KHOA HOC CONG NGHE
AI\IH HUOIXIG CIJA iVIQT S O Y E U T d DEIXI THOI GIAIXI LEIXI IVIEIXI, HAIVI LUOIXIG COiV V A C H A T LUOIXIG CAIVI PUAIXI C U A 5AIXI PHAIVI 5 U A K E F I R CHAIXIH LEO
Nguygn Thi Um Do^kn^ D$ng T h ^ Y^n lMi\ Nguyen Diic Doan^
TOMTAT
San ph^m sua len men Kefir la mot dang san pham yaourt co chiia nhieu he vi sinh vat giup h6 trgr tieu hoa va cai thien he thong mi^n djch. Nghifen ciru dupe hen hanh nham khao sat ty 16 dich chanh leo, gidng vi sinh vat Kefir va do axit dimg den thoi gian len men, ham luong con va chat luong cam quan cua san pham.
Ket qua chi ra sua chua Kefir bd sung chanh leo duQc san xuat bang each phdi trpn siia tuoi ti&t tning vdi 6%
dich chanh leo roi len men bang vi sinh vat trong Kefir voi ty le tiep gidng 10% den do axit 95T thi thdi gian len men 23 h dp con la 2,2 (%Y) va cho chat luong cam quan tdt. Ngoai ra, bang cac phuong phap danh gia cam quan da xac dinh dupe khi bd sung dich duong succrose o nong do 30% voi ty le 40% vao sua Kefir sau len men mang huong vi va trang thai hai hoa va duoc ua chu6ng.
Tii khda: Chanh leo, KeSr, sua chua.
I.DATVANDE
Kefir la mot san pham sua I6n men nho h& vi sinh vat phong phu bao gom nhom vi khuan lactic, nam men, va mot so nhom khac (Quach Diic Tinh va cs, 2013; Poga'cic et al, 2013), chiing duoc xem nhu mot san pham probiotic tu nhien (Nalbantoglu et al, 2014). Mot so nghien cuu da cho tiiay cac vi khuan probiotic trong Kefir rat co loi cho siic khoe (Zheng et al, 2013) co kha nang ti^u diet hay bat hoat cac vi sinh vat gay benh giiip h6 tra tifeu hoa, cai thien he thong mien dich (Edward, 2008). He vi sinh vat trong Kefir phat trien manh trong moi truong sUa, chiing su dung lactose va protein tao ra nhirng san pham ma con nguoi co the d& dang tieu hoa va su dung (Rizk et al, 2009). Do vay, siia len men Kefir la dang thuc pham khong chi mang gia tri dinh duong cao ma con lam giam cholesterol trong mau, guip giam stress va cang thing do co do ruou nhe (Harun, 2015; Semih
& Oz-em, 2003). Ngoai ra, he vi sinh vat frong Kefir san sinh ra axit lactic, chat khang sinh, bacteriocin se han che sir phat ti-ien cua cac vi sinh vat gay hong hoac gay benh ti-ong san pham siJa Kefir (Lui et al, 2002). Voi nhieu im diem va cong dung nhu vay, cac san pham siia Kefir txi lau da dupe sii dung rat rong rat a nhieu nuoc tren the gioi.
' Khoa Cdng nghe thuc pham, Hoc vien Nong nghiep Viel Nam
Email; [email protected]
Dong sua chua Kefir c6 bd sung hoa qua vira co huong thom vira giiip tieu hoa tdt dugc moi ngudi ua thich. Hien nay o Viet Nam dong san pham siia Kefir nay tren thi trucmg ciing nhu cac nghien cmi v^
chung con rat han che, co mot sd it nghien cuu ve dong san pham nay nhu Kefir bo sung dau tay ho§c sira dau nanh Kefir (Nguyin Thi Lam Doan va Tran till Bich Phugng, 2008; Tran Thi Ha Ny, 2015).
Chanh leo rat phd bien 6 Viet Nam, dtroe biet d^n vdi mau vang tu nhien hap dan, huong vi dgc dao bao gom chu yeu la este, aldehyt, rugu va xeton va co mot lugng lon vitamin A va C, kah, chat xo, carotenoid, polyphenol... (Werkhoff et al., 1998;
Nguyen Phuoc Minh, 2014).
Do do, nghien cuu nay khao sat anh huong cua mot sd yeu td den thoi gian len men, do cdn va chat lugng cam quan cua san pham siia chua Kefir co bd sung chanh leo d^ dua ra cac thong sd phu hgp cho loai san pham nay.
2. VAT UEU VA PHUDNG PHAP NGHIBV CUU 21.V4tli§u
Siia: sua tuoi tiet triing khong duong ciia Vinamilk dupe mua tai sieu thi BigC; nam Kefir tiroi dupe mua a gia dinh a viing A'li, phia Tay Tay Tang, Trung Qudc. Chanh leo duge mua tai sieu thi BigC, lua chpn trai chanh day co kich thuoe ddng d^u, con tuoi va CO mau tim.
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1+2 - THANG 2/2019
KHOA HOC CONG NGHE
2.2. Phuong phdp nghi6n cuu 2.2.L Chuan bi gidng vi sinh vatKetir Theo mpt sd nghien cthi da chi ra de chuan bi gidng vi sinh vat Kefir cho len men dugc tien hanh nhu sau: hat Kefir dugc bd sung vao stia tuoi thong thudng voi ty le 5 ddn 10% sau do len men a nhiet dp phong khoang 25"C h-ong 20 - 22 h khi pH dat 4,5 - 4,7 (Gnocu et al, 2017; de Silva, 2018). Tai pH nay vi khuan lactic v^ nam men co sd lupng lon va hoat tinh tdt dam bao cho qua trinh len men khi san xuat sira Kefir (de Silva, 2018). Trong nghien oiu nay gidng vi sinh vat Kefir dugc chuan bi voi ty le 7% theo khdi lirgng. Lay 93 gam siia ttroi ti$t tiling khdng duong cua Vinamilk cho vao binh tam giac 250 ml, sau do can 7 gam gidng Kefir cho vao binh tam giac tren, lac deu cho Kefir phan bd deu trong mdi truong de 6 nhiet do phong khoang 27 - Z(fC sau 14 h bat dSu theo doi su bien ddi do axit ciia moi tnrdng. Kdt thiic len men khi pH cua moi trudng dat 4,5 - 4,7. Tiep do, loc tach hat Kefir ra khoi dich, dting dich do cho thi nghiem tiep theo.
2.2.2. Chuan bi dich chanh leo
Chuan bi chanh leo: Diing dao bd va tach My phan rupt qua, sau dd diing thia danh tan phan nay, cong doan ti^p theo la Ipc de loai bd phan hat va thit qua. San pham thu diroc la dich qua. Dich qua cd do pH =2,8 va ham lugng chat kho hda tan ("Bx) la 15.
Dich qua dupe thanh tning 80 - 90''C trong 2 phiit (Le My Hong vacs, 2009).
2.2.3. Phuong phap bd tri thi nghiem Khao sat anh hudng cua chanh leo ddn thdi gian Idn men, do cdn va chat lugng cam quan cua san pham
Siia tuoi tiet trimg khong dudng cua Vinamilk dugc phdi ch^ voi dich chanh leo theo cac ty le 0,4, 6 va 8% theo the tich, cay gidng Kefir 10% da chuan bi 6 muc 2.2.1 (Ergoniil, 2007). Sau do len men a nhiet do 28 - 30^C dimg len men khi dp chua dat 9 5 ^ (Quach Due Tinh va cs, 2013). Tiep do tien hanh phdi che dich dirdng succrose a nong dp 30% vdi ty 16 phdi chd 30% (Nguyin Thi Lam Doan va TrSn Thi Bich Phugng, 2008). Rot hop va bao quan d- nhiet dp 4 - e^'C.
Khao sat anh hudng cua ty le men gidng ddn thdi gian len men, do cdn va chat lugng cam quan cua san pham
Theo nghien cuu truoc cua Ergoniil, 2007 khi nghien ciiu san xuat Kefir co bo sung dau tay da tim ra ty le tiep gidng la 5% va nghien ciiu cua Nguyin Thi Lam Doan va Tran thi Bich Phupng, 2008 cung nghien ciiu san xuat Kefir cd bd sung dau tay tim ra ty le tidp gidng la 7%. Trong nghien ciiu nay ty le tiep gidng Kefir 5,10,15% da dirge sii dung.
Cac buoe tien hanh cung tiiong tu nhu thi nghi&m khao sat anh huong cua chanh leo va co ke thtra k^t qua nghien cihi ciia thi nghiem trudc ve ty 16 chanh leo va kdt hpp vdi ty le gidng Kefir la 5,10,15%.
Khao sat do axit ddng ket thuc len men den thdi gian len men, do cdn va chat lugng cam quan cua san pham
Tien hanh khao sat voi 04 dp axit dimg 90T, 95T, 100°T, 105'T (Nguyin Thi Lam Doan va Tran Thi Bich Phuang, 2008).
Khao sat ty Id phdi tidn dich dudng succrose ddn chit lugng cam quan cua san pham
San pham dupe phdi chd dich duong succrose d' ndng dd 20, 30, 40% vdi ty le phdi trpn 20, 30, 40%
(Nguy&n Thi Lam Doan va Tran Thi Bich Phupng, 2008).
2.2.4. Cac phumig phap phan tich cac chi tieu theo ddi
Xac dinh do axit: dupe tien haiih theo phuong phap chuan dp vdi chat chi thi mau la phenolphtalein va duoc bieu thi bang do Thomer ("T) nhu mo ta ciia Lam Xuan Thanh, 2004.
Xac dinh do cdn bang phuong phap tien hanh theo nhu mo ta ciia Bin Thi Nhu Thuan va cs, 1992 va dugc bieu thi bang % (V).
Danh gia cam quan theo TCVN 3216-94, cac chuydn gia danh gia cac chi hfeu tren mpt thang diem cd cau tnic ttr 0 "san pham hdng" den 5 "san pham tdt". Diem cua chi ti6u 5 neu nhu trong chi tieu dang xet san pham c6 tinh tdt dac tnmg va ro ret cho chi tifeu dd va diem 0 ndu san pham dugc coi la hong va khong su dung dugc.
2.2.5 Xuly so Udu
Sd lieu thi nghidm dupe phan tich trfen phan mem Microsoft Excel va Minatab 16.
3.KETQUAVATHADLUAN
3.1. Anh huong ciia ty 16 chanh leo ddn thdi gian I6n men, dO c6n v^ chat lugng cam quan cua san phIm
KHOA HOC CONG NGHl Ket qua da chi ra cd su khac biet ve thdi gian len
men giua c6ng thuc bo sung chanh leo va cdng thiic khong bd sung dich chanh leo. Cu the, a c6ng thiic khong bd sung dich chanh leo thdi gian len men de dat dp asdt 95°T keo dai tm 26 h, ti-ong khi dd khi bd sung 8% dich chanh leo thi thdi gian len men nit ngdn chi cdn 22 h. Tai cac cong thiic bd sung 4 va 6%
dich chanh leo thi thdi gian len men keo dai lan luat la 23,5 va 22,5 h. Do ban chat cua dich chanh leo mang moi truong axit cd pH thap (Le My Hdng va cs, 2009), khi bd sung vao dich sua se lam pH cua dich sira giam, bd sung cang nhieu chanh leo thi thdi gian I6n men se dupe nit ngan.
Dp cdn giiia cac cdng thuc bo sung dich chanh leo o cac ty le khac nhau ciing ed su khac nhau, bd sung 8% dich chanh leo cho san pham co dp cdn cao nhat dat 2,5%; d6 cdn sinh ra thap nhat d' cdng thiic khdng dupe bd sung dich chanh leo (0,9%). Theo nghien ciiu cua Kwak et al, 1996 da quan sat su giam ham lupng dudng lactose va gia tri pH trong sudt qua trinh len men lactic. Ngoai ra nam men cung su dung dudng lactose va cac dudng khac d^ san sinh ra cdn nhd qua trinh len men rugu. Bd sung chanh leo cung ddng nghia voi viec bd sung them ngudn dinh duong cho nam men sinh trudnig, phat trien va sinh cdn chinh vi vay do cdn se dat cao hon 6 cac cong thiic cd bd stmg them dich chanh leo. Theo mpt sd nghien ciiu trudc da cho tiiay phu thuoc vao qua trinh len men, nhiet dp va thdi gian len men va thanh phan mdi truong su dung ma ham lugng cdn ti-ong san pham Kefir dao d6ng tir 0,06% den tdi da la 3%
(Korole, 1988; Guzel - Seydim et al, 2000).
Bang 1. Anh hudrng ciia ty 1$ chanh leo tdi thdi gian I6n men va dp cdn cua san phdm Ty le chanh leo
phdi che (% theo the tich)
0 4 6 8
Thai gian len men (h)
26 23,5 22,5 22
Do con (%V) eg"! ± 0,005 1,8' ± 0,07 2,1' ± 0,05 2,5" + 0,03 Ghi chu: cac sd trong cung mot cdt cd mang chtr cai khac nhau thi khac nhau cd y nghia & miic y nghia a = 5%.
De lua chon dugc ti le phdi che dich chanh leo thich hgp, ngoai cac chi tieu tr6n thi chat lupng cam quan cua san pham cung la mot yeu td quyet dinh, lua chpn dugc ty 16 bo sung thich hgp se cho san
pham sau khi len men cd mui vi hai hoa huong thom hap dan. Tuy nhi6n, neu ty le phdi che qua cao thi hirong vi chanh leo se at di huong thom dac trung ciia sira Kefir, con ndu ty le phdi chd qua thap se khong tao ra dugc huong vi chanh leo dac tnmg.
Ket qua danh gia cam quan a bang 2 cho thay ty le chanh leo bo sung cd anh hudng ro ret tdi cac chi tieu mau, miii, vi cua san pham. Cac chi tieu cam quan ve mau, miii, vi giua cong thiic khdng va cong thiie cd bd sung chanh leo deu cd su khac bi6t cd y nghia d miic a = 5%, duy chi cd tinh chat cam quan ve trang thai la khac nhau khong cd y nghia d tat ca cac cong thuc. San pham cho diem sd cam quan cao nhat do la san pham dirge bd sung 6% dich chanh leo vdi 4,6/5 diem 6 tat ca cac chi tieu san pham duoc danh gia la cd miii thom dac trung cua chanh leo quyen vdi miii sira chua va mtii rugu ethanol, vi chua diu ngpt ndng nhe cua cdn, san pham kha ddng nhat va cd mau vang nhat dac tnmg cua chanh leo.
Bang 2. K^t qud ddnh gid cam quan miu, miii, vi, trang thdi ciia sdn phfci a cdc cdng tinic c6 ty 16 b6
sung lugng dich chanh leo khde nhau Ty le chanh leo
phoi che {% theo the tich)
0 4 6 8
Mau 2,8' 3,8"
4,6"
3,6' Mui 3,0»
3,6"
4,6"
4,0"
Vi 3,6' 4,2"
4,6"
4,8' Trang
thai 4,4"
4,6"
4,6' 4,6- Ghi chii: cac sd trong ciing mdt cdt cd mang cha cai khac nhau thi khac nhau cd y nghia d miic y nghia a = 5%.
Tir 2 bang tr6n cho thay cong thuc bo sung 6%
dich chanh leo cd thoi gian I6n men 22,5 h, ham lugng cdn sinh ra dat 2,1% phii hop voi cac san pham sua Kefir noi chung (Guzel - Seydim et al, 2000) voi chat lupng cam quan dugc danh gia vdi sd diem cao nhat Vi vay, eong thire bo sung 6% dich chanh leo se la ty 16 dupe lua chpn cho cae thi nghiem tidp theo.
3.2. Anh huong ciia ty 1$ men giong Kefir d^n thdi gian I6n men, dO cdn vd chdt lupng cam quan cua san pham
Qua trinh l6n men dupe bat dau khi siia duoc b6 sung dich men gidng Kefir, men cd anh htrdng toi thdi gian I6n men va chat lugng san pham. Neu bo sung vdi mpt luong lon men gidng thi thdi gian len men ngan, vi khuan sinh huong chua du thdi gian de NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1+2 - THANG 2/2019
KHOA HOC CdNG NGHE
t h u c h i d n v a i t r d c u a m i n h . N e u b d s u n g m e n g i o n g vdi ty 16 q u a t h a p thi q u a t r i n h len m e n lactic y e u , t a o CO h d i c h o vi k h u a n t a p n h i 6 m p h a t t r i e n g a y miii la, d d n g t h d i t h d i g i a n len m e n k e o d a i k h o n g m a n g lai hieu q u a k i n h t e ( N g u y S n T h i L a m D o a n v a T r a n t h i Bich P h u a n g , 2 0 0 8 ) .
Cd t h d n h a n t h a y r a n g ty 16 b d s u n g m e n g i d n g c a n g n h i e u tiii t h d i g i a n I6n m e n c a n g d u g c n i t n g a n va h a m l u g n g c d n s i n h r a c a n g n h i e u . K h i sir d u n g 5%
m e n g i d n g t h a i g i a n I6n m e n k e o dai 24,5 h v a dp c d n chi d a t 1,4% t r o n g k h i b d s u n g 15% m e n g i d n g t h d i gian len m e n d u o c n i t n g d n x u d n g c o n 22 h va dp cdn sinh r a d a t 2,7%. T h e o m p t sd n g h i e n ciiu d a c h i r a n ^ m e n la t h a n h p h a n c h i n h d e t a o e t h a n o l n h u n g n h d m vi k h u a n lactic t r o n g Kefir d a c b i e t la cac loai t h u o c c h i L a c t o b a c i l l u s l e n m e n di h i n h c u n g cd k h a n a n g s a n s i n h e t h a n o l I6n tdi 0,25% v a CO2 (Marshall, 1984). T h e o n g h i e n ciiu c u a G u z e l - S e y d i m v a c s , 2000 e t h a n o l d u g c s a n s i n h t r o n g s u d t q u a tiinh len m e n Kefir n h u n g tir 0 d e n 10 h t a n g r a t it k h o n g d a n g k e va c h i t a n g m a n h tir 15 d e n 22 h len m e n .
B a n g 3. A n h h u o n g c u a t y 1§ m e n g i d n g d^n thdi gian Idn m e n vd do c o n ciJa san p h a m T y 1& m e n g i o n g
b o s u n g (% t h e o t h e tich)
5 10 15
T h o i g i a n l e n m e n (h)
24,5 23 22
D p c o n («V)
1,4= ± 0,03 2 , 0 ' ± 0 , 0 5 2 , 7 ' + 0 , 0 2 Ghi chu: cac sd trong cung mdt cdt cd mang chii cai khac nhau thi khac nhau cd y nghia d miic y nghia a - 5%.
Kdt q u a d a n h g i a c a m q u a n c h o t h a y , s a n p h a m a tat ca c a c c o n g t h i i c d e u d u g c d a n h gid k h a tdt, cd miii sira c h u a k e t h o p v d i m u i t h o a n g c u a c h a n h leo, vi c h u a n g p t h a i h o d q u y e n gitra siia v a vi t r a i cay, san p h a m t u o n g ddi d o n g n h a t . D u y c h i cd c o n g t h u c sii d u n g ty 16 m e n g i d n g b d s u n g la 5% tiii c h o c a m q u a n v e m a u c h u a dtroe d a c t n m g c h o san p h a m , m a u v d n g c u a c h a n h leo c d n n h a t , k d t q u a xir li t h d n g k 6 c u n g e h o t h a y s u k h a c b i e t la c o y n g h i a d' m i i c a = 5% v e c a m q u a n m d u s a c giira c o n g t h i i c s u d u n g 5%
m e n g i d n g vdi h a i c d n g t h i i c c d n lai.
6 c o n g t h i i c b d s u n g 10% l u p n g m e n g i d n g thi d i e m c a m q u a n d u p e d a n h gid v e m a u , miii va vi dat c a o n h a t Ian l u p t la 4,6, 4,8 vd 4,8. T y le 10% ndy s e
d u o e l u a c h o n s u d u n g c h o c a c thi n g h i e m tidp t h e o vi c d t h d i g i a n l6n m e n vira p h a i 2 3 h v a h d m ltrpng c o n d a t 2,0% phii h g p s a n p h a m Kefir (Guzel - S e y d i m e t a l , 2000).
B a n g 4. K^t q u a ddnh gid c a m quan m a u , miii, vi, trang thai ciia s a n p h a m a cdc c d n g thiic cd t y 16 m e n
g i d n g k h a c nhau T y le m e n g i o n g
b o s u n g (% t h e o t h e tich)
5 10 15
Mau 4 , 0 ' 4,6"
4 , 4 "
Mill
4 , 6 ' 4 , 8 ' 4 4al>
Vi 4 , 4 "
4 , 8 ' 4,6"
T r a n g t h a i 44^' 4,6"
4,8"
Ghi chu: Cac sd trong cung mdt cdt cd mang chU cai khac nhau thi khac nhau co y nghia d muc y nghia a = 5%.
3.3. D o axit d u n g a n h h u o n g d^n thoi gian I6n m e n , d 6 cdn vd c h a t l u g n g c a m quan ciia san p h ^
D p axit m a tai d d q u a t r i n h I6n m e n k e t thiic c u n g la m o t y e u td c a n q u a n t a m t r o n g v i e c san x u a t sira Kefir vi n d q u y e t d i n h d e n c h a t lirong s a n p h a m Cling n h u tinh k i n h t e c h o n h d s a n x u a t , v d i b d n c o n g thiic k e t thiic q u a t r i n h len m e n d 4 d o axit k h a c n h a u : 90, 9 5 , 100 vd 1 0 5 T , l u o n g d i c h c h a n h leo b d s u n g vdo Id 6% v a t y 16 m e n g i o n g sir d u n g la 10%. K e t q u a t h u d u g c c h o t h a y d e d a t d u p e d p axit d i m g c d n g Idn thi t h d i g i a n l6n m e n c a n g d a i v a l u o n g e d n t a o r a c a n g Idn. C a c h k h o a n g 2 h thi dp axit t a n g len 5°T.
T u y n h i e n k h i d a t d p axit c a o t d c d p t a n g axit c h a m d a n vd thdi g i a n k e o dai h o n . T h e o n g h i e n c u u ciia Leite e t al, 2013 t r o n g s u d t q u d t r i n h len m e n axit t a n g n h a n h Id k d t q u a ciia v i e e h i n h t h a n h m p t sd axit hiiu c a n h u axit lactic, axit a c e t i c . Khi d p axit t a n g c a o 1dm p H ciia m o i t r u d n g g i a m x u d n g lic c h e s u h o a t d o n g c u a vi k h u a n l a m c h o q u a t r i n h s i n h axit c h a m d a n c h i n h liic n a y lai la t h d i k y h o a t d o n g m a n h m e c u a n a m m e n n e n l u p n g c d n s m h r a t a n g m a n h ( N g u y d n T h i L a m D o a n vd T r d n thi B i c h P h u g n g , 2008).
B a n g 5. Mdi quan h $ giiia do axit d i m g voi thdi gian Ifen m e n vd h d m l u g n g c o n D o axit d i m g
ro
90 95 100 105
T h o i g i a n len m e n (h)
21,0 23,0 25,5 29,0
D o c i n (%V) l,8'i ± 0,02 2 , 2 ' ± 0 , 0 6 2 , 4 ' + 0,08 2 , 5 " ± 0 , 0 5
KHOA HQC CONG NGH|
Ket qud ddnh gid cam quan d' hat cong thtic cd dp axit dimg a 95 vd 100<T su khde biet Id khong ed y nghia a miie a = 5% vd tat cd cac tinh chat cam quan, trong dd, d' dp axit ket thiie len men la 9 5 T thi diem sd cam quan eho tat cd ede tinh chat ddu dat diem cao nhat. Cdn lai, hai cong thiic cd dp axit k6t thiic len men d* muc 90 va 105T cho diem sd cdm quan v6 cac tinh chat mdu, miii, vi va trang thai deu thap hon.
Khi san pham cd dp axit dimg 95 vd lOOT dupe danh gid la cd miii thom cua siia chua vd chanh leo tuy nhi6n sdn pham dp dimg lOOT cd vi hoi chua gat.
Nhu vay dp axit ket thiie I6n men 9 5 T la gid tri thich hgp dd tao san pham stra Kefir chanh leo.
Bang 6. K^t qua ddnh gid cdm quan v^ mdu, miu, vi va trgng thai cua san pham 6 cac cdng thiic c6 do axit
dimg khac nhau Do axit ro
ket thiic len men
90 95 100 105
Mau 4,0' 4,6' 4,2"
3,6' Mui 3,6*
4,8' 4,6' 4,0'
Vi 3,8' 5,0"
4,6' 4,0'
Trang thai 4 4ab 4,8' 4,6' 4 4ab Ghi chii: Cac sd tiong cung mdt cdt cd mang chir cai khac nhau tbi khac nhau cd y nghia d muc y nghia a =5%.
3.4. T y 16 p h d i c h d d i c h d u d n g s u c c r o s e a c d c n d n g d p k h d e n h a u a n h h u o n g d ^ n c h ^ t l u g n g c a m q u a n c u a s a n p h I m
B a n g 7. K ^ t q u a d d n h gid c a m q u a n v ^ m d u , m u i , vi v d t r a n g t h d i c u a s d n p h a m o c d c c 6 n g t h i i c c d t y 1^
p h d i c h ^ d i c h dudmg s u c c r o s e o c a c n o n g d p k h a c n h a u
N 6 n g dp d u o n g , ty 16 p h o i c h e 20% s u c c r o s e , 20%
20% s u c c r o s e , 30%
20% s u c c r o s e , 40%
30% s u c c r o s e , 20%
30% s u c c r o s e , 30%
30% s u c c r o s e , 40%
40% s u c c r o s e , 20%
40% s u c c r o s e , 30%
40% s u c c r o s e , 40%
Mau 4,0' 4 , 4 "
4,6' 4,6' 4 , 4 "
4,6' 4 , 2 "
4 4^1) 4,4"'
Min 4 , 4 ' 4 , 4 "
4,6"
4,2"' 4 4^1'
4,8"
4,6' 4,0' 4 , 2 "
Vi 4,0' 4 , 4 "
441^
4,4"' 4,6"
5,0' 4,0' 4,0' 4,0'
Trang thai 4,6"
4,6"
4,8"
4,4"' 4,6' 4,8' 44a' 4,6"
4,6' Ghi chu: Cac sd trong cimg mdt cdt cd mang chu cai khac nhau thi khac nhau co y nghia d mdc y nghia a =5%.
San pham Kefir de tao miu vi va trang thdi thich hgp can cd them cong doan phdi che vdi dich dirdng succrose sau qud trinh len men ket thiie vi khi do axit cao luc ben gel cua sdn pham gidm, rat d6 lam san pham bi phan lop (Nguy6n Thi Lam Dodn va Trdn Thi Bich Phugng, 2008). Chinh vi vay, de hoan thien cae thong sd thich hpp cho san pham siia Kefir chanh leo cho chat lupng tdt, ty le phdi che dich dudng d cac ndng dp khde rihau dugc xac dinh. Thi nghiem tien hdnh phdi che dudng succrose d ndng dp 20, 30, 40% vai ty le 20, 30, 40% vao dich Kefir sau len men. Ddnh gia cam quan sdn pham d cdc cong thiic phdi che khac nhau cho thay trong eac tinh ch^t cam quan thi tinh chat vi d cdc cong tiiiic cd su khac nhau nhidu hon so voi cac tinh chat khde ve mau, mtii va trang thdi (Bang 7).
6 cong thiic phdi trpn succrose d ndng dp 30%
vdi ly 16 khdi che 40% eho diem sd cam quan cao nhat, dae biet tinh chat cam quan ve vi dat 5,0/5,0 diem, nhu vay ty le phdi tron ndy dupe chpn de tao san pham. Ty le phdi che succrose trong kdt qua nghien ciiu ciia Nguydn Thi Lam Dodn va Tran Thi Bich Phugng 2008 khi nghien ciiu sdn xuat siia Kefir cd bd sung ddu tay tun ra ndng do succrose 30% ty 16 phdi che 30%. Dieu nay ed the ly giai do dfi pH ciia dich chanh leo (2,8) thap hon so vdi do pH cua dich ddu tay (4,2) chinh vi vay de tao ra chat lupng tdt can tang ty le bd sung.
4. KET LUAN
Trong qud trinh tao san pham sua Kefir ty le bo sung dich chanh leo, gidng vi sinh vat Kefir da anh huong Idn den thoi gian len men va ham lupng con va chat lupng earn quan cua sdn pham. Ket qud tiii nghiem cho thdy nen bd sung ty 16 chanh leo Id 6% va khong n6n bd sung nhieu, ty le tiep gidng la 10%, dp axit dimg la 9 5 ^ thi thdi gian len men 23 h dp con la 2,2 (%V) va cho chat lupng cam quan tdt. Dich dudng succrose dupe bo sung vao giiip dieu hda chii yeu vi ciia san pham va lam tang dp sanh cua san pham, nghi6n ciiu da xac dinh khi bd sung dich dudng succrose nong dp 30% voi ty 16 40% vao sua Kefir sau len men mang huong vi va trang thdi hdi hda.
5. KIEN NGHI
Tir cdc ket qua da thu dupe, de hodn thien va c6 the dira quy trinh san xudt san pham tren quy mo lon cdn nghi6n ciiu ddnh gia cdc gid tri dinh duong va tac dong cd loi cua san pham den siic khde.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1+2 - THANG 2/2019
KHOA HOC CONG N6HE
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Chemistry, 46:1076 -1093.
FACTORS AFFECTTO THE FERMENTED TIME, ALCOHOL CONTENT AND SENSORY QUAUIY OF PASSION FRUIT KEFIR PRODUCT
Nguyen Thi Lam Doan, Dang Thao Yen Linh, NgiQren Due Doan Summary
Kefir's fermented milk product is a yoghurt product with many microorganisms that help digestion and improve the human's immune system. This study focuses on investigation about some parameters including passion fruit juice content. Kefir microorganism rate and acid - stop - degree to fermented time, alcohol content and sensory quahty of the product. The results were indicated that Kefir yoghourt added with passion fruit was made by mixing freshly stenhsed milk with 6% passion finit juice and then fermented with 10% natural microorganisms Kefir to 95 Thomer (T) acid degree in 23h time fermentation, 2.2 (%V) alcohol content and good sensory quality. Besides, sensory evaluation was used to determine an addition of 3056 sucrose with the rate of 40% in fermented passion fiuit Kefir had resulted in high sensory quality Kefir yoghurt.
Keywords: Passion Unit, KeGr, yoghourt Ngudi phan bifen: GS.TS. Nguyen C^ng Khan Ng^ynhanb^: 30/11/2018
Ngay thong qua phan bien: 3/01/2019 N g ^ duyet dang: 10/01/2019
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 +2 - THANG 2/2019