Tgp chi Khoa hgc Tnr&ng Dgi hgc Cdn Tha Pbdn B: .\dng nghiip. Thin- san x d Cdng nghe Sinh bgc. 26 (2013) • 112-120
Tap chl Khoa hpc Tri/cJng Oai hpc Can Thd website: sj.ctu.edu.vn
KHAO SAT ANH HU'aNG CUA NGUYEN LI$U ( S C A , GELATIN VA MlTT DONG) DEN CHAT LU^QfNG CUA YAOURT TRAI CAY
Nguyin Minh Thuy', Hd Thanh Huang', Ngu>en Ai Thach' va Nguyen Phu Cudng' ' Khoa Ndng nghiip vd Sinh hoc tug dimg, Trudng Dgi hgc Cdn Tha
^ Cao hgc Cdng nghe Thirc phdm K18. Khoa Ndng nghiep vd Sinh hgc Ung dung Tntang Dgi hgc Can Tha Thong tin chung:
Ngdy nhgn-21/12/2012 Ngdy chdp nhgn: 20/06/2013
Title:
Effects of ingredients (milk gelatin and fruit Jam) on yoghurt qualily
TO- khda:
Yaourt, sira, gelatin, mui ddng. chdt lugng Keywords:
Yoghurt, milk, gelatin, jam, quality
ABSTRACT
This study was carried out to investigate (i) effect of fresh milk f4(h80%). skim milk powder (1-5%) and condensed milk (5^20%) on product quaUty: (ii) effect of gelatin percentage on physical properties
(water-holding capacity and texture) and sensory characteristics oJ yoghurt and (iii) effect of mixing fruit Jam (5-20%) on sensory attributes
of fruit yoghurt (FOB style or Sundae style). The results showed that the combination of condensed milk 10% with fresh milk 60% and skim milk powder 3% ga\-e yoghurt with high sensory scores flavor, texture and mouth-feel) and good qualily (less water release). The percentage oj gelatin 0.4% (220 Bloom) could be used to improve texture (tender and smooth), syneresis and mouthfeel of fruit yoghurt Addition of fruit jam (10-15%) into stirred yoghurt and IcQiredyoghurt (FOB-Fruit on Bottom) provided product with good taste, strong aroma and a good texture without water releasing.
T O M TAT
Nghien cdu diroc thuc hiin trin ca sd khdo sdt cdc dnh hudng (i) ty 1$
sira tuai (40-80%). ty li siia bgt (1^5 %) vd ty li sira dgc (5^20%) din chdt lugng cua yaourt: (ii) ty li gelatin den linh chdt vgt ly (do tdch nudc vd cdu trdc) vd gid ni cdm quan cua yaourt trdi cdy; (iii) ty li phdi tron mul trdi cd\' (5-20%) tdi gid trj cdm quan ciia yaourt dgng khudy va yaourt dang lap (FOB style hay Sundae style). Kit gud ngliien cuu cho thdy ty li phdi Iron cda sua tuai 60%, siia ddc 10% vd siia bgt 3% cho yaourt cd gid tii cdm quan (miii vi, cdu true tdt, cdm gidc ngon mi^ng) vd chdt lupng tdt (khdng tdch nudc). Gelatin su dung vdi hdm lugng 0,4%
(Bloom 220) giup cai thiin duac cdu trdc (min, lien kit chat, dg dinh tot), do tdch nudc rd cam gidc ngon miing cua yaourt trdi cdy Bo sung 10%
mdi ddng (Brix 45-50) vdo yaourt dgng khudy vd 15% vdo yaourt dgng ldp (FOB - Fruit on Bottom) cho sdn phdm yaourt trdi cdy cd vj ngon, miii thom vd cdu triic tdt, khong bj tdch nudc.
1 GIOI THIEU
Yaourt Id thuc pham Ien men lir sira, co nhieu chat dinh dudng va dugc tinh cao. Do ham lugng lactose thdp va chua mdt lugng Idn cac vi khuan lactic nen vaourl dl tieu hda va
ngon mieng hon so vdi siia (Hossanin va Islam, 2012). Nguyen lieu che bien yaourt Id sda bd tuai, chua nhieu chit dinh dudng thiet yeu cho con ngudi, Siia tuai giup cdi thien miii tham va gia Ui cam quan cua yaourt va la
Tgp chi Khoa hoc Tnr&ng Dai hoc Cdn Tha Ph&n B: Ndng nghiep. Thuy si d Cdng nghi Smh ligc. 26 (2013): 112-120 thanh phin chinh frong san xuit yaourt chit
Iugng cao. Tuy nhien, siia tuai cd ham lugng chat khd khdn^ beo thip, san lugng it va gid thanh tuong ddi cao d Viet Nam. Trong san xuit yaourt, lugng chit khd khdng beo (CKKB) cua dich sira trudc len men phdi dugc dilu chinh tir Z,2% tdi 16% (Tamime va Robinson, 1999). Do dd, cd the bd sung CKKB tu sira hot vdi nhilu ly do nhu giam gia thanh, tang hdm lugng CKKB va protein frong dich sira trudc len men, cai ihien do nhdt, do ben gel vd kha nang gid nudc cua yaourt (Sodini va Tong, 2006). Mgl nguyen lieu khdc CO the bd sung de lam tang lugng chat khd khdng beo la sua dac. Khdng cd su khac biet ve chat lugng giira hai each bd sung chat khd nay (Guzman-Gonzalez et al, 1999). Tuy nhien, hdu het sda dac d Viet nam deu la sua dac cd dudng. khi hdm Iugng dudng vugt qua 11% cd the tac ddng uc che su sinh trudng cua he vi khuan lactic (Tamime va Robinson, 1999), Do dd, cd nhieu khd khan xdy ra nlu chi su dung mdt loai nguyen lieu nhu sira tuai.
hoac chi sua bdt hay sua dac. Su dung kit hgp dich sua ban dau se cai thien dugc chat iugng san pham. Bd sung trai cay la phuang each da dang hod san pham yaourt, lang ham lugng cdc chat dinh duang va su hap dan cua san pham.
Dac tinh quan trgng ciia yaourt frai cay la cdu triic. gelatin cd the la mdt frong nhtmg tac nhan cai thien cau triic, ldm tang do nhdt, lam giam su tach nudc, cai thien cam giac ngon mi^ng va gidm dugc gid thanh san pham.
Trong cdng nghiep san xuat yaourt fren the gidi van su dung miit ddng lam nguyen lieu
Bang 1: Pfainmg phap xac dinh cac cfai tieu cfaat lirgng ciia yaourt
frong san xuat yaourt frai cay nhu yaourt FOB hay kieu sundae truyen thdng, ddy cung la san pham mdi d thj trudng Viet Nam. Do vay, muc lieu cua nghien cuu la xdc lap cac dilu kien tdi uu cho qua trinh san xudt yaourt trai cay chat lugng cao fren ca sd khao sat cdc \ eu td anh hudng tac ddng nhu cac loai sda ket hgp, gelatin va mut ddng Uai cay,
2 PHlTONG PHAP NGHIEN ClTU 2.1 Phuong tien nghien ciru
Dia diem nghien cuv
Phdng thf nghiem Bd mdn Cdng nghe Thuc pham - Khoa Ndng nghiep va Sinh hgc Ung dung - Trudng Dai hgc Can Tha.
Nguyen vgt lieu
Sua tuai Lothamilk, sua dac cd dudng Dutch Lady, siia hot tach beo (Instant Nonfat Dry Milk), gelatin, men gidng Vinamilk (1x10' den IxlO^cfti/g), 2 loai mut ddng (loai 60% mit va loai 80% thanh long rugt dd, 50°Brix).
2.2 Phuong pbap phan tich
Cac phuang phap phan tich chi lieu ly hda hgc va vi sinh cua nguyen lieu va san pham dugc the hien d Bdng 1. Danh gia cam quan sdn pham theo phuang phap QDA (Quantitative Descriptive Analysis), md ta timg thudc tinh cua sdn pham, bao gdm: mui, vi chua, luu vi chua, cam giac beo, do min va do tdch nudc. Mdi thugc linh dugc xay dung theo thang diem md td tu 0 den 5 (gid tri cam quan tir kem den tdt).
Chi tieu danh gia PhiTffng phap xac djnh pH
Dp im (%) Lipid (%) Duong long so (%) Protein (%) Dp cung (gram force) Dp tach nudc (%) Vi kfauin lactic (CPU g)
Su dung pH ke do true tiep khoi dong yaourt.
Xac dinh bang phuoiig phap say tdi khoi lugng khong doi, tir do am suy ra tong chat kho CO trong nguyen lieu.
Xac dinh bing phuang pfaap Soxhiet, TCVN 8125 :2009.
Xac dinfa dudng tong bing phuong phap Lane-Eynon.
Xac djnfa bSng phuong phap Kjedahl, TCVN 8125 :2009.
Chuan bi mau yaourt co chieu cao 20mm dupe cfaua uong hu nhua co dudng kinh 70 mm. Su dung may RHEOTEX, diu do hinh Uon (duong kinh 20 mm). Co dinh khoang each dam thung cua dau do vao mau la 4 mm.
Su dyng ma> l> tam Sigma 4K15 centrifuge (Suius AG, Gottigen. Germany). Yaouit (20-25g) dupe ly tam vdi toe dp 5000 rpm. nhiet dp 4°C uong 10 phiit (Rodarte et al, 1993 Ufch din tu Lee va Lucey. 2010).
Phuong phap dem mat so vi khuan lactic uen moi truong MRS Agar (Tamime \ a Robinson. 1999)
Tap chi Khoa bgc Tnt&ng Dgi hoc Cdn Tha Phdn B: Ndng nghiip. Thm- san vd Cdng nghi Sinh bgc: 26 (2013): 112-120 2.3 Quy trinh che bien yaourt trai cay
Djch sua sau khi phdi che dugc thanh triing d 80 - 85°C frong 1 5 - 2 0 phut (nhdm tieu diet cac vi sinh vdl xdm nhap frong giai doan phdi che va lam tang do ben gel cua sdn pham do tac dung nhiet thich hgp), lam ngudi djch sira xudng 40°C. Men gidng vi khuan lactic dugc bd sung vao dich sifa, thuc hien qud frinh u va dn dinh d 40°C. Trong qua trinh len men, theo ddi pH thay ddi tu 6.6 (ban diu) din pH 4,5 - 4,6 hay dg acid tir 0,7 - 0,75% thi kit thuc qua frinh. Khdi ddng dugc lam mat xudng nhiet do 20 - 25°C. Khao sat anh hudng ciia ly le mut ddng den yaourt dang khua> dugc thuc hien d giai doan nay (neu khuay mut ddng vao dich sda trudc len men cd the lam gidm kha nang hoat ddng cua vi khuan lactic). Yaourt dang idp, ty le mut ddng dugc rdt vao hop trudc len men. San pham dugc bao qudn d nhiet do 4 - 5°C. Phdn tich cac chi tieu chit lugng san phdm sau 3 den 4 ngay bdo quan.
2.4 Bd tri thi nghiem
2.4 1 Phdn tich thdnh phdn dinh du&ng cua nguyen lieu siia
Sira tuai (ST) su dung may phan ti'ch sua Milkotester de xdc dinh cac thdnh phin dinh dudng. Sua bgt (SB) va sira dac (SD) dugc xdc dinh do am. ham lugng beo, ham lugng protein (kiem tra lai ham lugng cac thdnh phdn ca bdn ghi fren bao bi).
Chi tieu phdn tich: do am, ham lugng beo. chat khd khdng beo. ham lucmg protein.
2.4.2 Anh hu&ng ciia ty le cdc logi sHa din chdt lucmg cua yaourt
i. Anh hudng ciia ly le sua tuai (40, 60.80%) va sua bdt (1.2.3.4.5%) (cd dinh sda dac 10%. % cdn lai la nudc) den chit lugng cua yaourt
ii. Anh hudng cua t\ le sua dac (5.10,15%) va sira bdt (1,2.3.4,5%) (cd dinh sua tuoi 60%,
"o cdn lai la nudc) den chat lugng cua yaourt Chi tieu phan tich (thi nghiem i vd ii)
Protein, do tach nudc, chit khd khdng beo vd gia frj cam quan.
iii, Anh hudng cua ty 1$ sOa dac (5,10,15,20%) (cd dinh sira nrai 60% va siia bdt 3 % . % cdn Iai la nudc) den iugng vi khuin lactic, thdi gian len men va gid fri cam quan ciia yaourt
- Chi tieu phdn tich (thi nghiem iii):
lugng dudng tdng. lugng vi khuan lactic, thdi gian len men, gid tri cam quan.
2 4 3 Anh hu&ng cua ty le gelatin (D; 0,2; 0,4;
0,6; 0,8%) den cdu true vd chdi luang cita yaourt trdi cdy dgng khudy (bo sung 10% mut dong)
Chi lieu phdn tich: do ciing, do tach nudc va gia tri cdm quan
2.4.4 Anh hu&ng tnja ty le mui dong bo sung (5. 10, 15. 20% tren tong khdi luang nguyen lieu sau khi phoi che hay tren long khoi lugng yaourt) vd cdch phoi hpp (dgng khudy hay dgng l&p) den chdt luang cua yaourt trdi cdy
Chi tiiu phdn tich: do tach nudc, gia trj cdm quan.
- Khoi luang mdu tren mpt dan vi thi nghiem: 2 kg
3 KET QUA VA T H A O LUAN 3.1 Thanh phan nguyen lieu sua
Sua tuai cung cap mgt lugng protein dang kl (2,5%.) va carbohydrate (4,3%) (Bang 2).
Dac biet, sira tuai cung cip huang vi thom ngon cho yaourt. Sua tuai cung chua nhilu loai protein cd hoat chit sinh hgc cao nhu immunoglobulins, lactoferrin, insulin... Thanh phdn carbohydrate trong sua tuai chu ylu la lactose cd y nghTa quan frgng cho su ddng tu yaourt. Tuy nhien, sua tuai chua ham lugng chit khd Ichdng beo thip (8,2%), can bd sung ngudn chat khd khdng beo tu sira hot (95,7%) va sua dac (65,6%) nhim cai thien chit lugng va cau tnic khdi ddns.
Tap chl Khoa b(>c Trutmg Dai hoc Clin Tlio- Phan B: Song nghiep. Thuy san va Cong nghe Sinh hoc 26(2011}: 112-120 Bang 2: Thanh phan dinh dudng cua cac loai sira
CAc thanh phan dinh duoTig Sira tuoi Sira dac Su^ hot Nuoc (%)
Chit beo (%) Chit kho khong beo (%) Protein (%) Carbohydrate (%)
Ghi cM: So ti^u the hien tren bang la gia tri Irung binh cua 3 tan do 8.8 ±0,02 3,0 ±0,01 8,2 ±0,02 2,5 ±0,01 4,3 ± 0,01
26,3 ± 0,03 8,1 ±0,02 65.6 ±0,03 6,7 ± 0,01 53,0 ± 0,02
3,0 ± 0.02 1,3 ±0,01 95,7 ± 0,03 20,0 ±0,02 67,0 ±0.04 3.2 Anh hudng cua ty le sua tuoi, sira bdt
va sira d^c den chat lugng yaourt 3.2.1 Anh hu&ng cua ty le siia bpt vd sira tuai
t&i chdt luoTig cua yaourt
Ket qua khao sat cho thay cung lugng sua bdt la 1%, khi tang ty le siia tuai them 20% thi
Bang 3: Anfa hudng cua ty Ie sua tucri (ST%) va sua bot (SB%) den faam lugng protein, b^m lugng CKKB ciia dich sua va dp tach nirdc ciia yaourt
lugng protein chi tang trung binh 0,6% (tir 2,2 lang len 2,8%) va CKKB tgng gin 2% (lii 10,8 tang 12,4%). Tuy nhien, khi tang ty Ie sua bdt them 3 % frong cung mdt Iugng sua tuai (60%) thi Iugng protein ldng 0,6% (lir 2,8 tang len 3,4%) va lugng CKKB tang gin 3 % (lu 12,4 lang len 15,3%) (Bang 3).
ST
%
40 40 40 40 40 60 60 60SB
%
1 2 3 4 5 1 2 3Protein
(%)
2,22,4 2,6 2,8 3 2,8 3,0 3,2
CKKB
(%)
10,8 11,8 12,7 13,7 14,6 12,4 13,4 14,4D§ tach nu4c (%) 26,0 18,0 14.0 9,0 6,4 15,5 10,1 3,0
ST
%
60 60 80 80 80 80 80SB
%
4 5 1 2 3 4 5Protein
(%)
3,43.6 3,4 3,7 3,9 4,1 4,3
CKKB
(%)
15,316,3 14,1 15,0 16,0 17,0 17,9
Do tach nuoc (%) 3.0 3,0 3.0 2,0 1.0 0.0 0,0 Dp tach nudc gidm ro ret khi tang lugng SB
va ST. Do ndng do chat khd khdng beo tang, ham lugng lactose se cao, giiip qua frinh len men tit, vd ham lugng protein cao giiip giam kha nang tach nudc cua yaoiut. Tuy nhien, ty Ie ST (60%) vd SB (3%) cd do tach nudc thdp va khong khac biet nhieu so vdi ty le ST-SB (60-4, 60-5, 80-1...). Kit qua thuc te cho thdy viec b6 sung siJa bdt la hieu qua trong viec cai thien hdm lugng chit kho. lugng protein va Igi nhuan cao ban siia tuai, giup cai thien dugc ciu tnic, gidm do tach nudc vd lang dp nhdl ciia sdn phdm (Sodini vd Tong, 2006). Khi t\
le sda tuai va sda bdt cang tang thi yaourt co ciu triic cang mjn vd tdt (Hinh I va 2). Tang t<- le sira tuai thi miii yaourt thom ban va tang cam gidc beo. San pham yaourt bo sung ty le sira tuai 60 va 80% khdng the hien su khac
biet rd ve mui vj va cau tnic. Khi tSng ham lugng stra hot thi mui vi yaourt khdng thay ddi nhtmg cam giac nham tang nhieu khi ty le sua bdt ldn hon 3%.
Utu v\ chua ^
Cam g a c b e o " ^ Mm VJOUH
(diaiMti'll
1 1
.-*•. J Vi cliua
; - . - o t w .
*Dcfnjn
Do tach nudc
H i n h 1: Anfa fairdng cua t>' If s u a tucri d e n gia t r j c a m q u a n ciia y a o u r t
Tap chi Khoa hoc Tnr&ng Dgi hgc Cdn Tha PhdnB. Nong nghiep. Thuy san vd Cdng nghe Smb hoc. 26 (2013) 112-120 protein, CKKB va do tach nudc ciia yaourt dugc the hien d Bang 4. Kel qua phan tich cho thay vdi cting lugng siia bdt la 1%, khi tang X\
le siia dac them 5% thi lugng protein chi tang frung binh 0,3% (ttr 2.5 tang len 2,8%) vd CKKB tang trung binh 3 % (ttr 9,2 len 12.4%).
Nhtmg khi lang ty le sira bdt tir I - 4% trong ciing mdt lugng sua dac 10% thi lugng protein tang 0,6% (tir 2,8 tang len 3,4%) va Iugng CKKB ldng 3 % (lir 12,4 tang Ien 15.3%). Do ndng dp chdt khd khdng beo tang va ham lugng protein cao giiip gidm kha ndng tdch nudc ciia yaourt. Tuy nhien, ty le SD 10% va SB 3 % ldm san phim cd do tach nudc thap vd khdng khac biet nhieu so vdi ty le SE)-SB (10 - 4, 1 0 - 5 , 15 - 1,..), Du lieu thu nhan cho thay bd sung sira hot hieu qua frong viec cdi thien ham lugng chat kho va lugng protein, nhung sira bgt nhieu cd the giam gia frj cam quan. Bo sung sua ddc cd dudng cd the cdi thien cau tnic va lam dju bdt vi chua sdn pham yaourt, nhung cung kliong the bd sung lugng ldn do co the ldc ddng uc che su sinh trudng cua he vi khudn lactic (Tamime va Robinson, 1999).
Hinh 2: Anh hudng ciia ty le su^ b6f den gia tri cam quan ciia yaourt
Ket qud lucmg lu nghien cuu ciia Drake (2003); Sodini va Tong (2006), cac tac gia cho ring sda hot giiip cai thien cau tnic, gidm do ldch nudc va tang do nhdt cua san pham, nhung lugng sira bgt bd sung cao se anh hudng den mui vi san pham.
3.2.2 Anh hu&ng cua ty le siia dgc vd siia bot den chdt lucmg cua yaourt
Ket qua khao sat dnh hudng cua ty le siia ddc (SD%) va sda bdt (SB%) tdi ham lugng
Bang 4: Anfa hudng cua ty If sira dac (SB%) va ty l£ su'a b$t (SB%) tdi faam lugng protein, ham lugng CKKB cua dich sua va dp tacfa nudc cua yaourt
SO
%
55 5 5 5 10 10 10
SB
%
12 3 4 5 1 2 3
Protein
(%)
2,52,7 2.9 3.1 3,3 2,8 3,0 3,2
CKKB
(%)
9,210,1 11.1 12,0 13,0 12,4 13,4 14,4
fid tach nuo-c (%) 33,0 31,0 19,0 20.0 18,5 17,5 14,0 3,0
SD
%
10 10 15 15 15 15 15SB
%
4 5 1 2 3 4 5Protein
(%)
3.43.6 3,1 3,4 3.6 3.8 4.0
CKKB
(%)
15.3 16.3 15.7 16,7 17.6 18,6 19,6D9 tach nuo'c (%) 4,0 3,0 3,0 2,0 1,0 0,0 0,0 3.2.3 Anh hu&ng ciia ty le siia dgc den chdt
lutmg cita yaourt
Anh hu&ng cua ty le sua dgc den lucmg vi khudn lactic vd th&i gian len men
Ket cjua khao sat anh hudng cua ham lugng dudng tdng frong yaourt trudc va sau len men, lugng vi khuan lactic sau qud uinh len men va thdi gian len men dugc the hien d Hinh 3 va 4.
Khi tang ham lugng sua ddc thi lugng dudng tdng so (lactose, sucrose,,) tang. Sau qua trinh len men. lugng dudng tdng co giam do vi khuan lactic su dung dudng lactose cho
cac qua trinh tang trudng va sinh acid lactic.
Theo Tamime va Robinson (1999) khoang 30% lugng dudng lactose dugc chuyen hoa thanh acid lactic sau qua uinh len men. Khi lang ty le stra dac tu 5-10% (lugng dudng tdng nhd hem \1%) thi lugng vi khudn tang do tang lugng dudng lactose va lugng dudng sucrose chua du uc che hoat dgng cua vi khudn lactic nen thdi gian len men ngin. Tuy nhien. ty le SD lang nhilu htm 15% (lugng dudng tdng Idn han 12.5%) thi lugng vi khuan lactic gidm va thdi gian len men keo dai (20% SD cd thdi gian len men > 14 gid).
Tap chi Khoa hgc Tnr&ng Dgi bgc Cdn Tha Phdn B: Ndng nghiep. Thuy s g nghi Sinh bgc: 26 (2013): 112-120
Hinh 3: Anh hirdng cua ti' If sua d | c d£n ham lugng dirdng t6ng trudc va sau len men, va anh fairdng den lugng vi kfauan lactic trong yaourt
^ Ijifoig duong tnidt lin men i^n i
—hatyng -ii hiw^ luetic ^au len men tCI'L' -gt
Hinfa 4: Anh birdng ciia tyi If sua dac den tfadi gian j
ISn men '
Khi lugng sucrose frong dich sira nhieu thi do hoat ddng cua nudc gidm va uc che qud frinh phdt triln cua khuin lactic, anh hudng tdi su san sinh acid lactic va hgp chat mui cua he vi khuin len men lactic. Su sdn sinh cac hgp chit mui (diacetyl) giam khi lugng sucrose uong yaourt tang tir ndng do 8% hay cao hon tiiy friudc vao gidng vi khuan (Chandan, 2006).
Ty le siia dac 10% khdng nhiJng cdi thien dugc ciu frtic ma vdn dam bao su sinh trudng va phdt friln cua khuan lactic.
Anh hu&ng cua ty le siia dgc den gid tri
cdm quan cua yaourt
Ket qua thi hien d Hinh 5 cho thay khi tang lugng sua dac ttr 5-20% thi vj ngpt tang va vj chua cua sdn pham gidm, do ldch nudc giam, do min tang, mau trang ciia yaourt gidm do sua dac cd mau vang (mau hinh thanh do phan ung Maillard trong qud trinh sdn xuat dudi tac dung nhiet). Tuy nhien, khdng co su khac biet nhieu v l mau sac vd miii vi giiia ty le 10-15%.
0 ty le 20% stra dac, vi qua nggt, it vi chua va it mui yaourt (do su sinh hucmg va acid tir vi khudn hi uc che bdi lugng dudng cao).
Hinh 5: Anfa faudng ciia tS If sua d|lc den gia tri cam quan cua yaourt
Tap chi Khoa Iwc Tnr&ng Dgi hgc Cdn Tha Phdn B: Ndng nghiip. Thuy san vd Cdng nghi Sinh hgc: 26 (2013). 112-120 3.3 Anh hudng ciia gelatin den cau true va
gia tri cam quan yaourt trai cay dang khuay
3.3.1 Anh hu&ng cua ty le gelatin den cdu true cita yaourt ti'di cay dgng khudy Yaourt dugc khuay frgn vdi mut ddng bang mdy khuiy tir de tao su ddng nhat giua khdi ddng yaourt va thjt qua. Khi ty le gelatin lang thi do cung chac cua yaourt cang tang (Bang 5). Tuy nhien, yaourt dugc bo sung 0,2, 0,4 va 0,6% thi khdng Ihl hien su khac biet y nghia ve dp cung. Yaourt dugc bd sung 0,4%
gelatin cho do cung chac tuong ddi hai hda va gia trj cam quan ve can tnic cao. Theo ly thuyet va kel qua ddnh gia cam quan, do cung ciia cac mau yaourt vdi ty le gelatin lu khdng bd sung va bo sung dan den 0,8% co su khac biet ro ret.
Bang 5: Anfa faudng cua ti' If gelatin den do cung va d9 tach nudc cua yaourt trai cay L* /«y» Do cung (gf) bo sung (%) ^ ^^^ '
0 0,2 0,4 0,6 0.8
f)d tach nudc (%) 14,55" 10,5^
17,78"'' 7,5^
20,11"'' 4.6*"
28.34*'' 4,0""
38,77' 0,4' Ghi dm: cdc Irung binh nghiem tbirc di kem v&i cdc chU cdi gidng nhau Iren cung moi cgl khdng khdc biit >' nghTa Ihdng tie. muc dgy nghta 5%
Khi tang lugng gelatin b6 sung, dp tach nudc CLia yaourt gidm ddng k l (/7<0,05), Cd le do tac dung giii nudc ciia gelatin khi lien ket mang vdi casein trong khoi ddng yaourt tang khi lugng gelatin bo sung tang. Tuy nhien, khi su dung lugng Idn gelatin (>0,5%) vdi do Bloom cao se dan den sdn pham co cau tnic gi6ng nhu dang thach (jelly) (Chandan, 2006) va xudt hien cam gidc la klii dn san phdm (Tamine va Robinson, 1999; Lucey, 2004).
3.3.2 Anh hu&ng cua ty le gelatin den gid tri cdm quan cua yaourt trdi cdy Kit qua khao sdt cho thiy t>' le gelatin tang tu 0 tdi 0,8% thi do ctrng sdn phim tang, dp ctmg cao nhat the hien vdi yaourt cd ty le gelatin 0,8% (Bang 6). Mau nay tao cam giac qua cung khi an (giong phomai). khdng mim.
mjn dac Irung cua yaourt nen cdc thudc ti'nh vl do mjn va cdm giac ngon mieng deu bi danh gia thap. Yaourt dugc bd sung 0,4 va 0,6%
gelatin cd gid tri cdm quan cao, min vd ngon mieng do tao dugc cau tnic phii hgp vdi san phim. Khdng the hien su khac biel ro (p<0,05) ve dp cung, min, do lien ket va cam gidc khi an giua hai mdu nay.
Bang 6: Kit qua thong ke anfa budng ciia gelatin (%) den gia trj cam quan ciia yaourt Gelatin Do
(%) cirug
»9 D6 Cam giSc liSn ngon mlfng kit (Mouthfeel) 0 2,50' 2.63" 2,50" 2,62"
0,2 3.50'' 3.13"" 3.00"" 3,00"
0,4 3,75**^ 4.25' 3.89' 4,25*
0,6 3,88'" 4,00'" 3,63*" 4,75' 0,8 4,25' 2.89" 4.25^^ 3,13"
Ghi chu- cdc Inmg binh nghiem thuc di kem vdi cdc chU cdi gidng nhau trin ciing mdi cgl khong khdc biit y nghia thdng ke. mirc ddy nghTa 5%
Hinfa 6: Be mat cau true b6ng min ciia yaourt v ^ ly If gelatin 0,4%
Do do yaourt dugc bd sung 0,4% gelatin vdi 220 do Bloom va 14% chdt khd khdng beo ctia hdn hgp sira trudc len men dugc chpn la mdu cd gia trj cam quan ve cau tnic la tdt nhat (Hinh 6). Ket qua thu nhan tuang tu vdi nghien cuu cua Supavititpalana et al. (2008), nong do 0,4% gelatin cd the cai thiSn ciu tnic va chit lugng cua yaourt.
3.4 Anh hudng cua p h u a n g thirc bo sung va ty le m u t ddng den gia tri cam quan va do tach nirdc cua yaourt trai cay Khi ty Ie mul ddng tang tir 5 tdi 20% thi vj ngpt cang tang va dp lach nudc cdng nhieu (Hinh 7). Lugng mut ddng cang nhieu (>15%) gay khd khan trong qud frinh khuiy. Do do nhdt ciia miit ddng cao va bd sung lugng ldn
Tap chi Khoa hoc Tnrang Dai hgc Cdn Tha PhdnB Ndngnghiep. Dim san vd Cdng nghe Sinb hoc 26(2013): 112-120 miit ddng thi can thdi gian khuiy dai mdi tao
su ddng nhat giua yaourt vd mut nhung cd the lam cho dp nhdt yaourt gidm va dp tdch nudc tdng. Ty Ie mut ddng thip (5%i), yaourt it tach nudc (Bang 8) nhung miii vi khdng dac trung cua trdi cay nen gid trj cam quan khdng cao.
20% mut ddng bd sung vdo yaourt cd the lam san pham bj tdch nudc nhieu vd mat vi chua cua yaourt. Ty le miit ddng bo sung tu 10%
den 15% cho sdn pham cd gia frj cam quan cao nhat (chua-ngpl hai hda) vd miii vi dac tnmg (frai cay-yaourt).
Mui thmii die tnni^ ciia tnu ca>'
Hinh 7: Anfa fairdng cua ty If mirt dong den gid Iri cam quan ciia yaourt trdi cSy
De giam dp tach nudc, han chl su pha vd cau fruc do qua trinh khudy, nghien cuu con khdo sdt dang yaourt dang Idp hay cdn gpi la yaourt FOB (yaourt bd sung Idp mut ben dudi Idp yaourt). Kit qud thuc t l cho thiy ty Ie mut dong va dang phdi hgp miit ddng vao yaourt dnh hudng den gia tri cam quan cua sdn pham (Bdng 7).
Bang 7: K£t qua tfadng k£ anfa faudng ciia phirong tfairc bo sung va ty If mut dong den diSm ira thiefa va do tdch nudc ciia sSn pham
Maud$cmnig ciid iTdi cay Ty lc nnd
... ioi»4
- — - [ • ; %
Dang phoi hop - % milt K - 5%
K - 1 0 % K - I 5 % K - 2 0 % L - 5%
L - 1 0 % L - 1 5 % L - 2 0 %
fiiSm ua thich 5.9"
7,6' 6,9"
5.5""
5.3"
7,5=
8,1' 8,3'
Dg tach nu<3^c
(%)
3.2"3,5"
4,8"
7.2' 0.6"
1,4"
1,6*
1.5"
Chi chu. cdc trung binh nghiem thirc di kem v&i cdc chti cdi gidng nhau trin ciing mdt cgl khong khdc biily nghTa thdng ke. mtic doy nghTa 5%.
Doi vdi yaourt dang Idp (L), ty le bd sung mut ddng tu 10 tdi 20% deu co diem ua thich cao. Tuy nhien lugng mut ddng tu 15-20% cho hinh dang san phdm hap dan han va khdng co su khac biet nhilu (p<0,005) v l kit qua danh
\'i chua
gia cdm quan. So sanh yaourt dang khuay vd dang Idp thi sdn pham dang ldp (L) cd diem cdm quan cao han va do tdch nudc thap han (Bang 7) yaourt dang khuay do yaourt dang ldp khdng lam pha vd cdu tnic tu nhien cua yaourt (Hinh 8).
Hinh 8: San phim yaourt thanh long rugt do (a), yaourt mit (dang Idp-FOB) (b) va yaourt
thanfa long ruQt do dang khuay (c)
Tap chi Khoa hgc Tnr&ng Dgi hgc Cdn Tha nB Nong nghiep. Thtiy sdn vd Cdng nghe Sinh hgc: 26(2013): 112-120
4 KET LUAN
Thanh phan nguyen lieu san xuat yaourt co gid tri tdt va chi phi thip la 10% sua ddc, 60%
siia tuoi va 3% siia hot. Lugng gelatin bd sung 0,4% giup cai thien ciu tnic ciia yaourt frai cay va tang gia trj cam quan cua yaourt trai cay, Khi bd sung 10% mut ddng so vdi sua chua thi san pham cd mau sac va mui vj dac trtmg cua frai cay, cdu tnic tot va dp cam quan cao. Ddi vdi yaourt dang Idp (FOB), lugng mut ddng bo sung 15% cho san pham cd chit Iugng cao. So sanh san pham dang khudy va dang FOB, thi dang FOB cho trang thai ben ngoai hap ddn va It ldch nudc hem dang khuay.
TAI L I | U THAM KHAO
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2. Guzman-Gonzalez M., Morais P.. Ramos M., Amigo L., 1999. Influence of skimmed milk concentrate replacement by dry dairy products in a low fat set—type yoghurt model system. 1:
Use of whey protein concenfrates, milk protein concentrates and skimmed milk powder, J. Sci, FoodAgric, 79:1117-1122,
3. Hossanin N. Fakruddin and Islam N., 2012.
Quality Comparison and Acceptabilit of Yoghurt -with Different Fruit Juices. J Food Process Tecnol., 3-8.
4. Lee W.J. and Lucey J.A., 2010. Formation and Physical Properties of Yogurt. Asian-Aust, J.
Anim. Sci., Vol. 23, No. 9: 1127-1136.
5. Lucey J.A,, 2004. Formation, structural properties and rheology of acid-coagulated milk gels. In Cheese: Chemistry, Physics and Microbiology, Vol. 1, General Aspects (Ed. P.
F., Fox P. L. H. McSweeney, T.M. Cogan and T. P. Guinee), 3rd ed, Elsevier Academic Press, London, pp 105-122,
6. Sodini I and Tong P.S, 2006. Milk and milk- based ingredients. In: Chandan, RC, White, CH, Kilara, A, Hui, YH, editors, Manufacmring Yoghurt and Fermented Milks, Ames: Blackwell Publishing, p 167-1783.
7. SupavitiQjatana P. Wiijantoro T.Y.
Pichartsrangkoon A., Raviyan P., 2008.
Addition of gelatin enhanced gelation ofcom- milkyoghurt. Food Chemistry 106:211-216.
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