polyphenol han che hien tuong cu

B CNG THNG

TRNG I HC CNG NGHIP TPHCM

VIN CNG NGH SINH HC THC PHM

BO CO N TT NGHIP

Tn ti

NG DNG POLYPHENOL T L I HN CH S

OXY HA SA BT CNG THC V BC U NG

DNG M HNH GIA TC SHELF-LIFE XC NH

THI HN S DNG SN PHM

GVHD: PHM MINH TUN & NG BI KHU

Lp i hc thc phm B

Nin kha: 2010 - 2014

Sinh vi n thc hin MSSV

1. TRNG HO I PHONG 10059631

2. C O N BO TRIT 10049151

3. L Q DI I N 10045841

4. NGUYN TH TNG VY 10061231

Thnh Ph H Ch Minh, Ngy 26, Thng 8, Nm 2014

Trng i hc Cng nghip Tp. HCM

VIN CNG NGH

SINH HC V THC PHM

CNG HA X HI CH NGH VIT NAM

c lp T do Hnh phc

NHIM V N TT NGHIP

VIN CNG NGH SINH HC V THC PHM

B MN: C S NGHNH

H V TN: TRNG HOI PHONG 10059631

CAO VN BO TRIT 10049151

L QU DIU VIN 10045841

NGUYN TH TNG VY 10061231

NGNH: CNG NGH THC PHM LP: HTP6B

1. u n: ng dng polyphenol t l i hn ch s oxy ha sa bt cng thc v

bc u ng dng m hnh gia tc shelf-life xc nh thi hn s dng sn phm

2. Nhim v (yu cu v ni dung v s liu ban u):

.

.............

.

.

3. Ngy giao nhim v lun n: .....

4. Ngy hon thnh nhi m v: ...

5. H tn ngi hng dn Phn hng dn:

1/

2/ .

Ni dung v yu cu LATN c thng qua B mn

Ngy . thng . Nm

CH NHIM B MN NGI HNG DN CHNH

(K v ghi r h tn) (K v ghi r h tn)

PHN DNH CHO VIN

Ngi duyt (chm h s): ...................................

n v: ..................................................................

Ngy bo v: .........................................................


VIN CNG NGH

SINH HC V THC PHM


c lp T do Hnh phc

Ngy . thng . nm ..

PHIU CHM BO V N TT NGHIP (Dnh cho ngi hng dn / phn bin)

1. H v tn SV: .

MSSV: Ngnh (chuyn ngnh):

2. ti: .

.

.

3. H tn ngi hng dn / phn bin: .

4. Tng qut v bn thuyt minh:

S trang: ... S chng: ...

S bng s liu: S hnh v:

S ti liu tham kho: ... Phn mm tnh ton: .

Hin vt (sn phm):

5. Tng qut v s bn v:

- S bn v: Bn A1: . Bn A2: . Kh khc: .

- S bn v tay: ...

6. Nhn xt: .

.

.

.

.

.

.

.

7. ngh: c bo v B sung thm bo v Khng c bo v

8. Cu hi SV phi tr li tr c Hi ng (CBPB ra t nht 02 cu):

a. .

.

b. .

.

c. .

.

nh gi chung (Bng ch: gii, kh, TB): im: ./10

K tn (ghi r h tn)


VIN CNG NGH

SINH HC V THC PHM


c lp T do Hnh phc

Ngy . thng . nm ..

PHIU CHM BO V N TT NGHIP

1. H v tn SV: .

MSSV: .. L p (ngnh): ...................

2. ti: .

3. Phn nh gi v cho im ca UV hi ng (theo thang 10 im)

- Trnh by:

- Tr li cu hi: - Thi , cch ng x, bn lnh: - Tng cng: ...

- im trung bnh do 1 UVH cho:

K tn

NHN XT CA GING I N HNG DN

...........................................................................................................................................

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...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

Tp. HCM Ngy... thng... nm 2014

GVHD1 GVHD2

NHN XT CA GING VIN PHN BIN

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

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Tp. HCM Ngy... thng... nm 2014

GV Phn Bin

i

1. LI CM N

Pha sau s thnh cng no cng u gn lin vi s h tr, gip d t hay

nhiu, d trc tip hay gin tip ca nhiu ngi. Trong sut thi gian lm bo co

n, nhm chng em nhn c rt nhiu s quan tm, gip qu bu ca

qu thy c, bn b v c gia nh.

Vi lng bit n su sc, u tin nhm chng em xin gi li cm n qu thy

c vin cng ngh sinh hc v thc phm trng i Hc Cng Nghip TP.HCM,

tn tm gip , ging dy v truyn t nhiu kin thc qu gi cho chng em.

c bit, nhm chng em xin gi li cm n n ThS. ng Bi Khu v

ThS. Phm Minh Tun tn tnh hng dn, ng gp nhiu kin cho nhm

chng em qua tng bui thc hnh ti phng th nghi m, cng nh nhng bui ni

chuyn, tho lun trong sut qu trnh lm n. Mt ln na chng em xin gi li

cm n chn thnh n thy.

Do bc u lm th nghim, thi gian c phn hn ch v kin thc cn hn

hep, bi bo co ca chng em khng trnh khi nhng thiu st. Rt mong nhn

c nhng kin ng gp qu bu ca qu thy c bi bo co c hon

thin hn.

Sau cng, nhm xin knh chc qu thy c vin cng ngh sinh hc v thc

phm tht di do sc khe tip tc thc hin s mnh cao p ca mnh l

truyn t kin thc cho cc th h tip theo.

Chng em xin chn thnh cm n!

Tp.H Ch Minh, ngy 26 thng 8 nm 2014.

ii

2. TM TT

Nghin cu ny tp trung vo vic la chn hm lng dch chit b sung ph

hp tng shelf-life cho sn phm sa cng thc. Shelf-life ca sn phm c xc

nh da vo m hnh gia tc shelf-life, thng qua gi tr peroxide theo thi gian. ng

thi xc nh cc ch tiu ca dch sa trc sy phun (hm lng polyphenol tng,

hm lng flavonoid tng, kh nng chng oxy ha bng phng php DPPH v bng

kh st) v cc ch tiu ca bt thnh phm (tnh chy, tnh thm t, ha tan, g t

trng,hm lng bo t do, n nh h nh tng v hiu qu vi bao). Sau qu trnh

thc hin nghin cu, chng ti thu c kt qu sau:

i vi kho st hm lng dch chit b sung, kt qu thc nghim cho thy

shelf-life ca sn phm tt nht m bo khng gy nh hng nhiu n cc tnh

cht ca bt cng nh cm quan ca sn phm sa l 733 ngy i vi cng thc phi

trn CT2. C th cng thc phi trn tt nht l: 30% sa bt gy, 10% du nnh,

0.5% lecithin, 5.2% maltodextrin, 2% lactose, 0.3% dch chit l i v 52% nc. Hm

lng polyphenol tng v hot tnh chng oxy ha (IC50) cn li sau qu trnh sy phun

l 281.1 mgGAE/100g bt v 13.63 ppm.

Cc ch tiu cht lng ca bt sa CT2 gm: Hm lng protein l 13.9% hm

lng bo tng l 20.27%, hm lng flavonoid l 6.1 mgRE/100g bt, kh nng

chng oxy ha bng DPPH l 13.63 ppm, bng phng php kh st l 0.54 mg

VitaminC/l. nh gi cc tnh cht ca bt CT2 thu c nh sau: hiu qu vi bao

84.42%, n nh h nh tng 91.29%.

iii

3. MC LC

LI CM N ........................................................................................................... i

TM TT ................................................................................................................ii

MC LC .............................................................................................................. iii

DANH MC BNG ............................................................................................... vi

DANH MC HNH ...............................................................................................vii

DANH MC CC T VIT TT ..................................................................... viii

M U .................................................................................................................. 1

CHNG 1 TNG QUAN.................................................................................. 3

1.1. Tng quan v nguy n liu. ................................................................................. 3

1.1.1. Dch chit l i. ......................................................................................... 3

1.1.2. Sa bt gy. .............................................................................................. 6

1.1.3. Lipid. ......................................................................................................... 8

1.1.4. Maltodextrin. .......................................................................................... 10

1.1.5. Lactose. ................................................................................................... 11

1.1.6. Lecithin. .................................................................................................. 13

1.2. Tng quan v phng php gia tc shelf-life. .................................................. 14

1.2.1. C s l thuyt ........................................................................................ 14

1.2.2. Cc cng trnh nghin cu v ng dng. ................................................ 18

1.3. Tng quan v sa cng thc. ............................................................................ 19

CHNG 2. T LI PHNG PHP NGHI N CU .................... 24

2.1. Nguyn vt liu. ................................................................................................ 24

2.1.1. Nguyn liu............................................................................................. 24

2.1.2. Ha cht chnh. ....................................................................................... 26

2.2. Ni dung th nghim. ........................................................................................ 26

2.2.1. Quy trnh cng ngh. .............................................................................. 26

2.2.2. Quy trnh nghin cu. ............................................................................. 27

2.3. Phng php xc nh. ..................................................................................... 30

2.3.1. Xc nh m. ...................................................................................... 30

2.3.2. Xc nh hm lng tro .......................................................................... 30

2.3.3. Xc nh hm lng polyphenol tng. ................................................... 31

2.3.4. Xc nh hm lng flavonoid tng ....................................................... 32

iv

2.3.5. Xc nh hot tnh chng oxy ha bng phng php DPPH ................ 34

2.3.6. Phng php kh st. ............................................................................. 35

2.3.7. Xc nh acid trong sa .......................................................................... 36

2.3.8. Xc nh hm lng bo......................................................................... 36

2.3.9. Xc nh hm lng bo t do v hiu qu vi bao. ................................ 36

2.3.10. Xc nh tnh n nh h nh tng ....................................................... 37

2.3.11. Xc nh hm lng protein ................................................................... 38

2.3.12. Xc nh ha tan. ............................................................................... 39

2.3.13. Xc nh tnh chy ca bt ..................................................................... 39

2.3.14. Xc nh tnh thm t ca bt. ............................................................. 40

2.3.15. Xc nh t trng ca bt ....................................................................... 40

2.3.16. Xc nh peroxyde .................................................................................. 40

2.3.17. K thut knh hin vi in t qut .......................................................... 42

2.3.18. Phng php so mu Minolta ................................................................ 43

2.3.19. Phng php x l s liu. ..................................................................... 46

CHNG 3 KT QU V BN LUN ......................................................... 47

3.1. Kt qu nh gi lng polyphenol, kh nng chng oxy ha ca dch chit l

i trong dch sa trc sy phun v bt sau sy phun. .............................................. 47

3.1.1. Hm lng polyphenol tng (TPC) v flavonoid tng (TFC). .............. 47

3.1.2. Kh nng chng oxy ha bng phng php DPPH v phng php kh

st ............................................................................................................ 50

3.2. Kt qu v nh hng ca dch chit ti cc tnh cht ca sa bt. ................. 52

3.2.1. Ch tiu m v tro ca bt sa. ............................................................... 52

3.2.2. T trng khi. ......................................................................................... 54

3.2.3. Tnh chy ca bt ................................................................................... 55

3.2.4. ha tan trong nc. ........................................................................... 56

3.2.5. Tnh thm t. ........................................................................................ 57

3.2.6. Bo, hiu qu vi bao v n nh h nh tng. ...................................... 58

3.2.7. Hm lng protein. ................................................................................. 60

3.2.8. Hm lng acid trong sa. ..................................................................... 63

3.2.9. Kt qu chp SEM. ................................................................................. 64

3.2.10. So mu Minolta. ..................................................................................... 65

3.3. Kt qu v nh hng ca dch chit ti shelf life ca sa bt. ....................... 67

3.3.1. Kt qu xc nh preroxyde theo ngy. .................................................. 68

v

3.3.2. Kt qu xc nh hn s dng. ............................................................... 70

CHNG 4 KT LUN V KIN NGH ...................................................... 73

T I LI TH M KHO

PH LC

vi

4. D NH MC BNG

Bng 1.1: Thnh phn khi lng ca lecithin tinh luyn v cha tinh luyn .............. 13

Bng 1.2: Yu cu v lng vitanmin trong sa ............................................................ 23

Bng 1.3: Yu cu v lng khong trong sa .............................................................. 23

Bng 2.1: Cng thc phi trn cc mu sa .................................................................. 29

Bng 2.2: Kt qu nh gi kh nng chy ca bt ....................................................... 40

Bng 3.1: Kt qu hm lng polyphenol v flavonoid trc sau sy phun .............. 47

Bng 3.2: Hot tnh chng oxy ha DPPH v kh Fe ca cc mu sa bt .................. 51

Bng 3.3: Ch tiu m v tro ca sa bt c b sung t l dch chit khc nhau ........... 52

Bng 3.4: Kt qu g t trng ca sa bt c b sung t l dch chit khc nhau ........ 54

Bng 3.5: Kt qu gc chy ca sa bt c b sung t l dch chit khc nhau ............ 55

Bng 3.6: ha tan ca sa bt c b sung t l dch chit khc nhau ...................... 56

Bng 3.7: Kt qu bo tng, hiu qu vi bao v n nh h nh tng ......................... 58

Bng 3.8: Kt qu hm lng protein ............................................................................ 61

Bng 3.9: Kt qu th hin s thay i acid sa ............................................................ 63

Bng 3.10: Th hin s thay i mu sc ca mu bt qua cc gi tr .......................... 66

Bng 3.11: S thay i ch s peroxyde ca cc mu trong thi gian bo qun ........... 68

Bng 3.12: Th hin nng lng hot ha, hn s dng, gi tr PV ti im kt thc, tc

i ha...................................................................................................... 71

vii

5. D NH MC HNH

Hnh 1.1: Cu to mt micelle casein .............................................................................. 7

Hnh 1.2: S ca d liu ngoi suy trong tng tc kim tra thi hn s dng. ......... 16

Hnh 1.3: th ca k so vi T ...................................................................................... 17

Hnh 1.4: th ng thng lnk vi 1/T ..................................................................... 18

Hnh 1.5: Quy trnh tm tt sn xut sa bt cng thc ................................................ 21

Hnh 2.1: S tm tt quy trnh th nghim ................................................................ 26

Hnh 2.2: Mt s cu trc c kh nng to phc kim loi ............................................. 32

Hnh 2.3: Phn ng chuyn DPPH (gc t do) sang DPPH (lin kt) ........................... 34

Hnh 3.1. Kt qu hm lng polyphenol v flavonoid trc sau sy phun .............. 48

Hnh 3.2: Biu th hin t trng khi c b sung t l dch chit khc nhau ........... 55

Hnh 3.3: Kt qu bo tng, hiu qu vi bao v n nh h nh tng ......................... 58

Hnh 3.4: Hm lng protein trc v sau sy phun ..................................................... 61

Hnh 3.5: Kt qu chp SEM ......................................................................................... 64

Hnh 3.6: th s thay i ch s peroxyde ca cc mu trong thi gian bo qun ... 69

Hnh 3.7: th th hin hn s dng ca cc mu ...................................................... 71

viii

6. D NH MC CC T IT TT

ASLT(Accelerated shelf life testing) : Gia tc tc shelf life.

TPC (Total polyphenol content) : Polyphenol tng.

TFC (Total flavonoid content) : Flavonoid tng.

PV (peroxyde value) : Gi tr peroxyde.

SMP (Skim milk powder) : Sa bt gy

DE : Dextroza Equivalent

SEM : Scanning electron microscopy

TNHH : Trch nhim hu hn

GVHD: Ths. Phm Minh Tun & Ths. ng Bi Khu n Tt Nghip

1

7. M

Nhu cu s dng thc phm ngy cng tng cao cng vi cc yu cu v cht

lng thc phm cng tng l n. Mt trong nhng nhu cu l hn ch qu trnh oxy

ha trong ch bin v bo qun thc phm. Trong s cc cht chng oxy ha,

polyphenol c xem nh l hp cht y tim nng c kh nng bo qun, chng oxi

ha cao v tt cho sc khe khi b sung vo thc phm. Theo cc nghin cu hin nay,

l i l ngun nguyn liu t nhin giu polyphenol gm: flavonoids, quercetins,

myricetin, catechin, tannin, acid ellagic (Chang CH, 2012). Do , dch chit xut t

l i l mt ngun cht chng oxy ha t nhin tim nng (Martha v cng s, 2008).

Bn cnh , iu kin kh hu v th nhng ca Vit Nam thch hp cho cy i pht

trin, vic nghin cu ng dng l i m ra mt hng mi va tn dng c ngun

nguyn liu l i di do, va thay th cc cht chng oxy ha tng hp bng hp cht

t nhin.

Sa c tc pht trin nhanh nht trong ngnh nng nghip, trong sn

phm sa bt c tim nng rt ln. Nm 2013, sn lng sa bt t 70.000 tn, tng

ng 28.000 t ng v s tng l n mc 90.000 tn (tng ng 48.000 t ng) vo

nm 2017. Sa bt cng thc cn t c nhng khuyn ngh dinh dng ca y ban

tiu chun ha thc phm quc t (CODEX). p ng khuyn ngh ca CODEX

hm lng bo cn t 3.0- 6.0 g/100 calories (Codex Stan 156-1987) v b sung cc

vi lng nh magie, st, km, cho dng sn phm ny. Hm lng bo cao v s c

mt ca cc kim loi trn dn n vic tng nhanh qu trnh oxy ha cht bo (Behrooz

Jannat, 2008), tng gi tr peroxyde cng nh qu trnh to nn cc hp cht gy mi

c cho sa nh 4-hydroxy-2,5-dimethyl-3(2H)-furanone, furfural v o-

aminoacetophenone (Stacy L. Schwambach, 2006). V vy, vic hnh thnh thm

peroxyde v cu t hng khng mong mun hu nh khng th ngn chn c nu

khng s dng cht chng oxy ha. Polyphenol c s dng ngn chn qu trnh

oxy ha c nghin cu bi rt nhiu tc gi trn rt nhiu sn phm: sa u


2

nnh-tr ln men (Danyue Zhao, 2014), tht b ming (Sancho Banon, 2007), du u

nnh (Ricardo Malheiro, 2013) v u cho kt qu tt.

C nhiu m hnh nh gi shelf life cho thc phm, trong m hnh gia

tc shelf life Arrhenius c ng dng rng ri. M hnh ny c ng dng thnh

cng cho cc sn phm nh mt to (Manuel Angel Palazn, 2008), sa tit trng t

bo UHT (Melanie Richards v cng s, 2014). rt ngn v tit kim thi gian v

c nh gi ng n v mt khoa hc i vi shelf life. V vy, nhm nh gi hiu

qu, tc ng ca polyphenol trong dch chit l i ti sn phm sa ny bng m hnh

gia tc shelf life.


3

1. CHNG 1 TNG QUAN

1.1. Tng quan v nguyn liu

1.1.1. Dch chit l i

i vi dch chit l i th ngun nguyn liu chnh sn xut dch chit l l i.

hiu su v r hn v dch chit ta i tm hiu tng quan v l i, tnh trng ngun

nguyn liu v quan trng hn chnh l cc hp cht m n cha. bit c l do ti

sao dch chit l i li c kh nng bo qun th ta cn tm hiu cc hp cht c trong l

i v cng dng ca nhng hp cht ny.

1.1.1.1. Thnh phn ha hc ca l i (Martha v cng s, 2008)

L i chim hm lng ln polyphenol nh flavonoid, tannin (Adeyemi,

2009).Trong l trng thnh, hm lng flavonoid ln nht c tm thy vo thng

By: myricetin (208.44 mg kg1

), quercetin (2883.08 mg kg1

), luteolin (51.22 mg

kg1

) v kaempferol (97.25 mg kg1

). L cha tinh du vi thnh phn chnh l -

Pinen, -Pinen, limonene, tinh du bc h, acetate terpenyl, isopropyl alcohol,

longicyclene, caryophyllene, -bisabolene, cineol, caryophyllene oxide, -copanene,

farnesene, selinene, cardinene v curcumene (Anil Kumar, 2012). Flavonoid v saponin

kt hp vi acid oleanolic c tch t l. Ngoi ra, l cha acid triterpenic, avicularin

v 3-l-4-pyranoside vi kh nng khng khun mnh, 6% tinh du, 3.15% nha, 8.5%

tanin v mt s cht khc nh cellulose, cht dip lc v mui khong.

1.1.1.2. Tng quan v cc hp cht phenolic

Polyphenol l nhng hp cht m trong cu trc phn t ca n c t nht

mt vng thm cng vi mt hoc nhiu nhm hydroxyl. Trn th gii hin nay, c

hn 8000 cu trc hp cht phenolic c bit n, v trong s c hn 4000 hp

cht thuc nhm flavonoid c xc nh. S phn b rng ri ca polyphenol

trong thc vt dn ti nhiu cch phn loi khc nhau. y chng ti chn cch

phn loi theo tc gi (Rong Tsao, 2010). Tc gi chia cc hp cht polyphenol

thnh hai nhm ln v nhiu nhm ph.


4

- Nhng hp cht phenolic khng phi Flavonoid.

- Hp cht flavonoid.

- Flavanol v proanthocyanidin.

- Flavone, Flavanone v Flavanonol.

- Anthocyanidin.

1.1.1.3. Cng dng v chc nng (Martha v cng s, 2008)

i l mt loi nng sn quan trng, dng lm cy thuc cc nc nhit i v

cn nhit i, c s dng rng ri nh thc phm v ph bin trong y hc dn gian

trn th gii. Nhiu th nghim dc l khc nhau c thc hin v xc nh c

cc thnh phn tho dc quan trng. Mt s cht chuyn ha cho hm lng cao v

mt s c chng minh c hot tnh sinh hc c ch ch yu thuc nhm phenolic,

flavonoid, carotenoid, terpenoid v triterpene.

Cc nghin cu gn y cho thy i c s dng nhiu ni tr n th gii

iu tr mt s bnh, v d nh thuc chng vim, bnh tiu ng, cao huyt p, su

rng, cha tr vt thng, gim au v gim st. Mt s cc quc gia c mt lch s lu

di trong vic s dng i lm thuc c truyn trong c Mexico v cc nc Trung

M bao gm c vng bin Caribbean, Chu Phi v Chu .

L v cnh c s dng Ty n trong gii nhit v chng co tht; bt t l

cy c s dng trong iu tr bnh thp khp, bnh ng kinh v bnh t v cn

thuc t l i dng cho tr em khi b co git.

Vic s dng cy thuc Trung Quc l mt thc t t lu i v vn cn ph

bin. L cy i l mt v d thng c s dng nh mt loi thuc ph bin cho

bnh tiu chy cng nh c xem l mt cht st khun.

Brazil qu v l c dng cho chng bing n, ti u chy, ri lon tiu ha,

kit l, suy d dy, nim mc b vim, vim thanh qun, ming (sng), vn v da,

au hng, vim lot. Ti M chit xut t l i c s dng trong cc cng thc tho


5

dc khc nhau cho v s cc mc ch, t cht khng sinh tho dc v tr tiu chy,

bo v ng rut v cn c tc dng gim cn.

Cht chng oxy ha, chng cc gc t do v kh nng chng phng x

Tn thng hoc tn hi n t bo trong qu trnh oxy ha pht sinh t cc gc

t do hoc oxy phn ng (ROS) dng nh l c ch c bn ca mt s ri lon thoi

ha thn kinh ca con ngi, bnh tiu ng, vim, nhim khun, bnh l t min

dch v ri lon h tiu ha. Nhng cht chng oxy ha c li n quan n cc hp cht

phenolic nh acid protocatechuic, acid ferulic, quercetin v guavin B, quercetin, acid

ascorbic, acid galic v acid caffeic. Chit xut t l i l mt ngun tim nng ca cht

chng oxy ha t nhin.

Khng sinh

Tc dng c ch ca cc dung dch chit xut t cn ca i (gc v l) trong s

pht trin ca Staphylococcus aureus, Streptococcus mutans, Pseudomonas

aeruginosa, vi khun Salmonella enteritidis, Bacillus cereus, Proteus spp, Shigellaspp

v Escherichia coli, tc nhn gy nhim trng ng rut ngi c nghin cu

trong ng nghim tr n mi trng thch (agar).

Trong mt nghin cu khc, n c quan st thy rng methanol t qu chn

c hot ng chng li nm Arthrinium sacchari M001 v chng Chaetomium funicola

M002. Chit xut dung dch methanol t l l cht c ch hiu qu s hnh thnh, pht

trin bo t v sn sinh c t ca Clostridium perfringens loi A.

Chng tiu chy

Chit xut ethanol v cc dung mi khc t l i nng 80 g/ml c kh nng

c ch hn 70% acetylcholine nguy n nhn gy ra cc cn co tht trong hi trng b

c lp. Hot tnh antidiarrhoeal ca cc chit xut c th l do c ch s tng dch tit

th lng thng xy ra trong tt c cc bnh tiu chy cp v dch t.

Quercetin cho thy hot tnh chng tiu chy ng k trong s co bp ca hi

trng chut lang trong th nghim v chuyn ng nhu ng trong rut non ca chut

v lm gim tnh thm thu ca mao mch bng. Galactose lectin lin kt vi


6

Escherichia coli, ngn nga s bm dnh vo thnh rut v do ngn nga bnh tiu

chy.

Tc dng chng ung th

Chit xut dung dch t l ca i c ch cc dng t bo ung th DU-145 theo

tng mc ph thuc vo liu dng. Tinh du chit xut t l i c hiu qu cao

trong vic lm gim s pht trin ca ung th biu b m ming ngi (KB)v bnh

bch cu chut (P388) c iu tr vi nng khc nhau t 0,019 mg/ml n

4,962 mg/ml. Tinh du l i cho thy cc hot ng khng sinh cao nht vi gi tr IC50

0,0379 mg/ml (mnh hn gp bn ln vincristine) trn dng t bo P388.

1.1.2. Sa bt gy

Sa bt gy c sn xut t sa ti ly tm tch bo. Sa bt gy c hm

lng cht bo (di 1,5% theo TCVN 7404 - 2004) v m thp.

Thnh phn ha hc

Trong sa, protein l thnh phn ch yu v casein l nhm protein ch yu trong

sa. Trong sa b casein chim gn 80% tng s protein hay khong 26 g cho 1 lt sa.

Casein c chia lm bn nhm ph -, s2 -, - v -casein. C bn nhm

ny u rt khng ng nht v c cha t 2 8 cc bin th gen khc nhau. Nhng

bin th ny khc nhau ch bi mt s t acid amin. im chung gia casein - v l

cc acid amin c este ha thnh acid phosphoric. Acid phosphoric ny lin kt vi

canxi (c cha nhiu trong sa) hnh thnh cc lin kt ni phn t v ngoi phn

t. iu ny khin casein d dng to chui polymer c cha mt vi loi casein ging

hay khc nhau.

Do c nhiu nhm phosphate v nhng nhm k nc trong phn t casein, cc

phn t polyme c hnh thnh t casein rt c bit v bn. Nhng phn t ny c

cu to t hng trm v hng nghn nhng phn t n l v hnh thnh nn dung dch

keo, to nn mu trng ca sa. Nhng phc cht ny c gi l cc micelle casein.

Hnh b n di cho thy cc micelle casein bao gm mt phc hp cc micelle, c


7

ng knh t 10 n 15 nm. Mt micelle vi kch thc trung bnh c ti 400 n 500

di-micelle v c th c kch thc ln ti 0.4 micron (0.0004 mm).

Hnh 1.1: Cu to mt micelle casein

Ch thch: A: di-micelle; B : chui b mt; C: Phosphat canxi; D: -casein; E:

nhm phosphat

Phosphat canxi v tng tc k nc gia cc di-micelle m bo cho tnh

bn vng ca cu trc micelle casein. Phn a nc ca -casein c cha nhm

carbohydrate, nhm ny nh bn ngoi ca cc micelle phc hp (B trong hnh 1.1),

to nn mt lp tc, nhng quan trng hn l chng gip cc micelle bn vng,

chng li s kt t.

Cng dng v chc nng

Sa gy l thc phm c gi tr dinh dng cao v hon ho, gm cht m, cc

vitamin v khong cht, nht l canxi sa. c bit, protein ca sa c gi tr sinh hc

cao nh vo hm lng l tng ca cc acid amin thit yu (proline, leucine, lysine,

valines, tyrosine, phenylalanine, glutamic acid) v c c th hp thu ton b.

Casein cung cp cc acid amin, canxi, protein casein c c tnh vn cc nn gii

phng acid amin cho c th chm n n trnh c s tiu hu c gi cho nng

acid amin trong mu n nh khi xa ba n, m bo vic cung cp nitrogen n nh

cho c th.


8

i vi sn phm sa cng thc dnh cho tr em, sa bt gy ng vai tr cung cp

protein m bo y dng cht cho s pht trin ca tr.

Cc hin tng h hng

Cht bo v protein sa b thay i ha hc trong qu trnh bo qun. Nhng

thay i ny c 2 dng: s i ha v s phn gii lipit. Sn phm to nn c mi kh

chu v thng xy ra i vi b sa v b.

S i ha cht bo: xy ra ti cc ni i ca cc acid bo khng no to nn mi

kim loi, trong lecithin l cht d tn cng nht.

S i ha protein: do s i ha amino acid di tc dng ca nh sng gy ra

mi kh chu. Ch mt vi pht di nh sng cng gy ra phn ng ny, do

sa khng n n trc tip di nh sng.

S phn gii lipit: l s phn ct cht bo thnh glycerol v acid bo, to mi v

chua, mi ny gy ra bi s hin din ca cc acid bo t do thp phn t. S phn ct

ny to ra di tc dng ca enzym lipaza. Tuy nhin qu trnh ny khng xy ra cho

n khi lp mng ca ht bo b ph hy v cht bo b l ra. Trong cng ngh sa s

ph hy mng rt d xy ra di tc dng c hc nh: bm, khuy, nh, ... trnh

xy ra qu trnh ny sa n n c thnh trng nhit cao phn hy enzyme

lipaza.

S xut hin ca cc mi v cng c th l mt du hiu ca s h hng, s pht

trin ca vi khun hoc s nhim bn. Sa bt n n c bo qun ni kh sch.Cn

phi trnh cc tc nhn lin quan ti s h hng ca thc phm, cc vt liu khc c

th b mc hoc l mi trng cho nm mc pht trin. Sa bt mt khi xut hin cc

mi l th khng nn s dng. Ngoi ra cn hng v do phn ng Maillard hay cn gi

l "caramel" hoc "mi nu".

1.1.3. Lipid

Lipit l nhng este phc tp c trong t bo sng, khng ha tan trong nc

nhng tan trong nhiu dung mi hu c khng phn cc.


9

Phn lo i cht bo

Cht bo c th phn thnh hai nhm ch yu l cht bo no v cht bo khng

no.Trong , dng khng no chim u th. Cht bo no rt n nh v bn thn n

khng cha cc lin kt i gia cc nguyn t carbon trong chui. Cht bo khng no

(c lin kt i) thng khng bn v rt d b i ha. Nhng lin kt i d b mt i

nht trong cc acid bo v c th d dng b tn cng bi oxy, hydro v cc enzyme.

Vai tr ca cht bo trong sa

Cht bo cung cp nng lng cho c th v cn thit cho vic hp th mt vi

loi vitamin. Nu n nhiu cht bo hn nhu cu, n s tch t trong m m di dng

d tr nng lng. Cht bo cung cp nng lng hn gp i so vi carbohydrate v

protein.

Cht bo l dung mi vn chuyn cc vitamin tan trong du m (nh vitamin A,

D, E v K). Cc vitamin ny i vo c th ph thuc vo hm lng cht bo trong

thc phm.

Cht bo t du thc vt cung cp nhiu acid bo cho c th. Hu ht cc acid

bo m c th cn c th t tng hp c trong c th nhng hai acid bo khng no

chui di (omega-3 v omega-6) c th khng th t sn xut m phi c cung cp

thng qua ch n hng ngy. Chc nng ca chng trong c th con ngi l gi

nc di da, trnh mt nc v duy tr chc nng truyn tn hiu ca h thn kinh.

Cholesterol trong c th con ngi cn cho qu trnh sn xut hc mn v cho

mng t bo. N c tng hp t c th v c cung cp t thc n b n ngoi. C

th s iu chnh s tng hp cholesterol da vo lng cholesterol n hng ngy.

Cholesterol v vi sterol thc vt hin din trong cht bo sa trong dinh dng c th

ng vai tr tch cc trong s tng trng v pht trin ca tr, mt s nh sn xut

a cholesterol vo sa cng thc cho thai nhi.

Cc hin tng h hng

Cht bo b oxy ha thnh hydroperoxides lipid (sn phm oxy ha chnh)

thng qua mt qu trnh ca gc t do, sau phn hy v gy ra qu trnh oxy ha cc

sn phm th cp, chng hn nh cc hp cht cacbonyl, andehit, xeton, hydrocarbon


10

v ru. Hydroperoxides lipid khng c v v khng mi, trong khi cc sn phm oxy

ha th cp l cc phn t khng n nh to ra cc mi v hng v l kt hp vi s

oxy ha v i ha , hnh thnh cc hp cht c hi v lm gim gi tr dinh dng v

cht lng thc phm (Sandra P. O' Dwyer, 2013).

1.1.4. Maltodextrin

Maltodextrin c ng dng rng ri trong nhiu lnh vc ch bin thc phm

v dc phm. Theo dc in M USP 24, maltodextrin l mt cht khng ngt, l

sn phm thy phn tinh bt khng tan hon ton bng acid hoc bng enzyme hoc

bng acid v enzyme hn hp cc polymer c n v l D-glucoza c ng lng

dextroza DE di 20. Mc trng hp (DP) th hin t l phn trm lng glucose

c bin i ca tinh bt. ng lng Dextroza Equivalent vit tt l DE l i

lng ch kh nng kh i vi ng chun l 100% ng glucoza (dextrose), hay

l s gam tng ng D-glucoza trong 100 gam cht kh ca sn phm, t l nghch

vi kch thc phn t. Maltodextrin c s dng rt nhiu trong ngnh cng nghip

thc phm v giy. Trong ngnh cng nghip thc phm ty theo gi tr DE khc nhau

nn s c la chn khc nhau v khu v, kh nng ha tan, nh hng n nht

v chc nng "cht mang 'cho cc hng v khc nhau cho thc phm. Gi tr DE thp

th th hin chc nng l cht mang tt hn tuy nhi n n t ha tan. Ngc li gi tr

DE cao hn th kh nng mang thp b vo kh nng ha tan tt hn v to hng

tt hn.

Phn lo i maltodextrin

Sn phm c DE t 4 -7 c s dng to mng mng d tan v t hy c

dng bc ko, bc tri cy khi bo qun, a vo kem, lm ph gia cho cc loi

nc xt, lm cht n to vin trong cng nghip dc.

Sn phm c DE t 9-12 c dng trong cng nghip sn xut ung, c

bit l ung cho tr em, ung v thc n ri ng cho vn ng vin th thao, lm

ko gum mm, lm cht tr sy, cht gi hng, yu t to hnh.


11

Sn phm c DE t 15-18 c lmcht kt dnh, cht tng v cho ung, a

vo thnh phn b, sa bt, c ph ha tan, lm vt mang cc thnh phn khng phi

ng, lm t dc dnh trong cng ngh dc phm (Trng Th Minh Hnh, 2008).

Vai tr ca maltodextrin i vi sa bt

Trong cng ngh sn xut sa bt, maltodextrin c xem l mt cht mang

quan trng trong vic gim gi thnh sn phm, nng cao hiu qu qu trnh sy phun.

Khi so snh gia sn phm sa bt gy v maltodextrin, tc gi Ozmen v Langrish

nhn thy rng mu sa bt gy ng u khp b mt ca hnh nn, trong khi

maltodextrin ch tp trung phn nh v y hnh nn. iu ny cho thy s dng

maltodextrin trong sy phun gip gim hin tng hao ht bt trn b mt bung sy

(Langrish, 2007). Ngoi ra, vic p dng maltodextrin trong sa bt c th loi b mi

l v n nh cht dinh dng v nng cao cht lng.

m ca sn phm bt gim khi hm lng maltodextrin cao Krishnaiah v

cng s (2012). iu ny cng c nhn thy trong nghin cu ca tc gi Silva v

cng s (2013), mu bt c 30% maltodextrin th c m l 4.84 1.19 (%), mu bt

c 25% arabic gum vi 5% maltodextrin th c m 6.76 0.34 (%). Cng theo

Krishnaiah v cng s (2012), trong h thng sy phun, hm lng nc trong nguyn

liu u vo cung cp cho thit b c nh hng n m cui ca sn phm. Vic b

sung maltodextrin cho nguyn liu u vo trc khi sy phun c hm lng cht

kh tng l n v gim hm lng nc c trong nguyn liu u vo thun li cho

qu trnh sy phun.

1.1.5. Lactose

Lactose l mt disaccharide c ngun gc t galactose v glucose, c tm

thy trong sa. Lactose chim khong 2 - 8% sa theo trng lng.

c im

Bt lactose c mu trng. C tan l 1/4.63, tc l 0.216 g lactose tan hon

ton trong 1 ml nc. Lactose ha tan trong dung dch c tm thy tn ti 2 dng


12

-anome v -anome, c th chuyn i qua li gia hai dng. ha tan ca 2 anome

ph thuc vo nhit v do nng cn bng ca 2 hnh thc s khc nhau nhit

khc nhau. nhit phng (70F, 20C) t l cn bng l khong 37% v 63% -

-lactose. nhit trn 200F (93.5C) -anome l t ha tan nn c mt t l cao

hn - -lactose. S c mt anome khng nh hng n tnh cht dinh dng ca

lactose.

Tinh th lactose hnh thnh khi nng lactose cao hn kh nng ha tan ca

chnh bn thn n (qu bo ha). Cc tnh cht vt l ca tinh th lactose ph thuc vo

loi tinh th v mi loi tinh th s c nhng cch s dng khc nhau trong thc phm.

Cc tinh th -lactose monohydrat c hnh thnh rt kh v khng ng nht v hnh

dng. Vic ny dn n hnh dng tinh th khng ng u, kt cu ct khng mong

mun trong tinh th. Khi lactose c sy kh qu nhanh chng v khng c thi gian

kt tinh kt qu l hnh thnh tinh th dng gng. S tn ti tinh th ny trong sa

bt gy hin tng vn cc gy nh hng khng tt ti ha tan ca bt sa.

Lactose khng ngt nh disaccharides khc nh sucrose, monosacarit fructose

hoc glucose. Lactose c phn tch thnh glucose v galactose trong rut ca tr s

sinh bi s phn gii ca lactase (hoc -galactosidase). Cc galactose sau c

chuyn i sang ng khc bng mt loi enzyme khc nhau.

Cng dng ca lactose

Lactose l mt loi ng c tm thy ch c trong sa. N thuc v nhm

hp cht ha hc hu c c gi l carbohydrate.Carbohydrates l ngun nng lng

quan trng nht trong n ki ng. C th chng ta ph v chng thnh cc hp cht nng

lng cao c th tham gia vo tt c cc phn ng sinh ha cung cp nng lng

cn thit. Carbohydrates cng cung cp nguyn liu cho qu trnh tng hp mt s hp

cht ha hc quan trng trong c th. Chng c mt c glycogen trong c bp v gan

di dng glycogen gan. Lactose thc hin chc nng sinh hc quan trng, trong

bao gm u s hp thu canxi, kch thch s tng trng ca bifidobacteria v cung cp


13

galactose, mt cht dinh dng cn thit cho s hnh thnh ca no (Maldonado,

1998).

Lactose l mt nguyn liu tiu ha d dng v l ngun cung cp nng lng

cho tr s sinh. Lactose l mt disaccharide, c ngha l n c to thnh t hai n

v ng nh hn l glucose v galactose, c hai u l ngun nng lng cho cc t

bo trong c th. Khi con ngi tiu th lactose, lactose b ph v thnh glucose v

galactose bng enzyme lactaseReginald Garrett v sau c th hp th cc loi

ng nh vo mu.Cc t bo phn hy glucose v galactose thnh carbon dioxide v

nc. Qu trnh ny to ra mt s lng ln ATP - ngun nng lng m cc t bo

s dng duy tr cho cc qu trnh, hot ng khc.

1.1.6. Lecithin

Lecithin l tn ph bin v thng mi cho mt hn hp t nhin ca

phosphatide (cn gi l phospholipid hay phosphoglycerides), mu sc thay i t

vng mu nu v c dng lng sn st. Lecithin tan tt trong du v cc dung

mi khng phn cc. Ga tr HLB = 3 4 (i vi lecithine phn cc thp), HLB = 10

12 (i vi lecithin hiu chnh).

Thnh phn ha hc

Bng 1.1: Thnh phn khi lng ca lecithin tinh luyn v cha tinh luyn

Hp cht Lecithin cha tinh

luyn (%)

Lecithin tinh luyn

(%)

Phosphatidyl choline 17.5 23

Phosphatidyl ethanolamine 15.0 20

Phosphatidyl inositol 10.0 14

Other phospholipids 14-18

Unrefined soy oil 31-34 0-3

Glycolipids 13-16 13-16

Neutral lipids 2-4

Ngun: B.F. Szuhaj (1982), Central Soya Co., Inc. Lecithin Div. Fort Wayne, Indiana.

Personal communication.


14

Cng dng v chc nng

Lecithin l thnh phn nh ha thng c s dng trong sn xut ung sa

da trn s ti kt hp nhit tit trng v d nh sa cng thc cho tr s sinh. Trong

sa cng thc cho tr s sinh tui u ti n thng thng, chi phi bi cc quy nh ca

EU v Codex, y l nhng cht nh ho c cho php (Codex Alimentarius

Commission, 1981; y ban ca Cng ng Chu u, 1991). Mc ch chnh ca vic

a cc ph gia thc phm l h tr trong qu trnh nh tng ha. L mt cht c

trng lng phn t thp b mt chng di chuyn nhanh chng n b mt ca git

cht bo nh c hnh thnh trong qu trnh ng ho v cng vi cc protein sa to

thnh mt mng bao quanh cc git nh, do ngn nga s hp nht v keo t (S.L.

McSweeney v cng s, 2008).

Phosphatidylcholine l mt trong nhng thnh phn ca lecithin c mt t l

phn trm cao ca chui acid bo khng bo ha, acid linoleic 70% v acid linolenic

6%, m chu u c gi l vitamin F. Vitamin F c tm thy l rt quan trng

chuyn ha cht bo v gii phng cc cht bo t m m .

1.2. Tng quan v phng php gia tc shelf-life

1.2.1. C s l thuyt

Ngi ti u dng ngy cng i hi cao v cht lng thc phm v m bo

cht lng lun lun tt trong thi gian bo quan t lc bn n khi ngi tiu dng s

dng. Do , ngnh cng nghip thc phm quan tm nhiu ti vic c thng tin cn

thit xc nh tui th ca sn phm trong mt thi gian ngn. Thng tin ny tc

ng ti vic x l, lu tr, phn phi v thi hn s dng ca sn phm.

Nhn chung, nhng thay i v vi sinh, ha hc, cm quan c vai tr quyt nh

cho dng i sn phm. C ba s thay i trn c th xc nh dng i trung bnh ca

sn phm (McGinn, 1982).

Theo IFST (1993) cung cp mt nh ngha hon ton kh thi v hn s dng.

Hn dng c nh ngha l thi gian trong cc sn phm thc phm s:


15

- Vn an ton.

- m bo gi li cm quan, tnh cht, c tnh vt l v vi sinh mong mun.

- Tun th theo cc quy nh v cc thng s dinh dng tr n nhn khi c

lu tr trong cc iu kin khuyn ngh.

S tng tc ca cc yu t b n trong v b n ngoi nh th no hoc l c ch

hoc kch thch nhng bin i nh hng ti hn s dng. C th phn loi cc yu t

nh sau: Vi sinh, ha hc, vt l, nhit .

V l do thc t, c bit l khi sn phm c thi gian s dng thc t qu di,

cc cng ty s dng gia tc shelf life rt ngn qu trnh thu thp d liu thc

nghim cn thit ng k. Do , gia tc tc shelf life (ASLT) c kh nng nh gi s

n nh sn phm da trn d liu thu c trong mt thi gian ngn hn ng k so

vi thi gian tin hnh trong mi trng thc t ca sn phm.

ASLT c p dng cho bt k qu trnh h hng no c m hnh ng hc

thch hp. Qu trnh c th l ha hc, vt l, sinh ha hay vi sinh. Nguyn tc ca

ASLT s ging nhau trong mi trng hp.

Cch tip cn m hnh ng hc l phng php ph bin nht tng tc kim

tra thi hn s dng. Qu trnh c bn bao gm cc bc sau:

- La chn cc mong mun cc yu t ng hc tch cc cho kh nng tng tc

ca qu trnh h hng.

- Chy mt nghin cu ng hc ca qu trnh h hng mc nh vy ca

y mnh yu t t l h hng l nhanh.

- Bng cch nh gi cc thng s ca m hnh ng hc, ngoi suy d liu iu

kin bo qun bnh thng

- S dng cc d liu ngoi suy hoc m hnh ng d on thi gian s dng

iu kin thc t.


16

Hnh 1.2: S ca d liu ngoi suy trong tng tc kim tra thi hn s dng.

Gia tc shelf life

Khi p dng phng php m hnh ng hc, vic u tin cn xem xt l nh

gi da trn mt yu t hay nhiu yu t thc y phn ng h hng. Cch n gin

nht v hu ht thng c s dng l phng php gia tc shelf life (ASLT) da trn

s dng mt yu t duy nht y nhanh qu trnh h hng. Phng php ny n

gin tin trnh th nghim v php ni suy kt qu.

Nh nu, shelf life cn c m hnh ng hc ph hp. iu quan trng l

trong ASLT, s ph hp ca m hnh ng hc t c kt qu chnh xc v hn

s dng. V vy, vic la chn mt m hnh cho ASLT phi cn c vo nn tng thc

t ca n. Sau ny c th da trn d liu thc nghim.

M hnh Arrhenius cho thy t l phn ng ha hc vi nhng thay i v nhit

l v d tt nht ca mt m hnh xc nhn nh vy. M hnh ny c i din bi:

Phng trnh Arrhenius:


17

Trong :

K: Hng s tc A: H s tn s.

Ea: Nng lng hot ha(kJ/mol). R: Hng s gas (8.314 J/molK)

T : Nhit Kelvin.

T khi c m hnh ny th c s dng trong nhiu trng hp khc nhau. Mt

c s d liu c sn ln hnh thnh, ch yu l nng lng hot ha cho cc phn ng

khc nhau. Tnh tin li y l c th s dng thng tin ny c tnh gn ng

mc nh hng ca thay i nhit n tc phn ng.

V mt ton hc, tng nng lng hot ha tc phn ng gim v khi nhit

tng tc phn ng tng.

Theo nghin cu th ca K so vi T l mt ng cong.

Hnh 1.3: th ca k so vi T

Tuy nhi n, th ca lnK vi 1/T l mt ng thng

Ly logarit ca phng trnh Arrhenius c:

a v dng: y = mx + b


18

Trong : y = lnk, m =

, x =

, b = lnA

Ta v li c th sau:

Hnh 1.4: th ng thng lnk vi 1/T

dc ca ng thng =

V vy, Ea = - ( dc) x R

1.2.2. Cc cng trnh nghin cu v ng dng

Vi nhu cu thc t hin nay, hn s dng l thng s rt quan trng v c

nhiu ngi quan tm. V vy rt nhiu nghin cu ng dng gia tc shelf life cho cc

sn phm.

Mt tp ch tin hnh shelf life trn mu thc phm v a ra nhng con s

chnh xc ti khi mt mu l 7 thng 20C v 8 tun 30C v 40C khi s dng

nhn t nhit kt hp vi nh sng mnh (Leatherhead Food Research relies on

KBF P).

Mt nghin cu khc v nh gi sn phm ca h. Nhm nghin cu ny tin

hnh xc nh hn s dng da vo cc tnh cht nh i, mu nu nonenzymatic, lng

vitamin C v nh gi cm quan v kt qu cho thy rng m hnh Arrhenius c log t

l vi nhit Kenvil (P Labuza, 2003).


19

Mt chng minh khc v chnh xc ca gia tc shelf life ph thuc vo m

hnh l tui th ca mt hng bt d on da trn m hnh Guggenheim-Anderson-

Deboer v mi quan h m th kt qu tnh ton cho ra c hn s dng c l

114.68 ngy v kt qu thc t cng khng chnh lch nhiu so vi d on ca m

hnh c thi hn s dng l 105 ngy (S. Jaya v H. Das, 2005).

1.3. Tng quan v sa cng thc

Sa m l thc n tt nht cho tr s sinh cho con b, cho li ch dinh dng v

trao i cht ca tr, nh hng tm l v vai tr trong vic ngn nga bnh tt. Khi

khng th cho con b, sa m phi c thay th bng mt cng thc cho tr s sinh

p ng cc nhu cu dinh dng ca tr. Ngy nay, cc chuy n gia dinh dng c th

chn t mt lot cc cng thc cho tr s sinh c bit s dng phng nga hoc

iu tr. T mt hoc nhiu thnh phn c loi b, sa i hoc thay th

(Maldonado, 1998).

Quy trnh sn xut (Hnh 1.5)

u tin l nguyn liu. Nguyn liu sn xut sa bt l sa ti nguy n kem

hoc sa gy. Sa nguyn kem l sn phm c ch bin t sa ti khng hiu chnh

hm lng cht bo. Sa gy l sn phm c ch bin t sa ti c tch bt mt

phn cht bo.

Ngoi nguyn liu chnh l sa ti hoc sa gy, ngi ta cn s dng mt s

ph gia trong sn xut sa bt nh cht n nh (polyphosphate, orthophosphate ca

Na, K, Ca) cht to nh lecithin, cht chng oxy ho...

Tip l qu trnh chun ho sa nhm hiu chnh hm lng cht bo trong

nguyn liu v b sung cc thnh phn dinh dng thit yu khc, c thc hin trn

dy chuyn t ng bao gm my ly tm, b phn phi trn, cc dng c o (lu lng

k, t trng k) bm vo thng cha.

Bc tip theo l thanh trng nhm lm gim s vi sinh vt trong sa n mc

thp nht, ng thi v hot cc enzym, c bit l nhm enzym bn nhit lipase, lm


20

thay i tnh cht ca protein. Thanh trng thng c thc hin nhit 80-850C

trong vi giy. Qu trnh thanh trng sa c thc hin trn thit b trao i nhit

dng bng mng.

Do hm lng cht bo trong sa sau qu trnh c c kh cao nn nh sn xut

thc hin qu trnh ng ho gim kch thc ht bo v phn b u chng trong

sa.

Tip theo l sy sa. Sn phm ch bin t sa c c n kh 35 - 40%,

em sy kh, nghin thnh bt, sng, ry c sa dng bt c kh 90 - 96%,

m 4 - 10%. Ty thuc vo thit b sy m ngi ta c c sn phm sa bt c cht

lng khc nhau. thu nhn sa bt, ngi ta c th thc hin cc phng php sy

khc nhau nh sy thng hoa, sy trc nhng hin nay, sy phun c s dng nhiu

hn c.

Sa bt sau khi sy phun s c mang i phi trn thm cc thnh phn vi

lng cn thit, ri c a qua h thng ry ri vo thit b ng gi. Thng thng

ngi ta s dng bao b bng kim loi hoc bao b giy ng sn phm.Yu cu

chung v bao b l phi hn ch s tip xc ca nh sng, khng kh v m t mi

trng xung quanh n sa bt. Ngi ta thng ng gi trong iu kin chn khng

hoc thi hn hp 90% nit, 10% hydro vo hp trc khi ghp np nhm ko di thi

gian bo qun ca sn phm. Sa bt c kh nng ht m rt cao do khi bo qun

trong bao b kn, sa bt s ht nc n m cn bng, to thnh cc cc vn lm

gim ho tan ca sa.


21

Hnh 1.5: Quy trnh tm tt sn xut sa bt cng thc

Tiu chun cht lng ca sa cng thc

Da theo tiu chun ca U ban tiu chun ha thc phm quc t CODEX,

CODEX STAN 156-1987.

Nng lng

Khi chun b ph hp vi hng dn s dng, 100 ml sn phm sn sng cho tiu th

s cung cp khng t hn 60 kcal (hoc 250 kJ) v khng qu 85 kcal (hoc 355 kJ).

Nguyn liu

Chun ha

Ha sa

Trn kh

Sy

ng ha

Thanh trng

Bao gi Bao b

Sa bt nguyn

kem


22

Thnh phn cht dinh dng

Protein

Khng t hn 3.0 g trn 100 calo c sn (hoc 0.7 g trn 100 calo c sn) ca

protein cht lng dinh dng tng ng vi casein hoc mt s lng ln cc

protein khc trong t l nghch vi cht lng dinh dng ca n. Cht lng ca

protein khng c thp hn 85% so vi casein. Tng lng protein khng c hn

5.5 g trn 100 calo c sn (hoc 1.3 g trn 100 calo c sn).

Axit amin thit yu c th c thm vo theo di cng thc duy nht nng

cao gi tr dinh dng ca n. Axit amin thit yu c th c th m vo ci thin

cht lng protein, ch vi s lng cn thit cho mc ch . Ch c dng L ca cc

axit amin c s dng.

Cht bo

Khng t hn 3 g v khng qu 6 g trn 100 calo (0.7 v 1.4 g trn 100 calo c

sn). Mc acid linoleic (trong dng glyxerit) khng c thp hn 300 mg mi 100

calo (hoc 71.7 mg mi 100 calo c sn).

Carbohydrates

Sn phm phi cha carbohydrate dinh dng c sn ph hp vi thc n ca

tr s sinh ln tui v tr nh vi s lng nh iu chnh sn phm mt nng

lng ph hp vi cc yu cu quy nh v nng lng.


23

Vitamins

Bng 1.2: Yu cu v lng vitanmin trong sa

S lng trn 100 calo c sn

Ti thiu Ti a

Vitamin A 250 I.U 750 I.U

Vitamin D 40 I.U 120 I.U

Vitamin C 8mg Khng quy nh

Vitamin B1 40g Khng quy nh


Nicotinamide 250g Khng quy nh


Vitamin 12 0.15g Khng quy nh

Vitamin K1 4g Khng quy nh

Vitamin H 1.5g Khng quy nh

Folic acid 4 g Khng quy nh

Pantothenic acid 300 g Khng quy nh

Khong cht

Bng 1.3: Yu cu v lng khong trong sa

S lng trn 100 calo c sn

Ti thiu Ti a

Natri 20mg 85mg

Kali 80mg Khng quy nh

Clo 55mg Khng quy nh

Canxi 90mg Khng quy nh

Photpho 60 Khng quy nh

Magie 6mg Khng quy nh

St 1mg 2mg

I t 5g Khng quy nh

Km 0.5mg Khng quy nh


24

2. CHNG 2. T LI PHNG PHP NGHI N CU

2.1. Nguyn vt liu

2.1.1. Nguyn liu

Nguyn liu chnh

Dch chit l i

L i non c hm lng polyphenol cao hn so vi l i trng thnh theo

nghin cu ca Nantitanon v cng s (2010). V th, nguyn liu chng ti chn l

l i non trch ly dch.

X Xun Thi ng, Hc Mn, H Ch Minh l ni chng ti chn thu hoch

l i non cc h gia nh. Tng l c hi mt cch cn thn bng tay, trnh dp

nt gy h hng. Sau , chng ti loi nhng l vng a, dp nt, gi ra khi

m bo rng nguyn liu c mang i s dng l l i non v c mu sc tng

ng vi nhau.

L sau khi c kim tra, lm sch th tin hnh chn sau nhit 1000C

trong vng 30 giy vi mc ch l v hot enzyme polyphenol-oxydase gim tn

tht lng polyphenol trong sut qu trnh sau. Sau , ngm trong nc lnh 50C

trong vng 30 pht n nh nhit trnh phn hy cc hp cht (Nantitanon v

cng s, 2010). Tip theo, mang mu chn i sy 500C trong 5 gi; ri cho vo

ci xay kh xay nh. Bt l kh sy c bo quan trong bao nilong ngn

mt t lnh vi iu kin nhit khong 40C, mu bt xay phi c kch thc ht

ng u, mn.

Qua qu trnh th nghim s b trch ly polyphenol t l i bng phng

php vi sng, chng ti nhn thy rng khi trch ly polyphenol t l i bng phng

php vi sng c hiu qu hn khi s dng phng php trch ly dung mi truyn

thng. iu kin trch ly tt nht i vi nguyn liu l i l: loi dung mi ethanol,

khi t l nguyn liu:dung mi l 1:25 (Pan, Niu v Liu, 2003), nng dung mi l

ethanol 50% (Li Th Ngc H, 2012), mc nng lng 385W (Song v cng s,

2011), thi gian trch ly l 13 pht (Tachkittirungrod v cng s, 2007). Dch thu

c ngay lp tc c lm mt v bo qun lnh phi vi sa theo cng thc.


25

Sa bt gy

Sa c mua ti ca hng Phng H (58 Hm Nghi, Qun 1, Tp.H Ch

Minh) c nhp khu t New Zealand. Sa c bc kn trong bao b giy nhm,

mi bao khi lng 500g. Tiu chun cht lng, tun theo TCVN 7404:2004.

Lipit

Du nnh c cung cp bi Cng Ty C Phn Du Thc Vt Tng An,

48/5 Phan Huy ch, phng 15, qun Tn Bnh, Tp. H Ch Minh. Sn phm c

ng trong chai nha dung tch 1 lt. Tiu chun cht lng, tun theo

8637/2012/YT-CNTC v TCCS02:2012/TA

Nguyn liu ph

Maltodextrin

Maltodextrin c cung cp bi cng ty TNHH Bch Khoa, Kios S 6 - 334

T Hin Thnh P.14, Q.10, Thnh ph H Ch Minh. Sn phm c ng trong

chai nha khi lng 500g. Mt s ch tiu cht lng ch yu: m 3.35 %, DE

10.

Lactose

Lactose c cung cp bi cng ty TNHH Bch Khoa, Kios S 6 - 334 T

Hin Thnh P.14, Q.10, Thnh ph H Ch Minh. Sn phm c ng trong h

nha khi lng 500g. Mt s tiu chun cht lng: tinh khit 99%, gc quay

cc +89.40, nhit nng chy 201.6

0C, tan trong nc 25

0C l 18.9 g/100ml

dung dch.

Lecithin u nnh

Lecithin c cung cp bi cng ty TNHH Bch Khoa, Kios S 6 - 334 T

Hin Thnh P.14, Q.10, Thnh ph H Ch Minh. Cc thng s ch tiu ch yu:

m 1%, ch s acid 30 (mg/KOH), ch s peroxyde 10 (meg/Kg), HLB 3-4, khng

tan trong hexan 0.5%.


26

2.1.2. Ha cht chnh

Rutin c mua ti Cng ty TNHH Ha Nam (239/4, L Thng Kit,

phng 15, qun 11, H Ch Minh). Xut x t n .

Folin-Ciocalteu c mua ti Cng ty TNHH Bch Khoa (332 T Hin

Thnh, 14, 10, H Ch Minh). Xut x t c.

DPPH (2,2-diphenyl-1-picryl-hydrazyl) c mua ti ca hng Vit Hong

Long (136 T Hin Thnh, phng 14, qun 10, H Ch Minh). Xut x t c.

2.2. Ni dung th nghim

2.2.1. Quy trnh cng ngh

Cc bc tin hnh cho ra sn phm bt sa c tin hnh theo quy trnh

sau:

Hnh 6.1: S tm tt quy trnh th nghim

Nguyn liu s dng l bt l i sau khi trn u v ry m bo s

ng u ca bt nguyn liu. Bt c cn khi lng chnh xc 10g v cho vo

bnh cu 2 lt, b sung dung mi ethanol 50% theo t l nguyn liu: dung mi l

1:25 m bo khng tht thot mu trn dng c cha mu bng cch trng ra

Nguyn liu

Phi trn

Sy phun

(200oC, 3atm)

ng ha

(200 Bar)

Thanh trng

(75C -20 giy)

Bt l i:cn

(1:25)

Trch ly bng vi sng

13 pht, 385W

Lc

C quay 15 pht, 45oC

Dch chit

Bt sa


27

dng c nhiu ln vi dung mi. Tip n mang i trch ly bng vi sng mc nng

lng 385W trong thi gian 13 pht. Ton b dch sau trch ly c mang lc qua

giy lc bng h thng lc chn khng. Dch thu c t qu trnh lc bao gm

dung mi v cc hp cht ha tan c em i c quay nhit 450C, trong thi

gian 15 pht nhm loi b dung mi. Ton b dch sau c quay c trn u v

gi trong chai ti mu, ngn mt ca t lnh.

Cng on phi trn nhm mc ch ha tan tt c cc thnh phn nguyn

liu thnh dch ng nht thun li cho cc qu trnh sau. Sa bt gy,

maltodextrin, lactose c trn cng vi nc trc, nhit ca nc khong 50-

600C, du nnh v lecithin c thm vo sau. Dch chit v FeSO4 c b sung

vo cui cng.

Sau khi phi trn, dch c mang i ng ha p sut 200 bar bng thit

b ng ha. Dch sau ng ha c thanh trng nhit 72 75C trong 15

20 giy (Tetra Pak Dairy Processing Handbook, 2003) v c gi li mt phn

kim tra cc ch ti u ha l: hm lng polyphenol tng, hm lng flavonoid, kh

nng chng oxy ha bng kh st v DPPH. Phn dch cn li c sy phun bng

thit b sy phun Lab Plant (Anh, SD-06AG) u phun kh nn vi cc thng s:

nhit u vo 200oC (Esther H.-J. Kim, 2008), nhit u ra 80

oC, p sut 3

bar, tc bm 695 ml/h.

2.2.2. Quy trnh nghin cu


28

Sa, maltodextrin,

lactose, du, lecithin.

Dch chit l i

Bt l i

Phi trn

Trch ly bng vi sng

Lc

C quay

Phi trn

ng ha

Sy phun

Bt sa

Hm lng Polyphenol

DPPH

Kh st

Hm lng Flavonoid

Shelf life

Kim tra cc ch

tiu ca dch sa

Cc tnh cht ca bt Kim tra cc ch tiu ca

dch sa hon nguyn

Hm

l

ng

Poly

phen

ol

Hm

l

ng

Flav

ono

id

Kh

st

DP

PH

Tn

h ch

y

Xc

nh P

erox

yd

Hn

s dn

g

Bo

Pro

tein

SE

M

Tn

h th

m

t

ha tan

T tr

ng

Thanh trng


29

Chng ti nghin cu giai on trn t nhm to ra sa nn vi hm lng

m, bo t yu cu khuyn ngh ca CODEX. Trong cng on ny, chng ti

kho st nhm a ra hm lng dch chit b sung ph hp bo qun v khng

nh hng ti cm quan cng nh cc tnh cht ca sa. Hm lng dch chit c

b sung vi t l cht kh dch chit so vi tng dch sa ln lt l 0.2%, 0.3%,

0.5%. Cng thc c th ca qu trnh phi trn c th hin bng b n di.

Bng 4.1: Cng thc phi trn cc mu sa

C CT1 CT2 CT3

Sa bt gy (%w/w) 30.0 30.0 30.0 30.0

Du nnh (%w/w) 10.0 10.0 10.0 10.0

Lecithin (%w/w) 0.5 0.5 0.5 0.5

Maltodextrin (%w/w) 5.5 5.3 5.2 5.0

Lactose (%w/w) 2.0 2.0 2.0 2.0

Nc (%v/w) 52.0 52.0 52.0 52.0

Dch chit l i (%w/w) 0 0.2 0.3 0.5

FeSO4 (mg/100g DW) 8.5 8.5 8.5 8.5

Sau khi phi trn hon tt, dch c em i ng ha, thanh trng v sy

phun thnh bt sa. Mt phn dch sa sau khi thanh trng c ly phn tch

cc ch tiu ha l gm hm lng polyphenol tng, flavonoid, kh nng chng oxy

ha, kh st.

Theo nghin cu ca Tugba Ozdal, Esra Capanoglu v Filiz Altay (2013),

polyphenol khi thm vo sa - mi trng giu protein - th xy ra vic gim hm

lng polyphenol do xut hin lin kt gia polyphenol v protein. Lng

polyphenol t do ny c vai tr quyt nh v kh nng chng oxy ha cng nh

tng thi gian bo qun. Polyphenol trong dch chit l i c flavonoid chim hm

lng ln nht v nh hng ln ti lng polyphenol tng thu c, hp cht ny

cng c bn cht l polyphenol v c kh nng chng oxy cao gp phn khng nh

trong vai tr bo qun, khng khun (Massimiliano Tattini, 2012). V vy cn kim

tra hm lng v kh nng chng oxy ha ca polyphenol c trong dch sa trc

khi sy phun v sa bt sau khi sy phun cho tng cng thc phi trn.

Tip theo, chng ti tin hnh kim tra cc ch tiu vt l v ha l ca bt

sa: hm lng bo, bo t do v protein, ha tan, tnh thm t, tnh chy, t


30

trng, chp qut knh hin vi in t (scanning electron microscopy - SEM), nh

gi cm quan, o gi tr peroxyde. Kt qu nh gi bt sa c so snh vi tiu

chun ca Vit Nam, cc khuyn ngh ca CODEX v vi cc nghin cu khoa hc.

Bn cnh , chng ti tin hnh song song nh gi shelf life ca sn phm

2 mc nhit 45 v 550C. Gi tr peroxyde v thi hn s dng c lin quan cht

ch vi nhau (Wills and Cheong, 1979) nn chng ti xc nh nh hng ca vic

b sung dch chit n thi hn s dng ca sa bt thng qua gi tr peroxyde.

Ngoi ra, trong nhiu sn phm s thay i v cm quan xy ra trc khi c cc

thay i v vt l, sinh hc v ha hc gy nguy c nh hng n sc khe ngi

tiu dung (Gimnez v cng s, 2012). Do , nh gi cm quan cng l mt yu

t quan trng cn c kim tra c th nh gi shelf life ca sn phm.

Bt sa sau khi sy phun c bao gi bng bao b giy nhm, mi loi bt

c bao gi gm 20 gi c khi lng 1 g/gi xc nh gi tr peroxyde, 20 gi

c khi lng 25 g/gi nh gi cm quan. Sau , tt c mu bt c t vo

t gia tc shelf life 2 mc nhit 45 v 550C, m 80% v c ly mu kim

tra u n 4 ngy/ln cho n khi kt thc kho st. Vic nh gi cm quan nhm

xc nh thi im h hng ca sn phm t xc nh im kt thc kho st.

Kt qu nh gi cm quan c a ra bi cc chuyn gia cm quan. Mu c

gi i nh gi cm quan 4 ngy/ln v mi mu s nhn c kt qu nh gi:

t hoc Khng t. Khi kt qu ca mu c tr v l Khng t th dng

kho st cho mu .

2.3. Phng php xc nh

2.3.1. Xc nh m (Nguyn Vn S v Bi Th Nhun, 1990)

Nguyn tc: Phng php ny l da trn nguyn l lm kh mu nhit 105oC

n khi lng khng i, khi lng mu mt i khi sy mu n khi lng

khng i l lng nc c trong mu.

2.3.2. Xc nh hm lng tro (Trn Bch Lam v cng s, 2010)

Nguyn tc: Tro c xc nh bng cch t cc cc nung cha mu vo l nung

trong khong 3 gi nhit 6000C.


31

2.3.3. Xc nh hm lng polyphenol tng (Bajcan v cng s, 2013)

Nguyn tc

c dng xc nh tng hm lng polyphenol, phng php Folin

Cieucalteu phn ng thng qua qu trnh oxy ha ca cc hp cht phenolic s dng

mt hn hp ca axit phosphotungstic (H3PW12O40) v phosphomolybdic

(H3PMo12O40) trong mi trng kim (Adriana Bramorski, Adriana da Rosa

Cherem, 2010). Thuc th Folin Ciocalteu l mt hn hp quan trng khng th

thiu trong phng php ny gm acid phosphotungstic v acid phosphomolybdic.

Trong mi trng kim, cc hp cht phenolic s kh thuc th thnh tungstene

oxide (W8O23) v molybdene oxide (Mo8O23) c mu xanh (blue), hp thu cc i

bc sng 765 nm. Cng mu xanh phn nh hm lng polyphenol phn

ng c trong mu. Dng acid gallic lm cht chun.

Ha cht v cch tin hnh

Thuc th Folin-Ciocalteu.

Dung dch natri carbonate 20% (w/v).

Dung dch chun acid gallic 500 ppm xy dng ng chun.

Cch tin hnh

ng chun acid Gallic c xy dng: ly 1 ml dung dch acid gallic vi

nng khc nhau cho vo cc ng nghim c nh s. Thm 0.25 ml thuc

th Folim Ciocalteu, 3 ml dung dch Na2CO3 20% c th m vo sau , ri lc

u. Sau th m nc cho cc ng nghim c cng th tch l 10 ml. Lc u.

yn trong 1h30 pht ti nhit phng v c trong ti trnh sng, tin hnh o

quang bc sng 765 nm.

o mu: Thay 1 ml cht chun bng 1 ml mu, xc nh hp thu A tng

t nh tr n. T th ng chun, xc nh c hm lng polyphenol tng c

trong mu nghin cu.

Tnh kt qu

Hm lng Polyphenol c trong 100g cht kh dch sa


32

X=

Trong :

Cx l nng polyphenol o c (mg/l)

N l s ln pha long.

M l khi lng dch trc pha long(g)

Ts l nng cht kh c trong dch trc pha long (g/g)

2.3.4. Xc nh hm lng flavonoid tng (Nie v cng s, 2011)

Nguyn tc

Cc kim loi thng tham gia trong qu trnh to phc l st, nhm v

magie. Trong , phc kim loi ca flavonoids c mu cn mu vng l phc

kim loi ca carotenoid v aurone l mt flavonoid to mu vng cho hoa v mt

s cy cnh. Mu sc ca anthocyanin th ph thuc vo pH (mu trong acid,

mu xanh trong bazo). Mt s cu trc c kh nng to phc kim loi l: ortho-

dihydroxyl phenol, 3-hydroxychromones, 5-hydroxychromones v ortho-

hydroxylcarbonyl. Cu trc ca cc phn t nh hng n vic xc nh cc phn

ng vi ion kim loi v s hin din ca cc ion kim loi s nh hng n tnh

cht ha hc ca cc phc cht (Vermerris - Ralph Nicholson, 2006).

Hnh 7.2: Mt s cu trc c kh nng to phc kim loi


33

Theo Chang v cng s (2002), nguyn tc c bn ca phng php so mu

nhm clorua l s to phc bn ca AlCl3 vi nhm C-4 keto hoc mt trong hai

nhm hydroxyl C-3 hoc C-5 ca flavone hoc flavonol. Ngoi ra, AlCl3 to phc

khng bn vi nhm orthodihydroxyl trong vng A hoc vng B ca flavonoid.

Nhng phc cht hnh thnh bi flavonol v nhm hydroxyl C-3 hoc C-5 l

galagin, morin v kaemprefol hoc mt s hp cht c nhm ortho-dihydroxyl

(rutin, quercitin, quercitrin v myricetin).

Cch tin hnh

Theo phng php xc nh hm lng flavonoids tng ci tin da theo

vic to mu vi nhm clorua c Nie v cng s (2011) trnh by. S dng

cht chun l rutin xc nh hm lng flavonoid tng. S dng 0.01 gam ca

rutin c khi lng chnh xc v c ha tan trong ethanol 99.95%. Dung dch

rutin sau khi ha tan c nh mc bng ethanol 99.95% ti th tch l 10 ml.

Dung dch rutin c chun b vi nng 1 (mg/ml).

Xy dng ng chun

By ng nghim c chun b v c nh s t 0 n 6, tng ng vi 0,

0.1, 0.2, 0.3, 0.4 v 0.5 ml cht chun rutin. Sau , th m 0.5 ml NaNO2 5% vo tt

c cc ng nghim, sau lc u trong 5 pht.

Thm tip 0.5 ml ca Al(NO3)3 10% v tip tc lc 5 pht. Sau , th m 4 ml

NaOH 4% v th m nc cho th tch cc ng nghim bng nhau. Tip tc, lc 15

pht. Sau , tin hnh o quang bc sng 510 nm.

T th ng chun ta xc nh c hm lng flavonoid c trong mu

nghin cu v mu i chng vi n v tnh l mgRE/100g cht kh.

Tnh kt qu

Hm lng flavonoid c trong 100g cht kh dch sa

X=


34

Trong :

Cx l nng flavonoid o c (mg/l).

N l s ln pha long.

M l khi lng dch trc pha long (g).

Ts l nng cht kh c trong dch trc pha long (g/g).

2.3.5. Xc nh ho t tnh chng oxy ha bng phng php DPPH

(Nihal Turkmen, 2005)

Nguyn tc

Phng php DPPH c da trn vic gim DPPH, n nh gc t do.

DPPH (2,2 diphenyl 1-1- prylhydrazyl) l mt gc t do bn vi mt electron l

cho mt s hp th ti a 517 nm (mu tm). Khi c mt cht chng oxy ha,

DPPH b kh thnh diphenylpicrylhydrazine c mu vng do kh nng nhn hydro

ca cc cht ny. Khi mt dung dch DPPH l hn hp vi mt cht c th nhng

mt nguyn t hydro, iu ny lm gim (Diphenylpicrylhydrazine; khng trit )

mt mu tm. S gim hp thu ti bc sng 517 nm cho php xy dng ng

cong c ch tnh theo nng , t xc nh c hot tnh chng oxy ha thng

qua gi tr IC50 (nng cht chng oxy ha m ti 50% DPPH b c ch).

Hnh 8.3: Phn ng chuyn DPPH (gc t do) sang DPPH (lin kt)

Cch tin hnh

Ly 1 ml dch chit nhng nng khc nhau cho vo ng nghim c np.

Thm vo 4 ml thuc th DPPH 6.5 x 10-5

M. Sau cc ng nghim ny c gi

trong bng ti nhit phng trong 30 pht phn ng xy ra hon ton. Mu


35

i chng (control) l mu cha DPPH v s dng nc ct thay th dch chit.

S gim hp thu ti bc sng 517 nm c o bng thit b o quang UVVis

v lng DPPH s c tnh ton.

Tnh kt qu

Hot lc loi tr gc t do (radical scavenging activity) (%) =

*100%

Trong :

A0 l hp thu ca mu i chng.

A1 l hp thu ca mu c hp cht chng oxy ha.

Hot tnh chng oxy ha sau c hi quy qua gi tr hp thu ca mu v c

th hin bng gi tr IC50 .

2.3.6. Phng php kh st

Nguyn tc

Theo Apak v cng s (2013), phng php kh st dng o lng kh

nng chng oxy ha ca polyphenol nh s c mt ca hp cht ferricyanide, ion

st b oxy ha thnh st (II). Phng php c mt ferricyanide cho ph xanh

c s dng cho vic o lng kh nng kh. Vic s dng ng thi cc ion

ferricyanide v Fe (III) nh mt cht to mu cho qu trnh kh din ra thun li

hn. Ta c phn ng:

Potassium ferricyanide + Ferric chloride Potassium ferrocyanide +

ferrous chloride

Bc sng hp thu cc i ca phng php ny l 700 nm.

Cch tin hnh

Dch vi cc nng khc nhau c trn vi 2.5 ml dung dch m

phosphat (0.2M, pH = 6,6 ), thm tip 2.5 kali ferricyanide 1%. Lc u, sau

mang 50C trong 20 pht. ngui, theo tip 2.5ml acid trichloroacetic 10%,

lc u. Sau tin hnh ly tm 3000 vng/pht trong 10 pht, ht ly 2.5 ml


36

phn trn cho vo ng nghim, thm tip 2.5ml nc ct v 0.5 ml st vo.

y n trong 10 pht phn ng. Sau tin hnh o quang bc sng 700nm (J.

Chem, 2011).

Tnh kt qu

So snh kh nng kh ca ca polyphenol v Vitamin C.

2.3.7. Xc nh acid trong sa (Israr ul Haq v cng s, 2013)

Nguyn tc: S dng dung dch kim mnh NaOH trung ha acid yu c trong

dch sa. Do cn bng phn ng s lch v pha kim nn s lm chuyn mu ca

dch t trng c sang mu hng khi c mt ca cht ch th phenolphthalein.

2.3.8. Xc nh hm lng bo (TCVN 7084:2002)

Nguyn tc: Chit phn mu th trong dung dch etanol cha amoniac bng ete

dietyl v du nh. Loi b dung mi bng cch chng ct hoc lm bay hi. Xc

nh khi lng ca cc cht chit c.

2.3.9. Xc nh hm lng bo t do v hiu qu vi bao

Hu ht cc loi du khng n nh v mt ha hc v d b oxy ha, c bit

l khi tip xc vi oxy, nh sng, m v nhit . y l nguy n nhn lm mt

cht lng dinh dng v xut hin cc hng v v hp cht khng mong mun,

nh hng n s n nh trong thi gian bo qun v cc c tnh cm quan ca

du v cc sn phm c du (Patricia Calvo, 2010). V vy, cn xc nh lng bo

t do cha c vi bao c th nh hng ti cht lng sn phm.

Nguyn tc

Bt c cn mt khi lng chnh xc v c ra nhanh vi dung mi hu

c tch bo trn b mt ca bt ra khi sau cn khi lng cn li bit

lng bo b mt.

Tin hnh

Mt gam bt c cn chnh xc trn giy lc v ra sch vi 5 ml

petroleum ether (40-60C). Thao tc ny nn tin hnh trong vng 10 giy. Phn bt

cn li c sy kh trong chn khng nhit phng cho n khi t c khi


37

lng khng i. Gi tr b mt i khi tch bo c ghi li l bo b mt g/g bt.

Kt qu l trung bnh ca cc ln lp phn tch (Esther H.-J. Kim, 2005).

Tnh kt qu:

Hm lng du t do c tnh theo phn trm tr n tng bo (Patricia

Calvo, 2010).

Hiu qu vi bao

2.3.10. Xc nh tnh n nh h nh tng ( Donz, 2013)

Trong sa tn ti h nh tng du trong nc v tnh n nh ca h nh

tng ny phn nh cht lng ca sa v cm quan ca sa. Phn ln nh tng l

cc ht cu bo. Cc ht cu rt nh, mt git sa cha khong mt triu ht cu

ny. V cht bo trong sa phn tn rt mn v n c tiu ha d dng hn so vi

cht bo t bt k ngun no khc nn du thng c b sung vo thc phm c

bit l sa. H nh tng cht bo c n nh da trn lin kt phospholipid v

protein c hp th trn b mt ca git. Cc git bo ny nh hn nc v kt

hp li khi chng gn nhau, cui cng chng ni ln b mt ca sa to thnh mt

lp kem.

Tin hnh:

Hon nguyn 10g bt vo 100 ml nc cho vo ng ong. yn trong 20

pht. Ht 50 ml dch y ca ng ong (pha thp hn). Tng hm lng cht bo

ca mi pha c xc nh theo phng php Adam- Rose. Ch s n nh c

tnh da tr n % hm lng cht bo gia 2 pha.

Tnh kt qu

SI =

S khc bit gia 2 kt qu phn tch trn cng 1 mu l nh hn 8%.

Ch s ny >80% c ngha l khng c s tch vng.

Nu ch s ny


38

2.3.11. Xc nh hm lng protein (Tommy N, 2009)

Theo nghin cu ca Dimas A. M. Zaia (2003) phng php Bradphod l

phng php o quang nhy v kt qu chnh xc nht i vi sa bt gy v cc

loi sa bt khc hin nay v vy trong th nghim ny chng ti tin hnh xc nh

theo phng php Bradphod.

Nguyn tc

Phng php xc nh protein ny c da trn vic lin kt vi mt loi

thuc th Coomasie Brilliant Blue vi protein. Mc lin kt vi cc protein khc

nhau thay i theo s lng axit amin b n trong protein . Thuc th lin kt vi

protein di dng anion v hp th cc i 595nm. Nng protein ca mu

c o bng cch o hp th 595 nm.

Thuc th: 100 mg Coomasie Brilliant Blue G-250 ha tan trong 50ml

ethanol 95%. Dung dch c trn vi 100 ml dung dch 85% axit photphoric v

nh mc l n 1 lt nc.

Dung dch protein chun: Abulmin huyt thanh b c pha nng 1

mg/ml trong nc ct c s dng nh l cht chun v c bo qun lnh.

Tin hnh

Pha long abulmin ( chun b trc l dch protein chun) c pha long

vi nc ct. Phi c t nht 5 nng khc nhau c tin hnh gia khong nng

0,1-0,5 mg/ml. Nc c s dng thay cho dung dch protein lm mu trng

(ZERO) khi Set Blank. Mu sa cn o c pha long tng t nh pha long

dung dch chun sao cho c t nht hai im ca im pha long nm trong ng

chun. o hp th 595 nm sau 5 pht nhng trc 1 gi.

Tnh kt qu

Hm lng protein c trong 100g cht kh dch sa:

X=

Trong :

Cx l nng protein o c (mg/l).


39

N l s ln pha long.

M l khi lng dch trc pha long (g).

Ts l nng cht kh c trong dch trc pha long (g/g).

2.3.12. Xc nh ha tan (Moreira v cng s, 2009)

Nguyn tc: ha tan trong nc c xc nh bi nng khi lng

bo ha ca cc cht ha tan trong nc v l mt hm theo nhit .

Cch tin hnh: Cho 1g bt vo 100ml nc. Khuy u bng my khuy

t vi tc 385g trong 5 pht. Ly tm dung dch thu c vi tc 2600rpm

trong 5 pht. Ly 25ml phn dch ni l n tr n sau khi ly tm v cho vo a petri

kh bit trc khi lng. Cn xc nh li khi lng bt tr n a petri

Kt qu:

ha tan = (m3 m2)4

Hiu qu ha tan (H) =

Trong :

m1: Khi lng bt (g)

m2: Khi lng a petri sy kh (g)

m3: Khi lng a v bt sau khi sy 25 ml dch (g)

H: Hiu qu ha tan (%)

2.3.13. Xc nh tnh chy ca bt ( Moreira v cng s, 2009)

Nguyn tc: Gc ngh l mt phng php ng tin cy, nhanh chng v

n gin o kh nng chy ca cc loi bt khc nhau. Gc di tng ng vi

bt chy t do, trong khi nhng gc cao hn ch ra tnh chy ca bt kt dnh hay

ri. ISO 3435 s dng k thut ny xc nh s c kt ca khi nguyn liu

(Cain, 2002).

Cch tin hnh: Tnh chy ca bt c xc nh da trn gc hnh thnh

gia mt b n v y ca hnh nn c to ra khi 10g bt t mt phu c chiu

cao c nh ln mt phng (thng thng l 20 cm).


40

Kt qu: (T.A. Shittu, M.O. Lawal, 2007)

Bng 5.2: Kt qu nh gi kh nng chy ca bt

Gc nh gi kt qu:

35o Bt kh ri,

35-45o Bt kh dnh

45-55o Bt b bt dnh

>55o Bt cc k dnh

2.3.14. Xc nh tnh thm t ca bt (Winston Duo Wu v cng s,

2014)

Nguyn tc: Tnh thm t ca bt l thi gian cn thit lm t hon

ton bt, khi n c th vo nc nhit xc nh.

Cch tin hnh: Cho 1g bt ri t mt phu cha c chiu cao c nh vo

100 ml nc 40oC (www.niro.com). Quan st v tnh thi gian t lc bt

u cho n khi bt chm khi b mt nc.

Tnh kt qu

Nu bt khng b t sau 5 pht th dng li v a ra kt qu l > 300 giy.

2.3.15. Xc nh t trng ca bt (T.A. Shittu, M.O. Lawal, 2007)

Nguyn tc: T trng khi ca bt l trng lng ca bt chia cho th tch

n chim, thng th hin nh g/ml hoc kg/l.

Cch tin hnh: Mu sau khi sy c gi kn bng 2 lp bao nhm trnh

ht m. Sau khi n ni cn g t trng sm trnh mu b ht m. Cn 50g bt

vo ng ong 100ml bng nha. G 625 bng thit b g t trng (PT-200,

Pharticeul) vi chiu cao g 3 mm, tc g 300 ln/pht.

Tnh kt qu:

T trng = s g bt/ml bt sau khi g t trng.

2.3.16. Xc nh peroxyde (Shantha v Decker, 1994)


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Nguyn tc

Phng php ny c da trn kh nng ca hydroperoxydes oxy ha

cc ion st ( thnh cc ion st ( ) trong mi trng axit. Cc ion st to

phc vi thiocyanateto thnh chromophore, m phc ny c th c o bng

quang ph (Eymard v Genot, 2003). Thiocyanate st l mt phc mu tm vi

quang ph hp th ti 500 nm.

Cch tin hnh

Cc phng php quang ph c m t bi Shantha v Decker (1994)

c s dng xc nh cc PV. Mu du ( 0.01 0.3 g), ty thuc vo mc

peroxy) c cha trong erlen sau trn 9,8 ml hn hp chloroform-methanol

(7:3 v/v) vo ri trn trn mt my trn vortex 2 - 4 s. Dung dch amoni thiocyanate

(50 ml, 30% w/v) c thm vo tip theo v mu c trn bng my trn

vortex trong 2 - 4 s. Sau , 50 ml dung dch st (II) clorua ([0,4 g bari clorua

dihydrate ha tan trong 50 ml H2O] + [0,5 g FeSO4. 7H2O ha tan trong 50 ml

H2O] + 2 ml 10 M HCl, lc ta Ba ra c dung dch trong]) c thm tip

vo erlen, v mu c trn ln trn mt my trn vortex 2 - 4 s. Sau 5 pht

nhit phng, hp th ca mu s c o 500 nm so vi mu trng (mu

trng l mu c cha tt c cc tc nhn phn ng ngoi tr mu) bng cch s

dng mt my quang ph. Ton b qu trnh c thc hin trong nh sng du v

hon thnh trong vng 10 pht. Kt qu c th hin trong ml nglng oxy/kg

du.

Tnh kt qu

PV(mequiv peroxyde/kg of mu)

Trong :

l hp th ca mu 500 nm

l hp th ca mu trng 500 nm

m l dc ca Fe (III) hiu chun


42

55,84 l khi lng nguyn t ca Fe

2 l yu t chuyn i milliequivalents (mequiv) Fe mequiv ca peroxyde

l khi lng mu tnh theo gam.

2.3.17. K thut knh hin vi in t qut (SEM)

Phng thc c bn ca SEM l chp hnh nh v b mt vt liu dng cho

vic nghin cu kt cu, hnh thi, b mt v phn gii ti a vo khong 10 nm.

SEM c coi l mt cng c trc quan b mt vt liu, cc chm tia in t c th

xuyn qua tng micromet bn trong mu. Bng cch chn nng lng ca chm tia

ti v thu nhn cc electron tn x ngc, cc thng tin c trng kch thc b

mt ca vt mu c th c ghi nhn. Mt chui cc hnh nh thu c bng cch

thay i nng lng ti v ra thch hp. Sau , to ra mt trnh t cc lp ct

quang hc ca mu, c th xy dng li thnh hnh nh khng gian ba chiu (Joy,

1997).

Theo nghin cu ca Egerton (2005), trong h thng chp SEM, mt ngun

electron c tp trung trong mi trng chn khng v c pht qua u d, sau

l qut tr n b mt ca mu vt. Cc chm tia in t qut qua cun dy v thu

knh mc ti u iu ny lm chch hng theo chiu ngang v chiu dc cc

chm tia c th qut trn b mt ca mu. Cc electron xuyn qua b mt, mt s

tng tc c th xy ra dn n s pht x ca cc electron hay photon, s to nh

trong SEM v cc php phn tch c thng qua vic phn tch cc bc x ny.

Hnh 2.4: Tng tc gia b mt vt liu v chm tia


43

phng i c tnh bng cng thc sau:

phng i =

SEM hot ng trn mt in p t 2 n 50kV v ng knh chm tia

qut mu l t 5nm 2m. Nguyn tc cho s hnh thnh cc hnh nh trong chp

SEM l gm ba loi: hnh nh electron th cp, hnh nh electron tn x ngc v

bn tia X-ray (X-ray map). Electron th cp v tn x ngc c quy c theo

nng lng ca chng. Khi nng lng ca cc electron pht ra t hn 50eV, n

c gi l electron th cp hoc electron tn x ngc c xem xt n vic thot

ra ca cc electron vi nng lng ln hn 50eV.

Hnh 2.5: Cu hnh ca thit b chp SEM

2.3.18. Phng php so mu Minolta (Isabel v cng s, 2013)

Mu sc l mt thuc tnh quan trng c nh hng n s yu thch ca

ngi tiu dng i vi cht lng sn phm. Mt s sc t trong thc phm, c

o lng bng cc thit b o mu. Hin nay, vic nh gi mu sc c s thay

i ca mu sc theo cc thng s CIELAB. Mt s hp cht to nn mu cho sn

phm l phenolics, carotenoids, chlorophyll trong nhng iu kin x l khc nhau.

Mi tng quan gia cc hp cht ny v s thay i v mu sc ca mt s thc

phm l rt ln (R > 0.72) theo phn tch Pearson.


44

Mu c trng thng c ly t nhng khng gian mu khc nhau nh

RGB (, xanh l cy, xanh dng) v HSI (sc thi mu (Hue), bo ha v

cng mu) bng nhng phng php thng k . Do , vic nh gi nhng

thng s ny din ra trong thi gian ngn. Nhng nm gn y, c nhiu nghin cu

tp trung vo vic nh gi s c mt ca cc hp cht sinh hc i km vi hot

ng chng oxy ha nh carotenoids, anthocyanin, polyphenol, chlorophyll

Nguyn tc

Cc thng s mu sc c trong khng gian mu CIELAB c biu din

di y:

Hnh 2.6: Khng gian mu CIELAB

Trong khng gian mu CIELAB, c mt ch s v cng sng (L*) v

hai ta mu (a* v b*). Ch s L* c li n quan n sng, mi mu sc c th

c xem nh mt b phn ca thanh mu xm (grey bar), trong mu en

(L*=0) v trng (L*=100). Ta a* c gi tr m s cho mu xanh l cy v gi tr

dng cho mu . Ta b* c gi tr dng cho mu vng v gi tr m cho mu

xanh dng. Ngoi ra, cn mt s gi tr t tng mu khc bit (total colour


45

difference - E*), sc (C*ab) v sc thi mu (hue) cng cung cp nhng thng

tin c gi tr.

Tnh kt qu

Gi tr E* l quan trng khi dng nh gi mi quan h gia mu sc v

phn tch thng k ; n c tnh bng khong cch gia hai im trong cu trc

khng gian elip ba chiu c xc nh bng ta L*, a*, b*. Tnh bng phng

trnh:

**** Lba

Sc v sc thi mu (hue) dng nh lng v nh tnh cho thuc tnh

mu sc. Sc cho bit bi n m nht ca mu sc, trong khi gi tr sc thi

mu l thuc tnh da trn cc mu sc nh ngha theo cch truyn thng nh

, vng, cam. Gi tr chroma v hue c tnh theo phng trnh sau:

**2* baCab

hab = arctan(b*/a*)lc o + a*+ b* (gc phn t th I)

hab = 180 + arctan(b*/a*)lc o a*,b* (gc phn t th II) a*,b* (gc phn

t II)

hab = 360 + arctan(b*/a*)lc o + a*,-b* (gc phn t th IV)

Cc gi tr ca ng cong phn phi ca nng lng chiu sng da trn gi

tr o lng ca nh sng ban ngy: D55, D65 v D75. Cc gi tr ny c xc nh

khc nhau vi bc sng thay i t 300 830 nm. D65 l ngun sng thng c

s dng. C hai tiu chun quan st chung l: 100 v 2

0. D65 v 10

0 l gi tr thng

c s dng nht.

Tin hnh

Mu c chun b v t tr n a nha lm t polyethylene v c t

chnh gia mt knh. iu kin l b mt v dy phi ng u o c

CIELAB vi ta l D65 v 100. Ghi nhn s liu L*, a*, b*, E*. Sau , tnh


46

ton theo cng thc pha trn. Mi php o c lp li 10 ln (Telis v Martinez-

Navarrete, 2010).

2.3.19. Phng php x l s liu

Tt c cc th nghim u c lp li 3 ln. Kt qu th nghim trnh by

trong bo co ny l gi tr trung bnh ca 3 ln lp li.

S dng ANOVA trong phn mm Stagraphic kim tra s khc bit cc

kt qu l c ngha hay khng ( = 0.05). Khi P value < 0.05 th s khc bit ca

cc kt qu c ngha thng k.


47

3. CHNG 3 KT QU V BN LUN

3.1. Kt qu nh gi lng polyphenol, kh nng chng oxy ha ca dch

chit l i trong dch sa trc sy phun v bt sau sy phun

3.1.1. Hm lng polyphenol tng (TPC) v flavonoid tng (TFC)

Hin nay c nhiu cht chng oxy ha c s dng vi liu lng thp

nn ch c gii hn s dng ti a l 0.1% (Grayna Budryn, 2013). Nhng

nghin cu gn y cho thy liu lng polyphenol c b sung vi liu lng ln

hn 0 200 mg/100 ml sa (T.F. Wegrzyn, J.M. Farr, 2007), 0.3%, 0.6 % v 0.9 %

trong yoghurt (Mohammad Hossein Marhamatizadeh, 2013), hot tnh cao hn c

hiu qu ko di s n nh ca cht bo trong thc phm tt hn so vi cht chng

oxy ha tng hp (Grayna Budryn, 2013). Chng ti tin hnh kho st hm lng

dch chit b sung vo dch sa vi 3 mu CT1, CT2, CT3 vi hm lng tng

ng l 0.2 %, 0.3% v 0.5% cht kh dch chit/cht kh sa.

Bng 6.1: Kt qu hm lng polyphenol v flavonoid trc sau sy phun

Ch tiu

Mu

Hm lng polyphenol

(mgGAE/100gDW)

polyphenol han che hien tuong cu

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