KHOA HOC CONG N G H |
l\IGHIEI\l CLIU CHE D d BAD GOI, BAO QUAIXI QUA HOIXIG THACH THAT SAU THU HOACH
Nguyin Thi H?nh\ Vfl Thi Nga^
TOMTAT
Muc dich ciia nghien cuu nay nhdm lua chon che do bao goi va bao quan qua hong Thach That (Diospyros AaA/Thunb.) sau thu hoach de tir do de xuat quy trinh bao quan ddi voi lo&i qua nay. Nguyfin lieu hdng sau ttiu hoach dupe xu ly so bo roi tien hanh bao quan d 3 nhiet do: 1"C, 4"C, TC (+ O.S^C), dp am 85-90% va theo doi su bien doi chat luong trong 28 ngay bao quan. Sau do danh gia kha nang tu chin ciia qua hong d dieu kien thirdng (25-30''C, 65-7596). Tren co sd lua chon duoc ch^ do nhiet do phii hop, da tien hanh lira chon vat lieu bao bi thich hop de bao goi qua hong. Bao bi dirpc lua chon trong nghien cmi nay la LDPE voi 2 do day 0,02 mm va 0,04 mm, co va khong co chat hap thu (KMnOj:C =1:1) so sanh vdi miu ddi chiing.
Ti^n hanh theo doi va danh gia cac chi tieu chat lugng trong 35 ngay bao quan. Ket qua cho thay ch^ dp bao quan thich hpp nhdt cho qua hong Thach That la bao gdi hong trong tiii LDPE kin, day 0,04 mm, c6 chdt hap thu KMnOj:C=l:l, ty le chat hap tiiu/khdi luong qua = 0.5%, nhiet dp 1 ± 0,5"C, dp am 85-90%, tiiol gian bao quan 35 ngay. Voi che do bao quan nay, hong vSn dam bao dupe chat luong dinh duong va cam quan cua qua.
Tii khda: Quahdng, Thach That, baogdi, baoguan, chit hap thu, sau thu hoach.
1 . DAT VAN BE
Qua hong TTiaeh That {Biospyros kaklThndb) la mgt trong nhiing loai qua quan trpng dupe trong nhieu nhdt Id d" cdc tinh phia Bae. Qua hong cd dac diem vo qua mong, thit qua mem, rat gidu dinh dtrong nfin dfi bi hu hong nfiu khdng dupe bao quan kip thoi. Ngay nay khoa hpc tren the gidi cdng nhu a Vifit Nam da chi ra rdt nhieu phuong phdp de keo dai thdi gian sir dung eho loai qua nay.
Nhieu nghifin ciiu da chi ra khi bdo quan qua hdng a nhifit do thap khong xay ra hifin tuang ton thuong lanh va duy tri dupe chat luang cua qua [4, 8]. Qua hong 0iospyros kakih.) Anqchm ti-u6'l''C, S^C va 15''C (dp am 85-90%) vd dupe ddnh gid sau 13, 20,27 vd 34 ngay de theo ddi chat lupng qua thay doi trong sudt qua trinh bao quan. Ket qua cho thay qua duge luu trii d" l^C duy tri dugc chat lugng tot nhdt so vdi 2 chfi do eon lai [8].
Mang LDPE eo tac dung lam cham qua trinh mem hoa va tic chfi nhiing rdi loan d' vo vd thit qua, la nhung yeu to han ehe khi bao quan eua qua hong thdng thirdng. Thai gian ton trir cua giong hdng Nhat Ban khdng chat 'Fuyu' (Diospyros kaki L.) trong a
' Vien Cong nghe Sinh hpc va Cong nghe Thirc pham, Trudng Dai hgc Bach khoa Ha Noi
^ Vien Co dien nong nghiep va Cong nghe sau thu hoach Email: [email protected]
Isarel, dupe keo dai tii 6 Ifin 18 tuan b O'C nhd bao goi bang mang LDPE bao quan a che do dieu bifin khi MAP [7]. Rutii Ben-Arie va cs. (1992) da su dung cac tiii LDPE cd do day khdc nhau: 2, 4 va 7 pm de bao goi hai gidng hong Hachia va Triumph. Ket qua thay rdng mang LDPE day nhat (7 pm) phii hgp cho bao gdi qua hong Hachia va Triumph khi bao quan dai trong difiu kifin lanh va sau dd ton trir a nhifit do thudng [3. 5].
Muc dich cua vific su dung chat hap thu ethylene Id Iam giam nong dp ethylene xung quanh qua, han che qua trinh chin va mfim hda qua, tir do keo ddi ban sii dung qua. Chat hap thu dupe dung phd bien la potassium permanganate (KMnO^) cung vdi mpt chdt mang tra co be mat Idn nhu silicagel, nhdm oxit va cacbon boat tinh [6, 9]. Nguyfin ly ea ban ciia phuong phap nay la KMn04 se oxy hoa ethylene thdnh MnO^va COj. Tii do keo ddi thdi gian bao quan ciia qua hdng.
Trong pham vi nghien ciiu nay da tim hieu anh huong cua nhifit dp den mpt sd chi tifiu chdt lugng ciia qua hong Thach Thdt (Diospyros kaklThnrib).
Sau khi lua chpn duoc nhiet dp phu hop, tien hdnh lua chpn che dp bao goi phii hpp cho qua hong, tu do dua ra quy trinh bao quan thich hgp ddi voi loai qua nay.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019
KHOA HOC CONG NGHE
2 . niGUYBU UEU VA PHUONG PHAP N G U E N C U U 2.1. Nguyfin li$u nghifin ciiu
Nguyfin lieu qua hong (Biospyros Aa^Thunb.^
thuoc gidng hong Thach Thdt dupe ti-Png va tiiu hoach tai huyen Tan Yen, Bdc Giang. Qud hong dupe Idy mdu vao chinh vu thu hoach thang 10 nam 2017 va 2018, CO dp tudi 100 -110 ngay ke tir khi dau qua.
Hong duac thu hai nhe nhang vao buoi sang trong dieu kifin kho rao. Dung keo cdt each cuong khoang 1 cm, bd la. Xfip qua vao ti-ong thtmg xdp due 16 va van chuyen ve phdng thi nghifim. Qua dupe bd tri thi nghiem trong ngdy.
2.2. Phuong phdp nghifin ciiu 2.2.1. Phuongphap bd tii thi nghiem a. Xac dinh inh budng cua nbiit dp din chat lupng cua qui hdng trong thdigian bio quin
Nguyfin hfiu hong sau thu hoach dugc dinh lugng 3 kg/mdu, tien hanh xii ly bdng dung dich axit citnc pH 3-3,5, nhifit dp SO^C trong 10 phiit. Cdc mdu sau khi xu ly duoe de rao nude, bao gdi trong tiii PE due 16, bao quan 6 cdc nhifit dp khdc nhau. Cac cdng thiic thi nhifim gdm: TN5.1, TN5.2, TN5.3 ling vdi nhifit dp bao quan a l^C, 4''C, TZ (+ 0,5<'C), do dm 85 - 90%. Thi nghifim dupe bd tri hoan toan ngau nhien, mdi cdng thiic lap lai 3 Idn va d* eiing mot thdi diem.
Theo ddi va lay mdu phan tich chat lupng trong 28 ngay, tan sudt 7 ngdy/ldn. Sau 28 ngdy bao quan lanh, ddnh gia kha nang ty chin eiia qua hdng d difiu kifin thudng (25-30''C, dd am 65-75%). Phan tich chat lugng ede mdu b thoi diem qud chin hodn toan. Cdc ehi tieu chat lupng duge danh gid gdm: Dp ciing, hao hut khdi lugng, sir thay ddi mau sac, ham lupng chat kho hoa tan tong sd (TSS), ham luong duong tong sd, ham lugng axit hiiu co tong sd, ham lupng tanin va chat luong cam quan cua qua.
b. Nghien cuu lua ebon che dp bao gdi phii hpp Nguyfin lifiu hong sau thu hoach dugc dinh lupng 3 kg/mdu, tien hanh xii ly bang dung dich axit citric pH 3-3,5, nhifit dp SO^C ti-ong 10 phut. Thi nghifim dugc bo tri hoan todn ngdu nhifin, mdi cdng thiic lap lai 3 lan vd 6- cung mgt thoi diem. Cac mdu sau khi xu ly dugc de khd ttr nhifin, bao goi trong cac vat lifiu khae nhau vd bao quan b nhifit do z"C (+
0,5''C). Cac cong thiic thi nghifim gom: TN7.0:
Khong bao goi, khdng co chat hap thu; TN7.1: Bao bi LDPE ddy 0,02 mm, cd chat hap thu (^MnO^.C -1:1);
TN7.2: Bao bi LDPE ddy 0,02 mm, khong cd chat hdp
thu; TN7.3: Bao bi LDPE ddy 0,04 nun, cd chdt h ^ tiiu (KMn04:C =1:1); TN7.4: Bao bi LDPE day 0,04 mm, khdng cd chat hap thu. Ty lfi chdt hdp tfau/khdi luong qua = 0,5%. Tlieo ddi va Idy mdu phan tieh chat lugng trong 35 ngay, tdn sudt 7 ngdy/ldn. Cdc chi tifiu chat luong dugc danh gid gdm: Dp eiing; hao hut khdi lugng; sir thay doi man sde; TSS; ham lupng dudng tdng s6; ham lirang axit hiiu ea tdng sd; ham luang tanin vd chat lupng cam quan eiia qua.
2.2.2. Phuong phip pban tich chat lupng Phuong phdp lay mdu qua ttroi theo TCVN 5120 - 90.
Su bien doi mdu sdc vo qua dupe do bang may do mau Minolta CR-300 cua Nhat
Ddnh gid chdt lugng cam quan bdng phuong phap cam quan md ta.
Xac dinh ham lugng TSS ("Bx): Sii dung khuc xa ke Atago Model PAL-c (Code 3840). Hang san joiat Atato, Nhat. Thang do: 0 - 81%.
Xdc dinh ham lupng axit tong so (%) theo TCVN 5483 -1991 (tinh tiieo axit make).
Xdc dinh ham lupng tanin bdng phucmg phap Kahpemanganat (%).
Xdc dinh ham lugng dirdng tdng sd flieo phuong phdp Graxianop (%)
Xdc dinh do ciing bdng mdy do dp ciing FT 327 (Itaha). Su dung ddu do 8 mm, don vi kg/cm^.
2.2.3. Phuong phap xu ly sd hiu
Ket qua thi nghifim dupe phan tich ANOVA va kiem dmh LSD (5%) bdng phdn mfim thdng kfi SAS 610.
3. KFT QUA VA THAO LUAN
3.1. Anh huong ciia nhifit dO d€n chdt lupng ciia qua hdng theo thdi gian hao quan
3.1.1. Anh hudng cua nhiet dp din su bien ddi do cung, bao hut khdi lupng, mau sic va cam quan ctia qui bdng
Nhifit dp bao quan la yfiu td quan trpng nhat anh huang dfin chat luang va thdi gian bao qudn rau qua noi chung va qua hdng ndi rifing. Anh hirong eiia nhiet dp bao quan dfi'n sy bien doi dp ciing, hao hut khdi lupng va su thay doi mdu sac AE'^ dupe tiie hifin trong hinh 1.
Nhm chung, nhifit do bao qudn co anh hircmg Idn den su bien ddi dp ciing qua. Mdu hdng ban dau NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019
KHOA HOC CONG NGHE CO do Cling 3,9 kg/cm^, sau d6 giam ddn theo thdi
gian bao quan vdi miie dp gidm khdc nhau phu thuoc vao nhifit do. 6 nhifit dd VC (TNS.l) duy ti-i tdt nhat dp Cling qua, tifip tiieo la mdu 4°C CrN5.2). Sau 28 ngdy bdo quan, dp ciing qua b l^'C vd 4PC lan lupt la 3,6 kg/cw? va 3,1 kg/cm^. O nhifit dp 7°C, dp ciing qua giam nhanh xuong 1,4 kg/em^ b ngay bao quan cuoi cimg.
Sy giam do ciing trong qua trinh bao quan la do hoat dpng ciia cdc enzyme phan huy pectin b thdnh
te bao thanh pectin hda tan, lam mfim qua theo thai gian bao quan. Hoat dpng ctia cac enzyme nay phu thuoc vao dieu kifin nhifit do bao quan, nhiet dp cang thap thi tdc dd phan ling thuy phan do enzyme cang thdp va ngugc lai. Do do, nhifit do bao quan thdp cd tac dung duy tri dp ciing qua tdt hon. Trong nghifin ciiu anh huong cua nhifit do den chat lugng gidng hong "Rojo brillante", L Amal va cs. (2004) [8] eiing chi ra qua luu trii b l^C eho do ciing eao nhat so voi S^CvalS^C.
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Hinh 1. Anh hudrng cua nhifit dd dfin su b i ^ ddi dd ciing, hao hut khdi lugng vd mau sac qua hdng theo tiidi gian bao quan
Ngupc lai vdi sy bien doi do ciing, sy hao hut khoi Itrong qua tang ddn theo thoi gian bao quan va miic do tang ty lfi thuan vdi su tang nhiet do. Hai mdu TN5.1 va TN5.2 eo hao hut khdi lupng thdp nhat Hao hut khoi lupng cua mdu TN5.3 cao hon han hai mdu con lai, sau 28 ngay bao quan hao hut khdi lupng mdu TN5.3 la 1,6%, cao gap 1,58% mdu TN5.2 va gap 1,68%
mdu TNS.l. Su hao hut khdi lugng cua rau qua la do qua trinh bay hoi nuoc va ton hao cac chat hiiu ca tham gia vao qua trinh hd hap [1, 2]. Nhifit dp bao qudn cang tiiap cang Iam giam cuong do hd hap cua
qua, do do han chfi ton tiiat ve khdi lugng.
Su thay ddi mau sac cua cac mdu ihi nghifim the hifin qua chi so AE'^t, dieu nay hoan todn phu hpp vdi ket qud ddnh gia cam quan mau sdc qua d bang 1.
Mdu TN5.3 c6 sy bien doi AE'^t nhieu nhat, qua hong chuyfin sang mdu cam do d' ngay cudi bao quan (AE\b=25,92). Mdu TN5.2 c6 miic bien ddi mdu cham hon, vdi mdu cam dam cua qua a ngay cudi (AE'ab-12,12). Mdu TNS.l duy tii chat lupng mau sac qua tot nhat, mdu qua chuyen tu vdng hoi xanh ban dau sang vang sang d ngay cudi, voi AE\b= 8,31.
Bang 1 Anh huaner cila nhifit dO dfin chat luong cam quan cua qua hong theo thdl gian bao quan Thdigian
(ngay) 0
28
Mdu thi nghifim TN5-1 (l^C) 1 TNS-2 (4«C) - Num vang xanh tuoi, qua mau vang hm xanh, ciing va gion - Vi rat chat
- Mau vdng sang, qua cting gidn, ttroi.
- Vl rat chat, chua cam nhan dugc vi ngpt.
- Khdng ed bieu hien ton tiiuong lanh.
- Mau cam hoi dam, qua ciing, gion, tuoi.
- Vi chat, ehua cam nhan duoc VI ngpt.
- Khdng CO bieu hien t6n thuong lanh.
TN&-3 (7<'C)
- Mdu cam hoi dd, qua hoi mfim, tuoi.
- Vi chat, hoi nggt.
- Khong CO bieu hifin tdn tiiuong lanh.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019
KHOA HOC CONG N G H l
Su bien doi chat luong cam quan qua 6 ngdy bao quan cudi so vdi ngay ban ddu dtrgc the hifin ro b bang 1, O ea 3 nhiet dp bao quan, khong cd bieu hifin ton thirong lanh dfin ngdy bao quan eudi. Mau TNS.l cho hieu qua duy tri chat lupng cam quan tong the tot nhat, tiep theo la mdu TN5.2 vd cudi cimg la mdu TN5.3.
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3.1.2. Anh buong cua nhiet dp den mdt so cbi tieu boa ly cua qua bong
Nhiet dp bdo quan co anh huong manh me den sy bien ddi mpt sd ehi tifiu hda ly cua hong nhu ham lupng TSS, duang tdng so, axit huu ea va tanin. Dd thi minh hpa sy bifin doi eae chi tifiu chat luong nay duge the hifin trong hinh 2.
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Hinh 2. Anh huong eua nhifit do tkn sy bi6i doi mpt sd chi tifiu hda Iy cua qua hong theo tiidi gian bao quan va TX5 3. O ngay bdo quan thii 28, ham lugng axit Ket qua phan tieh cho thay theo thoi gian bao
quan, hdm lugng TSS, ham lugmg axit hiru ca vd ham lugng tanin cua cae mdu dfiu cd xu hirdng giam lien tuc, dong thdi ham lupng dudng tdng sd tang ddn theo thai gian bao quan.
Ham lugng TSS giam dan tii 22,l*Sx xuPng con 20,rBx CTNS.l); 18,/Bx CrN5.2) va 16,9^x CTNS.S) b ngdy bao quan thii 28. Ket qud nay phu hgp vcri nghifin ciiu cua L Amal va cs. (2004) khi nghifin ciiu ve sy bien ddi hdm lugng TSS cua gidng hdng "Rojo brillante" ti-ong tiidi gian bao quan [10]. Su giam ham lupng TSS la do cac chat htru ca da tham gia vao qua trinh ho hap ciia qua ddn den chi sd nay giam trong 28 ngay bao quan.
Mdu hdng a TNS.l deu cho miic giam ham lugng axit hiiu ea va tanin Ihap ban hdn so vdi TN5.2
hiiu ca cua hong a TNS.l. TN5.2, TN5.3 Idn lupt la 0,23%, 0,17%, 0,15% va ham lupng tanin Idn lupt la 15,40%, S,33% va 1,12%. Nguyen nhan do axit htm co la nguyfin hfiu trong qua trinh hd hdp cua qua va 6 nhiet dp thdp cd tdc dung kim ham qud trinh ho hap, do do lirong axit hiru eo tong sd mat di ciia qua hdng bao quan d nhifit dp cao se Idn hon. Ddi vdi su bien ddi ham lupng tanin, d- nhifit dp thdp da lam chdm qua trinh chin ciia qua do dd chi sd nay eung cd tiX.
dp giam cham ban va mdu TNS.l la cham nhdt Xet ve dnh huang ciia nhifit dp den ham lupng duang tong sd, hong a TNS.3 co sy tang ham lirpng duong cao nhdt (14,04%), sau dd la TN5.2 va TNS.l, vdi ham lugng duong tong sd or ngay bao quan eu^
lan lupt la 13,98% va 13,21%. Hdng la loai qua ed hd hdp dot bifin nfin trong qua trinh bao quan co su bi^n
90 N O N G NGHIEP V A PHAT TRIEN N O N G THON - KY 1 - THANG 5/2019
KHOA HOC CONG NGHl doi tinh bot tiianh duong. 6 nhifit dd tiiap eo tdc
dung ldm cham qua trinh chin ciia qua nen lugng dudng t^o Ihanh ciia mdu bdo quan d- l^C la thdp nhat vd mdu 7°C la Ion nhat
Tdc do cdc phan iing sinh ly, smh hda difin ra trong nong san ty lfi thuan vdi nhiet do bao quan. Do do, hong b nhiet do thap 1*'C CTNS.l) cd su bien ddi cae chi tifiu chat lupng so vdi thoi diem ban ddu (tiiroe bao quan) thap nhat, tifip theo la TN5.2 (4''C) vaTN5.3 (TQ.
Nhu vay, nhifit dp l^C duy tri chdt luong tong the eua qua hdng tdt hon so vdi 4°C va TQ. sau 28
3.1.3. Anh budng cua nhiet dd den khi nang tu chin cua qua bong sau bio quin
Nhifit dp thdp co tdc dung keo ddi thdi gian ton trii ciia qua tuoi. Tuy nhifin, nfiu nhifit dp thdp duoi nguong chiu dung cua qua se gay tdn thirong lanh vd anh hirdng den chat luong ciia qua sau bdo quan. Do do, nhifit dp bao quan lanh tdi uu cho hong phai ddp ling dugc cd 2 yfiu cdu: duy tri tdi da chat lirong tong the qua trong sudt thoi gian bao quan lanh, ddng thdi khdng lam anh hirong d^n qua trinh chin cua qua. Vi vay, da danh gid kha nang chin cua cac mdu hdng sau khi bao quan lanh qua chat lupng qua sau khi d^ chin hr nhifin d di^u kifin tiiudng (2S-30''C, do am 65-75%).
ngay bao quan.
Bang 2. Anh hucmg cua nhifit dp d^n chdt lugng chin ciia cdc mdu hdng sau hao quan
1. Thoi gian chin 2. Do cimg (kg/cm^
3. Mau sac (L,a,b)
L*
a*
b*
4. TSS (°Bx)
5. HL axit hiiu co (%) TS (%) 6.DuangTS(%) 7. HL tannin (%) 8. Cam quan
Mau thi nghifem TNS.l (1°C)
5-7 ngay
<0,5 35,24 + 0,83 21,38 ±0,70 16,80 ±0,46 14,6 ±0.5 0,15 ±0.01 14,36 ±0,10 0,24 ±0,08
TN5.2 (4''C) 5-7 ngay
<0,5 34,94 ± 0,50 20,65 ±1,91 17,12±0,74 15,0 ±0,1 0,13 ±0,02 14,38 ±0,05 0,30 ±0,03 - Qua chin mau do tiroi.
- Qua m^m, cang bong, dfe tach vo va num qua, - VI r^t ngot, thom, khong ch^t.
TN5.3 (J'Q 4-5 ngay
<0,5 34,77 ± 0,29 21,43 ±1,02 16,80 ±0,91 14,6 ±0,3 0,12 ±0,01 14,61 ±0,13 0,22 ±0,06
vi rat ngpt va thom.
a) Mau qua sau 28 ngay bao quan lanh b) Mau qua sau 28 ngay bao quan lanh va d^ chin o dieu kien ttr nhifin
Hinh 3. MSu hdng sau bao quan 1 ^ va khi q u i chin & 4 i & kien tii nhi6n
Ket qua phin tich a bang 2 va hinh 3 cho thay: chin va chat lucmg cua qua hong. 6 ca 3 miu, sau khi nhiet do bao quan lanh khong lam anh huong de'n do bao quan lanh de o dieu kito tu nhita, qua chin
NONG NGHliP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019 91
KHOA HOC CONG N G H £
trong thoi gian 4 - 7 ngay va co chat luong tdt, cu the la: qua chin mau do tuoi, mem, cang bdng, dfi bdc tach vd va num qua, vi rdt nggt vd thom.
Tom lai, tdng hop cac kfit qua ddnh gid anh hucmg eua nhifit do bao quan den chdt lugng tong the, kha nang tu chin sau bao quan va cuong do hd hap cua hdng cho thdy nhifit do l^C (±0,5''C) co kha nang duy tii chat luong bao quan tdt nhat cho qud hdng ma khong lam anh huong den dp chin va chat lugng sau bao quan, sau do lan luot Id 4''C vd 7''C.
3.2. Nghifin cutu lua chpn ch^ dp bao goi phii hpp cho qua hdng
De nghien cuu lua chgn ch^ do bao gdi phii hgp cho bao quan hong trong dieu kifin lanh l+O.S^C, da su dung 2 loai vat Hfiu LDPE ddy 0,02 mm va 0,04 mm, CO vd khdng c6 chdt hap thu KMn04:C=l:l.
3.2.1. Anh hudng cia che dp bao gdi den su bien ddi dp cung, bao hut kbdi luang, miu sac va eim quan cua quahdng
Anh huang ciia che do bao goi den sir bien ddi dg ctmg, su hao hut khdi lugng vd su thay ddi mdu sdc AE*ab dupe thfi hifin trong hinh 4.
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Bo ciing la thiroc do quan trong danh gia chS luong qua h-ong qua trinh bao quan. MSu TN7.0 ai do ciing tang ddng ke trong qua trinh bao quan, do tac dung cua bao quan lanh, dong thiri do khong c6 bao bi nen qua bi m^t nuoc. dai hon va do do lam tang chi so dp cung qua. Cac mlu thi nghiem con l^i Stu duy tri do Cling t6t trong 14 ngay (TN7.2, TN7.4) va trong 28 ngay (TN7.1, TN7.3) nho anh huong cua bao quan lanh. Den ngay cuoi bao quiin, mlu TN7,3 vln duy tri duoc do ciing cao nhat (3,8 kg/cm^, sau do la TN7.1 (3,5 kg/cm^ do tac dijng cua chft hap thu ethylene. Hong (yTN7.2 va TN7.4 co do ciing qua thap hon ( 3 , 0 - 3 , l k g / c m ^ .
V6 hao hut khdi luong ttr nhien, mlu TN7.0 c6 hao hut khdi luong tang lien tuc ddn 3,4% ii ngay bao quan cudi do su bay hoi nuoc ciia qua xiiy ra miiiih me khi khdng co bao bi bao vd. O cac mlu thi nghidm cdn iai, hao hut khdi lirong cd xu hudng tang nhe iheo thdi gian bao quan, cho thay ro ret tac dung ciia bao bi bao quan den tdn that khdi luong qua.
Mau TN7.3 cd hao hut khdi luong d ngay cudi thap nhat (0,89%), sau dd IaTN7.1 (1,13%),TN7.2 (1,75«) vaTN7.4(l,26%).
Do khac biet aiins do mau it
1 14 n 23 15
Hinh 4. Anh hudng cua ch^ dp bao gdi ddn su bidn theo thdi Str bien doi man s i c ciia cac m l u thi nghiem duoc danh gia qua cam quan (Bang 3) va gia tri AE*,j (Hinh 4). Vd co ban den ngay bao quan thir 28, cac m l u thi nghiem TN7.1, TN7.2, TN7.3 va TN7.4 vin duy tri mau s i c tdt (mau vang sang), cdn m l u ddi chiing TN7.0 da chuyen sang mau cam hm dam, hod xin. Tuy nhidn, den ngay 35, miu TN7.2 va TN7.4 b i t dau chuyen sang mau cam hoi dam, m i u 7.1 va 7.3 vin cd mau vang, cdn mau TN7.0 cd mau cam dam, xin do mat nude. Cu thd gia tri AE'.b cua cac m i u d ngay bao quan thir 35 la
ddi do Cling, hao hl;lt khdi lupng v l mlu sic qua hdng a bao quan
15,09 (TN7.0), 5,69 (TN7.1), 10,55 (TN7.2), 4,77 (TN7.3) va 9,49 (TN7.4).
Su bidn ddi chat lupng cam quan qua d ngay bao quan cudi so vdi ngay diu dupe thd hidn ro d bang 3.
6 tat ca cac thi nghidm deu khdng cd bidn hidn t^n thuwng lanh den ngay bao quan cudi. Cimg vdi sil mat nude va tang do ciing, m i u ddi chiing TN7.0 c6 chat liKmg cam quan kem: qua bi heo, nhan do mt nude, man cam dam xin, vi chat. Miu TN 7.1 va TN7.3 duy tri chat lupng cam quan tdt nhat, Hdp theo laTN7.2vaTN7.4.
92 NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 1 - THANG .S/snil
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Bing 3. Anh huftng ciia ch^ dd bao gdi ddn si; bidn doi chit lugng cam quan dia qua hdng Thdigian
(ngiy)
T
Mdu thi nghifim TN7.1
- Niim vang xanh tuoi, qua mdu vdng hoi xanh, cung vd gion - Vi rat chat
TN7.3 TN7.4
Mau qua vang cam ddm, xin.
Qud heo, nhan.
Vl chat Khong ton thirong lanh.
Mau qua vang tuoi. Qua Cling, gidn. Vi chat.
Khong tdn thuong lanh.
Mdu qua cam hoi dam, tuoi.
Qua Cling, gion.
Vi chat. Khong tdn thuong lanh.
Man qua vdng tuod. Qua rat Cling, gion. Vi chat. Khdng ton
thirong lanh.
Mau qua cam hoi dam, tuoi.
Qua Cling, gion.
Vi chat Khdng ton thuong lanh.
3.2.2. Anh budng eua cbi dd bao gdi din mdt sd' cbi tieu chat lupng hda ly cua qua bong
Anh hirong cua che dp bao gdi den sir bifin d6i mpt sd chi tifiu chat lugng hoa ly khdc cua hong nhu ham luong TSS, hdm lugng duong tdng sd, ham lugng axit hiiu ca, hdm lugng tanin dugc th^ hifin trong hinh 5.
Ke't qua phan tich cho thay theo thoi gian bao quan, ham lugng TSS, ham lugng axit hiru co vd ham luong tanin cua cac mdu deu co xu huong giam lien tuc, ddng thoi hdm lupng duong tdng s6 tang lifin tuc.
oBtiii 22 5 , 22 •
ns 1
20 5 ' 20 - 19 S
19 • 18.S
18 - 17 5
•
% ^"-^ r n r -
0.26 ' ^ 0.22 - —
0 2 0 1 8 - - - O l f i
0 1 2
0
TSS
^ • ^ ^
7 I d 21 2U Ngav
HLaxithu'uco'
7 14 21 28 NgiV
$
3S
-
3S - • - T N 7 0 H i - T N 7 1 - * - T N 7 2 TN7 3 - f - T N 7 4
- • - T N 7 0 - • - T N 7 1 - * - T N 7 . 2 TN7 3
Ham lupng TSS ciia mdu hong TN7.0, TN7.2 va TN7.4 gidm nhieu b ngay bao quan thii 35, gia tri nay ndm trong khoang 19,2 - IQ.S^Bx (khdng cd sir khdc biet dang k^ giua cdc mdu). Mdu TN7.3 duy hri TSS tdt nhat (20,7''Bx), hfip theo laTN7.1 (20,0'^Bx).
Xet ve sir thay ddi cua ham lupng duong tdng, mdu TN7.0 tang cao nhat do mat nuoc trong qua trinh bao quan. Mdu TN7.1 va TN7.3 cd su tang nhe, khoang 13,13 -13,26% nhd tdc dung cua chat hap thu ethylen da han che dupe anh hirong cita ethylen npi sinh tu nhifin trong qua den su bifin ddi sinh ly, sinh hda, nhd' do, han che dugc bien doi cdc chi tifiu chat lupng qua hdng.
Hinh 5. Anh hu6ng cua ch^ dO bao gdi d^n si? bi^n ddi mOt sd chi tifiu chdt lugng hda ly cua qua hong theo thdi gian bao quan
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019 93
KHOA HOC CdNO N G H £
Ham lupng axit hiiu ca cua cac mdu cd xu hudng giam nhe theo thoi gian bao qudn. Khong co sir khdc bifit ddng ke giua cac mdu.
Ham lugng tanin cua TN7.0 (ddi chung) gidm nhieu nhdt, ngay cudi bao quan cdn khoang 9,55%. O ngay bao quan cudi, TN7.3 va TN7.1 cd ham lugng tanin cao han ban so vdi cdc mdu con lai, lan lupt la 15,66% va 15,22%, tiep theo la TN7.4 (13,45%) va TN7.2 (12,25%). Do hdm lupng tanin con rat cao nfin cdc qua vdn con rdt chat b ngay cuoi bao quan.
Tom lai, qua tdng hop cdc ddnh gid ket qua nghifin cuu ve sir bien ddi chat lupng ciia qua hong b cac che dp bao goi khdc nhau, mdu TN7.3 cho ket qua duy tri chat lugng tdng the tdt nhat, nfin chpn bao bi bao gdi hong la LDPE ddy 0,04mm, cd chdt hdp thu KMnO^: C=l:l.
3.3. Dfi xudt qui tiinh xii ly, bao goi vd hao quan qua hdng sau diu hoach
Tdng hpp cac ket qua nghifin ciiu cua cac muc 3.1 va 3.2, da de xudt qui trinh xu ly, bao goi vd bao quan qua hong sau thu hoach nhu sau:
Qua hong sau thu hoach —*Lua chpn, phan loai
—*Ngam, rua —•Nhiing dung dich axit citric —*D^
rao—^ao goi ^ © a o quan lanh.
Thuyet minh qui trinh:
• Hong dupe thu hai d dp chin khi num qua vang xanh tuoi, mdu qua vdng (>80%) va cd mdu vang hai xanh d' dudi qua (<20%). Qua ciing gidn. Vi rat chat, chira nggt. Miii chua ro. Sau thu hai hdng dupe lua chgn, phdn loai, loai bd nhiing qua hong bi hong, bam dap, sau bfinh,...
• Tifin hanh nhiing hong trong dung dich axit citric pH 3,0 - 3,5; a SO^C trong 10 phut. Sau dd vat ra, de kho tir nhifin d dieu kien phong.
• Ddng gdi hdng trong tui LDPE kin day 0,04 mm, c6 chat hap thu KMn04:C-l:l. Ty lfi chdt hap thu/khdi lugng lugng qua = 0,5%.
• Bao quan hong trong kho lanh 1 ± 0,5°C, do am 85-90%. Voi chfi do bao quan ndy, hong cd th^ bao quan duoc tdi thieu 35 ngdy ma vdn dam bao dugc chat lugng cam quan vd tinh chat hoa ly ciia qua.
4.KEriUAN
Qua hdng Thach That khi bdo quan a nhiet do thdp da duy tri dugc chdt lugng ma khong thdy hifin tirgng ton thuong lanh trong sudt thdi gian bao qudn.
Kfit qud nghifin ciiu da cho thdy che dp bao qudn thich hpp nhat la bao gdi hong trong tui LDPE kin, dp day ctia tui 0,04 mm, ty lfi chat hap thu KMn04:C=l:l/khdi luang lugng qua = 0.5%, nhifit dq kho lanh la 1 ± 0,5°C, do am 8&-90%, thdi gian bao quan 35 ngay.
TAI UEU THAM KHAO
1. Ha Van Thuyet, Cao Hodng Lan, Nguyfin Thi Hanh (2015). Cong nghd bio quin che bien rau qui Nhd xudt ban Bach khoa Ha Ngi, Ha Ngi.
2. Qudch Dinh, Nguyfin Van Tifip, Nguyfin Van Thoa (1996). Cdng nghi sau tiiu boacb vi ehibiSn rau qua. Dai hpc Cong nghifip thanh pho H6 Chi Minh.
3. Dorria, M.Ahmed,-Ami R. M.Yousef and S.
M. A. Sarrwy (2011). Modiffed Atmosphere Packaging for Maintaining Quahty and Shelf Uk Extension of Persimmon Fruits. Asian Joumal of Agriculhiral Sciences 3(4): 308-316.
4. Elif Candir, Ahmet Erhan 0'zdemir, Mustafa Kaplankiran, Turan Hakan Demirkeser and Ercao Yildiz (2010). Storage hfe of non-astringent persunmons grown in the eastern Mediterranean New Zealand Joumal of Crop and Horticultural Science Vol. 38, No. 1, March, 1-6.
5. Hae Jm Kim, Duck Soon An, Gwang-Hwan Ahn and Dong Sun Lee (2011). Effects of him and seal conditions on the package atmosphere and storage stabihty of'Fuyu'sweet persimmons. Joumal of Food. Agriculture & Envuonment Vol.9 (1): 9^98.
6. Raija Ahvenainen (2003). Novel food packaging techniques. Woodhead Pubhshing in Food Science and Technology.
7. Ruth Ben-Arie and Yohanan Zutkhi (1992).
Extending the Storage Ufe of Fuyu' Persimmon by Modiffed-atmospbere Packaging. Hortscience 27(7):811-813.
8. Shiesh ChingChang; Liu HsiuLmg; Un HueyLing (2000). Studies on the possibk mechanism of ripening process induced deastringency in 'Syb Jou' persimmon (Biospyros kakiL.) ffuit Joumal of the Chinese Society for Horticultural Science. Vol. 46 No. 4 pp. 399-416.
9. Zagory D., Etiiylene - removing packaging, Active food packaging, pp. 38-54 (1995). Spinger.
Boston, MA
94 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/201S
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10. L. Amal and M. A del Rio (2004). Quahty of different temperatures Spanish Joumal pershnmon ffuit cv. Rojo brillante during storage at Agricultural Research 2 (2), 243-247.
RESEARCH OF PACKAGING AND STORING MODES OFTBE THACH THAT PERSIMMONS POSTHARVEST
Nguyen Thi HanhS Vu Thi Nga^
^Institute of Biology and Food Technology, School of Hanoi University of Science and Technology
^Institute for Agricultural Engmeering and Post Harvest Technology Summary
The purpose of this study was to select the packaging and storaging mode of Thach That persimmons (Diospyros kaki Thunb.) postharvest to propose preservation process for this fruit. The postharvest persimmons material were pretreated and stored at three temperatures: 1"C; 4"C; TC (± CS^C), 85-90%
humidity and monitored of quality changes during 28 days of storage. Then we assessed the ability of self- ripening of persimmons at normal conditions (25-30''C, 65-75%). Based on the appropnately selected temperature mode, we proceed to select fhe appropriate packaging material to pack the persimmons. The selected packaging in this study was LDPE with two thicknesses of 0.02 mm and 0.04 mm, with and without adsorbents (KMn04:C=l:l) compared to the control. We conducted monitonng and evaluation of quality indicators in 35 days of preservation. The results showed that the most suitable storing mode for Thach That persimmons was that persimmons was packaged in sealed LDPE bag, 0.04 mm thick, with absorbent KMn04:C=l:l, absorbent/fruit mass ratio = 0.5%, temperature 1 ± O-S^C, humidity 85-90%, preservation time 35 days. With this preservation mode, the persimmons ensured the nutritional and sensory quality of the fmits.
Keywords: Persimmon hnit, Thach That, packaging, preservation, absorbent, postharvesting.
Ngu6i phdn bifin: PGS.TS. D6 Van Chuang Ngdy nhdn bdi: 15/02/2019
Ngdy thdng qua phan bifin: 15/3/2019 Ngdy duyet dSng: 22/3/2019
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 5/2019