: Qu trnh bin i sinh hc hu nh khng xy ra do hu ht vi sinh vt c loi i trong qu trnh ra xi.Bin i ha l: Trong qu trnh ra, c th xy ra qu trnh ha tan mt s cht tan vo trong nguyn liu: vitamin, khongng thi c s ht nc vo trong nguyn liu. Qu trnh bay hi mt s tp cht mi cng c th xy ra di tc dng ca nhit .Bin i ha sinh: Cc bin i ha sinh hu nh khng xy ra.3.2.2.3 Cc yu t nh hng:Nhit v thi gian: Nu nhit qu cao v thi gian qu di s xy ra cc phn ng ha hc khng mong mun, bn cnh , s tn tht cc cu t mn cm vi nhit gia tng, cc gi tr lin quan n cu trc, mu sc v mi v ca nguyn liu s b bin i theo chiu hng khng mong mun, ng thi cn lin quan n nhng chi ph v nng lng. Nu thi gian v nhit thp c th khng to c m thch hp cho qu trnh p n, khng to c gi tr sn phm mong mun.Bn cht nguyn liu: Ty vo cu trc v lin kt gia cc thnh phn ty thuc vo tng loi go nguyn liu m nh hng n kh nng ht m ca chng.3.2.2.4 Thit b v thng s cng ngh:Thit b: S dng b ngm ht, lm bng thp khng r, c th c lp v o gi nhit.Thng s cng ngh:+Nhit : 60-700C+Thi gian: 20-30 pht+ m nguyn liu khi kt thc qu trnh: 18-21%3.2.3 p n3.2.3.1 Mc ch cng ngh:Ngoi mc ch chnh l hon thin-to hnh cho sn phm, p n p lc cao c c kh nng p ng c nhiu mc ch cng ngh khc.Trc ht, do cu to ca trc vis, qu trnh c th vn chuyn, phi trn hay nho trn nguyn liu vi nhau. Sau , khi nhit tng s gip thc hin cc qu trnh lm chn sn phm nh bin tnh protein, h ha tinh bt v to ra mi v, mu sc do phn ng Maillard. Trong nhng trng hp ny, qu trnh p n c mc ch cng ngh l ch bin. Nu nhit nguyn liu trong qu trnh tng cao hn 1000C, nc s bc hi khi thot ra ngoi l khun v lm gim m ca sn phm. Nhit cao cng lm v hot enzym v tiu dit vi sinh vt nn qu trnh p n p lc cao cn c mc ch bo qun.3.2.3.2 Cc bin i ca nguyn liu:Khi nguyn liu c nhp vo trong thit b, dc theo chiu di my c th tri qua ba giai on: Giai on phi trn, giai on nho trn v giai on nu-nh hnh. Mi giai on ny c cc bin i khc nhau ca nguyn liu. +Giai on phi trn l giai on u khi nguyn liu mi nhp vo trong thit b. vng ny ng knh trc vis thng nh hay bc vis tha, tc l khng gian cha nguyn liu nhiu. p lc v nhit cha cao nn cu trc ca nguyn liu khng c bin i no ng k. Bin i chnh trong qu trnh u tin l s phi trn u cc nguyn liu vi nhau.+Khi nguyn liu c y tip qua vng th hai, nhit v p sut tng dn cng nh cc cu t, nht l nc c trn u, khuch tn vo cu trc bn trong nguyn liu, hnh thnh cc lin kt hidro gia nc v cc phn t c cha nhm ho nc nh protein, pentosane, tinh bt Nguyn liu trng n ln, mt s phn t d tan s khuch tn ra ngoi mi trng lng. Khi bt tr nn c hn. Giai on ny c gi l giai on nho trn.+Khi nguyn liu c y vo vng th ba, vng khng gian dnh cho nguyn liu rt t, nguyn liu b dn nn to nn p sut v nhit cao, y l giai on nguyn liu b bin i su sc nht. Di p lc cao, cc lc c hc tc dng ln nguyn liu theo hai hng ngc nhau c tc dng ph v cu trc ht tinh bt hay x rch b si protein. Mc ph hy ny ty thuc vo ln ca lc ct do trc vis tc dng ln khi nguyn liu. ng thi ty thuc mc tng cao ca nhit s lm tng chuyn ng nhit ca cc phn t. Cc chuyn ng nhit hn lon ny c khuynh hng ph v cu trc bc 3, lm bin tnh protein. i vi tinh bt, chuyn ng nhit ln cng vi s c mt ca nc gip tch ri cc phn t tinh bt v chuyn chng thnh dng dung dch, thc hin qu trnh h ha ht tinh bt. Cc bin i ny lm cho khi nguyn liu thay i t trng thi ht ri thnh trng thi chy do. trng thi ny, cc phn t linh ng hn, c khuynh hng dui mch, to ra cc lin kt mi, c bit l thng qua cu ni ca lin kt hidro gia cc phn t nhau to thnh khung mng cho sn phm sau ny. Cc phn t kh v hi nc c phn b u gia cc khung mng chnh l cc mm kh to xp cui cng cho sn phm.