Do an San Pham Mi an Lien

GVHD: Ths. Nguyn Th Tho Minh

Ths. Phm Th Cm Hoa

SVTH: Trn Th Hng Nghim

Lp: 02DHDB2

MSSV: 2022110245TP. H Ch Minh, ngy 18 thng 05 nm 2014

GVHD: Ths. Nguyn Th Tho Minh

Ths. Phm Th Cm Hoa

SVTH: Trn Th Hng Nghim

Lp: 02DHDB2

MSSV: 2022110245TP. H Ch Minh, ngy 18 thng 05 nm 2014

MC LC

iMC LC

vLI CM N

viiDANH MC CH VIT TT

viiiDANH MC BNG

ixDANH MC HNH

CHNG 1: 1TNG QUAN V SAN PHM MI N LIN

11.1.Lch s ra i sn phm m n lin

11.2.Quy trnh sn xut m n lin

11.2.1.Quy trnh san xut mi n lin

31.2.2.Gii thch quy trnh cng ngh

CHNG 2: 6TIU CHUN CHO SAN PHM MI N LIN

62.1.Tiu chun Vit Nam cho m n lin - TCVN 5577 : 2004

62.1.1.Chi tiu cam quan cua san phm mi n lin

62.1.2.Ch tiu ha l cua san phm mi n lin

72.1.3.Ch tiu vi sinh vt cua san phm mi n lin

72.1.4.Ph gia thc phm

82.2.Tiu chun Codex cho m n lin

82.2.1.Chi tiu Cam quan

82.2.2.Tp cht

82.2.3.Yu cu phn tch cho vt mi

82.2.4.1. m

82.2.4.2.Gi tr acid.

82.2.4.Phu gia thc phm

9CHNG 3: CC PHNG PHP KIM TRA CC CH TIU SN PHM CA M N LIN

93.1.Phng php ly mu sn phm m n lin kim tra cc ch tiu theo TCVN 5777: 2004

93.1.1.Yu cu chung

93.1.2.Ly mu kim tra cc ch tiu cm quan

103.1.3.Ly mu kim tra cc ch tiu ha l

103.1.4.Ly mu kim tra cc ch tiu vi sinh vt

113.2.Phng php kim tra ch tiu cm quan ca m n lin theo TCVN 5577:2004

113.2.1.iu kin chung nh gi cm quan theo TCVN 5604: 1991

113.2.2.Kim tra bao gi, ghi nhn v khi lng

113.2.3.Xc nh cc ch tiu cm quan v mc chn ca vt m kh v cht lng ca vt m sau khi ngm trong nc si

113.3.Phng php kim tra cc ch tiu ha l ca m n lin

123.3.1.Phng php xc nh m ca vt m

123.3.1.1.Xc nh m ca vt m theo ISO 712: 1998

143.3.1.2.Xac inh m cua vt mi theo tiu chun Codex 249-2006

143.3.2.Xac inh ham lng tro khng tan trong HCl cua goi m theo TCVN 5777: 2004

173.3.3.Xc nh hm lng natri clorua ca vt m theo TCVN 4591:1988

183.3.4.Xc nh hm lng cht bo ca vt m theo TCVN 5777:2004

193.3.5.Xc nh ch s axit ca gi m

193.3.5.1.Xc nh ch s axit ca phn bo thu c trong gi m theo TCVN 6127: 2010

233.3.5.2.Xc nh ch s axit ca gi m theo tiu chun Codex 249-2006

243.3.6.Xc nh ch s peroxit ca gi m theo TCVN 6121: 2010

303.4.Phng php kim tra cc ch tiu vi sinh vt ca m n lin

313.4.1.Nguyn tc chung chun b mu th, huyn ph ban u v cc dung dch pha long kim tra cc ch tiu vi sinh vt ca m n lin theo TCVN 6507-1: 2005

353.4.2.Phng php kim tra tng vi sinh vt hiu kh trong m n lin

353.4.2.1.Phng php kim tra tng vi sinh vt hiu kh trong m n lin theo TCVN 4884: 2005

383.4.3.Phng php kim tra Coliforms v Escherichia coli trong m n lin

393.4.3.1.Phng php kim tra Coliforms trong m n lin theo TCVN 6848:2007

423.4.3.2.Phng php kim tra Escherichia coli trong m n lin theo TCVN 6846: 2007

523.4.3.3.Phng php kim tra Coliforms v Escherichia coli trong m n lin theo AOAC 990.11

543.4.4.Phng php kim tra Staphylococcus aureus trong m n lin

543.4.4.1.Phng php kim tra Staphylococcus aureus trong m n lin theo TCVN 4830-1:2005

623.4.4.2.Phng php kim tra Staphylococcus aureus trong m n lin theo TCVN 4830-2:2005

673.4.4.3.Staphylococcus aureus trong m n lin theo AOAC 987. 09

703.4.5.Phng php kim tra Clostridium perfringens trong m n lin

703.4.5.1.Phng php kim tra Clostridium perfringens trong m n lin theo TCVN 4991:2005

773.4.5.2.Phng php kim tra Clostridium perfringens trong m n lin theo AOAC 976.30

803.4.6.Phng php kim tra Bacillus cereus trong m n lin

803.4.6.1.Phng php kim tra Bacillus cereus trong m n lin theo TCVN 4992:2005

843.4.6.2.Phng php kim tra Bacillus cereus trong m n lin theo AOAC 980. 31.

873.4.7.Phng php kim tra Salmonella trong m n lin

873.4.7.1.Kim tra Salmonella trong m n lin theo TCVN 4829 : 2005

1003.4.7.2.Kim tra Salmonella trong m n lin theo AOAC 967.27

1023.4.8.Phng php kim tra tng s nm men v nm mc ca m n lin theo TCVN 8275-2:2010

1073.4.9.So snh cc phng php kim tra cc tiu chun ca sn phm m n lin theo cc tiu chun

111CHNG IV

111KT LUN V KIN NGH

1114.1.Kt lun

1114.2.Kin ngh

113TI LIU THAM KHO

TOC \o "1-1" \h \z \u 116PH LC

LI CM NTrong sut thi gian t khi bt u hc tp Trng i hc Cng Nghip Thc Phm Thnh Ph H Ch Minh n nay, em nhn c rt nhiu s quan tm, gip ca qu Thy C, gia nh v bn b. Vi lng bit n su sc nht, em xin gi n qu Thy C Khoa Cng Ngh Thc Phm cng vi tri thc v tm huyt ca mnh truyn t vn kin thc qu bu cho chng em trong sut thi gian hc tp ti trng.Em xin chn thnh cm n C Phm Th Cm Hoa v C Nguyn Th Tho Minh tn tm hng dn, gip em trong sut qu trnh thc hin n. ti n ca em l Sn phm m n lin, y l mt ti ni v cc ch tiu cht lng cn kim tra i vi mt sn phm m n lin m bo sn phm t cht lng v an ton trc khi phn phi trn th trng. L do em chn ti ny l v hin nay m n lin ang l sn phm c tiu th rt nhiu Vit Nam. Ngy cng nhiu nhn hiu m n lin ra i, thm ch c c nhng loi m n lin khng c nhn hiu c by bn. Do , vic m bo cht lng v an ton thc phm i vi sn phm m n lin l cng vic thit yu bo v sc khe ngi tiu dng khi tiu th sn phm trong thi gian lu di. n phn tch thc phm ny c thc hin trong thi gian 4 tun. Bc u i vo thc t, tm hiu v cc phng php phn tch theo cc tiu chun, em thy kin thc ca mnh cn nhiu hn ch. Do vy, khng trnh khi nhng thiu st l iu chc chn, em rt mong nhn c nhng kin ng gp qu bu ca qu Thy C v cc bn hc cng nghnh kin thc ca em trong lnh vc ny c hon thin hn.Sau cng, em xin knh chc qu Thy C trong Khoa Cng Ngh Thc Phm v ton th qu Thy C trong trng tht di do sc khe, nim tin tip tc thc hin s mnh cao p ca mnh l truyn t kin thc cho th h mai sau.

Thnh ph H Ch Minh, ngy 16 thng 05 nm 2014

Sinh vin thc hinTrn Th Hng NghimNHN XT CA GIO VIN HNG DN

TP. H Ch Minh, ngy thng 05 nm 2014

DANH MC CH VIT TT

AOAC: Association of Official Analytical Chemists (Hip hi cc nh ho phn tch chnh thng).MPN: Most Probable NumberTCVN: Tiu chun Vit NamDANH MC BNG

6Bng 2.1. Yu cu cm quan ca vt m

6Bng 2.2. Cc ch tiu ha l ca m n lin

7Bng 2.3. Cc ch tiu vi sinh vt ca gi m

9Bng 3.1. S lng mu ly kim tra thng v mc cht lng chp nhn

10Bng 3.2. S lng mu ly kim tra trng ti hoc nh gi chng nhn sn phm ph hp TCVN 5777: 2004 v mc cht lng cho php

11Bng 3.3. Bng cc phng php kim tra cc ch tiu ha l ca sn phm

21Bng 3.4. Khi lng ca phn mu th v nng ca dung dch kim

30Bng 3.5. Bng cc phng php kim tra cc ch tiu vi sinh vt ca m n lin

48Bng 3.5. Bng MPN

97Bng 3.6. Gii thch cc php th sinh ho khng nh Salmonella

100Bng 3.7. Gii thch cc kt qu cc php th khng huyt thanh khng nh Salmonella

DANH MC HNH

2Hnh 1.1. S khi quy trinh cng ngh san xut mi n lin.

53Hnh 3.1. Hnh thit b s dng mng li lc k nc.

69Hnh 3.2. Bng gi tr MPN.

CHNG 1TNG QUAN V SAN PHM MI N LIN1.1. Lch s ra i sn phm m n linSau chin tranh th gii th II, khi chng kin cnh ngi dn Nht Bn ni ui nhau ch mua nhng t m di tri m rt lnh, ng Momofuku Ando c mong v s an bnh cho t nc: Ha bnh s n khi ngi dn c ci n. V chnh t nhng khonh khc ngn ngi cng t tng ln lao em n cho ng nim tin, s quyt tm pht minh ra loi m tin dng c th thng thc ti nh ngay sau khi cho nc nng vo, m ngy nay c gi l m n lin.Vo nm 1958, m n lin v g Chicken Ramen ln u tin c ra i, l mt pht minh tin phong gy nhiu sng st v l nim t ho ca ngi dn Nht Bn, mang n s tin dng hn bao gi ht. Ngy nay, m n lin tr nn rt quen thuc vi ngi dn ca nhiu nc trn th gii nh tnh tin dng ca sn phm.

1.2. Quy trnh sn xut m n linCng ngh sn xut m n lin pht trin ti mc kh hon chnh vi rt nhiu quy trnh khc nhau ty theo nguyn liu, sn phm v quy m sn xut. Tuy nhin, tt c cc quy trnh u qua ba giai on chnh l nho trn, to hnh v x l nhit.

1.2.1. Quy trnh san xut mi n lin

Hnh 1.1. S khi quy trinh cng ngh san xut mi n lin.

1.2.2. Gii thch quy trnh cng ngh1.2.2.1. Giai on nho trn bt

Mc ch to c khi bt nho thch hp cho qu trnh to hnh tip theo.

Bt m s c trn kh vi cc bt khc (nu c). Mui, nc, mu v cc nguyn liu ph khc nh trng, bt c chua, vitamin, c ha tan u trong nc, chnh n nhit thch hp v phun t t vo ci trn bt kh. Tin hnh nho trn cho n khi hn hp bt to thnh khi bt nho nng nht.

1.2.2.2. Giai on to hnh

Mc ch to cho sn phm m c hnh dng thch hp theo yu cu.

To hnh si m n lin c thc hin bng phng php cn ct. Cn ct c thc hin theo trnh t dt khi bt thnh tng tm, cn n mng thch hp. Sau , cc tm bt s c ct hay dp to hnh si m theo kch thc mong mun.1.2.2.3. Giai on x l nhita) Qu trnh hp

Mc ch lm chn s b si m rt ngn thi gian chin, c nh cu trc si m.

Trong cng nghip, m s c chy trn li ti i qua bung hp hnh hp ch nht. Trong bung hp, m s c gia nhit nh hi nc c phun ra t cc ng dn hi b tr dc theo chiu di bung hp.b) Qu trnh thi ngui

Mc ch chun b cho qu trnh ti gia v.

Sau khi ra khi bung hp, li ti m s i qua h thng qut thi ngui lm ro phn nc t do ng li trn b mt si m. Thi ngui cng gip cho nhng si m b h ha dnh vo li ca bng ti c tch ra khi li ti. V vy, cc qut thi ngui thng c gn bn di ca li ti.c) Qu trnh ct nh lng

Mc ch ct bng m ra thnh tng ming c trng lng nht nh v to hnh cho vt m.

S dng thit b ct gm hai trc quay ngc chiu nhau, trong c mt trc c gn li dao ct m, trc cn li c tc dng nh mt tm k.d) Qu trnh ti gia v

Mc ch nhm hon thin sn phm, to hng v c trng v mu sc ca vt m, tng gi tr cm quan ca si m

Nc lo c ti ln li ti cha cc vt m thng qua mt h thng vi phun sng sao cho gia v c th thm u c hai mt ca vt m trnh hin tng sn phm sau khi chin s c hai mu.e) Qu trnh qut ro

Mc ch chun b cho qu trnh chin m.

Si m c ti gia v s c qua mt h thng qut gim nhanh m ca si m. Qu trnh ny gip cho si m kh hn trc khi a vo chin, nh s gim c lng cht bo c trong thnh phm.f) Qu trnh v khun

Mc ch to hnh dng ng nht cho sn phm, chun b cho qu trnh chin.

Cc khun c dng hnh trn, ch nht hay hnh chn, ly ty thuc vo dng bao gi sn phm sau ny. Khun c gn trn xch ti v kt hp cng vi np nhm y kn v c nh vt m.g) Qu trnh chin

Mc ch ch bin v bo qun sn phm.

Shortening c gia nhit gin tip bng mt thit b trao i nhit trc khi cho vo cho chin, c tun hon lin tc gia thit b trao i nhit v cho chin. Trong qu trnh bm du s c qua thit b lc th v lc tinh loi b m vn v chy. Sau mt thi gian chin, shortening s chuyn sang mu nu m, c, c mi du kht th cn loi b.

1.2.2.4. Giai on hon thin sn phm

Mc ch hon thin sn phm.

H thng lm ngui l mt bung di hnh hp ch nht, c gn h thng qut thi khng kh. M sau khi chin s c bng ti li a vo h thng lm ngui. hai u h thng, cc qut s ht khng kh t ngoi vo, thi kh t pha di hng ln trn v thng qua cc l trn mt li lm kh vt m. Pha trn li ti b tr cc qut ht ht kh nng trong hp qua ng ng thi ra ngoi.

Sau khi lm ngui, m s theo bng ti vo h thng ng gi.CHNG 2TIU CHUN CHO SAN PHM MI N LIN

2.1. Tiu chun Vit Nam cho m n lin - TCVN 5577 : 2004

Tiu chun ny p dng cho cc loi m n lin c ng gi sn, c hoc khng km theo gi gia v, hoc m c trn / phun sn gia v; c th n lin hoc n lin sau khi ngm trong nc si trong thi gian xc nh

M n lin (instants noodles): l sn phm c ch bin t thnh phn chnh l bt m, c hoc khng thm cc thnh phn khc. M n lin c c trng bng vic s dng qu trnh h ha s b (lm chn), sau tch nc bng cch chin, hoc bng cch khc (m khng chin).2.1.1. Chi tiu cam quan cua san phm mi n lin

Bng 2.1. Yu cu cm quan ca vt m

Ch tiuYu cu

1. Mu scng nht, c trng cho tng loi sn phm, khng b chy, hai mt t s khc bit.

2. Mi vc trng cho tng loi sn phm, n khng thy sng, khng c mi v l nh mc, kht, v cht

3. Trng thiDng khi hoc c hnh dng xc nh, ng u v ph hp vi tng loi bao b, khng vn nt, khng c vt l; sau khi ngm trong nc si theo hng dn ca nh sn xut, si m khng b t, nt, khng dnh.

Yu cu ngoi quan i vi gi gia v: Phi kn, kh v sch. 2.1.2. Ch tiu ha l cua san phm mi n linBng 2.2. Cc ch tiu ha l ca m n linCh tiuGii hn ti a

M chinM khng chin

1. m ca vt m, % khi lng5,012,5

2. Hm lng cht bo ca vt m, % khi lng20-

3. Ch s axit ca gi m, mg KOH/g cht bo chit ra t vt m v cc gi gia v2,0-

4. Ch s peroxit ca gi m, meq/kg cht bo chit ra t vt m v cc gi gia v20-

5. Hm lng natri clorua (NaCl) ca vt m, % khi lng2,5

6. Hm lng tro khng tan trong axit clohydric (HCl) ca gi m, % khi lng0,1

2.1.3. Ch tiu vi sinh vt cua san phm mi n linBng 2.3. Cc ch tiu vi sinh vt ca gi mTn ch tiuMc ti a

1. Tng s vi sinh vt hiu kh trong 1 g sn phm104

2. S Coliforms trong 1 g sn phm10

3. S Escherichia Coli trong 1 g sn phm3

4. S Staphylococcus aureus trong 1 g sn phm10

5. S Clostridium Perfringens trong 1 g sn phm10

6. S Bacillus Cereus trong 1 g sn phm10

7. S Salmonella trong 25 g sn phmKhng c c

8. Tng s nm men, nm mc trong 1 g sn phm102

2.1.4. Ph gia thc phm

S dng cc cht ph gia thc phm theo quy nh hin hnh. Theo thng t 27/2012/TT-BYT. Thng t hng dn vic qun l ph gia. [19 ]2.2. Tiu chun Codex cho m n lin (Codex stan 249-2006) [26]

Mi n lin (instant noodles) la san phm c ch bin t thanh phn chinh la bt mi, hoc bt gao, hoc bt hay tinh bt khac, co hoc khng co thm cac thanh phn khac. No co th c x ly bi cac tac nhn kim.

Mi n lin c c trng bng vic s dung qua trinh h hoa s b va tach nc bng cach chin, hoc bng cach khac. Sn phm nn c trnh by theo mt trong nhng cch sau y: - m chin, hoc - m khng chin.2.2.1. Chi tiu Cam quan

Nhng c tinh hnh dang, kt cu, mi thm, hng v v mu sc phai phu hp vi loai san phm mi n lin.2.2.2. Tp cht

Sn phm phi khng co tap cht t bn ngoai. 2.2.3. Yu cu phn tch cho vt mi (khng bao gm goi gia vi) 2.2.4.1. m

Ti a l 10% i vi m xo

Ti a l 14% cho m khng chin 2.2.4.2. Gi tr acid: ti a l 2mg KOH/g du (ch p dng cho m xo).2.2.4. Phu gia thc phm

Vic s dng ph gia thc phm c thc hin theo mc ti a cho php ca cc tiu chun chung i vi ph gia thc phm theo Tiu chun Codex 192-1995. [26].

CHNG 3

CAC PHNG PHAP KIM TRA CAC CHI TIU CUA SAN PHM

MI N LIN

3.1. Phng php ly mu sn phm m n lin kim tra cc ch tiu theo TCVN 5777: 20043.1.1. Yu cu chung

Mu c ly theo tng l hng. L hng l mt lng cc n v bao gi m n lin nht nh cng tn gi, cng loi, cng nhn hiu hng ha, c ng trong cng mt loi bao gi, c sn xut trong cng mt thi gian bi cng mt c s sn xut v c giao nhn cng mt t.

n v bao gi m n lin l n v bao gi trc tip nh: gi, hp, ly

Khi lng mi l hng do cc bn lin quan tha thun.

Trong khi ly mu phi quan st nhn hiu hng ha, tnh trng bao b ca l hng v ghi li kt qu quan st. Khi ly mu cn lp bin bn ly mu vi cc thng tin cn thit.

3.1.2. Ly mu kim tra cc ch tiu cm quan3.1.2.1. Kim tra thng Bng 3.1. S lng mu ly kim tra thng v mc cht lng chp nhn

C l

(S n v bao gi trong mt l)C mu

(S n v bao gi c ly)Mc cht lng chp nhn

(S n v bao gi chp nhn c khuyt tt)

( 4 80061

4 801 24 000132

24 001 48 000213

48 001 84 000294

84 001 144 000385

144 001 240 000486

> 240 000607

3.1.2.2. Kim tra trng ti hoc nh gi chng nhn sn phm ph hp tiu chun nyBng 3.2. S lng mu ly kim tra trng ti hoc nh gi chng nhn sn phm ph hp TCVN 5777: 2004 v mc cht lng cho phpC l

(S n v bao gi trong mt l)C mu

(S n v bao gi c ly)Mc cht lng chp nhn

(S n v bao gi chp nhn c khuyt tt)

( 4 800132

4 801 24 000213

24 001 48 000294

48 001 84 000385

84 001 144 000486

144 001 240 000607

> 240 000728

3.1.3. Ly mu kim tra cc ch tiu ha l

Ly ngu nhin 18 n v bao gi chia lm 2 nhm mu:- Nhm I: 9 n v bao gi dng phn tch.- Nhm II: 9 n v bao gi dng lu.

T nhm I, chia lm 2 nhm mu:- Nhm A: 3 n v bao gi dng phn tch cc ch tiu ca vt m. - Nhm B: 6 n v bao gi dng phn tch cc ch tiu ca gi m.3.1.4. Ly mu kim tra cc ch tiu vi sinh vt

Ly 20 n v bao gi cn li trong tng s 38 n v bao gi v chia lm 2 nhm mu.- Nhm III: 10 n v bao gi dng phn tch.- Nhm IV: 10 n v bao gi dng lu.

Trong giao dch thng mi, cc bn lin quan c th tha thun phng n ly mu khc.3.2. Phng php kim tra ch tiu cm quan ca m n lin theo TCVN 5577:20043.2.1. iu kin chung nh gi cm quan theo TCVN 5604: 1991 [11]

3.2.2. Kim tra bao gi, ghi nhn v khi lng

Kim tra bao gi, ghi nhn v khi lng tnh c tin hnh i vi tng n v bao gi.

3.2.3. Xc nh cc ch tiu cm quan v mc chn ca vt m kh v cht lng ca vt m sau khi ngm trong nc si3.2.3.1. Xc nh cc ch tiu cm quan

Sau khi tin hnh kim tra bao gi, ghi nhn v khi lng tnh, ly 3 n v bao gi kim tra cc ch tiu cm quan. Mi n v bao gi l mt mu th ring bit.

3.2.3.2. Xc nh mc chn ca vt m kh v cht lng ca vt m sau khi ngm trong nc si

T mi n v bao gi m n lin, b mt ming m kh, n th xc nh mc chn ca vt m, ghi li nhn xt. Cho phn cn li ca vt m vo bt, cho nc si vo, y np li, sau thi gian xc nh m np y bt m, quan st, n th v ghi li nhn xt i vi si m (lng nc si v thi gian ngm trong nc si theo hng dn ca nh sn xut ghi trn bao b).

i vi gi m c km theo gi gia v, tin hnh nh trn nhng trc khi ngm trong nc si th cho gi gia v vo bt cng vi vt m. Tin hnh nh gi v ghi li nhn xt mi v ca vt m v nc dng.3.3. Phng php kim tra cc ch tiu ha l ca m n lin

Bng 3.3. Bng cc phng php kim tra cc ch tiu ha l ca sn phm m n linTn ch tiuTiu chun Vit NamTiu chun tng ng

1. Xc nh m ca vt mISO 712: 1998Tiu chun Codex 249 - 2006

2. Xc nh hm lng tro khng tan trong HCl ca gi mTCVN 5777: 2004

3. Xc nh hm lng natri clorua ca vt mTCVN 4591: 1988

4. Xc nh hm lng cht bo ca vt mTCVN 5777: 2004

5. Xc nh ch s acid trong phn bo thu c ca gi mTCVN 6127: 1996

Thay th bng TCVN 6127: 2010ISO 660: 2009

6. Xc nh ch s peroxit trong phn cht bo thu cTCVN 6121: 1996

Thay th bng TCVN 6121: 2010ISO 3960: 2007

3.3.1. Phng php xc nh m ca vt m3.3.1.1. Xc nh m ca vt m theo ISO 712: 1998 [27]a) Nguyn tc

Nu cn thit, mu c nghin mn, sau x l s b, khi c yu cu. Mu kim tra c sy kh nhit 130oC 3oC, trong iu kin cho php mt kt qu thu c l ph hp theo phng php ca ti liu tham kho c bn.b) Thit b

Thit b thng thng trong phng th nghim [14] v c bit sau y:

- Cn phn tch, c th cn vi chnh xc 0,001 g- My nghin, c cc c im sau

+ lm bng vt liu m khng hp th m

+ d dng lm sch v c t khong trng cng tt;

+ cho php vic nghin thc hin nhanh chng v thng nht, khng c s gia tng ng k ca nhit v khng tip xc vi khng kh bn ngoi;

+ iu chnh c c cc ht c kch thc quy nh.

- a kim loi, khng b n mn di nhng iu kin kim tra, a thy tinh, c np y m kht v c din tch b mt hiu qu to iu kin cho cc phn th nghim c phn phi cung cp cho mt khi lng trn mt n v din tch khng qu 0,3 g/cm3.

- L sy lin tc, chy bng in, c kh nng c kim sot theo cch , trong thi gian lm vic bnh thng, nhit ca khng kh v ca cc k mang cc phn mu l 130oC 3C trong khu vc ca cc phn kim tra.

L c cng sut nhit nh vy, khi ban u ci t nhit 131oC, n c th t c nhit ny trong vng cha y 30 pht sau khi t s lng ti a cc phn kim tra c th c sy kh cng mt lc.- Bnh ht m, cha cht ht m hiu qu.

c) Cch tin hnh (3.2.2 [20])

iu chnh my (ci) nghin nhn c mnh sau khi nghin lt ht qua sng l vung c kch thc 1,7 mm x 1,7 mm. Nghin 1 lng mu nh v b i. Sau tin hnh nghin nhanh v cn ngay khong 5 g mu th. Cn lng mu nghin vi chnh xc n 0,001 g. Cho vo chn cn c np (chn cn v np c sy trc n khi lng khng i v cn vi chnh xc n 0,001 g). t chn v m np bn cnh vo t sy. Tin hnh sy mu nhit 130oC ( 3oC trong vng 120 pht ( 5 pht k t khi t sy t c 130oC ( 3oC.

Ly nhanh chn cn ra khi t sy, y np v t vo bnh ht m. Sau khong 30 n 45 pht khi chn ngui n nhit phng th em cn vi chnh xc n 0,001 g.d) Tnh kt qu (3.2.2 [20])

m ca vt m (W) tnh bng phn trm, c xc nh theo cng thc:

Trong :m1 l khi lng mu trc khi sy, tnh bng gam.

m2 l khi lng mu sau khi sy, tnh bng gam.

Kt qu php th l tr s trung bnh cng ca 2 ln xc nh v c tnh n s l th nht sau du phy.

3.3.1.2. Xac inh m cua vt mi theo tiu chun Codex 249-2006a) Thit b

- a nhm: ng knh 55 mm, chiu cao 15 mm v vi np y cht.

- L nung: vi chnh xc n 1oC.

- Bnh ht m: silica gel nhit 150oC l tc nhn sy kh t yu cu.

b) Cch tin hnh

Chuyn m vao ti nha ngn chn s thay i m, v sau lam nho thnh cc mnh nh bng tay hoc ba g chn mi a lam nho trong phm vi kch thc 2,36 mm n 1,7 mm bng cch s dng hai sng vi kich thc l la 2.36mm v 1.7mm (kch thc mt li 12-8), v trn u, va s dng cho cac mu th nghim. Nu m l qu mng sng lc vi sng, ct thnh 1-2 cm chiu di, trn u, v s dng cc m a ct cho mu th nghim.

i vi m chin:

Lm lnh v cn a (c np y), trc un nng n 105C, cn khong 2 g hn hp mu th chnh xc n 1mg. Cho phn th nghim vo a kh v y np cho vo l nung 2 h trong l m thng gi v duy tr 105C. (Thi gian kh 2 gi bt u khi nhit l nung t 105C.) Sau khi sy, chuyn a v mu sy sang bnh ht m, v cn chnh xc ti 1 mg ngay sau khi t nhit phng. Bo co s hao ht trng lng l m (phng php gin tip).

i vi m khng chin:

i vi m khng chin, thc hin tng t nh m chin, nhng sy mu th trong 4 gi.

c) Tnh kt qu

Tnh ton bng cch s dng phng trnh sau:

m (%) = {(g phn mu trc khi sy g phn mu sau khi sy) / g phn mu trc khi sy}100.

3.3.2. Xac inh ham lng tro khng tan trong HCl cua goi m theo TCVN 5777: 20043.3.2.1. Thit b, dng c

S dng cc thit b, dng c thng thng trong phng th nghim [ph lc V] v:

- Cn phn tch, c th cn chnh xc n 0,0001g.

- L nung, duy tr nhit 5000C n 5500C.

- Cc thy tinh chu nhit c mt knh ng h, dung tch 250 ml.

- Kp st.

- Bp in.

- Bnh ht m.

-Giy lc khng tro.

- Phu thy tinh.

- Chn nung bng s chu nhit hoc bch kim, dung tch t 30 ml n 50 ml.

3.3.2.2. Thuc th

- Nc ct, hoc nc c cht lng tng ng.

- Dung dch axit clohydric (HCl) 10%.

- Dung dch bc nitrat (AgNO3) 5%.

- Axit nitric (HNO3) m c, d = 1,40 g/ml.

3.3.2.3. Cch tin hnh

Xc nh hm lng tro tng s:

t chn nung vo l nung v nung trong 1 gi nhit t 5000C n 5500C. Dng kp st ly chn nung ra v lm ngui trong bnh ht m. Cn chn nung chnh xc n 0,0001g.

Cn 5g mu chnh xc n 0,0001g cho vo chn nung bit trc khi lng. Dn u mu trn y chn v t cn thn trn bp in cho n khi mu ht bc khi, sau nung nhit 5000C n 5500C trong khong t 3 gi n 5 gi. Nu mu cha c tro ha hon ton th nung thm 1 gi na. Nu mu vn cha c tro ha hon ton th lm ngui tro, thm t bng vi git nc ct v thm t 10 git n 15 git axit nitric m c. t chn nung ln bp in cho bay hi ht axit, sau li t vo l nung v nung nhit t 5000C n 5500C n khi mu c tro ha hon ton. Lm ngui trong bnh ht m v cn.

Lm li qu trnh nung mu cho n khi c khi lng khng i.

Xc nh hm lng tro khng tan trong axit HCl:

Ha tan tro ng trong chn nung bng 50 ml dung dch HCl 10%, sau chuyn ton b dung dch sang cc thy tinh chu nhit dung tch 250 ml y mt knh ng h v un trn bp in n si trong khong 15 pht (k t lc bt u si), ly ra ngui v lc qua giy lc khng tro.

Ra cc thy tinh chu nhit v giy lc mt vi ln bng nc ct nng cho n khi nc lc khng cn vt Cl (th bng dung dch AgNO3).

t cn thn giy lc cng cn vo mt chn nung khc c nung trc v cn chnh xc n 0,0001g, t trn bp in cho bay ht hi nc, sau t chy dn dn giy lc cng cn ngay trn bp in cho n khi khng cn khi bay ra. t chn nung cng vi cn vo l nung nhit t 5000C n 5500C. Sau mt gi ly chn nung ra, lm ngui trong bnh ht m v cn chnh xc n 0,0001g.

Cho chn nung vo l nung v nung nhit trn trong 30 pht ri lm ngui v cn. Lp li cc thao tc ny cho n khi khi lng chn nung cng cn khng i.

Tin hnh th mu trng nh trn bng cch dng tt c cc thuc th nhng s dng nc ct thay cho phn mu th.3.3.2.4. Tnh kt qu

Hm lng tro khng tan trong axit clohydric, X1, tnh theo % khi lng, s dng cng thc sau:X1 = x100

Trong :

G1 l khi lng chn nung c tro khng tan, tnh bng gam;

G2 l khi lng chn nung rng, tnh bng gam;

G l khi lng mu th, tnh bng gam.

Kt qu l trung bnh cng ca hai kt qu th song song. Chnh lch gia hai kt qu th song song khng c vt qu 0,02%.

3.3.3. Xc nh hm lng natri clorua ca vt m theo TCVN 4591:1988

3.3.3.1. Nguyn tc

Chit mui n khi mu bng nc nng, chun lng ion Clo bng bc nitrat vi ch th kalicromat.3.3.3.2. Dng c, ho cht- Cn phn tch chnh xc n 0,0001g;

- Bnh tam gic dung tch 250ml;

- Bnh nh mc dung tch 250ml;

- Cc t c m;

- Phu thy tinh ng knh 8cm;

- Giy lc gp np;

- Bp cch thu;

- Pipet 10, 25ml;

- Buret 25ml;

- Natri hydroxit 0,1N;

- Phenolphtalein 0,1%;

- Bc nitrat 0,1N;

- Kalicromat 5%.


Cn trn cn phn tch 10 - 20g mu chun b. Chuyn ton b mu vo bnh tam gic 250ml, trng k cc cn bng nc ct. Lng nc cho vo bnh chim 1/2 th tch. un bnh mu trn bp cch thu trong 15 pht. Ly mu ra lm ngui. Chuyn ton b mu sang bnh nh mc, thm nc ct n vch mc, lc k lng. Lc mu trn phu vi giy lc xp np. Thu dch lc. Ht 25ml dch lc cho vo bnh tam gic trung ho dch lc bng natri hydroxit 0,1N vi ch th phenolphtalein 0,1%. Thm vo bnh mu 10 git dung dch kalicromat 5% chun dch lc bng dung dch bc nitrat 0,1N cho n khi xut hin kt ta mu gch ca bc cromat. Ghi s ml bc nitrat dng.3.3.3.4. Tnh kt qu

Hm lng mui (X) tnh bng % theo cng thc:

Trong : 0,00585 - khi lng natri clorua tng ng vi 1ml dung dch bc nitrat 0,1N;V - th tch bc nitrat dng chun , ml;V1 - dung tch bnh nh mc, ml;V2 - th tch dch lc ht dng chun , ml;m - lng cn mu, g.

Kt qu l trung bnh cng ca kt qu 2 ln xc nh song song. Tnh chnh xc n 0,01%.

Chnh lch gia kt qu 2 ln xc nh song song khng ln hn 0,02%.3.3.4. Xc nh hm lng cht bo ca vt m theo TCVN 5777:20043.3.4.1. Thit b, dng c

S dng cc thit b, dng c thng thng trong phng th nghim v:

- B chit cht bo Soxhlet.

- Bp cch thy.

- Bng thy tinh hoc bng thm nc.

- Bnh ht m.

- T sy.

- Hp nhm, dng xc nh m.

- ng giy.

- Cn phn tch, c th cn chnh xc n 0,0001g.

- B chng ct.

3.3.4.2. Thuc th

Ete etylic hoc ete du ha c nhit si t 40oC n 75oC.


Cn 2g mu chnh xc n 0,0001g cho vo hp nhm v sy bng t sy nhit t 95oC n 100oC trong vng 1 gi. Ly ra ngui trong bnh ht m. Sau chuyn ton b mu vo ng giy. Dng bng c thm ete lau sch mu cn li trong hp nhm v y ming bng ln trn ng giy, cho ng giy vo trong ng chit ca b Soxhlet. Lp bnh cu sch c sy kh v bit trc khi lng vo b chit. Cho nc lnh chy lin tc vo ng sinh hn. Rt ete vo ng chit v ete chy trn xung bnh cu sao cho lng ete chim khong hai phn ba th tch bnh cu. un t t bnh cu trn bp cch thy n nhit si ca dung mi.

Tin hnh chit trong khong t 8 gi n 10 gi vi iu kin l trong 1 gi khng t hn 5 n 6 ln v khng nhiu hn 8 n 10 ln ete trn vo bnh cu.

Sau khi chit hon ton cht bo, ly bnh cu ra. Ct thu hi hon ton dung mi trong bnh. Cho bnh cu vo trong t sy v sy nhit t 100oC n 105oC trong 1 gi 30 pht. Ly bnh cu ra, lm ngui trong bnh ht m v cn.

3.3.4.4. Tnh kt qu

Hm lng cht bo, X2, tnh theo % cht kh, s dng cng thc sau:

X2 =

Trong :

G1 l khi lng bnh cu v cht bo, tnh bng gam;

G2 l khi lng bnh cu rng, tnh bng gam;

G l khi lng mu th, tnh bng gam;W l m mu th.

Kt qu cui cng l trung bnh cng ca hai kt qu th song song.

3.3.5. Xc nh ch s axit ca gi m

3.3.5.1. Xc nh ch s axit ca phn bo thu c trong gi m theo TCVN 6127: 2010

Tr s axit (acid value) (mg/g) l s miligam kali hydroxit dng trung ha cc axit bo t do c trong 1 g cht bo, khi c xc nh theo quy trnh quy nh trong tiu chun ny.a) Tch cht bo t gi m

Theo mc 3.3.4.3.

b) Nguyn tc

Mu th c ha tan trong hn hp dung mi thch hp v cc axit c mt c chun bng dung dch kali hoc natri hydroxit trong etanol hoc trong metanol.c) Thit b

S dng cc thit b, dng c ca phng th nghim thng thng [14] v c th nh sau:- Buret, dung tch 10 ml, c chia vch n 0,02 ml.- Buret, dung tch 25 ml, c chia vch n 0,05 ml.- Cn phn tch, c th c chnh xc n 0,001 g.- Dng c chun t ng hoc my o in th.- in cc pH kt hp, dng chun axit/baz khng nc.- Bnh nh mc, dung tch 1000 ml.d) Ha cht

Ch s dng cc thuc th loi tinh khit phn tch, tr khi c quy nh khc.- Dung mi A dng cho hn hp dung mi: etanol, ( ( 96 % th tch. C th s dng propan-2-ol ( ( 99 % th tch thay th cho etanol.- Dung mi B dng cho hn hp dung mi: dietyl ete, khng cha peroxit.C th s dng ter-butyl metyl ete, du nh (di si t 40oC n 60oC) hoc toluen thay th cho dietyl ete.

CNH BO Dietyl ete rt d chy v c th to thnh cc peroxit gy n. Ht sc cn thn khi s dng.

- Hn hp dung mi, trn cc th tch bng nhau ca cc dung mi A v dung mi B (v d ( A = 50 ml/100 ml v ( B = 50 ml/100 ml).

Ngay trc khi s dng, trung ha bng cch thm dung dch kali hydroxit vi s c mt ca 0,3 ml dung dch phenolphtalein i vi 100 ml hn hp dung mi.

C th s dng dung mi propan-2-ol chun vi dung dch KOH.- Etanol hoc metanol, ti thiu ( = 95 % th tch.- Natri hydroxit hoc kali hydroxit, dung dch chun trong metanol hoc etanol c nng cht c(NaOH) hoc c(KOH) = 0,1 mol/l v 0,5 mol/l. Nng phi c kim tra bng dung dch chun HCl.

CH THCH: Dung dch natri hydroxit hoc kali hydroxit trong metanol hoc etanol c th c thay bng dung dch natri hydroxit hoc kali hydroxit, ch khi lng nc a vo khng lm tch pha.- Phenolphtalein, dung dch trong etanol, nng khi lng p = 1 g/100 ml.- Thymolphtalein, dung dch trong etanol, nng khi lng p = 2 g/100 ml.- Alkali blue 6B, dung dch trong etanol, nng khi lng p = 2 g/100 ml.

i vi cc cht bo c mu m, th phi s dng alkali blue hoc thymolphtalein.- Nc, ph hp vi loi 3 ca TCVN 4851 [6].e) Cch thc hin

Phng php dung mi lnh s dng cht ch th (Phng php chun):

Ty thuc vo tr s axit d kin, chn khi lng phn mu th v nng kim theo bng 3.4.

Cn phn mu th theo bng 3.4 cho vo bnh nn 250 ml.

Thm t 50 ml n 100 ml hn hp dung mi trung ha v ha tan phn mu th bng cch lm nng nh, nu cn.

i vi cc mu c im tan chy cao, th s dng hn hp etanol-toluen.

Sau khi thm cht ch th, chun bng dung dch chun kali hydroxit trong khi xoay bnh lin tc. Vic chun c coi l kt thc khi thm mt git kim s to ra mu nh nhng vic i mu n nh trong t nht 15 s.

Phng php dung mi lnh s dng chun in th (Phng php chun):

Cn phn mu th theo bng sau cho vo cc c m 150 ml.Bng 3.4. Khi lng ca phn mu th v nng ca dung dch kim

Nhm sn phm

(cc v d)Tr s axit xp xKhi lng phn mu thNng KOH chnh xc ca php cn phn mu th

gmol/lg

Du thc vt tinh luyn

M ng vtt 0 n 1200,10,05

Du thc vt kh

M ng vt loi k thutt 1 n 4

t 4 n 1510

2,50,1

0,10,02

0,01

Axit bo gc x phngt 15 n 750,5

3,00,1

0,50,001

Axit bo k thut> 750,2

1,00,1

0,50,001

Thm t 50 ml n 100 ml hn hp dung mi trung ha v ha tan mu, lm nng nh, nu cn. i vi cc mu c im tan chy cao th s dng hn hp etanol-toluen.

a in cc kt hp vo hn hp dung mi v ni in cc vi dng c chun t ng.

Bt my khuy t nht 30 s v chun bng dung dch kali hydroxit chun trong khi vn khuy lin tc.

Ngay khi t c im tng ng ghi li lng dung dch chun s dng.

Phng php dng etanol nng c s dng cht ch th:

cc iu kin quy nh trong phng php ny, nu c mt cc axit bo mch ngn th chng l loi bay hi.

Cn mt lng mu th theo bng 3.4, ty theo mu sc v tr s axit d kin cho vo bnh cu th nht.

un n si 50 ml etanol cha 0,5 ml cht ch th phenolphtalein cho vo bnh cu th hai. Khi nhit ca etanol vn cn cao hn 70oC, th trung ha cn thn bng dung dch natri hydroxit hoc kali hydroxit 0,1 mol/l.

Vic chun c coi l kt thc khi thm mt git kim s to mu nh nhng vic i mu n nh trong t nht 15 s.

C th cn n cc th tch etanol v cht ch th ln hn i vi cc loi cht bo c mu m. Ngoi ra, i vi cc cht bo c mu m ny, cn s dng alkali blule hoc thymolphtalein.

Thm etanol trung ha vo phn mu th vo bnh cu th nht v trn k. un n si lng cha trong bnh v chun bng dung dch kali hydroxit hoc natri hydroxit, lc mnh bnh trong qu trnh chun .

f) Tnh kt qu

Tr s axit WAV c ghi li nh sau:- n hai ch s thp phn i vi cc gi tr t 0 n 1;- n mt ch s thp phn i vi cc gi tr t 1 n 100;- ly n s nguyn i vi cc gi tr > 100.

Tr s axit, WAV, c tnh theo cng thc sau:

Trong :c l nng ca dung dch chun natri hydroxit hoc kali hydroxit s dng, tnh bng mol trn lt (mol/l);V l th tch ca dung dch chun natri hydroxit hoc kali hydroxit s dng, tnh bng mililit (ml);m l khi lng phn mu th, tnh bng gam (g).

3.3.5.2. Xc nh ch s axit ca gi m theo tiu chun Codex 249-2006

Gi tr axit ca du t m n lin chin l s mg KOH cn thit trung ha 1 g du. Du chit xut t m c ha tan trong hn hp ru-ete v chun vi dung dch chun cn KOH.

a) Thit b

Bnh ht m kn kh: silica gel nhit 150C l tc nhn sy kh t yu cu.

b) Ha cht

- Dung dch chun cn kali hydroxit: 0,05 mol / L. Ho tan 3,5 g kali hydroxit trong th tch nc tng ng (khng cha CO2) v thm ethanol (95%) n 1 L. Sau khi trn, hy yn dung dch trong nhiu ngy gi dung dch khng cha CO2. S dng phn ni trn b mt dung dch sau khi tiu chun ha.

Tiu chun ha:

Cn s lng yu cu ca axit amidosulfuric v t n vo ht m (

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