Tgp chi Khoa hoc - Cong nghe Thuy sdn
KET QUA NGHIEN CL/U DAO TAO SAU DAI HOC
TOI iTU HOA QUA TRINH THUY PHAN PROTEIN TU DAU TOM THE CHAN TRANG {Penaeus vannamei) BANG ALCALASE THEO
PHtTONG PHAP MAT DAP IfNG
OPTIMIZATION OF PROTEIN HYDROLYSIS FROM WHITE SHRIMP HEAD (Penaeus vannamei) BY ALCALASE ADOPTING RESPONSE SURFACE METHODOLOGY
Nguyen Thi ^goc Hoai', Ngo Thi Hoai Durtmg', Ngo Dang Nghia^
Ngay nhan bai 25/12/2012; Ngay phan bien thong qua: 06/5/2013, Ngay duy?i dang, 15/5/2013
roM T A T
Nghien cuu thu hoi protein tit ddu tom bdng enzyme nhdm ndng cao hieu qud su dung nguyen lieu tdm. gdp phdn hgn che thdt thodt tdi nguyen vd gidm thieu 6 nhiem mdi tru&ng Thuc hien toi uu hda qud trinh thuy phdn protein tir ddu tdm bang Alcalase theo phuang phdp mat ddp img, su dung mo hinh eomposit. Tdiuu 3 nhdn td ti le alcalase (0,1-0.5%), nhiet dg thuy phdn (50-70'C), thai gian thuy phdn (2-8 gia). vai hai hdm muc lieu Id hdm lugng protein hda tan vd ndng dg DPPH bl khie Kel qud thu dugc thong so loi uu a nong do Alcalase Id 0,382%, nhi^l dp thiiy phdn la 62''C, th&i gian ihuy phdn la 2 gia. Dich protein thu dugc CO hdm luang protein hoa tan Id 2401,4*0,75mg/l 30ml. khd ndng khu goc tif do 45,7±3,09 pM/mg protein hoa tan Dich protein thu dugc cd chdt lugng Idt, hdm luang protein hoa tan cao, ddc biet Id CO khd ndng chong oxy hda tot, trong dich thuy phdn protein tit ddu torn the chdn trdng co chua hdu het cdc loai axit amin khdng thay the vd chua cac lo^i acid beo khong no nen co the ieng dung vdo cdc muc dich nhu ldm thuc phdm chuc ndng cho nguai
Tit khoa. ddu lom, alcalase, chdng oxy hoa ABSTRACT
Study on recovery of protein from shrimp waste by enzyme aimed to improve the efficiency of using the raw material, to reduce the loss in processing and to limit the environment pollution. The process of hydrolysis of protein from the shrimp head by alcalase enzyme was optimized according to method of response surface, using composite model Three factors chosen were alcalase.subtrate ratio (0.1-0.5%). hydrolysis temperature (50-7ff'C). incubation time (2-4h) with the two response variables that were solube protein concentration and reduced DPPH concentration. The results shown that the optimal area was correspond to alcalase:subtrale ratio of 0.38%, temperature of62''C and incubation time of 2 hours, according to solube protein concentration of 2401 4 ±0 75 mg/130ml hydrolysate and reducing ability of 45 7 ±3 09mM/mg of solube protein The product obtained had good quality, nch of solube protein, especially high antioxidant ability.
Besides, with the essential amino acids and unsaturated fatty acids included, the protein hydrolysate could be used as functional food for human
Key word: shrimp head, alcalase, antioxidant
1. DAT V A N D £ vd phuang phap xir ly md lupng phe ligu cd the Phe lieu tdm Id nhung thanh phan phe ttidi tir chiem 60% khii lupng Idm nguyen lieu D i i vdi t i m cdc ca sd che bien tdm bao gom' dau, vd vd duoi the chan frlng Penaeus vannamei, lupng phe lieu tim. Ngodi ra, cdn cd tdm gay Ihdn. t i m l i t v i sai dau tdm ehiem 28% va vd chiim 9% khoi lupng quy cdch hoge t i m bi bien mdu Tiiy thuic v i o loii tdm nguyen ligu, nhu vdy long luang phe lieu d i u
' NguySn Thj Ngpc Hodi: Ldp Cao hgc Cong ngh^ Sau Ihu hogch 2009 - Tnrdng Dgi hgc Nha Trang ' ThS. Ngd Th| HoSi Duong- Khoa Cfing ngh0 thuc phim - Trudng Dgi hgc Nha Trang ' PGS.TS Ngfl DSng NghTa: Vign C6ng nghg smh hpe va Mfli tudng - Tn/dng Dgi hgc Nha Trang
TRUONG DAI HOC NHA TRANG • 129
Tgp chi Khoa hoc - Cong nghe Thuy sdn So 2/2013
vd t i m the chi4m 37% khii luong torn nguyen lieu.Theo Shahkli et al,1999. p h i lieu tdm chilm 35-40%
so vdi luong nguyen lieu ban d i u cdn trong p h ^ pile ligu thi dau tdm c h i ^ 71,4%, vo chiem 28,6%
vd CO ttie dgt ra v i n d§ Id chung se hu hdng va gay vdn nan ve rrwi tnrdng. Do dd viec giam lupng ptie lieu ttr khdu die bien hoac fim giai [^idp tai sir dung chung chfnh la mgt phirong cacii giup lam tang loi nhugn cho ngdnh thuy san ding Ihdi lam giam 6 nhiem m i l tnrdng.
Trong phe lieu torn co rdt nhidu ttianh phdn co gid tri nhu chitin. protein, astaxanthin vd klioang hiru ca. Tuy nhien, hien nay Itrpng ph§ lieu nay chu yeu dupe sir dung de lam nguyen lieu cho qud trinh san xult chitn. Cac qui Irinh san x u l l chittn dar>g sir dung Id cde qui ttinh hda hoc vd chl tgp tmng tbu hii chihn md ktiing thu hoi cdc thanh phin cd gia tri khac la protein. Do dd, viec nghien dm ldi uu hda qud trinh thiiy phan ddu torn bing enzyme thuang mai Alcalase id can thiet tan dung dupe ngudn protein Idn v i o mpt s i irng dyt>g hiru ich nhu ldm thye phim chirc nang cbo eon r>girdi, gdp phin giam thiiu i nhiem m i l trudng.
Phuang phap quy hoach Ihyc nghiem duoc sir dgng Id phuang phdp tiam dap img bk mat - thiet k i CO cau Irijc tdm (RSM-CCD). Phucmg phdp be m i l d i p img (RSM) la mpt phuong phap thing ke su dung cac dir lieu ^ n h lupng b> c i c ttii nghiem de xdc djnh vd gidi thich nhieu bien phuang trinh.
RSM khim p h i cac m i i quan he giira cac biin giai thich va mpt hay nhilu bien phan img. Ngudi ta gcH Id be mgt ddp img. dgi dien hinh hoc ham muc lieu cua mdt q u i trinh vat ly khdng gian - ttidi gian nglu nhien cho nhirng t)i4n kich thfch. Dac h'nh dupe nghien cuu, hay hdm muc tteu Y Id k i t qua cua sy chuyen d i l bing mgt chirc nang d i p ung ro rang (hay con gpi Id chuc ndng ehuyen dol). Sir Ihay d i i gid tri cua cac bien d i u vao se keo Iheo sy thay doi chirc nang cua hdm mue tteu. Nhirng md hinh thi nghiem aJa mat ddp i>ng luu y d i n sy lya chpn cac biln kich thich, xde djnh cde giai doan quan sat vd tfnh lodn sai so. NhDng biln diu vao Xi (1 = 1, ...,n) cung ducrc gpi Id nhirng bien co sd. Chung dirpc ddc trung bdi mpt loat cae ttidng ttn ttiing k i pj (j = 1 P) (ehue ndng phan phii ddc lap hoac tucmg quan, ca hpi chuan hda...). Trong Irvdng hop chung, nhirng bien )C la nhung biln fhay doi theo khdng gian - thdi gian. Vtec diiu chlnh muc tieu phai dya tren mgt co sd oJa nhirng s i lieu thf nghigm (ttii nghiem vgt iy hay s i hoc) va mpt h i met
d w viec bnh toan cac sai so, nd cho ptiep ta suy ra dupc cac thdng so \ . Sy bieu dien hinh hoc eua chirc nang dap img duoi dang m i t dudng cong.
mpt mat phing hoac mpt mgt ptidng gia lang Arpc gpi Id t>e mat dap img.
II NGUYEN VAT LIEU VA PHlfCnJG PHAP NGHIEN CUTJ
1. Nguyen vat l i ^
Oau l i m ttie t:han trang {Penaeus vannam^
dupc dipn la d i i brong nghien O A I . Oau t i m dupc l l y tir nguyen lieu tdm I h i didn tring die bien lgi Cong ty C i phin Nha Trang Seafoods (F17), Khinh Hda. Nguyen lieu sau l^i l l y duoc vdn chuyin ngay t)lng thiing xdp each nhigt cd bao qudn nude di.
nhiet do < 5°C ve ptidng thi nghiem. Nguydn Hgu bvdc khi sir dyng dupc rua sgeh, d l rao ttong thoi gian 5 phiiL Trong tnrdng hpp chua lam ngay ttil rua sach, dupc bao gdi vd mang di bao quan dong d dieu kign nhigt dp -20''C lai ptidng thi n^iigm Tmng tam Cong nghi sinh hpe va Mii ttvdng.
Che pham enzyme protease Atealase thuong mgi eda hang Novozyme, dupc chiet xull ttr Bacillus lidieniharmis. Nhi#t d i bdo quan l i t nhll la 0*10^;, dilu kign boat ding t i i tru cho enzyme Alcalase Id AF 2,4 L, pH = 8. nhigt d i : 50 •*• 60°C (122 - 140°F). Cdc h i a c h l l sir dyng deu ttiugc k)gi ttnh khiet phan tich (PA).
2. Phmmg phap nghien ci>u
D i u Idm da dupe bdo quan ddng d -20°C, dupe ra ding qua ddm 6 4'*C, b i sung them nude vdi ty 1$
1:1, gia nhiet d 9 0 ^ trong 15 phut sau do Idm ngugi nhanh va t)6 sung enzyme, dupc dua di ttiuy phan, sau khi ttiuy ptian xong, lay mau ra bat hogt enzym a 90°C bwig 10 phuL Tdch l l y rieng phin dich v i ba, phin dich thu dupc mang di ly Idm d 6000 vdng/phut, 4°C, 15 phuL Xdc dinh hdm lupng protein boa lan Irong djch thuy ptian va kha nang khir g i c ty do cua dich thuy phan. Ctitpn dupe d i e dp xir ly nguyen ligu thieh hpp nhd t i i uu hda qud trinh ttiuy phin diu t i m Iheo md hinh Composit.
- Xac dinh ham lirpng protein hda tan bing phircmg phap so m i u : phuang phdp Biuret theo Gomall vdepng sy (1948).
- X ^ ^ n h kha nang ching oxi hoa aJa ( ^ ttiuy phan thu dupc bang test kiem tra kha ndng kiim soat goc tt/ do DPPH theo quy trinh r Ja Huynh v i cpng su (2010).
- Phan Uch ttianh phan acid amin vd acid beo ttieo phuong phap GC (gas chromatography).
Thiet ke thi r»ghiem. Bo tti thi nghiim theo
130 • TRUONG DAI HOC NHA TRANG
Tgp chi Khoa hoc - Cong nghe Thity sdn So 2/2013
phuang phap mgt d i p d-ng (Cenfral Composite Design (CCD)), bao g i m 20 Ihf nghiem. Irong dd co 8 thf nghigm nhin t i . 6 thf nghiem d tam, vd 6 thf nghigm xung quanh tt%ie Kel qua eiia 20 Ihf nghiem nay id gid tti bung binh cda 3 lan ldp. Cac gid tn biin vd gid lii ttung tam cua cdc biin d i e Ilp dupe bieu dien d bang 1.Bdng 1. G i i trj cac y i u t i vd m u ^ y i u to cho phdn thich mgt ddp irng MiFC y l u t6
-1 0 +1
Bien d9C l$p Ti t | enzyme (%)(A)
0,1 0.3 0,5
N l l i ^ dp (°C)(B) 50 60 70
Tiia-i gian (gi6')(C) 2 5 8 Cdc yiu to c i d|nh: Ty ig nude/ nguyen ligu= 1/1. pH t y nhien = 6.5
Ham myc tieu: Hdm lupng protein hda lan (mg protein hda tan/ 130ml djch) (Y,) edng eao cdng tit, tim g i i tri eye dgi eho Y,
N i n g d i DPPH bj khir (|jM/mg protein hda lan) (Y^) cing nhieu edng l i t lim g i i tri cyc dgi eho Y^, A, B, C Id bien ttiyc.
Kit qud thu dupc d Bang 2 dupc xir iy bing phan m i m Design Expert 7.01 (DX7). thu dupc mat d i p irng cOa cie bien doe lgp.
III. K^T QUA N G H I £ N CLPU VA T H A O L U A N
Kit qud thuy phin d i u tom bang Alcalase khi thye hign thi nghidm theo Ihiet ke RSM-CCD dupe the hien d bing 2, kit qua nay dupe nhgp v i o phin mem Design-Expert 7.0 de tten hinh phan tfch thu dupe md hinh hii quy.
Bdng 2. K i t qud thi nghigm theo quy hogch bdc hai composite N
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 IB 19 20
T i l t en.
ryme (%) 0,1 0.5 0,1 0.5 0,1 0,5 0,1 0,5 0,3 0.3 0.3 0.3 0.04 0.56 0.3 0.3 0.3 0.3 0.3 0,3
Nhl^t ttQ (•C) 50 50 70 70 50 50 70 70 60 60 60 60 60 60 46.84 73.16 60 60 60 60
ThM gian (gift)
2 2 2 2 8 8 8 8 5 5 5 5 5 5 5 5 1.05 8,95 5 5
H^m l i r ^ g protein hia tan(mgi130inl djcli tiiiiy phan)
1779.52 2043.053 2160.828 2019.116 1658,287 2061.043 1944.834 2047.932 2412.454 2455.766 2465.075 2611.056 1805.1 2317.842 2135,515 2326,128 2758.93 2736.98 2597.343 2703.524
Nong dp DPPD bj ktii, {pM/mg protein hda tan)
36.77141 40,46754 40,97218 44.2455 36.6765 40.4495 36.6672 39.1086 42,6634 40.8816 42.1588 40.3549 26,3319 34,3788 21,9675 25.78636 36,0591 33.28773 33.7869 31,1505
TRL;ONSDAI HOC NHA TRANG . 131
Tgp chi Khoa hoc - Cong nghe Thuy sdn So 2/2013
1. Anh huang cua nhan to ti le enzyme, nhiet dpva thd'i gian thuy phan d i n ham lu'p'ng protein hda tan
Ham h i l quy:
Him lupng protein hoa tan = 2590.47+113.61A+
76.91 B-88,11 *A*B-338.80A= -233,036^(1) Phuang trinh (1) co p< 0.001 cho Ihay m i hinh tuang thich vdl thye nghiem. Cd R^=96,32% ed nghla l i nd dp dung dung 96,32% Irudng hpp Ihyc nghigm. m i hinh ndy phan anh quan he giija cac bien s i d muc dd tin egy Id 99% vi gid tri p eua
phuong trinh < 0,0001. G i i trj p cCia cdc bien cung nhi p^= 0,0014. Pg= 0,013. P^.B= 0,0162, p cuaA^
B^ < 0,0001. Nhu vdy su ed mdt ciia cdc y i u t i tl ig enzyme A, nhiit dp B, A*B, A', B^ d i u cd y nghTa.
Khi xem xet phdn tich don gidn ban vdi cic bien s i bde mgt vd hai nhung ving mgt luang tdc giiia ehung, kel qua cOng thu dupc cdc phuang trinh hoi qui khdng luang Ihich thye nghigm. VI vdy phuang trinh dupe chip nhdn. Thu dupc d i thj biiu dien sy bien dii hdm lupng protein hda tan theo sy thay dii eua ty Ig enzyme vd nhiet dp thiiy phdn nhu sau:
Ham luoriQ protein hoa lan Contour
Hinh 1. Df) thj bilu difn sir bien doi ham lui^g protein h6a tan theo su thay dSi ciia ti 1^ Alcalase va nhi^t dv thuy phan
Nhin vdo phuang trinh hoi qui (1) ed the thiy ring diy i i mat elliptic paraboioie vdi dfnh quay Idn nen ed g i i tri eye dgi. Vi edc s i ligu thye nghiem sir dung thiet lgp phuang trinh cua mat cong nay eho Ihay rang, niu ting ti Ig enzyme, tang nhiet dp thi ham lupng protein hda tan se lang dan. dgt eye dgi.
sau dd giim xuong, nen chae ehdn mat dap irng ciia (1) se ed diim cyc dgi, do cung chinh la diem loi uu md ehiing la dang quan tam. Nhin vdo gid trj cde h i so cua phuang trinh hoi quy la de nhdn ra met dieu l i he so eua A^. B^ Id idn han so vdi cie he so khae va mang diu dm I h l hien i n h hudng ding ke eiia ehiing den qui trinh thuy phan. He so eiia tf le enzyme v i nhigt dp thiiy phan mang diu duang chirng td viec tdng tl ig enzyme hogc nhiet dd thiiy phin thi hdm luang protein hda tan thu duac Id t^
le thudn. Tuy nhien, dieu ding luu y la he s i cua A'B mang dau dm, dieu ndy co nghTa Id, khi tang hoae giam ding Ihdi ti Ig enzyme v i nhiet dp thuy phdn Ihi tuong t i c giua hai yeu Id ndy ty le nghich vdl ham lupng protein hoa lan tgo thinh Tren eo sd so lieu Ihyc nghiim, khi tang fi Ig enzyme thi ham luang protein hda tan tgo Ihdnh se tang, tuy nhien mue dp tdng cua hdm lupng protein tgo thinh cham din khi tf ie enzyme tang ien eao, he s i ty l i giiJa ham lupng protein hia tan v i ti le enzyme A chi thda man trong khoing ta da ehpn. Khi tang A, B
din mit mirc n i o dd, him lupng protein hda tan se khing tang nira mac du dieu kign thily phin khong thay doi,
Phan mem dd d i nghj cho ta diem t i i uu cho him mye tieu nhu hinh 1, hdm lupng pratein hoa tan cd g i i tri cao nhat d tt l i enzyme Irong khoang 0.25 - 0.4%, nhiet dp thiy phdn trong khoing 58 - 65"C, Ihdi gian Ihiiy phdn khodng 2 gid.
2. Anh huang cua nhan to t i le enzyme, nhigt dg va thd'i gian thiiy phan den kha nang khir goc t y do
Hdm hoi quy:
Khd nang khir goc tu do
DPPH (Y,)= 364.59+21,61A +11.04*B -12,39*C - 10.41*B*C - 42,716^ + 19,62C=(2)
Phuang trinh (2) co p<0,0001 cho thiy m6 hinh tuang thfch vdi thye nghiim. C i R^=93,92%
ed nghTa l i nd i p dung dting 93,92% trudng hpp thye nghiim, md hinh ndy phdn dnh quan hg giira cac biin so d mire dp lin cdy Id 99% vi gid tr| p eiia phuang trinh < 0,0001. Gid trj p eia cdc bien cung nho p^=0,0003. Pg=0.0183, p^= 0.0047. Pg.p=0,0104, p ciia B^<0.0001, C^ =0.0028. Nhu vdy sy ed mgt ciia cic yeu to G le enzyme A. nhiit d i B, thdi gian C, B*C. B^ C^ deu cd y nghTa. Khi xem xet phin Ilch don gian ban vdi eic bien so bde m i l vd hai nhung ving mgt tuang t i c giira chung, kit qud cung thu dupe eic phuong trinh hii quy nhung khing tupng
132 - TRLTONG DAI HOC NHA TRANG
Tgp chi Khoa hoc - Cong nghe Thiiy sdn So 2/2013
ttiich thye nghiem (p>0,05). Vi vdy phuang trinhdupc chip nhgn la phuang frinh (2).
Nhin vao gia In cae he s i eua phuang trinh h i i quy ta d l nhdn ra mgt diiu la he s i ciia B^ Id Idn nhit so vdi c i c h i so khie va mang d i u am Uii hien anh hudng ding ke eiia nhidt do thiiy phdn din qui Irinh thiiy phan. He so eua ty le enzyme v i h i so nhiit d i thiiy phdn cung khd idn vd mang d i u duang ehung td viic lang tt Ig enzyme hoac nhigt dp thuy phan thi kha nang khir gic t y do DPPH- ciia
djch thuy phin Id t^ Id thuin. Trong khi dd, hg so thdi gian ttiiiy phdn id 12,39, mang d i u am chung Id khi keo ddi thdi gian thuy phdn Ihi kha bing bit gdc ty do cua djch thiiy phdn co xu hudng giam. Dieu dang luu y l i hg so ciia B*C mang diu dm. diiu nay eo nghTa la. khi tang hoae giam ding thdi nhiet dd va Ihdi gian thOy phin thi tuong tdc giCra hai yeu td niy ty le nghjch vdi kha nang khu gde ty do ciia dich thiiy phdn. m i hinh bleu diin mii quan he niy Id hinh yen ngya.
Wong do DPPH 111 Miu Contour
Hinh 2. Bh thj bieu dien dnh h i r i n g ciJa ti I f Alcalase va nhift dg Ihiiy phan den n^ng d$ DPFH bi khir cua djcb thiiy ph^n D i thj trin eo dgng y i n ngya, cd miin g i i tn cyc dai, nhin vao d i thj contour v i 3D, d l ding thiy ring, khd ning khu gic ty do eua dich thiiy phan dat g i i tn cao trong khoang tf le enzyme tir 0.3 - 0.4%, nhigt do thuy phdn trang khoang 60 - 65°C. thdi gian Ihiiy phdn id 2 gid.
Kit hpp cd hai hdm myc ttiu ta thu dupe thing so t i i uu Id tt Id enzyme Id 0.382%, nhiet dp Ihiiy phdn Id 62''C, thdi gian thiiy phan Id 2 gid. K i t qui thu duoc d|Ch thiiy phin cd chira ham luang protein hda tan khi cao (18,472g/i), khd ndng khir goc l y do ciia djch Ihiiy phan Ihu dupc l i 45,7pM/mg protein hda tan.
3. K i t qud thdnh p h i n acid amin va acid beo
12 l i n ?
S
MPS M• 1
Hinh 3. T h i n h phan phan t r i m cac axit amin co trong dich thiiy phan a dieu k i | n toi mi
Tir hinh 3 eho thiy. trong d|Ch thiiy phan protein tir d i u t i m the ehdn trang cd chua hau hit cdc logi axit amin thiet yeu. Trong dd, axil glutamic ehiem tylg cao nhit vdi 11,07% so vdi ting cdc axit amin. Tilp dd l i cac axit amin khde cung chiem t / Ig khi cao nhu: leucine (8,28%). axil aspartic (8.19%), lysine (7,89%), alanine (7.11%), proline (6.75%). glycine (6,12%)... Nhu vay, djeh thuy phdn protein ttr d i u t i m the chin tring cd thinh phan dinh dudng khd cao v i dly dii axit amin khdng Ihay the.
TRUONG OAI HOC NHA TRANG • 133
Tgp chi Khoa hoc - Cong nghe Thuy sdn So 2/2013
Hinh 4. Thanh phan phan t r i m ciia cac axii Ket qua trong hinh 4 cho thiy djch thCiy phdn ehua nhieu axit beo khdng no quan trgng l i axit alpha linoleie (ALA) 18:3n-3 (3.37%), axil eicosapentaenoic (EPA) 20.5n-3 (2.27%), axil docosahexaenoic (DHA) 22:6n-3 (2.88%). Ting cic omega 3 id 10 9% v i long cdc omega 6 Id 21.8% eho Ihly ty le hai chat ndy id 1.2. Mac dil hdm lupng add beo frong djch thuy phan khdng cao nhung su cd mgt eiia ede acid beo khdng bao hda cd vai Ird quan trgng.
IV K t T LUAN VA KI^N NGHj
S i n phim protein thu dupe theo che do thiiy phin toi uu cd gid trj dinh dudng vd hoat tinh sinh
1 ^ V
:6 trong dich Ihiiy phan a dhu ki^n titi ini hoc ciia djch thiJy phdn cao, sdn pham Ihu dupc ci chira nhieu ede acid bdo khdng no v i dly du cdc acid amin c i n thiit cho co the, Ihfeh hpp eho viic bi sung vao thye phim con ngudi. Kit q u i Ihl nghi$m toi uu theo m i hinh composite eho dupe ket qud eae thdng so tt l# enzyme, nhiit dp thCiy phdn vd Ihdi gian thiiy phan toi uu Id 0,368%, 62''C v i 2 gid. Sin phim thiiy phdn protein hoa tan ed khd nang ching oxy hda, do dd ein nghiin ciru sdu han khd ndng ehong oxy hda eua djch protein hda lan. CDng cin cd cic nghidn ciru sdu hon ve xdc djnh chieu ddi cua eic dogn pepttd, peptid nio c i khd ndng ching oxy hda, djnh danh peptid.
TAI LIEU THAM KHAO
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2 Gomall, A , G.. Bardawill, C. T., David. M , 1948 Detemunaton of serum proteins by means of the Biuret reaction.
Department of Pathological Chemistiy. Umversity of Toronto, Toronto Canada.
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4. Jens, A„ 1979. DetermiDation ofthe Degree of Hydrolysis of Food Protem Hydrolysates by Tnnitrobenzenesulfonic acid.
Agric food Cheimstry, 6,1256-1262.
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