KHOA HOC CONG NGHE
XAC D|I\]H HAIVI LLrqniG a, /3, <5-TaCOPHERDL, /-ORYZAIXIOL V A K H A O S A T H O A T TilMH KHAIMG O X I H O A
CLIA M O T SO D A U C A M GAO O CAIM T H O
Nguyen Trpng TuSn', Nguyen HoM Thuong^
T(^MTAT
Cam gao duoc biet la mot phu pham ciia qua trinh san xuat liia gao. Dau cam co trong cam gao la nguon cung cap cac thanh phan tocopherol va ;.'-oryzanol, la nhung hop chat co boat tinh sinh bye cao. Sau loai dau cam til hat lua cua 6 gidng liia la MTL547, MTL648. OM5451. MTL%0, M'I1J366, MTL856 da dirpc trich ly. Ham lupng cac hirp chat tocopherol va j'-oryzanol duoc xac djnh bang HPLC-UV-Vis va ho^t Unh khang oxi hoa ciia ddu cam cung duoc khao sal. Ket qua cho thay rang bam lirong diu cam chiem khoang tu 18.89- 26,68%, ham linmg cua cac thanh phan' a-locopherol tu 0.7-266.97pg/g. /i-tocopherol tir 901,20-2136,28 Mg/g, (5-tocopheruI tir 42,55-121,23 pg/g va ;'-or\'zanoI tu 2152,10-2765,94 yg/g. Ngo^i ra, dau cam chi^t tir 6 mdu nguyen lieu tren cung the bien hoat tinh khang oxi hoa kha tdt voi gia fri IC,, ldn lupt la: 198.92, 205,76,196.38, 205,42, 227.57 va 385.64 pg/mL
TIT khod: Cam gao, a, p. ^-tocopherol. y-or\'zanol. DPPH.
1.GI0IT11IEU
Viet Nam la mot trong nhimg qudc gia xuat khau gao dung dftu th^ gidi. Theo Tdng cue Thdng ke, san xuat ii6ng nghiep nam 2018 phat trien dn dinh va cd muc tang trudng klia. San luong luong thuc co hat ciia ca nude dat 48.9 hieu tan. trong do san luong liia dat 44 hieu tin, fang 1.240,3 nghin tjin. Dien tich gieo hdng liia nam 2018 dat 7.570,4 nghin ha (Nien giiini Thdng ke, 2018). Nganh cong nghiep itia gao v^n tiep tuc phat trien, vi vay nhimg san pham phu sau qua hmh san xuSt liia gao cung se tiep tiic duoc tao ra. Cam gao sau khi dugc trich ly ddu, phan cam trich dau lam nguyen heu dau vao cho thuc an chan nii6i, c6n phan dau cd the dugc sii dung cho hnh vyc diroc phSm, my pham va thuc pham.
Cam gao chidm khoang 8% ve khdi Iuong cua hat Ilia (Sarmento et al, 2006). Trong cam gao chtia nhieu vitamm va cac nguyen td vi luong, dac biet, chua khoang 12-15% protein, 9.8-10% cellulose, 12-24%
dau (Huang et al, 2013). Nghien cuu ciia Cicero va cong SIT cho tlieiy, trong d^u cam gao chtia nhidu acid beo bat bao hoa (acid oleic 38,4%. acid hnoleic 34.4%
va n-linoleic acid 2,2%), cac acid beo hao hoa (acid pahniUc 21,5%, acid steric 2,9%) (Cicero etai, 2005).
Dau cam gao cung chua nipt luong ldn cac chat khdng xa phong hoa Gen den 5%). trong do cac sterol (/^sitosterol, campesterol va stigmasterol) chiem 43%,
cac triterpen alcohol (24-inethylenecycloartanol.
cycloartanol va cycloartenol) chidm 28%, 4-methyl sterol chiem khoang 10%. cac thanh ph^n kem phftn cue khac (squalene, tocopherol, tocotrienol) chidm 19% (Cicero et al, 2005). DSu cam gao con chua 0,1- 0,14% vitanun E, 0,9-2,9% oryzanol. Cic thanh phan trong dau cam gao la nhung chat khang oxi lot thong qua viec loai bd cac gdc tu do. Nhimg thanh phdn kh6ng xa phong hoa co trong dau cam gao nhu phytosterol. oryzanol, tocotrienol giiip lam giam LDL-cholesteroI (low density hpoprotein- cholesterol). Cac tocotrienol va oryzanol co tac dung nhu cac tac nhan chdng lai tia UV, giiip phat tri^n tdc va ngan lao hoa da (Nagendra Prasad et al, 2011).
Ngoai ra, chiing cdn c6 tidm nang trong viec kidm soat su bai tiet ciia tuyen yen, irc che su bai ti^t acid gastric, khang oxi hoa va chdng su kdt tap tieu cdu (Cicero e^ a/., 2005).
Do c6 nhidu iing dung quan trong cua ddu cam gao, nen viec nghien ciiu 'Xac dinh ham lupng a, fi, S-tocopherol y-oryzanol va khao sat hoat tinh khang oxi hod cua mot sd cam gao"la thuc su can thiet. Vi vay, nghien cuu nay nhdm muc dich xac dinh ham luong cac thanh phdn co hoat tinh smh hoc trong ddu cam gao tu cac giong liia gao khac nhau b Can Tho va kha nang khang oxi hoa cua mgt sd mau dau cam gao. nham tan dung nguon phu pham cam gao tao ra cac san pham cd ich cho con nguoi.
Khoa Khoa hoc Tu nhien. Tmimg Dai iioc Can Tho
».A,,i^ k.^uicD \/A PHAT TRIEN N O N G THON - KY 1 + 2 - THANG 2/2020 127
2. NGUYBI LEU VA PHUDNG PHAP HOKti CUU 2.1. Nguyen li^u va thi^t bi
- Nguyen heu: hat lua (thoc) tir cac gi6ng liia Orj'za sativa L var hidica gdm MTL547. MTL648.
.MTL560. MTL566. MTL856 va OM5451 OITL midn Tay ltia. OM: 0 M6n) dugc chgn loc va cung cdp tu Vien Nghien cuu va Phat trien ddng bdng ?6ng Cim Long, Tnrong Dat hoc Can Tho. Lua (thdc) ciia cac gidng Ilia tren dugc thu Idy true tiep trong qua tnnh thu hoach, sau do dirge chuyen den phong thi nghiem de tien hanh nghien cuu.
Thiet bi: he thdng HPLC-U\^\'is (Thermo Scientific) voi cot sdc k\- ODS H\TERSIL Cl8 (5 pm, 150 X 4,6 mm), may quang pho L"\'-\'is Jen\s"ay 6800, be sieu am Transsomc T570 va cac thiet bi khac.
- H6a chat: ethanol (Merck. 99.9%). methanol (Merck, 99,9%). acetonitrile (Merck. 99,9%). DPPH hay 2,2-diphenyl-l-picrylhydrazyl (Sigma-aldrich) va cac hda chat khac.
2.2. Phuong phap nghien a i u
- Trich ly ddu cam tu mdu nguyen heu. hat Itia duoc tidn hanh xay. xat va sang qua ray 0.5 mm de loai bd trau thu Idy cam th6. Six dung cam th6 vua thu dugc de thuc hien chiet dau cam theo quy trinh cua Tabaraki va Nateghi (2011) c6 chinh siia nhu sau:
Mdu cam dugc say b lOQfC trong 15 phiiL Lay 0,5 g mau cam tho sau say, chidt voi 10 mL ethanol trong 45 phtit b 50T sii diing sdng sieu am dd tang hieu qua chief voi tan sd 35 kHz. Ly tam mau df 3000 vong/phiit trong 10 phiiL Igc dd thu lay dich Igc. sau do tidp tuc them dung m6i tuong ung va hen hanh ly tam 2 lan nua. Loai bd dtmg ni6i bang cach dk bay hoi, thu duoc ddu cam. Can va xac dinh kh6i lugng.
Ddi vol mdi mdu cam, thuc hien trich ly ba Idn lap lai vol nhung mau khac nhau trong cimg mpt dieu kien de so sanh.
- Xay dung dirdng chuan a. 0. ^-tocopherol va; - oryzanoh Can chmh xac 10 mg chdt chudn. cho vao binh dinh muc 10 niL. dinh muc den vach bang he dung m6i acetonitrile: methanol (7:3). Tiep tuc pha loang den cac ndng dp khac nhau 50. 100, 150. 200.
250 pg/niL cua a. p. (^tocopherol) va 150. 2rH"'. 250.
300, 350 pg/mL ciia j-oryzanol. Tien hanh phan nch bdng ky thuat HPLC-LA"-\is voi pha dgng la he dung m6i acetonitnle: methanol (7:3). tdc do dong 1.7 mL/phut. the tich mau tiem 10 pL. dau do LV-Vis dat d buoc song 280 nm. \a\ mdi chdt chuan. tien hanh thuc hien phan tich ba lan lap lai.
- Xic dinh ham luong a. p, d-tixvpherol is y- on-zanol Mau dau cam frich ly a tren duoc hoa tan lai trong 2 mL he dung moi acetonitnle: methanol (7:3). sir dung song sieu am co tan so 35 kHz. trong 5 phiit de h6 trg qua trinh hoa tan. sau do Igc qua mang loc 0.45 pm va tien hanh phan tich bdng ky thuat HPLC-l'\"-\"is VOI cimg didu kien khi xay dung duong chuan a. p. .Mocopherot la }-oiyzanol. Xac dmh cac hgp chat dua tren su phu hgp ihdi gian Imi L-ua chiing voi cac chat chudn va ham lugng ciia chting dugc tinh bdng cach dua vao phuong hinh duong chudn tuyen tinh sir dung dien tich peak cue dai ciia cac chat. Tidn hanh phan tich 3 lan lap lai voi mdt mdu ddu cam.
- Khao sat kha n^ng khang oxi boa (kha nang loai bo gdc tu do DPPH): Kha nang loai bd gdc hr do DPPH ciia cac mdu ddu cam dum: thuc hien theo Sharma et al. (2009): hdn hop phan ung gdm 40 pL DPPH (1000 pg/mL) va 960 pL mdu thu nghiem la dung dich ddu cam voi cdc nong do khac nhau, dugt:
u d didu kien tdi. nhidt dp 30"C, trong thdi gian 30 phtit. Sau d6. ddn hanh xac dmh do hap thu quang phd cr budc sdng 517 nm. D6i chung duong sir dung la vitamin C voi day nong dp tu 1-7 pg/mL Thu nghiem voi moi mau ddu cam duoc lap lai ba Ian, Kdt qua hoat tinh khang oxi hoa ciia cac mau thu diroc bieu dien bdng gia tri IC^j, (The half maximal uihibitory concentration).
- Xu ly sd liemkkt qua cac thir nghiem dugc xu ly bdng phdn mem Excel 2013 va thuc hien phan tich thdng ke bdng cac phep phan tich tren phdn mdm SPSS 16.0.
S.KETQUANGHeyCUU
3.1. K^t qua trinh ly dau cam to mdu nguygn Heu Ket qua phan tram ham luong dau cam trich Iv duoc. duac tinh dua tren khoi Iuong cam tho sau khi say ciia cac gidng liia dugc trmh bay trong bang 1.
Ket qua cho thay ham luong dau cam trich ly dugc tir 6 mau cam gao nam trong khoang 18 89- 26.68%. Trong dd. gidng liia OM,5451 cho ham b o n g ddu cao nhat chidm 26.68±0.32 A , giong lua MTI fiis cho ham luong thap nhat chiem l<-<89~fn'>0' T,- , , . ". - , , , ' - ^ •^^•^ n a m lugng dau cam tnch ly duoc co vj \;^^^. j^-. . . nghia thdng ke. Dieu nay the hien rang cac gidn 1 • khac nhau se cho ham luong dau cam <.^ i .
12 NONG NGHIEP VA PH*^ ^^'^^^ NONG THON - KY 1+ 2 - THANG 2/2020
KHOA HOC CONG NGHE
' Mau cam Ham lirong ddu (%)
Bang 1. Ham lupng dau cam trich ly dupc (56) MTL547
24,79+0,29*
MTL648 OM5451 MTL560 18,89±0,13' 1 26,6«±0,32 , 25.43±0.31''
MTL565 23,39+0,21'
MTLS.Si;
22.77±U.10' Ghi chu: Cac gia tri the hien gia tri trung binh ± dp lech chuan: cac gia tii d cung mdt hang dupc theo s boi chd cai khde nhau thi khac biet d muc y nghia 5%quaphep thuDuncan.
Nghien cuu ctia Noppawat et al., (2015) tren 3 giong lua gao cua Thai Lan la CBIR (Chiang Mai black rice), SBrR (Suphanburi-1 brown rice) va MRR (Mali red rice). Kdt qua nay cho thdy ham lugng ddu cam trich ly tir cac gidng ltia CBIR, SBrR va MRR thap hon so vdi nghien cuu voi cac gidng liia thu mua cr Cdn Tho. Su khac biel nay c6 the do ngudn gdc gidng Ilia gao, vi tri dia ly trong trgt. Mat khac, cac mdu Ilia thu mua dugc trich ly dau cam ngay sau khi thu hoach va duoc sdy kh6 d 100"C Idm cho ham lugng nude hong cac mau cam gao bi mat di nhieu hon, vi the lam gia tang hieu sudt trich ly ddu cam.
Ngoai ra, viec khac nhau trong sir dung dung m6i trich ly cung anh hudng ddn hieu suat thu hdi san pham dau cam. Dung moi ethanol la dung in6i phan cue manh hon dung iii6i hexane hay dung iiioi CO2 long sieu tdi han (dung m6i kh6ng phan cue), da gdp phan lam tang them ham lugng ddu cam trich ly
duoc, do nhieu thanh phdn phan cue khac cd th^ hda tan trong dung m6i ethanol. ma khong the hoa lan trong cac dung moi hexane hay COj Idng.
Tir cac ket qua dat dugc, budc ddu cd the nhan dinh cdc gidng liia dugc khao sat cd chua ham lugng ddu cam kha cao va day se la ngudn phu pham cd gia tn dinh duong dang ke.
3.2. K^t qua xay d\mg dudng chudn a, p, 6- tocopherol va ^--oryzanol
Cac dung dich chuan gdc ban ddu dugc phan tich bdng ky thuat HPLC-UV-Vis, phuong tinnh tuydn tinh dugc tinh loan cho cac chat chuan «, /?, S- tocophero! va ;'-oryzanol thong qua dien tich peak circ dai va ndng do dung dich chuan. Phuong hinh hdi quy tuyen tinh ciia cac chat chuan dugc thd hien trong bang 2.
Bang 2. Phirong trinh hdi quy tuy^n tinh ciia a, 6,6-tocopherol vd K-oryzanol Chat chuan
ra-Tocoplierol
^-Tocopherol
<i>-Tocopherol j'-OiTzanol
Phuong trinh hdi quy tuydn tinh V = 16776X + 9471,5
y = 346,24x - 2656 v = n 8 2 4 x - 1 2 6 0 7 y-57092x-129220
He so tuong quan (R-) 0.9998 0,9996 0,9998 0,9994 K-nplicrol
5 4faO
;' Orvzcini)!
RT. 0 35S
Hinh 1. Sdc ky dd phan tich cac chuan thanh phan a, p, 6-tocopherol va y-oryzanol bdng HPLC Ham lugng ciia cac thanh phan a, P, 5 - tocopherol va y-oryzanol cd trong mau ddu cam tuong tmg, dugc the hien trong bang 3.
3.3. K^t qua xac dinh ham lirong a, tocopherol va j'-oryzanol trong miu dau cam
P, d-
- u i c D \/A PHAT TPIEN N O N G THON - KY 1 + 2 - THANG 2/2020 129
Bang 3. Ham hjpng c^c a, 6, 6-tocopherol vA y-oryzanol c6 trong ddu c6m
MTL648
Ham lupng (yg/g) a-Tocopherol
185,12±17,03'"
^Tocopherol 3635.14+39,63' 4839,82+631.23'''
(i-Tocopherol 238.04+37.31"
302,78+65.31''
..-On'zanol 412,26' 9743.53+' 1464S.11±701,35'' 6007.39±159,33' 215,61+26,56"
MTL560 292,53+3.36' 3898,63+73,91' 3,93+24,12'
S0li.\37±121ji4;^
"^125l43±422.93"
9142,53+2096.68'' 10379.13+836,99'"
MTL856 549,82+36,56'' 6067,63±732.19' 532,52±18,58'' 11525,42+1163,27' Chi chii: cac 0a tii the hien gia tn trung binh ± do lech chuan: cac gia tri d cimg nidt cot duoi' tlieo sau bdi mdt hay nhieu chircai khac nhau thi khac biet dm dry nghia 5% qua phep thuDuncan.
8065.27-14648,11 pg/g dau cam Ki-l Qua ve ham D§u cam duoc trich ly tir 6 mau hat liia khac
nhau cho keit qua ham luong tung thanh phan cung khac nhau ro ret. Trong cac m^u d6u cam, thanh phan y-oryzanol chiem ti le cao nhat so vol cac thanh phan con lai, mau liia MTL648 co ham lupng •/- oryzanol (14648,11 pg/^ cao nhM trong cac mau dau cam. Giong OM5451 va MTL566 Co ham luong a-locopherol rjit tliSp. Miu liia co ham lirpng a - tocopherol cao nhat la MTL648 (1413,82 pg/g) va miu CO ham luong 6-tocopherol czo nhit la MTL856 (532,53 pg/g). P-Tocopherol cho ti le ham lupng c6 trong diu cam khoang 3635,14-9142,53 pg/g. Nhin cliung, miu diu cam tir hat liia MTL648 cho ham lupng cac thanh phan khao sat cao nhat khi so sanh voi cac man con lai.
Ham luong thanh phan o-tocopherol co trong 6 miu Ilia dao dong vao khoang 2,(^'i-1413,82\ig/g dau
lupng ciia hai thanh phan nay pliii hop v6i TCVN12107:2017 ut him lupng cac thanh phan trong dau cam gao. Doi voi vpi hai thanh phan p- tocopherol va (5-tocopherol cho kel qua vol ham lupng tuong ddi cao hon so vpi TCVN12107:2017.
Ham lupng cao hon nay co the do sir dung dung moi trich ly la ethanol. Trong qua ti'inh trich ly co the xay ra sir trans ester hoa cac hpp chat tocopherols dang ester de tao thanh cac tocopherols dang hr do. Ngoai ra, viec sir dung song sieu am h6 tro qua trinh trich ly cung lam tang kha nang chiet xuat cac thanh phin tocopherols hong cam gao.
Ham lupng cua cac thanh phan u, (3, 5 - tocopherol va y-oryzanol cd trong mau nguyen heu duoc tinh toan so vpi long khdi lupng cam gao thd da say kho cua timg giong liia, ket qua thu dupc tir 6 loai hat Ilia dupc trinh bay trong bang 4.
cam, thanh phin )--oryzanol dao dpng vao khoang
Bang 4. Ham liipng cua cac a, 6, g-tocopherol vi K-oryzanol c6 trong cim ggo Man cam
Ham lupng (pg/g)
a-Tocopherol /i-Tocopherol (^Tocopherol )^Oryzanol Tong MTL547 45.93+4.69' 901.20+5.75' 59.04+9.52° 2414,91+72.99"' 3421,13+52,43'
914.15+121.2' 2765,94+119.66' 4004.00+176,69""
OM5451 0.70±0.06' 1602.60±26.27'' 57.51+6.95" 2152,10+51.8:
MTL560 74.40+0.17' I 991.72+30.23' 104.21+4.99' 2352.97+82,18'"
3812,97+45,57'"
3523.33±53,24' MTL566 3.36±1.3.3'
MTL856 25,16+7,S
2139,28+491.66' 42,53+5,31' 2428,69+205,33'"
1381.29±I63,47' 2623.22+253.57^
'«il3,60±557,2r 4363.23+312,20"' Ghi chu: cac gia ni the Men gia tri tmng binh ± do lech chuan; cac gia Oi d cung mdt cot iti/oc Iheo sa boi mot hay nhiiu chd cai khac nhau thi khac biet d mirc y nghia 5%quaphi^p thd Duncan.
Ham lupng cac hop chit a, p, ^tocopherol va -.- tinh toan. Ket qua cho thiy rang ham luong oryzanol co frong cam gao tho sau khi siy cung dupc tocopherol trong hai gidng liia O.M5451
" MTL566 130 NONG NGHIEP VAPH- '• WON© THON - KY l-^ 2 - THANE
2/2020
KHOA HOC CONG NGHE
thdp va khong co su khac biet, nhung co su khac biet CO y nghia thdng ke so voi cac gidng liia con lai. Ham lugng ^tocopherol cua nhdm gidng liia MTLo47.
MTL648 va MTL560 gan tuong duong nhau va khac biet cd y nghia so voi nhdm gidng lua OM5451 va MTL856 cung nhu giong MTL566. Nhdm gidng liia MTL547, MTL648 va OM5451 cd ham lugng 6- tocopherol tuong duong nhau chi cao hon gidng liia MTL566 nhung thap hon ca 2 gidng lua MTL856 va MTL560 khoang 2 ldn. Ham lugng }'M)ryzanol giua cac gidng liia kha tuong dong, chira the hien ro six khac biet cd y nghia thdng ke. Tong ham luong cua cac thanh phdn chua hong cam gao cua 6 mdu thu nghiem dao dong khoang 342L13-4613.60 pg/g.
Trong dd mau hat liia MTL566 cd ham luong cao nhat la 4613,60 pg/g, tiep den la MTL856 la 4363,23 (ig/g, MT1^48 la 4004,00 pg/g. Cac mau con lai, MTL560, MTL566 vii MTL856 cho ham lugng thap hon.
So sanh voi ket qua nghien cuu cua Pham Canh Em va ctv., 2016 trich ly j'-oryzanol tir ba giong liia Nang Huong, OM2541. IR50404. Voi quy trinh da tdi uu hda, trich ly ddu cam bdng phuong phap hd hg- ciiavi song (dung moi methanol, ti le dung moi/cam gao (wt/wt) la 16. nhiet do 51-55"C va thdi gian 9-10 phtit) cho ket qua ham lugng j'-oiyzanol Idn luot theo thu hr Id 5,97+007; 3,16+0,06 va 4,85+0.08 mg/g cam gao (Pham Canh Em vd ctv., 2016). Kdt qua ham luong trich ly nay cao hon kdt qua nghien cuu cua chiing toi. Su khac nhau nay cd the la do su khac
nhau ve cac giong lua dugt sii dung trong nghien cuu, didu kien canh tac vd qua hinh sinh tdng hgi) cac chdt xay ra hong cac cay liia khac nhau. ciing nhu khac nhau vd phuong phdp va dung mdi trich ly.
Nghien cuu ciia Huang etai, 2011 cho thay, dau cam duoc chidt hr 16 loai liia khac nhau nhuTaikeng 4, Kaohsiung 139. Taikeng 14. Taoyuan 3. Tainan 11.
Tainung71, Tamung-Shien 22, 0S4, Jasmine 85, Basmati 385. Taichung-Shien 10, Long Glutinous, Ch'o-Tzu. Kuroo-Mochi. Hung-No, va Ai-Chueh- Shien-Hung-No chua ham lugng o-tocopherol vao khoang 28,16-207,73 mg/kg. /^-tocopherol 0.92-3,27 mg/kg, (>-tocopherol 0,26-2,72 mg/kg va j'-oryzanol 1811,87-3133.14 mgAg. Khi so sanh voi nghien ciru ctia chiing toi, cd the thay rdng, cac gidng liia dugc chgn lua de nghien cuu cho ham lupng/^-tocopherol va .5-tocopherol cao hon hdn (Huang et al., 2011). Su khac nhau nay cd the do su Idiac nhau vd gidng Ilia va VI tri dia ly. thd nhuong khac nhau. Ngodi ra, su ho tro ciia sdng sieu am cung nhu dung moi ethanol duoc su dung trong qua hinh chiet cd the lam gia tang ham lugng cac thanh phdn trong ddu cam gao hong nghien cuu cua chiing toi so voi nghien cihi hen.
3.4. K^t qua khdo sdt kha n ^ g klidng oxi hda Thu nghiem kha nang khang oxi hda (kha nang loai bd gdc tir do DPPH) cua cac mdu ddu cam dugc the hien d gia tri ICr,,, (pg/mL) cua cac mdu thu hong hang 5.
Mau (llg/mL)
MTL547 198,92+0,39'''
Bang 5. Gia tri IC^n (pg/mL) cOa cac miu diu cam MTL648
205,76±1,30'
OM5451 196,38±1,79'
MTL560 205,42±2,01'"
MTL566 227.57±6,08'
MTL856 385,64+1,89'' Ghi chu: cac gia tii the'hien gia tri tnmg binh + dd lech chuan; cac gia tri d cung mot cot dupc tiieo sau bdi mot hay nhieu chu cai khac nhau thi khac biet & muc y nghia 5% qua phep thu Duncan.
hoa ciia chiing ydu hon Vitamin C (IC^, 4.33+0,02 Ket qua hoat tinh khang oxi hoa cua cac mdu
dau cam cho thay. cdc mau ddu cam gao ddu the hien hoat tinh khang oxi hda kha tdt. Kha nang khang oxi hda Ooai bd goc tu do DPPH) co gia tri IC50 nhd hon (hoat tinh manh hon) ddi voi nhung mdu ddu cam dugc trich ly hr cdc mau Ida MTL547. MTL648, OM5451 va MTL560. Cac mdu nay cho hieu qua cao hon hong viec khir gdc tu do DPPH vdi nong do cd do chenh lech thdp 196.38-205,76 pg/mLva khac biet CO y nghia voi cac mau liia MTL566 va MTL856 cho hieu qua kem hon. Tuy nhien. hieu qua khang oxi
pg/mL) hr 45.6 ddn 89,7 Idn.
Nghien cuu cua Noppawat et al., (2015) tren 3 gidng Ilia gao cua Thai Lan la CBIR, SBrR va MRR, cho thdy kha nang khang 0x1 hda (phuong phdp DPPH) ciia cac mau ddu cam tren vo\ gia hi ICr,,, vao khoang 700-2.460 pg/mL. Ket qua nay deu thap hon so vdi ket qua nghien ciru ciia chiing toi. Hai gidng lua BG400 (white) va LD365 (red) cua Sri Lanka da duoc Dilini Bopihya nghien cuu trich Iy ddu cam bang dung moi hexane, cho hieu qua khang 0x1 hda
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KHOA HOC C6n
DPPH. CO gia ui IC5,, ldn lugt la 0,027+0.007 va 0,025+0.001 mg/niL (Dihm Bopitiya et al., 2014).
Dua tren ket qua nay, cd the thay rdng dau cam duoc chidt tir 6 loai hat liia cua chiing toi cho kha nang lic che gdc tir do DPPH thap hon. Su khac biet nay co the do hong dich chiet hexane co chiia nhidu thdnh phdn khang 0x1 hda tot hon trong dich chidt ethanol.
Ngoai ra dung moi ethanol la dung moi phan cue tdt cd the chiet xuat nhidu hpp chat phan cue can h o kha nang loai bd gdc tu do DPPH lam giam hoat tinh chdng 0x1 hda cua ddu cam.
Nhu vay, 6 mdu hat Ida MTL547, MTL648, MTL560, MTL566, MTL856 va OM5451 cho kdt qua khang oxi hoa DPPH hrong doi hieu qua. Tuy nhien, cdn cd them nhung nghien cuu khac de tun ra phuong phap trich ly duoc ddu cam voi hieu sudt cao hon, ham lugng cac hpp chat co loi cao hon, vdi muc dich ung dung phu pham ciia liia gao, ngudn nguyen Heu ddi dao vao hoat ddng cham soc sue khde cho con ngudi. Tir day, gia h i cua lua gao the gioi ndi chung va Viet Nam ndi neng se duoc nang cao, doi sdng cua ngudi nong dan hdng liia cung se duoc cai thien.
4. KFT LUAN
Bdng viec su dung quy trinh trich ly cd su ho tro ciia sdng sieu am da hich ly dugc dau cam tir 6 mau nguyen lieu Id cac gidng lua MTL547, MTL648.
OM5451, MTL560, MTL566 va MTL856 duoc thu mua tai Can Tho. Kdt qua hich ly dau cam, voi giong lua OM5451 cho ham luong cao nhat la 26.68+0,32%.
Su dung phuong phap phan tich, ky thuat HPLC-UV- Vis, cung da xac dinh dugc ham lugng ciia cac a. /3.
5-tocopherol va y-oiyzanol cd trong cac mdu ddu cam. Tdng ham lugng cac hgp chat cd b'ong mdu nguyen lieu chidm ti Ie ldn luot la vao khoang 3421,13-4613.60 pg/g. Ngoai ra, nghien ciru con khao sat dugc hoat tinh khdng oxi hod Ooai bd gdc tu do DPPH), xac dmh gia hi IC^ ciia ddu cam thu nhan tu 06 mdu Ilia dao dong hr 196,38-385.64 pg/niL.
TAI UEU THAM KHAO
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NONG NGHIEP VA PH/' ' " ' " ^ " " ^ f u o M . t-v i * -?. THAW^
2/2020
KHOA HQC CONG NGHE
DETTERMINA'nON OF a, p, <5-T0C0PHER0L, K»RYZAN0L CONTENT AND ANTIOXIDANT ACnVTIY OF SOME OF RICE BRAN OILS IN CAN THO
Nguyen Trong Tuan, Nguyen Hoai Thuong Summary
Rice bran is known to be a by-product of rice production. Rice bran oil is a nch source of tocopherol and y- oryzanol components, which are highly bioacbve. The six types of nee bran oil from die rice seeds of the six nee varieties. MTL547, MTL648, OM5451. MTL560. MTL566. and MTL856 were extracted. The conient of tocopherol and j'-oryzanol compounds were delemiined by HPLC-L"\'-Vis method and the anboxidant acUvity of rice bran oil was also invesUgated. The results showed thai the content of nee bran uil ranged from 18.89 to 26.68%. the content of the components as a-tocopherol from 0.7 to 266.97 pg/g, /f-tocopherol from 901.20 to 2136.28 pg/g. (^tocopherol from 42.53 to 121.23 pg/g and ;-oryzanol from 2152.10 to 2765.94 pg/g. In addition, tiie rice bran oil extracted from the six raw matenal samples also exhibited quite good antioxidant acUvily with ICj^, values of 198.92. 205.76, 196.38. 205.42, 227.57 and 385.64 pg/niL, respectively.
Keywords: Rice bran, a, li. 6-tocopherol. y-oryzanol. DPPH.
Ngudi phan bi^n: TS. Nguyen Manh Diing Ngdy nhan bdi: 01/11/2019
Ngdy thong qua phan bidn: 02/12/2019 Ngdy duydt dang: 9/12/2019
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