TRNG I HC BCH KHOA I HC QUC GIA TP HCM

H THNG PROTEIN THC PHM

TRNG I HC BCH KHOA I HC QUC GIA TP HCM

KHOA CNG NGH HA HC

B MN CNG NGH HA THC PHM

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BI BO CO

H THNG PROTEIN THC PHMCBGD : Trn Th Bch Lam

Nhm - lp HC05TP2

MC LC

3I.Gii thiu chung.

3II.Cc h thng protein thc phm.

31.H thng protein ca tht, c.

3Gi tr dinh dng.

4nh hng ca cc iu kin cng ngh n protein ca c.

4nh hng ca nhit .

5nh hng ca lnh ng.

6nh hng ca s kh nc

72.H thng protein ca trng.

7Protein ca lng trng trng.

7Thnh phn dinh dng

8Cc bin i khi bo qun.

8Protein ca lng trng.

9Thnh phn.

9Cc bin i trong bo qun.

103.H thng protein ca sa.

10c im v gi tr dinh dng.

10nh hng ca cc qu trnh x l cng ngh.

11Hiu qu ca gia nhit.

11Hiu qu x l lnh.

124.H thng protein ca mu.

12Thnh phn v s phn on mu.

13Mt s protein c trong mu.

13Cc yu t nh hng.

145.H thng protein ca ng cc.

14Protein ca la m.

14Thnh phn.

16Cc bin i khi bo qun.

17Protein ca u tng.

17Thnh phn.

17S to gel.

I. Gii thiu chung. Protein l mt trong nhng thnh phn quan trng ca thc phm cung cp nhng tin cht cho qu trnh sinh tng hp protein ca c th. Trong qu trnh ch bin thc phm, n trc tip to nn hng v ca sn phm cng nh tham gia vo cc phn ng to mu mi

Ngun cung cp protein rt a dng v phong ph. Ngoi nhng ngun protein truyn thng nh : tht c trng sa, ng cc v rau qu th hin nay ngi ang ch n vic khai thc cc ngun protein phi truyn thng nh : cc loi to, nm men v cc cht thi t l m c bit l tit v xng.II. Cc h thng protein thc phm.1. H thng protein ca tht, c. Gi tr dinh dng. Tht l mt trong nhng loi thc phm c gi tr dinh dng cao. Tht cc ng vt mu nng nh tht ln, tht b, tht gia cm c cha nhiu axit amin cn thit, cc cht bo, cht khong, vitamin v mt s cht khc gi l chit xut tht. Thnh phn protein trong mt s loi tht.

Tn thc phm Nng lng

(kcal) Protein

(mg %) nc

(mg %) lipid

(mg %)

Tht b nc8520720.5

Tht b1182174.13.8

Tht tru12122.8733.3

Tht ln13919737

Tht d12220.774.44.3

Tht g19920.365.613.1

Tht vt26717.859.521.8

H thng protein ca tht l nhng t c trong c cha t 15-20% protein ngha l chim t 50-95% cht hu c ca tht. Gi tr sinh hc protein tht l 74%, ng ha l 96-97%. Da vo v tr c th phn chia protein c thnh 3 nhm :

- Protein ca cht c.

- Protein ca m lin kt.

- Protein ca t c.

nh hng ca cc iu kin cng ngh n protein ca c.

nh hng ca nhit . Hu ht cc protein b bin tnh v to ra cc tp hp nhit 45-60oC. Mioglobin b bin tnh khin cho tht b bin t sang nu xm do to ra sc t firihemocrom.

Ti 50oC tht vn gi c mu sc, gia 50oC v 70oC tht trng ra v cho tht mu , trn 70oC tht c mu nu do Mioglobin b bin tnh.

Vi calogen th trong qu trnh gia nhit n 55oC phn t b co ngn i 1/3. n 61oC th b co ngn i mt na. nhit gn 100oC th calogen b ha tan v to ra gelatin. Gelatin c c im l chu lc ct km nhng kh nng gi nc rt tt.

Elastin hu nh khng b tc dng bi cc enzym phn gii protein cng nh khng bin i trong qu trnh nu do c th khng hp thu m thng thi ra nguyn vn. nhit 100oC v c nc th elastin cng ch b trng ra m thi.

Calogen v elastin l hai loi protein kh hp thu, gi tr dinh dng thp v trong thnh phn hu nh khng c tryptophan v xystin l hai axitamin c gi tr cao. Trong qu trnh nu nng, mt lng chit xut tan trong nc, d bay hi, c mi v thm c bit. Chit xut gm c creatin creatinin , carnosin ( c nit )v glycogen, glucoza , axit lactic ( khng c nit ). Khi luc tht phn ln cc chit xut tan trong nc ha tan vo nc lm cho nc tht c mi v thm ngon c hiu. Cc protein ca c s gim ha tan khi nhit gia 40-60oC v lc ny mch polypeptit b gin v keo t. Khi nu kh nng gi nc ca t c cng gim lm cho tht b sm mu. i vi c, thnh phn protein ch yu l albumin, globulin v nucleoprotein. T chc v lin kt thp v phn phi u, gn nh khng c elastin. Protein ca c d ng ha hp thu hn tht. nh hng ca lnh ng.

Lnh ng l phng php bo qun tht rt tt, tuy nhin cng lm xu i mt s tnh cht ca tht. cc bin i xy ra khi lm lnh ng ph thuc vo cc yu t tc lm lnh, nhit ti thiu t c v thi gian bo qun.

nhit lnh ng trhng thng (-30 n -20oC ) 90% nc ng li lm cho nng cc cht ha tan trong nc cha ng tng ln 10 ln. Trong vng c mt ca dung dch ny protein b bin tnh mnh m do lc ion tng ln v pH thay i ln.

Lnh ng lm thit hi cu trc t bo. Khi lm lnh chm th cc tinh th nc ln s to ra trong mi trng ngoi bo. p sut thm thu khi u ca n b hn mi trng ni bo nn nc s chuyn t mi trng ni bo ra mi trng ngoi bo. Tc th lc ion trong mi trng ni bo tng ln ng k, t bo b tiu nguyn sinh v cc protein b bin tnh.

Khi lm lnh nhanh s lm to ra nhiu tinh th nc trong tht v do s chuyn nc gia mi trng ni bo v ngoi bo l ti thiu. Lc ny s bin tnh protein l khng ln.

Hu qu chnh ca s bin tnh protein l kh nng gi nc gim v s chy dch s xut hin ngay sau khi lm tan . Dch chy ra cha cc vitamin, c mui khong, cc axitamin,. tn tht v dinh dng t, nhng tn tht v trng lng ln, tht tr nn kh v x. nh hng ca s kh nc

Kh nc bng phng php sy thng hoa cng km theo s gim kh nng gi nc sau khi ti hidrat ha v lm cng cu trc. S d c nhng bin i ny l do tng tc gia cc phn t actomiozin qua cu mui lm trung gian. nu c mt saccharose th hin tng ny s gim i.

Kt lun

Trong qu trnh bo qun v ch bin, cc protein ca tht b bin tnh lm gim mt phn gi tr dinh dng v thay i mt s tnh cht. tuy nhin c c nhng sn phm nh mong mun, i khi ta cng phi hi sinh mt phn gi tr dinh dng

Qu trnh bo qun ca c tng i kh hn so vi tht v- Hm lng nc tng i cao trong cc t chc ca c.

- S c mt ca cc mng nhy l mit trng tt cho cc vi khun pht trin. mng nhy xut hin do khi c ra khi nc thng tit ra cc cht nhy ng li trn vy. Cht nhy c cha nhiu protein gip vi khun pht trin tt hn.

- Tnh a dng ca ngun xm nhp. Ngoi vy c, vi khun cn c th xm nhp t nhiu ngun khc nh mang v rut.

2. H thng protein ca trng. Protein ca lng trng trng.

Thnh phn dinh dng

Ovalbumin : l protein giu nht ca lng trng trng.

Phn t ovalbumin c 4 nhm SH v 2 cu disunfua. Trong thi gian bo qun s cu disunfua s tng ln do hnh thnh lin kt S-ovalbumin c tnh bn nhit hn protein ban u. S-ovalbumin chim 5% khi trng mi , tng ln 40% khi bn th trng v 80% trong trng bo qun lnh 6 thng.

Ovalbumin c kh nng to gel tt, lm cho bt bn. Khi gia nhit kh nng to gel ca S-ovalbumin gim.ovalbumin d b bin tnh nn c tc dng n nh cc bt to ra khi nhit lnh. Conalbumin : l mt glucoprotein, to phc vi cc ion kim loi ha tr 2 v 3 nh Cu2+, Zn2+, Al3+ , Fe3+ . cc phc c mu khc nhau ty thuc vo kim loi, phc Cu2+ mu , phc Fe3+ mu nu. dng phc kim loi th bn nhit hn protein lc u.

Ovomuxoit : l mt glucoprotein c hot tnh antitripxin v c tnh rt chu nhit tr khi trong mi trng kim.

Ovumoxin :l mt glucoprotein. Do c cc gc axit xialic tch in m nn to ra lc y tnh in lm cho c cu trc th v c tnh cht nht ca lp lng trng. Ovumoxin cng lm bn bt nhit lnh. Avidin : gm ba thnh phn A, B ,C to phc vi biotin.

Protein ca lng trng trng c tnh khng khun trc tip hay gin tip( dng protein hay dng phc ) gp phn bo v phi cng nh bo qun trng.

Cc bin i khi bo qun. Cc protein ca lng trng nguyn kh tiu ha, ch sau khi nu mi tr nn d dng. Nguyn nhn l do hot tnh khng tripxin ca omuvoxoit v tnh chng chu vi cc enzym tiu ha nn mt s globulin khng b bin tnh.

S chuyn ovalbumin thnh S-ovalbumin, s phn ly phc ovomuxin-lizozim km theo s ph hy gel ovomuxin l nhng phn nh quan trng trong thi gian bo qun trng lm nh hng ti kh nng to gel, to bt v kh nng ha lng ca lng trng trng. Lng CO2 trong trng cng gim lm pH tng t 7,6 ln 9,7.

Trng mi ra bn trong coi nh tit trng nhng ngoi v c rt nhiu vi khun. Khi ra thng lm cho vi khun xm nhp vo d dng do mt lp biu b protein bo v cng nh do nc i vo ko theo vi khun. Do sau khi ra, trng phi c lau kh ngay.

C th lm gim cc l trn v trng bng cch nhng vo du khong, hoc gia nhit nhanh trong nc lm ng t lp protein di v.

Protein ca lng trng. Thnh phn.

Do 3 protein lin kt vi nhau to thnh mt phc. lipovielin v phosvitin l hai hp phn c s. Lipoprotein nh s kt dnh vo phc qua phosvitin lm cu ni trung gian.

Phosvitin c kh nng c ng cc ion st. Cc phc to ra tan trong nc v l ngun d tr st.

Protein ca trng giu axit amin cn thit. thnh phn cc axit amin rt n nh v hu nh khng ph thuc vo ging, thc n cng nh phng php nui ng vt. Cc bin i trong bo qun.

Khi lng trng ng v c bo qun nhit -6oC tht nht ca sn phm sau khi tan gi thng tng ln rt nhiu. kh nng to gel tng khi bo qun nhit -50oC. Nu thm cc cht h im ng bng th cng hiu qu ( sacaroza hoc mui nng 8-10%, glyxerin 5% ). Khi gia nhit ( nu nng ch bin ) th lng c li v tr nn kh, mt s protein ca lng trng to ra H2S. Nu nu trong thi gian ko di m khng lm lnh th H2S s phn ng vi Fe c mt trong lng to kt ta en. Ta c th thc hin phn ng ny thu c trng hon ton en v cht lng.

Trng nguyn khi sy kh th lm bin tnh mt phn protein v lm thay i mt s tnh cht v chc nng ca chng.

C th thm ng hoc mui bo qun. Lng trng trng c c c ng thng cha 40% sacaroza, 1% natri clorua v 40% nc c th bo qun nhit bnh thng trong nhiu thng. Lng mn c ng, cha 10% natri clorua v 10% sacaroza c hot nc l 0,85.

3. H thng protein ca sa. c im v gi tr dinh dng.

V phng din l hc, sa l mt h thng phc tp, l mt huyn ph cc ht keo trong pha phn tn l nc, bao gm cc mixen protein.

Sa l thc phm c gi tr dinh dng cao. Protein sa rt qu v thnh phn axitamin cn i v c ng ha cao. Thnh phn chnh ca protein sa bao gm : Casein, lactoalbumin, v lactoglobulin. Sa b, sa tru, sa d thuc loi sa Casein v lng Casein chim > 75% tng s protien. Sa m thuc loi albumin ( lng Casein di 75% )

Sa c kh nng to gel, to nh tt. cc sn phm t sa nh kem, pho mt, b, sa kem Thnh phn protein trong sa.

nh hng ca cc qu trnh x l cng ngh. Hiu qu ca gia nhit.

Khi thanh trng Pasteur cng nh khi c c sa di 100oC th -lactoglobulin b bin tnh. 80oC protein trong dung dch bt u to gel. S to gel do khi cu trc cu b gin mch, cc tiol t do xut hin lin kt vi nhau hoc vi cc cu disunfua. Khi s to ra nhng phc hp ga cc protein ha tan b bin tnh v cc hp phn cha S ca mixen.

Khi nhit trn 100oC phn ln cc protein ca lactoserum lin kt vi mixen casein v lm cho chng bn vi proteaza. Phc hp -lactoglobulin-casein K cng to thnh lm bn cc protein ca sa i vi s thanh trng 120-140oC sau ny cng nh i vi tc dng ng t ca cc enzym.

nhit 110-120oC, bn ca cc protien sa ph thuc rt mnh vo pH. Trong qu trnh gia nhit pH b gim do to ra cc axit hu c. Khi gia nhit nghim ngt s lm bin i cc casein. T nhit 110oC s xy ra cc phn ng thy phn gii phng ra photpho v nit phi protien. Photpho gim lm cho kh nng c nh canxi b gim.

Vic thanh trng cng ko theo phn ng Maillard lm cho mt phn gc lizin mt hot ng. Do s lm c ch mt giai on ph ca qu trnh ng t.

Nng cht kh ca sa tng s lm cho bn nhit gim ng k v lm tng nguy c to gel trong qu trnh bo qun.

Hiu qu x l lnh.

Khi bo qun sa nhit thp ( 2-6oC ) s gy ra hai kiu bin i : kh bn cc mixen v proteoliz hn ch.

Nhit thp lm thay i cn bng mui ( P v Ca ) gia cc mixen v cc pha ha tan, pH thay i. Kt qu l lm thay i thi gian ng t ca sa, lm thay i cng v lm hiu sut ca phomat. C th phc hi li bng cch thm mt t CaCl2, iu chnh v pH ban u, hoc x l nhit ( 60oC trong 30 pht ) ti hp th casein vo trong mixen. Nhit lnh cng lm tng s thoi bin casein thnh casein. Ty thuc vo thi gian v nht bo qun m lng casein ca sa thay i rt ln (2-10%).

Cc qu trnh proteoliz hn ch ny thng lm bin i thnh phn ca mixen v do lm thay i tnh cht l hc v cng ngh ca casein.

4. H thng protein ca mu. Thnh phn v s phn on mu. Trong mu c khong 17% protein nn ngi ta gi mu l tht lng.

So vi protein ca trng th protein ca mu hi thiu izolxin v methionin. iu dng ch y l st trong heme ca hemoglobin c gi tr dinh dng cao, v dng ny st d c rut hp th.

gn 200 protein c mt trong mu, hin nay ngi ta d tch v tinh chit c trn 70 loi. Tr albumin v mt vi loi protein c hot tinh enzym nh lisozin, a- amilaza, tt c protein cn li l glucoprotein.

Mt s protein c trong mu.

Serumalbumin ( albumin ca huyt tng ) : chim 60% tng lng protein trong huyt tng. N cu to bi mt chui polypeptit vi 182 axitxmin, c 17 cu disunfua v mt nhm SH t do. Vai tr ca n l c nh v chuyn ti cc phn t nh hu c ni sinh hoc ngoi sinh, hoc cc cht khong. Globulin : tch khi albumin d dng bng cch kt ta chn lc vi Natri Sunfat. Fibrinogen l tin thn ca fibrin, chc nng lm cho mu ng c.

Hemoglobin nh v trong cc huyt cu t, gm nhiu chui polypeptit lin kt vi mt nhn heme. Cc yu t nh hng. Trong qu trnh gia nhit mu ca Hemoglobin b bin i do hi tng oxy ha.

Ch c axit ascocbic mi lm chm c qu trnh oxy ha hemoglobin. Cacbon oxyt hoc nitrit cho nhng mu bn tuy hi khc ban u. Hemoglobin c lm bn mu bng nitro c th dng nhum mu cc sn phm tng t tht t protein thc vt.

C th lm t mu mu bng cch khuy trn vi sa tch kem 95oC, c mt CaCl2 trong 5 pht.

C th kh mu ca hemoglobin bng cch chit sc t heme ra khi globin bng cc phng php ha hc hoc bng enzym.

5. H thng protein ca ng cc.

Ng cc l ngun chnh cung cp nng lng cho khu phn n hng ngy ca nhn dn ta, ng thi cng l ngun protein thc vt.

Protein ca ng cc l protein khng hon ho, thng thiu cc axitamin khng thay th . Hm lng protein thp ch khong t 10-13% hp thu tng i thp ch khong 50-70%. Ch c protein ca cc loi u tng i hon ho. Trong ng cc ( tr yn mch ) prolamin v glutelin l hai nhm protein chim 75-95% tng lng protein ca ht.

Protein ca la m.

Thnh phn.

Ht la m thng cha trung bnh 13% protein, c loi cha n 25%. Hm lng protein c th do di truyn, iu kin canh tc v ph nhiu ca t.

Protein ca la m tng i y cc axit amin khng thay th. Hai protein chnh c trong la m l prolamin v glutelin. phn prolamin trong la m c tn l gliain, phn glutelin c tn l glutenin. Gliain v glutenin chim phn ch yu ca gluten bt m. Gliain c trng cho gin, cn glutenin c trng cho n hi ca bt nho t la m. Chnh nh tnh cht n hi ca protein ny m bt m mi lm bnh c. Cc gliadin v glutenin c hm lng glutamin rt ln (40 45 %) do ko theo c hm lng nit. Hm lng glutamin cao s hnh thnh nhiu lin kt hydro gia cc chui peptid vi nhau hoc vi cc phn t nc, do to cho gluten c tnh nht do cao. Hm lng axit amin a bo tng i cao cho thy tng tc a bo chng nhng tham gia vo cu trc bc 4 ca glutenin m cn lin kt vi mng li gluten trong bt nho. Gliain

Trong la m c 2 nhm prolamin chnh:

- Gliadin , , c phn t lng 30 000 - 45 000 dalton

- Gliadin c phn t lng khang 60 000 n 80 000 dalton Cc Gliadin , , cn c cc cu disunfua trong phn t lm cu trc bn v cht. cc gliain c hm lng glutamin v prolin rt cao 75%. Glutenin

Cc glutenin c tnh a hnh mnh m hn gliain v xu hng t lin kt vi nhau bng tng tc a bo, lin kt hydro v cu disulfua ca chng ln hn. Khi lng phn t c th ln n 20 triu dalton, nht l nhng protein cn khng ha tan trong acid acetic 0,1M. nhng protein ny hu nh u l nhng glutenin lin hp li bng cu disulfua.

Khi ph hy cc cu disulfua gia cc phn t ,ngi ta thu c 25 di n v glutenin.- Kiu A: khng ha tan c trong etanol, khi lng phn t thp (10000 - 70000 dalton ) v rt giu cc acid amin c tnh baz

- Kiu B: khng ha tan trong etanol nhng c khi lng phn t cao (60000 140000 dalton), giu glyxin, prolin v glutamine, ngho xiatein, t l xon trong phn t thp (10 15 %).- Kiu C: ha tan c torng etanol ,c khi lng phn t khang gia 35000 45 000 dalton Cc di n v lin kt vi nhau bng lin kt hidro, bng tng tc a bo v bng cu disunfua.Cc phc hp glutenin c phn t lng ln thng cha kiu B, C. Cn cc phc hp glutenin c khi lng phn t thp th c t l kiu C kh cao. trng thi ngm nc cc glutenin to ra mt mng mng rt chc, n hi v c tnh ht c kt cao chu c lc cng. Tnh cht ny do cng tng tc v s lng tng tc gia cc chui protein.

Bt m nho do v gi kh nn khi gia nhit s hnh thnh mt cu trc xp bnh m. Lng protein cn cng cao lc n ca bnh cng tng. ngc li, lng protein ha tan c trong axit axetic 0.1 M cng tng th lc n gim xung. Do vy la m cng khng lm bnh c v hm lng protein cn thp. tng cht lng bt nho c th thm mt t tc nhn oxy ha.

Glutenin c tnh a bo nn chng lin kt c vi lipit to nn nhng mng mng khng thm i vi kh CO2.

Cc bin i khi bo qun.

Trong qua trnh bo qun, cht lng gluten v bnh nng tng ln r rt. bo qun trong vng 2-4 tun u th gluten tr nn n hi, t nho hn, do hn v do cht lng bnh nng tt hn, th tch bnh ln hn, v bnh xp hn.

S tng cht lng gluten l do qu trnh thy phn cht bo nh tc dng ca enzym lipaza. Cc axit bo cha no to thanh c tc dng mnh m n gluten lm chng lin kt cht hn v tr nn do, n hi hn.

Mc d lm tng cht lng gluten nhng cng chnh mt s axit ny li c tc dng lm gy ng sn phm.

Protein ca u tng. Thnh phn. Hm lng protein trong u tng ni chung tng i cao t 40-45% protein tp trung ch yu c l mm. ta c th chia lm hai loi :

- Protein d tr b thy phn trong qu trnh ny mm lm cht dinh dng cho phi sinh trng.

- Cc protein cu trc hoc protein chc nng enzym hay km hm enzym th tp trung phn cn li ca t bo.

Cc globulin 7S v 11S chim trn 70% tng lng protein ca ht.

Mt trong nhng tnh cht quan trng ca protein u tng l kh nng to gel.

S to gel.

Khi dung dch protein u tng c nng m dc ( > 5% P/V ) c un nng pH gn trung tnh th s to gel. Axit ha dung dch protein u tng n pH = 5.5 hoc thm ion Ca2+ s lm ng t protein thnh nhng cc. cc gel ny thng cng hn cc gel to bng cch gia nhit. cc gel c ion canxi th li n hi hn.

lm u h th sa u ( c khong 4.5% protein ) trc tin phi gia nhit nhit 100oC trong 3 pht, sau cho thm Ca2+ vi nng khng qu 0.4M.

S to gel ca protein u tng cng c th thc hin bng kim ha ri trung ha.Casein s1(15-19g/l)

Casein s1(15-19g/l)

Casein (24-28g/l )

-Lactalbumin(1-1.5g/l)

-Lactoglubin(2-4g/l)

Protein ha tan(5-7g/l)

Nit phi protein(0.3-0.4g/l)5%.

Protein(30-35g/l) 95%

hp cht nit ca sa 100%

Hng cu

Fibrin

Globin

Heme

Hemoglobin

Huyt tng

Cc ng

Khng b ng

ng t

Mu nguyn + cht chng ng

Cht m

Hng cu

Huyt thanh

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