OANH GIA HIEU QUA BAO QUAN CAM HAM YEN CUA CH^
PHAM TAO MANG POLYETHYLENE - CANDELILLA
Phgm Cao Thang\ e|lng Thj Thanh Quyen^ Nguyin Duy LSm^
Trung tam Nghien CIFU va Kiem tra chat lu-ong ndng sin thirc pham Bg mdn Nghien cu'u Cdng ngh^ va Thiet bj bao quan ndng san thirc pham
Vi^n Co dien Ndng nghiep va Cdng nghe Sau thu ho^ch
Tom tat
MMC tieu cita nghien cuu ndy Id ddnh gid hieu qud cua chi phdm tgo mdng cd thdnh phdn chinh Id nhu tuang sdp polyethylene vd sdp candelilla trong bdo qudn qud cam Hdm Yen a dieu kien thudng trong thdi gian 7 tudn. De so sdnh, trong thi nghiem da sir dung them mdt chi phdm nhdp khdu BQE-15 ciia My. Kit qud thu dupc cho thdy chi phdm polyethylene-candelilla cho hieu qud bdo qudn khdng nhung tdt han nhieu so vdi ddi chimg md cdn tuang duang so vdi chi phdm BQE15.
Trong qud trinh bdo qudn, cudng do ho hdp, do chdc qud, mdu sde vd hdm lupng chdt rdn hda tan a hai cdng thiec phii mdng diu biin ddi it han vd chdm han so vdi ddi chimg. Sau 7 tudn bdo qudn, mirc tdn thdt khdi lupng tu nhien vd ty le thdi hdng a cdng thirc sie dung chi phdm polyethylene - candelilla thdp nhdt Id 8,6% so vdi ddi chung cao nhdt Id 29,9%. Qud cam d hai cdng thicc phii mdng vdn duy tri dupc chdt luang phu hpp vdi yeu cdu thuang mgi.
1.
DAT VAN Bt
Cam sdnh Ham Yen tft Idu da ndi tieng tham ngon vd trd thdnh ddc sdn cua huyen Hdm Yen tinh Tuyen Quang. Hien nay, dien tich trdng cam Hdm Yen da dugc md rdng ddng kl do dd cd nhu cdu ve bao quan nham gidm tdn that sau thu hoach cung nhu de chu ddng ngudn cung cdp qua tuoi cho thj trudmg. Bao qudn cam vd cdc loai qua cd miii khdc bang che phdm tgo mdng Id mpt phuang phap mdi dang dugc nghien cftu vd bat ddu dp dung d Viet Nam. Nguyen tde cua phuang phap nay Id tao ra mdt djch Idng dgng nhu tuomg de phii len be mat qud vd nhd cd tinh chdt dieu chinh khi vd hai nudc cfta mdng ma qua dugc gift tuai Idu ban, gidm duge tdn thdt khdi lugng, ddm bao hinh thfte ben ngoai cung nhu chat lugng ben trong (Park, 2000).
Hien nay tren thl gidi da cd nhieu ket qua nghien cftu vd sdn phdm thuang mgi hda vl chl phdm tgo mang bdo qudn qua cd mui. Da sd cac che phdm ndy cd thanh phdn chinh Id sap polyethylene, nhua cdnh kiln dd (Paul vd Moulik, 2001). Mdt sd sdp tu nhien nhu camauba vd candelilla da dugc nghien cftu va chftng td cd tac dung bao qudn tdt cho nhieu loai qud vd dugc ua ehudng do tinh chdt tu nhien so vdi sdp polyethylene (Plotto va Baker, 2005). Tuy nhien, vi gid thdnh cua cdc logi sap tu nhien ndy cao horn rdt dang ke nen hdu nhu khdng dugc sft dung cho qud cd miii. Tdng quan cac nghien cftu qudc te cho thdy hien cdn rdt it kit qua cdng bd vl hieu qua cua cdc chat tgo mang cd thdnh phdn polyethylene kit hgp vdi sdp camauba hay sdp candelilla ddi vdi hoa qua ndi chung vd ca qua cd miii (Faber et al., 2003). Nghien cftu duy nhdt ciia Hagenmaier sft dung chl phdm polyethylene- cadelilla da eho thdy bon hgp composit nay cd hifu qud cao trong bdo quan qua cam gidng Valencia (Hagenmaier, 2000; Hagenmaier et al., 2002).
Myc tieu cua nghien cftu nay Id ddnh gid hieu qud bdo qudn qud cam Ham Yen bdng chl pham tgo mdng dgng vi nhu tuomg sap polyethlene-candelilla vd so sanh hieu qud bao qudn dd vdi chl phdm chuyen dung cho bdo qudn qud cd miii nhdp khdu ciia nudc ngoai.
II. VAT LIEU VA PHU'aNG PHAP 2.1. Nguyen vat lieu
Cam Ham Yen dugc thu hai tgi vudn rdi chd vl phdng thi nghiem trong vdng 1 ngdy.
Chgn nhung qua cd hinh thfte d?p, tuomg ddi ddng deu, khdng bi tdn thuong ca hpc, cat cudng sat nftm qua. Rfta bdng nudc may rdi xft Iy diet nam mdc bang dung dich chfta Thiabendazole (TBZ) d ndng dp 300 ppm va hnazalin d ndng dp 200 ppm cd nhiet dp 52°C hong thdi gian 150 giay.
Sau khi phdn thdnh cdc cdng thfte, tiln hdnh phft mdng bdng phuomg phdp xoa, mdi qua sft dung khodng 0,4 ml chl phdm. Qud dugc dl khd tu nhien, sau dd xip vao cac thung cdc tdng vd bdo qudn trong dilu kien nhiet do phdng (nhiet do 20-29°C, do dm KK 70-85%). Bd tri thi nghiem thdnh 3 cdng thfte, moi cdng thfte gdm 40 qud, lap lgi 3 Ian.
Sap polyethylene Id epolene EIO mua cfta Hang Westlake (My); sap candelilla do phong Nghien cftu Qua cd mui thudc Bd Ndng nghiep cung cdp, axit oleic va morpholin tuomg ftng la chat hogt ddng bl mat vd kiim amin dl lam chat nhu hda. Chl phdm tgo mang chuyen cho bao qudn qud cd mfti BQE-15 (nhdp khau tft Hoa Ky) do Bd mdn Nghien cftu Cdng nghe va Thiet bj bdo qudn ndng sdn thuc phdm - Vien Ca dien Ndng nghiep vd Cdng nghe Sau thu hogch cung cap. Cdc hda chat khdc dung cho phan tich chat lugng qua la nhimg hda chat cd do sgch P hodc PA.
2.2. Chuin bj c h l pham tao mang sap polyethylene-candelllla
Nhu tuomg sdp epolene va sap candelilla dugc chuan bi rieng re rdi trdn lgi vdi nhau. De pha chuan bj nhu tuomg sap epolene, can 50 g epolene EIO va 10 g axit oleic dun ndng chdy d nhiet do 130°C rdi nhd tft tft 9 g morpholin vdo hdn hgp. Khuay deu trong sudt qud trinh dun.
Sau dd rdt hon hgp tft tft vao 180 g nudc d 95-98°C dong thdi khuay dlu vd bd sung chdt chdng bpt. Lam ngudi nhanh den 40°C. De chudn bi nhu tuomg sdp candelilla, cdn 40 g sap candelilla va 8,0 g axit oleic. Nhiet dp dun ndng chay Id 95-100°C. Bd sung 8g morpholin va khudy deu. Rot tft tft 160 ml nudfc ndng vdo hdn hgp. Che pham composit sap polyethylene vdi sdp candelilla d dang nhu tuomg sau khi hodn thanh cd pH = 8 vd ndng dp chat tan 15% theo ty 1? hai logi sap bang nhau.
2.3. Phu'O'ng phap xae dinh ty le tdn thit khdi lu'O'ng tu* nhien wk ty le thdi hong qua
Ty 1? hao hut khdi lugng tu nhien dugc tinh theo cdng thfte: X (%) = [(Ml - M2): Ml] X 100, trong dd MI (g) la khdi lugng qua trudc bdo qudn va M2 (g) la khdi lugng qud d cdc lan phdn tich. Ty 1? thoi hdng qua dugc tinh theo cdng thfte: X (%>) = [M2: Ml] X 100, trong do Ml Id tdng sd qua theo ddi, M2 la tdng sd qud thdi hdng sau cac Ian kiem tra djnh ky.
2.4. Phu'O'ng phap xae djnh cac chi tieu co* ly va sinh ly
Biln ddi mau sac: Xdc djnh bang mdy do mau Minota (CR-300, Ramsey, NJ, My);
Do chac qua: Xdc dinh bdng may Fruit Pressure Tester (Bertuzzi, Italia);
Cudng do hd hdp: Do ndng do khi O2 vd CO2 trong cac mdu dugc xdc dinh bdng mdy do hd hdp (may ICA, Anh).
2.5. Phu'O'ng phap xae djnh cac chi tieu hoa hoc cua djch qua va chit lu'O'ng cam quan
Xdc djnh ham lugng chdt khd hda tan tdng sd theo TCVN 4 4 1 7 - 8 7 , ham lugng axit hChi ca tong sd theo TCVN 5483-91, ham lugng vitamin C theo TCVN 6427-2: j998 va danh gid chdt lugng cam quan theo TCVN 3215- 79 vdi qua bao quan sau 7 tudn.
2.6. Phu'O'ng phap xO ly sd lieu
Sft dimg Microsoft Excel va phdn mim IRISTAT 4.0.
III. K^T QUA VA T H A O L U A N
3.1. Tac dyng cua cac c h l pham tao mang t&\ mu'c ton thit khdi lu'O'ng ty nhien va ty le thdi hdng cua cam Ham Yen trong qua trinh bao quan
Kit qud d bdng 1 cho thdy ty le ton thdt khdi lupmg tu nhien (KLTN) cfta cam tdng ddn theo thdi gian bdo qudn. Cdng thfte ddi chftng (DCI) cd ty 1? tdn thdt Idn nhdt, sau 1 tudn da gidm 9,27%, sau 5 tudn la 24,6%) va sau 7 tuan ty 1? hao hut len tdi 29,87%. Trong khi dd d cdng thfte qud cd phft nhu tuomg sap polyethylene-candelilla (TN) ty le tdn thdt KLTN d cdc thai dilm 1, 5 vd 7 tuan tuomg ftng Id 1,79%, 6,67 va 8,57%. Cac mftc tdn thdt ndy Id nhd ban nhilu so vdi ddi chftng (DCI). So sanh hai cdng thfte phu mang thay khdng cd sir khdc nhau cd y nghia gifta hai cdng thfte phft mdng TN vd cdng thfte phft mang BQE-15 (DC2).
Ve ty 1? thdi hdng, cdng thfte DCI cd ty I? cao nhat tdi 45% sau 7 tuan bdo qudn vd bj hdng 5% ngay tft sau thft 2 tuan 5%. Trong khi dd d cac cdng thfte phu mang thi ty le thdi hdng it hon, hdng 15% sau 7 tudn bdo qudn d cdng thfte DC2 vd chi hdng 10% sau 7 tuan bdo qudn d cdng thfte TN.
Bang 1. Tac dung cQa ch§ pham polyethylene-candelilla va BQE-15 tai mirc ton thit khdi lirQ'ng tg* nhien vi ty If thdi hong cua cam Ham Yen trong qua trinh bao quan
Cic chi tigu
T^ 10 t6n thit kh6i lu'(?ng ty nhi§n (%)
TJ 1$ thoi hdng (%)
Thoi gian bao quan (tu&n)
1 2 3 4 5 6 7 f
2 3 4 5 6 7
Cdng thirc thi nghifm DCI = Doi chd'ng
9,27^
13,33^
15,67^
20,91' 24,60' 26.58*
29,87*
0 5 15 20 30 35 45
DC2=BQE15
1,65"
2,91"
4,16"
5,78"
7,08"
9,23"
10,89"
0 0 0 5 10 10 15
TN=PE-CDL
1,79"
2,89"
3,86"
5,19"
6,67"
7,38"
8,57"
0 0 0 5 5 5 10 (Cic gii trj trong cimg mOt hing cd chl s6 mO khic nhau thl khic nhau cd y nghTa & miic a = 0,05)
3.2. Tac dung cua cac c h l pham tao mang td^i do chic va biln d6i mdu sic qua trong qua trinh bao quan
Tft hinh 1 cho thdy do chdc qua cfta tdt ca cac cdng thfte deu giam dan theo thdi gian bao quan, nhung su gidm giua cac cdng thfte la khdc nhau. O cdng thfte DCI cd su gidm ve dp chdc tft 6,8 kg/cm^ xudng 2,7 kg/cm^ sau 7 tudn bdo qudn. Trong khi dd a hai cdng thuc cd sft dung che phdm tao mang, sau 7 tudn dp cftng mdi gidm xudng 3,7 kg/cm a cdng thfte TN va giam xudng 3,0 kg/cm^ d cdng thfte DC2. Nhu vdy, cdng thfte qua cd dp chdc cao nhat Id cdng thuc TN phft che phdm polyethylen-candelilla.
Cling tft hinh 2 thay rdng xu hudng chung cfta cac mau cam cd sir biln ddi mau tang ddn theo thdi gian bdo qudn. Giai doan ddu thi tat ca cdc mdu cd su bien ddi mau sac tang manh. Mdu DCI cd tde dp biln mau nhanh nhdt (AE sau 2; 3 va 4 tudn tang tuomg ftng 41%, 64% vd 77%)i Cdc mdu qud d TN va DC2 cd su biln mau vdi toe dp cham hom. Trong giai doan sau, nhin chung qua trinh biln ddi mdu sde dlu tang nhung tde dp biln mdu cua cac mau dlu gidm ddn.CJ ddy cd su khdc biet rd rang gifta cdng thfte DCI va cdng thfte TN vl mau sic. Su khdc biet gifta cdng thfte DC2 va cdng thfte TN vl biln ddi mau sde qua la khdng cd y nghia d mftc y nghla a = 0,05.
:in2) ic cua qua (kg/(
J 3 ( O .
7.0 , 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5
(
\ - # - 0 0 1
\ - » - B C 2
\ A TN
^•--..^.^^^
) I 2 3 4 5 6
Thoi gian bao quan (tuan)
1
j
i
!
! 1
i
7
16 14 u 12
«n S
S 10
•<s
'£
6 4
Hinh 1. S\f biln doi dg chac cua cam HY trong qua trinh bao quan
2 3 4 5 6 7 Thoi gian bao quan (tu^n)
Hinh 2. S\f biln d6i mau sic qua (AE) cua cam HY trong qua trinh bao quan
3.3. Tac dung cua cac chl phim tao mang td'i cu'd'ng do hd hip ciia cam Ham Yen trong qua trinh bao quan
Kit qud khdo sat tde dung cfta cdc chl phdm tdi cudng dp hd hdp (CDHH) cfta qud cam neu tren hinh 3. Tft kit qua thdy xu hudmg chung Id gidm CDHH d tdt ca cac cdng thfte ftong qua trinh bdo qudn. Cdng thfte DCI cd cudng dp hd hdp cao nhdt tai tat cd cdc thdi dilm xdc djnh. Su khdc biet cfta DCI so vdi hai cdng thfte phu mdng trong giai doan ddu bao quan la rdt ldn vd gidm ddn vl sau. Giua hai cdng thfte phft mdng thi qua d cdng thfte TN cd CDHH thdp ban so vdi DC2. Mac dft su khdc biet cd y nghia ve mat thdng ke, nhung ve tri sd Id khdng ddng ke so vdi CDHH d cdng thfte doi chftng. Sir khdc biet vl CDHH gifta cac cdng thfte la do mdng dd c6 tde dung ngan cdn trao ddi khi ldm fte chl hd hap. Su tich luy khi CO2 ben trong qud cung cd the lam anh hudng din gia tri thuc cfta CDHH khi xdc djnh dua vdo nong dp khi nay trong hOp do kin cfta thilt bi. Sir khdc biet CDHH gifta hai cdng thfte tao mang DC2 va TN la do su cd m|t cfta sdp candelilla. Nhu vdy cd the thay rdng, mang phft da cd tac dvmg h^n che qud trinh hd hap cfta qua.
3.4. Tac dung ciia cac c h l phim tao mang td'i ham lirvng chit rIn hda tan ciJa cam Ham Yen trong qua trinh bao quan
Kit qua neu tren hinh 4 cho thdy ham lugng chdt rdn hda tan tdng sd (CRHITS) cfta dich qua cam Ham Yen tang dan trong qud trinh bdo qudn, trong dd cdng thfte DCI cd mftc tdng nhanh va cao horn so vdi hai cdng thfte cdn I?ii, cu thl tang tft 9,0 len 11,2° Brix sau 5 hidn bdo c[uan va len 12,0° Brix sau 7 tudn bdo quan. Hai cdng thfte qua TN vd DC2 chi cd sir khdc biet vl CRHTTS xdc djnh d thdi dilm sau 2 vd 3 tudn. Tai cudi ky bdo qudn sau 7 tudn, cd hai cdng thfte phft mang cd ham lugng CRHTTS khodng 11,1° Brix. Hien tugng tang CRHTTS cung dugc mdt sd nghien cftu khdc ghi nhdn khi bdo qudn qud cd mfti (Peeples et al, 2000). Mdt nguyen nhan cd the la do su mdt nudc qua vi cdng thfte DCI mdt nudc nhilu horn cd hdm lugng CRHTTS cao horn. Hai cdng thfte phft mdng it bi mdt nudc hom phft hgp vdi hdm lugng CRHTTS thdp ban.
3.5. Tac dung cua cac chl phim tdi ham lu'O'ng axit h&u co* t6ng sd va vitamin C cua cam Ham Yen trong qua trinh bao quan
Tft hinh 5 cho thdy d cac cdng thfte phu mdng cd dp gidm hdm lugng axit hftu co tdng sd it horn so vdi cdng thfte DCI. Cu the Id sau 7 tudn bdo qudn thi d hai cdng thfte phft mang Id DC2 va TN ham lugng axh hiru ca tdng so Idn lugt la 0,38% vd 0,39% (gidm 40,6% vd 39,1% so vdi mau ban ddu) trong khi dd d cdng thfte DC 1 thi sau 7 tuan bdo qudn hdm lupmg axit tdng sd Id 0,34% (gidm 46,88% so vdi mau ban dau). Vdi viec tang hdm lugng chdt rdn hda tan vd gidm hdm lugng axit d cdng thfte ddi chftng nen ty 1? gifta hai thdng sd nay d cdng thfte ddi chftng cao ban so vdi hai cdng thfte phu mang.
2 3 4 5 T h d i g i a n bAo q u d n ( t u a n )
2 3 4 5 Th&l gian bao quan (tuin)
Hlnh 3. Sif biln d6i cu'd'ng dg hd hSp cua cam Him Ydn trong qud trinh bao quan
Hinh 4. S\f biln d i i ham lu'O'ng chit rin hda tan ting sd cua cam Ham Yen trong qua trinh
bao qudn
2 3 4 5 T h M gian bim quin ( l u i n )
I 2 3 4 S 6 7 TliAi gian bio quin (tuAn)
Hlnh 5. Sv biln d i i hdm lu^ng axit hiru co cua cam Hdm Ydn trong qud trinh bdo qudn
Hinh 6. S\f biln dii ham lu'p'ng vitamin C cua cam Ham Ydn trong qud trinh bao qudn
Tft hinh 6 cho thdy cdng thfte ddi chftng DCI cd do giam vitamin C ldn hom d cdc cac cong thfte dugc phft mdng. Cu thl, d cdng thfte DC 1, hdm lugng vitamin C tft 78,55 mg% gidm xudng 45,58 mg% sau 7 tuan bao qudn (giam 42% so vdi ngdy ddu). Cdn dr cdng thfte DC2 sau 7 tudn bdo qudn thi ham lugng vitamin C gidm tft 78,55 xudng 50,24 mg%
(gidm 36%) vd d TN la 56,8 mg% (gidm 27,68%). Nhu vdy cd thl thay rdng, qua cam Ham Yen d hai cdng thfte phft mang cd ham lugng vitamin C gidm it hom so vdi cdng thuc DCI.
3.6. Danh gia chit lu'O'ng cam quan qua cam Ham Yen sau 7 tuin bao quan Kit qua tft bang 2 cho thay cam Hdm Yen sau 7 tudn bdo quan a cdng thfte TN vd DC 2 dlu cho kit qud tdt ban hdn so vdi d cdng thfte DCI. Vl hinh thfte, cam cd phft mdng dat dilm trung binh tft 3,83 din 4,17 dilm (cam DCI la 2,50 dilm), cam tuai, vd qua bdng. Vl miii vj, cam phft mdng cd dilm tft 4,17 din 4,67 dilm (cam DC 1 Id 3,25 dilm). Ve huang tham cam phft mang cd dilm tft 3,67 din 4,00 dilm (cam DC 1 la 2,50 dilrn). Ve do gidn cfta tep cam phii mdng cd dilm tft 3,83 din 4,67 dilm (cam DC 1 la 3,0 dilm). Dilm cfta hai cdng thfte phft mang DC2 vd TN khdng khdc nhau cd nghia d mftc y nghia a = 0,05.
Bang 2. Chdt lu'p'ng cdm quan cam Ham Yen sau 7 tudn bdo qudn
CT
DC1 (Doi chO-ng) DC2 (BQE-15) TN (PE-CDLL)
Hinh thiFC ben ngodi
2,50"
4,17^
3,83^
Chdt lu'O'ng ben trong Vi
3,25^
4,67^
4,17^
Hirong thorn 2.50"
4,00^
3,67^"
Dp gidn t6p 300"
4.67' 3,83' (Cic gia tri trong cimg mgt cgt cd chi so mu khic nhau thi khic nhau co nghTa a mirc y ghTa a=0,05).
III. K^T LUAN
Che pham tao mang polyethylene-candelilla da cd tac dimg tot trong bdo qudn qud cam Ham Yen. Sau 7 tudn bdo qudn, ty le hao hut khoi lugng tu nhien Id 8,57%>, ty 1? thdi hdng la
10%, trong khi d cdng thuc ddi chftng, cdc ty le dd Idn lugt la 29,87%» vd 40%.
Nhd cd phft mang ma cdc chi tieu ca ly vd sinh Iy nhu do chdc qua, biln ddi mdu sac va cudng do hd hap deu dien ra theo chieu hudmg cd lgi de duy tri hinh thfte va chat lugng cam quan cfta qud. Cac chi tieu hda hoc vd dinh dudmg nhu ham lugng chat rdn hda tan tdng sd, axit hftu ca tdng sd va ham lugng vitamin C deu bien ddi chdm hom nhilu so vdi ddi chftng khdng phft mang. Chat lupmg cam quan cua qud dugc phft mdng cung tdt hem do qud cdn tuoi, gift dugc mfti vj, huomg tham dac trung vd do chac cfta tep qua.
Hieu qud bao qudn qud cam Ham Yen bang che phdm tao mang polyethylene-candelilla hoan todn tuomg duomg vdi che pham BQE-15, thdm chi cdn vugt trdi ban khi xet tdi thdng so do chdc qud.
TAI LIEU THAM KHAO
1. Faber J. N., Harris L. J., Beuchat L. R., Suslow T. V., Gomey J. R., Garrett E. H., Busta F. F., 2003.
Microbiological safety of controlled an(i modified atmosphere packaging of fresh and fresh-cut produce. Comprehensive reviews in Food Science and Food safety, 2 (supplement), 142-160.
2. Hagenmaier R. D., 2000. Evaluation of polyethylene-candelila coating for "Valencia" oranges.
Postharvest Biology and Technol., 19, 147-154.
3. Hagenmeier R. D., Goodner K., Dou H., Rouseff R., 2002: Storage of "marsh" grapefruit and "Valencia"
oranges with different coatings. Proc. Fla. State Hort. Soc, 115, 303-308.
4. Park H. J., 2000. Development of advanced edible coatings for fruits. Trends in Food Science and Technology, 10(8), 254-260.
5. Paul B. K., Moulik S. P., 2001. Uses and application of microemulsions. Current Science, 80 (8), 990-1001.
6. Peeples W. W., Albrigo L. G., Pao S., Petracek P. D., 2000. Effects of coatings on quality of Florida Valencia oranges stored for summer sale. Proc. Fla. Sta. hort. Soc, 112,126-130.
7. Plotto A., Baker B., 2005. Review of wax-based and other coatings for fruits and vegetables. IFOAM Technical Paper, July 14,2005.
Summary
EVALUATION OF POLYETHYLENE-CANDELILLA COATING FOR "HAM YEN"
ORANGES
The study aims to evaluate the preservation effectiveness of the fruit coating, which composed mainly of polyethylene and candelilla waxes on the Hdm Yen orange storing under ambient condition for 7 weeks. As far as comparision is concerned, the experiment lias been added with BQE-15, one fruit coating imported from USA. The final result showed that polyethylene-candelilla composit emulsion provided much better preservation effectiveness
compared to the uncoated control, and it is quite equal to that of the imported BQE-15 coating.
During storage period, the respiratory rate, firmness, peel colour and total soluble solid content in two coated fruit formulas have been changed lesser and slower compared to those of uncoated control formula. After 7 weeks, the weight loss and spoilage percentage of fruit coated with polyethylene - candelilla emulsion stood at lowest rate, 8.6% compared to that highest level of the control, 29.9%. Both of coated fi-uit formulas have been kept in good quality that met the requirement for market.