CHAN NU6l DONG VAT VA CAC VAN DE KHAC
15. Minitab (2000), Minitab Reference Manual. PC Version, Release 13.2. Minitab Inc., State College, PA.
16. Nager R.G., P. Monaghan, R. Griffiths, D.C.
Houston and R. Dawson (1999), Experimental demonstration that offspring sex ratio varies with maternal condition. Proc. Nat. Acad. Sci., USA, 96: 570-573.
17. Nguyen Van B^c, Le Viet Ly, Dinh Cong Tien va Nguyen Ngpc D u o n g (2005), Kha nang sinh trucmg va sinh san ciia ga Tau Vang mien Nam.
Bao cao khoa hpc.
18. Nguyen Van Quyen (2008), Nghien ciiu anh huung cua cac muc nang luong trao doi va dam tho tren sy smh truong phat due va ti If de ciia ga Noi 6 Dong bang song Ciiu Long. Lu$n an ti^n si N6ng nghiep. Truong D^i hpc Can Tho.
19. Nguyen Van Thirong (2004), Cam nang chan nuoi gia sue - gia cam. Tap II, NXB Nong nghiep, trang: 153-169.
20. Pike T.W. and M. Petrie (2005), Maternal body condition and plasma hormones affect offspring sex ratio in peafowl. Anim. Behav., 70: 745-751.
21. Rutstein A.N., P.J.B. Slater and J.A. Graves (2004), Diet quality and resource allocation in the zebra finch. Biol. Lett., 271: S286-S289.
22. Sarah R.P., A.R. Lee, A.B. William and C G . Simon (2011), Maternal stress to partner quality IS linked to adaptive offspring sex ratio adjustment. Behav. Ecol., 22:717-722.
23. Thuman K.A. and S.C. Griffith (2005), Genetic similarity and the nonrandom distribution of paternity in a genetically highly polyandrous shorebird. Anim. Behav., 69: 765-770.
24. Tran Thanh Van, Nguyen Thi Thuy My va Nguyen Van Sinh (2006), Tinh hinh chan nuoi va dac di^m ga H'mong tai cac huyen viing cao nui da tinh Ha Giang. T^p chi Nong nghifp va phat trien n6ng thon, 20:83-85.
CONG NGHE CHE BIEN THIT DA DIEU Tl/Ol
BANG BAO GOI HUT CHAN KHONG 4 2 5 5 / /
Hodng Vdn Ipc'*, Phiing Diec Tien\ Nguyin Quy Khiem\ Tran Thi Mai Phuong^ va Nguyin Thj Hoa' N g a y n h | n b a i b a o : 08/07/2014 - N g a y n h a n b a i p h a n bi$n: 09/09/2014
N g a y d u p e c h a p n h a n d a n g ; 29/09/2014
T O M T A T
De keo dai thoi gian bao q u a n thit tuoi da dieu co the sii d y n g phirong p h a p bao goi hiit chan khong. Bao bi diing cho d o n g goi hiit chan khong la bao bi PA d a m bao to't nha't cac chi tieu ve cam quan va kha nang kim h a m s y phat trien VSVHKTS. P h u o n g p h a p dong goi hiit chan khong co the giir dupc chat lupng thjt da dieu tuoi trong 10 ngay do'i voi bao quiin lanh 0-4''C va 8 gio doi voi bao quan nhi?t dp thirong ma van d a m bao cha't lupng cam quan, hoa ly, cac chi tieu vi sinh vat theo tieu chuan ciia Bo y te'va TCVN. San pha'm thjt da dieu bang cong ngh? che'bie'n hiit chan khong sau 10 ngay bao quan co chat lupng cam quan, thanh phan dinh d u o n g tuong d u o n g voi thit tuoi ban dau; p H dat 6,32;
i T r u n g t a m n g h i e n cim gia cam T h u y P h u o n g - Vien C h a n n u o i .
^Uy Ban Khoa hgc cong n g h ^ va moi t r u o n g ciia Quo'c hpi
3Bp m o n c h e b i e n , bao q u a n san p h a m c h a n nuoi va ATTP - Vi^n C h a n n u o i .
* Tac gia d e lien h?: ThS. H o a n g Van Loe - PGD T r u n g t a m n g h i e n ciiu gia cam Thyy P h u o n g - Tir Liem - Ha Npi. Tel: (04) 38.385.803 / 0912482234; Fax: (04) 38.385.804; Email: [email protected]
KHKT Chan nudi So 2 - 2 0 1 5
15
CHAN NUOI D O N G VAT VA CAC VAN DE KHAC
dO ri dich 7,063%; khong phan iing duong tinh voi H2S va NH3, dam bao cac chi tieu vi sinh v|t theo quyet dinh 46/2007/QD/BYT.
Tit khoa: Thjt dd dieu, bao bi, dong goi chdn khong
ABSTRACT
Processing technology for fresh ostrich meat by vaccum package
Hoang Van Loc, Phung Due Tien, Nguyen Quy Khiem, Tran Thi Mai Phuong and Nguyen Thi Hoa
Using a vaccum packaging method to prolong the preservation time of fresh ostrich meat. The bags used in vaccum packaging were PA bags which ensure the best organoleptic indicators and inhibit the development of the total aerobic microorganisms. The vaccum packaging method might retain meat freshness in 10 days at 0-4'C and in 8 hours at a room temperature still retain organoleptic quality, chemical and physiological criteria, organism criteria following the standard of Ministry of Health and Vietnamese Standard. Ostrich meat products from the vaccum processing technology, after 10 days of storage that has organoleptic quality, nutrient composition similar to the initial fresh meat, pH 6.32;
leakage of fluid 7.063%; no positive reaction with H2S and NH3, ensuring the microbiological criteria by Decision 46/2007/QD/BYT.
Keywords: Ostrich meat, packaging, vacuum package
1. DAT VAN DE
Tren the' gioi, nganh chan nuoi da dieu dupe phat trien a nhieu nuac chau Phi, My, A va Au. Thjt da dieu thupe loai thjt do, co miii vj trung gian giira thit dpng vat an eo va gia cam. Diem noi trpi ve ehat lupng thjt da dieu la ham lupng ma, cholesterol tha'p nhung giau protein. Thit da dieu dupc mpnh danh la thit s^ch cua the'ky XXI.
T?ii Vi^t Nam, da dieu dupc nuoi tai nhieu tinh thanh, cung ca'p thvrc pham chat lupng cao cho tieu dimg. Thjt da dieu co ham lupng dinh duang cao len sau gie't mo 6 gio, pH thit d^it dp 6 thugn lpi cho vi k h u ^ phat trien, khong bao quan dupc lau. Do vay, can xac djnh ky thuat bao quan sau gie't mo dam bao thjt van co dp tuai. Cac tae gia John (2005), Michael va etv (2005) da nghien euu cac phuang phap bao quan a nhi?t dp tha'p, bao quan bang cac hoa cha't khang vi sinh vat, chong oxyhoa... Bao quan I?nh CO the duy tri dp tuoi ciia thit trong 4-lQ
ngay (Marenzi, 1986). Neii ke't hpp bao quan lanh trong bao goi hut chan khong sau 15 ngay thjt van giir dupe dp tuoi nhu ban dau... O Vi^t Nam, van ehua co nghien cuu nao ve bao quan thjt da dieu. Vai m\ic tieu xay dung dupc quy trinh bao quan ehe'bieh thit da dieu tuoi bang phuong phap dong goi hiit ehan khong, dam bao cha't lupng va vp sinh an toan thue phain phii hpp voi dieu ki$n nuoc ta, trong khuon kho de tai KC.07.01/11-15 "Nghien cieu cdc gidi phdp khoa hoc cong nghe phdt triin cdc sdn pham thuang mai tie dd dieu nuoi tai Viet Nam", nham gop phan nang eao gia trj gia tang nganh chan nuoi da dieu.
2. VAT LI5U VA PHU'ONG PHAP NGHIEN Cifu
2.1. V$t li^u nghien cihi - Thjt da dieu tuoi.
- Bao bi la eac tiii PE (Poly Ethylen day 0,02 mm), PA (PoIyAmit day 0,085mm), PEHD
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KHKT Chan nudi So 2 - 2 0 1 5CHAN NU6l DONG VAT VA CAC VAN DE KHAC
(Poly ethylen with high density day 0.0125inm) chuyen dimg dong goi thvrc phain.
2.2. P h u o n g p h a p nghien o h i 2.2.1. Xac djnh bao bi thtch hap
Thjt da dieii dupc cat Ihanh cae miaig nho CO khoi lupng 150-20ag, sau do dua vao 3 loai bao bi PE, PA PEHD va dupe hut chan khong tren may henkebnan 200A ciia Dire.
Theo doi cac chi tieu cam quan (mau sac, mil!, vj, trang thai), pH, dp ri djch,
VSV hie'u khi tong so... tai cac thoi diem 2,3,4,5 ngay, tir do Ivra chpn bao bi bao quan thich hpp.
222. Xac dftih dim kien vd thai gian bdo qudn Sau khi I^ra chpn dupc bao bi thich hpp, tie'n hanh bao quan thit tai cac dieu ki^n nhi$t dp khac nhau. Cong thiic bo tri thi nghiem xac djnh che dp bao quan nhu bang sau.
Nhiltdp
Chedp d<nig goi Dong goi thucmg (CTl) Dong goi chan khong (CT2)
Nhiet dp thuong (25-30"C) Dong goi thudng (CT3) Dong goi chan khong (CT4) Theo doi cac chi tieu cam quan (mau
sac, miii, vj, trang thai), pH, dp ri djeh, VSV hie'u khi tong so'... ciia thjt bao quan a nhiet dp thuang 2 gio mpt Iwi va thjt bao quan 6 0- 4''C 2 ngay mgt lan. Tir cae ke't qua thu dupc lua chpn ehe'dp bao quan thich hpp nha't.
2.3. Phuong phap phan tich 2.3.1. Phdn tich thdnh phdn hoa hqc
Xac djnh Protein theo TCVN 4328-86, Lipid theo TCVN 1526-86, khoang tong so theo TCVN 4327-1993, am tong so theo TCVN 4326-86.
Phan tieh djnh tinh NHs theo nguyen tac: amoniac sinh ra khi hu hong thjt dupc ke't hpp vai axit clohydric, tgo thanh amoni elorua, muoi nay sinh ra lop mil trSng bao quanh mau thir.
Quan sat h i ^ tupng Miic dp phan ung Nguyen li|u tiiupclo^
Kh6ngo6l6pmuniautr3ng. Amtinh(-) Tiroi Co lop mil trang tan nhanh Duong tinh ye'u (+) Kem tuoi Lop mil trang xuai hien sau khi dat mau thii' vai giay, lau tan. Duong tinh vira (++) Uon Ldp mu trang xua^ hien sau khi dat mau thii, lau tan. Duong tinh manh (^-H-) Rai uon
Dinh tinh H2S bang phan ung mau voi chi acetat theo TCVN 3699; 1990, xac djnh pH theo TCVN 4835: 2002 va xac djnh dp ri djch bang luc hiit mao dan cua giay ipc.
- Ti 1? dich thoat ra (%) = 100 x (Pz - Po)/(Pi- Po)
Trong do: Po: khoi lupng giay lpc liic dau; Pi: khoi lupng ciia giay lpc va mau thit;
P2: khoi lupng gia'y lpe sau khi bao goi mau thit dupc de 610°C trong 24 gia.
2.3.2. Ddnh gid chd'i luqitg an todn v$ sinh thifc pham
- Phan tich VSVHKTS theo TCVN 7928:2008 - Phan tich Coliform theo TCVN 6848:2007 - Phan hch E.coli theo TCVN 7924-1:2008 - Phan tich Slaphylococus aureus theo TCVN 4830-1:2005
- Phan tich Clotridiiim perfringens theo TCVN 4991:2005
KHKT Chan nuoi So 2 - 2015
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CHAN NUOI DONG VAT VA CAC VAN BE KHAC
- P h a n lich Samonetia Iheo T C V N 4829:2005 3 . KET Q U A V A T H A O L U A N 2.3.3. Phuong phdp ddnh gid cam quan
Su dyng phuang phap danh gia cho diem thong qua hpi dong deinh gia so sanh chat Iu(?ng cam quan (trgng thai, mau sac, miii, vi) ciia san phaim thit da dieu tuoi trong cac cong thuc nghien cuu. Thang diem diing trong nghien ciiu nay la thang 6 diem.
2.3.4. PhUtmg phdp xit ly soH^u Xir ly so' li?u bang phan mem Microsoft
3.1. Nghien CIJU xac dinh bao b i bao quiin thich htfp
3,1,1. Bieh dot cdm quan
Theo doi stf bieh doi cac chi tieu chat lugrng cua thjt da dieu du(?c bao quan trong cac tui PE, PA, PEHD bang phuong phap hut chan khong. Ke't qua cho thay: Si^ bieh doi cam quan alia thit da dieu du(?c bao quan trong cac bao bi khac nhau theo thoi gian.
Bang 1. Bi^n doi cam quan ci^a thit da dieu bio quan trong cic bao bi theo th6i gian (n=30) 1 ngay 2 n ^ y 3 ngiy 4 ngay Sngjy
Trgng thii PA PE PEHD
5,00"
5,00*' 5,00""
4,44"' 4 , 2 5 * 4,44""
4,31 ••
4,06"' 4,38«'
4,25'^
3,75'»
4,19=' 4 0 6 1
3,941 PA
PE PEHD
5,00»' 5,00*' 5 , 0 0 "
4 4 4 ••
i:9»
4 3 8 " " 4,25 "•
4,19»
3,81 «a 425"'
3,44°' 3,811 PA
PE PEHD
5,00"
5,00"
5,00"
444 «.
i W * 4,44 ••
4,31*
3,81«»
4 , 2 5 1
i i s " * 3,941 3,69» 3,44"
4061 3^a PA
PE PEHD
5 , 0 0 "
5 , 0 0 "
5 , 0 0 "
4,44"^
4,38"'
4,31 ••
3,881 4,19«=
4 1 3 1 3,63°*
4 O 6 1 4,001 3 3 "
Tong diem PA PE PEHD
2 0 , 0 0 "
2 0 , 0 0 "
2 0 , 0 0 "
17,75»
16,75"' 17,63 ••
17,25••
15,631 17,06»'
16,691 1488<»
16,561 15,881 13,ffl"»
15,501 Chi chii: Cdc sd'trung binh trong ciing mot cot cm moi chi tim phdn tich mang chii cdi a,b khdc nhau vd trong
cting mdt hdng mang chii cdi A,B,C,D khde nhau thi khdc nhau co y nghia thdiig led o miic P<0,05.
3.1,2, Bieh dot dQ ri dich
Ke't qua phan tich cam quan cho tha'y trong suot thoi gian bao quan cac chi tieu ve trang thai, mau sac, mui vj dia thit da dieu
giam dan theo thoi gian. Mau sac cua thjt sau 5 ngay bao quan co mau do tham hon do myoglobin khong dugc tie'p xiic voi oxy do dong goi hiit chan khong nen co mau do tia.
74 KHKT Chan Duei So 2 - 2 0 1 5
CHAN NUOI D O N G VAT VA CAC VAN DE KHAC
Cac chi tieu cam quan ciia thit dupc bao quan hiit chan khong trong bao bi PE la kem nha't ve ca 4 chi tieu nghien cuu, be mgt ciia thit sau 5 ngay bao quan da hit dau nhot, bat dau xua't hi^n miii oi, vi hoi nhgt. Trong khi do, thit dupc dong goi trong bao bi PA va PEHD cac tinh cha't cam quan van dam bao tot va khong co sy khac nhau giiia hai cong thuc nay.
Bdng 2. Bien dot dp ri djch ciia thit da dieu theo thoi gian (%) (n=9)
PA PE PEHD
2n^y 3 ngay 4 ngay 5 ngay
2,71** 1,84-* 2,11'^
3,15"* 2,50^^ 3,43«»
4,14^^ 3,13°' 3,73"^
5,10°* 4,22» 4M°- Ke't qua phan tfch dp ri dich cho tha'y tang dan theo thai gian bao quan. Sau 5 ngay bao quan, dp ri dich dgt 4,22-5,10%. Giiia cae logi bao bi cung co sxf khac nhau. Thit dupc bao quan trong tiii PA co dp ri djch eao nha't sau do la tlii PEHD va PE. Dieu nay la do khi hiit chan khong, tiii PA day (0,085mm) nen khi hiit se tgo ra lye ep manh hon len be mgt thjt lam cho nuoc trong te' bao bi ri ra ngoai nhieu hon,
3.1.3. Bieh doi VSVHKTS
Bdng 3. Bien doi so lupng VSVKHTS ciia thjt da dieu theo thai gian (c(u/g)
^ ^ ^ . C o n g thuc Thoi g i a n ^ ^ ^ . , ^
I n g a y 2 ngay 3 ngay 4 ngay 5 ngay
PA 8,64xl0<
1,15 xOT 2,14x10' 2,64x10!
3,55 xlff PE 8,64x10' 2,36x10!
3,05x10!
6,73 xlO>
1,09 xlO>
PEHD 8,6ixl0' 1,50x10!
2,18 xlO>
7,09x10!
3,86 xlO"
Qua 5 ngay bao quan, tong so' VSV hie'u khi tang dan theo thoi gian. Toe dp tang so lupng VSVKHTS doi vdi bao bi PA la chgm nha't, 6 ngay bao quan thu 5 VSVHKTS tang hr 8,64x10^ len 3,55 xlO^
trong khi do doi vdi bao bi PE va PEHD sau 5 ngay da dat lan lupt 1,09 xlO^va 3,86 xlO* vupt qua nguong chp phep ciia Bp Y te.
Nhu vgy bao bi PA cd kha nang giam dupe su phat trien ciia VSVHK tdt nha't trong 3 loai bao bi da sii dung.
3.1.4. Su bieh doi pH
Bang 4. Bien doi pH cua thit cua thit dh dieu theo thoi gian (n=9)
^ ^ ^ ^ o n g thuc T h o i g i a n ^ ^ ^ ^
I n g a y 2 ngay 3 ngay 4 ngay 5 ngay
PA 5,820"
6,453 ••
6,467 •>
6,420*
6,320 ••
PE 5,820"
6,443 «•
6,4731' 6,413 "•
6,4^0••
PEHD 5,820"
6,447»' 6,477 ••
6,527»' 6,483""
Sau 2 ngay bao quan, gia tri pH cua thjt da dieu tang dan tu 5,82 len 6,44-6,45 va khdng tie'p tyc tang trong nhiing ngay bao quan tie'p theo. Khong cd sy khac nhau giira cac logi bao bi bao quan.
Tu cae ke't qua tren cho thay bao bi PA giu dupe tinh chat cam quan va kha nang ldm ham dupe sy phat trieh ciia VSVHKTS tot nhat. Vi vgy, bao bi PA dupe lya ehon cho thi nghidm tie'p theo.
3.2. Nghien cuu xac dinh dieu ki?n va thai gian bao quan thit da dieu
Tie'n hanh bao quan thit da dieu d cac dieu kien bao quan khac nhau: bao quan d nhipt dp thudng hiit chan khdng (CTl); bao quan d nhiet dp thudng khdng hiit chan khong (CT2); bao quan d nhipt dp 0-4"C hiit chan khdng {CT3); bao quan d nhi^t dp 0-4''C
KHKT Chan nudi So 2 - 2 0 1 5
75
CHAN NUOI DONG VAT VA CAC VAN DE KHAC
khong hiit ehan khdng (CT4). Theo doi eae chi tieu cam quan, pH, dp ri dieh, VSVHKTS de dua ra che' dp bao quan thich hop nha't dam bao chat lupng va VSATTP.
3.2,1. Bieh doi cdm quan cua thjt a cdc che' dg bdo qudn khdc nhau
Ta't ea cac chi tieu cam quan eua thjt da dieu d nhi|t dp thudng (30''C) giam ra't
nhanh sau khi gie't md, dac bi$t khi khdng hiit ehan khong. Trong 2 gid dau, chua thay sy khac nhau giiia 2 cong thiic. Tuy nhien, sau 6 gid de d nhipt dp thudng (SD'C) thit khdng ddng gdi da bat dau cd miii di, be mat hoi nhdt, mau sac tdl dan, vj nhgt (tdng diem la 11,69). Dol vdi thit dupe ddng gdi hiit chan khdng, sau khoang 8-10 gid cung bat dau cd hi?n tupng hu hdng tuong tu.
Bang 5. Bien doi cam quan cua thit bdo quin d cac che dp khac nhau theo thdi gian (n=30) I h 2h 4h 6h 8h lOh Trgng thai
Tong di&n c n CT2 c n CT2 c n CI2 c n c r 2 c n CI2
5,00"
5,00"
5,00"
5,00"
5,00"
5,00"
5,00"
5,00"
20,00"
20,00"
444"' 4 3 » ' 4,31»' 4,38 ••
444 B.
4 3 8 ' 438 ••
4,31*
17,57«' 17,45 •>
4 1 3 1 3,561 4,001 3,751 3,691 3,191 4 1 3 1 3,751 15,951 1 4 2 5 1
3,63'»' 2,751*
3,38"' 2,94 •»
3,501 2,811*
3,50°' 3,191*
H O l "
11,691*
3,25 =•
2,50 • 3,25 «•
2,56"' 3,19!- 231 =•
3 3 " • 2,751»
13,075- 10,12*
3,13 «•
2,19*
3,00 n 2,31»
3,06"' 2,25*
3,19 «•
2 3 1 * 1238*
9,06»
Chi chii: Cdc sd'trung binh trong cung mdt cot cua m5i chi tiSu phdn tich mang chit cdi a,b khdc nhau vd trong cdng mdt hdng mang chir cdi A,B,C, khdc nhau thi khdc nhau co y nghm thong kid mvK P<O,05
Khi bao quan d 0-4''C, su hu hong eua thjt xay ra chgm hon. Trong 4 ngay dau, sy bie'n doi cam quan ciia thit dupc bao quan bang 2 cdng thuc khong cd sy khac bi^t. Sau
10 ngay, thit ddng gdi Ihudng bat dau bj nhdt, vj nhgt, cd mui di (tong diem 10,93), trong khi dd, thit da dieu ddng gdi htit chan eac hien tupng nay xay ra sau 12 ngay.
Bang 6. Bien doi cam quan cia th\\. da dieu bio quin 6 cac che dp khac nhau (0-4''C) (n = 30) Ingay 2 ngay 4ngiky 6 ngay 8 ngay 10 ngay 12ngiky Trang thai
Tong diem C I 3 c r 4 C I 3 c r 4 C I 3 c r 4 C I 3 c r 4 C I 3 c r 4
5,00"
5,00"
5,00"
5,00"
5/)0"
5,00"
5,00"
5,00"
20,00"
20,00"
444 ••
4,25"
4 3 8 "
4,31'' 438"' 4>25»' 4,441"
4 3 1 " ' 17,64 ••
17,12"•
4,131 3,961 4 0 0 1 3,961 4,131 3,941 4,061 3,811 16,321 15,671
3,931 3,751 3,981 3 , 5 0 "
3 3 1 " ' 3,56°' 3,88°' 3 , 5 6 "
15,61*
1437 •»
3,55'>' 3,15"
3,691 3 , 3 8 "
3,56 «•
3 , 3 1 "
3,56 •»
3,19"' 1436"' 13,03"
3,19"
2,56"
3,19°' 2,81"
3,31»
2,75*
3,19"' 2,81 «•
1238"' 10,93»
2,56»
2,31»
2,81 «•
2,25"
3,061 2 ^ 5 1 2,811 2,560 1 U 4 1 9,37*
76
KHKT Chan nuoi So 2 - 2 0 1 5CHAN NUOI D Q N G VAT VA CAC VAN BE KHAC
3.2.2. Bieh doi VSVHKTS cua thit a cdc che'dg bao qudn khdc nhau
Bing 7. Bien doi VSVHKTS ciha thjt bdo qudn d cac che dp va thoi gian khac nhau (cfu/g)
^ ^ ^ C o n g t h u c T h W g i a n ^ ^ ^ ^
I h 2h 4h 6h 8h lOh 2 ngay 4 ngay 6 ngay 8 ngay 10 ngay 12 ngay
H u t chan khong (nhi^t dp thuong)
4,55x10' 132x10!
2,73x10=
5,00 xl»i 7,05x10!
1,55x10!
Khong hut chan khong (nhiet dp thucmg)
455x101 2,27x10!
730x10!
9,25x10!
137x10!
337x10!
Hut chan khong ( M i Q 435x101
1,09x10"
1,45x101 2,18x10!
2,27x10!
5,41x10!
1,09x10!
Khong hiit chan khong (0-41O
435x101
2,27x10!
4,23x10!
6,14x10=
736 xOT 1,27x10!
2,10x10!
Ke't qua phan tieh vi sinh vgt cho thay bao quan thit da dieu tuoi bang phuang phap hiit chan khdng ed the kim ham sy phat trien eiia vi sinh vgt td't hon la phuang phap bao quan ddng gdi thudng ca d nhi?t dp thudng va nhipt dp 0-4''C. O nhiet dp thudng, thjt da dieu ddng goi b i n g phuong phap hiit chan khdng cd the bao quan dupc 8h trong khi dd bao quan bang ddng gdi thudng ehi giii dupc 6h (VSHK<10^). Ddi vdi bao quan lanh cd the keo dai 10 ngay (phuong phap ddng gdi hiit chan khdng) so vdi 8 ngay (phuong phap ddng gdi thudng).
3.2.3. Bim doi dg ri dich cua thjt a cdc che' d0 bdo qudn khdc nhau
Dp ri djch cua thjt da dieu tang dan theo thdi gian bao quan, tuy nhien dp ri djch ciia thjt ddng gdi hiit chan khong cao h a n rat nhieu so vdi thjt ddng gdi thudng d ca nhipt dp thudng va nhi?t dp 0-4*^. O nhiet dp thudng sau lOh bao quan, dp ri djeh ciia thit hiit ehan khdng (CTl) la 4,98% trong khi do thit ddng gdi thudng (CT2) la 2,05%. 6 nhi?t dp 0-4°C, thjt dong gdi hiit chan khong (CT3) va thit ddng gdi thudng (CT4) lan lupt la 7 01% va 2,84%. Ke't qua nay la do khi hiit
chan khdng tiii PA se ep sat len be mat thit lam cho nudc trong thit ca thjt bi ri ra ngoai nhanh hem so vdi ddng gdi thudng.
Bing 8. Bien doi dp ri dich cua thit dupc bao quin d cic che dp khac nhau (%) (n=9)
— - ^ C p n g t h u c Thdi g i a n ^ - - - ^
2h 4h 6h 8h lOh 2 ngay 4 ngay 6 ngay 8 ngiy 10 ngay
c n
1 3 3 "
136'>' 1,711 2,81"
4 3 7 "
CT2 1,06"
1,291"
1,431 1,76"
2,05='
era
2,69"
535 ••
5,911 6,251»
7,100
cr4
1,11«"
1,78"
2,021 2,22"
2 3 4 "
Thjt da dieu bao quan trong dieu ki?n thudng tdc dp ri dich nhanh han so vdi khi dupe bao quan trong dieu ki^n lanh. Sau 8h bao quan d dieu ki?n thudng, dp ri djch ciia thit d c n va CT2 lan lupt la 2,81% va 1,76%.
Trong khi dd, d dieu ki^n 0-4''C, miic dp ri dich dol vdi CT3 la 2 ngay (2,67%) va CT4 la 4 ngay (1,78%) cho tha'y khi khi bao quan
KHKT Chan nudi So 2 - 2 0 1 5 77
CHAN NUOI DONG VAT VA CAC VAN DE KHAC thudng do su bieh ddi sinh ly, suih hda, vi
sinh vat..., nen ca'u tnic ciia ca thit bj thay ddi lam lupng nudc trong thit tie't ra nhieu han, thjt bj hu hdng rJianh hon ra't nhieu so vdi bao quan lanh.
khac nhau. Ngay trong 2 gid dau tien, pH cua thjt giam nhanh tu 6,10 xud'ng5^0 (CTl) va 5,93 (CT2), sau dd pH khdng thay doi trong sud't 10 gid bao quan. Trong khi dd, thit dupe bao quan d 0-4''C, pH tang trong giai doan dau, sau 2 ngay bao quan gia trj pH dat 6,35 sau do dn djnh trong suo't qua trinh bao quan.
3.2.4, Bieh doi gid tri pH cua thft a cdc che dg bdo qudn khdc nhau
Gia trj pH ciia thjt da dieu d dieu kien binh thudng va d dieu ki?n Ignh khong ed su
Bang 9. Bien doi pH ciia thit dupc bio quin d cac che dp khac nhau theo thdi gian (n=9)
Cr3 Cr4
Ih 2h 4h 6h 8h lOh 2 ngay 4 ngay 6 ngay 8 ngay 10 ngay
6 , 1 0 "
5,90 »•
5,96i>i 5,96i»' 6,04'"
5,971"
6 , 1 0 "
5 , M i "
5,861"
5,951"
5,961"
5,861"
6 , 1 0 "
6 3 5 1 "
6,321"
6 3 3 1 "
6 3 4 1 "
6 3 3 1 "
6,10'
6 3 6 ' 6,421 6 3 7 ' 6381 6 3 6 '
TiJf ket qua thu dupc qua qua trinh theo ddi chat lupng cam quan va VSVHKTS chting tdi thay thdi gian bao quan thjt da dieu dupc ddng gdi hiit chan khong keo dai deh 8 gid d nhi$t dp thudng va 10 ngay d nhi^t dp 0-4''C, trong khi dd ne'u ddng gdi thudng chi bao quan dupc 6 gid d nhipt dp thudng va 8 ngay d nhi?t dp 0-4''C.
3.2.5. Thdnh phdn dinh dudng, cdc chi tieu vi sinh v^t cua thit sau 10 ngdy bdo qudn
Sau khi lya chpn dupc bao bi va dieu ki?n bao quan (ddng gdi hiit chan khdng nhi?t dp 0- 4''C trong 10 ngay), tieh hanh phan tich eac chi tieu chat lupng eiia thit bao quan sau 10 ngay va thjt tuoi ngay sau khi gie't md.
Bing 10. Chi tieu vi sinh vgt ciia thjt bao gdi hiit chan khong Thit da dieu tuoi sau
khi gjet mo
Thit di di^u bao goi hiit chin khdng 10 ngiy bio quin
Tieu dman 46/2007/QE)-BYT Tongs6'VSVHK
Colifonns E.coti Slaph/iocoats aureus Chtridium perfringens Salmonelia
8,64x101 75
5 15 0 Khong CO
4,64x10=
92 5 96 0 Khongc6
101 10"
10»
10"
w
Khong CO
78
KHKT Chan nuoi So 2 - 2 0 1 5CHAN NUOI DQNG VAT vA CAC VAN DE KHAC
Bang 11, pH, dp ri djch, dinh tinh HaS vi NHs, dinh duang ciia thjt bao g6i hut chan khong Chitieu Thit hroi sau khi giet mo Thjt bao goi hut chan khdng sau 10 ngay bio quin p H
ElQtirich(%) E)irhtinhH2S E)inhtinhNH3 Am tong so Protein (%)
6,05 0 Am tinh Am tinh 75,2 203
6,32 7063 Am tinh Am linh 74,86
20,7
Bing 12. Ch^t lupng cdm quan ciia sin pham thjt bao goi hut chan khong Cimquan Thjt sau khi gjet mo Thit bao goi hiit chan khdng sau 10 ngiy Mau sac Mau do tham dac trung. Mau do tham d|ic trung.
Trgng thai Be m$t kho, khong nhot dinh. dan hoi Be mat hoi nhot dinh, dan hSi kha. mgt dt mjn to't, mgt cat mjn
Miii tanh dgc trung. Nudc luoc thjt trong, vang mo to.
Miiivi Miii tanh dac trung, Nudc lu§c thjt trong, vang
mo to.
Ke't qua cho thay thit da dieu sau 10 ngay bao quan bang phuong hiit chan khdng trong bao bi PA bao quan d nhiet dp 0-4''C giii dupc cha't lupng tot, dam bao tieu ehu&i VSATTP ciia BpYTe.
4. KET LUAN
Bao bi dung cho ddng gdi hiit chan khong la bao bi PA, dam bao td't nha't eac chi tieu ve cam quan va kha nang kim ham sy phat trien VSVHKTS.
Phuang phap ddng gdi hiit chan khdng cd the giir dupc chat lupng thjt da dieu tuoi trong 10 ngay ddi vdi bao quan Ignh 0-4°C va 8h ddi vdi bao q u ^ nhi?t dp thudng ma van dam bao chat lupng cam quan, hda ly, cac chi tieu vi sinh vat theo tieu chuan ciia Bp Y teva TCVN.
San pham thit da dieu sau 10 ngay bao quan cd cha't lupng cam quan, thanh phan
dinh dudng tuong duong vdi thjt tuoi ban dau; pH dat 6,32; dp ri djch 7,063%; khdng phan ung duang tinh vdi H2S va NH3, dam bao cac chi tieu vi sinh vgt theo Quye't djnh so 46/2007/QD-BYT cua Bp Y te ban hanh ngay 2007-12-19 ve vi|e "Quy djnh gidi han tdi da 6 nhiem sinh hpc va hoa hpc trong thuc phain".
Thu nghidm quy trinh bao quan thjt da dieu tuai bang phuong phap ddng gdi hiit ehan khong vdi bao bi PA trong san xua't.
TAI L i f u THAM KHAO
1 John N. S. (2005), Improving the safety of fresh meat, Woodhad Publishing Llmiled, Cambridge England.
2. Marenzi C. (1986), Proper meat storage prevents spoilage, Poultry-Misset 6, Page: 12-15.
3. Michael F.D., John N, S. and A.L. Branen (2005), Antimicrobials in food, Taylor andFrands Group.
KHKT Chan nuoi S62 • 2015
