TIIMH CHE V A DAIMH E l A CHAT LLTQIVG D A U CLIA H A T CAY CHE XAIXIH [Camellia sinensis v a r . sinensis
TRDIMG D P H U THD
Nguyin Duy Lam\ Nguyin Quang D u e \ Vu Due Chien^
TOM TAT
Cac cong doan quan trong trong qui trinh tinh che diu tho trich ly tir hat cay che xanh trong a tinh Phu Tho da dugc nghien cuu. Trong cong doan diu tien la xir ly nhay, da xir ly dau tho voi H3PO4 a cac nong do 0,1-0,5%. Ket qua cho thay nong dp H3PO4 0,3% co hieu qua xir ly tdt nhat voi ham lugng can thap la 2,30 g/100 g diu. Ket qua nghien cuu cong doan thuy hoa da chi ra nhiet do va thuy phan tdi uu cua qua trinh lan lugt la 50°C va 3% voi hieu suit tach phdt phat dat 83,9%. Nghien ciiu cong doan trung hoa dau dugc thuc hien voi NaOH a cac nhiet do khac nhau da chi ra ring nhiet dp 60°C va nong dp NaOH 130 g/1 cho ket qua trung hoa diu tot nhat. Trong cong doan cudi ciing la tay mau, da sir dung dat va than boat tinh voi ty le va nhiet dp khac nhau. Ket qua cho thay nhiet dp tay mau 100''C, ti le dat 1%, ti le than 0,5% cho ket qua tay mau tot nhat doi voi cac mau dau hat che. Dau sau tinh che da dugc xac dinh cac chi tieu hoa ly, thanh phan cac axit beo va mot so tinh chat chat lupng cam quan. Cac so lieu thu dugc cho thay chat lugng diu hat che xanh Phii Tho la tuong duong voi cac san pham ciing loai do Trung Quoc san xuat.
Tir khoa: Dau hat che, thanh phan, tinh che, tinh chat I.DATVAniDE
Cay chi xanh (Camellia sinensis var. sinensis) khOng thudc nhdm cay lay diu nhung ty le dau trong hat rat cao. Diu hat c h i cd gil tri dinh duong ldn II do chira nhilu d c axit beo kh6ng no, trong dd nhilu nhlt II axit oleic (chiim tir 40- 60%) (Xia et al, 1993;
Ruter, 2002). Trong dau hat e h l cdn cd mdt lugng ding k l d c vitamin vl d c chat chdng 6xy hoi, dac biet diu hat che kh6ng chira colexteron. Uu diem ndi bat cua diu hat che II co nhiet do phan buy cao hon bin so vdi d c loai diu an th6ng thudng khIc, do do it bi biin ddi trong qua trinh che bien nhiet. Diu hat che ed miii vi thom nhe, de bio quIn vl cd t h i giQ dugc dn dinh chit lugng trong thdi gian dii (Sahari et al., 2004). Vdi nhirng uu diem neu tren, diu hat che dugc sin xult vl tieu thu phd biin vdi lugng ldn d nhilu nude, dac biet d Trung Qudc vl An Dd (Xia et al., 1993). Nude ta cd tilm nang v l nguyen lieu hat ehl diing cho sin xult diu, nhung hien nay vIn chua dugc nghien cuu vl khai thIc hieu qui. Chinh vi vay, chua cd d c thOng tin ve thinh phan, tinh chit va qui trinh c6ng nghe tinh e h l diu hat c h i trdng trong nude.
Mue tieu ciia nghien cim nly II khIo sit mot sd e6ng doan quan trgng cua q u i trinh tinh e h l d l tao diu hat che thinh pham vl d i n h gil chat lugng diu d d c e6ng doan tuong ung dd.
II. VAT UEU VA PHUONG PHAP
1. Vat heu
Hat che dugc thu tir d e cay e h l xanh (Camellia sinensis var. sinensis) trdng tai nhilu ddi e h l thuoc Doan Hiing, Phii Thg. Lugng hat che dimg cho thi nghiem II 300 kg duge sly d i n do Im 10-12%, bio quIn trong dilu kien kh6, thoing cua phdng thi nghiem.
2. Phuang phap trich ly dau
Trich ly theo qui trinh: Hat che —> Say —» Bd vd hat —>• Bio quin —>• Nghien -^ Sang, ray -^ Trich ly -^ Lgc —y Diu hat che thd. Cac th6ng sd quan trong bao gdm: Kich co' hat: 1 mm < d < 2 mm; dung m6i: n- Hexan; tdc dd k h i y trgn: 360 vong/phiit; ty le dung m6i: 2 / 1 ; nhiet do trich ly: 60''C; thdi gian trich ly: 4h.
Qui trinh nly dugc thuc hien theo Rajaei va ddng tic gia (2005).
^ Vien Co dien Nong nghiep vS Cong nghe Sau thu hoach
" Vien Cong nghiep Thuc phIm
3. Phuang phap tmh che dau
Tinh e h l diu hat che theo qui trinh sau (Vu Thi DIo, 1997): Diu thd -^ Xu ly nhiy-* Thiiy hda -*
Trung hda — Rua diu -> Say diu -> Tay mim - , Khu
miii-^ Diu tinh che thinh pham. Tiln hanh nghien ciru tinh c h i theo qui trinh nly va tap trung vao cac cong doan xtr ly nhly, thuy hoa, trung hda va fly mau.
4. Phuang p h i p phan tich v l d i n h gil chat lugng diu
- Tien hinh lly miu diu theo TCVN 2625 - 78.
- Xlc dinh do Im va ham lugng cac chat bay hoi theo TCVN 6120:1996 (ISO 662:1980).
- Xlc dinh chi sd axit ciia diu theo TCVN 6127 - 1996.
- Xlc dinh chi sd peroxyt eiia diu theo TCVN 6121 - 1996.
- Xlc dinh chi sd iot cua diu theo TCVN 6122:1996 (150 662:1980).
- Xac dinh chi sd x l phdng cua dau theo TCVN 6126:1996 (ISO 663:1992).
- Xlc dinh h i m lugng phdt phIt theo theo c6ng thirc:
( G 1 - G 2 ) .
P = -100%. Trong dd Gl: trgng lugng cdc chiia phdt phIt da sly kh6 (g); G2: trgng lugng cdc (g); G: trong lugng miu (g).
- Xac dinh chi sd tieu hao diu theo c6ng thue: t C — C
= — — %. Trong dd t II chi sd tieu hao diu;
^JA ~ All,
G^b II trong lugng dau dua vIo trung hda (g); G^th Jl trong lugng dau sau khi trung hda (g); A^b II chi sd diu tho dua vIo trung hda (mg KOH/g); A^th H chi sd diu th6 sau khi trung hda.
- Xlc dinh hieu suit thu hdi diu theo e6ng thire: H = (G-GJ/G X 100%. Trong dd: G II trgng lugng diu trudc khi tinh c h i (g), GQ II trgng lugng diu sau tinh chi (g).
- Xac dinh thinh phln axit b i o trong diu theo phuong phip AOCS Cele - 91 b i n g mIy sic ky khi GC Plus 6890 HP tai Vien Nghien cuu Diu v l Cay ed diu.
- Xlc dinh chi sd miu ciia diu theo thang dilm miu tieu chuan TCVN 2627 - 78.
- Xir ly sd lieu thdng ke vdi phln m l m IRRISTAT 4.0.
III. KET QUA VA THAO LUAN
1. Kit qua xac dinh chat lugng dau hat che tho
Da xlc dinh dugc h i m lugng diu la 12-14%. Mot sd chi tieu chit lugng diu hat e h l th6 dugc trinh bay trong bing 1. Kit q u i cho thIy diu hat che cd chi sd axit 4,5 mg KOH/g, chi sd peroxit II 4,2 meq 02/kg va chi sd phdt phIt II 1,2%. So voi d c loai diu th6 th6ng thudng thi chit lugng diu hat e h l th6 cung tuong duong (Vu Thi DIo, 1997).
Bang 1. Chat lugng diu hat e h l th6 TT
1 2 3 4 5
Chi tieu D6 am Axit Peroxit Phosphatit Miu sic
Gil tri 4,5 mg KOH/g diu
4,2 meq02/kg diu 1,2% / d i u VIng nau 2. Kit qua xu ly can va nhay bang axit H3PO4 Trong diu tdn tai c l hai loai II phospholipit kh6ng hidro hda v l ed k h i nang hydro hda. Diing H3PO4 de xu ly diu tho n h l m loai bd cle phospholipit kh6ng hidro hda v l elc chit khIe (Szemraj, 1974). Da tiln h i n h xir ly diu tho vdi H3PO4 d d c ndng do tir 0,1% d i n 0,5%. Kit q u i thuc nghiem (bang 2) cho thay voi lugng H3PO4II 0,1% thi can d dang huyin phii, la limg, khd tach, lugng can thu dugc thIp, chi dat 1,75 g/lOOg diu. Khi ty le H3PO4 tang len 0,2% thi lugng can thu dugc tang 24%
dat (2,17 g/lOOg dau). Khi h i m lugng H3PO4 tang len 0,4%, hieu suit tich can tdt nhung diu hi sIm miu ddng thdi chi sd axit tang len. Do vay, ndng do axit H3PO4 0,3% cd hieu qua xir ly tdt nhat vdi h i m lugng can thu dugc dat 2,30 g/lOOg diu. Viec xii ly nly lien quan d i n sy phan huy protein, can v l elc san phIm oxy hda chat beo, p h i buy cau tnic elorofil, pheophytin thinh d c d i n xuat hda tan trong nude, fly trir mdt lugng ldn oxit kim loai giiip cho viec loai trir cle phospholipit khong hidro hda duge d l ding.
Nhd c6ng doan nly cd t h i giam duge tdi 30% nguyen lieu trong khau tay miu v l diu thu duge cd chit lugng tdt hon v l chdng chiu dugc su oxy hda
(Szemraj, 1974; Sahari et al, 2004).
Bang 2. Anh huong ciia ty le axit H3PO4 d i n chat lugng dau
TyleH3P04 (%) trong diu
0,1 0,2 0,3 0,4
Chi sd axit (mg KOH/g)
5,70="
5,95'' 6,35<^
6,87''
L u g n g can (g/lOOg d i u )
1,75^
2,17'' 2,30^
2,48-^
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 4 - THANG 4/2010 35
3. Kit qua nghien cim e h l do thuy hda dau Diu II dung moi kh6ng phan cue nen cd t h i hda tan mot sd chit kh6ng phan cue hoac phan cue ylu.
Thuy hda II phuang phap diing nude ndng tang cudng cac phan img hidrat hda tic ddng llm cho d c hgp chit khong phan cue trd len phan cue manh do dd tach khdi diu va chuyin sang hda tan trong nude.
Mot trong nhung chit hda tan trong diu d n tach la cac phdt phat, day la mot loai lipit phuc tap trong dd cd gdc ciia axit photphoric va mot baza nita khi tham gia phln ung hidrat hda se tao thinh lexithin ngam nude phan cue manh. Nhd vay dimg phuong phip thuy hda cd thi tach dugc d l ding (Vu Thi DIo, 1997; Ataii, 2003).
Tiln hanh thiiy hda diu d d c nhiet dd khac nhau til 30-65"C vdi lugng nude thiiy hda tir 1-6%. Sau dd tiln hinh xlc dinh hieu suit tich phdt phlt. Kit
A n h huang cua nhiet do thuy hoa
qua (hinh 1) cho thIy nhiet do tang thi hieu suit tich phdt phlt tang. Cu t h i khi tang nhiet do tix 40°C len 50^0 hieu suit tach phdt phlt tang tir 71,7% len 82,2%
(tang 14,5%). Tuy nhien nhiet do tang q u i cao llm cho can ling nhanh chua du d l r i n lai do dd ndi nhilu tren b l mat diu rlt khd tach ra khdi diu nen hieu suit tach phdt phat lai gilm. Nhiet do tdi uu cho qua trinh thuy hoa la 50"C. Cung theo k i t qua tir hinh 1 khi tang lugng nude thuy hda tir 1% din 3%
hieu suit tach phdt phat tang 6,6% (tir 78,7% din 83,9%). Dilu nly co t h i giii thich la do lugng nude tang llm tang lugng tic nhan phan ling, tang tilp xiic nen lugng phdt phlt tach dugc tang. Tuy nhien, lugng nude tang vugt nguong llm cho can thu dugc d dang huyIn phii khd tich v l nude d trong diu nhilu llm Inh hudng xau d i n diu. Kit q u i nghien ciru cung cho thay lugng t i c nhan thuy hda tdi uu II 3%.
i
Anh hiroTig cua \utQing nwoc thuy hoa ;
•^ 7 6
(/I
S 73
Q.
.c O a.
I
40 50 60
Nhiet dp thuy hoa (°C) Luang nwac thuy hoa (%)
Hinh 1. Anh hudng ciia nhiet do (trai) v l lugng nude thuy hda (phai) tdi hieu suit tach phdt phat 4. Kit qua nghien euu c h i do trung hda dau
Diu th6 sau khi trich ly co lugng axit ldn tdn tai dudi dang tu do, d c axit beo nly nlu kh6ng dugc tich ra thi trong q u i trinh bao quIn diu se thiic dly qui trinh thiiy phan, 6i hda llm chit lugng diu gilm.
Do dd cin phii trung hda diu, dua chi sd axit vl tieu chuln. O phln img trung hda cdn diln ra q u i trinh loai bd d c phdt phlt, chit nhua, chit miu do x l phdng cd khi nang hap phu d c chat nly khi k i t tua.
Vi vay sau trung hda, chi sd axit eua diu thIp, miu sac vl chit lugng diu cung tdt hon (Ataii, 2003;
Sahari, 2004). Tiln hinh trung hda dau vdi NaOH trong khoing 110-150 g/1 v l nhiet dd trung hda 50- 70°C. Kit qua (hinh 2) cho thIy nhiet dd trung hda
llm tang tdc do phan ung, do dd tang hieu suit loai bd axit b i o tu do trong diu. Kit qua cung cho thIy, nhiet do trung hda d n g tang thi lugng axit bio tu do trung hda dugc d n g nhilu do dd chi sd axit d n g gilm. Tuy nhien, song song qua trinh dd lai II su tang len ciia chi sd tieu hao diu. Mat khIe nhiet do phan ung n l u tang q u i eao se lam cho can x l phdng ndi nhilu v l diu hi sIm miu dac biet gay khd khan cho qua trinh ly tam tich can x l phdng. Nhiet do trung hda 60°C cho k i t qua tdt nhlt. Cung theo kit q u i tir hinh 2, nlu sir dung kilm trung hda vdi ndng do thIp q u i thi kh6ng du phan ung. Ngugc lai, neu sir dung vdi h i m lugng q u i cao thi chi so tieu hao diu tang nhilu vl tdn mot lugng kilm cho phan ung tang len. Ndng do kilm trung hda la 130 g/1.
C h J s 6 a x i t ( r n g K O I - l / Q )
O 5 5 O.SO
0 . - 4 5 !g^
0 . - 4 0 0 . 3 S • 0 - 3 0 O 2 5 o 2 0 0 . 1 s
- C h . sd) l i d u h o o d i u
55 eo es
r s l h i ^ t ( 3 0 t r u r t g h d a ( " C )
C h i s 6 a x i t ( r r t g K O H / g ) 0 5 5 0 5 0 0 -4 5 0 4 0 0 . 3 5 0 3 0 0 . 2 5 0 2 0 G 1 5 • 0 1 0
Jkr
1 1 c
y^—
^^^--^ an Cl-ns6a>iil
MS.
1 2 0 13Q 1 4 0 r4&ng dO N a O H ( g / l )
C h i
.^—^
^ie 1 5 0
1 4 0 1 3 5 1 3 0 1 . 2 5 1 2 0
• l i s 1 1 0
Hinh 2. Anh hudng cua nhiet do (trii) va ndng do Bang 3. Anh hudng cua nhiet do tay miu tdi
chat lugng diu STF
1 2 3 4 5
Nhiet d6
ec)
90 95 100 105 110
Dd miu ciia diu (mg I2 /100ml)
6^
4"
3"
3'^
4b
Ghi chii: Cic sd lieu theo cot cd chu sd mii khIc nhau la cd gil tri khIc nhau cd y nghia d mirc y nghia a=5%
Bang 4. Anh hudng cua ty le dlt/than den do miu cua diu
Ty le trong diu (%) Dlt
1,0
1,5
2.0
Than 0,5 1,0 1,5 0,5 1,0 1,5 0,5 1,0 1.5 0,5 1,0 1,5
Do miu cua diu (mg I2 /100ml)
13,1"
13,4"
13,5"'' 13,2"
13,4"
13,5*
13,5"'' 13,7""
14,0'' 14,0'' 14,2'' 14,4"
Ty le tieu hao diu (%)
7"
5"
5"
3"
3"
2"
4"
5"
yd 6-^
7"
yd
kilm (phai) d i n chi sd axit v l tieu hao cila diu
DIo, 1997; Ataii, 2003). Tiln h i n h thi nghiem vdi nhiet do tly miu 90-105*'C vl ty le dat/ than khIe nhau. Kit q u i dugc trinh bIy trong bing 3 vl 4. Kit qua (bing 3) cho thIy khi tang nhiet dd fly miu tir 90°C len 105''C thi miu sic ciia diu dugc d i thien ro ret. Do miu ciia diu giam tir 6 mg 12/lOOml xudng 3 mg I2/100ml. Tuy nhien, khi vugt qua 105°C thi miu sic ciia diu lai tang len. Dilu nly cung d l hieu vi diu se bi bien ddi khi d nhiet do cao trong thdi gian tay miu tuong ddi dii. O nhiet do llO^C, do miu ciia diu II 4 mg 12/lOOml. Kit q u i bing tren cho thIy, nhiet dd tly mau tdt nhat II 100°C-105°C.
Dlt va than boat tinh cd tic dung h i p phu d c phln tu mau llm cho miu sic diu sing len. Theo k i t q u i thuc nghiem (bang 4) thIy ring ty le dlt/than (%
diu) d n g eao thi q u i trinh h i p phu miu d n g tdt. Cu t h i khi tang ty le d l t / than (tinh theo % so vdi diu) II 0,5-0,5 len 1,0-1,5 thi miu sic eua diu dugc cai thien ro ret. Do miu cua diu gilm tir 7 mg Ij/lOOml xudng 2 mg 12/lOOml. Tuy nhien, khi tang lugng dat va than se llm tdn hao diu d n g ldn va d n g tdn lugng chat h i p phu. Nhu vay chi phi san xult se tang len. Tir k i t qui nghien cuu tren, nhan thIy ti le dlt 1% ciing voi than boat tinh 0,5% cho k i t q u i tdt.
Bang 5. Cac ehi tieu hda ly eiia dau hat che Doan Hiing
5. Kit qua nghien euu e h l do tay mau
Tay mau II c6ng doan cudi ciing cua qua trinh xir ly diu tho. O c6ng doan nly sir dung q u i trinh hip phu ddi vdi d c chit miu nhu chlorofil, carotenoid giiip cho diu hat e h l dat dugc miu sic yeu clu. Trong e6ng nghiep, thudng su dung than hay dlt boat tinh de thyc hien qua trinh nly (Vu Thi
Chi tieu Miu sic, do sing FFA
Dd Im vl chat bay hoi
Tap chit Chi sd peroxit Chi sd iot Chi sd x l phdng
Don vi do Mg I2/100ml
Mg KOH/g
%
% meq 02/kg diu
gl/lOOg mg KOH/g
Gil tri 3 0,15 0,03
<0,05 1.5 86 184
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 4 - THANG 4/2010 37
Bang 6. Thinh phln axit bio eiia diu hat che Chi tieu
Axit oleic (0,8.,) Axit linoleic (C18.2) Axit linolenic (Cig.j) Axit eicosenoic (C201) Axit myristic (C14-0) Axit palmitic (C150) Axit palmitoleic (C,6.i) Axit margaric (Ciyo) Axit stearic (C,s.o)
Gil tri {%) 44,13 27,79 0,79 0,58 0,16 20,46
0,34 0,15 5,60 Bang 7. Chat lugng cam quan cua diu hat che Chi tieu
Miu sic Miiivi Trang thii Tdng diem
M o t I
Vang sing hoi xanh dac trung
Miii tham dac trung, hoi bio, ngii
Trong, sanh, ddng nhlt
Gia tri 5 4 5 14/15 6. Dinh gil chat lugng dau hat e h l sau tinh e h l Sau khi tinh c h i diu hat ehl, da tiln hanh dinh gia chit lugng diu thanh pham. Kit qua thu duge (bang 5) cho thIy cac chi tieu hda ly cua diu hat che sau tinh e h l rlt tdt. Miu sic dat 3 mg Iz/lOOml, tap chit
< 0,05%. Cac chi sd peroxit, chi sd iot, chi sd x l phdng tuong ung II 1,5 meq 02/kg diu; 86 gl/lOOg vl 184 mg KOH/g. Cic ehi tieu nly deu thuoc nguong rat thIp.
Kit qua cung cho bilt d c chi tieu hda ly cua diu hat che sir dung trong thi nghiem nly sau tinh e h l cung tuong duong voi diu hat e h l cua t h i giai.
Diu hat chi thuong mai C6ng ty Shanghai YongSun Foods Co.Ltd vl C6ng ty China Color Tea Co., Ltd (Trung Qudc) dang chio ban tren thi trudng ed d c ehi tieu hda ly nhu sau: Miu sic, do s i n g Y < 35; R <
3,5; FFA < 0,20 mg KOH/g, do am v l d c chit bay hoi < 0,05%, tap chit < 0,05%, ehi sd peroxit < 5 mmol/kg, chi sd iot 83-89 gl/lOOg, chi sd x l phdng 180-188 mg KOH/g (Xia et a l , 1993).
Bang 6 cho thay diu hat e h l Viet Nam cd chua d c axit bio omega 9 dat 44,13%; axit omega 6 dat 27,79% vl omega 3 dat 0,79%. Day la cae axit beo dugc su dung rong rai trong thue phIm, thuc phIm chuc nang, duge pham vl hda my pham. Do vay viec nghien cuu cong nghe khai thIc vl tinh c h i diu hat che se gop phln nang cao gil tri ciia cay c h i Viet
Nam trong tuong lai. Kit q u i cung cho Hi >: ve mat dinh duong (bing 6) va d m quan (bang 7) thi chat lugng diu hat che Viet Nam cung tuong duong vdi elc sin phIm thuong mai cua t h i gidi. Mot san pham dau hat che thuong phIm dugc chao bin cua hang Zhejiang Choisun Tea Development (Tmng Qudc) cd thinh phln la: Axit bio no 12-18%, axit oleic 57- 62%; axit linoleic 21-25%, axit linolenic 1-3%, polyphenol 1%, vitamin E 159-200 mg (Xia et al., 1993).
IV. KET LUAni
Da xac dinh dugc cac thong sd c6ng nghe co ban cua q u i trinh tinh e h l diu hat c h i Phu Tho. Do la xii' ly nhly b i n g H3PO4 0,3%, thuy hoa vol lugng nude 3% d nhiet do 50''C, trung hda diu voi NaOH 130 g/1 d nhiet do II 60°C, fay miu vdi ty le dlt va than boat tinh hrong ung la 1 vl 0,5%. Da xlc dinh dugc cle ehi tieu chit lugng ciia dau hat e h l thinh pham. Cu thi: miu sic, do sing 3 mg Iz/lOOml, FFA 0,15 mg KOH/g, do am vl d e chit bay hoi 0,03%, tap chit < 0,05%, ehi sd peroxit 1,5 meq 02/kg, ehi sd iot 86 gl/lOOg, chi sd x l phdng 184 mg KOH/g. Cle ehi tieu chat lugng ciia diu hat che Phii Thg sau khi tinh c h i II holn toln tuong duong vdi chit lugng diu hat che do Trung Qudc san xult. Cle thinh phln axit beo trong diu hat che Phii Thg thinh phIm gdm:
oleic 44,13%, linoleic 27,79%, hnolenic 0,79%, eicosenoic 0,58%, myristic 0,16%, palmitic 20,46%, palmitoleic 0,34%, margaric 0,15%, stearic 5,60%. Nhin chung, thinh phln v l ty le giira d c thinh phln axit beo trong diu hat che Phii Thg II phii hgp vdi d c san phIm diu hat che da san xuat vl thuong mai cua T m n g Qudc.
TAI UEU THAM KHAO
1. Vu Thi DIo (1997). Gilo trinh cOng nghe diu thue vat. Trudng Dai hgc Nong nghiep HI Ngi.
2. Ataii D., Sahari M. A., Hamedi M. (2003).
Some Physiochemical characteristics of tea-seed oil.
J. Sci. & Technol. Agriculture and Natural Resources, 7(3), 183-183.
3. Crevegos J. (1995). Physical refining of edible oil. Journal of Americal oil Chemist's Society, 72, 316- 368.
4. Rajaei A., Barzegar M. and Yamini Y. (2005).
Supercritical fluid extraction of tea seed od and its comparison with solvent extraction. Europe .n Food Research and Technology, 220(3-4), 401-405.
5. Ruter J. M. (2002). Nurseiy production of tea antioxidant. / of the American Oil Chemists Society, oil camellia under different light levels. In: J. Janick 81(6), 72-78.
and A. Whipkey (eds.), Trends in new crops and new 7. Szemraj H. (1974). Effect of phosphoric acid uses. ASHS Press, Alexandria, VA: A/neryca/? 5 c i a e ^ on the colour change of rapeseed oil (in Polish).
for Horticulhiral Science Press pp. 222-224. Tluzeze Jadalne, 18(3), 13-17.
6. Sahari M. A., Ataii D., Hamedi M. (2004). 8. Xia, L, Zhang A. and Xiao T (1993). An Characteristics of tea seed oil in comparison with introduction to the utilization of camellia oil in China, sunflower and olive oils and its effect as a natural Am. Camellia Yearbk. 48,12-15.
REFINING AND CHARACTERIZING OF EDIBLE OIL EXTRACTED FROM PHU THO GREEN TEA SEEDS (Camellia sinensisvai. sinensis)
Nguyen Duy Lam, Nguyen Quang Due, Vu Due Chien Summary
The most important processing stages of tea-seed oil refining were investigated for the popular Vietnamese green tea (Camellia sinensis var. sinensis) cultivating in Phu Tho province. In the first stage - treatment of slimy substances - the crude oil was treated with H3PO4 at concentration arranging from 0.1 to 0.5% in oil.
The results showed that 0.3% H3PO4 has the best treating effectiveness with low residue of 2.30 g/100 g oil remained. The investigation of the second stage - oil liquefying - showed the optimal temperature and water content were 50°C and 3%, respectively with productivity of phosphatic separation reached 83.9%. The oil neutralization was carried out with NaOH at different temperature and has indicated OO^C and 130 g/1 NaOH is the best condition for best neutralization. In the last stage of oil refining - oil bleaching, the activated earth and coal were utilized. The results of this investigation showed the best bleaching can be gained at 100°C with percentage of activated earth and coal were 1% and 0.5% respectively. The refined oil has been determined for physiochemical characteristics, fatty acid components and sensorial properties.
The received data showed their similary to those of commercial Chinese tea-seed oil products.
Keywords: Tea-seed oil, reiining, characterizing, physiochemical properties, fatty acids.
Ngudi phan bien: PGS. TS. Ngo Xuan Manh
NONG NGHIEP VA PHAT TRIEN NONG THON - SO 4 - THANG 4/2010 39