KHOA HOC C 6 N 0 NGHE
AIXIH HUOIMG CLIA IXIHIET D O V A IMOIXIG D O CHAT K H O DEIXI Q U A TRilXIH THLIY PHAIXl D O T KHOAI LAIXIG
KHdiVG H O H O A
Nguy§n Ti^n Cu6ng', NguySn Thu H i ' T6MTAT
Qua Innh san xual siro glucose bi^n banh tu tmb boi doi hoi chi phi nSng lugng lon. Do do, qua trinh thiiy pban b nhi^t do thap hon nhi^t do bo boa ciia tinb bot trong dieu kien nong dp chat kho rat cao (2300 g/L) la hucmg tli moi c6 tinh kha quan. Tuy nhien, tren the gioi va b Viet Nam quy trinh nay chua dupc nghidn ciiu nhi^u cbo nguyfin lieu cii {sSn, khoai lang), mSc dii no da dime ap dung a quy mo cong nghi?p k^ tu tbap ni^n truoc cho cac loai hat. Khoai lang, voi nguon cung doi dao va il anh huong den an ninh luong thuc, tro thanh ngu6n nguyen lieu tiem ning cho qua trinh san xuat duong tir tinh bpt neu tren, Mgc Ueu ciia nghi6n ciru n^y la danh gia anh buong cua nhi?t dp va nong do co chat den qua trinh thuy phan bOt khoai lang va danh gia bieu qua ciia cac enzyme phu trp 6 nong do chat kho rai cao va nhiet dp duoi nhi^t dp ho hoa d^n hieu suat thuy phan. Bot khoai lang duoc chuan bi trong dung dich d^m acetate (pH 4,2) va thuy phSu bang enzyme Stargen 002 (1,5 mL/kg chat kho) 6 cac nong dp cp chat khac nhau (10-30% w/w) va nhi^t do khac nhau (30-55"C). Ket qua cho thay, nhi^t dp t6i uu cho qua trinh thiiy phSn \A 50"C. Vi$c b6 sung cAc enzyme phu trp (Accellerase 1500, Viscozym va Pectinex Ultra SP-L) lam tang hi^u suait thuy pbSn (10-15%, dat 85% 6 nong do 30% chat kho) va cho phep tang chal kho len toi 40%. Dpng bpc qua tnnh thiiy phan dupc mo hinh h6a iheo phinmg trinh thuc nghiem dang Micheahs-Menten cho phfip dy doan hifiu suat tbuy phan cue dai tbu dupc.
Tir khoA: IHioai lang, nong dg cbat kho cao. Stargen 002, thuy pban onbiet dg tbap. tinb bot nguyen.
I.DATVANDE
Su phat trien ciia qua trinh tmh ch^ sinh hpc (biorefinery) la mot trong nhimg huong phat trien kinh te quan trpng dua tren cac ngu6n tai nguydn tai tao. Glucose va cac duong l^n men noi chung la nguydn lieu chinh cho nganh cong nghiep smh hpc - thuc pham, Tuy nhi^n. cong nghe truyen thong san xuat duong tir tinh bpt tifiu hao nhieu nSng luong tir cac ngu6n boa thach (xang d^u, than) cho qua trinh dich hoa (95-105°C) va duong hoa (60-65°C) [1].
Chinh vi vay lam tfing gia thanh san xuSt cac san pham tir tinh bpt. De cai thien van d^ nay, qua tnnh thiiy phan co the dupc tien hanh b nhiet do thap hon.
Cu th^, tinh bpt dupc thuy phan (dich hoa va duong boa dong thoi) a nhiel dp duoi nhiet do h6 hoa, nhu.
54 C cho Ilia mi, 60 C cho khoai tay hoac 65'C cho ngo [2]. Cong nghe nay duoc tion hanh nho mot s6 enzymee amylase co kha nang thuy phan bnh hot song va khong cdn cac buoc ho boa va dich boa nhu qua trinh thong thuong, cho phep giam 10-20% mtic tieu thu nang lupng [3]. Them vao do, cong nghe dupc hen hanh b ndng do chat kho rat cao (VHG,
' \ K-n Cong ns;hc Sinh hpc va Cong nghe Thuc pham.
Truong Dai hpc Bach khoa Ha Noi Email: cuoiii; nguvcnlicii I ("iiuM edu.vn
>300 g/L) nhim muc dich dem lai nong dp san pham cao dupc xem nhu c6ng nghfi moi trong thap men gan day. Quy trinh nay da dugc iing dung trong san xuat ethanol sinh hpc vi no giiip giam dang ke cbi phi nang lucmg, xu ly nudc thai ciing nhu ddu tu ca sa ha tang thi^t bi 14]- Cong nghfi VHG da dupc ap dung b quy mo Ion ke tir thap mfin truoc cho cac loai hat ngu coe (ngo, liia my, dai mach) nhung hi^m khi cho cac loai cCi [5, 6]. Cac loai nguyfin lifiu cii (sSn, khoai lang) co nguon cung ddi dao, ham lupng tinh bdt cao, gia thanh thap va it anh huong den an nmh luong thuc. Tai Viet Nam, cac loai cu, vi du nhu khoai lang, la nguyen beu diu vao vkt phu hpp do cay dfi trong doi vdi cac loai dat va di^u kien khi h^u khac nhau: chi phi san xuat thap, gia thanh re; ngudn cung ddi dao trong ca nam (dang tuoi hoSc khd);
ham Itrpng tmh bdt cao va tan dung duoc phu pham cho cac nganh cong nghidp khac. Nhiet dp bat diu hd hda cua tinh hot khoai lang phu thupc vao gidng khoai va phd bien trong khoang 60-69'C [7].
Muc beu ciia nghien cuu nay la (i) nghien cuu anh huong aia ham luong chat khd va nhifit dp ciia qua tnnh thuy phan enzyme bdt khoai lang or nong dp chat khd cao va dudi nhifit do hd hoa de thu duoc ham lucmg duang glucose cao va (ii) nang cao hieu
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 11/2019
KHOA HOC CdNG N O H t suat thuy va tang ham luaiig chat kho ban dau bang
each sii dung cac enzyme phu tra.
2. VAT UEU VA PHUONG PHAP N G H e i CUU 2.1. Vat li$u nghifin a m
Khoai lang thai lat, say kho {Ipomea batatas spp), gidng Hoang Long, dp am <12%) duoc mua tir huyen San Ducmg, tinh Tuyen Quang. Khoai lang khd dupc nghien bang may nghifin btia va bao quan trong cac thiing kin, khd, tranh mdi mpL Bpt khoai lang cd dp am <12%, nhiet dd hd hoa 62-65°C [81 va kich thudc hat < 125 pm dupc sii dung trong nghien cuu nay.
Enzyme Stargen 002 (chua hdn hpp alpha va glucoamylase, 560 GAU/g; pH= 4.(M,5; nhifit dp thich hop 20-65°C), Viscozyme L (betaglucanase, 100 FBG/g; pH= 3,3-5,5; nhifit dd thich hpp 25-55X), Accellerase 1500 (cellulase, 60 FPU/mL; pH= 4,0-5,0;
nhifit dp thich hpp 50-65°C), PecUnex Ultra SP-L (pecbnase, 9500 PGU/mL; pH= 4.0-5,0; nhifit dp thich hpp 40-60°C) sir dung trong nghifin ciiu duoc cung cap bdi Cong ty Dupont va Novozymes.
2.2. Phirong ph4p nghien cuu 2.2.1. Phuang phap phan tich hoaly
Lirong gtucos« n n k r
Cac tinh chat va thanh phan ctia bpt khoai lang duoc phan tich theo Tifiu chuan Vi^t N.mi 0^' ' bao gdm cic chi tifiu: do am (TCVN 9706:2013). hai»
lupng protem tdng CrC\'N 4328-1:2007), hani Iiwn&
chat xa (TCVN 9590:2013), dp tro (f^^™
8124:2009), ham lupng pecbn thong qua canxi pe*^'^*
[9].
Z22 Phuong phap xac dinh ham luung ^"^ '^^^
tdng, duong khu va hifu suat thuy phan Ham lupng tinh bpt tdng dupc xac dmh thdng qua ham lupng dudng khii. Tinh bpt tdng duoc tinh toan til ham lupng dudng khir (quy ra glucose) sau khi thiiy phan bang axit (HCI 2%) trong 2 gid. Ham luong dudng khii dupc xac djnh bang phuong phap DNS dua frfin phan ung tao man giiia dudng khu vdi thudc thu la axit dinitrosalicyUc [10). 0.5 mLmau sau khi ly tam duoc b-pn vdi 1,5 mL DNS sau do dun sdi b-ong 5 phiit. Hdn hgp dupc lam ngudi dfin nhiet dd phdng va dp hap thu ciia mau dupc do d buoc song 540 nm. Dudng glucose dupc su dung de xay dimg dudng chuan, Lupng duong khii thu dupc dupc bieu thl bang glucose. Hi^u suat thuy phan duoc tinh theo cdng thuc:
Hieu STiat thuy phan (%) = tci'i
Lvong glucon Iy thuj-er Trong do [Giu]: ndng dp glucose trong dich (g/L); FTB: ham lupng cua tinh bdt trong ca chat (g/g chat khd); [CKoJ: ndng dp chat kho ban dau (g/L). Hfi sd 1.111 la hfi sd chuyen ddi tir tinh hot thanh glucose.
2.2.3. Bd til'till nghifm
Be danh gia anh hudng ciia nhiet dp dfin qua trinh thuy phan, hot khoai lang dupc chuan hi trong dem axetat (pH=4,2) vdi nong dp chait khd 20% w/w.
bd sung enzyme Stargen 002 (1.5 mL/kg chat khd) rdi tien hanh thuy phan d cac nhiet do khac nhau la 30. 40. 50 va 55T. Vdi anh hudng cua ndng dd chat khd, chuin bi hdn hpp bdt va dem axetat (pH=4.2) d cac ndng dd chit khd la 10, 20, 30%, bo sung enzyme Stargen 002 (0,8 U/g chit khd) rdi tien hanh thuy phin d SOX, 60 rpm trong 72 gid. De cai thien hieu qua qua trinh, h6n hpp bdt d- 30% chit kho sau khi bd sung enzyme Stargen 002 dupc bd sung cic enzyme phu tra: Accellerase 1500: 0.03 FPU/g chat khd:
Viscozyme: 0.04 FBG/g chat khd; Pectinex Ulfra SP- L: 4,3 PGU/g chat khd va tien hinh thuy phin a 50°C. 60 rpm b-ong 72 gid. Tifin hanh bd sung thu nghifim enzyme phu tra vdi ndng dp ca chit cao han
- (Eq. 1) 1 i n FTP [CK^]
(40, 45% w/w chat kho) de khao sat qua binh vi dinh gia hi^u qua ciia cic enzyme da bd sung. Cic miu dupc liiy tai thdi di^m 0, 3, 6, 9,12,24,48, 72,96, 120, 146 gid, enzyme duac vb boat bing KOH 2,5N (pH 2 11) tir dd xac dinh lupng dudng khu va hifiu suit thuy phan,
2.2.4. Md hinh ddng hgc
Dpng hpc qui trinh thuy phan tinh bdt cd the duoc md hinh hda bang cac phuong binh ly thuyet, ban thuc nghifim va thuc nghifim. Trong nghien cuu niy, md hinh thuc nghifim cd dang tuong br nhu md hinh ly thuyet Michealis-Menten duoc sir dung d l mo hinh hda hifiu suit thiiy phan theo thdi gian thuy phan. Md hinh niy cung duoc su dung trong mot sd nghien ctiu birdc day [11,12]:
^ = G)-©r--
Trong io Ava Bh cac hing so. khi bieu lien (t/lD,- AD theo tcho ta he so goc la il/A) v;. giao diem vol true tung tai (BIA). D„ la hieu suit i i thoi diem ban dau. Hang so 51a thoi gian d^ dat ducjc dai N O N G NGHIEP VA PHAT TRIEN N O N G T H 6 N - KY 1 - THANG 1 ! /2019
KHOA HOC C 6 N G N G H £ lui?ng AJ2 vdi A li hifiu suat cue dai co thfi thu dirpc.
Trong nghifin eiiu nay, dai luong dupc md hinh hda, D, la ham luang glucose tao thinh.
2.2.5. Xulysolieu
Cic phep do dupc lap lai it nhat 3 lan b> dd xic dinh gli tri trung binh vi dp lech ehuan. Su sai khic cd nghia cua eie gii tn trung binh dupc danh gia bang phuang phap phin tich phuang sai (ANOVA) va test Duncan bang phan m^m SPSS vdi muc tin ciy p <0,05.
8.KETQUAVAT1IA0LUAN
3.1. Tliinh phdn ciia bdt khoai lang
Thinh phin eiia nguyen hfiu bdt khoai lang duoc trinh biy trong bang 1. Bdt khoai lang dmn: su dung cd dd am < 12%, diy li dp am thich hop cho qua tnnh bao quan va van chuyen. Thinh phin tinh bot eua khoai lang tuong doi cao, chidm khoang xip xi 70%, him lupng protein khoang 6%, ham luong xa va tro thap (dudi 2%). Vdi ham lupng tinh hot cao, ngudn cung cap ddi dao (san lupng nim 2016 dat khoang 1.269 trieu tan), it inh hudng den an nmh luang thuc, gii thanh re, cung vdi nhu ciu ning cao gii tri sin pham ndng nghiep thi khoai lang la nguyfin lifiu phii hpp cho muc dich nghifin ciru ciia de tii. Kich thudc hat bdt sau nghidn duoc khdng ehe nhd hon 125 pm nhim tranh inh hirdng cua tuang tac hat - hat den qui trinh hap phu enzyme lfin bfi mat hat bot.
Bing 1. Thinh phin nguyfin ligu bdt khoai lang Chl tieu
Do am Duong khir Tinh bot Protein Xa Pectm Tro
g/100 g bot 11.22+0.10 4.39 ±0.11 60.70 ± 2.60 .1.40 ±0.57
1.87 ±0.1.1 3.0.^ ± 0.02 1.62 ±0.10
% chait kho 4,94 ±0.12 68.37 ± 2.93 6.08 ± 0.64 2.11 ±0.17 2.69 + 0.02 1,82 ±0.11 3.2. Anh hirdng cua nhi^t dO d^n qui trinh thuy p h ^
Anh hirong cua 4 niixc nhifit dd khac nhau 30, 40, 50, 55°C den luong duong khu tao thanh vi hifiu suit thiiy phin dupe gidi thieu hinh 1 va bang 2 (nhifit dp thiiy phin cao nhat la 55°C nim dudi nhiet dp bit dau hd hda ciia tinh bdt khoai lang tii 62 C). Kfit qua thu duoc chi ra ring ham lupng dudng khu tao thanh ting khi nhifit dp cua qua trinh thuy phan tang (Hinh 1). Cu the, a 12 gid- diu ctia qui trinh, luong dudng khii t^o thanh khdng cd sir khac biet nhifiu giira cic dieu kien thiiy phin, tuy nhifin, anh hudng ciia nhiet dp duoc quan sat ro rang trong giai doan sau aia qua
trinh. Luong dudng khii sinh ra d difiu kien 50 vn 55X dat gap ddi lupng dudng khir sinh ra df 30"C (him luong duang khu tao ra tinh theo glucose lin luat li 130,6 a SOX, 135.5 d 55°C vi 65,4 g/L a 30'C).
Thfim vio dd, viec tang nhifit dd khdng chi lam ting hifiu suat ma cdn lim nit ngin thai gian thuy phan.
Hifiu suat cue dai ciia qua trinh thuy phan khi tifin hanh d 30. 40, 50-55"C dat duac brang ung sau 146, 96 va 72 gid xii ly (Bang 2). K^t qua nay li kha quan khi so sanh vai cic nghifin ciiu trudc day. Li va cs.
(2012) nghien cuu qua trinh thiiy phan tinh bdt ngd va tieu hie mach d 30% chat khd vdi enzyme Stargen 002, sau 96 gid hieu suat thiiy phin d^t 64% ddi vdi tieu hac mach va 60% ddi vdi ngd [13|. Hay vdi qua trinh thiiy phan tinh bpt khoai tiy d 5% ehit kho, d 37"C vdi dieh ehiet bi Myeobaetenum aurum B8.A thi sau 148 gidf eho hieu suit thiiy phin dat khoing 50% [14]. Cac sd hfiu trfin cung phu hpp vdi nghifin cim ve anh hudng eua nhifit dp den hing so hap phu va lupng enzyme hap phu tdi da len be mit hat tinh bot ti-ong qua trinh thiiy phan, ket qua ting nhiet dp tir 30 lfin 50 C lam tang gia tn ai lue giira enzyme vi CO chit ddng thai dp hap phu cue dai ting han 4 lin [15].
Tliuy phin tinh bdt dudi nhifit dd hd hda la qua trinh thuy phan mi cac hgt tinh bdt cdn d trang thii ban tinh th^. khdng tan trong nudc nfin cac enzyme phai boat dong tren pha rin lam can trd sir hap phu ciia enzyme lfin bfi mit co chat tir dd ban ch^ qui trinh xiie tic thiiy giiia enzyme va ca chat din d^n lim giim hifiu suit thuy phan. Cf nhiet dp 50 va 55 C la nhiet dd gin vdi nhiet dp hd hda cua tinh hot khoai lang nhat, hat bnh bot cd th^ hap phu mpt lirpng nudc vi truang nd mdt phin, cau tnic be mit hat trd nfin Idng leo, viing vo dinh hinh md rong lim cho enzyme dfi tan cong vio ca chat han tir dd vira lim tang hieu suit vira lam nit ngin thdi gian thiiy phan..
Khi so sanh hifiu suit thuy phan d 50 va 55°C nhin thay df 55°C cd eho hieu suit thiiy phan cao hon 1 chlit so vdi d SOX (lan luat li 89,8 va 86,8%) nhung so vdi ehi phi de gia nhifit tir 50 lfin 55 C thi su khae bifit nay la khdng dang ke. Vi viy de vua tifit Idem chi phi ning lupng vira dam bao hifiu qua thuy phin thi SOX se la nhifit dd duoc chpn cho cac thi nghifim tifi'p theo.
Hinh 1 vi bang 3 cho thay mo hinh de xuat (phuong trinh 3) phii hop vdi dir lifiu thuc nghifim va
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2019 65
KHOA HOC CdNG NGHl md ta tdt ddng hoc qua tnnh tao thanh glucose theo
thdi gian vi he so hdi quy r xip xi 1. Tirong tir nhu phuang trinh Michaelis - Menten co ban, be sd .'I co Ihfi dupc COI la ndng dd glucose tdi da cd the thu dupc. d cae nhifit dd thiiy phin khae nhau, he sd A thay ddi trong khoang tu 114,9 den 148.7 g/L va khdng cd su khac bifit giiia hai nhiet dp thiiy phan SOX vi 55X Hfi so A trong cdng nghiep, ddng mot vai trd quan trong trong vific dir doin vfi hifiu suit thiiy phan cue dai va quyfit dinh thdfi diem hop ly de ngung qui trinh thuy phan mot each kinh te nhit.
3.3. Anh huong cua ndng dO co chit dfin hi^u su^t thuy phan
- - - • t " '
Hinh 1. B\6a ddi lupng dirdng khu t^o thinh (quy ra glucose) theo thdi gian thiiy phin d cic nhi^t dO thiiy
phin khic nhau (ndng dO chit khd ban diu 20%) (n6t dut phirong trinh md hinh thyc nghidm dpng
hpc qui trinh t^o thinh glucose) Bing 2. Anh hudmg cua nhi^t dd d^n hi^u suit thiiy
phin bpt khoai lang (2()% chat khd)
10
Hinh 2. Anh hudng ciia ndng dd ca chit d^n hi^u suit qui binh thuy phin bdt khoai lang (50°C)
Ket qua ve su anh huong eiia nbiet dp den hifiu suit ciia qua ti-inh thuy phan dupc the hifin ti'ong hinh 2. Tir dd thi cho thiy, d ca 3 ndng dp chat khd khic nhau, hifiu suit thiiy phin d^u tang dan Iheo thai gian trong dd a ndng dp chat khd loang cho hifiu suit thiiy phan cao nhat (khoang 93,34%) va giam dan khi ting nong dp chat kho. Hifiu qua thiiy phin khong ed su khac bifit giiira eae difiu kifin ti'ong khoing 10 gid dau ciia qua trinh. Tuy nhien, anh hudng cua ndng do ca chit dupc quan sat Ihay ro sau giai doan niy. Nong dp chit khd loang (10%) cho hifiu suit thu hdi cao hon bin d dieu kien ndng dp chat kho tmng binh vi cao. Vi^c ting nong do chat kho tir 10 len 30% lam giam hifiu sual khoang 20%
(bieu suit thuy phan d 10% vi 30% chat khd lan lupt li 93,3 va 70,6%). K^t qua nay cung phii hop vdi cac nghifin ciiu trude day vfi anh hudng ciia nong dp ca chat d^n hifiu suat thiiy phan, O ndng do chat khd lon, Nguyfin va cs. (2017) ket luin ring viec ting ndng dd eo chat lim giam ding k^ do hap phu ciia enzyme lfin ca chat (dp hap pbu giim tu 84,8% o 10%
CO chat xudng chi edn 65,6% d 30% co chat) va su tang ndng dp ca chat din dfin giam hifiu suit thiiy phan [15]. Su giam hifiu suit nay trudc het la do tuong tic giira hat vdi hat lam giim kha ning khuech tin ciia enzyme vao co chat eung nhu anh hudng den cac qua tiinh bniyen nhiet, chuyen khdi; sau do > '^c nong dd co chat cao sfi lim thua co chat, din df-n su bat cap sai cua enzyme voi co chat tao cic phiic khdng ed kha nang phin Iy tao sin pham tu flo lim giam il luc giiia enzyme va ea chat Hon niia. i r nong
NONG NGHIEP VA PHAT TRIEN NONG THON-KYI -THANG 1 i/2019 Nhiet do ("O
30 40 50 55
Thm gian thuy phan
(h) 146 96 72 72
Hieu suiit thuy phan (%) 57.8 ± 2.7'' 69..1 + 2,.3'' 86.9 ± 1.4' 89.6 ±1.9'' (Gia tii the hien la tnmg binh ± dd lech chuan:
cac gia tn cd k}' tu chu cai khac nhau thi khac bift cd y nghia thdng ke (p<0.05)).
Bang 3. Hing sd ddng hpc qua trinh t?io thinh glucose (ndng do chit kho ban diu 20%)
>1iuM (lo_(_0_-;l_i^/L) ; B (h) r (/) ,U) 111.9 ' iU.9 0.9632
126.li 14S.7 14S.7
:!3.3 20.7 20.S
0.9828 0.9925 1 0.9953
KHOA HOC CONG NGHE dd CO chit cao. dp nhdt ciia dung dich ting len,
khdng gian giua cae hat tinh bpt bi co lai, ^ le tiTiong na giam lim giam kha ning tifip xuc giiia enzyme vdi ca chit, tu do Iam giam hifiu suit qua tiinh. Tuy nhien, tai ndng dp 30% w/w chit khd, hieu suit thiiy phan dimg lai b khoang 70% la chip nhan dupc khi Unh toin den luang dudng tuy^t ddi thu duac va hieu qua thu hoi cua ca qui trinh. Hieu suit nay li tuang ddi kha quan khi so sinh vdi cac nghifin aiu trudc diy.
3.4. Cii thi^n hi§u quA qui trinh thiiy phin bing cich b6 sung cic enzyme phti trpf
Tir cic thi nghifim trfin, xac dinh dupe difiu kifin thiiy phin phii hop li: kich thudc hat < 125 pm, nhiet dd SOX, pH = 4,2 cho hifiu suit dat khoang 70%. De phli hpp vdi quy md cong nghifip vi ning cao gia tri kinh tfi can nghifin ciiu cic bien phip d l lim ting hieu suit qua trinh thiiy phin hoac cho phfip nang cao hon ntra ndng dp ca chat. De tang gia tri kmh tfi va vi^c ling dung rpng rai d' quy mo cong nghifip cho quy trinh dudng hda khong gia nhifit. mdt phuong an mang nhieu hiia hpn dupc dua ra la ting ndng dd ca chat (very high gravity - VHG). Cong nghe VHG dupc tien hanh d nong dp chat kho trfin 300 g/L. Tuy nhien trong qua trinh thuc hien thi nghiem nhin Bing 4. Anh hirdng ciia enzyme phu trpr d^n higu
thay dung dich bdt khoai lang d ndng do ehit kho cao ed do nhot r:at cao do thinh phan ciia bpt khoai lang ngoai thanh phin ehinh la tinh bdt cdn ed cic thanh phan khac nhu protein, cellulose, hemicellulose. P-giucan. pectm....[16]. Nhiing thinh phan nay vua lam ting dp nhdl eiia dung dich ban diu, vua lam can trdf su tiep e$n ciia enzyme thiiy phan vdi tinh bdt
Nghien cuu niy su dung cac enzyme phu trp bao gdm Accellerase 1500: 0,05% chat khd; Viscozyme:
0,05% ehit khd; Pectinex Ulti-a SP-L: 0,5% ehit khd de lim giam dd nhdt, giii phdng tinh bpt du tru ra khdi te bao thue vat tir dd lam ting hifiu suit thiiy phan. Kfit qui dupc the hien trong bing 4 cho thay, khi bo sung ehe pham Viscozyme hi^u suit thiiy phin tang khoang 5% (bi 70,8 Ifin 75,5%) so vai khi chi diing che phim Stargen 002. Ngoii ra khi bd sung thfim eae enzyme phu trpf khic niia nhu Accellerase hay Pectinex lim tang hifiu suit qui trinh bi 10% (vdi Viscozyme vi Pectinex) dfin 15%
(vdi Viscozyme vi Accellerase). Khi so sinh hifiu suat niy vdi quy trinh thuy phin truyfin thdng cd qua giai doan dich hda va dudng hda (hifiu suit khoang 92,6%) thi cd the ket lugn bifin phip bd sung enzyme phu trp' giup cai thien ding k l hifiu qua qua trinh.
suit thuy phin bpt khoai lang b 50°C vi pH - 4 ^
Ndng dd chal kho (%) Hifiu suit thuy phin (%)
Stargen
30 70.8 + 0,6^
Stargen Viscozyme
30 75.5+1.6"
Stargen Viscozyme Accellerase
30 85.1 + 1,5"
Stargen Viscozyme
Pectinex 30 81,9+ 1.7'
Stargen Viscozyme Accellerase Pectinex
40 74,9 ± 1 .S""
(Gia tri thi hifn la tnmg binh + df Ifch chuan; cac gia tri co ky tu chu cai khac nhau thi khac biet co y nghia thdng ke (p<0,05)).
Vific cai thien hifiu suit ciia qua trinh thuy phan ed the giai thich dua trfin cic tie dpng khic nhau cua cie enzyme phu trp: che pham Viscozyme (chua p- glueanase) thiiy phan eae bfin ket p - 1, 3 (4)- glucosidie cd trong thanh te bio. Accellerase (chiia cellulase) thiiy phin cellulose vi Pectmex thuy phan hop chat pectin - thinh phan trong bpt khoai lang (chicm gin 3% chit kho). Cic tic ddng niy lam giim dd nhdl tlie thdi ctia dung dich cung nhu lam giai phdng tinh bpt khdi mang ludi trong te bio de enzyme thuy phin tmh hot dfi tan cdng hon tir dd lim ting hieu suit thiiy phin. Sriroth vi cs. ciing thu duoc ket qua tuong tir khi iing dung hdn hpp cellulase vi pectinase bren ca chat hot sin [17]. Hifiu
qua glim do nhdt dich thuy phin nhd pectinase vi p- glucanase duoc ehung minh trfin nhifiu co chit dang eii khae nhu khoai tay, cii cai dudng...[5]. Bfin canh dd. viec su dung eac enzyme phu tra lam giim dp nhdt ciJa dung dich edn eho phep ning cao ndng dp chat khd sii dung. Nlu chi sir dung che pham Stargen 002 thi qua trinh chi tiln hinh duoc d nong dd 30% chat khd do dung dich rit nhdt, khong thl khuay trdn duoc thi vific sir dung hdn bop chl pham Viscozyme va Accellerase cho phep tien hinh qui trinh Of ndng dp 40% chit khd. Kit qua, hifiu suit thtiy phin dat 74,9% sau 72 gid (khdng cd su sai khac ed y nghia thdng ke vdi mau 30% chat kho). Hifiu suit nay
NONG NGHIEP VA PHAT TRllN NONG THON - KY 1 -THANG 11/2019
KHOA HOC CONO NGHE la kha quan khi ap dting nong dp chat kho i^t cao
nay cho qua tnnh thiiy phan, 4.KETUMN
Nghien ciiu da chiing minh su anh huong ciia nhiet do (30-55°C) va ndng do chat kho (10-3(W) din hieu suat qua trinh thtiy phan hot khoai lang khong ho hoa Dieu kien thuy phan phu hop la a 50"C. 30%
chat kho ban dau. pH=4.2 va hieu suat qua trinh dat 70%. Bo sung cac enzyme phu trg (Accellerase 1500:
Viscozyme; Pectinex Ultra SP-L) da cat thien hieu qua qua trinh bang each tang 10-15% hieu suSt thiiy phan hoac cho phep nang cao nong do chat kho len den 40%. De lam tang gia tn kinh te va ap dung co hieu qua hon a quy mo cong nghiep. can Co cac nghien ctiu sau hon v4 viec bo sung co chat theo me d^ han ch^ toi da cac anh hucmg cho qua trinh chuyen khdi va tnjy^n nhidt.
i n MM ON
Nghien cuu nay dupc tai tip- bdi Quy Phat tiien Khoa hoc va Cdng nghe Qudc gia (NAFOSTED) tiong de tai ma sd 10&NN.02-2016.56.
TAI UEU IHAM KHAO
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Bioresource Technology. 2000, 71(1)- p, 63-69 N O N G NGHIEP VA PHAT TRIEN N O N G THON - KY 1 - THANG 11 /2019
KHOA HOC CONG N G H |
LOW TEMPERATURE AMYLOLYSIS OF SWEET POTATO FLOUR AT VERY HIGH GRAVrTV:
IMPACT OF ENZYMATIC HYDROLYSIS CONDmON
Nguyen Tien Cuong, Nguyen Thu Ha Summaiy
The conventional process of glucose producUon from starch demands an important energy and leading to the high co-^l Thus, the low-temperature hydrolysis at \'er\- high gravity (>300g/L) of starchy substrates presents as an emerging technology. However, this process has been rarely applied for roots and tubers (cassava, sweet potato), although it used at large scale since the last decade The sweet potato presents as a raw matenals source for starch-based sugar production in Vietnam wntb tbeir abundant supply and less effect on crops security. The aim of tbis study was to investigale the impact of substrate concentraUon and temperature on the hydrolysis of sweet potato flour and to evaluate the effect of amylolysis enzymes at very high gravity and at sub-gelatmisaUon temperature in the hydrolysis yield. Sweet potato flours were prepared m acetate buffer (pH 4.2) and bydrolysed witb Stargen 002 enzyme (1.5mL/kg dry matter) at different subsUate concentrations (10-30% w/w) and temperature (30-55''C). The optimum temperature for hydrolysis was 50'C. The addition of auxiliary enzymes (Accellerase 1500; Viscozym and Pectinex Ultra SP-L) increased the hydrolysis yield (10-15%, reached 85% for 30% w/w) and allowed to raise the dry matter up to 40% w/w. KineUc hydrolysis was modelled by empirical equation and that can predict the maximum hydrolysis yield.
Keywords: Granular starch, higb gravity, low lemperalure hydrolysis. Stargen 002, sweet potato.
Ngir6i phin bi$n: TS. Nguyen M ^ n h DQng Ng^y nh$n bii: 17/5/2019
Ngiy th6ng qua phin bi^n: 18/6/2019 Ngiy duy$t ding: 25/6/2019
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 11/2019
