Trin Thi Hoan vd Dtg Tap chi KHOA HQC & CONG NGHE 92(04): 19-24
ANH HirOfNG CUA C A C C A C H THlTC C H E B I £ N D ^ N T H C J I GIAN P H O I , SAY VA T H A N H P H A N H O A H Q C CUA B O T LA S A N
Tran Thj Hoan*, TCr Trung KiSn Truang Dgi hgc Nong Idm - DH Thdi Nguyen TOM T A T
Chung toi di th( nghi?m 8 cich thuc chi bien Ii sin khic nhau, k^t qui cho thiy:
Siy khd li sin bing di?n ning (16 siy, tu siy difn) cd nhi^u uu di^m nhu: Thdi gian lim kho nhanh, it tdn hao cic chit dinh dudng vi caroten, giim dugc phin ldn dOc t6 HCN. Tuy nhiSn, trong diSu ki|n hifn nay ciia nudc ta, chua thi ip dyng rdng rii phucmg phip niy.
Bim nhd li, phai kho di riit ngin ding ki thdi gian phoi, bio ton cic chit dinh duJmg vi caroten tdt hon, ddng thdi logi bd dugc nhilu dgc t6 han so vdi phuong phip khic. Vi viy, nfin ip dyng phuang phip niy trong sin xuit bdt li sin.
Cac chit dinh dudng vi caroten giim nhanh trong qui trlnh bio quan; sau 6 thing bio quin, protein giim di 20 % protein, 27 % lipit, 88 % fi caroten. VI viy, sau khi ch€ biin, cin dua hgt li sin vio sii dyng ngay, khdng bio quan qui lau.
Tir khda: Bgi Id sdn. cdch thuc che biin, thai gian phai, ihdnh phdn hoa hgc
MCJDAU
Hay sin sau khi cit cd khi nang tai sinh cao, lang suat chat xanh ldn. La san giau dinh iudng, die biet la protein (Nguyin Khac
<hdi, 1982 [I]), ngoai ra nd con chda mgt ugng ding kd xanthophill cd tac dyng lim ang do dam miu ldng do trung ga. La san dd Jid (phai ning hogc siy), de bao quan. Tuy ihien, trong Ii san cd chua dgc td HCN gay nh hudng den gia sue, gia cim. Dd tim ra ich thuc chd bien thich hgp (de lam, mat it hit dinh dudng, loai bd nhieu dgc td), chiing 5i tien hanh nghien ciin: "Anh hie&ng cua dc cdch thuc chi bien den th&i gian phoi, dy vd thdnh phdn hda hgc cua bot Id sdn) "
rai DUNG VA PHU'ONG P H A P IGHJENCUtl
Npi dung nghiin ciru
Ighien cuu anh hudng cua cac each thuc che ien ddn thinh phan hda hgc cua bdt la sin 3LS), tren co sd dd tlm ra cich thdc chl bien lich hgp gay tdn that it cac chat dinh dudng a giam dugc nhieu dgc to HCN.
Ddi tuffng, dia ^m vd thai gian nghiin ciru Ddi tugng nghien cdu: Gidng sin KM94
Dia dilm nghien cdu: Trung tam Thyc inh Thyc nghi$m, trudng Dai hoc Ndng am Thai Nguyen.
Tel 0988520086
- Thdi gian nghien ciiru: Nam 2009 - 2010
* Phuang phdp nghiin ctru
La sin dugc hai, bd toan bg cuong, mdi cdng thdc thi nghiem liy 10 kg li dd che bien. Ddi vdi cich thuc cd su dung ngam nudc thi tien hinh ngam nudc trong 4 gid, sau dd de rao nuac vi phai ciing thdi gian vdi cic cdng thuc cdn lgi. Sau khi nghien thinh bgt, lay bgt Ii sin ciia each thuc che bien thich hgp nhat trong 8 each thuc da che biin de theo doi sy thay ddi cic chit dinh dudng trong thdi gian bao quin tu 0 - 9 thing.
Cac cich thuc chl bien dugc su dung trong thi nghi?m la: Cdng thdc I (CTl): De ca la (di bd cuong) phai khd; cong thuc 2 (CT2):
D I ci Ii, ngam nudc, phai khd; cdng thiic 3 (CTS); Bam nhd la (2 - 3cm), phai khd; cdng thirc 4 (CT4): Bam nhd li, ngam nudc, phoi khd; cdng thuc 5 (CT5): Dl ca la, say khd;
cdng thuc 6 (CT6): Dl ca Ii, ngam nuac siy kho; cdng thuc 7 (CT7): Bam nhd Ii, siy khd;
cdng thdc 8 (CT8): Bam nhd la, ngam nudc, siy khd.
* Cdc chi tiiu theo doi:
Thdi gian phai, siy: Tvt khi bit dau phai hogc siy den khi li sin kho gidn, cd the bop vyn dugc.
Thanh phin hda hgc ciia BLS: Vit chit khd (VCK), protein thd, lipit thd, xg thd, din xuit khdng chua ni ta (DXKN), khoing tdng so, 19
Tran Thj Hoan vd Dig Tap chf KHOA HQC & CONG NGH$
HCN, fl caroten cua 8 cdng thirc Ihi nghi?m vi ciia BLS dugc bio quin d cic thdi diem: 0, 3, 6, 9 thing.
Phuong phip theo doi cic chi tieu li cic phuang phip thdng dyng dugc sir dyng trong nghien cdu chin nudi.
* Phirang phdp xu ly ket qua-. So liC'ii dugc xu Iy theo phuang phip thong ke sinh v§l hgc cua Nguyin Vin Thi?n (2002) [3].
KET Q U A V A B A N LUAN
Anh hurdng cua cich thirc che bicn den thdi gian phoi say l i siin
Sau khi thu hogch li sin, chung tdi tiln hinh che biin li sin theo 8 cich thuc di neu trong myc phuang phip nghien cuu. Ket qui theo ddi ve thdi gian phai ning, siy khd trinh biy tgi bing 1.
Sd lieu bing I cho thay khi phai ning thi can thdi gian de la san khd gidn dii hon so vdi say khd, thdi gian ciia 4 each thuc phai ning (CTl, CT2, CT3, CT4) Ii 261 phiit din 296 phut, cdn cua 4 each thuc say khd (CTS, CT6, CT7, CTS) la 128 phut din 189 phut.
De nguyen li (dii ngam nudc hoac khdng ngam nudc) thi thdi gian cin lam cho li khd gidn deu mat nhieu han so vdi bam nhd Ii (ngam nudc hoac khdng ngam nudc) d ci hai phuang phip phai va say. Thai gian phai doi vdi phuong phip dl nguyen ca Ii (cd ho§c khdng ngam nudc) tu 276 din 296 phut, cdn bam nhd la (cd hoic khong ngam nudc) tir 261 din 268 phiit. Tuang ty, de nguyen ca Ii,
Bing I: Thaigianphai
siy kho Ii 175 din 189 phut, cdn •m nhd la 128 din 133 phut.
Cic phuang phip cd su dyng ngam nudc phai mat it thdi gian hon so vdi khdng ngam nudc.
Thdi gian phai doi vdi phuang phip ngam nudc (de nguyen li ho$c bim nhd li) la 261- 276 phiit, cdn khdng ngam nudc li 268 - 296 phut. Tuang ty, thdi gian say cua phuong phip ngam nudc Ii 128-175 phiit, cdn khdng ngam nudc Ii 133 din 189 phiit. Sd dt cic phuang phip cd su dyng ngam nudc phai mit it thdi gian hon so vdi khdng ngam nudc la vl, khi dugc ngam nudc phan ldn nhya cua la sin da chiy ra ngoii nen khi vdt ra phai ning ho$c siy, hai nudc se thoit nhanh hon so vdi li sin khdng dugc ngam nudc. Ket qui cua chung tdi cung tuong ty nhu ket qua ciia Phgm Sy Tiep (1999)[4] khi phai sin cii thai lit cd va khong ngam nudc. Tuy nhien, ddi vdi cic phuang phap cd ngam nudc (ca phoi ho$c say) deu mat cdng sire, thdi gian hon cho vi?c ngam va de rao nudc.
Anh hud^g ciia cac each thdc che bien den thanh phan hda hgc cua la s§n Trong qua trinh che bien, dgc td HCN trong bgt la sin dugc logi bd nhung dong thdi ciing lam hao hyt cic chit dinh dudng trong la sin.
Chiing tdi da phin tich thinh phan hda hpc ciia BLS nham xac djnh anh hudng cua cac phuang phap che bien khac nhau den ham iugng cic chat dinh dudng trong BLS. Ket qui dugc the hien d bang 2.
ndng, say kho Id sdn (n =6)
Phuung phip che bien
Thdi gian phoi, say (phdt) (X±
m-
1 Decal4phcrikh6(CTl) 2 De ck Id, ngam nirdc, pliai kll6 (CT2) 3 B5m nho li phoi kho (CT3) 4 B5m nho 14, ngSm nudc, phoi kho (CT4) 5 De ca M, siy kh6 (CTS)
6 De c4 l&, ngiim nu6c, say kho (CT6) 7 Bam nho \i sSy kh6 (CT7) 8 Bam nho la, ngam nuoc, say kh6 (CT8)
296 ± 9,93 276 ±11,68 268 ± 10,21 261 ±11,37
189 ±6,34 175 ±6,16 133 ±7,35 128 ± 7,56
Tr k Thi Hoan vd Dtg Tap chl KHOA HOC & CONG NGH$ 92(04): 19-24
Sit 1 2 3 4 5 6 7 8
BSng 2: Thdnh phdn hod hoc >
Phirimg phdp ch^ bien DSca 14 phoi khe ( C T l ) De c4 14, ngam nudc phoi kh6 (CT2)
Bam nho 14 phoi kh6 (CT3) Bam nh6 14, ngam nudc, phai kho (CT4)
DS ca 14 sly khS (CTS) De c4 14, ngam nudc s l y khfi (CT6)
Bam nho 14 say kho (CT7) Bam nho 14, ngSm nudc s4y kho (CTS)
cua bdt id
VCK 90,76 90,31 90,29 91,06 90,87 90,86 90,40 91,36
sdn d cdc
Protein 22,84 22,29 23,01 22,80 22,67 22,71 22,78 23,32
phuangphdp che bien (n=3)
% trong vSt chat khd Lipit Xo- DXKN 8,32
8,90 8,36 8,52 8,45 9,12 9,04 9,28
13,68 13,75 13,80 13,89 13,55 13,70 13,47 13,65
46,29 46,95 46,43 46,50 47,34 47,30 46,90 46,71
Kho4ng 8,87 8,11 8,40 8,29 7,99 7,17 7,81 7,04 Ghi chu: DXKN: Ddn xudt khong dgm. VCK: Vgl chdt kho Bing 3: Hdm luang fi caroten vd HCN trong Id sdn a cdc cdch ihirc chi biin khdc nhau (n-3)
'V\
0 1 2 3 4 5 6 7 8
Thdi qu4n
Phirong phiip c h l biin
La san tuoi Dec414phcrikh6 De c414, ngam nudc, phoi kho Bam nho 14 phoi kh6 Bam nhd 14, ngam nudc phoi kho De ca 14, say khd
Di c414, ngam nudc, say khd Bam nho la, sly khd Bam nhd la, ngam nudc sly khd
B4ng 4. Thdnh phdn hoa hgc cua 1
do Protein
%
HCN (mg/kg
VCK) 1073,00 768,40 599,04 368,64 249,73 245,76 184,32 164,35 99,84
"" (.
100,00 71,61 55,83 34,36 23,27 22,90 17,18 15,32 9,30 bot Id sdn sau cdc thdi gian bdo.
trong vat c h i t khd Lipit Xff DXKN Kho4ng
fi caroten n g % VCK)
99,39 62,48 49,48 62,51 52,47 50,04 47,63 51,09 48,71 qudn (n=3)
P caroten (mg % VCK)
%
100,00 62,86 49,78 62,89 52,79 50,35 47,92 51,40 49,01
HCN (mg/kg VCK) Bit diu b4o qu4n 9,71 23,01 8,36
Sau3th4ng 10,17 21,77 8,31 Sau6th4ng 11,13 20,75 7,47 Sau 9 thang 13,42 19,62 5,95
13,80 46,43 8,40 62,51 368,64 14,24 47,19 8,49 32,32 291,07 14,82 48,27 8,69 12,11 210,02 15,52 49,95 8,96 0,00 147,38 Ghi
KSt qua bang 2 cho thdy: Khong cd sir khac biet cd quy luat giffa phai va say, de ca la va bam nho, ngam nui^c va khong ngam nirac ve ty 1? VCK, protein, xa. Ty le VCK dao dong tit 90,29 % - 91,36 %, protein trong VCK dao dong tir 22,29 % dta 23,32 %, xo trong VCK dao d§ng tir 13,47 % d6n 13,89 %.
Co sir khdc biet co tinh quy lu^t v6 lipit, khoang giffa khong ngam nudc va co ngam
chu: DXKN: Ddn xudt khong dam. VCK: Vdt chdi kho nirdc (doi vdi ca khong bam nho ho^c c6 bam nhd, phdi hoac say). Doi vdi ngSm nudc (du la de ca la, bam nho, phai, say), ty le lipit deu cao han so vdi khong ngam nudc. Cu the la:
Ty le lipit trung binh ciia cac cong thuc khong ngam nuijc (CTl, CT3, CTS, CT7) la 8,54 % con ciia cac cong thirc cd ngam nudc (CT2, CT4, CT6, CT8) la: 8,96 %. Ty I? khoang trung binh ciia cac cong thuc khong ngam
Trin Thj Hoan vd Dig Tgp chi KHOA HQC & C 6 N G N G H ^ nudc (CTl, CT3, CTS, CT7) Idn han so vdi
cic cdng thuc cd ngam nudc (CT2, CT4, CT6, CTS), tuong ung la: 8,27 % so vdi 7,65 %.
Li san siy khd (dii li dl ca Ii, hay bim nhd, ngam nudc hay khdng ngam nudc) deu cd ty I? DXKN ldn ban so vdi phai khd. Gii trj trung binh ve ly I^ DXKN ciia Ii sin d cic cdng thirc say (CTS, CT6, CT7, CTS) Ii 47,06
%, cdn cua cic cdng Ihuc phai (CTl, CT2, CT3.CT4)li:46,S4%.
Khi so sinh ve thanh phan hda hgc ciia hai phuang phip phai vi siy, khdng cd sy khic nhau ve VCK va protein. Tuy nhien, cung nhu vdi cii sin, vi^c siy khd li sin thudng phuc tgp va Ion kdm nen chi dung phuang phap nay de lim khd sin phim vio nhtfng ngiy mua. Vi vgy, trong thyc te sin xuat vdi khoi l u ^ g Idn, chiing ta nen su dung phuang phip phai khd dl giam chi phi va hg gia thanh sin pham.
Anh hvdng cua cac each thuc che bien den ham lirgng fl caroten va HCN trong bot la san
De biet dugc anh hudng cua cac cich thirc che bien den ham Iugng dgc to HCN vi fl caroten trong bgt la san, chiing toi da phan tich ham Iugng cua chiing trong BLS, ket qua dugc trinh biy d bang 3.
Sd lieu bang 3 cho thiy: Sau khi chl biin ham hugng HCN vi fl caroten deu giim nhieu so vdi la tuai, cy thi Ii: Ham Iugng HCN giim tir 28,39 % - 90,70 %, fl caroten giim td 37,14 % din 50,99 % so vdi la tuai. Cic miu bdt Ii san d phuang phip phai cd him lugng HCN va fl caroten cao hem so vdi say, gii trj trung binh ciia phuang phap phai (CTl den CT4) Ii 496,45 mg/kg VCK ddi vdi HCN;
58,49 mg % VCK doi vdi fl caroten, cdn phuang phip say (CTS den CTS) cd gii trj trung blnh la 173,57 mg/kg VCK HCN; cdn fl caroten la 49,37 mg % VCK. Kit qua cua chiing tdi ciing tuong ty nhu ket qua cdng bo ciia Pham SyTi?p (1999) [4].
Phuang phip bim nhd la (ca phai va say) deu lam giam HCN nhieu han de nguy6n li, nhung him Iugng fl caroten lgi cao han ddi 22
chiit. Cdn cic phuang phip nga fdc (ci phai va siy) lim giim HCN nhiei on so vdi khdng ngam nudc, nhung cung lam mat nhieu fl caroten hon so vdi khdng ngam nudc.
Trong cic phuang phip chl bien tren thi phuang phip bim nhd Id phai kho lim giim ding ke him Iugng HCN vi bio v? t6t him Iugng fl caroten trong bgt Ii. Day Ii dieu chimg ta mong muon khi ticn hanh che biin bgt li sin cho gia sue vi gia cam.
Anh htrdng ciia thdi gian bao quiin den c4c Ihiknh ph^n dinh dtrdng trong bgt 1^ sin Trong qui trlnh bio quin bgt li sin, ngoii dgc to HCN giim di, cic chat dinh dudng cung bj giim di, d$e bi?t li vitamin. De bilt dugc thinh phan hda hgc trong bgt la sin bien dgng nhu the nio sau cac thing bao quin, chiing tdi di phan tieh thinh phan hda hgc ciia bgt Ii sin dugc bio quan d eac khoang thdi gian: 0, 3, 6, 9 thing. Kdt qua dugc trinh bay d bang 4.
So lieu bing 4 cho thiy: Thdi gian bao quan cang dii thi am dg trong BLS cang tang, sau 3 thing bio quan, am dg ting 0,46 % nhung sau 9 thing thi am dg ting them tdi 3,71 % so vdi liic bat dau bao quin. nguyen nhan la do trong qui trinh bao quin, BLS da hut am tu khdng khi, dong thdi xay ra mgt so phan iimg hda hgc sinh ra nudc.
Protein vi lipit trong BLS sau 9 thing bao quan deu giam di so vdi liic bit dau bao quin, cy the: protein giim tu 23,10 % xudng 19,62
% (giim 3,48 %), cdn lipit giam tu 8,73 % xudng 5,95 % (giim 2,78% so vdi luc bit dau bao quin). Sd dT ham Iugng protein va lipit giam Ii do am dg ting Ien thi him lugng VCK giam, din den cic chat dinh dudng trong thuc in bj giam xuong, mit khac trong thdc an protein va lipit chju tac dgng rit Idn ciia sy oxy hda nen protein va lipit se giam khi ting thdi gian bao quan. Xo, DXKN, khoang ting theo thdi gian bao quin, cy the:
xa tang 1,77 %; DXKN tang 3,94 %, khoang tang 0,54 %. Xa, DXKN, khoang tang cd thi do trong 1 OOg VCK ciia thuc an, ty 1$ mgt sd chit nay giam di (protein, lipit) thi cac chit cdn lgi se ting Ien.
Trin Thi Hoan vd Dtg Tgp chl KHOA HQC & CONG N G H ? 92(04): 19-24 Him Iugng HCN giim td 368,64 mg/ kg
VCK (bit diu bao quin) xudng cdn 147,38 mg/ kg VCK (sau 9 thing). Tie gia Duang Thanh Liem (1998) [2] khi nghi8n cdu ve bao quin bgt la san, cung thdng bio ve sy giim ham lugng HCN tuong tu nhu kit qui nghien CU'U cua chiing tdi.
Him lugng fl caroten trong bgt Ii sin luc bit diu bao quan la: 62,51 mg % VCK, sau 3 thing cdn: 32,32 mg % VCK, giim 48,30 % so vdi lue bit dau bio quin, sau 9 thing bao quan thi fl caroten hau nhu khdng cdn. Tic gia Duong Thanh Liem (199S) [2] cho bilt ham lugng fl caroten trong BLS giim nhanh theo thdi gian bio quan, thi nghi?m ciia chiing toi cung cd kit qui tuong tu.
Cic chat dinh dudng va fl caroten giam nhanh trong qua trinh bao quin, vi vay neu BLS da dugc bio quan lau mdi dua ra su dung lam thuc an cho vat nudi dgc biet la cho
gia cam thi se inh hudng rit Idn den khi nang sinh trudng doi vdi gi thjt vi sin xuit trirng, dii vdi gi sinh san.
Anh hudng cua thdi gian bSo quan den cac amino acid trong BLS
Kit qui nghien cuu bang S cho thay: Sau 3 thing bio quan tat ca cac amino acid thiet ylu vi khdng thiet yeu deu giim dang kl, ty I?
hao hyt cic amino acid tir 2,23 % -51,28 %.
Trong dd, amino acid arginine cd ty I? hao hyt ldn nhat (51,28 %), cac amino acid cd ty Ie hao hyt ldn thu 2 (tren 40 %) la leucine, tyrosin, lysine. Da so cac amino acid cd ty ie hao hyt tren 30 %, amino acid cd ty Ie hao hut it nhat la aspartic (2,23 %).
Nhu vgy, ham Iugng cic amino acid trong bgt Ii sin giim di khi nhanh theo thdi gian. Dieu dd cho thay bdt la san can dugc su dung ngay sau khi che bien, khdng nen bao quan lau dai.
Bang 5. Hdm luang cdc amino acid Irong protein cua Id sdn sau thdi gian bdo qudn T£n amino acid Bat dau b i o
quan fe % ) (A)
Sau 3 t h i n g (g%)
(B)
T J If hao hut, B so vdi A (%) 1
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Lysine Methionine Phenylalanine Isoleucine Leucine Histidine Glycine Threonin Arginine Valine Glutamic Serine Alanine Tyrosine Aspartic Proline
7,46 2,49 3,99 7,24 9.74 0,74 5,35 5,57 6,65 5,55 12,23 3,50 7,49 4,79 10,33 5,73
4,36 2,10 2,64 5,61 5,57 0,61 3,47 4,42 3,24 3,68 8,25 2,35 4,65 2,74 10,10 3,87
41,55 15,66 33,84 22,51 42,81 17,59 35,14 20,65 51,28 33,69 32,54 32,86 37,92 42,80 2,23 32,46
Tran Thj Hoan vd Dtg Tgp chf KHOA HQC & CONG NGH$
KET LUAN
siy khd la sin cd nhieu uu diem hon Ii phoi, nhu: Thdi gian lim khd nhanh hon, bio ton dugc cic chat dinh dudng, logi bd dugc nhieu dgc to, chi cd fl caroten bi hao hyt nhieu han so vdi phoi, Tuy nhien, trong dieu ki?n d nudc ta hi?n nay, chl bien bang phuang phip siy vdi khoi lugng Idn Ii chua phii hgp.
Phai Ii sin bing cich bim nhd Ii (ngam nudc hoic khdng ngam nudc trudc khi phoi) di riit ngin dang ke thdi gian phoi, bao ton dugc cic chat dinh dudng va fl caroten tot hon, logi bd dugc nhieu dgc to hon so vdi de nguyen Ii (ngim nudc hoic khdng ngam nudc), nen ip dyng phuang phap nay trong sin xuat bgt li sin.
Bgt Ii sin sau thdi gian bao quin 3 thing di giim 10 % protein, 15 % lipit, 46 % fl caroten. 2,23 % -51,28 % amino acid vi sau 6 thing da giam di 20 % protein, 27 % lipit, 88
% fl caroten. Vi vgy, sau khi che bien, can
dua bgt li sin vao su dyng nga: ''^"S "^^
bio quin bgt Ii sin qui liu.
TAI LI$U THAM KHAO [1], Nguyin Khic Khdi (1982), "Sir dyng b^t Ii sin chin nudi Ign", KHKT Vi4n chdn nudi Hd Ngi T4, tr53-55.
[2]. Duong Thanh Li6m, NguySn Phiic L^c, Nguyin van Hio, Ngfl Vin Min, Bui Huy Nhir Phiic, Bili van An (1998), "Chl biin vi sir dyng bdt li khoai mi trong chin nudi gia sue", Chuang irinh .sdn Viil Nam hudng lai ndm 2000, Hpi thao sin Vi^tNam.
[3]. NguySn Van Thi^n, Nguyen Khinh Quic, NguySn Duy Hoan (2002), Gido trinh phuang phdp nghien cuu trong chdn nudi, Nxb Ning nghiep Hi Ndi.
[4]. Phgm sy Ti^p (1999), "Nghien ctm gii trj dinh dudng ciia mdt so gilng sin d trung du vi miin niii phia Bic, inh hudng cua phucmg phip chl biin din thinh phin hda hpc ciia cii, li vi khi nang sir dyng bdt sin dl v5 b^o Ign FI (DB x MC)", Lugn dn liin si Nong nghiip, tr 29.
ABSTRACT
THE EFFECTS OF PROCESSING METHODS ON DRYING TIME AND CHEMICAL COMPOSITIONS OF CASSAVA LEAF MEAL
Tran Thi Hoan*, Tu Trung Kien College of Agriculture and Forestry - TNU Wetested eight different methods of processing cassava leaves, the results are as following:
Drying cassava leaves by electronic power (oven, electric oven), has more advantages such as: less time to dry, less loss of nutrients and carotene, most decrease in toxin HCN. However, in current condition of our country, this method may not be widely applicable.
Cuning leaves into small pieces, specially soaking them into water before drying significantly reduces drying time, better conserves nutrients and carotene and eliminates more toxins than the other methods. Therefore, this method should be applied in the production of cassava leaf meal.
Nutrients and carotene decrease rapidly during storage. After 6 months of storage, protein, lipids and p-carotene decrease 20.00 %, 27.00 % and 88.00 % respectively. Therefore, cassava leaf meal should be used immediately after processing and not being stored for too long.
Keywords: Casaava leaf meal, processing methods, drying lime, chemical compositions
Ngdy nhdn: 12/3/2012 . Ngdy phdn biin:20/4/2012. Ngdy duy4t ddng: 14/5/2012
