KHOA HOC CdNG NGH|
/ s o SAlVH s u KHAC BIET VE TIMH CHAT VAT LY, THAIMH PHAIM HOA HOC V A THAIXIH P H A I V CAC CHAT CO HOAT Til\IH SIMH HOC TROI\lG EiAO IVIAM 5AIV XUAT
TU GAO LLTT V A TU THOC CUA GIOIXIG LUA IR 5 0 4 0 4
Ld Nguygn Doan Duy' T6MTAT
Nghidn ciru nhim khao sit kha nang san xuat gao mam tii ihoc va so sinh su khac bidt vd tinh chit vit ly, thanh phan hoa hpc va cac chat c6 hoat tinh sinh hoc so vdi gao mam tir gao luL Ket qua cho thay gao mam tir thoc CO ti le nay mam cao hon, ham Iircmg protein, dudng khii vi vitamin Bl cao hon so voi gao mim tii gao liit Dac biet nghien ciiu cho thay la ham luong cac hop chat fenola tdng sd va ham luong GABA ciia gao mam tii thoc cao hon c6 y nghia so voi gao mam tir gao liit, nhir vay, gao mim tir thoc c6 ham lupng cic chat c6 hoat tinh sinh hoc cao hon, c6 loi ddi voi siic khoe nguoi tieu thu. Cac dac tinh khic nhu d6 trd hd, d6 bdn gel, ham lupng lipit tdng sd, ham lupng hydratcacbon ciia gao mam tir thoc va gao mam tir gJio liit khdng c6 sir khic biet dang ke. Tuy nhien ti le gao nguydn cua gao mam tu th6c th^p hon so vol gao mam tii gao lut Gao mam tir thoc vk tir gao lut cung dam bao dieu kien vi smh, khflng nhidm ailatoxin nen an toan cho nguoi sir dung.
Tli kh6a: Gao mam tu thde, gao mam tii gao lut, GABA ^ -aminobutyric axit), IR 50404.
I.MirOAU
Gao mam li mgt san phlm duoc dinh gii cao vd gii tn dinh duong eung nhu tic dung hd tro sue khoe do bd chua nhieu boat chat chiic nang. Qua trinh nay mam lam thay ddi thanh phan dinh duong va cau tnic cua hat. Hon nua, tinh bgt trong hat sau khi nay mam se dd ding bi thuy phan bdi enzym amylaza tao thinh cic dudng don, giup qua trinh tidu hoa tdt hon (Srisang et al., 2011). Ngoai ra, gao mam con chiia cac chat ho trg cho sire khde nhu toeopheron, tocotrienon va cac hgp chat fenola, giup tang cuong kha nang chdng oxy hda, giup tang cuong kha nang dd khang cua ea the ( Femandez- Orozco et al., 2008). Dac bidt gao mam ed chira cd chua ham lugng y -aminobutyric axit (GABA) tuong ddi cao. GABA l i mgt loai amino axit khong the thidu ddi vdd CO the de dam bao duy tri su boat dgng binh thudng cua nao bg, dac bidt la cic neuron than kinh, li mot chat din truydn than kinh trong nao va tuy sdng eiia cac loai dong vat cd vii. Mgt sd nghidn ciiu gan day cbo thay GABA ddng vai trd quan trong ddi voi siic khde ciia con nguoi nhu giiip ngan chin bdnh Alzheimer (Ito va Ishikawa, 2004), lam giam benh
Bp mon Cong ngh? thyc pham, Khoa Nong nghiep va Sinh hpc img dung, Dai hpc Can Tho
eao huy^t ap (Chung et al., 2009), uc ch^ su tang nhanh eua t^ bio ung tiiu (Ob va Oh, 2004).
Quy trinh san xuat gao m ^ thdng thuong la ngim gao liit va cho nay mam trong di^u kidn tiiicli hgp. Da phan eac nghien ciiu deu di theo hu6ng niy.
Tuy nhidn, gao mam nay mam tu gao lut se co mgts^
nhuge diem nhu l i ti Id nay m ^ th^p va dd bi hu hong do vi sinh vat. Sau khi tach v6 tr^u, mgt s6 ph6i nhu bi tach roi khoi hat gao din den lim giam kha nang nay mam. Thdm vao do, bat gao khdng cAo dugc lop v6 trau bao vd ndn dd hi oxy h6a, ciing nhu chiu tic ddng cua nhi^u phan ung do tic dung ciia enzym. Vi du nhu b thde, hpit se rat it bi bi^n d6i.
Tuy nhidn sau khi tach v6 trau, hpit se bi anh huong eua rat nhidu phan ung v i tao ndn cic axit beo tit do, din den mui hdi cbo san pham, dac bidt n^u qua trinh nay mam keo dii (Warwick etal., 1979). Ngoai ra, qua trinh xay co t h i lam va hat gao, din d^n vific tiep xiic dd dang vdi enzym va vi sinh vat, do d6 gao dd bi hu hong khi qua trmh ngam keo dii.
Mac du nhirng b^t lgi ndu tren, cho din nay, v5n CO it nghidn eiiu d l san xuat gao mam true tilp tit lua. Moongngarm va Saetung (2010) cho th^y ham lugng cic chat ed boat tinb sinh hgc nhu a- toeopheron, y-oryzanon v i dae bidt l i GABA (y • aminobutyric axit) trong gao mam b> gi6ng liia RD-^
eua Thai Lan gia tang mdt each cd y nghia so v6i gao liit nay mam. Ngoii ra, ti Id nay mam eua thde cung 52 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 9/20U
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cao hon va it hu bdng ban so vdi gao lut Tuy nhien, cho din nay b Vidt Nam, vin chua cd cdng trinh nghidn ciiu nao v l vide sin xuat gao mam tir tilde, die bidt li tu gilng lua ed gia tri kinh te thap l i IR 50404. Vl cd kha nang chiu phdn, chong chiu sau ray t6t vi cd ning suat cao ndn giong liia IR50404 duge trlng nhilu 6 nhung vung dat phen b dong bing sdng Cihi long. Die bidt thdi gian sinh trudng ngdn, chi 8^65 ngiy ndn gilng liia nay thich hgp vdi cac viing bi anh hudng lu. Tuy nhidn, pham chat gao thu dugc tir giong liia nay thap, khd tidu thu nen c6 gia thanh thap hon so vdi cae giong lua khac. Vi vay vide nghidn ciiu sin xuat gao mdm tu giong liia niy se gdp phan ning cao gii tri su dung cua nd. Thdm vao dd, vi diy li giong liia thudng trong d viing lu, nen vide sin xuat gao mam true tilp tir liia ma khong qua khiu xay xat se gdp phan giam thieu chi phi say va luu kho cung nhu giam tin that sau thu hoach.
2 . NGUYDI UEU VA PHUDNG PHAP 2.1. Nguydn U|u
Gilng Ilia IR 50404 dugc cung cap bdi Vidn Liia Ding bing sdng Ciru Long.
2.2. Quy tiinh tiii nghidm ting quit
Hai loai doi tugng nghien cihi la thde va gao liit thudc gilng IR 50404.
Thde sau khi duoc lay ve tir Vien Liia DBSCL cung cip se dugc bao quan trong bao bi plastic v i tin trCt 0 4"C ti-ong suot thdi gian tien hanh thi nghiem.
Gao lirt sau khi xay cQng d l tach ldp v6 trau eung dugc bio quin tiong bao bi plastic d 4''C d l dam bao tinh ding nhdt cua nguydn lidu.
Thde ciing nhu gao liit duoc riia trong nuac de loai bo cic tap chdt. Sau dd thde hoac gao Iiit duac ngim trong nude d nhidt do phdng (30 ±2''C ). Tiep tiieo tilde hoic gao lut duoc lam rao nude, gdi trong vai mim vi mang di u trong tii u d nhidt dd 30±2'' C din khi nay mam. Gao mdm duac mang di sdy kho d 50°C din dd dm bio quan <13%. Gao mim sau khi sdy dugc mang di phin tich thanh phin hda hpc va thinh phan cac chdt cd boat tinh sinh hgc. Sau do gao dugc bao quin trong bao bi PE hiit chin khong.
Tdt ca cic thi nghidm dugc bo tri hoan toan ngiu nhidn vi tiiuc hi^n vdi 3 lin lip lai, moi lin sii dung 1000 g mdu gao lirt. Kit qua dugc phan tich tiidng ke ANOVA bing chuong trinh Statgraphie Centurion 15, sii dung phdp kilm dinb LSD d miic y nghia 5%.
2.3. Kbio s i t tiidi gian ngim
Thde hoac gao liit duoc ngam trong nude b nhidt do phdng (30 ± 2*'C) trong thdi gian 24 gid. Cic miu thde hoac gao liit se dugc lay sau mdi gid vi mang di phan tich ham lupng am bang each sdy mau den khoi lugng khdng doi d lOS^C.
2.4. Chudn bi gao mdm a. Chuin hi gao mam tir gao Idt
Gao liit duge ngam trong nude eat d nhidt dp phdng (30 ± 2°C ) trong thdi gian 6 gid. Tiep theo gao dugc lam rao nude va bao gdi trong ldp vii mdng, sau dd ii trong tii ii d nhidt do 30 ± 2°C trong khoang thdi gian 36 gid de nay mam. Gao mim duoc say d nhiet dp 50°C den dp am bao quan <13%.
b. Chuan bigao mam tu thoc
Thoc dugc ngam trong nude cdt d nhidt do phdng (30 ± 2=0 trong tiidi gian 12 gid. Tilp theo, thde duge lam rao nude va bao goi trong ldp vai mdng, sau dd dugc u trong tu u d nhidt dp 30 ± 2''C trong thdi gian 36 gid de nay mim. Thde nay mam dugc say d nhidt dp 50"C den dd am <13%, sau dd duac dem di xay tach ldp vd trdu.
2.5. Xie dinh ti Id niy mdm
Gao lut va thoc sau khi u trong khoang thdi gian 36 gid se dugc xac dinh ti Id nay mam.
Sd h a t nay main
Ti 1^ nay m a m ( % ) = —- r- rxlOO T o n g s o h ^ t a e m u
2.6. Xie djnh cic tinh ehdt vit 1^ cua gao mdm a. Tl le gao nguyin
Trong luong gao nguyen TI le gao nguyen (%) =—'—,—'——'—-. xlOO
Trong lugng lua b. Bd tra ho. xac dinh theo phuang phap ciia IRRI (1996).
c. Bo bin gel xac dmh theo phuang phap phuang phap xac dinh dp ben gel 10 TCN 424-2000 ban hanh theo Quyet dinh 57/2000/QD/BNN- KHCN ngay 23/5/2000.
2.7. Xdc dinh thinh phin hda hoc ciia gao mdm Gao mdm dugc mang di phan tich cac chi tidu gluxit tong so, protein tong so, lipit tong s l , vitamin Bl, ham lugng cic hop chat fenola tong so vi ham lugng GABA va so sinh vdi cac chi tidu tuong tu ciia gao liit. Them vao dd, gao mdm eung dugc phin tich cac chi tieu vi sinh va aflatoxin.
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Phin tich dd dm theo phuong phap say mlu den dd dm khdng doi d 105°C.
Phan tich ham lugng protem tong s l theo TCVN 8125: 2009.
Phan tich ham lugng lipit tong s l theo TCVN 6555:2011.
Phan tich ham luong glucit tong s l theo phuong phap Bertiand.
Phin tich him lugng vitamm Bl tiieo TCVN 5164:2008.
Xac dinh ham lupng aflatoxin theo TCVN 7596:2007
Xac dinh tong so vi sinh vat hieu khi theo TCVN 4884:2005.
Xac dinh E. co/rtiieo TCVN 7924-2:2008.
Xae dinh Salmonella tiieo TCVN 4829:2005.
2.8. Xie dinh cic chdt cd boat tinh sinh hgc ciia gao mdm
a. Xie dinh ham luong y-aminobutyric axit (GABA)
Xie dinh ham lugng GABA theo phuang phap ciia Banchuen va dong tic gia (2010). Cin 0,4 gram miu gao liit nay mdm cho vao ong ly tam (ong 2-5 ml), sau dd bo sung 1,8 ml nude cdt loai ion duge bo sung vio va lac khoang 1,5 gid d nhidt do phong. Sau dd bo sung 0,2 ml ciia 3% axit sulfosalixylic vao va hdn hgp dugc lac diu va ly tam d 4500 vdng trong 10 phiit. Lay 0,05 ml dich noi phia trdn vio ong ly tim mdi, tiiem vao 0,05 ml NaHCOj nong do 100 mM va 0,05 ml dung dieh 4-dimetylaminoazobenzen-4- sulfonyl clont axetonitril 4 mM. Hdn hop dugc u d 70''C tiong 10 phiit de phan ling tao din xuat xiy ra.
Sau khi tao din xuat, miu dugc thdm vao 0,25 ml cdn tuyet doi va 0,25 ml ddm photphat nong do 25 mM (pH 6,8). Sau dd miu duge lpc v i tidm dieh lge vao HPLC (Shimadzu, Nhat Ban) , cot duoc su dung la cot C18 (3,5 pm 4,6x150 mm). Thiet hi HPLC sir dung ddu dd UV-Vis vdi chilu dai budc sdng 465 nm.
Pha dpng l i ddm axetat n l n g dp 25 mM va axetonitril theo ty Id (65:35) vdi toe do bam la 0,5 ml/phut d 55°C. GABA chuan (Merck, Diie) dugc su dung li ehdt chuan d l hieu ehinh.
b. Xie dinh him lupng dc hpp chat fenola tdng sd (Totalienolaic compounds)
Him lugng c i c hgp chat fenola t i n g so dugc xie dinh theo phucmg phip cua Iqbal va dong tic gii (2005) vdi mdt so dilu cbinh. 100 g gao mam dirpc nghiln nhd v i trdn voi 250 mL metanola trong th6i gian 3 gid'. Dich chiet xuat ^.MQC lge qua gidy Ioc Whatman so 1, phdn can cdn lai trdn Igc sd dupe chiet xuat mgt lan niia vdi 100 mL metanola. Dung dich chilt xudt duge b l e hoi trong thiet hi c6 chSn khong. Can khd thu h l i se dugc hda tan trong 10 ml metanola va duge su dung d l xie dinh him lugng cac hgp chat fenola tong. Chdt chudn sir dung li hfin hgp chdt phan ling folin-Cioealteau fenola (Merck, Diic). 0,2 mL chiet xuat trong metanola duge pha voi 0,8 mL hdn hgp chat phan ung Folin-Ciocalteau fenola v i 2,0 mL caebonat natri (7,5%). Hdn hgp duoc khuay diu nhd thiet hi Vortex v i pha loang trong 7 mL nude eat vi d l trong bdng tli ti-ong thdi gian 2 gid d nhidt do phong d l phan ting xay ra. Hdn hgp sau phan ung dugc ly tam trong 5 phut d toe dd 15O0 vdng/phut. Dich long phia trdn (supernatant) dugc thu h l i v i do dd hdp thu d bude sdng 765 nm b<ing thiet bi do quang pho Shimadzu (Nhit Ban). Mlu tring doi chiing la metanola. Axit galie (Merck, Diic) duge str dung nhu chdt chuan v i k i t qua dugc tinh toin theo duong lugng axit gaUe (mg/lOOg). TTii nghidm duge lap lai 3 ldn v i k i t qua the hien li k^t qua trung binh.
3.KFrQUAVA1HAQLUAIV 3.1. Khio s i t thdi gian ngim
Su thay doi dd dm cua gilng liia IR 50404 trong q u i trinh ngam bang nude cdt, d nhidt dd phdng (30
± 2°C) duge t h i bien b hinh 1. 6 giai doan ddu ciia qui trinh ngam gao lut d 0 gid d i n 3 gid ddu dd dm tang rat nhanh tii 13% ting d i n 25%, do liic niy chlnh lech giira d l dm trong hat va bdn ngoai hat cao nfin do dm dugc chuyin nhanh vao trong hat, 2-5 gidti^p theo thi dd dm cua gao bit dau tang chim vi gdn dai diem bao hda l i 29,1 ± 0,24%, do luc niy cic phin tit tinh bdt hiit nude truang nd lam khoang cich giiia eac phan tii nho lai ndn hut nude cham lai.
Kit qua nay phu hgp vdi nghidn ciiu ctia Bello vi ding tic gia (2004) cho thdy trong giai doan d^u ngam gao liic 0 - 2 gid bdp thu nude ting nhanh ehdng ldn do su hap thu vio phdi cua h a t Sau d6 M gid, hat gao hap thu nude tir tir va din mdt trang thii can bing hoac bao hoa. D6 dm sau 5 gi6 fliay dili khdng dang k l v i ty Id hdp tiiu l i rdt chim. Tmng mgt nghidn ciiu khac, Banchuen v i d i n g tic gii 54 NONG NGHIEP VA PHAT TRIEN N 6 N G THON - KY 2 - THANG 9/20W
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t (2010) d i g ^ nhin ring, khi ngdm 3 gilng Itia cua I Thii Lan (Niaw Dam Feuak Dam, Sangyod Phatthalimg v i Chiang Phatthalung) trong nude eat I thi sau 5 din 7 gid sd dat dugc trang thai bao hda.
! Dli vdi tilde, str gia tang d l dm cflng theo mdt tiln trinh tuong tu. Tuy nhidn, do am cua thde ting chim hon, sau 6 gio ngam thi do am mdi dat din 31,16%. Tir 6 gid tilp theo tiii dd dm tang cham va dat din dilm bao hda l i 38,9 ± 0,54% sau 12 gid ngim.
Thde do cd ldp vd trdu bdn ngoii ndn ham lugng nude ngdm vao se cham hon, tuy nhidn nhd kha ning giii dm cua ldp vd trau ndn do am bio hda ciia thde cao hon so vdd gao lut
3.2.7110 niy mdm
Kit qui thi nghidm cho thdy ti le nay mam cua thde (96,5%) eao hon dang ke so vdi gao lirt (88,2%) khoang 8%). Dilu niy cd thi l i do dli vdi thde, tat ea cac phan cua hat diu cdn nguydn ven va khi do am vi nhidt dp dat din trang thii thieh hgp, bidn tugng niy mam sd diln ra. Ngoii ra, gao liit trong q u i trinh xay cd thi lim gay mdm thde, vi viy lim ti Id nay mdm bi giim di. Diy cung l i mdt thuan lgi ciia vide niy mdm thde so vdi niy mdm gao liit. Kit qua nay cQng phu hgp vdi nghidn ciiu ciia Moongngarm and Sateung (2010) eho thdy ti Id nay mdm cua tiidc cao hon cua gao lut khoing 10%.
G?Dlljft
ThJrlgianfh]
Hinh 1: Si; thay dil dO dm ciia thde v i g^o Itit theo thdi gian
3.3. Cic tinh ch^t vit 1^ cua gao mdm tii thde v i g^olut
3.3.1 Hiiu suit thu hSi
Tl 1$ gao nguydn sau khi xat ctia gao mam tu thde li 65%, so vdi ti 1| gao nguydn sau khi xay thde dl t^o ra g^o lut l i 78%. Dilu niy cd till ly giai la trong qui trinh niy mdm, clu tnic ciia hat gao sd ylu di do eic enzym thiiy phin cic phin tit ldn nhu tinh
bdt d l tao thanh c i c chat cd khli lugng phin tu nhd nhu cic dudng don (Yang etal,. 2001). Kit qua cho thdy li gao mam tu thde khi xay x i t sd eho ti Id gao giy cao hon.
3.3.2. Bd ti-ohd vi dd bin gel
Dd trd h i la tinh trang bieu thi nhidt dd cdn thilt d l tinh bdt ho hda v i khdng hoan nguydn trd lai (Biii Chi Buu v i Nguydn Thi Lang, 2000). Dua vao do trd h i cd the dinh gii kha ning gao biln thinh com v i khdng hoin nguydn. Do trd ho cang cao thi nhidt do h i hda se thdp, dan den vide gao se ndu chin dd ding ban d nhidt dd t h ^ . Do trd h i eua gao phin anh thdi gian ndu com nhanh hay cham, do trd h i cing cao thi thdi gian nau com cang ngin (Pamsakhora v i Noonhonm,2008).
Theo bang 1 ta nhan thdy, q u i trinh niy mdm sd lam tang miic dd tro h i cua gao. Gao mdm tu gao liit va gao mam tu thde nay mam deu cd do trd h i cdp 3, cao hon so vdi dd trd h i ciia gao liit la d cap 1. Do dd gao mam sd cd thdi gian ndu chin ngan han so vdi gao lut
Bing 1: MOt s l tinh chdt vit I;^ cua eic lo^i gao (GL: gao Itit; GML: gao mdm tii ggo Iiit^ GMT: ggo
mdmtutfadc) Chi ueu
Ti 1$ gao nguydn Ba tri ho D6 Mn gel
Baa vitinh
%
Cap mm
GL
1 48,25±1,15'
GML 78'
3 56,85±2,05'
GMT 65"
3 58,25±1,75' Ghi chii: dc chii di khic nhau trin cung mit hing cua Cling gidng Ilia biiu thi su khic hiit y nghia cd thing ki omdcy nghla 5%.
Do ben gel dugc xac dinh bing chilu dai thi gel sau khi hat dugc nghien min, hap trong moi trudng kilm. Chieu dai thi gel cing dii thi dd bin gel cang thap. Gia tri dp bin gel se cho ta biet dugc tinh chdt cua hat gao sau khi ndu, nlu do bin gel cing cao (hay ndi each khic, chilu dai t h i gel cing ngin) thi hat gao sau khi nau se eting va hat se rdi rac ban.
Khi do bin gel thap, hat se mim va cd dO kit dinh cao han sau khi ndu (Cagampang etal., 1973).
Kit qua d bang 1 cho thay ca gao mdm tir gao liit vi gao mam tir thde diu cd chieu dii thi gel cao hon, tlie la do bin gel thap hon so vdi g^o lirt. Chilu ddi thi gel eua gao lirt nay mdm 56,85, chilu dii thi gel cua gao mam tir thde l i 58,25, trong khi chilu dii t h i
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gel ciia gao liit l i 48,25. Dilu nay cho thay cam gao mim se mem hon so vdi gao liit va cd kha nang dugc ua chudng hon.
3.4. Thinh phdn hda hgc ciia gao mam Thinh phdn hda hpc eua gao liit (GL), gao mam tu gao liit (GML) va gao mam tii thoc (GMT) dugc thi hien d bang 2.
Bing 2: TTiinh phdn hda hgc cua c i c loai gao (GL: gao liit; GML: gao mdm tii gao liit; GMT: gao
mam tii thde) Thanh phin
(SO Am Protem Lipit Hydratcacbon Duong khli Pro
Vitamin Bl (mg/lOOg)
GL
13,14 ± 0,5"
7,01 ±0,15"
1,95 ±0,07"
79,45 ± 0,15"
0,20 ±0,05- 1,98 ±0,12"
0,25 ± 0,02- GML
13,25 ± 0,44' 8,25 ± 0,20' 1,87 + 0,15' 78,25 ± 0,35'
0,95 ± 0 , 0 8 ' 2,05 ±0,08- 0,12 ± 0 , 0 1 '
GMT
13,43 ± 0 , 6 5 ' 9,45 + 0,15=
1,91 ± 0,08' 77,95 ± 0,24'
1,34 ±0,05- 2,10 ± 0 , 0 5 ' 0,27 ± 0 , 0 5 '
Ghi chu: dc cha di khic nhau tiin cung mot bing cua cunggidnglua bieu thisukhic biety nghia cd thdng ke omucy nghia 5%.
Cac thanh phan ea ban ciia gao liit nhu protein, lipit, hydratcacbon tuong ling la 7,01%, 1,95% va 79,45%. Ham luong protein eua gao liit giong IR 50404 phi] hop vdi nghidn ciiu ciia Kenedy va Buriingame (2003), trong do tae gia cho thay ham luang protein cua gao liit eua cac giong liia O. sativa thay doi tir 4,5% din 15,9%. Cae thanh phan hda hpc khac cung tuong tu nhu nghien eiiu eua Heinemann va dong tic gia (2005) cho thay ham lugng protein, lipit va hydratcacbon cua gao lut thay doi tir 6,34%
din 7,42%; 2,37% den 3.02% va 69,85% din 85% mgt each tuong ting. Su biln doi v l thinh phan hda hoc nay phu thudc vao nhieu nhan to khac nhau, vi du nhu giong liia, lugng nude cung cap, loai phin bdn, thdi diem thu hoach,...
Sau qua trinh nay mam, cd su gia tang dang k l ham lugng protein tong so va dudng khii, trong khi khdng cd sir khic biet cd y nghia vl ham lugng lipit tong so, hydratcacbon va ham luong tro. Ham lugng protem tong so gao mam tir thoc cao han so vai gao mam tir gao liit (9,45% so vdi 8,25%), dong thdi ham luang protein ciia gao mam cao hon ban so vdi ham luang protein ciia gao liit (7,01%). Dilu nay cd the la do trong qua trinh nay mam, mdt so enzym dugc
kich hoat va mdt so chat nita phi protein, vi du nhu axit nucleic dugc tao ra, dilu niy lam cho ham lupng protein t i n g sd tang ldn. Cac quan sit tuong tir ciing da dugc Traore va dong t i c gia (2004) ghi nhin lai.
Tuy nhien, khong cd su khac bidt dang k l giiia ham lugng hpit tong so va ham lugng tro giiia gao mamvi gao lut, mac du Upit ed the hi thuy phan trong qua trinh nay mam de san sinh ra nang lugng cdn thiet cho cac q u i trinh hda sinh va ly sinh xay ra trong hat.
Ham lugng dudng khii trong gao mam bi th6c thi eao bon dang k l so vdi gao lut v i gao mdm ttr gao lut khoang 7 lan va 1,5 lan mgt cich tuong ling, trong khi ham luang dudng khii ctia gao mdm tir gao lut chi cao ban 4,75 lan so vdi gao liit. Su gia tang cua ham lugng dudng khu la do tinh hot hi thiiy phan dudi tic dung cua enzym a-amylaza, enzym ddng vai trd chinh trong q u i trinh thuy phin tinh bdt cua hat ngii coc nay mam (Shu etal., 2008). Mdt s l phan ling thiiy phan khac cung cd t h i ddng gdp cho qui trinh thiiy phan tinb bgt thinh dudng, vi du nhu tic dflng cua enzym invertaza xuc tic vide thuy phin sucroza thanh glucoza vi fmetoza. Theo Traore vi edng sv (2004), glucoza vi fmetoza la 2 loai dudng khu quan trpng nhat trong q u i trinh nay mam liia miln, hat k6 va bdp, trong do h i m luong dudng khu ciia liia miln gia tang din 30 ldn.
Ham lugng cua vitamin Bl (thiamin) trong gao liit Cling gdn tuong tu nhu trong nghidn ciiu cua Deepa v i dong t i c gia (2008) tim thay him luong vitamin Bl ciia giong liia IR 64 khoang 0,4 mg/lOOg.
Ham lugng vitamin Bl trong gao lut nay mdm giam mgt each ding k l so vdi gao liit (0,12 mg/lOOg so v6i 0,25 mg/lOOg). Dilu nay cd t h i li do anh hudng cua vide ngam gao liit trudc khi nay mam, lam tin thdt eac vitamin tan trong nude nhu vitamin Bl. Ngugc lai, ham lugng vitamin Bl trong gao mdm tii thde thi khdng giam ma tham chi cdn tang mac dii khdng dang k l . Dieu nay l i do vitamin Bl duge Idp v6 tidu bao ve va khong bi tan vio nuoc trong qua trinh ngam.
3.5. Cic boat chdt stiih hgc
Ham lugng hop chat fenola tong s l dugc xie dinh tiieo phuang phip sii dung hdn hgp chdt phin ling folin-Cioealteau vi k i t qua duge t h i hidn theo duang lugng axit gaUc (Bang 3). Kit qua cho Uidy c6 sir khac nhau cd y nghla v l ham lugng hop chdt fenola tong s l giiia cic loai gao. Him lugng hgp chi 56 NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 2 - THANG 9/20M
KHOA HOC CdNG N G H £
fenola ting s l cao nhdt trong gao mdm tii thde, tilp din l i trong g^o mdm tii gao lut v i t h ^ nh^t l i trong gao liit (99,7, 85,ji v i 74,5 mg/lOOg m i t each tuang ling). Theo cdng b l dia Igbal v i d i n g t i c gia (2005), him Iugng hgp chat fenola tong s l fliay d l i 251-359 mg/lOOg cam gao. Tuy nhidn, trong trudng hgp nay, him Itrgng fenola ting s l dugc xae dinh trong gao chii khdng phai cam. Thdm vao dd, su tiiay d l i v l him lirgng hgp chdt fenola tong s l phu thudc vao loai hoat chdt fenola, dilu nay tiiy thuoc vao giong Ilia v i trang thii phit tiiln cua liia. Tlan va dong t i c gia (2004) d i tim thdy rang 60-feruloylsucroza va &- 0-sinapoylsucroza l i cic hgp chdt fenola chu y l u trong gao lut, hiy nhidn trong qua trinh nay mdm 2 chdt niy bi syt giam nghidm trgng, trong khi ham luong cua axit feruhe v i axit sinapinic, ciing l i cac hgp chdt fenola, lai tang cao trong q u i trinh nay mdm.
Bing 3: Him lugng c i c chdt c6 boat tinh smh hgc trong cic l o ^ g^o k h i c nhau (GL: g?io liit; GML ggo mdm tii g?io liit; GMT: gao
mdm ttr thde) Ho^tch^t
H?p chit fenola t^ng s6 (mg/lOOg)
GABA Cmg/lOOg)
GL 74,5 ±4,41
6,98*0,45 GML 8 5 , 4 * 5 , 4 5
44,50 ±0,67 GMT 99,7 ± 6,43
74,5 ±0,90
tong hgp thong qua qua trinh decacboxyl hda cua axit glutamic
Cdng doan ngim v i u trong qua trinh san xudt gao mam cd I h l l i m tang nguy co nam moc phit triln trong sin pham va ed kha nang tao ra afSatoxin.
Do dd, gao mam tiianh pham dtrgc phan tich ham lugng afOatiixin, k i t qua dugc t h i hidn trong bang 4.
Kit qua nay dugc d l i chilv vdi QCVN:
8:l:2011/BYr- Quy chudn ky tiiuit quIc gia doi vdi gidi ban dge to vi nam trong thue pham ap dung cho san pham gao phai so c b l trude khi sir dung lim thuc pham hoae lam thanh phdn nguydn Udu ciia thue phdm. Kit qua phin tich cho thdy san phdm gao mdm hi thde ciing nhu tii gao liit khdng bi nhidm aflatoxin. Nhu viy vide kilm soit t i t q u i trinh ngim va u da ban c b l nam m l e phit triln, tii dd ban e h l Idia nang hinh thinh aflatoxin.
Nghidn ciiu ciing tiln hanh phan tieh mit s l cic vi sinh vit giy bdnh nhidm trdn san pham gao mdm de dinh gii mtic dd d nhidm trong qui trinh c b l biln. Cic k i t qua thu duge eung duge t h i hidn b bang 4.
Bing 4: Kit q u i phin tieh mit s l vi sinh v$t v i h i m Iugng aflatoxin trong g ^ mdm GML gao mdm ttt gjto liit; GMT: ggo mdm t^ thde
Ghi chii: dc chd cii khic nhau trin cung mdt hing cua cUng gidng Iiia bidu thi sukhic biity nghia cd thdng ki & mdc y nghia 5%.
GABA li m | t boat ehdt sinh hgc cd g i i tri cao dli vdi siic khde, d i cd rdt nhilu nghidn ciiu lam sing vl khi ning h i ti-g siic khde eua GABA Oto va Ishikawa, 2004; Chung etal., 2009). Kit q u i phin tich cho thdy, him Iugng GABA trong gao mam tir g(io Itit cao hon 6,4 Idn so vdi gao liit v i gao mam tii thde c6 him liigg GABA cao hon 10,6 ldn so vdi gao liit Trong m | t nghidn ctiu tirong tu dli vdi gao mam hi g^o liit Ld Nguygn Doan Duy v i Nguydn Cdng H i (2014) cQng da cho thdy h i m lugng GABA hi gao liit niy mdm gilng IR 50404 cao hon 12,7 Idn so vdi gao Iiit Tuy nhidn, trong nghidn ciiu k l trdn, cic tic gia da tfivic hi|n dilu ki|n ngdm d pH 3 v i ii nay mdm tiong dilu ki|n yIm khi, vi viy Iugng GABA sinh ra sd cao hon. Him lugng GABA sinh ra lidn quan true tilp din him lirgng axit glutamic, bdi vi GABA dugc
Chi tidu
r i n g so vl vi sinh /at h i l u khi E. coli Salmonella
\flatoxinBl
Aflatoxin tong s l D o n v i
tinh cfu/g
cfu/g cfu/g
p g / k g
p g A g Gidih^n
5x10*
10^
Khdng p h i t hidn 5
10
K i t q u i
5ML
!xlO*
»
OiOng ) h i t li^n a 6 n g 3hit lidn
GMT 3xltf
30 KhOng p h i t hi^n
Kh6ng p h i t hi^n
Khdng p h i t h i ^ n
K i t q u a k i l m n g h i d m c h o t h a y Salmonella h o i n t o i n k h d n g x u a t b i d n t r o n g s a n p h d m . N g o i i r a m i t d o c i c vi s m h v i t k h i c l i t h d p h o n gidi h ? n q u y djnh, vi v a y s a n p h a m d i m b a o a n t o i n c h o n g u d i tidu d i m g .
4. KET LUAN
N g h i d n c u u c h o t h d y k h a n i n g s i n x u d t g ^ o m d m t r u e tilp t u t h d e v i s i n p h d m n i y e d ti 1$ n i y
N 6 N G NGHI?P V A PHATTRIEN N O N G T H O N - KY 2 - THANG 9/2014 57
KHOA HOC CdNG N G H £
mdm, ham lugng protein, dudng khii, vitamin B l Cling nhu cac chat cd boat tinh sinh hgc, dae bidt la ham lugng cac hgp chat fenola t i n g so va GABA cao ban so vdi gao mam sin xudt tir gao liit Tuy nhidn, gao mam tii tiidc cd ti Id gao nguyen sau khi xay xat thdp ban so vdi gao mam tii gao lut vi vay cd the su diing gao mam niy d l san xuat eac loai bgt dinh duong ed chiia h i m lugng chat hoat tinh sinh hgc cao, hoac cic san pham nude uong nhu sura gao mam. Vide san xuat gao mam tir thde se mang lai gia tri kinh t l cao ban so vdi tu gao liit, bdi vi gia thde thdp hon va ti Id nay mam cao hon. Tbdm vao do, viec san xudt gao mam true tiep tir liia ciing phii hgp hon khi phat trien d quy md cdng nghidp.
TAI UEU THAM K H A O
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219-230.
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A., Penteado M. V. C. and Lanfer-Marquez U. M., 2005. Comparative study of nutrient composition of commercial brown, parboiled and milled rice from Brazil. Joumal of Food composition and Analysis 18;
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THE DIFFERENCE OF PHYSICAL PROPERTIES, CHEMICAL COMPOSmONS AND BIOACTIVE COMPOUNDS IN GERMINATED ROUGH RICE AND GERMINATED BROWN
RICE OF CULTIVAR IR50404
Le Nguyen Doan D i ^ Summaiy
This study aims to evaluate the possibili^ to produce gennmated rough rice and compare the difference in physical properties, chemical compositions and bioactive compounds of these 2 kinds of germinated rice.
The result showed that the concentration of protein, reduce sugar and vitamin Bl in germinated rough rice were significantiy higher than those of germinated brown nee. Especially, the total phenolic compounds and GABA in germinated rough rice were much higher than those of germinated brown rice, proving that the germinated rough rice possesses higher bioactive compounds that bring the benefits to consumer's health. In addition, there were no significant difference in the gelatinization degree, gel consistency, the concentration of lipid and carbohydrate between gemiinated rough nee and germinated brown rice.
However, the unbroken rice ratio after milling of germinated rough rice was higher than that of germianated brown rice. Tbe products could assure the microbial quali^ and were not contaminated with aflatoxin, so it was safe for human consumption.
Ifey words: Germinated rough rice, germinated brown rice, GABA (f -aminobutyric acid), IR 50404.
Ngudi phin bi|n: TS. TVdn Thi Mai Ngiy nhin bii: 30/5/2014 Ngiy tiidng qua phSn bi^n: 30/6/2014 Ngiy duy^t dang: 07/7/2014
N 6 N G NGHliP VA PHAT TRI^N N 6 N G THON - KY 2 - THANG 9/2014 59
