Cong Nghe Sau Thu Hoach Va Ke Hoach Tap Huan Du An

AVRDC-ADB RETA 6208 Ci thin sinh k nng thn thng qua pht trin cng ngh sau thu hoch cc nc Lo, Vit Nam v Cambodia

TI LIU TP HUN

Cng ngh

`

ADB RETA 6208: Ti liu tp hun vsau thu hoch v khoch tp hun d n RETA 6208 Cng ngh sau thu hoch c chua v t cay. Page 1 of 69

Danh sch

Cc tc gi tham gia bin son

1. TS. Antonio L. Acedo Jr. Chuyn gia t vn v cng ngh sau hoch,

D n ADB-AVRDC RETA 6208 (Tham gia bin son phn A, B, C,

D v F).

E-mail: [email protected] ;

Website: www.avrdc.org/postharvest

2. TS. Chu Don Thnh. iu phi vin Quc gia, D n ADB-AVRDC

RETA 6208; Trng B mn Bo qun ch bin , Vin Nghin cu rau

qu, Tru Qu, Gia Lm, H Ni (Tham gia bin son phn A v B).

E-mail: [email protected] ;

Website: www.freewebtown.com/bqcb

3. ThS. Borarin Buntong. Chuyn gia v cng ngh sau thu hoch, Khoa

Cng nghip nng thn, i hc tng hp Hong gia, Phnom Penh,

Cambodia. (Tham gia bin son phn C).

E-mail: [email protected]

4. Mr. Vilayphone Keosilapheth. Chuyn gia v ch bin thc phm.

Khoa cng ngh sau thu hoch v ch bin, i hc tng hp Quc gia

Lo, Vientiane, Lo. (Tham gia bin son phn D).


5. TS. Sing Ching Tongdee. Ch tch hip hi cc nh bun bn v xut

khu tri cy Thi Lan, Kangkok, Thi Lan. (Bin son phn E).


ADB RETA 6208: Ti liu tp hun v Cng ngh sau thu hoch c chua v t cay. Page 2 of 69

Danh sch

cc cn b tham gia bin dch ti liu sang ting Vit

1. TS. Chu Don Thnh. iu phi vin Quc gia, D n ADB-AVRDC

RETA 6208; Trng B mn Bo qun ch bin , Vin Nghin cu rau

qu, Tru Qu, Gia Lm, H Ni.

2. KS. Lng Th Song Vn. Cn b B mn bo qun ch bin, Vin

nghin cu rau qu, Tru Qu, Gia Lm, H Ni.

3. KS. Nguyn Th Hnh. Cn b B mn Bo qun ch bin, Vin

nghin cu rau qu, Tru Qu, Gia Lm, H Ni.


Mc lc

A. C chua 6

Gii thiu chung 6

Thu hoch v x l ti rung 6

Cc cng on trong nh ng gi 10

Bo qun 20

Vn chuyn 25

Tiu th 28

Ti liu tham kho 29

B. t cay 32

Gii thiu chung 32

Thu hoch v x l ti rung 32

Cc cng on trong nh ng gi 33

Bo qun 35

Vn chuyn v tiu th 36

Ti liu tham kho 37

C. K thut sy t v c chua 38

Gii thiu 38

X l nguyn liu 38

Cc ch v thit b sy 40

Ti liu tham kho 52

Bi tp thc hnh 54

D. K thut ch bin Paste v Puree c chua 55

Ch bin paste c chua 55

Ch bin puree c chua 58

Bi tp thc hnh 59

E. Qun l cht lng rau qu 60

M u 60

Gii thiu chung 60


Cc c th ring ca rau qu 60

Cng c quyt nh s tn ti v tnh cnh tranh ca rau qu 62 Thng tin qun l h thng cung cp rau qu 63

Kt lun 64

Ph chng 64

F. Hun luyn t chc tp hun 67

Gii thiu chung 67

Lp k hoch tp hun 67

Lp k hoch tp hun tip theo (TMP) 69


CNG NGH SAU THU HOCH C CHUA T TI

A. C CHUA Gii thiu chung

C chua (Lycopersicon esculentum) l mt loi rau ph bin v c tiu dng rng ri vi s lng ln. cc nc Lo, Vit Nam v Cambodia cng nh nhiu nc khc, c chua thng c tiu th ti ch nh mt mn n ti hoc nu chn, v ch bin thnh mt vi dng sn phm khc nh nc st, nc c chua ung, dng bt, dng nhuyn. Ngoi gi tr kinh t, c chua v cc sn phm ca c chua cn l ngun dinh dng cho c th ngi, vi ngun axt folic, vitamin C, kali, v quan trng hn l hp cht carotenoid (tin vitamin A c hot tnh khng oxy ha), trong c mt nhiu nht l lycopene, sau l -carotene, -carotene v phytoene. Cc cht dinh dng khc trong c chua c vitamin E, cc nguyn t vi lng, hp cht flavonoid, phytosterol, v mt vi loi vitamin tan trong nc (Beecher, 1998).

Mc d c nhiu s pht trin v loi ging c cht lng tt v thi hn bo qun di, cng nh s ci tin v h thng sn xut, i vi c chua vn cha c s tin trin ng k c bit l cc nc ang pht trin nh Lo, Vit Nam v Cambodia, tn sau thu hoch ln do thu hoch khng ng thi im nn t l thi hng v tn thng c hc cao. V hu qu l gi bn ti rung thp, nhng gi bn l vn cao, s thua thit thuc v ngi nng dn v ngi tiu dng, thu nhp ca nng dn thp. Mt s yu t gy tn tht sau thu hoch v mt s yu t c tnh k thut bao gm thu hoch, x l v bo qun khng ng cch, bao gi v h thng vn chuyn km, thiu cc kho bo qun, v thiu k thut ch bin.

Trong ln tp hun gn y nht, cc nguyn nhn gy tn tht, s lin quan n k thut, v vic pht trin nghin cu cng ngh sau thu hoch cho c chua ti v c chua ch bin, ph hp vi tng nc c tho lun. Trong hi tho o to ny, cc cng ngh n gin v chi ph thp, v cc k nng thc hnh i vi tng giai on khc nhau ca cng ngh sau thu hoch, t thu hoch n ch bin, cng c gii thiu. Cc cng ngh ny l kt qu trc tip hoc gin tip ca vic nghin cu. Ch ny cp n c chua ti trn th trng, khng nhm vo cc quy trnh ch bin.

Thu hoch v x l ti rung

Bn yu t chnh c quan tm trong v ngay sau khi thu hoch c chua l chn thu hoch, thi gian thu hoch, phng php thu hoch v x l qu thu hoch ti rung. Bt k s thiu st no i vi nhng yu t ny u dn n gim cht lng qu, thm ch l tn tht hon ton.

chn thu hoch: C chua c th thu hoch khi qu t chn-xanh ( thun thc v mt sinh l nhng cn xanh v), hoc ng mu, hoc chn hon ton, ty vo mc ch s dng, thi gian vn chuyn, hoc khong cch t ni sn xut n ni tiu dng hoc th trng.


i vi nhng th trng xa, hoc i hi thi gian tn tr lu, c chua c thu hoch khi cn xanh hoc hi (ang chuyn mu). L mt th qu h hp t bin, c chua thu hoch khi cn xanh nhng thun thc th c th chn tip t nhin, v c th t n cht lng ti u. Ngc li, qu non s khng t c mu sc v hng thm tt, v s d dng b h hng sau thu hoch (Bautista and Acedo, 1987).

Hnh 1: Mu c chua t chn-xanh c th thu hoch

C chua chn-xanh c xc nh bng v d mu c th nh nh 1. Mu i din ny c ct cho, v nu nh cc ht ca mt ct khng b ct, v cc qu th tng ng nhau v kch thc, hnh dng, th c coi l chn. Trong sut qu trnh vn chuyn, c chua chn-xanh c th chu c iu kin b mt lu tr rp, x x tt hn, v th m vic tn tht cht lng v s lng l ti thiu. Tuy nhin, c chua chn-xanh c th khng t chn yu cu khi n thi im bn hoc tiu th, nn vic cho qu chn t nhin sau thu hoch, hoc lm chn nhn to l cn thit. Qu c mu hng hoc chn thng c thu hoach do nhu cu ca ngi tiu dng hoc nh ch bin.

Hnh 2: Thu hoch c chua trng thi chn khc nhau da vo mu v i vi cc th trng gn, c chua c th thu hoch khi ang ng mu, c

mu hng hoc chn hon ton. Cc trng thi ny c th xc nh d dng v chc chn da vo mu v (Hnh 2). Trng thi khc nhau v chn ca c chua c minh ha da vo bng mu trong bui hi tho cui. Hn na, hin nay c rt nhiu ging c chua l sn phm ca cng ngh sinh hc nh c chua ESL thi hn bo qun di, bin i gen hoc khng (Suslow v Cantwel, 2005). Nhng ging khc nhau ny nu thu hoch qu trng thi chn-xanh th qu trnh chn s b nh hng. V vy, t nht qu phi c thu hoch khi v hng.

Thi gian thu hoch: Nn thu hoch khi tri mt, v tt nht l vo bui sng, v khi nhit thp c th gim thiu s tng nhit ca qu, ng thi


tng hiu qu thu hoch. Bt u thu hoch khi sng sm tan ht, hoc nu thu hoch vo lc qu sm th cn cn thn ch iu ny trnh gy hi cho nhng cy vn cn qu cho t thu hoch sau.

Khng nn thu hoch khi tri ma hoc ngay sau khi ma, v t l mc bnh c th cao hn (Bautista v Acedo, 1987). Nc ma c th tch t trn cung qu, l ni xm hi chnh ca vi sinh vt, to iu kin thun li cho vi sinh vt pht trin. Tuy nhin, nu khng trnh c iu ny, qu cn phi c ra sch v lm kh trc khi bao gi (Xem phn Cc cng on trong nh ng gi). Vic ra v lm kh cng cn thit i vi qu t cc cy khng c cc hoc khng c li chn t, v t l ngun cha vi sinh vt gy hi, c th bm vo qu c bit l trong ma ma.

Phng php thu hoch: Phng php thu hoch thng dng l hi qu bng tay (Hnh 3)

Hnh 3: Thu hoch c chua bng tay

Hi qu ra khi cy cn trnh gy tn thng cy, v khng cn thit phi ri i phn cung nh, lm l ra phn cui cung, l ni trao i kh ch yu ca qu (v d, y l ni thot hi nc, gy mt nc v gim khi lng; l li vo ca O2 v li ra ca CO2, v th lm tng cng h hp v cc hot ng trao i cht khc). Mt vic khc cn lu khi thu hoch l phi quan st trnh tn thng c gii, nh mt vt thng nh gy ra do mng tay ca ngi thu hoch. Nhng vt thng nh nh th c th khng d dng nhn thy nhng qu xanh, nhng s thy sau khi vt thng chuyn sang mu en.

Hnh 4: Dng c thu hoch c chua vi b mt nhn


Dng c cha khi thu hoch, tt nht l c lm bng nha c b mt nhn (nh thng hoc khay nha nh). Dng c ny thng thun tin cho vic ng mt lng nh, v khng gy tn thng qu.

Lu tr trn ng rung: Cn trnh nm qu vo r thu hoch, hoc khng nn qung ko mnh cc r thu hoch. Nu khng, nhng va chm c th dn n nhng triu chng khng nhn thy c nh vt thm nu hoc en phn ht. Cc st ln c s dng thun tin cho vic cha ng v vn chuyn sn phm t ng rung n ni ng gi. Nn s dng cc r nha, nhng cng c th s dng cc vt cha n gin nh st tre. i vi cc st tre, hoc thng g, c th lt l hoc giy bo c bo v qu trnh b mt ca vt cha.

Cc thao tc khng ng cch trong qu trnh lu gi trn ng rung bao gm: nm qu vo thng cha, lm ri hoc ko mnh dng c cha trong qu trnh vn chuyn. Nhng thao tc ny c th dn n c cc tn thng vt l nhn thy v khng nhn thy. Cc vt thng nhn thy c th l cc vt ct, l thng hoc vt try xc. Ngoi vic nh hng n cht lng cm quan, cc tn thng vt l cn lm tng s mt nc v tc chn, v dn ng cho vi sinh vt xm hi.

Hnh 5: Qu nng ln do b phi di nh mt tri suy gim nhanh cht lng do

mt nc, qu nhn nheo v tng tc chn. C chua sau thu hoch c gi tm thi di bng rm, trnh phi ra di

nh nng mt tri, v iu ny gy rm nng, mt nc nhanh dn n kh nhn, v tch ly nhit thc y qu trnh chn. S tng nhit ca qu thng thy khi qu b phi nng mt n hai gi. Nhit tch t bn trong qu s c gii phng sau v lm tng nhit bn trong vt liu bao gi, vt chuyn ch hoc khu lu tr. ng thi n lm tng cng h hp. loi b nhit, cn lm mt s b (xem phn Cc cng on trong nh ng gi).

Qu c thu hoch nhng chn khc nhau c th phn loi trong qu trnh thu hoch v qu trnh lu gi trn ng, bng cch chng trong cc vt cha khc nhau hoc trong cc thng cha c ngn.


Hnh 6: Dng c thu hoch v vn chuyn c tm ngn chia qu xanh v qu chn.

Phn loi qu ty thuc vo kch thc v ng thi c th phn loi khuyt

tt nu ngi thu hi c kinh nghim. Nu khng, qu s c vn chuyn n nh bao gi lm vic ny.

Cc cng on trong nh ng gi Hot ng chnh trong nh bao gi l ng gi trc khi bo qun hoc vn

chuyn n th trng. Mc d vy, cc cng vic khc trc khi bao gi cng cn thc hin sao cho tn tht l thp nht trong sut qu trnh vn chuyn v tn tr, v t c yu cu cht lng trong sut qu trnh lu thng trn th trng v tiu dng. Cc cng vic trc bao gi i vi c chua bao gm lm sch, phng nga thi hng, phn loi tuyn chn, x l kim sot qu trnh chn, v lm mt s b. ng thi cn thit k mt nh bao gi.

Nh ng gi n gin: Mt kt cu n gin c mi che hoc nh mt tng c th c ci thin thnh mt khu cho cc cng on bao gi trong nh khc nhau, c minh ha trong hnh 7A (FAO, 1986). Thc t s dng cho c chua c th hin hnh 7B. Yu cu ti thiu l sn v mi che thch hp, s thng gi y , v c khu phn loi, bao gi, x l theo yu cu ca tng mt hng (v d ra sch/lm kh, x l chn), v lu gi qu ng gi. Sn nh ti thiu cho mt tn qu c lu tr l 20m2.


Hnh 7. Nh bao gi c chua n gin, ni tin hnh cc hot ng nh la chn,

lm sch v ng gi. cc nc Lo, Cambodia v Vit Nam, nhiu cn nh ca nng dn c

xy dng cao hn 8 10 feet (1 feet = 0,3048 m) so vi mt t, v khong trng c dng lm ni ngh ngi hoc ni lu tr cc dng c nng nghip. Hoc khong t trng ny c th chuyn thnh nh bao gi, nu khng gian khng th c th m rng bng mi che.

Lm sch v kim sot thi hng: C th s dng vi mm lau sch qu trong qu trnh phn loi, hoc c th ra bng nc sch, sau phi lm kh. Trong qu trnh ra, nc ra c th b nhim bn v cha vi sinh vt gy thi hng nu khng thng xuyn thay nc. x l phng bnh, c th s dng cc cht thng thng c php s dng (General-Regarded-Ss-Safe - GRAS) nh Clo di dng cht ty ra (5.25% HypoChlorit NaOCl), v mui cacbonat nh Natricacbonat. Nhng nghin cu trc y ch ra rng, phng php x l n gin ny s lm gim thi hng mt cch c hiu qu. Tuy vy, i vi tng ging phi s dng nng thuc thch hp. Khi x l bng HypoClorit, cn lu mt s im sau y:


1. Ra trong nc Clo (NaOCl 50-70ppm) trong 2 pht, sau ra bng nc, c th phng nga s thi hng gy ra do vi khun, nm mc v nm men (Ogawa v Manji, 1984).

2. Nh mt cht ty u cho c chua, 4 tha c ph (tng ng 20 ml) thuc ty thng mi c thm vo mt Gallon nc sch (1 Gallon = 4,53 lit), s tng ng vi NaOCl khong 250 ppm (Bautista v Acedo, 1987).

3. Tnh trng suy gim cht lng ca c chua trong qu trnh lm mt bng bay hi, c th c hn ch nh nhng trong NaOCl mt pht, nhng vi nng cao hn, khong 0.5 1.0%, tuy nhin iu ny c th khng an ton (Acedo, 1997).

Khi s dng mui cacbonat (v d kim cacbonat hoc ph bin l Natricacbonat), nng 3% (30g/l) th nn dng phun ln qu hoc nhng qu, sau ra vi nc (Smilanick 2002).

Sau khi ra, cn lm kh qu v s m t bn trong vt cha s to iu kin thun li cho vi khun pht trin. Vic ny c th thc hin d dng bng cch lau qu, hoc qut bng khng kh thch hp. Trong sut qu trnh ra hoc lm kh, c th tin hnh mt s cng vic trc bao gi nh phn loi tuyn chn.

Phn loi/tuyn chn: C chua c cht lng tt lun l s la chn u tin ca ngi tiu dng. V th, phn loi hay tuyn chn lun l vic lm c li. Phn loi v tuyn chn c th thay th cho nhau, nhng tht ra gia chng vn c s khc bit. Khi phn loi da trn tiu chun la chn chnh thc ca cng nghip th c gi l s tuyn chn. Nhng qu trnh n gin hn gi l phn loi.

Phn loi hay tuyn chn bt u bng vic phn bit nhng qu c cht lng tt vi nhng qu km cht lng, hoc b khuyt tt (nhng qu b rn nt, bin dng, thi hng, b cn trng hi, hoc b cc vt thng vt l). Nhng qu tt sau s tip tc c phn loi theo mc cht lng, da vo kch thc v chn. Nh th, phn loi v tuyn chn s xc nh cht lng v gi thnh ca sn phm hng ha khi a ra th trng. Nu thiu cc tiu chun cht lng th s l ro cn thng mi, v s cn tr s pht trin v tnh cnh tranh trong cng nghip. Trong thi i tng cng m rng thng mi v ton cu ho th trng, cc nc ang pht trin cn c c quan tiu chun ha v kim tra tiu chun la chn.

Phn loi v tuyn chn s trnh c s h hng sm ca qu. Nu ln cc loi qu khc nhau v cht lng, qu b bnh hoc b tn thng vi cc qu lnh ln s lm tng t l thi hng, v qu cht lng km hoc qu b tn thng rt nhy cm vi s pht sinh bnh, d dng b nhim bnh t qu b bnh, v c th dn n h hng c nhng qu lnh ln khc. Qu b bnh hoc b tn thng c gii thng sn sinh ra nhiu ethylene, mt hoocmon thc y qu trnh chn v gi ho. Vn ny s tr nn nguy him nu qu c tiu th th trng xa, nhng ni m thi gian vn chuyn c th phi ko di 3 5 ngy, nhit s tng, to iu kin thun li cho bnh pht trin. Cng khng nn ln qu cha chn vi qu chn, c bit l trong sut thi gian di vn chuyn v lu tr, v qu chn s sinh ra lng ethylene cao, gy ra s chn sm ca nhng qu cha chn.

cc nc Lo, Vit Nam v Cambodia v nhiu nc ang pht trin khc, khng c tiu chun la chn no vi c chua. S phn loi gia ni cung cp v


ni c nhu cu li khc nhau. C th phn loi da trn kch thc (v d A-ln, B-trung bnh, C-nh, D-rt nh), mu sc, hoc trng thi chn, v khng b khuyt tt. S phn loi theo ging cng quan trng v c chua c rt nhiu loi ging, khc nhau v nhy cm vi nhng tn thng c gii, v tc chn. C chua c tht dy thng chu c lu tr trong nhng vt dng b mt g gh tt hn so vi nhng ging tht mng. Nu c hai ging ny c lu tr trong cng mt ni, th tn thng c gii nhng qu mng tht c th dn n thi hng hoc gim cht lng nhng qu c tht dy, v lm tng tc chn. Mt s nng dn thng trng v thu hoch hai hoc vi ging cng mt lc. Cc qu khc ging c bao gi ln trong cng mt thng cha vn c th gi c cht lng nu ni sn xut gn ni tiu th. Tuy vy, nu mun thit lp mt ci tn cho sn phm c cht lng tt ca mnh, ngi nng dn cn phn loi sn phm theo kch c hoc yu cu cht lng ca ngi tiu dng. C th dn nhn hoc ng du cho sn phm, con du phi c bo v v cao ngun cung cp c chua cht lng cao. V tiu chun la chn c chua cha c s dng cho cng nghip cc nc ang pht trin trong c Lo, Cambodia v Vit Nam nn cch phn loi c ngh di y c th dng tham kho:

Loi A, ln: C chua ca cng mt ging, c cng trng thi chn, cng hnh dng, khng khuyt tt (khuyt tt do cn trng hi, tn thng vt l, thi hng, bin dng,)

Loi A, trung bnh: Cht lng yu cu nh loi trn, nhng khc v kch c. Loi A, nh: Cht lng yu cu nh trn, nhng khc v kch c. Loi B, ln: C chua ca cng mt ging, khuyt tt trn b mt hoc khuyt

tt nh (khuyt tt nh ngha l khng nh hng n cht lng qu khi n v nh hng khng ln n cht lng cm quan ca c l hng).

Loi B, trung bnh: Cht lng yu cu nh trn, nhng khc v kch c. Loi B, nh: Cht lng yu cu nh trn, nhng khc v kch c. Loi C, a kch c: C chua ca cng mt ging, khng c phn loi theo

trng thi chn, nhng khng c qu chn hon ton, c khuyt tt nh nh loi B, nhiu kch c.

Suslow v Cantwel (2005) a ra ch s cht lng tiu chun cho cc ging c chua khc nhau, trc ht l da trn s tng ng v hnh dng, v khng c khuyt tt, h hng. Kch c khng phi l yu t tuyn chn cht lng nhng c l nh hng kh nhiu n cht lng v mt thng phm. Cc ch s cht lng ny nh sau:

- Hnh dng: c cng mt kiu hnh dng (hnh trn, hnh cu, hnh cu dt) - Mu sc tng ng (t cam n m, vng nht). Khng c mu

xanh. - Biu hin bn ngoi: Trn mn, so cung nh. Khng c cc vt rn nt,

rm nng, vt thng do cn trng, vt thng c gii, hoc vt bm tm. - cng: Chu c p lc. Khng b bin dng do chn nu.

Trong qu trnh phn loi, tuyn chn, cng nhn phi c k nng thnh tho. cng on ny c tin hnh d dng, nn c cng c h tr, v d nh bn


phn loi n gin c lm bng cc thanh tre (b mt tip xc vi qu phi nhn) vi khung g, nh hnh 7B. Mt s kiu thit k khc Hnh 8.

Hnh 8: Bn phn loi c chua.

Mt ci bn phn loi di ng, nh hnh 9, c thit k theo kiu c th ng vo hoc d ra, c my iu chnh chiu cao ph hp v thun tin cho ngi phn loi, c bn quay vi ng phn chia (Reyes, 1998)

Hnh 9: Bn phn loi quay, di ng.

Hn na, tng hiu qu v chnh xc cng vic trong qu trnh phn loi, tuyn chn, nh sng phi c cung cp y , v cng nhn lm vic phi c thi gian ngh ngi ph hp.


Kim sot s chn: S chn ca c chua c th c lm chm li hoc tng cng, hoc ci thin. - Lm chm qu trnh chn l mc ch chnh ca tch lu, bo qun, ko di tui th sau thu hoch. Trnh qu trnh chn sm trong khi vn chuyn cng rt quan trng. Cc bin php k thut khc nhau lm chm qu trnh chn v ko di tui th c nhc n trong phn tn tr. - Vic thc y qu trnh chn cng cn dng n, c bit l i vi nhng qu thu hoch trng thi chn-xanh p ng nhu cu ca th trng tiu dng,v thm ch nhng qu c thu hoch trng thi khc nhau c th t c chn ng u theo yu cu. C chua chn thng l nhu cu ca ngi tiu dng hoc nh ch bin. Ch nn lm chn nhn to nhng qu trng thnh, v qu non chn p s khng tt. Phng php lm chn khc nhau c mt c ch chung tng tc chn l x l ethylene hoc nhng cht tng t (nh axetylene) trong mt khong thi gian kch thch qu sn sinh ethylene mc cao. Vic s dng kh ethylene i hi chi ph cao v my mc phc tp. C th lm chn c chua bng mt s k thut n gin nh sau: 1. S dng nguyn liu thc vt sn sinh kh ethylene cao nh l cy ca Gliricidia sepium v Samanea saman, hoc nhng qu chn, ang chn. Nhng nguyn liu ny thng c s dng vi lng thch hp l 10% trng lng qu (c 10 kg qu, th s dng 1 kg nguyn liu thc vt ny), trn ln vi qu trong mt bung kn 2-3 ngy, sau a qu ra khi phng v chn t nhin trong iu kin thong. 2. S dng dung dch Etan (ch phm thng mi l Ethrel ging vi ethylene dng lng) nng 2500-5000 ppm, nhng trong 5 pht. 3. S dng t n (CaC2), cho mt lng t vo ng qu gi trong phng nh, nn nh v khi c chua phi c ph kn bng bao ti trong 2 ngy acetylene gii phng ra t t n khi n phn ng vi nc, sau bao ti chn c d i, qu chn. Trong mt vi trng hp, qu c cha trong thng cha ln, sau t n c a vo trong mt ti nh, ph kn trong 2 ngy. Khong 0.25-0.5 kg CaC2 c gi trong giy bo v trong mt st tre 80 kg. Qu xanh s chuyn sang c mu sau 1 ngy t khi x l, trong khi chn t nhin th phi mt 6-7 ngy. Cn ch rng phn ng ca CaC2 v nc s sinh ra acetylene l mt phn ng to nhit, v th khng x l trong thi gian ko di v s dn n tn thng nhit ca qu, v d qu chn cng ch t c mu cam hoc vng, thay v mu .

- cc nc nhit i th ci thin s chn rt quan trng, v d nh Lo, Vit Nam v Cambodia, ni m iu kin nhit cao l ch yu, thung dao ng t 27 320C, khng thun li cho s hnh thnh mu ca qu c chua. Nhit chn ti u cho gi tr cm quan tt v cht lng dinh dng l 200C (Suslow v Cantwell 2005). Nhit ny cho mu sc tt nht v gi c nhiu vitamin C nht. Mu ca qu c chua l do carotenoid, lycopene, c tng hp nhit khong t 13 250C. Cao hn khong nhit ny s cho mu vng cam hoc vng nht, v -carotene c tng hp nhiu hn, trong khi thp hn khong nhit th qu c th b tn thng lnh (khng chn c, hoc b nu ha b mt). Mu hnh thnh qu c chua khng phi l mt vn nhng vng t cao, ni c nhit thp, hoc khi lu tr kho lnh trong cc ch bn bun, bn l. nhng


vng t thp hoc khi nhit cao, c th lm cho c chua chn bng cch gi qu trong khu mt, hoc trong mi cht lm mt d bay hi (v d mn ca m, cht lm mt bay hi xem thm trong phn Bo qun).

Lm lnh s b. Lm gim nhanh chng nhit sn phm, mt qu trnh c gi l lm lnh s b, c th gip gi c cht lng thng qua vic lm chm cc hot ng trao i cht. Lm lnh ngay sau khi thu hi c th gi cht lng rau qu mc tt nht sau thu hoch. Nu c thc hin kt hp vi bo qun lnh, n c th lm gim thi gian lm lnh. Lm lnh khng kh cng bc l c hiu qu nht nhng phng mt li ph bin hn (theo Suslow v Cantwell, 2005). Mt phng php n gin v nhanh chng ca lm lnh s b l s dng nc lnh. Lm lnh nc n gin v gi thp c thc nghim ti Vin Nghin cu rau qu, H Ni, xem hnh 10. H thng ny gm mt b khung c lm t nhng ng nc v hai loi vt liu lt- u tin l nhng tm tre an, tm ct v tip theo l tm nilon ph ln trn- trc khi cho nc vo. Nc c lm lnh n 100C bng cch cho . Qu c th c nhng ngp trong nc lnh n khi nhit tm qu t 10-13oC.

Hnh 10. M hnh lm lnh s b n gin thc hin ti Vin NC Rau qu, H Ni

Vi quy m nh, lm lnh s b c th thc hin bng nhng ci r nha

hoc thng cha cng, cng vi nc v vn, nh v d hnh 11.

Hnh 11. Dng c lm lnh s dng vn v nc trong thng nha


Bao gi. H thng bao gi khng ch c chc nng cha sn phm m quan trng hn, n cn c s dng nh mt yu t bo v sn phm hu hiu, gip sn phm trnh nhng tc ng c hc v nhng nguyn nhn lm hao tn khc. Cc chc nng khc ca bao b l cung cp cc thng tin v sn phm bn trong nh: khi lng v nh gi bn ca sn phm, xut x sn phm v.v C nhiu loi bao b khc nhau c s dng bao gi v vn chuyn c chua nhng ph bin nht l cc st tre v st g c dung tch cha thay i t 20-60 kg (Hnh 12). Mt s t trng hp s dng st nha mc d chng kh t, nhng vn c gii thiu bi chng rn chc v c th ti s dng, hoc tr li, chng c b mt mm v d v sinh v c th xp thnh chng cao.

A CB

Hnh 12. Vt ng c chua: A-St tre, B-St g, C-St nha

nhng nc ang pht trin, st tre c dng ph bin v gi r v tre l nguyn liu truyn thng v thng dng. Tuy nhin khng ging nh nhng vt liu cng khc, nu khng s dng nhng bin php bo v ph hp th tc dng bo v rau qu t nhng tn thng vt l ca st tre l rt thp. St tre thng c b mt sc v gh gh, chng khng th chng ln nhau m khng lm dp nhng qu lp di nu khng s dng tm g lt hoc np y bng g gia cc lp, v cc st trng khng th chng ln nhau tit kim khng gian nu khng c thit k vi nhng cnh cho theo y nh hnh 12A. Thng g cng bo v sn phm tt hn st tre nhng nu khng lt b mt mt cch cn thn th n c th l nguyn nhn gy nn nhiu tn thng rau qu. Mun tit kim khng gian khi tn tr cc thng trng th c th thit k cc thng g dng c th gp li, xp li c (Hnh 13A) trong khi st nha c th lm cc cnh xin (Hnh 13B).

A B

Hnh 13. Thng g xp c (A) v st nha c cnh xin (B).


trnh hoc hn ch thp nht cc thng tn vt l v nhng hao tn khc qu, khi bao gi cn ch thc hin nhng im sau: a. S dng bao b sch b. Nu ti liu bao gi c s dng ph bin, vic ng gi d c thc hin ng u. Nhng bao gi cha t 40-50 kg l qu nng. Ngi ng gi thng lm ri hoc nm chng hn l nhc chng ln mt cch nh nhng trong sut qu trnh ng gi v vn chuyn. c. S dng nhng vt lt v vt m hoc nhng vt liu dng lt nh giy bo, l...(Hnh 14). Vi thng g, c th dn sn nhng tm ba cc tng mng pha bn trong (Hnh 15).

Hnh 14. S dng vt lt trong st tre v st g

Hnh 15.Thng cha g-giy (Ba cctng c gin cc mt bn trong lm lp lt)

d. Khng s dng nhng vt cha qu su v s d lm tn thng qu phn y. (Hnh 16)


B A

Hnh 16. Nhng thng cha qu su (A) s lm tn thng nhng qu nm phn

y, nn s dng nhng thng cha cn (B) e. Ch ng va dung tch cha ca bao b. Khng c n qu cht hoc ng qu y dn n nhng tn thng do bm dp (Hnh 17)

Hnh 17. Nhng thng cha qu cht lm qu b h hng

f. ng gi nhng qu c cng chn trong cng mt bao b. Nu xp ln nhng qu chn vi nhng qu cha chn c th dn n s chn p ca nhng qu cha chn v lm tng h hng nhng qu chn t trc. g. Gi c nh qu trong bao b lm cho qu khng x dch trong sut qu trnh ng gi v vn chuyn v hn ch thp nht h hng do va p. C th c nh qu bng cch lc nh bao b trong qu trnh ng gi lp y cc khong trng. Bao b c lm y ti 1/3 dung tch cha v lc nh; sau tip tc lm y n 2/3 dung tch cha v lc li bao b ln na. Tip tc qu trnh ny cho n khi bao b c lm y kht. h. Cn thao tc cn thn trong sut qu trnh ng gi (nh khng ri qu...) i. Buc cht bao b bng dng c chuyn dng hoc dy buc. j. Xp vo ni mt. C nhng bin php bao gi c th gip lm chm s chn v ko di thi gian tn tr ca c chua. Mt k thut n gin c ng dng kh ph bin mt s nc l bao b ci bin kh quyn (MAP), mt loi bao b chuyn dng c th linh ng trong mi trng bo qun. Loi mng MAP ny nn c s dng nh l yu t b sung hn kt hp vi cc vt liu bao gi khc l mt vt liu bao gi c lp v n c kh nng chng chu tc ng c hc km.


Bo qun

Khi qu c bo qun th mc ch chnh l tr hon s chn v ko di thi gian tn tr qu. Thng thng qu c em bo qun tm thi trong khi ch vn chuyn, bc vc, hoc ch n lc bn, nhng nng dn v ngi bun bn li khng mun sn phm ca h b chn sm. Nh vy, qu chn sm trong sut qu trnh vn chuyn l iu khng c mong mun. Nhng cng c nhiu trng hp, c chua c gi trong mt khong thi gian no i qu chn v lc chng c bo qun vi mc ch lm tng chn nhiu hn l ko di thi gian tn tr qu.

Nhng k thut bo qun khc nhau khi em ng dng bt c ni no u phi c kim nghim cho ph hp vi cc iu kin ni bng cch s dng cc ging a phng, yu t nh hng n cc phn ng trong qu trnh bo qun. Phng php hiu qu nht lm chm chn v ko di thi gian bo qun l bo qun nhit thp. Nu c c s bo qun lnh, nn lu cc iu kin sau y (Suslow v Canwell, 2005): Nhit : 12.5-15oC vi qu xanh; 10-12.5oC vi qu ng (c mu nht); 7-10oC vi qu chn (c mu m) m tng i: 90-95%

Qu c chua t chn k thut c th bo qun c n 14 ngy trc khi chn 12.5oC m khng lm gim cht lng cm qun v s bin i mu sc. nhit ny, sau qu 2 tun, s thi hng s tng dn theo thi gian bo qun. Vi nhng qu t chn ti ( chn s dng, n c), c th bo qun c 8-10 ngy khong nhit thch hp. Bo qun ngn hn hoc h nhit thp hn khong nhit nu trn i khi c p dng trong th trng nhng s d xy ra tn thng lnh sau mt vi ngy. C chua s xut hin tn thng lnh nhit di 10oC nu gi qu 2 tun hoc 5oC nu qu 6-8 ngy. Hu qu ca vic tn thng lnh l c chua s khng tip tc chn mt cch bnh thng, khng t c mu sc v hng v t nhin, qu b mm, b mt b lm, thm ht, v tng nguy c h hng (c bit l mc en gy ra bi vi khun Alternaria spp.). Bn cnh , m tng i cao cng cn thit cho vic gi cht lng c chua mc cao nht c th v chng li s mt hi nc (lm nhn v qu). m cao ko di cng l iu kin thun li pht trin mc trn b mt qu hoc nhn cung. nhng nc ang pht trin bao gm CLV, nhng c s bo qun lnh vn cn him. Nhng phng php bo qun khc l rt cn thit. Sau y l nhng phng php bo qun c chua n gin v r tin.

Bao gi iu bin kh quyn (MAP). MAP l mt phng php n gin v r tin lm c ch s chn ca qu bng cch to ra mi trng kh c t kh CO2 v nhiu kh O2. MAP cn to ra mi trng m lm gim s mt hi nc. MAP c to ra mt cch n gin bng cch cho qu vo trong mt ti cht do (hnh 18). Mng nilon cng c th c dng lm vt liu lt trong cc thng cha, hoc che ph, y cc pallet.


MAP fruits

Hnh 18. C chua bo qun MAP v khng bo qun MAP sau 6 ngy iu kin

thng (25-33oC)

Fruits stored in open

Nhng loi mng MAP c sn nhiu cc nc chu bao gm cc nc

lo, Vit Nam v Cambodia l cc loi ti LDPE v HDPE, mng polypropylene (PP) vi cc dy khc nhau. S pht trin cng ngh trong vic ng dng mng MAP tng thi gian bo qun c chua gm c nh sau: 1. C chua ging Daniella hybrid (thi gian bo qun di) cc trng thi qu xanh, qu ng v qu c mu ng trong ti PE c dy 44.4 m v bo qun 20oC ko di thi gian bo qun bng cch tr hon s chn thng qua s bin i mu sc, hm lng lycopen, cng v cng lm gim nhiu s hao ht khi lng (Ait- Oubahou, 1991) . 2. C chua ging Liberto trng thi hng gi c rt tt trong ti PE c dy 50 m v ti PP c dy 25m 13oC. Qu c chua vn cng sau 60 ngy bo qun v c s hao ht khi lng thp nht v cht kh ha tan cao nht. Nhng loi mng khc (PP 20m, PVC 10m) c tc dng thp nht. C chua mi trng bn ngoi th qu chn sau 30 ngy bo qun (Batu v Thompson, 1998). 3. Ti PE c dy 0.04mm c xem nh mt loi ti ti s dng c th cha c 90kg c chua ging Improved Pope trong cc r nha, vi hnh thc ny c th tr hon s chn ti 10 ngy (t 11ngy ca nhng qu iu kin thng n 21 ngy vi nhng qu bo qun trong ti PE) 22oC. Kt qu bnh qun, s qu chp nhn c l 74% vi nhng qu c gi mi trng bn ngoi v 85% vi c chua bo qun trong ti PE (Yaptenco v cng s., 2004). Trong ng dng ring mng MAP vi iu kin nhit cao cc nc nhit i, bn trong ti thng xy ra hin tng ng nc v c th dn n thi hng qu (Hnh 19). trnh tnh trng y, nhng loi mng ph hp vi dy thch hp phi c s dng hoc phi xc nh c thi gian ti a trong bo qun bng MAP trc khi xy ra cc hin tng nh vy. c l trn ti nilon cng tr nn cn thit. Cc l thng c th c c u n bng cch s dng cc vt dng di thng thng, inh ghim hoc nhng hng l kim chm siu nh. V d, khi s


dng LDPE 50 m th nn c 4 l inh ghim cho mi 4 kg qu trong khi vi st g c kch thc 36 x 48 x 24 th cn 24 l inh ghim.

A B

Hnh 19. Nc ng bn trong mng MAP (A) v lm hng qu bo qun bng MAP (B)

Bo qun lnh bng phng php bay hi (Evaporative Cooling System). ECS bao gm s bay hi ca nc mang theo yu t lm mt. Nc c cung cp vo nhng vng ln cn ca sn phm v lm h nhit trong bung bo qun, nhit sinh ra t chnh sn phm (nhit sinh ra do h hp) v do mi trng bn ngoi. S gim nhit c th khng qu ln nhng m c th tng ln t 90% hoc cao hn, ng dng ECS rt c hiu qu trong vic hn ch s mt nc v cc qu trnh lin quan n s mt nc (nh s ho, s chn nhanh). Cc phng php ECS khc nhau u c mt im chung s c mt ca nc vng ln cn sn phm: 1. S dng mn ca m - Mn ca c lm m vi nc t l 1:1 c th tr hon s chn ca c chua ti 2 tun v qu c chua vn tip tc chn (Hnh 20) (Bautista v Acedo, 1987). Mn ca phi c lm sch, bng cch di nc si, phi kh dit vi khun. Mt k thut khc dit khun l s dng dung dch Hypochlorite 200ppm lm m mn ca. Qu c chua nn c xp thnh tng lp mng, chng hn: mt lp mn ca dy khong 2 cm, tip theo l mt lp qu sau li ph ln mt lp mn ca, v c tip tc nh th. Cch ny c th ngn khng cho bnh ly lan t lp ny sang lp khc. Phng php ny c th thc hin nhiu khng gian hoc trong cc vt cha.

Hnh 20. S dng mn ca m trong bo qun c chua

2. S dng chum, vi lm m Nhng ci chum, vi ln rt sn cc vng nng thn c th c s dng lm ECS mc trung bnh (Hnh 21) (Bautista v Acedo, 1987). Chum c t trn mt ci khay nc v ph ln trn bng mt mnh vi m hoc bao ti lm t si ay. Phng php ny c th gi qu c chua chm chn t 1- 2 tun.


Hnh 21. S dng chum vi m bo qun c chua

3. T lm mt nh bay hi Hnh 22 cho thy T - mt kiu cu trc ca ECS c th gi c chua xanh trong thi gian bo qun lu gp i so vi c chua bo qun iu kin thng (Acedo, 1997a). Kiu cu trc th nht (Hnh 22A) gm c t bo qun lm bng g v li kim loi, ton b cu trc c ph bi bao ti ay c lm t bng nc trong khay t trn nh v di y. Cu trc th hai (Hnh 22B) l s ci tin ca cu trc th nht. Cc cnh hp c lm t tm Gl phng, c khong cch 5x5cm so vi cnh pha ngoi c lm bng li thp tt. Khong cch 1.5cm gia hai bc vch bn trong v bn ngoi cha y tru c gi t bng s tip xc vi mt tm vi ngm ngp trong khay nc t trn nh hp, c th thay tru bng than ci v mn ca. Cu trc th 3 (Hnh 22C) l mt cu trc phng to, khong gp 4 ln kch thc ca cu trc th 2, dng bo qun s lng ln. N khng c phn no c lm t g v c lm t nhng vt liu bn nh cc thanh st v tm Gl dy v li thp. h nhit, ta nhit bn trong t, phn nh t c bc tng thng gi. Mng ng nc cng nh t vi h thng ng nha dn nc vo lp tru dy 5 cm. Ton b cu trc ny t trn mt khay Gl cha nc.

A B C

Hnh 22. Thit b lm mt bay hi bo qun c chua

4. Thit b lm mt bay hi vi qut thng gi Hnh 23 cho thy cu trc ny c hai hp mng trn cc cnh i nhau c cha nhng b rm hoc than (Redulla v cng s., 1984). Nc c cho nh vo than hoc rm, v gi lm quay tuabin ht


hi m, kh mt c a vo lm mt sn phm bn trong t mt. Nhit bn trong t gim t 3-5oC trong khi m tng ln khong 85%.

Hnh 23. Thit b lm mt bay hi vi my ht gi

5. Thit b lm mt nh git Thit b lm mt bay hi di y, c xem nh mt thit b lm mt nh git, c lm t nhng vt liu a phng, nh tre v (Redulla v cng s., 1984). N gm thn t c lm t nhng thanh tre v che ph bng tm ci c lm t bng nc dn t mt ci vi thng qua nhng ng tre.

Hnh 24. H thng lm mt bay hi theo kiu nh git

6. T mt khng cn nng lng y l thit b lm mt bay hi, c dng ln vi hai lp gch, khng gian gia hai bc tng trong v ngoi c y ct t m nc (Hnh 25) (Roy, 1989). C chua c t bn trong v ton b t c


ph bng mt tm thm r tin gi m. Sut thi gian nng, t bo qun c th duy tr 15-18oC v 95%RH.

Hnh 25. Thit b lm mt bay hi kiu bung lm mt khng nng lng

Cc phng php ko di thi gian bo qun n gin v r tin khc. Mt

bin php hu hiu nhm lm chm s chn l s dng 1-methylcyclopropene (1-MCP), l cht c tc dng c ch hot ng ca ethylene v c y ban Mi trng v Cc kim nh thuc v thc phm Hoa k (US EPA v FDA) cng nhn l an ton cho ngi s dng rau qu . N c th lm c chua chm chn n 2 tun theo Improved Pope vi c chua c th s dng 250ppb 1-MCP trong 24 gi (Acedo v cng s., 2004). N cng c tc dng lm chm chn tng t trn c chua bi vi liu lng s dng 110ppb (Opiyo v Ying, 2005). Tuy nhin, trong c hai trng hp, qu c chua u khng t mu mong mun khi t s chn mm. Nhng x l ng thi khc sau khi x l 1-MCP c th cn thit qu c chua chn mt cch bnh thng v mu sc v. Mt x l khc cho thy cn thit s dng ethanol (Acedo v cng s., 1995). Bin php x l tt nht l 1 ml ethanol cho mi kg c chua trong 6 gi bng cch s dng phng php bay hi v 4% ethanol trong 4 pht khi s dng phng php nhng ngp. Vn chuyn

y l mt trong nhng cng on quan trng trong x l c chua bi v bt c mt thiu st no trong h thng ny (nh iu kin vn chuyn ngho nn, thao tc cu th, nhng s chm tr) u c th dn n nhng hao ht nghim trng (Hnh 26).


Hnh 26. iu kin vn chuyn ngho nn dn n nhng hao ht c chua nghim

trng

Nhng phng tin vn chuyn ch yu l xe bc hng, xe but v xe ti v chng thng khng c lm lnh. hn ch thp nht nhng hao tn, cn lu mt s im sau: a. Cch thc xp hng ph hp i vi cc st tre, t cc tm g ngn nm ngang gia cc lp trong khi hng trnh lm hng qu cc lp pha di (Hnh 27A). Vi cc loi bao b nh thng g hoc st nha th khng cn thit (Hnh 27B).

A B

Hnh 27. Cch thc xp hng i vi st tre (A) v st g hoc st nha (B) trn phng tin vn chuyn

b. Gi cht cc thng hng trong mt khi m bo cho cc thng hng trong cng mt khi gi chng khng b trt ra khi khi trong sut qu trnh vn chuyn, iu c th dn ti s h hng ln. c. Cn che ph trnh ma, nng v gi to S dng vi bt che ph trnh ma t, phi sn phm di tri nng v di tri gi mnh trong qu trnh vn chuyn. Qu b m t s to iu kin thun li cho s pht trin ca vi khun v thi hng, cn vic phi nng s lm qu b nng ln. Phi by qu di tc gi cao dn n s mt hi nc v lm ho qu. d. Cn m bo s thng kh thch hp trnh hin tng nng cc b hoc s ym kh lm tng nhit v hm lng ethylen. Mt h thng thng kh nh v d Hnh 28 (Pantastico, 1980). Khi vn chuyn cn che ph cn thn bng vi bt v tm ngn gi c lm bng tm Gl phng t cao hn cabin.


Hnh 28. H thng thng kh trong xe ti khng lm lnh

e. Thao tc cn thn trong khi xp vo hoc ly ra Nu khng s d gy hng qu do va chm nh nt qu (Hnh 29).

Hnh 29. Nhng vt nt trn qu l biu hin ca s h hng do va chm hn ch thp nht vic lm ri qu trong sut qu trnh tin hnh v thao

tc, c th dng mt h thng bng ti nh hnh 30A (Pantastico, 1980). Bng ti gm 2 rng rc v mt si dy cho chc chn. Mt rng rc c t bn trong xe ti pha u thng xe, ci th hai t mt v tr di ng hoc ni c nh ca nh kho. Thng hng c th c treo trc tip hoc t vo trong mt ci r mc chuyn hng ln hoc xung xe ch hng. S dng thang hoc bc gip hot ng vn chuyn hng ln xung c d dng hn (Hnh 30B). Thang c th di chuyn c v mt thang lm bng g hoc st, chn thang lm bng st.

A


B

Hnh 30. H thng bng ti (A) v cu thang (B) gip bc v d hng thun tin

f. Thc hin vn chuyn vo thi gian mt trong ngy iu ny gip bo v qu khi s tng h hp v suy gim cht lng. g. Trnh nhng tr hon khng cn thit Nhng tr hon trong sut qu trnh vn chuyn tng mc hao tn cht lng qu. Tiu th

y l khu quan trng cui cng ca hot ng sau thu hoch gia ngi sn xut hoc ngi vn chuyn vi ngi mua hoc ngi tiu dng. Nhng hot ng x l th trng quyt nh cht lng cui cng ca sn phm by bn v cn cung cp cho ngi tiu dng cht lng tt nht c th. Sn phm phi c b ngoi hp dn, nh ti, khng b khuyt tt, cht lng cao. Cn c nhng x l thch hp, khng ch quan tm n ring sn phm m cn phi ch n thao tc ca ngi x l. hnh 31, v d, st y c chua chn c th c vn chuyn an ton hn bng xe y hoc xe ch hng chuyn dng.

Hnh 31. Vn chuyn cc st c chua bng tay ch


Mt s hot ng quan trng th trng (ngi bn bun v bn l) m bo cht lng v tnh thng phm ca c chua nh sau: 1. Thc hin v sinh thch hp Sn phm h hng phi c vt b, lm sch c s ng gi v bo qun, khu vc by bn phi c v sinh v lau dn sch s. C th s dng Chlorine 200ppm kh trng khu vc bn hng. 2. Ti lm sch Lau qu lm cho chng hp dn ngi tiu dng hn. Ra qu bng nc chlorin ha i vi nhng qu b h hng trong qu trnh vn chuyn. 3. Ti la chn, phn loi iu ny l cn thit i vi lot c chua c cht lng khng ng u, ln ln cc chn, b thng tn do bnh hoc do c hc. iu ny cng rt quan trng trong vic m bo tnh ng u v cht lng ca sn phm c by bn. 4. X l rm chn C chua c tiu th nhiu nht khi chn, do , c th dm chn c chua trc khi by bn. Vic x l chn cn tun theo quy nh ca a phng v phi c cng b rng ri. 5. Bao gi li - th trng bn bun, sn phm c la chn li v ng trong cc ti nh hn, ph hp hn vi phn phi l. 6. Trnh h hng do ethylene C chua rt nhy cm vi ethylene sinh ra bi s chn p. Mt khc, c chua chn cng sn sinh ra hm lng ln ethylene lm cho qu chn khng ng lc v lm gim gi tr ca nhng qu ti khc, v thng th trng bn bun v bn l thng bn cc loi qu khc nhau. Nhng sn phm sinh nhiu ethylen v nhng sn phm nhy cm vi ethylen khng nn chung trong mt phng hoc trn cng ngn by bn. Nhng ngun sinh ethylen khc (forklifts, phng lm chn, qu hng) phi c khng ch. S dng h thng thng hi v cht hp ph ethylen (nh KMnO4) lm gim lng ethylen trong khu vc bo qun. 7. Bo qun Tt c lng c chua nhn v khng th phn phi ht trong cng mt ngy, do cn phi bo qun. Phng bo qun vi ch bo qun ph hp l cn thit. Phi n s tng thch ca cc loi qu cng c bo qun. Ti liu tham kho Acedo, A.L. Jr. 1997a. Storage life of vegetables in simple evaporative coolers. Trop. Sci. 37:169-175. Acedo, A.L. Jr. 1997b. Ripening and disease control during evaporative cooling storage of tomato. Trop. Sci. 37:209-213. Acedo, A.L. Jr., F.G. Enriquez and M.A. Mante. 1994. Evaporative cooling storage of tomato and sweet pepper fruits harvested at different stages of ripeness. Proc. International Conference on Food Preservation and Security, Manila. pp. 213-218. Acedo, A.L. Jr., Acedo, J.Z., Galia, H.S., Gumop-as, M.A., Hinay, N.G., Parrenas, R.D., Miparanom, M.A., Sanaco, M.M. and Lorio, J. 2004. 1-MCP effects on Philippine horticultural produce. APEC Symposium on Quality Management in Postharvest Systems, Bangkok, Thailand, Aug 3-5, 2004.


Ait-Oubahou, A. 1991. Modified atmosphere packaging of tomato fruit. CIHEAM-Options Mediterraneennes. Bautista, O.K. and Acedo, A.L. Jr. 1987. Postharvest handling of fruits and vegetables. Manila, Philippines: National Bookstore. 27 pp. Batu, A. and Thompson, A.K. 1998. Effects of modified atmosphere packaging on postharvest qualities of pink tomatoes. Tr. J. Agric. For. 22:365-372. Beecher, G.R. 1998. Nutrient content of tomatoes and tomato products. Proc. Soc. Expl. Biol. Med. 218:98-100. FAO, 1986. Improvement of postharvest fruit and vegetable handling A manual. Bangkok, Thailand: Food and Agriculture Organization of the United Nations-Regional Office for Asia and the Pacific. Kader, A.A. Undated. Modified atmospheres during transport and storage of horticultural crops. PDF File. Ogawa, J.M. and Manji, B.T. 1984. In: Moline, H.E., ed., Postharvest Pathology of Fruits and Vegetables. University of California, Division of Agriculture and Natural Resources, UC Bulletin 1914. Opiyo, A.M. and Ying, T.J. 2005. Effect of 1-methylcyclopropene postharvest treatment on ripening process in cherry tomato fruit (Lycopersicon esculentum var. cerasiforme). J. Plant Physiol. Mol. Biol. 31:27-33. Pantastico, E.B. 1980. FAO/ENEP expert consultation on reduction of food losses in perishable products of plant origing. Working Document 2: Fruits and Vegetables. Rome: FAO, May 6-9, 1980. Redulla, C.A. et al., 1984. Temperature and relative humidity in two types of evaporative coolers. Postharv. Res. Notes 1:25-28. Reyes, M.U. 1988. Design concept and operation of ASEAN packinghouse equipment for fruits and vegetables. Laguna, Philippines: Postharvest Horticulture Training and Research Center and Southeast Asian Regional Center for Graduate Study and Research in Agriculture, UPLB. 56pp. Roy, S.K. 1989. Postharvest technology of vegetable crops in India. Ind. Hort. Jan-June:76-78. Sanchez, G. 2000. Postharvest hot water treatment for mangoes in Guatemala. Proc. Workshop on Postharv. Heat Trt., 22-24 March 2000, Israel. P. L17. Shellie, K.C. 2000. Citrus: Disinfestation heat treatments. Proc. Workshop on Postharv. Heat Trt., 22-24 March 2000, Israel. P. L5.


Smilanick, J. 2002. In: Kitinoja, L. and Kader, A.A., Small-scale Postharvest Handling Practices: A Manual for Horticultural Crops (4th ed)., UC-Davis, California. Suslow, T.V. and Cantwell, M. 2005. Tomato recommendations for maintaining postharvest quality. Postharvest Technology Research and Information Center, Department of Plant Sciences, University of California, Davis, CA, USA. 3 pp. Yaptenco, K.F., Masilungan, G.D. and Serrano, E.P. 2004. Bulk modified atmosphere storage of tomato. In: PHTRC Technologies, Postharvest Horticulture Training and Research Center, UPLB, Laguna, Philippines. ADB RETA 6208: Ti liu tp hun v Cng ngh sau thu hoch c chua v t cay. Page 31 of 69

B. T CAY Gii thiu chung

t cay (Capsicum annuum), l mt loi rau ph bin v c a thch trn khp th gii nh mu sc, hng, v, v gi tr dinh dng (Berke et al., 2004). Ngi ta tm ra rng v cay nng ca n l do capsaicin (8-methyl-N-vanillyl-6-nonenamide) v cc hp cht capscicinoid khc, nhng thc t n rt giu vitamin C v tin vitamin A, ngun ln ca hu ht cc vitamin nhm B, c bit l vitamin B6, v hm lng kali, magi, st ln. t cay c trng rng ri CLV v l mt phn khng th thiu trong mi ba n, c bit l Lo. N c n ti hoc s dng nh mt gia v ca nhiu mn n ti hoc chn khc nhau p ng nhu cu v v cay nng. N cng c ch bin thnh mt s sn phm nh t qu kh, t bt, hoc dng st. tng ngun cung cp t cay cho th trng hoc cho cng nghip ch bin th i hi khng ch ci tin ging v h thng sn xut, m cn phi c k thut sau thu hoch thch ng gim tn tht v ti a ha vic s dng sn phm. Ngc li vi c chua, pht trin cng ngh sau thu hoch i vi t vn cn hn ch.

Trong ln tp hun gn y nht, mt s khuyn co v cng ngh trong qu trnh qun l sau thu hoch t ti c tho lun. V vn thng tin cng ngh cng c a ra. Cc cng ngh ny v nhng khuyn co thc t c tho lun theo tng phn ca quy trnh sau thu hoch, v trong c mt vi cng on th cng.

Thu hoch v x l ti rung

chn thu hoch: t cay thng c thu hoch khi chn, nhng cng c th thu hoch khi cn xanh (Berke et al, 2004) (Hnh 1). trng thnh ca t xanh c th c xc nh da trn kch c, cng, v mu sc, nu qu chn tip sau thu hoch th cn t nht 50% mu c hnh thnh. (Aguilar, khng tm thy nm cng b).

Hnh 1: t thu hoch trng thi chn v xanh.

Cn lu rng t cay h hp khng t bin, t nht l sau thu hoch, v trong qu trnh chn trn cy n c th biu l kiu h hp t bin (Krajayklang et al, 2000). V vy, t c thu hoch khi cha chn s khng c kh nng chn tip hon ton, tr khi cung cp cc iu kin sau thu hoch thun li. Theo nghin cu ca Krajayklang et al (2000), loi t tiu ngt (t Hung) v t cayen c thu hoch


khi cn xanh hoc qu xanh s khng hon thin c mu di iu kin phng, trong khi qu c thu hoch ti thi im bt u chuyn trng thi v mu sc hoc sau th c th hnh thnh mu hon ton sau 7-9 ngy. Trong mt nghin cu v t chung c thu hoch thi im chn-xanh, qu c th hnh thnh mu m khi c tn tr di iu kin lm mt bay hi (Acedo, 1997).

Thi gian thu hoch: Qu trnh thu hoch c th ko di hng tun, tt nht l nn thu hoch vo bui sm trong ngy. Khng nn thu hoch trong hoc sau khi ma v iu kin m t s to thun li cho vi khun pht trin v y nhanh qu trnh h hng ca qu. Cng khng nn thu hoch khi tri nng, nu khng trnh c th khng nn ng gi ngay m nn xua nhit di bng rm.

Phng php thu hoch: t c hi bng tay (Hnh 2). Qu c tch khi cnh, v cn m bo rng cung qu cn c gi li nguyn vn. Ch thu hoch nhng qu t yu cu v mu sc v kch c, v nhng qu mm do qu chn cng c hi xung nhng s loi ra. Trong qu trnh thu hoch, ngi thu hi cn eo gng bo v tay v du (Capsaicin) trong qu c th gy bng gt. Ngi thu hi cn cn thn khng tip xc tay vi mt, mt. Qu c thu hoch c th trc tip trong cc thng nha ln trn cnh ng, hoc cho vo nhng x nha nh hn, ri sau chuyn vo thng ln. Cng c th la chn ti vi cotton ng t v sau chuyn sang thng ln.

Hnh 2: Thu hi t bng tay v ng trong dng c bng nha.

Khng nn thu hoch bng my mc i vi nhng qu dnh cho th trng dng theo kiu n ti, v c th gy ra nhng vt thng rng. Tuy nhin qu c thu hoch bng my mc c th c dng cho qu trnh ch bin.

Lu tr trn ng rung: Qu thu hoch khi cn trn ng rung th nn gi trong iu kin rm mt, bo v khi nh mt tri, gi ma. Nn dng thng nha vn chuyn t ng rung n nh bao gi ti thiu ha cc tn thng c gii. S dng bao ti hoc li s d gy tn thng.

Cc cng on trong nh ng gi

Lm sch: Tt nht l qu c lm sch ngay trn ng rung. Nu khng th c th lm sch bng cch c xt nh ly i cc mng bm bn v t ct. Nu qu trnh ra c tin hnh, nc ra cn phi sch hoc phi c v sinh bng


Clo (xem phn kim sot thi hng). Sau khi ra, qu phi c lm kh n mc thch hp trnh thi hng.

Phn loi/tuyn chn: Cha c tiu chun no la chn t. Nhng qu c xem l cht lng tt thng c hnh dng, kch thc, mu sc tng ng c trng cho tng ging. Nhng qu b khuyt tt nh b nt gy, thi hng, tn thng c hc v chy nng th nn loi ra. Nhng qu nh, nhn ho, hoc b cc vt lm, cng nh c nhng du hiu ca s mm ha th cng nn loi ra.

t c th phn loi theo mu sc nh , xanh, hoc hn hp , xanh v vng (c th cng nhau trong mt dng c cha nhng c ngn cch) v mi loi c th c xc nh bng mt ci tn ring (v d loi 1, 2, 3). Nhng yu t cht lng khc c th bao gm: - Khng dnh t ct bn. - Khng qu chn hoc mm - Khng nhim vi sinh vt hoc b cn trng ph hi - Khng c tn thng c gii, hoc nt gy - Cung cn xanh nguyn

Qu c phn loi bng tay trn thanh truyn ng hoc trn bn phn loi. Mt vi kiu bn phn loi n gin dng cho c chua c th chnh sa cho ph hp vi t. Cn phi c kinh nghim lm vic trong qu trnh vn chuyn, phn loi v tuyn chn qu.

Kim sot thi hng v cn trng hi: V sinh ng rung v phng trnh gy tn thng cho qu s gim c t l mc bnh. Ra trong dung dch Clo 300 ppm cng c th hn ch bnh (Aguilar), nhng sau phi lm kh n mc thch hp. Cng c cng b rng bi sp c thuc dit nm cng lm gim s thot hi nc v bnh nhng phng php x l ny khng nn dng v n c th li d lng thuc ha hc.

Cch x l khc an ton v n gin hn l ngm trong nc nng. Ngm t vo nc 53 550C trong 4 pht c th kim sot hiu qu s thi hng, v khng gy tn thng cho qu. X l nhit cng c th s dng kim sot cn trng hi, nhng iu ny cha c th li i vi s ph hoi ca su bore l mt loi su ph hi dai dng trong sut qu trnh tn tr qu kh. i vi xoi, ngm trong nc 460C trong 90 pht cho xoi to (500-700g) v 75 pht cho xoi nh (95%. Vic s dng cc cht lm mt bay hi cho mu m cng c th nghim nh gi.


Lm mt s b: Sau thu hoch, c th tin hnh lm mt s b xua nhit v lm chm qu trnh trao i cht ca qu. y cng l mt phn quan trng trong quy trnh lm lnh. i vi t c trng vng nhit i nh CLV, c th lm mt nhanh n 100C m cao, v nu im nhit thp hn c th gy ra tn thng lnh. Lm mt s b c th thng gi cng bc, lm mt bng bay hi, hoc lm mt trong iu kin chn khng. Lm mt bng bay hi l phng php n gin hn v r hn v so vi nhng phng php khc, nhng cn cn thn trnh thi hng do lm kh khng ng cch sau qu trnh x l.

Bao gi: t tiu cung cp cho th trng ni a c th s dng cc vt dng bao gi khc nhau, bao gm st tre, thng g, thng nha v ti do (nh 3). Thng nha tt hn so vi cc dng c khc trong vic bo v qu trnh cc vt thng vt l do c b mt nhn, chc chn v rng. Nu s dng st tre hoc thng g, cn phi c an ton tt, c th s dng vt lt (v d l ti, hoc bo c), v c dy buc c inh dng c cha. Cc r ng sn phm khng nn chng cht ln nhau, tr khi c tm chn cng gia cc lp. Ti do, ti li v bao ti nu s dng phi c t trong vt cha ln c tnh chc chn.

Hnh 3: ng t trong thng nha v ti do.

xut khu, tt nht nn ng t trong thng carton. Hai kch thc thng c s dng c kch thc 3 chiu bn trong l 20x51x34 cm, v 16x37.7x27.9 cm. Nu s dng thng ln hn, nn c tm chia km theo. Nu thng carton c thit k vi cc kp gi, th cn m bo rng chng khng gy vt thng cho qu.

Bo qun Nu s dng cc kho tn tr lnh, th t c th tn tr 100C vi m 85-

90% (Kitinoja v Kader 2004). Qu c th c gi trong 2 - 3 tun. Nu tn tr nhit thp hn 100C s gy tn thng lnh. Cc triu chng bao gm lm b mt, c cc vng sng nc, thi hng (c bit l ging Alternaria) v khng hnh thnh mu. Cc triu chng c th xut hin sau vi ny 00C, hoc vi tun 50C. nhy cm l khc nhau vi loi cy trng. Qu chn t b cm lnh hn so vi qu xanh. Khi tn tr trn 130C, qu s nhanh chn, v d nhim vi khun gy thi mc. Hn na, t rt nhy cm vi ethylene. Khi tn tr qu nn trnh cng nhng loi qu sinh ethylene v cc bung chn. Qu ang thi hng thng sinh ra lng ln ethylene, c th lm tng tc chn v h hng ca nhng qu khc, v


v th, cn kim tra trc loi b nhng qu h hng. Nn lm mt s b trc khi tn tr lnh.

Nhng ni khng c kho lnh, thng l nhng nc ang pht trin nh Lo, Vit Nam v Cambodia, nn phn loi, ng gi v tiu th qu trong 24 gi sau khi thu hoch. iu ny c bit quan trng i vi nhng ging cho sn phm c thi hn bo qun ngn. Cng c th la chn mt s phng php n gin gi qu ti lu.

Tn tr hoc bao gi trong iu kin khng kh ci bin (MA) c th s dng ko di tui th ca t (Kader). V d nh gi qu trong cc mng polymer, c bit l cc dng ch phm thng mi nh cc ti polyethylene, v polypropylene (nh 4).

nh 4: Ti cht do bao gi v bo qun trong iu kin kh quyn ci bin.

Trong mt nghin cu v t ca. Jinda, ngi ta nhn thy rng ti polyethylene dy c hiu qu hn so vi mng polypropylene v polyvinylclorua trong vic ko di tui th ca qu (Suwannasopon, 2004). Qu vn gi c hnh dng bn ngoi c th chp nhn c sau 28 ngy lu tr 100C.

Tn tr bng lm mt bay hi l phng php n gin v c kh nng s dng cho t, c bit l thun li cho s hnh thnh mu. Hiu qu trong vic ko di tui th v kch thch hnh thnh mu ca qu xanh thu hoch trng thi chn-xanh c chng minh t ngt (Acedo, 1997).

Vn chuyn v tiu th

t rt d b tn thng c gii, c bit l trong qu trnh vn chuyn c ng trong bao ti. Qu b tn thng c gii c biu hin nh b nt gy, thng, lm gim gi tr mt cch nhanh chng. Qu khng chuyn mu, d b thi hng do nhim bnh. Ngoi tr qu trnh x l chn, nhng khuyn co v lu tr khi vn chuyn v tiu th c chua c th p dng cho t ti.


Ti liu tham kho Acedo, A.L. Jr. 1997. Storage life of vegetables in simple evaporative coolers. Trop. Sci. 37:169-175. Aguilar, G.A.G. undated. Pepper. Centro de Investigacin en Alimentacin y Desarrollo, Hermosillo, Sonora, Mexico. Berke, T., Black, L.L., Talekar, N.S., Wang, J.F., Gniffke, P. and Morris, R. 2004. Suggested cultural practices for chili pepper. AVRDC Pub. #03-575. 8pp. Cantwell, M. 2005. Recommendations for maintaining postharvest quality of beel pepper. Postharvest Technology Research and Information Center, University of California, Davis, USA. PDF file. Kader, A.A. Undated. Modified atmospheres during transport and storage of horticultural crops. PDF File. Kitinoja, L. and Kader, A.A. 2004. Small-scale postharvest handling practices: A manual for horticultural crops. 4th ed. University of California-Davis, California, USA. Krajayklang, M., Klieber, A. and Dry, P.R. 2000. Colour at harvest and post-harvest behaviour influence paprika and chilli spice quality. Postharv. Biol. Technol. 20(3):269-278. Sanchez, G. 2000. Postharvest hot water treatment for mangoes in Guatemala. Proc. Workshop on Postharv. Heat Trt., 22-24 March 2000, Israel. P. L17. Shellie, K.C. 2000. Citrus: Disinfestation heat treatments. Proc. Workshop on Postharv. Heat Trt., 22-24 March 2000, Israel. P. L5. Suwannasopon, P. 2004. Modified atmosphere packaging of chilli. Kasetsart University, Bangkok. BS Thesis.


C. K THUT SY T V C CHUA Gii thiu

t kh l mt nguyn liu ph bin v quan trng ca cc nc c truyn thng thch gia v v c s dng trong vic chun b n cng nh tng v hp dn ca thc phm k c mt s hp. Ngoi ra, c chua sy c xem l mt loi sn phm c gi tr cao. Nu c sy tt, c chua s gi c mi v c trng nh ca c chua ti khi c hon nguyn.

Sy l mt trong cc phng php ch bin v bo qun nng sn c in v n gin nht v khng yu cu cc thit b c bit nh l cc phng php khc nh ng hp hay lmf lnh (UIUC, 1984). Qu trnh sy bao gm vic lm thot bt hi m t sn phm lm cho chng c kh nng bo qun lu hn. Cc sn phm sy c mi v hp dn, gi tr dinh dng cao, c khi lng nh, d chun b v d s dng (Whitfield, 2000; Makeni et al., 2001). Nng lng tiu hao cn thit thp hn so vi cc phng php ch bin khc (chng hn hp hay lm lnh) v din tch kho t hn so vi cc hp hay l cc thng bo qun lnh.S hao tn gi tr dinh dng ca cc sn phm sy l thp nht so vi cc cc sn phm ch bin khc.Vitamin A s c duy tr trong qu trnh sy. Tuy nhin, do vitamin A rt nhy cm vi nh sng nn duy tr vitamin A, cc sn phm sy cn c ng trong cc loi bao b sm mu.Vitamin C s b tiu hy trong qu trnh sy do tip xc vi nhit cao, tuy nhin c th hn ch bng cch x l lu hunh. Cc sn phm sy c hm lng cht x v Carbonhydrates cao, t cht bo v th nn c ngitiu dng a chung. Cc sn phm sy rt d vn chuyn v c gi thnh vn chuyn thp v d bo qun chnh v th nn gip cho nh nng ch ng trong vic tiu th sn phm vo thi im thch hp m h mun. V l cc sn phm sy tng cng an ninh lng thc qui m h gia nh, to thm cnng n vic lm v ngun thu nhp n nh.

Ti liu k thut ny tp trung ch yu vo cc k thut sy n gin, gi thnh thp, c bit l k thut sy s dng nng lng mt tri.Cc thng tin v c chua v t c tng hp ng thi di cng mt ch v mt s k thut sy (v d sy bng nh nng mt tri) c th c s dng cho c hai i tng. Cc im khc bit c th s c lm r. X l nguyn liu trc khi sy

Chun b nguyn liu: m bo cht l ng ca sn phm sy, nguyn liu phi c x l v a vo sy cng sm cng tt sau khi thu hoch (UIUC, 1984).C chua phi chc, chn c trng. t sy phi c thu hoch khi t chn ti a, tt nht l khi kh mt phn trn cy. t chn mng c mu sc cha pht trin hon ton. Trong nghin cu ca Krjayklang v cng s (2000), i vi t ging cayenne khi thu hoch m cha c mu m th sn phm sy u c cng mu thp. i vi ging t ca g (Paprika), hu nh khng c s khc nhau v mu sc ca sn phm ca t nguyn liu chn mng v t nguyn liu thu hoch khi kh mt phn trn cy, tuy nhin t nguyn liu chn mt phn trn cy c cng mu nhnh hn.

Sau khi thu hoch, qu c chn v ra sch. Loi b cc qu b bm gip, qu chn, thi. mt qu thi c th nh hng v mi trong c mt m sy. tt sy


khng cn phi thi lt, tuy nhin vic loi b cung qu cng c tc dng rt ngn thi gian sy (Berke et al., 2004). Trong mt s trng hp, khi sy t cng c th thi lt rt ngn thi gian sy v ci thin mu sc v mi v ca sn phm (Aguilar, undated). C th loi b ht bng cch sng hoc phun nc. Mt khc, c chua sy thng c b i theo chiu dc loi b mt phn nc v ht. Cc na qu ny au li c tip tc ct thnh lt theo chiu dc vi dy 6-8mm trc khi a vo sy. Cc x l trong ch bin nh chn, lu hunh c th c s dng nh mt s c s vn thng lm, tuy nhin i vi c chau cc bin php x l ny c l khng cn thit v cc cht mu ca c chua (carrotene) rt chu nhit v n nh. Thay vo c th x l bng cch nhng trong dung dch Kali bisulphite 0.7% v 10% mui n.

Gi gn v sinh trong qu trnh chun b v qu trnh sy l rt quan trng. X l bng lu hunh: l mt bin php x l chng xy ha rt hu hiu

duy tr mu sc ca sn phm (UIUC, 1984). Ngoi ra, x l lu hunh cng c tc dng duy tr cc vi tamin A v vitamin C v hn ch mt s cn trng v vi sinh vt ph hi hy thi hng sn phm. Lu hunh c th gy d ng. Lu hunh khi kt hp vi nc trong ngiun liu sy s to thnh a xt sulphur, tuy nhin a xt ny s b bay hi trong qu trnh sy nn khng nh hng n ngi tiu dng.

Nguyn liu cn phi c x l lu hunh ngay sau khi c chun b. Qu trnh x l ny c th c thc hin bng cch xng khi lu hunh hoc nhng trong cc dung dch sulphite. X l bng khi lu hunh (thu c khi t bt lu hunh) c tc dng cao hn nhiu so vi nhng trong cc duch dch sulphite, nhng bin php ny yu cu thi gian v thit b b sung. Cc hp g hoc thng carton v cc khay g c y bng vi tha s c s dng. Vic x l xng lu hunh v sy cc sn phm c x l lu hunh phi c thc hin ni thng thong bi v kh sulphur c mi kh chu v gy chy nc mt, nc mi. X l bng cch nhng trong dung dch sulphur n gin hn nhng hiu qu thp hn, ngoi ra do nguyn liu b ngm nc nn thi gian sy s di hn. X l bng cch nhng trong dung dch Natri bisulphite vi nng 1-2 tha trong 1 gallon (4.5 lt) trong thi gian 5-10 pht thng c s dng. Nguyn liu sau x l c lm kh bng cch trn khn thm nc.

Chn: l qu trnh nhng nguyn liu trong nc nng trong mt thi gian ngn nhm c ch hot ng ca cc enzyme gy bin mu v mi ca sn phm trong qu trnh sy v bo qun, ph v lp v cng v sp ca nguyn liu lm cho nc thot ra d dng hn do gim thi gian sy (UIUC, 1984; Berke et al., 2004). Ngoi ra, chn cn c tc dng tiu dit mt s vi khun v con trng gy hi. Nu chn bng nc si th thi gian chn thng thng khong 30-50 giy, nguyn liu ngay sau khi chn phi c lm mt trong nc lnh (UIUC, 1984). Chn c th c tin hnh nhit thp hn (65oC), nhng thi gian chn s di hn, khong 3 pht (Berke et al., 2004). Hn na, chn ch nn nhm mc ch lm mm v hn l s dng cc dung dung dch xt nh dung dch kim (0.5-3%) v cc yu t c hi khi s dng (UIUC, 1984). Ni chung, chn c hiu qu thp hn so vi s dng lu hunh trong vic duy tr mu sc ca sn phm.


Cc ch sy Nhit sy khng c qu cao n mc lm chn sn phm. Nhit sy

ph hp, c bit i vi t, nm trong khong t 60-650C, nhng c th s dng nhit cao hn sy sn phm thi im ban u khi hm lng m cn cao (http://www.chilemasters.com/index.html). Tuy nhin, trong phng php phi nng, hoc sy kh bng nng lng mt tri, rt t khi t c khong nhit ny. Khay sy c th c lm t cc tm thp khng r, hoc t cc mnh g mng. Khng nn lm bng nhm, v n s phn ng vi axit trong qu. Kim loi c m in, ng, si thy tinh, hoc cc tm vinyl cng khng dng c.

Sn phm nn c sy kh nhanh, nhng khng c nhanh n mc khin cho lp v b kh cng trc khi m bn trong vn chuyn ra b mt bay hi. Qu trnh sy khng c b gin on trong thi gian di. Nm mc v sinh vt gy thi hng c th pht trin trn mt b phn sn phm sy kh.

t c lm kh xung m 8-12%. T s gia trng lng qu ti v sn phm sy l khong 5:1. Trong khi , c chua cn sy n khi t s ny l khong 25:1. Trung bnh, c sy 1 kg c chua ti th c 40 g sn phm kh. Phi nng

Phi nng l phng php sy n gin nht v kinh t nht. Sn phm c trn khay sy hoc ln mt tm ph trn mt t (trn chiu, hoc trn tm nha), v phi di nh nng mt tri. Mt cng ty thng mi ln ang sn xut sn phm c chua sy cht lng cao bng phng php phi nng p dng GAP v HACCP (hnh 1A) (http://www.valleysun.com/recipe/php). Quy trnh bt u bng 12 gi xng kh SO2 gi mu sc v hng v, ngn cn sinh vt gm nhm, cn trng v cc loi chim n qu. Trc khi sy, qu c chun b theo mt quy trnh, t phn loi tuyn chn, loi b ht, n ri ra khay sy. Di iu kin ca phng php phi nng truyn thng, mc d sn phm thng c cht lng km v khng v sinh, khng trnh c bi, ma gi, cng nh cn trng, cc loi chim v loi gm nhm (hnh 1B), nhng c th khc phc iu ny bng cch che ph ln sn phm mt lp vi th hoc vi mn. Qu trnh thng din ra chm, c bit l trong cc vng nhit i m, ma nhiu, v nhiu sng, qu thng d b thi mc (Berke v cng s, 2004). V vy, vic b sung cc phng tin thun li cho vic sy kh, nh my sy dng nng lng mt tri hoc my tch nc, v t nng nhn to l iu cn thit.

nh 1. H thng sy bng phi nng qui m ln (tri) v qui m nh (phi)


My sy dng nng lng mt tri My sy dng nng lng mt tri l thit b c bit kim sot qu trnh

sy v bo v sn phm khi b tn thng bi cn trng hi, bi bn, ma gi v cc yu t khc (http://igadrhep.energyprojects.net/Links/Profiles/SolarDryers/Techprofile.htm). So vi phng php phi nng, my sy dng nng lng mt tri sinh nhit cao hn v c m tng i thp hn, tng tc chuyn ng ca khng kh qua sn phm, dn n thi gian sy ngn hn, m sn phm thp hn, v gim h hng trong qu trnh sy. My sy dng nng lng mt tri c rt nhiu kiu dng cu to. Nguyn tc c bn l khng kh c lm nng ln trong b thu nng lng bng hiu ng nh knh. Khng kh nng sy kh sn phm trong mt bung sy. Ty thuc vo cu trc, c b thu v bung sy c th kt hp hoc ring ri nhau.

Sy bng nng lng mt tri khng n gin l mt phng php dng nng lng mt tri thay th cht t (http://igadrhep.energyprojects.net/Link/Profiles/SolarDryers/TechProfile.htm). N l mt quy trnh k thut to ra vt liu kh theo yu cu cht lng thay th s dng cht t. La chn kiu my sy dng nng lng mt tri ph hp vi mc ch cn phi quan tm n (1) kiu sn phm a vo sy, la chn thi gian thu hoch, v c th x l s b, (2) s lng v cht lng sn phm, (3) s bin i v bc x mt tri theo ma, (4) quy trnh v thi gian biu cho qu trnh sy, v (5) chi ph u t.

Trong ti liu ca Kitinoja v Kader (2004), s phn loi my sy dng nng lng mt tri ca Fuller (1993) c tng kt, bao gm t sy trc tip, t sy gin tip, kiu kt hp, kiu ng, kiu ng thp, v my sy dng lu, dng thng. Di y l mt cch phn loi my sy dng nng lng mt tri khc, k n c phng php phi kh (http://igadrhep.energyprojects.net/Links/Profiles/SolarDryers/TechProfile.htm):

1. Sy kh truyn thng bng khng kh thong (phi kh) Sn phm c phi thong di nh mt tri, gi, v cc yu t khc.

2. My sy dng nng lng mt tri trc tip (t sy-hnh 2) Cu trc c c lp bn trong va l b thu nng lng mt tri, va l ni din ra qu trnh sy. Nhit bc x c thu li trong bung sy (c thng gi) qua mt lp v trong (bng nha hoc knh). Khay ng sn phm sy c t bn trong bung sy.


nh 2. Sy trc tip bng nng lng mt tri kiu bung (tri) v kiu hp (phi)

3. My sy dng nng lng mt tri gin tip (thermosyphon dryers-hnh 3)

Cc my sy loi ny c mt b thu nhit mt tri v mt bung sy ri, c th kt hp li hoc tch ri nhau ra. Chng hot ng hiu qu hn v cho php kim sot qu trnh sy tt hn. B thu lm nng khng kh, sau khng kh bc ln do i lu, p n i qua cc khay sn phm ang sy trong bung sy. i vi nhng thit b sy ny, c th tng tc chuyn ng ca dng khng kh, hoc khng. Kiu my sy ny ph hp nht i vi qu trnh sy quy m thng mi a li gi tr cao.

Hnh 3. Sy bng nng lng mt tri kiu gin tip vi b thu nng lng ring

Cc my sy n gin khc hot ng theo phng thc n gin, nh bung sy c d phng (v d bao ngoi thit b bng cc tm nha hoc knh) tng thm nhit bn trong b thu nng lng (hnh 4). Hn na, c th kt hp my sy nng lng mt tri vi ngun nhit nhn to.


Hnh 4. My sy bng nng lng mt tri kiu hn hp

Cc loi my sy chi ph thp di y c th xp vo kiu my sy trc tip

hoc gin tip, hoc kiu kt hp.

My sy dng nng lng mt tri n gin bng lu nha Mt my sy n gin c th c lm bng g hoc tre vi mi nha trong

v mt ci bn c ph nha ti mu nh minh ha trong hnh 5. Kiu thit k ny l tng ca chng trnh an ton thc phm Malawi (http://sparknet.info/home.php) v c s dng sy rt nhiu loi nng sn bao gm c t v c chua.

nh 5. My sy n gin dng nng lng mt tri vi cc tm ph bng plastic

My sy dng nng lng mt tri kiu hp

Loi my ny c lm t cc khay bng li thp hoc cc vt liu khc gi sn phm trn mt khung g hoc khung bng vt liu khc, c bao quanh bi mt tm nha trong c th l polyethylene - PE (dy hoc mng), polyvinylchorit (PVC), hoc cc mng do (nh 6). Ngi ta ch to ra rt nhiu kiu my sy khc nhau dng ny, nh c minh ha trong hnh 7.


nh 6. My sy nng lng mt tri n gin kiu hp c vch bng cc tm nha

nh 7. My sy nng lng mt tri kiu hp c gc nging thay i (Mwithiga v

Kigo, 2006)

My sy minh ha trong nh 7A bao gm mt tm hp th bng thp dy 20

mm, c lm thnh hp khng np kch thc 1,0 x 0,8 x 0,3 m. B mt bn trong c sn mu en ti a kh nng hp th bc x mt tri, trong khi mt ngoi c sn mu trng. Mt y ca tm hp th c cch nhit bng tm vn dy 15 mm, trong khi cc mt bn th khng c cch nhit. Khng gian bn trong hp (bung sy) c chia thnh 4 ngn thng ng c kch thc bng nhau dc theo chiu di ca hp, vch ngn l cc li thp. Khay sy cng c lm bng li thp 5 cm, t trn y tm hp th. Pha trn nc bung sy c che ph bng tm polyvinylclorit trong, dy khong 20 micromet. Tm ny c c nh trn khung g sao cho va kht to thnh np ca bung sy, v cho php d dng m ra khi xp hoc d sn phm. khng kh lnh i vo bung sy qua cc l khoan 3 mm di y hp, v thot ra bng khe h rng 5 mm np i din, c th nhn thy trong hnh minh ha 7B. Khng kh chuyn ng bng i lu t nhin.


My sy dng nng lng mt tri c nhiu khay sy y l cc my sy trc tip bng nng lng mt tri kiu lu thng t

nhin vi cc khay sy kiu bc thang, c che ph bng cc tm nha do (nh 8, 9).

nh 8 (tri) l mt my sy mini c 3 khay sy (55,5 x 15,3 x 3 cm), v khng kh i vo t y thit b, v qua tt c cc khay trc khi thot ra ngoi t pha trn nc thit b (Kaur v cng s, 2005). Vt liu c s dng xy dng l loi knh ca s dy 4 mm, cc tm thp nh, v st. C th che ph cc khay sy bng cc tm che chn bao quanh (56 x 15,8 x 2 cm), v qu trnh sy c th thc hin c khi khay c che ph, hoc c m thong. Kch thc ca ton b my sy l 64,4 x 27,2 x 54,4 cm, v nghing mt gc 450 so vi phng ngang. nh 8 (phi) cng l my sy dng nng lng mt tri c nhiu khay sy, c din tch mt thong l 1 m2. n c 5 khay c khoan l (101 x 18,5 x 3,5 cm) c sp xp thnh cc bc khc nhau trn khung g. Khng kh i vo t y thit b, v i ra pha trn sau khi i qua tt c cc khay. Vt liu c s dng khung l st (2,54 x 2,54 x 0,32 cm). My sy (190 x 130 x 117,2 cm) nghing 450 so vi mt ngang, v loi knh ca s dy 4 mm c s dng hp th nng lng mt tri.

nh 8. Thit b sy nng lng mt tri mini nhiu khay (Kaur v CS, 2005)

nh 9. My sy nng lng mt tri nhiu khay di ng (Singh v CS, 2004)


nh 9 l my sy dng nng lng mt tri kiu khung c th di chuyn c, vi np bng knh c th nhc ra c. Khng kh i vo t bn di y thit b, qua cc khay sy ri thot ra t pha trn nh (Singh v cng s, 2004). N c cu to gm mt khung gi cc khay (kch thc 1,35 m2), v mt tm knh c th nhc ra c, t lm np. N c hai on kt thc ca khung c lm bng cc ng bo v, ng knh 17 mm, v 18 ng khc c ng knh bn ngoi 16 mm c hn vi cc ng ni trn. Cc ng ny to thnh 7 cp 7 nc thang khc nhau v mi cp c tnh l 1 khay. Tm knh trn cng c mt khung kch c 194 cm x 189 cm (phn din tch c khe h l 188 cm x 183 cm) c lm t cc ng bo v ng knh 17 mm v c gn vi cc tm nha chu tia cc tm. My sy dng nng lng mt tri kiu nh knh

Cc loi my sy ny l loi my sy nng sn bng nh knh lu thng t nhin, cu to chnh gm mt khung c lm t cc thanh kim loi c trng mu en, li bng nha chng mn, v mt b mt hp ph bc x c trng mu en (nh 10) (Koyuncu, 2006). Khung my c che ph bng cc tm polyethylene sch tt c cc mt. Tm ph cho mt sau ca khung phi c b tr cho php a sn phm m vo bung sy v ly sn phm sy kh ra. Cc tm nha che ph y mt trc v mt sau cng cn b tr khng kh c th lu thng vo trong bung sy, trong khi cc l thong pha trn cng ca khung li ng vai tr l li ra cho khng kh m. Loi my sy ny c hiu qu gp 2-5 ln so vi vic sy bng khng kh thong. Thit k mt ng khi s gip tng cng hiu qu hot ng ca my sy.

nh 10. Cc l sy kiu nh knh (Koyuncu, 2006)

My sy dng nng lng mt tri v nng lng sinh khi Kiu my ny s dng c nhit mt tri v nhit t l kh sinh khi sy

(nh 11). N thc s thch hp s dng nhng vng m thi tit khng d bo c, hoc trong sut ma ma.


nh 11. My sy hn hp nng lng mt tri sinh khi (tri) v kt cu bn trong

(phi) (Prasad v Vijay, 2005)

My sy dng nng lng mt tri quy m ln Cc loi my sy ni trn thng ch hot ng trong phm vi nh. i vi

qu trnh sy quy m ln, ngi ta s dng my sy dng nng lng mt tri c m t trong nh 12 (Gniffke, 2006). N hot ng trn mt nguyn tc hn hp v bung sy c s d phng tng nhit bn trong.

nh 12. My sy nng lng mt tri cng sut ln (Mali)


My sy AIT Vin cng ngh Chu ti Thi Lan (AIT) qua chng trnh Cng ngh

nng lng khu vc chu ch to ra mt lot cc loi my sy n gin dng nng lng mt tri chi ph thp, mt vi trong s c cng b nh l s qung b cng ngh (nh 13-17) (Kumar v Bhattacharya, 2005). Mt s kiu my sy khc phc tp hn v chi ph cao hn cng c thit k, nh kiu ng, nhng khng c gii thiu y.

nh 13. My sy nng lng mt tri kiu hp

nh 14. My sy nng lng mt tri kiu hp c ci tin


Hnh 15. My sy nng lng mt tri kiu bung (A) v mu c ci tin (B)

nh 16. My sy hn hp FD-50 c b phn thu nhit v b phn s dng nng lng sinh khi (1- Bung sy, 2- B phn thu nhit mt tri, 3- L t nng lng sinh khi,


nh 17. H thng sy hn hp nng lng mt tri nng lng sinh khi (1- Bung sy, 2- B phn thu nng lng mt tri, 3- B phn t nng lng sinh khi)

My sy dng cc nc trong d n RETA 6208 Mt vi kiu my sy c kim nghim trong d n RETA 6208 c minh

ha di y. My sy dng nng lng mt tri ca trng i hc Nng nghip Hong Gia, Phnom Penh, Campuchia, l kiu hot ng kt hp (hnh 18A). B thu nng lng (phn trn) v bung sy c khung nhm c bao ph bng tm nha. My sy c bnh li di chuyn d dng. Bung sy c cung cp turbin quay bng nng lng gi thot kh. Nhit bung sy thng nm trong khong 55-600C trong nhng ngy nng.

nh 18. Thit b sy nng lng mt tri i hc nng nghip Hong gia Cambodia

(A) v i hc tng hp Lo (B).


Tng t, my sy dng nng lng mt tri ca khoa k thut, trng i hc Quc Gia Lo, Vienchn, Lo (my sy NUL) cng hot ng theo li kt hp (hnh 18B). Phn trn nh ca b thu nng lng c lm bng thy tinh vi b mt pha trong l mu en v c lm nhn li trong khi bung sy c che ph bi tm GI trn, sn en, v c cung cp mt ng khi thot kh. B thu nng lng c th c tch ring ra khi bung sy. My sy c s dng trong mi iu kin thi tit, v c th ngoi tri ngay c khi ma gi. Hai loi my sy dng nng lng mt tri ny s c s dng th nghim sy t.

Vit Nam, i RIFAV s th nghim sy c chua bng my sy ci tin SN-300 dng nng lng than .

nh 19. Thit b sy SN-300 c ci thin (Vin Sau thu hoch Vit Nam)

Cc hot ng sau khi sy Sau khi sy, t c bao gi cht trong bao ti trng lng >200 Ib (91 kg)

v c tn tr trong kho thng (khng lm lnh) trong khong 6 thng (Aguilar, khng tm thy nm xut bn). cc nc Cambodia, Lo v Vit Nam, vic s dng cc ti polyethylene l ph bin (nh 20).


nh 20. ng t kh vo ti PE

S ph hoi ca cn trng l vn chnh trong qu trnh tn tr t kh kho tn tr thng. kim sot hot ng ca cn trng, v lm chm qu trnh mt mu , nn tn tr 0-100C vi m tng i l 60-70% (Aguilar, khng bit nm xut bn). Hm lng m ca t trong sut thi gian bo qun nn thp (10-15%) trnh s sinh trng ca nm mc. Vi hm lng m cao, sn phm s tr nn qu mm, khng xay c, v c th phi sy li. Vi hm lng m rt thp (

Gniffke, P.2006. Pepper trials-d n RETA 6208. Bo co tin d n RETA 6208 trong hi tho k hoch hng nm, 25-26/5/2006, PhnomPenh, Campuchia. Kaur, P., Kumar, A., Arora, S. v Ghuman, B.S. 2005. Quality of dried coriander leaves as affected by pretreatments and method of drying. Eur Food Res Technol Kitinoja, L. v Kader, A.A. 2004. Small-scale posharvest handling practices: s tay cho vic thu hoch cc sn phm cy trng. Phin bn 4. Trng i hc California-Davis, California, M. Koyuncu, T. 2006. An Investigation on the performance Improvement of geenhouse-type agriculture dryers. Renewable Energy 31: 1055-1071. Krajayklang, M., Klieber, A. v Dry, P.R. 2000. Colour at harvest and post-harvest behaviour influence paprika and chilli spice quality. Postharv. Biol. Technol. 20(3): 269-278. Kumar, S.v Bhattacharya, S.C. 2005. Technology packages: Solar, biomass and hybrid dryers. Bangkok, Thi Lan: Trung tm thng tin t liu nng lng khu vc (RERIC), Vin cng ngh chu . Ti liu PDF. Makeni, A.P., Soundy, P. v Brutsch, M.O. 2001. Solar drying of fruit and vegetables. S nng nghip, Pretoria, Nam Phi. Mwithiga, G. v Kigo, S.N. 2006. Performance of a solar dryer with limited sun tracking capability. J. Food Engg 74: 247-252. Prasad, J. v Vijay, V.K. 2005. Experimental studies on drying of Zingiber officinale, Curmuma longa I. v Tinospora cordifolia in solar-biomass hybrid drier. Renewable Energy 30: 2097-2109. Singh, S., Singh, P.P v Dhaliwal, S.S.2004. Multi-shelf portable solar dryer Renewable Energy 29: 753-765. UIIC. 1984. Drying food. University of ILLinois at Urbana-Champaign (UIUC), trng thng tin dch v v m rng hp tc x nng nghip 1227. Whitfield, D.E. 2000. Solar dryer systems and the internet: important resources to improve food preperation. Paper presented in Intl. Solar Cooking, 26-29 thng 11/2000, Kimberly, Nam Phi. http://sparknet.info/home.php. Construction and use of a simple solar drier to preserve food for off-season. http://www.valleysun.com/recipe.php. Drying (Valleysun) http://igadrhep.energyprojects.net/Links/Profiles/SolarDryers/TechProfile.htm. Solar dryers. http://www.chilemasters.com/index.html. Drying chile peppers.


THC HNH 1. Chun b cc khay t em phi nng v chun b cc iu kin ca my

sy dng nng lng mt tri NUL. 2. Kim tra s ghi ca thit b o nhit v m trc khi s dng 3. Cn qu so snh vi trng lung trc khi sy 4. Tnh hao ht khi lng ( nhc n trong bui tp hun trc) 5. nh gi cc thng s khc nh cng mu, s i mu v mc thi

hng. Tho lun kt qu v cc yu t lin quan khi s dng my sy dng nng lng mt tri.


D. K THUT CH BIN PASTE V PUREE C CHUA Gii thiu C chua l loi rau ch o nhiu nc bao gm c Vit Nam, Lo, Campuchia. C chua c tiu th dng n ti v ch bin. Trong sut thi gian chnh v, lng c chua cung cp ra th trng l rt nhiu v gi thp hn nhiu so vi thi k tri v.

Ch bin rau l mt gii php mi cho nng dn v th trng c chua v gi c ca c chua ti rt bin ng. Sn phm ti c thi gian bo qun ngn v nu ngi nng dn c th ch bin th s thu nhp ca h c th tng nh s phong ph ca sn phm. V li, ch bin rau c th gim lng hng nhp khu v nu sn phm t cht lng tt th c nhiu kh nng xut khu. Th trng xut khu c th kch thch cc hot ng sn xut nng nghip. T c th to nn nhiu c hi vic lm c bit cho nn kinh t cc khu vc nng thn.

C nhiu phng php ch bin c chua khc nhau. Trong ti liu ny, nu cch ch bin paste v puree c chua bng cc k thut n gin v gi r ph hp vi iu kin thit b v ngun lc ca nng dn, ngi ch bin v cc nh sn xut quy m nh - i tng chnh ca RETA 6208. Ch bin Paste c chua

Hnh 1 trnh by s quy trnh ch bin c chua bng phng php n gin.

Nguyn liu. C chua c cht lng cao nht (chn , mm) v khng b h hi (h hng do cn trng hoc bnh, cc tn thng vt l), nn cn chn la.

Paste c chua l dng c chua c c cha 24% cht kh t nhin hoc cht kh ha tan t 24oBx(c xc nh bng my o kh). Puree c chua cng l c chua c c nhng gii hn hm lng cht kh ha tan c th thp hn t 8% n 24%. cc khu vc nng thn, ni khng c thit b o kh, th c th xc nh bng kinh nghim da vo dnh ca sn phm. Chng hn, vi im dng l 24oBx, th paste/puree c chua s dnh cht trn tha v chy chm trn t giy.

Nu s dng c chua cha chn, th sn phm s khng c mu nh mong mun hoc c v ng do s dng c chua xanh. C th s dng cc ging c chua khc nhau, nhng nhng ging c kch thc qu ln l tt hn c v chng d loi v v b ht. Nguyn liu phi c ra di vi nc sch. Ra c chua loi b cht bn v nhng tp nhim trn b mt nh vi sinh vt, tn d thuc tr su v kim loi nng.

Chn v gt v. Chn l mt khu quan trng trong ch bin rau lm mm v gip vic gt v c d dng v c ch hot ng ca cc emzym, c bit l catalaze v cc enzym oxi ha peroxidase, nguyn nhn ca s bin mu v hng. Khu ny cn thc hin ng nhit v thi gian. Qu c chn trong nc si khong 5-10pht. Sau lm ngui bng nc lnh trong 5-10 pht. S dng dao hoc cc vt dng n gin bc v.


Loi ht v nghin. B i qu v dng tha con loi ht. Ht c th lm sn phm c v ng. Sau khi loi ht, cc phn b i ca qu c ct thnh cc ming nh cho vo my xay. Nu khng c my xay c th dng dao bm nh, tuy nhin s dng cc my xay hoc my ch th s d dng hn v cn lm gim thi gian un nu. Mt cch lm khc cho nhng ngi nng dn v cc nh ch bin cc vng nng thn, s dng chy v ci gi nt c chua. Sn phm sau khi xay nghin c lc qua li st khng g ly dch v loi ht v nhng mnh v cn st li.

C c hoc un nu. Bc ny c thc hin khong vi gi ng h n khi bay hi lng nc sn phm c c c mu m, l paste v cng l sn phm cui cng. c tnh yu cu ca sn phm cui cng l c mu v cc cht lng cm quan tt (hng v v tt).

Khi un, t ni cha y dch qu xay ln bp. Khuy u v lin tc bng mt tha g trnh chy. Khi dch qu t 10oBx, thm vo 2% mui v tip tc un n 24oBx. Thi gian nu khong 2-3 ting la nh v va. Sau nhc ni ra khi bp. Trong mi trng axit, pectin c th to gel v nu sn phm paste c chua cn trng thi gel th c th thm vo 1% pectin v c chua cha t pectin. Pectin cng c th lm gim thi gian un nu.

Thanh trng hoc kh trng. Khu x l ny ph hy cc enzym trong rau nh vi khun v nm. Qu trnh ny thc hin bng cch un cc l thy tinh trong ni nc si trong 20 pht. Khi l vn cn nng, rt sn phm paste vo, y kn v cho vo nc nng. Nhit ca l cha sn phm v nhit ca nc phi gn nhau trnh v l. Nc phi ngp l t nht khong trn 2 ngn tay. Thi gian gi si nc tnh tnh t khi bt u si ph thuc vo sn phm v kch c l. Sau khi thanh trng, l sn phm c lm ngui khong 2 gi.


Lc

Tch ht, nghin

Chn v bc v

Ra sch

Phn loi, tuyn chn

Thm 2% mui (v 1% pectin hoc agar)

C c hn hp nc qu - tht qu

ng chai v ghp np

Thanh trng Lm ngui

Bo qun

Thu hoch

Hnh 1: S quy trnh ch bin paste c chua n gin


Ch bin Puree c chua

S hnh 2 l quy trnh ch bin sn phm puree c chua. Qu trnh ch bin tng t nh sn phm paste c chua ngoi tr khu un nu (gia nhit). Sn phm ny yu cu kh ti thiu l 8oBx v ti a l 24oBx. Khi dch qu t 8oBx, cho thm 1% mui (2% vi paste c chua) v tip tc un n khi t 24oBx. Thi gian un khong 1 ting vi la nh v va. Nhng khu khc tin hnh ging nh ch bin sn phm paste.

Hnh 2: S quy trnh ch bin puree c chua n gin

Lc

Tch ht, nghin

Chn v bc v

Ra sch

Phn loi, tuyn chn

Mui 1% C c, 8-24% MS

ng chai v ghp np

Thanh trng Lm ngui

Bo qun

Thu hoch


Thc hnh K thut ch bin paste c chua n gin1. Chun b 5-10 kg c chua chn v ra trong bn hoc chu nc sch . 2. Chn qu trong nc si khong 5-10 pht v sau lm ngui bng nc trong 5-10 pht. 3. Dng dao gt v qu, ct nh v loi ht bng tha. 4. Xay tht qu bng my xay, my ch hoc chy v ci. 5. Lc tht qu nghin qua mt ci ry lm bng thp khng g ly dch qu. 6. t ni cha dch qu ln bp, nh la v c c n 10oBx. 7. Cho thm 2% mui v 1% pectin 8. Trong qu trnh un, dng mt tha g khuy u khi dch qu n khi kh t 24oBx, c th kim tra kh ny bng s dnh bm ca dch qu trn tha.(nu dch qu khng b chy xung th sn phm hnh thnh).

9. Trong ni thanh trng, cc l thy tinh c un si khong 20 pht v khi l vn nng, rt sn phm paste nng n ming l, sau y np.

10. t cc l sn phm vo nc si trong mt thi gian. 11. Sau lm ngui trong 2 gi v bo qun iu kin tt. K thut ch bin puree c chua n gin 1. Lm theo cc bc t 1-5 trong k thut ch bin paste. 2. t ni dch qu ln bp, nh la v c c n 8-24oBx (kim tra: ly mt t sn phm v ln mt t giy, nu sn phm chy xung mt cch t t, th sn phm puree hon thnh) 3. Cho thm 1% mui, khuy u v nhc ni ra khi bp. 4. Lm tng t cc bc t 8-11 trong k thut ch bin paste.


E. QUN L CHT LNG RAU QU THC TI V TRIN VNG M u

Bi ny gm hai phn. Phn 1 bao gm s miu t cc c tnh c bn, phn chung, ca knh phn phi rau qu ti, i tng tc ng n s qun l knh. N cng trnh by cc cng c ch cht trong vic qun l knh phn phi sn phm ti, lin kt ngi nng dn vi th trng to ra s thay i t sn phm y ti sc ht ca th trng. Phn 2 bn v cc nguyn tc v phng php c s dng trong vic qun l knh phn phi sn phm ti. c thc hin bng cch phn tch cc hin tng trong knh t u vo-qu trnh-u ra v cc c tnh cng nh s b tr khc nhau ca ngi sn xut v ngi iu hnh ng gi.

T nhng im lu v cng ngh, qun l knh phn phi cn phi xc nh c tm nhn v mc tiu r rng. iu ny thay i ty theo tng nh qun l c lin quan. Thc hnh qun l s khc nhau tng nc v tng loi sn phm bi v cc ngun lc khc nhau, s u tin pht trin ca t nc, cc yu cu k thut,.v.v. Vic qun l knh phn phi phi quan tm n cc yu t trong v ngoi nc. Cc knh phn phi s c qun l mt cch hiu qu v cnh tranh bi nhng ngi ph hp, ni ph hp v thi gian ph hp. Gii thiu chung

Vic qun l knh i vi thc phm lm tin trin mnh m phn ng vi cc p lc trong v ngoi nc v mi quan h gia cc nh qun l t sn xut n tiu th. Knh phn phi c c trng bi h thng trung gian da trn sc cung v gi bn. S o ngc dn dn ca knh sn phm thc phm trong sut thp k qua trao quyn lc vo tay khch hng. Cng ngh sn xut ti phi i mt mt cch kh khn vi nhng thch thc mi, do vic sn xut manh mn v h thng tiu th khng chuyn nghip. Ngi sn xut phi quan st kch cu thng qua nhng thng tin, s hp tc v m phn gia nhng ngi sn xut tm kim mi lin kt ph hp vi cc on th trng khc nhau to nn v tr tt hn t c mc gi cao hn cho ngi iu hnh sn xut. y l ti liu kim tra cc c tnh ca cng ngh sn xut ti v cc kha cnh k thut c bao gm trong s la chn ca ngi iu hnh knh vi cc vn chung quanh ginh phn thng, tip cn th trng v c mc gi cao. Nhng c th ring ca rau qu

y ni n vai tr ca con ngi trong qu trnh sn xut, phn phi sn phm n th trng. Vic pht trin cc mi quan h cht ch gia cc nh cung cp v ngi tiu th ng mt vai tr rt quan trng trong vic qun l mng li phn phi. Di y l cc c im trong qu trnh phn phi cc sn phm cy trng: 1. T ng rung n th trng, mng li phn phi phn khc c tnh chuyn ha c thc hin bi nhng thnh vin c th. Cc thnh vin khc nhau thuc cc nn x hi, kinh t, vn ha khc nhau. Nhiu ngi coi tnh b mt l cha kha ca s thnh cng. S mu thun v khng tin cy ln nhau gia cc thnh vin l ph bin, trong khi s kt hp gia h li ng vai tr ngha trong mng li phn phi. y l ng lc v l phng kt bt bin trong vic giao ko


gia cc thnh vin trong mng li. S lin kt yu s quyt nh s ln mch ca knh phn phi. 2. Cc hot ng t sn xut n mua bn din ra nh mt b phn kinh t khng theo th tc, khng c s bo v v bo lnh ca php lut. Cc hot ng khng theo th tc ny em li li ch ln hn v hiu qu hn so vi khi b p buc thc hin theo php lut v cc quy nh. V khng theo th tc, nn cc hot ng phi c tnh t duy. Cc thnh vin trong ngnh cng nghip cc sn phm ti khng c khi nim c bn v chi ph li ch hoc khng c k nng qun l. Chnh ph thng bc b hoc chng i cc hot ng khng nghi thc ny. It also dismisses the social rate of return which might be more important than the economic rate of return, particulary for the small-holder participants. 3. Vic sn xut cc sn phm ti c tnh ma v cao, v cn phm vi nh. Chi ph t chc cao. Sn hm ti lun c xem l c khi lng ln, nhng gi tr thp. c im ca cng nghip l tnh mo him cao, s d li nhun thp, gi u vo thp v gi u ra thp, gi phn phi cao, gi qun l kinh doanh cao, chi ph k hoch kinhdoanh v chi ph li ch lun bin i, linh ng, v c th thng lng. C rt t cc du hiu v phm vi kinh t. Rt kh tp hp cc thng tin v ngun cung cp, c hi, gi c, gi tr, Vic cp vn v h tr k thut cho cc sn phm nh l rt kh khn. 4. Sn xut cc sn phm cy trng, trong mt phm vi iu kin nht nh, c tnh c trng cao. Kin thc chuyn mn v sn xut rau qu cho thng mi l yu t ct yu nht cho s thnh cng ca cng nghip. Cc sn phm ti rt d mt gi tr do thi hng, tn thng vt l, tn thng do nhit v m khng ph hp. Mi nguyn nhn ca s tn tht ny u c c im ring, c gii hn, v i hi phi c cch x l sau thu hoch tng ng. Nhng c im c hu ny ca sn phm ti cn c mi thnh vin quan tm trong k hoch qun l v hot ng qun l. 5. Nhn thc ca ngi tiu dng v yu cu cht lng thc phm ang c s thay i. Trong sut nhng nm cui ca thp k 70, gi c l yu t quyt nh chnh. Sau n nhng nm u thp k 80, yu t quyt nh l yu cu v cht lng cm quan (nhn thy c), c bit l ti mi ca sn phm, v n cui thp k 80 l tnh tin dng ca sn phm. T nm 1990 n 2000, ngi ta cnh bo nhiu v d lng thuc bo v thc vt. T nm 2000 n nay, bn cnh d lng ha cht l vn an ton thc phm, bao gm s nhim khun v mt s yu t khc. Vn ny cn tip tc c quan tm hng u, v vic thc hnh v sinh ang c nhn mch gii quyt n. Hin nay vn mi trng v lao ng cng ang c

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