TRNG I HC CNG NGHIP THNH PH H CH MINH

VIN CNG NGH SINH HC THC PHM

cco0odd

TIU LUN

Mn: CNG NGH CH BIN THY SN

ti: CNG NGH SN XUT C BASA

PHI L NG LNH

GVBM: NGUYN HUNH .THUN

LP: HTP8A

SVTH:

TRN TH HNG N 12034751

TN N YN NHI 12019711

S CN TC 12010621

NGUYN THU TRANG 12031951

TP.HCM, thng 4 nm 2015

NHN XT CA GV

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MC LC

Phn 1: TNG QUAN V NGHNH THY SN CA NC TA ............................. 1

1.1.c im chung ............................................................................................................ 1

1.2.Tnh hnh ch bin thy sn vit nam .......................................................................... 1

1.2.1.Cc giai on pht trin .......................................................................................... 1

1.2.2. Th trng xut khu thy sn ca Vit Nam ........................................................ 2

1.2.3. Sn lng v xut khu thy sn thng 3/2015 .................................................... 4

1.3.c im sinh hc ca c ba sa ..................................................................................... 5

1.3.1 Phn loi c ba sa ................................................................................................... 5

1.3.2.Phn b .................................................................................................................. 5

1.3.3.Hnh thi, sinh l ................................................................................................... 6

1.3.4.c im dinh dng ............................................................................................ 6

1.3.5.c im sinh trng ............................................................................................ 7

1.3.6.Gi tr dinh dng .................................................................................................. 7

Phn 2: QUY TRNH V THUYT MINH QUY TRNH SN XUT C BASA

FILLET NG LNH IQF ................................................................................................ 9

2.1. Quy trnh ...................................................................................................................... 9

2.2. Thuyt minh quy trnh ............................................................................................... 10

2.2.1. Tip nhn ngyn liu .......................................................................................... 10

2.2.2. Ct tit ra 1 .................................................................................................... 10

2.2.3. Phi l ................................................................................................................... 11

2.2.4. Ra 2 ................................................................................................................... 12

2.2.5. Lng da ............................................................................................................... 13

2.2.6. Chnh hnh .......................................................................................................... 13

2.2.7. Soi k sinh trng ................................................................................................. 14

2.2.8. Ra 3 ................................................................................................................... 14

2.2.9. Quay thuc .......................................................................................................... 15

2.2.10. phn c, loi ...................................................................................................... 15

2.2.11. Cn 1 ................................................................................................................. 16

2.2.12. Ra 4 ................................................................................................................. 16

2.2.13. Ch ng .......................................................................................................... 17

2.2.14. Cp ng ............................................................................................................. 17

2.2.15. M bng ............................................................................................................ 18

2.2.16. Ti ng ............................................................................................................ 18

2.2.17. Cn 2 ................................................................................................................. 19

2.2.18. D kim loi ....................................................................................................... 19

2.2.19. Bao gi .............................................................................................................. 20

2.2.20. ng thng .......................................................................................................... 20

2.2.21. Bo qun ............................................................................................................. 21

Phn 3: K THUT LM LNH NG SN PHM ................................................. 22

3.1.Mc ch ngha ........................................................................................................ 22

3.1.1.nh ngha ........................................................................................................... 22

3.1.2.Mc ch lm lnh ng thy sn ........................................................................ 22

3.1.3.Cc yu t nh hng n thi gian lnh ng thy sn ..................................... 23

s3.2.Nhng bin i ca thy sn sn trong qu trnh lm ng lnh. ............................. 26

3.2.1.Bin i vi sinh vt .............................................................................................. 26

3.2.2.Bin i ha hc .................................................................................................. 26

3.2.2.1.Bin i cht m ......................................................................................... 26

3.2.2.2.Bin i cht bo .......................................................................................... 26

3.2.2.3.Bin i gluxit .............................................................................................. 26

3.2.2.4.Bin i vitamin ........................................................................................... 27

3.2.2.5.Bin i cht khong .................................................................................... 27

3.2.3.Bin i l hc ..................................................................................................... 27

3.2.3.1.Tng th tch ................................................................................................. 27

3.2.3.2.Thay i mu sc .......................................................................................... 27

3.2.3.3.Gim trng lng .......................................................................................... 27

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Phn 1: TNG QUAN V NGHNH THY SN CA NC TA

1.1.c im chung Vi ng b bin di hn 3.200 km, vng c quyn kinh t trn bin rng hn 1

triu km2, vng mt nc ni a ln rng hn 1,4 triu ha , v tr a l v iu kin t

nhin thun li gip Vit Nam c nhiu th mnh ni tri pht trin ngnh cng

nghip thy sn. T lu Vit Nam tr thnh quc gia sn xut v xut khu thy sn

hng u khu vc, cng vi Indonesia v Thi Lan. Xut khu thy sn tr thnh mt

trong nhng lnh vc quan trng ca nn kinh t.

1.2.Tnh hnh ch bin thy sn vit nam

1.2.1.Cc giai on pht trin

Ni v thy sn khng th khng nhc n vai tr, v tr ca ngnh ch bin thy

sn. sNhng bc thng trm ca ngnh ny lun gn lin vi nhp sng chung ca nn

kinh t t nc, nht l cng cuc i mi ton din t nc. Bi vy, qu trnh

pht trin ca ngnh ch bin thy sn c th c hnh dung qua cc giai on sau:

1.2.1.1.Giai on 1975-1980

Nm trong tnh trng tr tr chung ca kinh t t nc, ngnh thy sn cng lm vo tnh trng sa st ko di.

Cc c s ch bin c c ch yu bng ngun vin tr khng hon li ca quc t. Nm 1980 c nc mi ch c 40 c s ch bin ng lnh vi tng cng sut cp ng l 172 tn/ngy. Trong khi nhiu nh my xy dng xong nhng khng pht huy c cng sut, nguyn liu khai thc ch c huy ng cho ch bin t 20 - 30%.

1.2.1.2.Giai on 1981-1994

Trong 13 nm lin tc, ngnh thy sn lun hon thnh vt mc ton din cc ch tiu k hoch Nh nc giao vi tc tng trng bnh qun 5 - 7%/nm v sn lng khai thc, 12 - 13% v gi tr kim ngch xut khu. Ni bt nht trong giai on ny l lnh vc ch bin pht trin rng khp vi tc tng bnh qun 9 nh my mi nm.

Thm vo cn c h thng cc nh my sn xut nc vi tng cng sut 2.000 tn/ngy... to ra bc pht trin nhy vt v cht trong qu trnh gi gn ti ca nguyn liu, gim tiu hao, tht thot sau thu hoch, gp phn nng cao gi tr

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kinh t ca sn phm. Kt qu l t l sn phm ch bin ng lnh so vi tng nguyn liu tng nhanh v t 51%/nm vo nm 1994 so vi 11,4%/nm vo nm 1980.

1.2.1.3. Giai on1994 2000

Ngnh ch bin thy sn cng nhn c s ch trng c bit ca cc cp, cc ngnh v cc a phng. Nhiu chng trnh, d n to bo nh nh bt xa b c hnh thnh. Xut khu tng mnh.

1.2.1.4.Giai on 2001 n 2014

Ch bin xut khu thy sn l ng lc cho tng trng v chuyn i c cu

trong khai thc v nui trng thy sn. C nc c tng s hn 470 c s doanh

nghip ch bin thy sn. Trong , 248 c s - doanh nghip (chim gn 53%) t

tiu chun ca th trng EU - mt th trng kh tnh vo bc nht th gii; trn 300

c s - doanh nghip c Hn Quc cng nhn tiu chun cht lng

1.2.1.5.Giai on t nm 2014 n nay

Ngnh thy sn tip tc c bc t ph trn cc lnh vc t khai thc, nui trng n ch bin, xut khu, trong ln u tin gi tr xut khu thy sn t gn 8 t USD.

Nm 2014, mc d phi i mt vi nhiu kh khn nhng ngnh thy sn vn t tng sn lng 6,3 triu tn, tng 4,4% so vi cng k nm ngoi. Gi tr xut khu t 7,920 t USD, tng 18% so vi nm ngoi, vt 11,6% so vi k hoch.

Nm 2015, ton ngnh thy sn phn u tng sn lng t 6,6 triu tn, tng 5,5% so vi nm 2014, gi tr xut khu t 8,5 t USD.

1.2.2. Th trng xut khu thy sn ca Vit Nam C cu th trng xut khu thu sn thay i r nt k t nm 2000 n nay. M

v Nht Bn tr thnh th trng tiu th thu sn hng u ca Vit Nam, tip l th

trng EU. Cc th trng chu nh i Loan, Hn Quc c v tr kh n nh.

+ M: l mt trong nhng th trng nhp khu thu sn hng u ca Vit Nam. C tra,

basa phi l ng lnh l mt hng c o ca Vit Nam ti th trng M

+ Nht Bn: l th trng em li hiu qu cao cho xut khu thy sn ca Vit Nam. S

thiu ng b trong h thng bo m an ton cht lng sn phm thu sn ca Vit Nam

ang l vn rt ln trong vic duy tr ch ng trn th trng Nht Bn

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+ EU: l th trng c nhu cu ln v n nh v hng thu sn, nhng li l th trng

c coi l c yu cu cao nht i vi sn phm nhp khu, vi cc quy nh kht khe

v cht lng v an ton v sinh. Vic xut khu sn phm sang th trng EU s gp

phn nng cao uy tn ca hng thu sn Vit Nam trn th trng th gii

+ Trung Quc v Hng Kng: l nhng th trng nhp khu thu sn trung bnh trn th

gii. Trong tng lai, Trung Quc s l th trng tiu th thu sn hng u ca khu

vc chu , vi c im tiu th ca th trng ny l va tiu th cho dn c bn a,

va l th trng ti ch v ti xut.

+ Mt s th trng khc:

Cc th trng khc thuc chu c quan tm ngy mt nhiu hn, nht l Hn

Quc v i Loan. Cc th trng ny ch yu nhp khu c bin, mc, bch tuc.

xtrylia: xut khu sang th trng ny vn c s tng trng tuy nhp khng u

Th trng ng u :mc d kim ngch xut khu cn cha cao nhng y cng l 1 th

trng xut khu y tim nng. s

Top 10 th trng xut khu c tra ln nht trong thng 2/2015 theo lng v t

trng

Th trng Lng (nghn tn) T trng (%) M 5.415 14,68 Mexico 3.696 10,02 Colombia 2.323 6,30 Trung quc 1.925 5,22 Saudi Arabia 1.767 4,79 Philippines 1.343 3,64 H lan 1.277 3,46 Ty Ban Nha 1.254 3,40 Thi Lan 1.168 3,16 Hng Kong 998 2,71 Tng 36.896 100,00

Ngun : AgroMonitor Tng hp s liu ts Tng cc Hi quan

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1.2.3. Sn lng v xut khu thy sn thng 3/2015 Tng sn lng thu sn thng 3 c t 1.260 ngn tn, tng 2,9% so vi nm

2014, trong sn lng khai thc c t 750 ngn tn, tng 3,2%; sn lng nui

trng c t 510 ngn tn, tng 2,4% so vi nm 2014.

Gi tr xut khu thy sn c t 417 triu USD, a gi tr xut khu 3 thng u

nm 2015 t 1,27 triu USD, gim 20,6% so vi cng k nm 2014.

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Hoa K vn duy tr c v tr l th trng nhp khu hng u ca thy sn Vit

Nam, chim 18,62% tng gi tr xut khu. Trong 2 thng u nm 2015, xut khu thy

sn sang th trng ny t 159,05 triu USD, gim 40,22% so vi cng k nm 2014.

Xut khu sang Nht Bn cng gim ng k vi mc gim l 11,73%. Xut khu tng

trng cc th trng nh Trung Quc (tng 47,3%), Mhic (tng 42,81%), Thi Lan

(tng 8,73%), Hn Quc tng (1,91%).

1.3.c im sinh hc ca c ba sa

1.3.1 Phn loi c ba sa Theo h thng phn loi Tyson Roberts, c ba sa thuc h Pangasiidae, ging

Pangasius, loi P. Bocourti. Trc y c ba sa c nh danh l Pangasius pangasius

(hamilton).

1.3.2.Phn b C ba sa phn b lu vc sng M kng, c mt c 4 nc Lo, Vit Nam,

Campuchia v Thi Lan. Thi Lan cn gp c ba sa sng Chaophrava. nc ta

nhng nm trc y khi cha c c sinh sn nhn to, c bt v c ging ba sa c vt

trn sng Tin v sng Hu. C trng thnh ch thy trong ao nui, rt t gp trong t

nhin a phn Vit Nam, do c c tnh di c ngc dng sng M kng sinh sng v

tm ni sinh sn t nhin.

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1.3.3.Hnh thi, sinh l C ba sa (cn gi l c bng) l c da trn, c thn di, chiu di chun bng 2,5 ln

chiu cao thn. u c ba sa ngn, hi trn, dp bng, trn rng. Ming hp, chiu rng ca ming t hn 10% chiu di chun, ming nm hi lch di mm. Di rng hm trn to v rng v c th nhn thy khi ming khp. C 2 i ru, ru hm trn bng chiu di u, ru mp di ti hoc qu gc vy ngc. Mt to, bng to, l m rt ln, phn sau thn dp bn, lng v u mu xm xanh, bng trng bc. Chiu cao ca cung ui hn 7% chiu di chun.

C basa khng c c quan h hp ph, ngng oxy cao hn c tra, nn chu ng km mi trng nc c hm lng oxy ha tan thp.C ba sa sng ch yu nc ngt, chi c nc l nh, nng mui 12%, chu ng c ni nc phn c pH >5,5. Ngng nhit t 18 40oC, ngng oxy ti thiu l 1,1mg/lt. Nhn chung s chu ng ca c ba sa vi mi trng khc nghit khng bng c tra, do c c nui thng phm ch yu trong b trn sng nc chy.

1.3.4.c im dinh dng C ba sa c tnh n tp thin v ng vt. H tiu ha ca c thc s hon chnh 3

ngy sau khi bt u n thc n bn ngoi. C cng ho n nhng t tranh mi hn so vi c tra. Sau khi ht non hong , c n ng vt ph du l chnh.

Trong iu kin nui nhn to thc n thch hp giai an u l u trng Artemia, Moina, t c t l sng ti 91-93%, trong khi dng thc n nhn to th t l sng ch t 67% v tc tng trng cng km hn. T ngy tui th 7 c th chuyn sang n thc n nhn to. Nhu cu protein ca c ba sa khong 30-40% khu phn, h s tiu ha protein khong 80-87% v h s tiu ha cht bo kh cao 90-98%.

Giai on ln c cng c kh nng thch ng nhanh vi cc loi thc n c ngun gc ng vt, thc vt v d kim nh hn hp tm, cm, rau, c vn v ph phm nng nghip, do thun li cho ngi nui khi cung cp thc n cho c trong b.

Khi phn tch thc n trong rut c nh bt ngoi t nhin, cho thy thnh phn thc n kh a dng, c ba sa thin v ng vt v mn b hu c.

C ba sa thnh thc tui 3+ n 4. Trong t nhin vo ma sinh sn (thng 3-4 hng nm) c ba sa ngc dng tm cc bi thch hp v trng. C ba sa khng c c quan sinh dc ph nn cng kh phn bit c c ci khi nhn hnh dng ngoi. Khi c giai an trng thnh c th phn bit bng cch vut tinh dch c c v thm trng c ci. H s thnh thc ca c (nui v trong ao v b) t 2,72 - 6,2%, sc sinh sn tuyt i t ti 67.000 trng (c 7 kg), ng knh trng t 1,6-1,8 mm. C trng dnh vo gi th thng l r ca loi cy sng ven sng Gimenila asiatica, sau 24 gi th trng n thnh c bt v tri v h ngun.

Trong sinh sn nhn to, ta c th nui thnh thc sm v cho sm hn trong t nhin (t thng 3 dng lch hng nm). Ma v sinh sn c ba sa ngoi t nhin c tnh chu k r rt.

Vo thng 8, sau khi kt thc ma sinh sn, tip theo l qu trnh thoi ho v c th s hp thu nhng sn phm sinh dc cn st li, bung trng ch cn l cc nang rng v vo nhng thng cui nm tr v giai an II. Cc thng tip theo sau l qu trnh hnh thnh cc ht trng mi, bung trng tng dn kch thc v t ln nht vo thng 4-5(

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nm sau). Vo thng 6-7, ng knh trng t 1,5-1,7mm v c bc vo thi k sinh sn khi ng knh trng t 1,8-2mm.

T thng 7 tr i l thi k c trng. Trong nui v sinh sn nhn to, ma v thnh thc v ca c ba sa thng sm hn trong t nhin t 2-3 thng, c thnh thc v bc vo ma v sinh sn nhn to t thng 3 v ko di n thng 7, tp trung vo thng 4 - 5.

1.3.5.c im sinh trng c ba sa, thi k c ging cng ln kh nhanh, sau 60 ngy c t chiu di 8-

10,5 cm, sau 7-8 thng t th trng 400-550 gam, sau 1 nm t 700-1.300 gam. Nghin cu v tng trng c ba sa cho thy trong 2 nm u tin c tng trng nhanh v chiu di thn, cng v sau tc ny gim dn. Khi t n mt kch thc nht nh th chiu di thn hu nh ngng tng. Ngc li trong 2 nm u tc tng trng v th trng chm nhng tng dn v sau. Nui trong b sau 2 nm c th t ti 2.500 gam. Trong t nhin gp c c c chiu di thn 0,5m.

1.3.6.Gi tr dinh dng

Thnh phn dinh dng trn 100g sn phm n c

Calo Calo t cht bo

Tng lng cht bo

Cht bo bo ha

Cholesterol Natri Protien

170 cal 60 cal 7g 2g 22mg 70,6mg 28g

Cng nh cc loi c khc, tht c basa l ngun protein ng vt cht lng cao, cung cp nhiu protein, cc cht khong quan trng v c cha nhiu loi vitamin cn thit rt tt cho sc khe.

Tht c c hm lng protein t 23-28%, tng i cao hn so vi cc loi c nc ngt khc (16-17%). Cc protein trong c nhn chung d ng ha, d hp thu hn tht v cung cp y cc acid amin cn thit cho s pht trin ca c th con ngi.

Ngoi ra, ngi ta cn nhn thy rng tng lng cht bo c trong tht c thp hn so vi tht v phn ln chng l cc cht bo c li, c bit l hai cht dinh dng quan trng DHA v EPA. ng lu , nhng nghin cu gn y cho thy, m c basa cha mt lng DHA (Docosa Hexaenoic Acid) v EPA (eicosapentaenoic acid) (4.74% DHA v 0.31% EPA) m trc y, loi axit bo quan trng ny c xc nh l ch c trong m c hi, c ng, c sc, mt s loi c vng bin su. Nhiu cng trnh nghin cu khoa hc cng chng minh v nhng li ch ca acid bo khng bo ha trong c vai tr lm gim nguy c bnh tim mch. Nhng acid ny gup h mc cholesterol

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ton phn v cholesterol LDL (cholesterol xu) trong mu phng x va ng mnh, nhi mu c tim. C basa cn c trng bi hm lng cholesterol rt thp (21- 39 mg/100g). y l c tnh quan trng c khuyn co trong cc ch dinh dng nm lm gim lng cholesterol tiu th hng ngy trong ba n.

Cho n nay, c basa thc s chinh phc ngi tiu dng trn th gii nh vo gi tr dinh dng cao, v ngon v vai tr quan trng ca cc thnh phn c trong tht c.

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Phn 2: QUY TRNH V THUYT MINH QUY TRNH SN XUT C BASA FILLET NG LNH IQF

2.1. Quy trnh

Nguyn liu

Ct tit ra 1

Phi l

Ra 2

Lng da

Chnh hnh

Soi k sinh trng

Cp ng

Ti ng

Ti ng

Cn 1

Ra 4

Ch ng

M bng

Ra 3

Quay thuc

Phn c, loi Cn 2

Bao gi

ng thng

Tip nhn nguyn

liu

Bo qun

Thnh phm

D kim loi

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2.2. Thuyt minh quy trnh

2.2.1. Tip nhn ngyn liu -Mc ch:

+ Cn v kim tra khi lng nguyn liu u vo.

+ Xc nh trng lng, mc ti n, mu sc, gi tr cm quan ca c theo ng yu

cu m x nghip t ra.

- Thao tc: C sng c vn chuyn t khu vc khai thc n Cng ty bng ghe c

cho c cn sng. T bn c c cho vo thng nha chuyn dng ri chuyn nhanh n

khu tip nhn bng xe ti nh. Ti khu tip nhn QC kim tra cht lng cm quan (c

cn sng, khng c du hiu b bnh).

C nguyn con cn sng, cht lng ti tt. C khng bnh, khng khuyt tt. Trng

lng 500g/ con.

-Yu cu: C tip nhn phi c giy xc nhn:

+ Khng s dng khng sinh cm (CAP, AOZ, MG, LMG) hoc khng sinh c s dng

nhng phi ngng 4 tun trc khi thu hoch.

+ m bo l nguyn liu c nui trong vng kim sot t yu cu v d lng thuc

tr su v kim loi nng.

+ Mi l nguyn liu phi c m s ring. V sinh nh xng, cu cng, bng ti tc v

sau khi tip nhn nguyn liu.

+ Thao tc nhanh nhn, trnh c ln khi mt nc qu lu gy cht trc khi ch bin.

2.2.2. Ct tit ra 1 - Mc ch:

+ Cng on ct tit nhm lm cho mu chy ra, trnh ng mu trong tht lm gim cht

lng cm quan, ng thi lm c cht nhanh.

+ Ra nhm loi b bt tp cht, VSV v mt phn nht c bm trn than c to iu

kin cho cng on sau c sch s v thun li.

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-Thao tc:

+ C sau khi c tip nhn s c ln bn, sau dng dao ct su vo hu c cho

mu chy ra v chuyn c vo bn inox 500 lt thng qua mng np nguyn liu, cng

nhn x vi nc t vi nc vo bn, mi bn khng qu 1500 kg, sau dng dm

nha khuy o nh, u trnh lm try xc c.

-Yu cu:

+ Thao tc phi nhanh gn, chnh xc.

+ Dng c phi c v sinh sch s trc khi s dng.

+ Cng nhn phi tang b y dng c bo h lao ng v v sinh c nhn sch s.

+ Nc ra phi sch.

+ Thay nc sau mi ln ra.

2.2.3. Phi l - Mc ch: Tch phn tht ra khi xng c, loi b xng, vy, u. To gi tr cm

quan p cho ming c v theo yu cu cu khch hng.

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- Thao tc: S dng dao chuyn dng phi l c : Tch tht 2 bn thn c, b u, b

ni tng, di vi nc chy lin tc, thao tc phi ng k thut v trnh v ni tng,

khng st tht trong xng.

- Yu cu:

+ Ming c sau khi phi l khng b b ni tng, rch, vn, st xng, b mt phi nhn,

phng, p.

+ Dng c phi sch s.

2.2.4. Ra 2 - Mc ch: Loi b mu trn b mt ming ct v cht bn ln t ni tng trong qu trnh

phi l. Loi b bt mt phn VSV trn ming phi l, lm trng c tht c v tang gi tr

cm quan cho ming tht.

- Thao tc: Ming phi l c ra qua 2 bn nc sch. Trong qu trnh ra ming phi l phi o trn mnh loi b mu, nht v tp cht. - Yu cu: + Ra bng nc sch, nhit thng. + Ra phi sch mu. + Nc ra ch s dng mt ln. Mi ln ra khng qu 50 kg.

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2.2.5. Lng da - Mc ch: + Lm tng gi tr cm quan cho ming tht. + To iu kin cho vic nh hnh d dng hn + p ng theo yuc cu ca khch hng. -Thao tc: Dng dao hoc my lng da lng b da. t ming phi l ln bn my lng da, b mt da tip xa vi bn my, t t y nh phn da n vo li dao t ui n ht ming phi l. Sau khi lng xong th phn tht i vo phn r cha nguyn liu v em cn tnh nng sut, phn da tch i xung khay ph liu t pha di. - Yu cu: + Thao tc nh nhng ng k thut ming phi l sau khi lng da khng c phm vo tht ming c, khng lm rch tht ming c. + Khng st da trn ming phi l. + Khng phm tht hoc rch tht. + Cc dng c chuyn dng, bn my phi sch s.

2.2.6. Chnh hnh - Mc ch: + Lm theo yu cu ca khch hng, + Lm tng gi tr cam quan v g tr dinh dng cho ming c. + Nhm loi b tht , m trn ming phi l. -Thao tc: t ming c ln tht v lng ht phn da cn st li khu lng da. Sau lt mt trong ca ming c hng ln trn, dng dao lng b ht phn m bng, m lung, m d v ly ht xng d cn st li.

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- Yu cu: + Ming phi l sau khi chnh hnh phi sch phn tht , m, khng rch tht, khng st xng, b mt ming fillet phi lng. + Khng cn tht , m, xng. + Nhit 1500C.

2.2.7. Soi k sinh trng - Mc ch: Kim tra v pht hin k sinh trng tn ti trong ming c nm loi b chng m bo an ton thc phm. - Thao tc: + Kim tra k sinh trng trn tng ming phi l bng mt trn bn soi. + t ming c ln bn soi kim tra s hin din ca k sinh trng, di nh sang ca n, nh sang c th xuyn qua ming c gip ta nhn thy s hin din ca k sinh trng hoc mu bm tn ti trong ming c. Nu pht hin c c k sinh trng th phi tch ring ming c loi sang bn ph phm. - Yu cu: + Ming phi l sau khi kim tra k sinh trng phi m bo khng c k sinh trng. Nhng ming fillet c k sinh trng phi c loi b. QC kim tra li vi tn sut 30 pht/ ln. + nh sang n c cng 540- lux. + Phi soi c 2 mt ca c v thao tc pho nhanh chng, chnh xc.

2.2.8. Ra 3 - Mc ch: + Loi b vn c v VSV bm trn b mt ming c. + Lm sch ming phi l trc khi x l cng tip theo. -Thao tc: Sn phm c ra qua 2 bn nc sch c nhit T0 = 80C. Khi ra dng tay o nh ming phi l. - Yu cu: + Ra khng qu 200kg thay nc mt ln. + Nhit nc ra 800C + Qu trnh thay nc hp l.

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2.2.9. Quay thuc - Mc ch: + Tng gi tr cm quan cho ming phi l, mu sc ming c ti sng, bng p hn. + Tng tng lng ming tht, gim nh mc tiu hao nguyn liu, tng ga thnh sn phm. + To iu kin thun li cho cng on phn c, bt mu, phn loi c. - Thao tc: Sau khi ra cn c cho vo my quay, s lng c 100 400 kg/ m tu theo my quay ln hay nh. Sau cho dung dch thuc ( vy, mui + nc lnh nhit 3 7 0C) vo theo t l c: dch thuc l 3 : 1. - Yu cu: + Nhit dch thuc 3- 70C + Thi gian quay t nht l 8 pht + Nng thuc v mui tu theo loi ho cht ti thi im ang s dng + Nhit c sau khi quay 150C + T l tang trng t 8 -12 %. + Cc ha cht c s dng ng theo tiu chun ca b thy sn.

2.2.10. phn c, loi - Mc ch: + To s ng u v kch c v mu sc ca ming tht. + To iu kin cho cng on sau c thun li. - Thao tc: + Phn c ming c theo gram / ming, Oz/ ming hoc theo yu cu khch hng. Cho php sai s 2%. + C c phn thnh cc size nh : 60 -120; 120 -170; 170 - 220; 220 - Up (gram/ ming) hoc 3 5, 5 7, 7 9, 4 6, 6 8, 8 10, 10 12 (Oz/ ming), hoc theo yu cu ca khch hng. - Yu cu:

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+ Phi thng xuyn hiu chnh cn m bo chnh xc ca sn phm. + Thao tc nhanh gn trnh ming tht nm lu trn bn. + Phn c, loi theo tiu chun ca ngnh v yu cu ca khch hng.

2.2.11. Cn 1 - Mc ch: + Cn p ng yu cu ca khch hng, xc nh trng lng ng thi l c s xc nh nng sut ca cng nhn. + Phn sn phm thnh tng phn, to iu kin thun li cho cng on sau, gip tiu th sn phm d dng hn. - Thao tc: + C c cn theo tng c, loi trng lng theo yu cu khch hng. + Thng thng cn theo khi lng 3kg, 4.5kg. + Cn xong ghi th size, khi lng cn, ngy sn xut. - Yu cu: + Cn phi c hiuc hnh thng xuyn m bo chnh xc. + m bo trng lng tnh trn mi n v sn phm.

2.2.12. Ra 4 - Mc ch: Ra tang gi tr cm quan cho ming tht, loiaj b vn c v VSV bm trn b mt ming tht.

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- Thao tc: Sn phm c ra qua 1 bn nc sch c nhit 6 - 80C. Thi gian ra 15-20 giy. Khi ra dng tay o nh ming phi l. - Yu cu: + Ra khng qu 100kg thay nc mt ln. + Ra bng nc sch nhit nc ra phi kim tra thng xuyn.

2.2.13. Ch ng - Mc ch: + Ngn cn s pht trin ca VSV, hn ch s gim khi lng ca sn phm. + H thp nhit sn phm, rt ngn thi gian cp ng. + n nh cht lng sn phm, hn ch s pht trin ca VSV. - Thao tc: : bn thnh phm sau khi ra xong c cho vo ti PE (10 kg/ PE) buc kn ming v c ch ng trong cc bn cch nhit bng cch mui , nhit ch ng duy tr t 0 - 40C, thi gian ch ng khng qu 4 gi. - Yu cu: + Thi gian ch ng khng qu 4h. + Nhit kjo ch ng 1 40C. + Kho ch ng phi c v sinh sch s v kim tra nhit thng xuyn.

2.2.14. Cp ng - Mc ch: + nhit thp (-180C), nc trong sn phm gn nh kt tinh hon ton, enzyme b v hotaj, VSV hu nuhw khng th pht trin, ko di thi gian bo qun ca sn phm. +To hnh dng c nh cho sn phm v to iu kin thun li cho bao gi, bo qun sn phm. - Thao tc: Trc khi cp ng phi chy khi ng t ng n khi nhit t khong - 35 n- 40oC, khi mi a hng vo cp ng; thi gian cp ng bng chuyn khng qu 1 gi. Nhit trung tm sn phm t - 180C. - Yu cu: + Nhit cp ng: -330C

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+ Nhit tm sn phm: -180C + Thi gian cp ng: 20 30 pht ty theo c c.

2.2.15. M bng - Mc ch: + Ba v sn phm, tng gi tr cm quan v hn ch mt nc. + Gim tn hao nhit trong qu trnh bo qun, lm tng trng lng ca ming c. + Gim thiu va chm trong qu trnh vn chuyn, bo qun. + Chng qu trnh thng hoa nc trc khi bo qun. - Thao tc: C sau khi tch ra khi bng chuyn ri xung bng chuyn li. Pha trn bng truyn li l h thng vi phun dng m bng ngay khi sn phm ri khi bng chuyn. Vi h thng vi phun ny th sn phm c m bng ng u v hp v sinh hn. - Yu cu: + Nc m bng phi lnh, sch. + Nhit nc m bng t 0 n 30C.

2.2.16. Ti ng - Mc ch: H nhit sn phm nhm bo qun tt hn - Thao tc: Sn phm sau khi m bng c a vo bung ti ng m bo nhit sn phm t -180C.

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- Yu cu: + Ch s dng nhng dng c v sinh sch s. + Cng nhn phi lm v sinh sch s v y dng c bo h lao ng trc khi tip xc vi sn phm.

2.2.17. Cn 2 - Cn theo tng c, loi ring bit. - Tu theo yu cu tng n hng m c th cn trng lng khc nhau

2.2.18. D kim loi - Mc ch: + Loi b cc ming kim loi trong sn phm. + m bo an ton, v sinh thc phm. -Thao tc:Sn phm sua khi cn t yu cu c thc hin cho vo PE/PA sau chuyn qua cng on d kim loi pht hin v loi b mnh kim loi hin din trong sn phm. - Yu cu: + Sauk hi a qua my d kim loi khng cn hin din mnh kim loi no trong sn phm. + Tn sut kim tra my d kim loi vo u ca, cui ca v mi 1 gi/ ln.

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2.2.19. Bao gi - Mc ch: + Thun tin cho qu trnh ng thng. + Tng gi t cm quan cho sn phm, bo v sn phm khi cc iu kin ca mi trng. -Thao tc: + Bao gi theo tng c, loi ring bit. + Tu tng n hng ca khch hng m c th c quy cch ng gi khc nhau. + ai np 2 ngang 2 dc. K m hiu bn ngoi thng ph hp vi ni dung bn trong sn phm. - Yu cu: + Thng tin trn bao b phi theo quy nh hin hnh ca Nh nc Vit Nam hoc theo quy nh khch hng. + Bao gi ng loi, ng c, ng quy cch quy nh ring ca mi khch hng. + Thao tc nhanh, nh nhng, trng lm hng c. + Cc mi hn phi kn, bao b p, hp dn, d xp, d vn chuyn.

2.2.20. ng thng - Mc ch: + Bo v v thng tin sn phm bn trong. + To iu kin thun li cho vic bo qun, vn chuyn, phn phi v lu kho. + To v m quan, m bo cht lng theo yu cu khch hng. -Thao tc: Xp cc gi cng c, cng loi qua my d ki loi vo thng carto. C 10 ti ng thanhg mt thng, dng bng keo dn kn ming thng. t thng ln my ning, ning 4 dy quanh thng (gm 2 dy dc v 2 dy ngang). Cc dy ning khng c qu cht hay qu lng s nh hng n bao b v sn phm bn trong. ng thng c 10 kin hng th phi em bo qun trong kho lnh. - Yu cu:

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+ Cng nhn phi thc hin v sinh c nhn, mang y dng c bo h lao ng. + Sn phm su khi ng thng phi a vo kho bo qun ngay. + Thit b nh xng v thng carton phi sch s.

2.2.21. Bo qun - Mc ch: + Duy tr nhit sn phm mc thp. + Enzym b v hot, VSV b hn ch, ko di thi gian bo qun. + Trnh c s ph hoi ca cn trng, ngn cn s ly nhim VSV t bn ngoi. - Thao tc: Sau khi bao gi, sn phm cui cng s c chuyn n kho lnh v sp xp theo th t, bo qun nhit -200C 20C. - Yu cu: + Hng xp trong kho phi tit kim din tch. + Hng c cht theo tng loi ring. + Hng nhp trong kho phi ghi y cc k hiu thng tin v sn phm theo yu cu.

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Phn 3: K THUT LM LNH NG SN PHM

3.1.Mc ch ngha

3.1.1.nh ngha Lm lnh ng hay p ng (freezing) thy sn, l qu trnh lm lnh thy sn do

s ht nhit ca cht lm lnh ( bng mi) a nhit ban u ca c th thy sn

xung di im ng ng bng v ti -8-100C v c th xung thp hn na: -180,-

300 hay -400.

Nh vy phng php lm lnh ng, nc trong thy sn ng ng tng phn

ty theo mc h nhit. im eutecti (eutecti point) l nhit ti thiu ton b nc

trong t bo thy sn ng c, nhit ny l -550-650C v cn gi l im ng bng

tuyt i (absolutefreezing point) . Trong cng nghip ch bin lnh thy sn, ngi ta

khng dng n nhit ny v chi ph qu cao, hn na v phng din k thut, sn

phm thy sn im eutecti s khng t gi tr thm m v bn m ch cn n -

400C l m bo cht lng sn phm.

3.1.2.Mc ch lm lnh ng thy sn Lm lnh ng thy sn l h thp nhit , lm chm s h hng ca thy sn, sao

cho n khi r ng, ta khng th phn bit c thy sn ng lnh v thy sn ti

sng.

Bo qun thy sn bng p ng c mt s ng dng.Nu ni nh bt xa cng c v

vic vn chuyn c ko di nhiu ngy, nn p dng k thut lnh ng trn tu m

bo cht lng m c. Nu t cng v n ch cch khong qu xa, cng nn s dng

lm lnh ng m bo phm cht thy sn qua giai on tn tr, vn chuyn v phn

phi.

V sn lng nh bt khng ng u, c nhng lc thiu ht nn phi lm lnh

ng v tr ng sn phm lc r ma lp thi iu ha v phn phi mi lc, mi ni

cc loi thy sn cht lng cao v gi c n nh. Lm lnh ng v ch bin thy sn

vi mc lng va phi s tt hn l phi lm vi khi lng ln, khng c k hoch,

chng trnh, do s khng s dng tt ngun li ny.

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Nu xut khu thy sn thng c bo qun ng lnh v tr ng. Xut khu

thy sn ng lnh rt quan trng i vi cc quc gia ang pht trin, v nhng loi thy

sn c gi tr kinh t cao nh tm ng lnh l ngun ngoi t ng k, nn dnh xut

khu hn l tiu dng ni a. R rng l lm lnh ng c u im nhiu mt. V ch

n by gi nhu cu lm lnh ng mi tr nn bc bch cc quc gia ang pht trin

do vic m rng ngnh thy sn. phng php lm lnh ng v tr ng cho php loi

thc phm protein c gi tr cao ny c phn phi n mi th trng trn th gii.

3.1.3.Cc yu t nh hng n thi gian lnh ng thy sn Gm c:

Loi my ng

Nhit vn hnh my ng

H thng lnh v iu kin vn hnh

Tc gi ca my ng thi khng kh

Nhit sn phm

B dy sn phm

Hnh dng sn phm

Din tch tip xc v mt sn phm

Bao gi sn phm

Loi sn phm

3.1.3.1.Loi my ng

Loi my ng nh hng rt ln n thi gian lnh ng. V d, do c h s truyn

nhit b mt tt hn, mt sn phm s lnh ng trong my ng kiu nhng nhanh hn

trong my ng thi gi khi vn hnh cng mt nhit .

My ng cng lnh c cng mau ng. Khi da sn phm vo my ng, phi vn

hnh my trc cho nhit t ng xung thp (t

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Tng quan gia thi gian lnh

ng v vn tc gi trong my ng

qut gi

Tng quan tng qut gia tc

gi v thi gian lnh ng ( hnh bn)

cho thy thi gian lnh ng gim khi

tc gi gia tng.

3.1.3.3.Nhit vn hnh

Tuy nhin mi tng quan ny kh

phc tp v ty thuc mt s yu t. nu

lp khng kh t hm ngn cn truyn

nhit th nhng thay i v tc khng

kh s to nn nhng khc bit c ngha n

thi gian lnh ng. Nhng nu sn phm qu

to hay chnh thy sn l i tng cn tr

truyn nhit th nhng tc thay i khng kh s km ngha i. Nhit khng kh,

mt khng kh, m khng kh v hn lon khng kh l nhng yu t khc cng

cn c xem xt khi cp n yu t khng kh i vi thi gian lnh ng, tuy rng

mt s cc yu t ny ch c tc dng nh b m thi.

3.1.3.4.Nhit sn phm trc khi lm lnh ng

Sn phm cng m, thi gian lnh ng cng di. V vy thy sn nn gi lnh

trc khi lm lnh ng duy tr phm cht, ng thi gim thi gian lnh ng v yu

cu lm lnh.

3.1.3.5.B dy sn phm

Sn phm cng dy, thi gian lnh ng cng ko di. i vi nhng sn phm dy

di 50mm, nu tng gp i b dy c th lm thi gian lnh ng tng thm gp

i, trong khi tng gp i sn phm dy 100mm li ko di thi gian lnh ng gp 4

ln. V vy, t sut thay i thi gian lnh ng theo b dy ty vo mc quan trng

tng i ca lc cn ca thy sn i vi s truyn nhit.

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3.1.3.6.Hnh dng sn phm

Hnh dng thy sn hoc sn phm thy sn nh hng ng k n thi gian lm

lnh ng. Trong mt my ng dng lm lnh ng c ri tng con, loi c trn mnh

lnh ng trong 2/3 thi gian lm lnh ng loi c dp c b mt dy.

3.1.3.7.Din tch tip xc v mt sn phm

Trong my ng bn phng, tip xc km gia thy sn v bn phng lm tng thi

gian lnh ng. Tip xc km do ng trn bn phng, hp cha sn phm chng

chnh khng u, hp sn phm cha y hoc khong trng (l trng) trn mt khi

sn phm, dn n truyn nhit cho sn phm km. Nhng l trng lp mt khi sn

phm thng ko theo nhng l trng bn trong (intrenal voids) lm gim mt sn

phm (hay cht ca sn phm).

3.1.3.8.Bao gi sn phm

Phng php bao gi, loi v b dy vt liu bao gi nh hng ln n thi gian

lnh ng ca sn phm. Khng kh chn gia lp bao b v sn phm thng c nh

hng n thi gian ng lnh ln hn l lc cn ca vt liu bao gi. V d nh c xng

khi cha trong hp g c np y. Chy ng n 15 ting trong mt my ng thi gi.

C xng khi trong hp nhm cng dng, cng c v c np y ch chy ng trong 12

ting, nhng nu c trong hp g c g np th thi gian chy ng cn 8 ting v

khng c lp khng kh chn.

3.1.3.9.Loi sn phm

Hm lng m trong mt loi sn phm cng cao, hm lng nc cng thp. hu

ht nhit lng thi ra trong qu trnh ng lnh l chuyn nc thnh ; v vy, nu

c t nc th yu cu nhit lng tch ra lm ng thy sn s cng t. V hm lng

m ca c c du thay i theo ma nn thng s dng con s nhit lng ca c tht

trong tnh ton m bo an ton. iu ny m bo nng sut my ng ng yu cu,

bt lun ging loi c ng lnh l g.

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3.2.Nhng bin i ca thy sn sn trong qu trnh lm ng lnh.

3.2.1.Bin i vi sinh vt Khi thy sn h nhit xung im ng bng, vi sinh vt hot ng chm li. Xung

-100C vi trng cc loi khng pht trin c nhng men mc cha b c ch. Phi

xung n -150C men mc mi ngng pht trin. Do nhit di -150C s ngn

chn c vi trng ln men mc v khong nhit ny m thy sn ch xp x trn

di 10%. Tuy nhin, ngi ta thy rng nhit -200C vn cn vi loi vi trng sng

c.

Ngoi ra, khong nhit -1-50C gn nh a s nc t do ca t bo thy sn

kt tinh thnh . Nu lnh ng chm, cc tinh th nc to, sc lm v t bo vi trng

mnh nht giai on ny. Do phng php lnh ng chm tiu dit vi trng hn l

phng php lnh ng nhanh nhng li gy hi cho th cht ca sn phm.

3.2.2.Bin i ha hc

3.2.2.1.Bin i cht m

-200C cht m b ng li, sau 6 thng bo qun c phn gii nh.

khong nhit -1-50C, protein b bin tnh, c bit myosin b kt ta. thi

gian lnh ng cng ko di( chm) th protein cng b bin tnh. Lm lnh ng nhanh

s b bin tnh protein. Di -200C th protein hu nh khng bin tnh.

3.2.2.2.Bin i cht bo

C bo d b oxy ha cht bo. Cht bo b ha chua ( thy phn) v hm lng axit

bo th t do ph thuc vo nhit v thi gian bo qun. Nu nhit -120C sau 10

tun ch s peroxit tng ln r rt; sau 30 tun ch s ny vt qu quy nh v phm cht

v sinh. Tnh cht ha tan ca vitamin A trong m cng thay i, cht m s c li v

do.

3.2.2.3.Bin i gluxit

Khi lnh ng chm, glycogen phn gi ra nhiu axit lactic nhit thp hn l

trng hp lnh ng nhanh.

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3.2.2.4.Bin i vitamin

Vitamin t b mt i trong giai on ny, a s b mt trong giai on ch bin, ra.

nhit lnh, vitamin A t ra bn vng. Vitamin B2, PP mt mt t, vitamim C

mt nhiu khi sn phm mt nc, chy lnh. Vitamin E b hao ht ton b.

3.2.2.5.Bin i cht khong

Nhit lnh khng nh hng n khong cht nhng do s bin i c cht sn

phm khi lm ng lnh khin hao ht mt lng ln khong cht tan trong dch t bo

chy ra ngoi khi r ng.

3.2.3.Bin i l hc

3.2.3.1.Tng th tch

Nc trong thy sn ng bng lm tng th tch ln 10%.

3.2.3.2.Thay i mu sc

Do mt nc, cc sc t hemoglobin, mioglobin, hemoxyanin chuyn thnh

methemoglobin, motmioglobin v methemoxyanin lm mu sm li. Ngoi ra cho tc

lnh ng chm hay nhanh, tinh th bng hnh thnh ln hay nh m c tit x quang hc

khc nhau. Tinh th bng nh th thy sn ng lnh c mu nht hn l thy sn lnh

ng chm c tinh th bng to.

3.2.3.3.Gim trng lng

Thy sn lnh ng b gim trng lng do bc hi nc hoc do thit hi l hc

trong qu trnh lm ng lnh.

Thit hi l hc c th do xo ng trong khi lnh ng khin cho nhiu mnh nh

b v vn.

Thit hi l hc trong mt my ng khng ng k v khng hn 1% nu thc

hin lm lnh ng ng cch.

Ring vic gim trng lng do bc hi ty vo yu t nh loi my ng, thi

gian lnh ng, loi sn phm, c dng sn phm, tc khng kh v iu kin vn

hnh my.

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Hao ht do bc hi trong my ng bn phng khng nhiu bng hao ht trong my

ng qut gi, v my dng hi lnh trc tip nh nit v cacbonic. Tuy nhin vic gim

trng lng sn phm trong my ng nit, cacbonic s thp do thi gian lnh ng qu

ngn.

Mc gim trng lng ca thy sn nh cao hn thy sn ln. T sut hao ht t

l thun vi din tch tip xc b mt, m c nh li c tng din tch tip xc cao hn c

ln. Ngoi ra c ng tng con hao ht nhiu hn c ng lc.

Bao gi c khi ng lnh cng lm gim hao ht rt nhiu; nhng nu bao gi

khng cht, trng lng s dn b hao ht do bc hi b mt bn trong lp bao gi. Gi

sn phm s vn cn nguyn trng lng nhng bn trong lng nc b tch ra bt.

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TI LIU THAM KHO

1. Sch Cng ngh ch bin thc phm, L Vn Vit Mn, NXB HQG TP

H Ch Minh.

2. Sch Cc qu trnh c bn trong sn xut thc phm, NXB Gio Dc, 1996.

3. Sch Qu trnh v thit b truyn nhit, NXB HQG TP H Ch Minh.

4. http://tailieu.vn/tag/ky-thuat-dong-lanh-thuy-san.html

5. http://cnx.org/contents/m30642/latest

6. http://www.ebook.edu.vn/

7. http://www.savame.com/giao-trinh-he-thong-may-va-thiet-bi-lanh/