KHOA HOC CONG NGI
AlVH HUQMG CLIA THOI GIAIXI XLT LY A X I T XITRIC Tl£lM BAO OLIAIXI DEIXI MOT SO OAC TiiMH LY HOA CUA
OLiA HOIVG THACH THAT
Nguyen Thi Hanh', Vu TTii Nga^
TOMTAT
Muc dich cua nghien cuu nay nh^m xac dinh anh hucmg cua che do xii ly dung dich axit xitric den mot so dac tinh ly hoa dac tnmg ciia qua h6ng Thach That {Diospyros kakiThunh) de tir do xac dinh che do tien bao quan thich hpp doi vol loai qua nay. Qua hong Thach That sau khi duoc thu hai cr do chin thich hop tien hanh xu ly trong dung dich axit xitric b pH 3,0-3,5; nhiet do SCC vin thoi gian lan luot la 5.10,15,20 phiit va mot mau doi chung. Cac dac tinh ly hoa dugc xac dmh bao g6ni: do cung, mau sac. ham luong chat kho hoa tan tong s6 (TSS), ham lugng ducmg tong sd, ham luong axit tong so, ham lugng tanin, ham lugng vi smh vat tong s6 va chat lugng cam quan ciia qua hdng. Ket qua cho thay Ihdi gian xii ly dung dich axit xitric thich hgp nhM la 10 phiit de lam tang hieu qua bao quan ciia qua hong.
Tii khoa: Qua hdng, Thach That, axit xitric, tiSn bao quan.
1 . BAT VAN H
Qua hong Thach Tliat (Diospyros kaki Thimb.) la loai h6ng phuong Dong, co noi gpi la hong a nhiet dm, hong Nhat Ban. Day la loai qua cd gia tri dinh duong cao, nang suat on dinh nen mang lai gia tri kinh te to Ion. Hong chii yeu duoc su dung voi muc dich an tuoi. De keo dai thoi gian su dung cua qua hong, ngiroi ta thuong ket hgp nhieu phirong phap de nang cao hifeu qua bao quan. Mot trong nhimg bien phap dtrgc su dung hien nay la k^t hgp sii dung axit hiju co nhir xitric, malic, axetic trong giai doan ddu sau do sii dtmg cac bien phap hep theo nhir bao quan lanh, bao goi MAP, khi dieu bien...
Viec xu ly hang dimg dich axit xitric ket hgp vol xu ly nuoc nong trong giai doan ti^n bao quan mang lai nhifeu tac dong co lgi da dugc cac tac gia chi ra a nhi^u nong san noi chimg va qua hdng noi rieng. Xu ly nhiet lam giam tinh nhay cam ciia qua hdng voi hien tugng ton thirong lanh, khu triing va duy tti chat lugng sau thu hoach cho gidng hdng Fuyu, h6ng Rojo Brillante, h6ng Karaj... (Mousa RasouU va Orang Khademi, 2014; Woolf va cs., 1997;
Burmeister va cs., 1997; Lay-Yee va cs.. 1997; Besada va cs., 2008b; Khademi va cs., 2012a; Ahmet Erhan Ozdemh va cs., 2009). Cac tac gia da khao sat trong khoang nhiet do xu ly 47 - 54"C vdi thai gian khac
nhau va theo doi bi€u hien rdi loan sinh hoa, n&m benh cung mot so chi tieu nhu: do ciing, do axit, hao hut khdi luong...d^ minh chiing cho hieu qua ciia phuong phap nay [3,4, 8,9).
Bai Viet nay ttinh bay k^t qua nghien cuu anh huong ciia thai gian xii ly dung dich axit xitric den mgt so dac tinh !y hda qua h6ng Thach Tliat (Diospyros kaki Thimb.) trong giai doan tien bao quan. Qua h6ng sau thu hoach CMOC nhiing trong dung dich axit xitric a pH 3,0-3,5; nhiet dp 50**C vdi thcri gian khac nhau va theo ddi su bi&n doi mgt so chi tieu trong 8 ngay sau do. K^t qua cua nghien cuu nay da chi ra che do thich hgp de xu ly qua hong truoc khi su dung cac phuong phap bao quan tiep theo.
2. NGUYBU LEU VA PHUDNG PHAP NGHCV CUU 2.1. Nguyen U§u
Nguyen Ueu qua hdng {Diospyros Aafo'ITiunb.) thuoc gicing hong TTiach Thsit dugc trdng va thu hoach tai huyen Tan Yen, Bac Giang. Qua hong dugc lay mhi vao chinh vu thu hoach thang 10 nam 2017 va 2018 khi vo qua co mau vang hoi xanh, mau vang
> 80%, mau vang hcri xanh a duoi qua < 20%, dat 100 - 110 ngay tuoi ke tir khi dau qua.
' Vien Cong nghe Sinh hgc va Cong nghe Thuc pham.
Tnrcmg Dai hgc Bach khoa Ha Noi
- Vien Co dien nong nghiep va Cong nghe sau diu hoach Email: [email protected]
Hinh 1. Qua hong TTiach That a dp tudi thu hoach
62 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 7/2019
KHOA HOC C d N G NGHfe
H6ng dupe thu hai nhe nhang vao buoi sang trong di^u kien kho rao. Dimg keo cat each cudng khoang 1 cm, bo la. Xep qua vao trong thimg xop due 16 va van chuyen ve phong thi nghiem. Qua duoc bo tri thi nghifim tt-ong ngay.
?.2. Phirong phap nghidn ciiu 2.2.1. Phuong phap bd tri thi nghiem Nguyen heu hong sau thu hoach dugc dinh lirgng 3 kg/mSu, tien hanh xir ly bang dung dich axit xitric b pH 3-3,5, nhiet dp 50^0 voi thoi gian nhung khac nhau (5,10,15 va 20 phut) tuong ling vol 4 mhi thi nghidm aN4.1; TN4.2; TN4.3 va TN4.4) va mhi doi chimg TN4.0; khong xu ly axit xitric. Thi nghiem dugc b .ri hoan toan ngau nhifen, mdi cong thiic lap lai 3 Idn va 6 ciing mgt thai diem. Cac mSu sau khi xu ly duoc de rao nuoc, xep vao khay chiia mau, luu mhi b dieu kifen thuong (nhifet do 25-30°C, dp am 65 - 75%). Theo doi va tien hanh lay mlu phan tich trong 8 ngay, tdn suat 2 ngay/lan. Cac chi tieu chat lupng dugc danh gia gdm: Dp cung G^g/cm^, su thay d6i mau sdc (AE'^b), ham lupng TSS C*Bx), ham luong duong tdng so (%), ham lupng axit hiru ca tong sd {%), ham lupng tanin (%), chat lugng cam quan, ham lirgng vi sinh vat tong so (cfu/g) va ty le thdi hong
{%)•
2.2.2. Phuong phap phan tich chat luong a. Xac dinh dp ciing thit qua bang may do do cung FT 327 (Itaha). Sii dung dau do duong kinh 8 mm, khoang each dam xuyen la 1cm, don vi kg/cm^
b. Xac dinh mau sdc vd qua bang may do mau Minolta CR-300 cua Nhat. Sir thay doi mau sdc (AE* J dugc xac dinh theo cong thiic:
AEl, = yliAL')^ +(Aa")- +(AZ»')'
Trong do: AL*= L'-L; Aa'- a'-a; Ab'= b*-b; Trong do: L bieu thi cho cuong dp mau co gia tri tir 0 (den) den 100 (trdng); a bi^u thi cho dai mau tir xanh la cay (-60) den do (+60); b bieu thi cho dai mau tir vang (- 60) den xanh nuoc bien (+60).
c. Xac dinh ham lupng tanin bdng phuong phap KaLpecmanganat (%)
d. Xac dinh ham lugng axit tong sd theo phuong phap chuan do bang NaOH O.IN (%)
e. Xac dinh ham lugng duong tong sd theo phirong phap Graxianop (%)
f. Xac dinh ham luong TSS bdng chiet quang ke CBx)
g. Danh gia chat lupng cam quan theo phuong phap cam quan mo ta
h. Xac dinh ham lupng vi sinh vat tong sd bang phuong phap dem khuan lac (cfu/g)
i. Ty le thoi hong (%) la ty le phan tram khoi lupng qua bi hong tren khdi lugng qua cua mau ban dau voi khdi lupng mdu khong thap hon 1000 gam.
2.2.3. Phuong phap xuly sdheu
Ket qua thi nghifem duoc phan tich ANOVA va kiem dinh LSD (5%) bang phan mem tiidng ke SAS 610.
3. KET QUA VA THAO LUAN
3.1. Anh huong ciia Ihdi gian xu ly axit xitric d^n dp Cling, m^u s ^ va ch^t lugng cam quan ciia qua h6ng
Anh hudng cua xir ly dung dich axit xitric den su thay doi dp cung, mau sdc va chat lupng cam quan ciia qua hdng dugc the hien trong bang 1 va hinh 2.
Xif ly voi nuoc nong co tdc dung khii tning, duy tri chat lugng qua tiong qua ttinh bao quan va lam giam ty le tdn thuong lanh (CI) cua qua hong [5, 6, 7.
9]. Bang 1 cho thay mau ddi chimg TN.4.0 va TN.4.4 CO dp Cling giam nhanh va qua bi mem (do ciing <0,5 kg/cm^ tir ngay thii 4 sau xir ly. Mhi TN.4.3 co do Cling giam kha nhanh va qua bi m6m a ngay thit 8 sau XLf ly. Mau TN.4.2 duy tri do cimg tdt nhat, sau do la 1^^.4.1, sau 8 ngay qua vdn duy tii duac tiang thai vol do cimg lan luot la 3,6 va 3,1 kg/cm^. Su sut giam dp Cling cua qua hong la do tiong qua trinh chin, protopectin chuyen thanh pectin hoa tan, lam cho hen k^t giira cac te bao va cac mo bi yeu di lam cho qua hi mem. 6 mdu doi chimg va mdu xir ly 20 phut tt-ong axit xitric, qua tiinh chin diln ra manh me hon, cac chat pectin bi phan buy den axit pectic va metanol lam cho qua bi nhun va cau tnic hi pha huy.
Qua hong sau thu hoach cd mau vang hoi xanh, qua rdt Cling va chat, chua nggt. Ngay sau khi xii ly.
mdu TN.4.3 va TN.4.4 da xuat hien cac vet ran a quanh niim qua va chay doc theo chi^u dai qua, mdu TN.4.4 bl ran nhieu hon TN.4.3. Cdc mdu cdn lai khong xudt hien vet ran. Ket qua nay cung tuong ddng voi nghien ciiu cua Ahmet Erhan Ozdemir va cs. (2009) khi xir ly nuoc nong cho qua h6ng 'Rojo
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 7/2019 63
KHOA HQC CONG N(
Brillante' [3]. Theo tac gia, xir ly nude ndng giup lam giam qua trinh mgm hoa o qua doan ddu cua do chin (mau vang cam), nhung lai gay ra hien tupng mit vo' va bi^n mau nau ovo qua h6ng co dp chin tmng binh hoac da chin (mau cam va mau cam do). O ngay thii 8 sau xii ly, mdu TN.4.0 da chin do, TN.4.4 qua da chin do hoi cam, m^m va rat ngpt; mdu TN.4.3 qua bdt ddu chin, co mau cam dam hoi do, vi chat va hoi nggt. Rieng hai mdu TN.4.1 va TN.4.2 vdn duy tri tdt chdt lugng qua, mdu co mau vang, ciing, rat chat va chua cam nhan duoc vi ngot.
Ket qua danh gia cam quan ve mau sac cua cac mdu ciing tiiang ddng voi su thay doi mdu sac cua qua hdng tiiong qua vific xac dinh chi s6 AE ^b- ^et qua ti-en hinh 2 cho tiiay, mdu TN.4.1 va TN.4.2 duy tii chat luong mau sdc cua qua tot nhat. the hien qua gia tri AE^^ nhd nhat, nguoc lai mdu TN.4.0 va TN.4.4 gia tti AE',b tiiay doi Ion ttrong img voi qua tiinh chin ciia qua 6 ngay thir 8 sau xu ly. O ngay cudi cua qua trinh bao quan, AE ab cua cac mau TN.4.0; TN.4.1; TN.4.2; TN4.3 vd TN.4.4 Idn lugt la 51,65; 4,90; 4,18; 26,61 va 44,36.
Bang 1. Anh huong cua thoi gian xuly axit xitric dfe dp ciing va chat lirgng cam quan ciia thoi gian bao quan
Chi tieu
1. D6 Cling (kg/cm^
2. Cam quan Thoi gian (ngay)
0 2 4 6 8 0
8
qua hong tt-ong M a n thi no-hipm
TN.4.0 3,9 + 0,2 1,9+0,3
<0,5
<0,5
<0,5
TN.4.1 3,9 ± 0,2 3,8 + 0,1 3,6 + 0,1 3,3 + 0,2 3,1+0.2
TN.4.2 3,9 + 0,2 3,9 + 0,1 3,8 + 0,1 4,2 + 0,1 3,6 + 0,2
TN.4.3 3,9+0,2 3,5 + 0,1 2,7 + 0,2 1,1+0,3
<0,5
TN.4.4 3,9+0,2 1,3 ±0,3
<0.5
<0,5
<0,5 Niim vang xanh tuoi. Qua mau vang hoi xanh. Qua cting gidn, vi rat chat. Miii chuaro
- Qua chin do, rat m^m, cang bdng.
- Vl nggt, thom, hoi chat - Vd qua khdng bl ran
- Qua mau vang, Cling, gidn, cang bdng.
- Vl rat chat, chua nggt - Vd qua khong hi ran
- Qua mau vang. Cling, gidn, cang bdng.
- Vi rat chat, chua ngpt - Vd qua khong bi ran
- Qua mau cam dam hoi do, m6m, cang hdng.
- Vi chat, hoi ngot, hoi thom - Vd qua bi ran nhe
- Qua chin dd hoi cam, mem, cang
Ddng.
- Vi ngot, thom, tioi chat
• Vd qua hi ran nhieu
—^ar" TN.4.2
Thcfigian (ngay)
Hinh 2. Anh hudng cua thdi gian xu ly axit xitric d^n su thay d6i mau sac cua qua hong 64 NONG NGHIEP VA PHAT TRIEN NONG THON-KYI -THANG 7/2019
KHOA HOC CONG NGHE
Hinh 3. Su thay ddi mau sac cua qua hong theo thdi gian bao quan Cd th^ nhin thay cu the sir bien doi mau sdc b
cac mdu ttong qua trinh bao quan dugc minh chiing d hinh 3. Cac mdu TN.4.0 va TN.4.4 cd su tiiay doi mau sdc ro ret sau 8 ngdy hao quan. Mdu TN.4.3. cd sir ihay ddi mdu sdc cham hon. Trong khi dd 2 mdu
TN.4.1 va TN.4.2 vdn duy tri duac mau sdc so vdi ngay sau khi thu hoach.
3.2. Anh hirdng ciia thdi gian xu Ij^ axit xitric d^n su bien ddi mdt so chi tieu hda 1^ cua qua hong
3.2.1. Ham luong chat khd hda tan tdngsd
2 4
22
2 0
•g 3. 18
*" 16 14 12
i
4
1
0 2
T h o ' i g i a n (ngay) 6
.^---^
8
- - » " T N . 4 . 0 - « » - T N . 4 . 1 - * — T N . 4 . 2 TN.4.3 - * — T N . 4 . 4
Hinh 4. Anh hirong cua thdi gian xft ly axit xitric d & ham luong chit khohoatan tdng socua qua h6ng r;,„„ ' .u .>'•',• u .u ' • ' qua. Ham lumg TSS tang trong thm gian bao quan.
Cung vol su thay doi ve kich thuffc, mau sac, ^ ,. - ^ > T . T . - . ^ L L - . t r = n „ n , i i ' 't,--' A'- . .1.. 1, I.' >,. 1. • Nguyen nhan la trong qua trmh chin, tmh bot trang thai la su bien doi cac thanh phan hoa ly cua ^^n^y^'
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 7/2019 65
KHOA HOC CONG NG chuyen hoa thanh duong nen luong duong bi phan
huy trong qua trinh ho hap se thap hon so vol luong duimg tao thanh din den ham luong TSS tang [1, 2].
Mau doi chiing co ham luong TSS tang manh nhat (tang tir 15,4% din 22,1% sau 8 ngay), sau do laTN4.4 (21,6%), tiep den la TN4.3 (19,5%). Hai mau TN4.1 va TN4.2 CO muc do tang ham luong TSS cham hon ca.
Sau 8 ngay bao quan, gia tri nay dat 18,8% va 18,4%.
Dieu nay chiing to viec xu ly dung dich axit xitric 6 thai gian thich hop co tac dung lam cham lai qua trinh chin 6 qua hong Thach That.
3.2.2. Ham luong duong tong sd
Ham luong duong tong so quyet dinh den chat luong an tuoi cua qua hong. Hinh 5 cho thay ham
lugng dudng tdng sd tang nhanh trong thoi gian chin 6 tat ca cac mJu. 6 mSu ddi chiing, sau 8 ngay bao quan ham luong duong tdng sd la 14,63%. Cac mau xu ly axit xihic gia tri nay lan lugt la 13,69%; 13,91%;
14,08% va 14,27% hiong ling vdi TN4.1; TN4.2; TN4.3 va TN4.4. Didu nay chiing td tdc dp chin cua m5u TN4.1 la cham nhat dan ddn ham lugng dudng tdng sd tang it nhat Hdng la loai qua hd hip dot bien nen trong qua hmh chin cd su bidn ddi hnh bdt thanh dudng. Dung dich axit xitric cd tac dung lam cham qua trinh chm ciia qua nen lugng dudng dugc tao thanh cua cac mJu cd xir ly axit thap hon mSu ddi chiing.
1 5
g
1"
.1
2 4
Tho-i gian (ngay) 6
^..--^ —.—TN.4.0
^^^..''^^^ —m TN.4.1
•^^Z"-"'^ — * — T N 4 . 2 TN.4.3
—.— TN.4.4
8
Hinh 5. Anh hirong cua thdi gian xii ly axit xitric d^n ham lupng dudng tong s6 cua qua hong 3.2.3. Ham lugng axit hdu ca tdngsd
° 3 i
t 0.2
^ 0.15 ;
_^
B O I .roV T
r--
1— . ^ T N . 4 . 0
• T N . 4 . 1 T N . 4 . 2 T N . 4 . 3
— ~ — T N . 4 . 4
I Tho-i gian (ngay)
Hinh 6. Anh hudng cua thdi gian xu ly axit xihic d^n ham lupng axit hiiu ca tdng s6 ciia qua hong ,^.-. ' I,-- ' A. i,i^k fi ^g ^hi v^ r^riCT ham 0,12%. Troug khi cac mdu cd XU ly axit xiti-ic SU suy Ket qua nghien cuu o hmh b da cni ra rang nam ^ , ,-- , ,. • A. - '
,~ .. -, . .-•. , -„ „ ^ „ t^„„„ th™ giam nay dien ra cham hon. O mau xu ly 5 va 10 uong axit tong so giam o tat ca cac mau trong thm \ / • , ^^
gian bao quan. Miu dd, chung cd ham luong axit P h * ham lugng axit huu co tong so deu con la, la giam manh nhit, sau 8 ngay bao quan chi sd nay la WS''- » - ™ u con lai co ham luong axit tong sd sau
** 8 ngay bao quan la 0,15% va 0,13% tuong ling vdi thdi 66 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 . THANG 7/2019
KHOA HOC CONG NGHE gian nhting hong dung dich xitric la 15 va 20 phiit.
Dieu nay cd the giai thich la do axit hiiu eg la nguyen li^u Irong qua trinh hd hap cda qua, trong thdi gian bao quan qua trinh nay tiep tuc xay ra din den ham luong axit giam di. Su khac nhau ve bien ddi ham lirong axit giiia cac miu thi nghiem cung cho thiy dung dich axit xitric cd tac dung lam cham lai qua trinh hd hip g qua hdng.
3.2.3. Ham luong tanin
Tanin gay ra vi chat d qua hdng. Qua cang chin, ham lugng nay cang giam manh. Hinh 7 cho thay
ham lugng tanin d miu ddi chimg giam manh nhit (cdn lai 0,8% sau 25 ngay bao quan), cac miu xu ly axit cd tdc do giam cham hon (gia tri ham lugng tanin lin lugt la 9,21%; 7,75%; 2,93% va 0,48% hiong img vdi cac mau xii ly axit xitric hong thdi gian 5; 10;
15 v i 20 phiit sau 8 ngay bao quan). Miu TN4.1 cho do giam ham lugng tanin la cham nhat hong sudt thdi gian bag quan. Dieu nay chung td dung dich axit xihic cd tic dung lam cham qua trinh chin, keo dai thgi gian bag quan qua hdng.
• TN - — T N -^sS—TN
— TN T N
4 4 a
^
O 1 2 3
'
Hmh 7. Anh hudng a i a thdi gian xu ly axit xitric d^n h ^ lupng tanm cua qua h6ng Su giam ham lupng tanin cua qua hdng da duoc
nhieu tac gia nghien cuu trudc day [10, 11, 12].
Trong qua trinh hd hap cua qua tao ra ethylen d ndng dd cao da kich hoat qua trinh chin vd su mdt nude d thanh te bdo. Viec giam kha nang tham than ttong khong bdo lam mat nude te bao, do dd tanm hoa tan chuyen thdnh dang khdng hda tan va loai bd chat chat khdi qua hdng.
3.3. Anh hirdng ciia thdi gian xu ly axit xitric den ham lupng vi sinh vat tdng sd va ty 1$ thdi hong cua qua hdng
Bang 2. Anh hirong cua thdi gian xu ly dung dich axit xitric d^n ham lupng vi smh vat tong sd va ty \h thdi hong ciia qua hdng
Xu ly qua hdng vdi nude ndng ngodi tac dung duy tri chat lupng qua cdn cd tac dung khu trimg [3, 8). Ngodi ra. dung dich axit xitnc d" pH 3,0-3,5 cung cd tac dung han che su phat tnen ciia vi sinh vat, tir dd giam ty le thdi hdng trong qua ttinh bao quan.
Anh hudng cua thdi gian xu ly qua hdng bdng dung dich axit xitric d 50*^6, pH 3,0-3,5 den su bien ddi ham lupng vi sinh vat tdng sd (TYC) va ty le thdi hdng duoc the hien ttong bang 2.
Chi heu
rvc
(cfu/g) Ty le thdi hdng (%)
Thdi gian (ngay)
0 8 8
Miu thi nghiem TN.4.0
6,75x10"
2,48x10"
11,5
TN.4.1 1,73x10=
l,23xlO<
5,5
TN.4.2 1,55x10=
8,20 xlO=
3,7
TN.4.3 1,31x10' 6,61x10=
1,2
TN.44 1,03x10=
6,35 xlO=
0,5 v^. ' . . . • . ., .' • 1 - .^_ J 1 ^u dang ke den su bien ddi cua TVC. Miu hdng ban diu
Ket qua nghien cuu cho thay xu ly vgi dung dich '^'"'*' *^
cd TVC khoang 6,75x10" (cfii/g). Ngay sau khi xii ly.
axit xihic d pH 3,0-3,5; 50°C cd tac dung han che su
phat trien ctia TVC va thdi gian xu ly cd anh hudng TVC cua cac mau TN4.1; TN4.2; TN4.3 va TN4.4 giam nhanh xudng 1,73x10=; 1,5.5x10'; 1,31x10= va NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 . THANG 7/2019
KHOA HOC CONG NG
1,03x10= (chi/g). Hieu qua khir khuan ty le thuan vdi Treatment on Softripening in Japanese Persimmon thdi gian xu ly. Sau 8 ngay bao quan, miu TN4.4 cd (Diospyros kaki Tbunb.) 'Saijo' Fruit Horticultural TVC thap nhat, sau dd lan lugt la TN4.3; TN4.2 va Research Qapan), VoL 7 . Xo. 1, p. 111-114- TN4.1. Miu ddi chiing TN4.0 cd TVC phat tiien rat g Khademi, 0., Zamani, Z., Poor Ahmadi, E.
nhanh len 2,48x10" (cfu/g) d ngay thii 8 sau xii ly. ^ ^ Kalantari. S. (2013). Effect of UV-C radiation on Ket quil danh gia ty le thdi hdng ciia qua hdng sau i
ngay hao quan cung cho thay d mau ddi chimg (TN4.0) cd ty le cao nhat (11,5%); Cac miu cd xu ly dung dich axit xitnc ty le nay thap hon dang ke (5,5%; 3,7%; 1,2% va 0,5% hiong ling vdi TN4.1; TN4.2;
TN4.3 va TN4.4). Dieu nay chiing td axit xitric da cd tac dimg ban che su phat trien a i a cac tac nhan gay hu hdng cha qua hdng (nam men, nim mdc) din den ty le thdi hdng cung giam di sau 8 ngay bao quan.
4.KEILUMI
Nhu vay, ket qua nghien ctiu vd danh gia anh hudng cua xu ly vdi dung dich axit xitnc g pH 3-3,5;
nhiet dg 50''C vdi thdi gian nhiing khac nhau cho thay nhung qua hdng Thach That trong thdi gian 10 phut se duy tri chit lugng hdng tdt nhat trudc khi tidn hanh cac phugng phap bao quan tidp theo.
TAIUEUHMMKIUO
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N O N G NGHIEP VA PHAT TRIEN N O N G THON - KY 1 . THANG 7/2019
KHOA HOC CONG NGHE
THE EFFECTS OF ACID CITRIC PR&STORAGETREATMENTTIME ON SOME OFTHE SPECIFIC PHYSISICOCHEMICAL PROPERTIES OF THE THACH THAT PERSIMMONS
Nguyen Thi Hanh^ Vu Thi Nga^
'Insti'tute of Biology and Food Technology, School of Hanoi University of Science and Technology
^Institiite for Agricultural Engmeering and Post Harvest Technology Summaiy
The purpose of this study was to determine the effects of citric acid solution on some of the specific physicochemical properties and maturity of the Thach That Persimmons {Diospyros kaki Thunb.) for proposing the most appropnate prestorage for this fruit. The Tliach That persunmons were picked up at the most suitable maturity were dipped in the citric acid solution at pH 3.0-3.5; 50°C with the ttme of 5; 10; 15; 20 minutes compared to a conttol sample. Physical and chemical properties were specified, mcludmg:
hardness, color, total soluble soUds content (TSS), total sugar content, total acid content, tannin content, total microorganisms content and sensory quality of persunmons. The resuhs showed that the best time to dip the Thach That persimmons to citnc acid solution is 10 minutes to increase the persimmons storage efficiency.
Ksyvords: Pei^immon hvit, Thach That, citric acid, previous storage.
Ngiriri phan bien: PGS.TS. H o ^ g Thi 14 Bkig Ngdy nhan bai: 18/02/2019
Ng4y theng qua phan bi^n: 18/3/2019 Ng^y duyet dang: 25/3/2019
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 7/2019
