OANH GIA CHAT LU'ONG CUA T R A NU V6l DU'OI NHIEU H I N
i iTHAI VA CACH PHACHE THD'
TriroTig Tuyet M a i , TruoTig H o a n g Kien*, Nguyen X u a n Ninh Vien Dinh duffng Quoc gia, Hd ngi
* Chi cue ve sinh an todn thuc phdm Qudng Ninh, Viet Nam
TOM TAT
Nu vdi do'pc chd bidn theo 3 dang hinh thai hat khac nhau, ddng gdi 2 g nu V6i/gdi. Tra nu Vdl sau khi du-gc pha chd du-dl dang dun sdi va pha ham nu'dc soi trong thdi gian khac nhau, tidn hanh danh gia cam quan va xac dinh ham lugng polypenol trong nu'dc tra nu Vdi thu dwgc. Kdt qua cho thay, ham lu-ang polyphenol thet tach td tra nu Vdi dang nhd hat dat cao nhit, va ham lugng polyphenol theo each dun sdi cao han so vdi each ham nu'dc sdi (2,23 mg catechin/ml nu'dc V6i ham nu'dc soi va 2,67 mg catechin/ml theo each dun sdi). Ham lu'gng polyphenol trong nu'dc tra nu Vdi khdng thay doi qua 1, 2 va 3 ngay bao quan lanh. Vd cam quan, ty le chip nhan nudc tra nu Vdi dang hat nhd va vda v§ mau sac, mui, vi chidm cao han so vdi dang hat to (tren 80%); each ham nu'dc sdi se giup tra nu Vdi cd mau sac, mui vi d§ duac nhilu ddi tuang chip nhan hon so vdi each dun sdi.
Do vay, de ed du'gc nhieu ham luang polyphenol, khuyin khich dung nu Voi dang hat nhd va nen c h i biln du'di dang dun soi.
Tir khoa: fra nu V6i, ham luvng polyphenol
I. DAT VAN DE
Cac nha nghien ciiu va san xuat tren t h e gidi da nghien ciiu va tao r a cac san p h a m cd k h a n a n g phdng chdng dudng huyet dudi nhieu h i n h thai khac n h a u . Tai N h a t Ban, nudc t r a la Oi —nudc dung ban che tang dudng huyet s a u a n - l a mgt hinh thai dudi dang nudc triet tach tii la di, sau do qua pha che de ddng chai, va da dugc sii d u n g phd bien tai nudc N h a t [1, 2]. Tra mudp dang dudi dang ddng gdi, sii dung bdng each nhiing gdi t r a vao nudc sdi, udng h a n g ngay, danh cho benh n h a n dai thao dudng, cung dugc sii dung phd bien tai mgt
s d n u d c chau A).
Cac n g h i e n ciiu ve t h a n h p h a n b o a t tinh sinh hgc ciia cac loai thuc vat da cho thay, h a m lugng polyphenol cd mdi tuong quan vdi cac h o a t tinh sinh hpc n h u iic che men tieu dudng (nhu alpha-glucose, a l p h a - a m y l a s e ) , chd'ng oxy hda [1,2]. Hon niia, cac nghien ciin ve nguyen lieu dang hat, la cho t h a y nguyen lieu khi dugc xay nhd min thi khi pha che se cd h a m lugng polyphenol cao hon hon do t a n g dien tich tiep xiic ciia nguyen lieu vdi dung mdi chiet tach dung trong p h a che [3).
Cay Vdi cd ten khoa hpc la Cleistoca- Tac gia: Truong Tuyet Mai
Dia chi: Vien Dmh dudng, 48 B Tang Bat Hd Dien thoai: 094 9911 777; 04-39716058 Email:[email protected]
48 Tap chi Y hpc du phdng, Tap XX, sd 2 (110)
lyx pperculatus (Roxb.) Merr a n d P e r r y thudc hg Sim (Myrtaceae) la loai cay trdng r a t quen thudc ciia n h a n dan t a [4]. Tii lau ddi, la va nu Vdi dugc diing de li hoac n a u lay nudc ud'ng gid'ng n h u la che x a n h hay nu hoa hde. Mgt cugc sang lgc tren 28 loai thuc v a t a n dugc d Viet Nam da tim tha'y nu Vd'i cd h a m lirgng polyphenol cao (tuong duong 128 mg catechin/gram trgng lugng khd) [5]. S a u dd, Nu Vdi t r i e t t a c h b d n g nudc da dugc thii nghiem ve hoat dgng iic che m e n tieu hda dudng tren dng nghiem va d a n h gia hieu qua giam dudng huye't tren dpng vat (chudt n h a t va chugt Wistar dai thao dudng) [6]. Ben canh do, cac thii nghiem tren dng nghiem va t r e n dgng v a t cho tha'y n u Vdi cd boat t i n h chd'ng t a n g dudng huye't s a u an, cho'ng oxyt hda va giam cholesterol m a u [7]. Ngoai ra, nu Vd'i la mpt nguyen lieu diing de udng tii r a t lau ddi, va dugc coi la a n toan khi sii dung.
Cho den nay, each pha che t r a nu Vdi thdng thudng ciia ngudi dan Viet N a m la h a m n u Vdi nguyen h a t vdi nudc sdi va ud'ng d a n trong ngay. Tren thuc te, n h a m t a n g cao tac dung sinh hda va tang tinh t h u a n tien khi sii dung, can cd nghien ciiu thii nghiem ve cam quan, chat lugng ciia t r a N u Vd'i dudi nhieu dang che bien va pha che khac n h a u . Muc dich ciia nghien ciiu nay la d a n h gia hinh thiic, chat lutong va cam quan ciia t r a nu Vdi s a u ddng gdi dudi 3 hinh t h a i khac n h a u vdi 2 each p h a che de tim r a kieu m a u thich hgp n h a t ciia t r a n u Vdi n h a m phuc vu cho nghien ciiu ve k h a n a n g giam dudng huyet ciia nu Vol t r e n benh n h a n dai thao dudng m a chung tdi se tieh h a n h trong thdi gian tdi.
II. PHUONG PHAP NGHIEN ClTU
2.1. Nguyen lieu
Nu Vdi khd m u a t a i cac chg t a i H a Ngi. Sau khi t h u mua, sang say lam sach va ddng gdi bao quan ndi khd rao cho de'n khi dua vao xay. Tieu chuan chgn nu Vd'i:
Nu Vdi trdn h a t , may, cd miii thom, khdng mdc, mau den xam cd do bdng mdi. Nu Vdi dugc dat m u a tii Hai H a u - N a m Dinh.
2. 2. Phu-ong p h a p tien h a n h 2.2.1. Sdn xudt trd nu Voi
N u Vdi khd s a u khi dugc chgn lua, s a n g say, cho say khd t a i n h i e t do 90°C trong 30 phiit. Tie'n h a n h thii nghiem xay theo 3 hinh t h a i va kich cd. Sii d u n g m a y cdt nghien, dieu chinh do md ciia 2 ludi dao de xay t h a n h 3 h i n h t h a i : d a n g nhd h a t (kich thudc <0,1 mm); dang viia h a t (kich thudc k h o a n g 0,2-0,6 mm); d a n g to h a t (kich thudc > 0.7 mm). Thuc hien tai cdng ty che Kim Anh, H a Ndi.
Sau khi xay t h a n h 3 dang h i n h thai, tie'n h a n h ddng gdi nhd. Ddng dang tiii lgc, mdi tlii chiia 2 g n u Vd'i xay. Tie'n h a n h ddng hop vdi so' lifpng 25 gdi/hdp. Cac hop thiet ke sa bg ve n h a n mac, dua cac thdng tin ve san pham: ten san pham, cdng dung, lieu lugng, each diing, bao quan, noi s a n xuat, ngay t h a n g san xua't va h a n sii dung.
2.2.2. Che Men nu&c trd nu Voi
Cac hop t r a n u Vdi s a u ddng gdi dugc van chuyen ve Vien Dinh dudng. Tien h a n h che bien 3 dang tra nu Vdi theo 2 each che bien: h a m nudc sdi va dun sdi.
Chuan bi nudc t r a nu Vdi cho xac dinh h a m lugng polyphenol:
P h a che' nudc t r a nu Vd'i tii 3 d a n g hinh thai theo thdi gian: h a m nudc sdi hoac dun sdi trong 3 phiit, 5 phiit, 10 va 30 phiit.
Thu lay nudc t r a n u Vdi va ghi ky hieu cho tiing loai, sau dd xac dinh h a m luong polyphenol cd trong nudc t r a n u Vd'i.
Che bien nudc t r a n u Vd'i cho thii Tap chi Y hoc du phdng. Tap XX, sd 2 (110)
nghiem cam q u a n :
D u a vao ke't q u a ve h a m lugng polyphenol t r o n g nudc t r a n u Vdi theo 3 dang va 2 each p h a che'va tdng sd thdi gian pha che. Tien h a n h pha che' nudc t r a nu Vdi cho thii nghiem cam q u a n bang each n h u sau: Mdi h i n h thai, chgn ngau nhien 60 gdi t r a n u Vdi xay, 30 gdi p h a che kieu h a m nudc sdi trong 30 phiit, vdi ty le 1 gdi/200 m L va 30 gdi p h a che b a n g each cho vao nudc dun sdi trong 10 phiit, ciing vdi ty le 1 gdi/200 mL. Sau khi h a m va dun sdi, t h u dugc nudc t r a nu Vdi, chuyen sang cac binh chiia nudc de tien h a n h cam quan. Cac binh nudc t r a n u Vdi dugc danh sd'ky hieu theo cac d a n g h i n h t h a i va each p h a che.
2.2.3. Xdc dinh hdm liegmg Polyphenol Sau khi p h a che se t h u dugc ta't ca cac m a u nudc t r a n u Vdi vdi cac kieu dang xay va each pha che khac nhau. Cac mau t r a se dugc de trong chai/lg kin cd dan nhan, sd hieu, dung de xac dinh ndng dd Polyphenol.
Ngoai r a mgt sd' m a u se dugc bao q u a n trong t u lanh (nhiet do tii 2-8°C) trong thdi gian tii 1, 2, 3 ngay, sau dd kiem t r a s u t h a y ddi ndng do polyphenol. Phuong p h a p xac dinh ndng do Polyphenol theo phuong p h a p so m a u ciia F o l i n - Ciocalteau. Tinh toan h a m lugng polyphenol dua theo dudng chuan ciia catechin de t i n h lugng catechin (mg) trong 1 ml nudc nu Vdi hoac trong 100 mg nu Vdi khd. Sau dd so sanh h a m lugng polyphenol ciia cac m a u nudc nu Vd'i de d a n h gia chat lugng gdi n u Vol theo h i n h thai va each pha che' khac nhau.
2.2.4. Ddnh gid cdm quan
Tie'n h a n h d a n h gia cam quan nudc t r a nu Vdi s a u ddng gdi va pha che t r e n 60 do'i tugng. Doi t u g n g t h a m gia d a n h gia cam q u a n la can bd Vien Dinh dudng va mgt so ngudi d a n sdng tai Ha Ndi, cd do
tudi tii 24 den 60 tudi. Ddi t u g n g t h a m la la n h u n g ngudi khdng hiit thud'c, khong mac b e n h ve miii hgng.
D a n h gia cam q u a n d u a theo P h a n tich cam q u a n va cho diem t r o n g TCVN 3215 - 79. Cac dd'i tugng ghi lai n h a n xet cu t h e cho t u n g mSu thii ve m a u , miii, vi.
Cgng diem cho tiing m a u phieu cam quan, d a n h gia chung, tdng hgp k e t q u a cam q u a n d u a t r e n so' phie'u d a n h gia hgp le, theo diing yeu cau. Diem sd t r e n phie'u cam q u a n dugc n h a n vdi he so q u a n trgng: 0,8 cho tdng so diem ve m a u sac; 1,4 cho tdng sd' diem ve miii; 1,8 cho tdng so' diem ve vi;
4,0 cho tdng so' diem chung. i; ;, hi 2.2.5. Nhap vd xu ly so lieu
Cac so' lieu p h a n tich cam q u a n va h a m lugng polyphenol dugc l a m sach va n h a p sd lieu bang chuong t r i n h E P I - I N F O 6.0. Xii ly sd lieu b a n g p h a n m e m S P S S 12.0.
IV. K £ T Q U A V A B A N L U A N 4.1. Six k h a c n h a u ve h a m l u o n g polyphe- nol cua t r a nu Voi dirdi nhieu hinh thai va each p h a che
Bang 1 cho t h a y su khac n h a u ve h a m lugng polyphenol trong t r a n u Vdi theo h i n h t h a i va thdi gian h a m li. So s a n h ve giiia cac h i n h thai, s a u khi h a m 30 phiit, lugng polyphenol dugc triet tach r a nhieu n h a t d dang h i n h t h a i nhd (2,23 mg c a t e - chin/ml), gap gan 2 lan so vdi dang h a t viia (1,31 mg/ml), gap b a n 3 lan so vdi dang h a t to (0,67 mg/ml), va gap gan 20 lan so vdi nu Vd'i nguyen h a t (0,08 mg/mL). Khi so s a n h ve thdi gian h a m n, nhin chung h a m lugng polyphenol dugc triet tach r a n h i e u n h a t sau 30 phiit h a m li. Neu de nguyen h a t n u Vdi thi lugng polyphenol triet tach sau 30 phiit h a m li trong nudc sdi cao gap b a n 10 Ian so vdi sau 3 phiit, cao gap 4 lan so vdi
50 Tap chi Y hpc du phdng. Tap XX, sd 2 (110)
sau 5 phiit, va sau 10 phiit thi h a m lugng polyphenol cung gan bdng sau 30 phiit.
N h u n g ngugc lai ddi vdi dang nu Vdi xay h a t dang nhd, lugng polyphenol triet tach dugc r a t nhieu ngay tai thdi diem sau 3 phiit h a m nudc sdi, chi kem 1,4 lan so vdi sau 30 phiit (1,53 mg/mL so vdi 2,23 mg/ml) va sau 10 phiit thi h a m lugng
polyphenol da triet tach bdng vdi thdi diem sau 30 phiit. Ddi vdi dang h a t xay to va vita, h a m lugng polyphenol dat cao n h a t sau 30 phiit, cao gap 2 - 3 lan so vdi s a u 3 va 5 phiit, s a u 10 phiit thi h a u n h u lugng polyphenol da d a t gan bdng s a u 30 phiit h a m trong nudc soi.
Bang 1. Ham lu'O'ng Polyphenol (tu'O'ng du'O'ng vd'i mg Catechin/ml nu'd'c tra nu Vol) sau 3, 5, 10 va 30 phut ham nu'O'c sol
Dang hat Nu Vol Nguyen hat Dang hat to Dang hat vua Dang hat nho
Ham 3 phut 0,01 0,23 0,77 1,53
Ham 5 phut 0,03 0,30 0,92 1,89
Ham 10 phut 0,08 0,60 1,23 2,22
Ham 30 phut 0,12 0,67 1,31 2,23
*) M6i s6 thi hien gia tri trung binh cua n=5 Tuong tu, b a n g 2 cho tha'y su khac nhau ve h a m lugng polyhenol trong t r a nu Vdi theo hinh thai va thdi gian dun sdi. So sanh ve giiia cac hinh thai, sau khi dun sdi 30 phiit, lugng polyphenol dugc triet tach ra nhieu n h a t d dang h i n h thai nhd (2,69 mg catechin/ml), gap gan 1,3 lan so vdi dang h a t viia (1,96 mg/ml), gap hon 2 lan so vdi dang h a t to (1,21 mg/ml), va gap hon 7 lan so vdi n u Vd'i nguyen h a t (0,36 mg/mL). Khi so sanh ve thdi gian dun sdi.
nhin chung h a m lugng polyphenol dugc triet tach r a nhieu nha't sau 30 phiit d u n sdi so vdi dun sdi trong 3, 5 va 10 phiit.
Ciing gidng n h u each h a m nudc sdi, d a n g h a t nhd cd h a m lugng polyphenol triet tach nhieu nha't ngay tai 3 phiit d u n sdi (2,08 mg/mL), trong khi dd dang h a t to va nguyen h a t thi lugng polyphenol triet tach khdng dugc nhieu (0,67 va 0,14 mg/ml).
H a m lugng polyphenol tang dan theo thai gian dun sdi d ta't ca 4 dang (Bang 2).
Bang 2. Ham lu'O'ng Polyphenol (tu'O'ng du'O'ng vd'i mg Catechin/ml nu'O'c tra nu Vol) sau 3, 5, 10 va 30 phut dun sol
Dang hat Nu Vol Nguyen hat Dang hat to Dang hat vua Dang hat nho
Dun 3 phut 0,14 0,67 1,21 2,08
Dun 5 phut 0,16 0,70 1,42 2,34
Dun 10 phut 0,25 0,86 1,82 2,47
Du n 30 phut 0,36 1,21 1,96 2,69
*) Moi so ihe hien gia lri trung hinh ctia n=5
Trong nghien ciiu nay, danh gia chat lugng ciia 6 dang tra nu Vdi da cho thay t r a n u Vdi dang h a t nhd cd h a m lugng polyphenol cao nha't. Hon mia, each dun sdi trong 30 phiit da giiip t r a n u Vo'i dang h a t nhd triet tach dugc h a m lugng polyphenol tdi u u n h a t , nhieu hon so vdi each h a m nudc sdi.
H a m lugng polyphenol dugc triet tach phu thudc vao h i n h thai ciia nu Vdi, cang t a n g dien tich tiep xiic vdi dung mdi thi k h a n a n g triet tach cang cao. Ngoai ra la yeu td nhiet do, thai gian triet tach, loai dung mdi Cling se gdp p h a n a n h hudng den lugng polyphenol triet tach [8]. Trong nghien ciiu nay, yeu td thdi gian va yeu to h i n h t h a i san p h a m dugc lay lam yeu td cd ban de so sanh su khac n h a u ve h a m lugng polyphe- nol, trong dieu kien gid'ng n h a u la d u n g mdi - n u d c thdng thudng, la nhiet dd sdi khi dun sdi, nhiet dp ciia nudc sdi khi ham.
Trong nghien ciiu nay, h a m lugng polyphenol dugc triet tach trong n u Vd'i phu thudc vao lugng thdi gian tiep xiic vdi nudc. Sau 10 phiit h a m hoac dun sdi, h a m lugng polyphenol da tang rd ret, khac biet so vdi thdi diem sau 3 va 5 phiit. Tuy nhien, neu de den 30 phiit h a m hoac dun sdi thi h a m lugng polyphenol dudng n h u da t r i e t tach dugc hoan toan tii nu Vdi. Cac ket qua trong nghien ciiu nay ciing gidng n h u cac ket qua trong nghien ciiu cua Pinelo va cs [8J ve su khac n h a u h a m lugng polyphenol khi triet tach theo thdi gian tiep xuc vdi dung mdi. Khi xet ve yeu td Bang 3. Ham lu'gng polyphenol cua
hinh thai, trong nghien eun nay, dang hinh thai h a t nhd cd dien tich tiep xiic vdi du g mdi nhieu n h a t , n e n da cd h a m lupng polyphenol triet tach nhieu nhat. Dieu nay Cling da chiing m i n h trong nghien ciiu ciia Van der Sluis [9] ve k h a n a n g t r i e t tach polyphenol trong la cay. N h u vay, chiing tdi cd the t a m thdi d u a r a khuyen cao la su:
dung t r a n u Vdi dudi d a n g xay nhd, pha che h a m va dun sdi trong thdi gian tii 10 den 30 p h u t se cho h a m lugng polyphenol tdi uu nhat.
Trong p h a n d a n h gia cam quan, tien h a n h d a n h gia cam q u a n t r e n ca 3 d a n g hinh thai tra nu Vdi va dudi 2 each che bien va dun sdi. Tuy nhien, chiing toi chgn thdi gian che bien thich hgp va dam bao ve triet tach h a m lugng polyphenol nhieu nha't. Do dd, thdi gian d u n sdi la trong 10 phiit va thdi gian h a m nudc sdi la 30 phiit. Bang 3 cho tha'y ve h a m lugng polyphenol ciia 6 mau cam quan. Chiing tdi ciing t a m thdi dua ra con sd udc tinh khi mdt ngudi binh thudng udng 200 ml/1 lan hoac khoang 500 ml/ngay nu Vdi vdi h i n h thai va each che bien k h a c n h a u thi ciing da cho lupng polyphenol k h a c n h a u rd ret. Dang chii y, theo udc tinh t r u n g binh ciia tac gia Cai va cdng su [10] thi mdt ngay mdt ngudi nen tieu t h u k h o a n g 1 g polyphenol, chinh vi vay, neu chiing t a udng mdi ngay 500 ml nudc nu Vdi d a n g h a m (tuong duong vdi 6,25g nu Vdi khd xay nhd) se tieu t h u hdn 1 g polyphenol. , .j,., 6 m l u tra nu Vol tru'O'c khi cam quan
Dang hat
Nguyen hat Dang hat to Dang hat viia Dang hat nhd
Ham tror mg CAT/
ml 0,12 0,67 1,31 2,23
ig 30 phut mg CAT/
100 mg 0,60 3,37 6,57 11,2
Dun soi trong 10 phut mg
CAT/ml 0,25 0,86 1,82 2,47
mg CAT/
100 mg 1,23 3,81 7,11 12,37
Uong 200 ml (ham)
mg CAT/ml
16 134 262 446
Uong 500 ml (ham)
mg CAT/ml
40 335 655 1.115
mg CAT/ml: twang 6uvng vai mg catechin/ml nuvyc nu Vdi mg CAT/100 mg: twang dwang vai mg catechin/100 mg nu Voi ktio
52 Tap chi Y hpc du phdng. Tap XX, sd 2 (110)
4.2. Danh gia cam quan nu'd'c t r a nu Vol dud'i nhieu hinh thai va each pha che
Dua vao diem cdng chung cam quan ve m a u sac, mui, vi ddi vdi nudc t r a nu Vdi trong bang 4 cho tha'y, ty le chap n h a n dugc, ty le thich va ty le r a t thich ddi vdi nudc tra Nu Vdi d nhdm h a m nudc sdi cao hon nhdm dun sdi. Trong nhdm h a m nudc sdi, ty le r a t thich va thich t r a n u Vdi dudi dang nhd la cao nha't (20% va 45%), tiep theo la dang viia, tiep theo la dang to. Tuy
nhien, cd tdi 55% so' ddi tugng lai cho rdng t r a nu Vdi dang to va p h a che kieu h a m nudc soi la chap n h a n dugc, do dd sau khi cgng ddn ty le chap n h a n dugc cho de'n r a t thich chiem tdi 88%. Ngugc lai ddi vdi each dun sdi, h a u b e t cac ddi tugng cam q u a n deu chap n h a n va thich ciia nudc tra nu Vdi dudi dang h a t to (70%), trong khi dd ty le ddi t u g n g khdng thich dang nhd va d a n g viia lai r a t cao (42 va 45%).
Mu'c do
Bang 4. Danh gia ve chung ve mau, mill va vj cua nu'd'c tra nu Voi du'di 3 dang hinh thai va 2 each che bien
Dang nho Dang vOa Dang to Dang nho Dang vira Dang to -Ham (n) - Ham (n) -Ham (n) - D u n sol -Dun sol -Dun soi
(n) (n) (n) Rdt thfch (%)
Thich (%)
Chdp nhan dugc (%) Khong thich(%)
Khong thich chut nao(%) Cgng ddn ti> rdt thich - c h i p nhan dugc (%) Cgng ddn t i i khong thich -khdng thich chut nao(%)
20,0(12) 11,7(7) 11,7(7) 0,0(0) 0,0(0) 13,3(8) 45,1(27) 36,6(22) 21,6(13) 20,0(12) 25,0(15) 20,0(12) 18,3(11) 36,7(22) 55,0(33) 38,3(23) 30,0(18) 36,7(22) 13,3(8) 11,7(7) 11,7(7) 40,0(24) 31,7(19) 18,3(11) 3,3(2) 3,3(2) 0,0(0) 1,7(1) 13,3(8) 11,7(7) 83,4 85,0 88,3 58,3 55,0 70,0
16,6 15,0 11,7 41,7 45,0 30,0
Trong bang 5, dua vao diem t r u n g binh cho thay miic do chap n h a n dang tra nu Vdi phu thupc vao diem sd, diem so cang cao thi miic do chap n h a n cang cao. Ddi vdi cam quan ve m a u sac, cac diem so t r u n g binh giiia 6 dang nudc t r a n u Vd'i khong t h a y ddi nhieu, su khac biet khdng cd y nghia thd'ng ke giua cac dang, giiia cac kieu pha che. Tuy nhien, cd the sdp xep thii t u ve kha nang chap n h a n m a u sac ddi vdi 6 dang n h u sau: dang t o - d u n sdi (2,09), dang t o - h a m (2,04), dang v i i a - d u n (2,03), dang v i i a - h a m (2,03), dang n h d - h a m (1,96), dang n h d - d u n (1,93). Ddi vdi cam quan ve
miii va vi, cac diem so' t r u n g binh giiia 6 dang nudc t r a nu Vdi da cd su khac biet cd y nghia thdng ke giiia cac dang, giiia cac kieu pha che. Diem so t r u n g binh ve miii va vi ciia d a n g n h d - h a m khac vdi d a n g v i i a - h a m va dang t o - h a m ; ddng thdi cung khac vdi dang n h d - d u n , cac su k h a c biet nay cd y nghia thd'ng ke vdi p < 0,05. Tuong t u ddi vdi d a n g v i i a - h a m , diem so' t r u n g binh ve miii va vi ciing khac vdi dang t o - h a m , k h a c vdi dang v i i a - d u n , ddng thdi ciing khac vdi dang n h d - d u n , cac su k h a c biet nay cd y nghia thdng ke vdi p<0,05. Cd the sdp xep thii t u ve k h a n a n g chap n h a n
Tap chi Y hpc du phong, Tap XX, sd 2 (110) 53
miii va vi ddi vdi 6 d a n g n h u sau: dang n h d - h a m , d a n g v i i a - h a m , dang t o - h a m , dang t o - d u n sdi, dang nhd-dun, dang vifa- dun.
Khi tdng cgng 3 diem ve mau sic, miii, vi, thii t u ve k h a n a n g chap n h a n chung ve nudc t r a n u Vdi n h u sau: dang n h d - h a m (10,6), dang v i i a - h a m (9,6), dang t o - h a m (9,3), dang t o - d u n soi (8,1), dang n h d - d u n
B a n g 5. O i e m trung binh ve m a u , diro'i 3 d a n g hinh thai
(7,0), d a n g v i i a - d u n (6,6) (bang 7). Bdhg phep n h a n he sd q u a n trgng ddi vdi die in tdng, cd su khac biet cd y nghia thd'ng ke ve diem tdng cgng giiia nudc t r a n u Vdi d a n g n h d - h a m vdi dang to va v i i a - h a m (22,1 ddi vdi 19,8 va 18,9). Trong khi dd, diem tdng ciia d a n g t o - d u n lai cd s u k h a c biet cd y nghia thd'ng ke so vdi d a n g v u a d u n va n h d - d u n (17,8 so vdi 14,7 va 14,6).
mui va vj cua nu'd'c tra nu V o l va 2 e a c h c h e bien
Dang hat nu Vol
Mau sac (n=60)
Mui (n=60)
Vj Diem cong (n=60) Diem cong (n=60) (sau nhan he so
quan trong)
Dang nhd-ham 1.96 ± 0,74a 4.36+1,86a, # 5.45 ± 2,90a, # 10.60 ± 4,76a, # 22.13 ± 7,93a, # Dangvua-ham 2.03 ± 0,82a 3.52 + 1,21b, # 4.32 ± 1,54b, # 9.67 ± 3,60a, # 19.80 ± 5,28b, # Dang to-ham 2.04 ± 0,66a 3.52 +1,47b 3.90 +1,19b 9.33 ± 2,90a 18.93 ± 4,90b Dang nhd-dun 1.93+0,75a 2.92 ± 0,91a 3.03 ± 0,83a 7.07 ± 1,72a 14.73 ± 3,33a Dang vda-dun 2.03 ± 0,93a 2.73 ± 0,95a 3.00 ± 0,90a 6.67 ± 2,01a 14.60 ± 4,10a Dang to-dun 2.09 ± 0,94a 3.31 ± 1,43b 3.54 ± 1,44b 8.13 ± 3,35b 17.80 ± 6,07b n=60; sir dung phwang phap test cap, p < 0,05 l<hi trong cot co ky hieu chw (a va b) khac nhau trong 2 nhom ham nwac soi va dun soi; ky hieu # (p<0,05) khi so sanh ciing dang nhwng khac nhom che bien.
Trong nghien ciiu nay, ket qua danh gia cam q u a n cho tha'y ddi vdi ca 3 d a n g h i n h thai thi each che bien h a m nudc sdi da cd ty le chap n h a n cao hon so vdi each dun sdi ddi vdi ca m a u sac, mui va vi. Trong 3 hinh thai, ve m a u sdc thi ty le thich m a u sdc ciia nu Vdi dang h a t to va viia chiem da sd, trong khi dd ve miii va vi thi da so' ddi tugng cam quan lai thich dang nu Vdi h a t nhd va h a t viia. Dua vao n h a n xet ve m a n sac, miii va vi trong phieu danh gia cam q u a n cho t h a y n h i n chung m a u sdc ciia nudc tra nu Vdi m a u n a u canh dan, mang mui, vi Vdi ro ret. Tuy nhien, mau sdc ciia nhdm nudc tra nu Voi d u n soi lai cd m a u n a u sam ban m a u ciia nhdm t r a nu Vdi h a m nudc sdi. Ve khoa hgc, cd the cho r i n g
h a m lugng polyphenol trong nudc n u Vdi p h a n a n h m a n sdc ciia nudc n u Vdi, m a u cang s a m thi lugng polyphenol ciing se nhieu hon, va dieu nay ciing da dugc chiing minh qua ket qua ve h a m lugng polyphenol giiia 2 nhdm dun sdi va h a m nudc sdi. Ve miii vi ciia t r a nu Vdi, da sd dd'i tugng cam q u a n cho rang, miii vi ciia t r a nu Vdi dang h a t nhd lai cd miii Vdi rd ret va cd vi dang nhieu hon so vdi cac dang viia va to. N u Vdi d a n g h a t nhd s a u khi udng de lai h a u vi nhieu hon so vdi 2 dang cdn lai. Tuy nhien, khi mdi ud'ng thi dang hat vifa lai cam t h a y de udng vi khdng cd nhieu vi ddng. Ve khoa hgc, h a m lugng polyphenol nhieu cung se gdp p h a n lam tang cam giac chat, dang, do dd dang h a t nhd vdi ham lugng polyphenol
54 Tap chi Y hpc du phdng. Tap XX, sd 2 (110)
triet tach nhieu se lam tang cam giac chat va dang ciia nu Vdi nhieu hon.
V. KET LUAN
H a m lugng polyphenol triet tach tii t r a nu Vdi dang nhd h a t dat cao nha't, va h a m lugng polyphenol theo each dun sdi cao hon so vdi cach h a m nudc sdi (2,23 mg catechin/ml nudc Vdi h a m nudc sdi va 2,67 mg catechin/ml theo each d u n sdi). H a m lugng polyphenol trong nudc t r a n u Vol khdng thay ddi qua 1, 2 va 3 ngay bao q u a n lanh. ;i-v-.:,a,r ,
Ve cam quan, ty le chap n h a n nudc t r a nu Vdi dang h a t nhd va viia ve m a u sac, miii, vi chiem cao b a n so vdi d a n g h a t to (tren 80%); each h a m nudc sdi se giiip t r a nu Vdi cd m a u sac, miii vi de dugc n h i e u ddi tugng chap n h a n hon so vdi each dun sdi.
TAI LIEU THAM KHAO
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Medicine Publisher Hanoi (in Vietnamese), 2001.
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Tap chi Y hpc du phdng, Tap XX, sd 2 (110) 55
QUALITY ASSESSMENT OF NU VOI TEA BY VARIOUS PROCESS ING METHODS
1 ruong Tuyet Mai, Truong Hoang Kien*, Nguyen Xuan Ninh ;.,, > y.
National Institute of Nutrition, Hanoi f^ ' • ^ . * ;V iVii
* Quangninh Food Administration . w nBrl Mu Vol was produced by 3 different
styles, was packaged 2 g of Voi'set. Voi tea was maked by the boilling or the stewing in hot water in different time, 10 min, 20 min and 30 min. The collected Voi tea was determined polyphenol content and w a s tested the taste, smell, favour, colour. R e - sults, the polyphenol content was highest in the Voi tea which was boiled, was higher t h a n the Voi t e a which was stewed (2,23
mg catechin/ml Voi t e a with stewing and 2,67 mg catechin/ml Voi tea with boilling).
Voi tea t h a t were produced in small style and in medium style h a d the highest a c - ceptability on the color, smell, and t a s t e (>80%). The percentage of t h e accepbility was higher in the Voi t e a with stewing t h a n in the Voi t e a with boilling on the color, smell, and t a s t e .
Keywords: Voi tea, polyphenol content
i/\T
56 Tap chi Y hpc du phdng. Tap XX, sd 2 (110)
