NguySn Thi DuySn va Dig Tgp chi KHOA HQC & CONG NGHE 112(12)/2; 109-113
NGHIEN ClTu XAY D I T N G QUY TRINH PHAN TICH VITAMIN BI TRONG MQT S 6 LOAI GAO VA RAU TREN THIET BI CV"C PHO VA797
Nguyen Thj Duyen, VQ Thj Anh , Nguyin Thj Hdi, Nguyin Thuong Tudn
Trudng Dgi hgc Ndng Ldm - DH Thai Nguyen TOM T A T
Cdc tdc gia da nghien ciru xSy dyng dugc quy trinh phan tich vitamin Bl tren thiit bj Cue pho VA797, trong d6: Vitamin Bl trong cdc mau ggo, rau dugc chiet bdng axit clohydric 0,1N trong dieu kien dun soi cdch thuy, dung djch chiet dugc dieu chinh ve pH = 4-4,5 bang dung djch CHjCOONa. Cdc dilu ki^n tii uu Id: dung djch d§m axetat pH = 6,6; thdi gian syc khi 200s. H? s6 thu hii ciia phucmg phdp trSn cdc mau ggo vd mdu rau dgt tir 80,22 - 93,39%, nSm trong gidi han cho ph6p ciia AOAC. Cdc kit qud phan tich hdm lugng vitamin Bl tren mau ggo thu thap dugc dao dOng tir 0,615 -r 3,420mg/kg; mdu rau tir 0,060 •=- 0,147mg/kg. Cdc thong so nghien cim diu phd hgp vdi TCVN 6910:2001 vl dp chinh xdc ciia phuang ph4p vd kit qud do_.
Tir khod: Vitamin Bi. phuang phdp cue phd. dung djch d^m, h? so thu hdi. mdu ggo. mdu rau...
DAT VAN DE
Vitamin Bl (Vit Bl) cd tan khoa hgc Id thiamin Id mgt trong nhiing hgp chat quan trgng, ddng vai trd thiat yeu trong cdc qud trinh sinh hoa xay ra trong co the sdng. Thieu Vit Bl se gay ra mdt sd bpnh nguy hiem cd tha dan dan tu vong. Cdc logi thyc phdm nhu:
thit, ca, rau xanh ... la ngudn cung cdp Vit Bl ty nhian rat tdt cho co tha [5]. (5 Viet Nam, phuang phdp xac djnh Vit BI chii yau dp dyng cac phuang phdp thu cdng cd do chinh xdc khdng cao, mgt sd phdng thi nghiem Idn sir dung thiet bi sac ky Idng hieu nang cao den huynh quang (HPLC), tuy nhien chi phi phan tich cho mdt mau la tuong ddi cao. Theo nghien ciiu, Vit Bl Id mgt hgp chat cd tinh khir, cd tha phdn tich bdng cdc phuang phdp dipn hod, dac biet Id phuong phdp Vdn - Ampe hod tan tran mdy eye phd . Day Id mdt trong nhirng phuong phdp phan tich huu co nhanh vd dgt dugc dg chinh xdc cao, ngoai ra chi phi cho may mdc thiat bj vd hod chdt phii hgp vdi diau kien ciia cac phdng thi nghiem d Viet Nam [4].
Tel- 0982 892 699: Email: vuthianh4}2&.gmail-com
DOI TUONG VA PHUONG PHAP NGHIEN CUD
* Doi luang nghien cihi: Mgt sd logi gao vd rau dang dugc su dyng cho ngudi tran dia bdn thdnh phd Thai Nguyan
* Ngi dung nghien cuv:
- Xdy dyng quy trinh tdch, chiet Vit Bl trong mpt sd loai ggo vd rau dugc nghian ciiu.
- Lya chgn mgt sd dilu kien tdi uu de phan tich hdm lugng Vit Bl tran thiit bj cue phd VA797.
- Danh gid he sd thu hdi ciia quy trinh phdn tich da xay dyng dugc.
- Ap dung quy trinh da phdn tich Vit Bl trong mgt sd logi ggo va rau.
* Phirang phdp nghien ciru - Phuong phap lay mau:
Mdu gao dugc Idy theo tieu chuan Viet Nam 5451:1991;
Mdu rau dugc lay theo tiau chudn Viet Nam 9016:2011;
- Phuang phdp phan tich Vit B1
Nguyen Thj DuySn vd Dtg Tap chl KHOA HOC & CONG NGHE 12(12)/2: 109-113 Chimng trinh ch^iy mdy C{/t' pho VA 797
phdn lich VU BI [7]
Thdngs6 Chl d$ do Cudng dp d6ng thap nhat Cudng dp ddng cao nhai Di?n eye
Kich thudc gipl Toe dp khudy Thdi gian khuay sau khi cho mau
Thai gian cdn bSng trudc khi qu^l (he
The bat dau The kit thuc Budc nhay ihl
vau cdu
Xung vi phdn (DP) lOOnA 10mA DMR 4 2000rpm 3s 10s -1.5V -LOV 6mV KET QUA NGHIEN CUU v A T H A O L U A N Quy trinh tdch chiet Vit Bl trong gao, rau Dya vdo mgt sd tinh chat ly, hod hgc ciia Vit Bl, chiing tdi xay dyng quy trinh tdch chiet Vit BI trong mdu lau, ggo nhu sau:
D6ng nhat mau Can 5-15g mdu da ding nhdt
100ml HCI O.IN Dun soi each thuv 40-45 phi'it
1
De nguoi, chinh pH=4-4,5 bdng CH3C00Na
i
Djnh muc 250ml Lpc qua giav lpc
- \
Thu djch lpc mau Cyc phd
Khao sat, lua chgn mgt so dieu kien toi uu Chgn nen
Trong nin axit xitric - hidrophotphat khdng xudt hien peak d hai gid trj pH= 5,0 vd
pH=6,0. Peak chi xuat hipn d gid trj pH = 6,6 vdi the dinh peak Ep = -1,44 va cudng d$
ddng Ip = -56nA, tuy nhien peak len bj nhiiu (hinh 1).
Bdng 1. Khdo sdt song cue phd cda VitBI trong cdc nin d^m khde nhau pH
axil xitnc - hidrophotphat
Dem axetal
Dem photphat
Ep (mV)
Ip (nA) Ep (mV) Ip (nA) hp (mV)
Ip (nA) 5,0
-
401 6,0
1,30 521
1,39 167
6,6 1,44 -S6
1,27 i6S
1,24 240 Ghi chu: Ddu (-) the hiin khong xudt hien peak
Determination of Vitamme BI (thiamine)
Hinh I D4m axit xitric - hidrophotphat. pH=6.6
Hinh 2. Dim axeiat. pH=6,6
Nguyen Thj Duy6n vd Dtg Tgp chi KHOA HQC & CONG NGHE ll2(12)/2: 109- 113 Trong nen dpm axetat, xuat hien peak d ca 3
gid trj pH khao sat, peak len deu, can doi (hinh 2). Thi dinh peak (Ep) ndm trong khoang tir -1,19V den - 1,30V. Chiiu cao peak thay ddi theo gid trj pH, tgi khodng pH = 6,6 Ip dgt cao nhdt.
Trong nin dpm photphat, xudt hipn peak d hai gid trj pH khao sat 6,0 va 6,6 peak len bj nhiau. The dinh peak (Ep) ndm trong khodng tiir -I,24V den - 1,39V. Chieu cao peak thay dii theo gid trj pH, tgi khoang pH = 6,6 Ip dgt cao nhdt, tuy nhian peak Ien nhiiu (hinh 3).
•eteimlnatlon of Vltamlne B1 (thiamine) vitamine 01
Hinh 3. Dim photphat.
Tir nhiing nghian ciiu tren, vdi myc dich chgn dugc dung djch nan thich hgp cho quy trinh phdn tich Vit Bl bdng phuang phdp cyc pho vd thao tac pha cha don gian, tiet kiem, chung tdi chpn nen dem axetat cd pH=6,6 la dung djch dem cho cac thi nghiem tiep theo.
Anh hudng cda oxi hoa tan
Chiing tdi tien hanh khdo sdt dnh hudng ciia oxi hda tan dan sdng cyc phd cua Vit Bl d nlng do 0,05mg/l bang cdch sue khi nito vdo phau do. Chiau cao sdng cyc phd dugc do sau cac khoang thdi gian Os, 60s, 90s, 120s, 200s, 300s sue khi. Ket qud dugc tha hien d bdng 2.
Qua bdng 2 ta thdy, d thdi gian syc khi Id 0, 60, 90s cdc peak ciia Vit Bl chua dn djnh do oxi hda tan chua dugc dudi het. Sau 120s sue khi cdc peak xuat hien tuong ddi dn djnh, tuy nhian chiau cao peak khdng dau. Sau 200s, tgi khodng ndng do Vit Bl la 0,05mg/l oxi hda tan khdng cdn dnh hudng den sdng cyc phd cua Vit Bl. Nhu vdy. de ddm bdo trong mgi trudng hgp oxy hda tan dugc dudi het khdng
anh hudng dan phep do, cung nhu tiet kiem thdi gian phan tich chiing tdi chgn 200s Id thdi gian syc khi nio ban dau trong cdc thi nghipm tiap theo.
Bang X Anh hudng ciia oxi hda tan den sdng cue phd l ( s )
L^n I ]p (nA)
L^n2 L^n3
;,
(nA) 0 - - - - 60
90 120 200 300
-512 -365 -340 -331
-520 -564 -340 -338 -342
-392 -339 -336
-365,7 -339,0 -336,3 Chl chii Ddu (-j the hi^n khong xudl hien peak He so thu hoi ciia quy trinh thir nghiem He sd thu hdi ciia quy trinh tran cdc mau thir nghipm dugc the hien qua bdng 3. He sd thu hii ciia phuang phap tren cdc mau ggo vd rau dgt tir 80,22 - 93,39%. Trong dd, trung binh he sd thu hdi ciia mau gao dat 91,91%, mau rau dat 82,84%. Nhu vdy, mdu ggo cho he sd thu hdi cao hon mdu rau 9,07%i. Tuy nhien he thu hdi ciia cac mau dau nam trong gidi hgn cho phep cua AOAC (80 -110%) [6].
Bang 3. He sd thu hdi Vd Bl doi vai cdc mdu ndng sdn thuc phdm
Mdu Gao Khang
dan Ggo Bao
thai Gao Bac
thom m
(g) 10,1732 10,5719 11,0976
m.
(fg) 30 30 30
c„
(mg/kg
)
0,71 0,62 0,84
c„«
(mg/kg
)
3,36 3,27 3,34 Trung binh he sd thu hdi (R ) Rau cai
Rau den Rau lang
12,5890 12,3415 12,4061
30 30 30
0,06 0,08 0,10
2.06 2,03 2,14 Trung b'inh he sd thu hoi (l^ )
R
(%)
89,86 93,39 92,48 91.91 83,93 80.22 84,36 82.84
Nguyen Thj Duyfin vd Dtg Tgp ch( KHOA HQC & CONG NGHE 112(l2)/2: 109-113 Ap dung quy trinh de phan tich m$t so
mau ndng san
Bang 4 Kit qud phdn lich hdm lu\rng Vit Bl trong mdu g(io
Ten mSu H^l g90 nguyan
1 Hfit gao nguyen
2 G^o Bao thai Ggo B.ic thom Gao Nep nuong Ggo Tim Gao 16 thu&ng
PmSu (B) 5,1776 5,4822 10.1732 10,5719 10,0010 9,1221 9,9080
(mg/l) 0,061 0,075 0,029 0,026 0,034 0,031 0,029
H L V I I B l (mg/kB) 2,945 3,420 0,713 0,615 0,847 0,843 0,802 Ket qud thu dugc trong bdng 4 cho thdy, cdc mdu ggo khac nhau cd hdm lugng vit Bl khde nhau, dao dgng tir 0,615-^ 3,420 mg/kg. Trong cdc mdu ggo phan tich, cd 02 mdu hgt ggo nguyan cdn vd cam cd ham lugng cao hon so vdi cdc mdu ggo trang cdn lai va 02 mau cd ham lugng Vit Bl thdp hon so vdi tiau chuan chdt lugng ggo cho phep (0,8 mg/kg) [I], cac mdu ggo cdn lai deu dgt tiau chuan chdt lugng. Kit qud nghien cuu tren hodn todn phii hgp vdi kit qua nghian ciru ciia La Thj Khdnh Loan (2010) [2].
Bang 5. Kit qud phdn tich hdm hrgtng Vu Bl Irong mdu rau
Ten m i u Rau can tay Rau den Rau lang Rau ngot Rau cai Rau cai xanh
P mau (g) 10,2129 12,3415 12,4061 11,1045 12,5890 11,2956
Nong d9 (rag/l) 0,006 0,004 0,005 0,005 0,003 0,005
HL VitBI (mg/kg)
0,147 0,081 0,101 0,113 0,060 0,111 Qua bang 5 ta thay, trong cdc mau rau nghian cuu dau cd chira Vit Bl, cac mdu khac nhau thi CO ham lugng Vit Bl khac nhau, dao dgng tir 0,060^0,147 mg/kg. Kit qua nghian ciru tren phii hgp vdi kit qua da cdng bo ciia Vipn dinh dudng.
KET LUAN VA DE NGH!
K i t luSn
- Dd nghien ciru xdy dyn^ dugc quy trinh tach chiet Vit Bl trong mgt sd logi ndng sdn bdng axit clohydric 0,1N trong dilu kipn dun soi cdch thuy va khao sdt chgn dugc dung djch d^m thich hgp cho phdn tich vit Bl Id dpm axetat, pH =6,6 vdi thdi gian syc khi thich hgp Id 200s.
- Da tiln hdnh danh gia hp sd thu hdi cua phuong phdp tren nen mlu rau vd*mlu g?o dgt 80,22 H- 93,39% va dp dung quy trinh xac djnh Vit Bl trong mgt sd mau ggo vd rau thu thgp tran dja bdn thanh pho Thai Nguyan.
- Cdc thdng so ky thugt, dg chinh xdc diu phii hgp vdi TCVN 6910:2001 va nam trong gidi hgn cho phep ciia AOAC [3],[6].
De nghi
Tilp tyc nghian ciiu khao sat mgt sd dieu kipn vd cac nen mau khac de quy trinh hoan thipn hon.
TAI LIEU THAM KHAO [1]. Bg Nong Nghiep vd Phdt irien nong thon (2000), Tuyen lap liiu chudn thdc ggo cua Vt^t Nam, mgt sd nude vd id chuc qudc le.
[2]. Le Thj Khdnh Loan (2010). So sdnh tdc difng cua mgl sd enzym thuy phdn di xdc dmh hm lugng vitamin b! trong ggo, Vi^n DH md Ha N9L
[3]. Tong cyc do lupng chdt lugng, TCVN 6910:2001, Dg chinh xdc cua phuang phdp vd kit qud do.
[4]. TLT Vong Nghi. Phgm Luan. Trdn Chucmg WMykn{\99Q), Mdt so phuang phdp phdn tich diin hda hi4n dgi, Chuong trinh hgp lac KHKT VIS Nam - Ha Lan.
[5]. Vipn kilm nghipm (1976). Dinh lugng vitamin, Nxb Y hgc, pi80-231
[6], Of!icical Methods of Analysis of AOAC International (1997), Volume I, sixteenth edition, 3"' renvision.
[7], Peter A. bruttel (2008), Voltammetric analpis methods in electroplating, Metrohm Ltd, Herisau, Switzerland.
Nguyin Thj Duyen vd Dtg Tap chi KHOA HOC & CONG NGHE 1 l2(12)/2. 109 - 113
SUMMARY
STUDY ON BUILDING T H E PROCEDURE O F D E T E R M I N I N G VITAMIN Bl IN SOME KINDS O F RICE AND VEGETABLE W I T H C O M P U T R A C E VA797 Nguyen Thi Duyen, Vu Thi Anh*, Nguyen Thi Hal, Nguyen Thuong Tuan
College of Agriculture & Forestry - TNU The authors have studied and successfully built procedure of determining vitamin Bl on computrace VA797, in which: Vitamin Bl in rice and vegetable samples were extracted with hydrochloric acid 0,1 N in water-bath conditions: then the solution was adjusted with CHsCOONa to pH = 4-4.5. The experimental research had showed that the acetate buffer solution (pH = 6.6) and aeration time in 200s were optimal factors for determining vitamin Bl by polarographic method. The recovery coefficient of the method with rice and vegetable samples were from 80.22 to 93.39%, within the limitation allowed by the AOAC. The vitamin Bt content in rice samples ranged from 0.615 ppm to 3.420 ppm and from 0.060 ppm to 0.147 ppm with vegetable samples.
The findings of the research were satified with TCVN 6910:2001 for the accuracy of the method and results.
Key words: Vitamin Bl, polarographic method, buffer solution, recovery factor, rice samples, vegetable samples...
Phdn biin khoa hoc: PGS. TS. Luang Thj Hdng Vdn - Trudng Dgi hgc Ndng Ldm - DH Thdi Nguyen
' Tel- 0982 892 699. Emad vulhianh412rd).smad a
