Thử Nghiệm Chế Biến Nước Uống Hỗn Hợp Từ Nguyên Liệu Rong Sụn Và Dâu Tây - P1

LI CM N

Tri qua thi gian hc tp v nghin cu ti trng, ti nhn c s dy

d v ch bo tn tnh ca cc thy c gio. Cng vi s quan tm chm sc v ng

vin ca gia nh, b bn v s n lc ca bn thn, ti kt thc kha hc v

hon thnh n tt nghip ca mnh.

Trc ht xin chn thnh cm n nh trng v cc thy c to iu kin

cho ti c hc tp v nghin cu ti trng.

Ti xin by t lng bit n su sc n c Minh Phng tn tnh hng

dn v gip ti trong sut qu trnh thc hin n ny.

c bit xin c ghi nh s gip ca c Nguyn Th Tuyt Mai v c

Nguyn Th Thc cng cc thy c trong khoa Ch Bin gip v ng vin

ti trong sut qu trnh hc tp v nghin cu.

Xin chn thnh cm n cc thy c ph trch phng th nghim, cc anh ch, b

bn gip v chia s cng ti trong qu trnh thc tp.

Con xin cm n gia nh lun l ch da vng chc, lun ng vin v ng

h con trong sut thi gian hc tp.

Nha Trang, thng 11 nm 2008

Sinh vin thc hin

ng Th Thy Phng

more.edu.vn

MC LC Trang

M U ........................... ERROR! BOOKMARK NOT DEFINED.

CHNG 1....................................................................................... 3

TNG QUAN ..................................................................................... 3 1.1. TM HIU V NC UNG NG CHAI.................................................3

1.1.1. Gii thiu v hp nc ung.............................................................3

1.1.2. Cc qu trnh c bn trong sn xut hp nc ung khng gas. .........5

1.1.3. Tnh hnh pht trin nc gii kht Vit Nam ......................................8

1.1.4. H vi sinh vt trong hp rau qu ........................................................9

1.1.5. Phng php thanh trng nhit bng nc ............................................10

1.2. TM HIU V NGUYN VT LIU .........................................................15

1.2.1. Nguyn liu chnh.................................................................................15

1.2.2. Nguyn liu ph - ph gia gia v ........................................................24

1.2.3. Bao b thy tinh ....................................................................................28

CHNG 2.......................................................................................................30

MC CH - I TNG V PHNG PHP .............................................30

NGHIN CU ..................................................................................................30

2.1. MC CH NGHIN CU .......................................................................30

2.2. I TNG NGHIN CU......................................................................30

2.2.1. Nguyn liu chnh.................................................................................30

2.2.2. Cc nguyn liu ph .............................................................................30

2.3. PHNG PHP NGHIN CU ................................................................31

2.3.1. Quy trnh d kin..................................................................................31

2.3.2. S ni dung nghin cu. ..................................................................33

2.3.3. Phng php nh gi cht lng sn phm .........................................34

2.4. B TR TH NGHIM. ..............................................................................36

2.4.1. Th nghim xc nh ch x l rong nguyn liu..............................36

more.edu.vn

2.4.2. Th nghim xc nh cc thng s trong qu trnh nu chit.................42

2.4.3. Th nghim xc nh cng thc phi ch..............................................44

2.4.4. Th nghim xc nh ch thanh trng ...............................................49

2.5. DNG C V THIT B............................................................................51

2.6. PHNG PHP LY MU V X L MU..........................................51

2.7. PHNG PHP X L S LIU .............................................................51

CHNG 3 ...................................................................................... 52

KT QU NGHIN CU V THO LUN ........................................... 52 3.1.Kt qu xc nh ch x l rong nguyn liu............................................52

3.1.1. Kt qu x l bng acid acetic. .............................................................52

3.1.2.Kt qu x l bng phng php ngm phi..........................................60

3.2. Kt qu xc nh ch nu chit...............................................................64

3.2.1. Kt qu xc nh tc ht nc trung bnh ca rong trong nc trc

khi nu chit ...................................................................................................64

3.2.2. Kt qu xc nh t l nc nu/rong....................................................65

3.2.2. Kt qu xc nh thi gian nu chit nc rong ....................................66

3.3. Kt qu xc nh cng thc phi ch............................................................68

3.3.1. Kt qu xc nh t l pha long: nc/dch rong ................................68

3.3.2. Kt qu xc nh dch chit du b sung ...............................................69

3.3.3. Kt qu xc nh lng cht mu b sung.............................................71

3.3.4. Kt qu xc nh nng ng ..........................................................72

3.3.5. Kt qu xc nh nng acid citric .....................................................73

3.3.6. Kt qu xc nh hm lng tinh du b sung.......................................75

3.4. Kt qu xc nh ch thanh trng .............................................................77

3.4.1. Kt qu xc nh s nh hng ca nhit n nht ca bn thnh

phm trong qu trnh thanh trng....................................................................77

3.4.2. Kt qu xc nh cng thc thanh trng................................................78

3.5. xut quy trnh sn xut ...........................................................................79

3.5.1. S quy trnh .....................................................................................79

more.edu.vn

3.5.2. Thuyt minh quy trnh ..........................................................................80

3.6. Sn xut th nghim v tnh gi thnh sn phm..........................................82

3.6.1. Sn xut th nghim .............................................................................82

3.6.2. S b tnh gi thnh sn phm ..............................................................83

KT LUN V XUT KIN....................................................... 85

TI LIU THAM KHO..................................................................... 87

more.edu.vn

Bng 1.1: Ch tiu sn lng ru - bia - nc gii kht nm 2008 ................... 9

Bng 1.2: Hm lng axt amin ca rong sn............................................. 17

Bng 1.3: Thnh phn ha hc ca rong sn .............................................. 17

Bng 1.4: Thnh phn ho hc ca qu du ty .......................................... 23

Bng 1.5: Ch tiu vi sinh vt c trong ng trng v ng tinh luyn........... 25

Bng 2.1. Bng h s quan trng cho cc ch tiu........................................ 34

Bng 2.2. Thang im cm quan sn phm nc ung rong sn du ty ......... 35

Bng 2.3: Bng phn cp cht lng theo quy nh ..................................... 36

Bng 2.4: Thi gian ngm rong trong nc ............................................... 38

Bng 2.5: Thi gian ngm rong trc x l ............................................... 38

Bng 2.6: Nng acid acetic x l ........................................................ 39

Bng 2.7: Thi gian x l rong bng acid acetic ......................................... 39

Bng 2.8: T l dung dch acid acetic/rong ................................................ 40

Bng 2.9: T l nc ngm/rong trc khi phi.......................................... 41

Bng 2.10: Thi gian phi rong.............................................................. 41

Bng 2.11: Thi gian ngm rong trong nc.............................................. 43

Bng 2.12: T l nc nu/rong ............................................................. 43

Bng 2.13: Thi gian nu chit nc rong................................................. 44

Bng 2.14: T l pha long nc/dch rong ............................................... 45

Bng 2.15: Lng dch chit du ty b sung (ml) ...................................... 46

Bng 2.16: Lng cht mu b sung (ml) ................................................. 47

Bng 2.17: Nng ng (%) .............................................................. 47

Bng 2.18: Nng acid citric (%) ......................................................... 48

DANH MC BNG

more.edu.vn

Bng 2.19: Hm lng tinh du b sung (ml)............................................. 49

Bng 2.20: Nhit thanh trng (0C) ...................................................... 50

Bng 2.21: Thi gian gi nhit ............................................................... 50 Bng 3.1: Trng thi cm quan v im cm quan trung bnh ca cc mu th

nghim xc nh thi gian ngm rong trong nc thng.............................. 54 Bng 3.2: Trng thi cm quan v im cm quan trung bnh ca cc mu th

nghim xc nh nng acid acetic x l ................................................ 55 Bng 3.3: Trng thi cm quan v im cm quan trung bnh ca cc mu th

nghim xc nh thi gian x l rong bng acid.......................................... 57 Bng 3.4: Trng thi cm quan v im cm quan trung bnh ca cc mu th

nghim xc nh t l dung dch acid/rong ................................................ 58 Bng 3.5: Trng thi cm quan v im cm quan trung bnh ca cc mu th

nghim xc nh t l nc ngm/rong..................................................... 61

Bng 3.6: nh hng ca thi gian phi nng n hiu qu x l rong............. 62 Bng 3.7: nh gi cm quan v im cm quan trung bnh ca cc mu th nghim

xc nh t l nc nu/rong.................................................................. 65 Bng 3.8: nh gi cm quan v im cm quan trung bnh ca cc mu th nghim

xc nh thi gian nu.......................................................................... 67

Bng 3.9: Trng thi cm quan ca dch chit rong sn ................................ 68 Bng 3.10: Trng thi cm quan v im cm quan trung bnh v v ca cc mu th

nghim xc nh lng dch du ty b sung.............................................. 70 Bng 3.11: Trng thi cm quan v im cm quan trung bnh v mu ca cc mu

th nghim xc nh lng cht mu b sung ............................................. 71 Bng 3.12: Trng thi cm quan v im cm quan trung bnh v v ca cc mu th

nghim xc nh nng ng b sung .................................................. 72

more.edu.vn

Bng 3.13: Trng thi cm quan v im cm quan trung bnh v v ca cc mu th

nghim xc nh nng acid citric b sung.............................................. 74 Bng 3.14: Trng thi cm quan v im cm quan trung bnh v mi ca cc mu

th nghim xc nh t l tinh du b sung ................................................ 75

Bng 3.15: Kt qu o nht ca cc mu sau thanh trng .......................... 77

Bng 3.16: Kt qu kim nghim vi sinh................................................... 78

Bng 3.17: Kt qu nh gi cm quan sn phm........................................ 83

Bng 3.18: gi thnh sn phm (tnh cho 1000 n v sn phm) .................... 84

more.edu.vn

Hnh 2.1: S quy trnh d kin sn xut nc ung t rong sn du ty

........................................ ERROR! BOOKMARK NOT DEFINED. Hnh 2.2: S ni dung nghin cu ca ti ........................................... 33 Hnh 2.3: S th nghim xc nh ch x l rong nguyn liu . .. ..ERROR!

BOOKMARK NOT DEFINED.

Hnh 2.4: S th nghim xc nh ch nu chit rong sn . .......... ERROR!

BOOKMARK NOT DEFINED. Hnh 2.5. S th nghim xc nh cng thc phi ch ........................................45

Hnh 2.6: S th nghim xc nh ch thanh trng ................ 49ERROR!


Hnh 1: Nguyn liu rong sn ban u .......... ERROR! BOOKMARK NOT

DEFINED.

Hnh 3.1: Khi lng rong sn theo thi gian ngm... ERROR! BOOKMARK

NOT DEFINED. Hnh 3.2: Mc tng khi lng theo thi gian ngm ..................................... 53 Hnh 3.3: im nh gi cm quan cc mu th nghim xc nh thi gian ngm

rong trong nc thng.......... ERROR! BOOKMARK NOT DEFINED. Hnh 3.4: im nh gi cm quan cc mu th nghim xc nh nng acid acetic

x l.................................. ERROR! BOOKMARK NOT DEFINED. Hnh 3.5: im nh gi cc cm quan ca cc mu th nghim xc nh nng

acid x l ........................... ERROR! BOOKMARK NOT DEFINED.

DANH MC HNH

more.edu.vn

Hnh 3.6: im nh gi cm quan ca cc mu th nghim xc nh t l dung dch

acid/ rong ........................... ERROR! BOOKMARK NOT DEFINED. Hnh 3.7: im nh gi cm quan ca cc mu th nghim xc nh t l nc

ngm/ rong.......................... ERROR! BOOKMARK NOT DEFINED.

Hnh 3.8: S nh hng ca thi gian phi nng n m ca rong..... ERROR!


Hnh 3.9: Khi lng rong sn theo thi gian ngm....................... 64ERROR!

BOOKMARK NOT DEFINED. Hnh 2. Rong sn trc khi nu chit ..........64

Hnh 3.10: im nh gi cm quan ca cc mu th nghim xc nh t l nc

nu /rong ............................ ERROR! BOOKMARK NOT DEFINED. Hnh 3.11: im nh gi cm quan ca cc mu th nghim xc nh thi gian nu

chit nc rong .................... ERROR! BOOKMARK NOT DEFINED.

Hnh 3.12: nh hng ca t l pha long n nht dch chit .... 68ERROR!

BOOKMARK NOT DEFINED. Hnh 3.13: im nh gi cm quan v trng thi ca cc mu th nghim xc nh

t l pha long nc/ dch rong ERROR! BOOKMARK NOT DEFINED. Hnh 3.14: im nh gi cm quan v v ca cc mu th nghim xc nh lng

dch chit du b sung ........... ERROR! BOOKMARK NOT DEFINED. Hnh 3.15: im nh gi cm quan v mu ca cc mu th nghim xc nh lng

cht mu b sung.................. ERROR! BOOKMARK NOT DEFINED. Hnh 3.16: im nh gi cm quan v v ca cc mu th nghim xc nh nng

ng b sung ..................... ERROR! BOOKMARK NOT DEFINED. Hnh 3.17: im nh gi cm quan v v ca cc mu th nghim xc nh nng

acid citric b sung................. ERROR! BOOKMARK NOT DEFINED.

more.edu.vn

Hnh 3.18: im nh gi cm quan v mi ca cc mu th nghim xc nh hm

lng tinh u b sung........... ERROR! BOOKMARK NOT DEFINED. Hnh 3.19: nh hng ca nhit n nht bn thnh phm trong qu trnh

thanh trng ......................... ERROR! BOOKMARK NOT DEFINED.

HNH NH SN PHM ....... ERROR! BOOKMARK NOT DEFINED.

DANH MC CC K HIU CC CH VIT TT

TCVN: Tiu chun Vit Nam

KLTB: Khi lng trung bnh

MTKL: Mc tng khi lng

TB: Trung bnh

TN: Th nghim

more.edu.vn

- 1 -

M U H sinh thi bin ca chng ta v cng a dng v phong ph, trong c rt

nhiu loi c gi tr kinh t cao. Bn cnh ngun ti nguyn hi sn di do th

ngun rong bin cng khng km phn a dng. c bit trong nhng nm gn y,

ngnh nui trng v ch bin rong bin ni ln nh mt ngnh cng nghip mi v

mang li mt s thnh tu nht nh. Mt trong nhng loi rong c nhiu tnh

nng u vit v ang c trng rt ph bin nc ta, l rong sn.

Rong sn (Kappaphycus alvarezii) l loi rong mi c tc gi Hunh Quang

Nng Phn vin khoa hc vt liu Nha Trang du nhp v trng Vit Nam trong

vi nm gn y. Trong rong sn c rt nhiu khong cht qu nh I, P, Zn v

c bit l carrageenan mt loi polysaccharid c rt nhiu ng dng trong dc

phm, y hc, cng ngh thc phm Rong sn l mt loi thc phm b sung cho

con ngi nhiu khong cht vi lng cng mt s axit amin cn thit v nhiu

vitamin quan trng nh vitamin A, C, B12,...

Bn cnh gi tr dinh dng t qu du ty cng khng km phn quan

trng. Tp ch Cc nhn t sinh hc ca H Lan ng kt qu nghin cu cho thy

qu du ty l mt th qu c bit c li cho sc khe con ngi. Loi qu ny

cha nhiu cht b hn c c chua, qu kiwi, hay hoa l xanh, nhng loi thc

phm ni ting c gi tr dinh dng cao, c nhiu ngi a dng. Gi tr ln

nht ca qu du ty l tc dng cha bnh m ngi ta khng tm thy trong bt k

loi thc phm no khc. Trong qu du ty c cha cc cht bo v, chng xy ha

nhiu gp 10 ln qu c chua.

Tuy vy, vic nghin cu ng dng rong sn v qu du ty trong lnh vc nc

gii kht nc ta vn cn rt hn ch.

Do vy ti t vn Th nghim ch bin nc ung hn hp t nguyn

liu rong sn v du ty vi mong mun lm a dng cc sn phm ch bin t

rong sn ng thi to ra sn phm mi c gi tr v dinh dng v p ng c

tnh tin dng theo nhu cu th hiu ca ngi tiu dng.

more.edu.vn

- 2 -

Ni dung ca ti bao gm:

1. Tm hiu, phn tch thnh phn nguyn liu chnh v ph gia. Gi tr dinh

dng ca sn phm.

2. Nghin cu phng php x l rong.

3. Xc nh cng thc phi ch.

4. Chn bao b thch hp v yu cu k thut.

5. Xc nh ch bi kh, ch thanh trng v bo qun. Tiu chun thnh

phm.

6. xut quy trnh, gi thnh sn phm th nghim.

Bc u lm quen vi cng tc nghin cu nhm vn dng kin thc hc vo

thc hnh. Do thi gian, kin thc v kinh nghim c hn nn n khng trnh

khi nhng thiu st. Rt mong nhn c s gp ca qu thy c v cc bn

n ca em c hon thin hn.

more.edu.vn

- 3 -

CHNG 1

TNG QUAN

1.1. TM HIU V NC UNG NG CHAI

1.1.1. Gii thiu v hp nc ung.

Nc c vai tr quan trng trong c th chng ta, nc chim khong 60-70%

trng lng c th, trong khong 50% cha trong cc t bo, 20% ha tan trong

mu v dch ngoi t bo. Nc lm nhim v mi gii trong qu trnh trao i cht

trong v ngoi t bo. Cc cht dinh dng phi thng qua nc trong mu v trong

dch bch huyt i vo t bo ca cc m, mt khc cc cht cn b thi ra trong

qu trnh trao i cht phi thng qua nc mi ti c c quan bi tit v thi ra

ngoi.

Nc ung gii kht c mt vai tr quan trng trong cuc sng hin nay, c bit

l trong mi trng lm vic cng nghip, n khng ch l ngun cung cp nc

mt cch tin dng m cn l ngun cung cp mui khong, vitaminVi s phi

ch v b sung mt s thnh phn c gi tr dinh dng, to iu kin tt cho tiu

ha v c li cho sc khe cng vi s tin li, nc ung gii kht s l s la

chn ca nhiu ngi tiu dng.

Ty theo ngun nguyn liu v phng php sn xut, ngi ta chia nc gii

kht thnh nhng loi khc nhau song ni chung th bao gm 4 nhm chnh:

* Nc gii kht c gas (CO2): l loi nc c lm lnh t 12-150C ri em

sc kh CO2 .

* Nc gii kht pha ch: l loi nc ngoi vic c bo ha CO2 cn c

pha ch thm cc thnh phn khc nh nc qu, cc loi ch phm chit xut t

qu, cy, acid thc phm, cht thm, cht mucc cht ny c pha theo mt t

l nht nh. Hin nay trn th trng loi nc ny thng l Coca cola, Pepsi,

nc cam, nc tng lc

more.edu.vn

- 4 -

* Nc gii kht ln men: loi nc ny c chia lm hai loi nh: loi ln

men t qu v loi ln men dch ng, tinh bt. Chng khc nhau v thnh phn v

qu trnh chun b dch ln men nhng ging nhau ch kh CO2 cha trong nc

gii kht u c to ra trong qu trnh ln men dch ng, ln men dch qu, cc

sn phm nh ru vang v ln men t tinh bt nh bia, ru go.

* Nc gii kht cha bnh: l loi nc mui khong t nhin c cha mt s

nguyn t khong c tc dng cha bnh nh I, Br, Co, LiNgoi ra, trong mt s

nc c b sung thm cc vitamin v mt s cc cht dinh dng khc.

Trong tt c cc loi nc ung trn th hin nay mt hng bia chim ti 40%,

cc loi nc gii kht t ng, khng gas, khng hng liu v mu nhn to

ang c a chung. Xu hng thc ung xanh ang pht trin mnh m, cng

vi cc sn phm mi nh: nc yn, nc b ao, nc nha am, tr xanh khng

gp phn lm phong ph thm th trng nc gii kht Vit Nam

more.edu.vn

- 5 -

1.1.2. Cc qu trnh c bn trong sn xut hp nc ung khng gas.

Nguyn liu

Phn loi, ra

X l c hc s b

X l nhit s b Nc, ng, hng liu

Phi ch

Chun b chai (hp) Rt chai (hp)

Bi kh

Ghp kn

Thanh trng

Bo qun

Sn phm

Thuyt minh quy trnh s tng qut:

* Nguyn liu: nguyn liu sn xut hp phi l nguyn liu ti, hoc

nguyn liu x l qua song phi t c cht lng tt, khng b h hng hay

bin cht

Nguyn liu c tip nhn phi c kim tra v s lng v s b v cht lng

c phng php bo qun v ch bin thch hp.

more.edu.vn

- 6 -

* Phn loi v ra nguyn liu:

- Phn loi: mc ch l loi b cc nguyn liu km phm cht, phn chia

nguyn liu ng u v kch thc, hnh dng, mu sc, chnnhm to iu

kin cho cc qu trnh ch bin tip theo c thun li v to cm quan cho sn

phm.

- Ra: nhm mc ch loi b cc tp cht nh ct sn, cc vi sinh vt ra khi b

mt nguyn liu. y l mt trong nhng cng on quan trng ca quy trnh. Yu

cu c bn ca qu trnh ra l nguyn liu sau khi ra phi sch ng thi khng

c dp nt, cc cht dinh dng b tn tht l t nht, thi gian ra phi ngn v

tit kim nc.

* X l c hc s b

Qu trnh ch bin c hc l s dng phng php c hc ch bin s b

nguyn liu, trong qu trnh ny nguyn liu cha b bin i v thnh phn ha hc

m ch thay i v tnh cht vt l.

Ty theo loi nguyn liu, yu cu ch bin m s dng cc phng php x l c

hc khc nhau nh:

- Lm sch: loi b nhng phn khng n c hoc nhng phn c gi tr dinh

dng km ra khi nguyn liu nh: v, ht

- Lm nh nguyn liu: to ra bn thnh phm c kch thc, hnh dng theo yu

cu ph hp vi qu trnh sn xut.

- Phn lc: phn chia nguyn liu thnh nhng thnh phn phc v cho nhng

mc ch khc nhau. V d i vi rau qu thng s dng cc phng php nh

ch, p, lng, lc

* X l nhit s b

Ty theo mc ch v yu cu ca sn phm ang ch bin m ta c th s dng

cc phng php nh: chn, hp, rn, nu, c c

Mc ch ca qu trnh x l nhit s b:

- Lm thay i mt s tnh cht ca nguyn liu theo hng c li cho qu trnh

ch bin v cho sn phm. V d nh qu trnh chn, hp.

more.edu.vn

- 7 -

- Lm tng gi tr dinh dng v to cho sn phm mang nhng c tnh ring

nh gin, mu vng, mi thmV d nh qu trnh rn.

- Bt hot enzyme, lm ngng cc phn ng sinh ha do enzyme gy ra gi

cht lng ca thc phm.

- Gim lng vi sinh vt b mt....

* Chun b dch ng:

ng l mt trong nhng thnh phn ch yu ca nc gii kht. N c tc

dng iu chnh v lm hi ha mi v ca nc ung. Ty thuc vo loi nc gii

kht m lng ng cho vo khc nhau sao cho ph hp.

* Phi ch:

Nguyn liu sau khi x l v dch ng c em phi ch vi nc, ph gia

iu chnh hm lng cht kh, hm lng dinh dng v lm tng kh nng bo

qun ca sn phm.

B sung nc ng: iu chnh hm lng cht kh, to trng thi lng v

mu sc cho sn phm.

B sung acid citric: acid citric va ng vai tr iu chnh ngt va gim ch

thanh trng cho hp.

B sung hng liu: c tc dng lm tng mi v hp dn cho sn phm.

* Rt chai:

- Chun b chai: kim tra xem chai c t yu cu hay khng sau em i ra

v kh trng.

- Rt chai: m bo t l ci nc v khi lng tnh ca sn phm.

* Bi kh:

L qu trnh ui kh ra khi hp trc khi ghp np. Kh y ch yu l

khng kh ln vo trong thc phm khi ch bin, n gy nh hng ti cht lng

sn phm cng nh qu trnh thanh trng sau ny nh: gy oxy ha thc phm, lm

tng p sut bn trong hp.

Bi kh c tc dng:

- Gim p sut trong hp khi thanh trng nhm gim nguy c v hp.

more.edu.vn

- 8 -

- Hn ch s pht trin ca vi sinh vt hiu kh.

- Hn ch qu trnh oxy ha thc phm

* Ghp kn:

L qu trnh quan trng nhm cch ly thc phm vi mi trng khng kh v vi

sinh vt bn ngoi, c tc dng rt quan trng i vi thi gian bo qun v cht

lng thc phm.

* Thanh trng:

L khu rt quan trng trong sn xut hp, n quyt nh n an ton v vi

sinh v cht lng sn phm. Qu trnh thanh trng phi m bo thi gian, nhit

tiu dit ti a vi sinh vt gy hi, vi sinh vt gy h hng nhng khng lm gim

cht lng sn phm.

- Cc loi hp c pH < 4,5 vi khun a nhit khng pht trin c m tnh

chu nhit ca n cng gim nn d b tiu dit khi nng nhit , i vi thc phm

ny ch cn thanh trng nhit < 1000C.

- Cc loi hp pH = 4,5-5 thng c cc vi sinh vt a nng k kh, mun tiu

dit cn nhit 100-1210C.

- Cc loi hp c pH > 5 vi sinh vt pht trin trong mi trng ny u l vi

sinh vt a nng nn cn thanh trng nhit cao 100-1210C.

* Lm ngui:

Sau khi thanh trng sn phm c lm ngui ngay n nhit 35-400C.

* Bo n, kim tra, dn nhn:

Sn phm phi c kim tra sau thi gian bo n nhm loi b nhng hp

khng t tiu chun nh phng, mo sau tin hnh lau chi, dn nhn v bao

gi theo nhng quy nh c th v cui cng ca sn phm xut xng.

1.1.3. Tnh hnh pht trin nc gii kht Vit Nam

Hin nay nc ta c rt nhiu loi sn phm ung khc nhau, cc loi

ung phong ph c v hnh dng ln chng loi. Theo cc chuyn gia nghin cu th

trng th hin nay ung Vit Nam ang rt hp dn vi cc nh u t. S xut

hin ngy cng nhiu cc sn phm cng vi nhu cu ngy cng cao ca ngi tiu

more.edu.vn

- 9 -

dng lm cho cc doanh nghip c s cnh tranh khng nh sn phm cng

nh thng hiu ca mnh.

nng cao cht lng ca sn phm ung, t chc tiu chun ha quc t

ISO ban hnh hng dn cho ngnh ch bin thc phm v ung trong vic

thc hin h thng qun l cht lng theo tiu chun ISO 9001-2000. l tiu

chun ISO 15161.

qun l v nh hng pht trin cho ngnh ny, th tng chnh ph ra

quyt nh s 28/2002/Q-TTg v ph duyt quy hoch tng th ngnh ru-bia-

nc gii kht n nm 2010. Mc tiu xy dng ngnh cng nghip ny thnh mt

trong nhng ngnh cng nghip ch yu.

Trong xu th hi nhp kinh t th gii, vi s gia nhp t chc thng mi th

gii WTO to ra nhiu s bin i ln cho ngnh sn xut ung ca nc ta.

Mc d cn gp nhiu kh khn v trang thit b, c s h tng v sc p ca s

cnh tranh song vi s nng ng v sng to, tc tng trng ton ngnh ru-

bia-nc gii kht ca nc ta t kh cao.

Bng 1.1: Ch tiu sn lng ru-bia-nc gii kht nm 2008

Loi sn phm Nm 2008 (triu lt) Nm 2010 (triu lt)

Ru 1400 1500

Bia 270 300

Nc gii kht 950 1100

1.1.4. H vi sinh vt trong hp rau qu

Rau qu b vi sinh vt nhim vo trong qu trnh vn chuyn v bo qun. Trn

b mt rau qu thng sau khi thu hi nu cha c em i ch bin ngay th

thng b nhim vi sinh, thng thy nhiu loi nm men nh: Saccharomyces vini,

Shizosaccharomyces acidodenoratus, Torulopsis,...cc loi nm mc nh:

Aspergillus, Penicillium, Mucor, Botrytis,... Theo nghin cu ca Modavia th trong

khi vn chuyn, bo qun trung bnh lng vi khun tng 14,8 30,6%, nm men

v nm mc tng 10,2 25,6%. V vy nn bo qun nguyn liu nhit thp.

more.edu.vn

- 10 -

H vi sinh vt trong hp rau qu thng c chia lm 3 nhm:

Nhm 1: vi pH = 3,2 4,6, cc vi sinh vt kh pht trin v khng to cht

c.

Nhm 2: vi pH = 4,6 5,2, bo t c bo tn, ch pht trin v to cht

c khi hp nhim nhiu vi sinh vt (hn 1000 bo t/gam).

Nhm 3: vi pH > 5,2, trong loi hp ny c Clostridium botulimun

(khng nh hn 100 bo t/gam), chng to cht c.

1.1.5. Phng php thanh trng nhit bng nc

Thanh trng bng nhit vi tc nhn l nc v hi nc l phng php thanh

trng ph bin nht trong sn xut hp.

Khi nng nhit ca mi trng ln qu nhit ti thch ca vi sinh vt th

hot ng ca vi sinh vt b chm li. nhit cao protein ca cht nguyn sinh

b ng t lm cho vi sinh vt b cht. Qu trnh ng t ca protein khng thun

nghch nn hot ng ca vi sinh vt khng c phc hi sau khi h nhit.

Phn ln vi sinh vt b tiu dit t = 60-700C, ch c mt s vi sinh vt a nhit

c kh nng pht trin nhit ny. Nm men km chu nhit hn c khi un

nng 50-700C trong 5-15 pht cht. Nha bo ca nm men bn nhng nhit

tiu dit n cng ch cao hn 5-100C, nm men a nng c th chu ng

1000C trong 30 pht. Nm mc bn vng hn nm men mt cht nhng phn ln

cng b tiu dit 70-800C, nha bo ca nm mc chu ti 1000C.

Vi khun a nng tng i bn vi nhit l do cu to ca nguyn sinh cht

c kh nng chu tc dng nhit cao. Nha bo ca vi khun, c bit l vi khun

a nng li cng bn vng i vi nhit, c mt s c th chu c 1300C. Hm

lng nc trong nha bo thp lm cho qu trnh ng t protein kh khn v

dn nhit km ca v nha bo lm cho nha bo chu c nhit cao.

Cc yu t nh hng n qu trnh thanh trng bng nhit

a. Loi v s lng vi sinh vt

hp l mi trng dinh dng tt nht cho s pht trin ca vi sinh vt. Cc

loi vi sinh vt pht trin mnh trong cc mi trng c acid hay pH khc nhau.

more.edu.vn

Documents

Thử Nghiệm Chế Biến Nước Uống Hỗn Hợp Từ Nguyên Liệu Rong Sụn Và Dâu Tây - P1