Hun
Cc phng php kim tra nguyn liu trong cng ngh sn xut go
ti: Tm hiu cc phng php kim tra nguyn liu trong cng ngh sn xut
go
B CNG THNGTRNG H CNG NGHIP THC PHM TP.HCMKHOA CNG NGH THC
PHM
Tp. H Ch MinhThng 12/2013GVHD: VNH LONGNHM THC HIN:1. ng Ngc
Hiu20051101722. Nguyn ng Hun20051101963. H Th Lnh20051102324. H Th
Nhung20051103615. ng Th Bch Trm20051105756. Mn : Cng ngh sau thu
hoch
Mc lcLi m u31.Gii thiu chung v tnh hnh sn xut go41.1Tnh hnh la
go th gii v Vit Nam41.1.1La go trong nn kinh t th gii41.1.2 V tr ca
la go trong nn kinh t nc Vit Nam51.2Vai tr ca go62.Cc phng php kim
tra nguyn liu trong qu trnh sn xut go72.1Cu to ca ht la v cc ch tiu
nh hng n cht lng go72.1.1 Cu to ca ht la72.1.2Cc ch tiu nh gi cht
lng go82.2Cch ly mu kim tra nguyn liu102.2.2Mc ch ly mu102.2.3Yu cu
ly mu112.2.4K thut ly mu112.3Phng php kim tra nguyn liu122.3.1Kim
tra loi v ging la122.3.2Phng php xc nh m132.3.3Kim tra ln v ng u ca
ht.172.3.4Kim tra sch, tp cht ca ht222.3.5Kim tra kch thc hnh dng
ca ht242.3.6Kim tra tnh cht cm quan ca ht thc252.3.7Kim tra mc gy
hi ca cn trng bng phng php th kn ca thc252.3.8Kim tra d lng thuc bo
v thc vt trong go bng phng php sc k kh.263.Kt lun v nh hng pht
trin324.Cu hi n tp33Ti liu tham kho36
Li m uVit Nam nm trong kh hu nhit i gi ma thun li, thin nhin u
i, mng li sng ngi dy c, ph sa bi p hng nm nn Vit Nam c nhiu li th
trong sn xut la go, sn lng hng nm ca c nc t 35 37 triu tn thc,
trong ch s dng khong 15 triu tn (tng ng 7 triu tn go) xut khu, cn
li l tiu th trong nc v b sung d tr quc gia. Th mnh v la go c sn xut
2 khu vc ln l ng bng Sng Cu Long v ng bng Sng Hng a Vit Nam tr thnh
nc xut khu go ng hng th 2 trn th gii ch sau Thi Lan. Trong nhng nm
gn y, khi Vit Nam chnh thc gia nhp vo T chc thng mi th gii to iu
kin cho hng nng sn Vit Nam ng vng trn th trng quc t, s mua bn trao
i hp tc kinh doanh ngy cng tng nn yu cu v cht lng cng c ch trng i
hi phi c mt tiu chun nht nh mua bn c thun li hn. Tuy nhin xt v phng
din chung hin nay th cht lng go sn xut ti Vit Nam cng khng ng u,
phn ln cc loi go cht lng cao t tiu chun xut khu th phn ln tp trung
cc Cng ty ln c y trang thit b hin i phc v cho vic ch bin v ngn vn
ln nn thu mua c nguyn liu t cht lng cao. Cn cc doanh nghip nh th
cht lng go cng ch p ng cho th trng ni a. Nguyn nhn phn ln l do cc
doanh nghip nh thiu vn u t vo trang thit b hin i v nguyn liu u vo
cng khng n nh nn cht lng sn phm u ra t cht lng khng cao. c c mt loi
go cht lng th vic s dng cc phng php kim tra trong sut qu trnh bo
qun go l rt quan trng. v hiu r cc phng php kim tra th hm nay nhm
xin c gii thiu r hn v vn ny thng qua ti tm hiu cc phng php kim tra
nguyn liu trong qu trnh sn xut go.
1. Gii thiu chung v tnh hnh sn xut go1.1 Tnh hnh la go th gii v
Vit Nam1.1.1 La go trong nn kinh t th giiTheo pht trin ca sc sn xut
v phn cng lao ng quc t, nhu cu ca con ngi ngy cng phong ph, a dng.
Tuy nhin nhu cu v n v mc vn l nhu cu cn thit hn c, trong nhu cu v n
ung li ng vi tr s mt trong i sng hng ngy. Bi vy, lng thc tr thnh yu
t c ch trng hng u. Thc t trong nhiu thp k qua, th gii lun quan tm,
lo lng n vn lng thc nh mt ti thi s cp bch. Nhiu sch bo, nhiu t chc
v c nhn, nhiu cuc hi tho quc gia v quc t thng xuyn cp n chng trnh
an ninh lng thc quc gia v ton cu. Lng thc lun l mi quan tm ln ca c
loi ngi do nguy c nn i nghim trng ang e da nhiu dn tc. Theo s liu
ca lin hp quc, hin nay trn th gii c khong trn 800 triu ngi nhng nc
ngho, nht l Chu Phi thng xuyn b thiu lng thc trong khong 200 triu l
tr em. Trung bnh hng nm th gii c gn 13 triu tr em di 5 tui b cht do
thiu dinh dng ti thiu v nn i nghim trng. Do Hi ngh dinh dng quc t i
n kt lun rng: Gii quyt kp thi vn lng thc l trung tm ca mi c gng hin
nay pht trin kinh t x hi. Theo thng k nng nghip ca FAO, cc loi cy
lng thc c sn xut v tiu th trn th gii bao gm trc ht 5 loi c th: la
go, la m, ng, la mch v k. Trong la go v la m l 2 loi lng thc c sn
xut v tiu dng nhiu nht. Vi nhu cu trung bnh hin nay trn th gii v la
go, mc tiu th go bnh qun u ngi l 120-130 kg/nm, th sn lng la go hin
nay trn th gii c th duy tr s sng cho khong 3008 triu ngi chim gn
53% dn s th gii. Tuy sn lng la go thp hn la m mt cht, nhng cn c vo
t l h hao trong khu thu hoch, lu thng v ch bin, cn c vo gi tr dinh
dng ca mi loi, ring la go ang nuI sng hn mt na dn s trn th gii. Gn
na dn s cn li c m bo bng la m v cc loi lng thc khc.iu ny ch r v tr
ca la go trong c cu lng thc th gii v trong i sng kinh t quc t.1.1.2
V tr ca la go trong nn kinh t nc Vit NamVit Nam l mt trong nhng nc
c ngh truyn thng trng la nc c xa nht th gii. Nng nghip trng la va m
bo an ninh lng thc quc gia, va l c s kinh t sng cn ca t nc. Dn s nc
ta n nay hn 80 triu ngi, trong dn s nng thn chim gn 80% v lc lng
lao ng trong ngh trng la chim 72% lc lng lao ng c nc. iu cho thy
lnh vc nng nghip trng la thu ht i b phn lc lng lao ng c nc, ng vai
tr rt ln trong nn kinh t quc dn.Bn cnh , u th ln ca ngh trng la cn
th hin r din tch canh tc trong tng din tch t nng nghip cng nh tng
din tch trng cy lng thc. Ngnh trng trt chim 4/5 din tch t canh tc
trong khi la gi v tr c tn, gn 85% din tch lng thc.Nh vy bn cnh s
thu ht v ngun lc con ngi th s thu ht ngun lc t ai cng li khng nh r
v tr ca la go trong nn kinh t quc dn.Xut pht t thc tin , ng v Nh nc
ta lun nhn mnh v tr ca la go Vit Nam: la go ng vai tr quyt nh vn
cung cp lng thc cho c nc v chi phi su sc s pht trin kinh t quc dn.
T , Chnh ph ra cc chnh sch pht trin nng nghip ni chung v la go ni
ring, nh: chnh sch u t vt cht k thut thch ng v thu li, ging la, thm
canh, qung canh la qua tng thi k. La go c a vo 2 trong 3 chng trnh
kinh t ln ca quc gia (nh vn kin i hi ng ton quc thng 12/1986 nu).
Nh , t nm 1989 n nay kim ngch xut khu go khng ngng tng, mang li
ngun thu ngoi t ln gp phn khng nh cho cng cuc i mi v xy dng t nc.
Cng do thc hin thc hin chng trnh lng thc, Vit Nam bin t nc nhp lng
thc hng nm khong 1 triu tn thnh nc xut khu 7- 8 triu tn go hng
nm.
1.2 Vai tr ca go Sn phm chnh ca cy la l go lm lng thc. T go c th
nu cm, ch bin thnh cc loi mn n khc nh bnh a nem, ph, bnh a, bnh
chng, bn, ru. Ngoi ra cn bnh rn, bnh tt, bnh gi v hng chc loi thc
phm khc t go.Gi tr dinh dng ca la go tnh theo % cht kh so vi mt s
cy ly ht khcHm lngLoihtTINHBTPROTEINLI PITXENLULOZATRONC
La62,47,92,29,95,711,9
La m63,816,82,02,01,813,6
Ng69,210,64,32,01,412,5
Cao lng71,712,73,21,51,69,9
K59,011,33,88,93,613,0
Tinh bt:Hm lng tinh bt 62,4%. L ngun ch yu cung cp calo. Gi tr
nhit lng ca la l 3594 ca lo. Tinh bt c cu to bi Amylo se v
amylopectin. Amylose c cu to mch thng v c nhiu go t. Amylopectin c
cu to mch ngang v c nhiu go np.Protin:Cc ging la Vit Nam c hm lng
Protin ch yu trong khong 7- 8%. Cc ging la Np c hm lng prtin cao hn
la t.Lipit:Ch yu lp v go. Nu go xay l 2,02% th go xt ch cn
0,52%Vitamin:Trong la go cn c 1s vi ta min nht l vitamin nhm B nh
B1, B2,B6, , PP... lng vitamin B1 l 0,45 mg/100 ht ( trong phi 47%,
v cm 34,5%, ht go 3,8%).2. Cc phng php kim tra nguyn liu trong qu
trnh sn xut go2.1 Cu to ca ht la v cc ch tiu nh hng n cht lng
go2.1.1 Cu to ca ht laCu to ca ht la gm nhng thnh phn sau: 2.1.1.1
V tru- L lp bao ngoi cng ca ht la. - Gm cc t bo rng c thnh ha g c
thnh phn l cellulose. - Cc t bo v tru c kt vi nhau nh khong v
lignin. - V tru thng c gn ni r, x x v rp. - Mu sc ca v tru kh a
dng: Vng, vng nu, vng rm- dy v tru ty thuc vo ging ht, vo my: Trong
khong 0.12 0.15mm, chim khong 18 19.6% so vi ton ht. 2.1.1.2 V qu v
v ht- V qu: Lin kt khng bn vi v ht.- Thnh phn v qu thng cha
cellulose, pentosan, pectin v khong.- Trong cng mt ht, chiu dy lp t
bo v qu khng ging nhau, gn phi, lp v qu l mng nht. - V qu lin kt
cht ch vi lp aleurone.- So vi v qu th v ht cha t cellulose hn nhng
nhiu protid v glucid hn. 2.1.1.3 Lp aleurone- Bao bc ni nh v phi.-
Chim khong 6 12% khi lng ht.- Trong t bo, lp aleurone c cha nhiu
protid, tinh bt, cellulose, pentosan, cc git lipid v phn ln cc
vitamin v khong ca ht. V th trong qu trnh ch bin ht, khng nn xay xt
qu k gi li cc vitamin v khong cht. Tuy nhin do c nhiu cht dinh dng,
nht l protein nn go cn nhiu lp aleurone kh bo qun, d cn trng v vi
sinh vt pht trin ph hoi. - Do i vi go xut khu hoc cn bo qun lu, ngi
ta phi xt trng, loi b ht lp aleurone, mc d b mt mt s cht dinh dng.
- Khi xay xt ht, lp aleurone b vn ra thnh cm. 2.1.1.4 Ni nh- Ni nh
l phn d tr cht dinh dng ca ht.- Cc t bo ni nh kh ln, thnh mng v c
hnh dng khc nhau. - Thnh phn ha hc ca ni nh: Tinh bt v protid, ngoi
ra cn cha mt lng nh lipid, mui khong, cellulose v mt s sn phm phn
gii ca tinh bt nh dextrin, ng - Lng vitamin v mui khong trong ni nh
khng nhiu, ta c th lm tng hm lng cc cht ny trong ni nh nh qu trnh
gia cng nc nhit.2.1.2 Cc ch tiu nh gi cht lng go2.1.2.1 Loi v gngHt
khc nhau v loi v ging thng c nhiu c tnh vt l v thnh phn ha hc khng
ging nhau. Khi ht gm ht khc nhau v loi v ging s gy kh khn cho vic
khng ch cc ch tiu k thut ca quy trnh cng ngh. Do khi nhp liu vo nh
my bao gi ngi ta cng ring tng loi m bo ng nht v ging ca khi
ht.2.1.2.2 mLa mi thu hoch thng c m cao nn mt s ging la c th ny mm,
men mc v nm d pht trin lm cho la b h hoc km phm cht. Thng thng m ca
thc khi mi thu hoch t 20-27%. la khng b h hng hoc gim phm cht th
trong vng 48 gi sau khi thu hoch, phi lm kh la m ch cn 20%, sau mi
tip tc x l.2.1.2.3 Kch thc, hnh dngHt thc rt di l ht thc c chiu di
ht go lt ln hn 7 mm.Ht thc di l ht thc c chiu di ht go lt t 6 mm n
7 mm.Ht thc ngn l ht thc c chiu di ht go lt nh hn 6 mm.Kch thc ca
ht thc khc nhau s lm cho khi lng ring ca n khc nhau, chnh v vy s lm
cho gi thnh ca chng s b gim. ng thi nu cc ht thc c hnh dang khc
nhau nh c ln cc ht b nt m, xu x th s to iu kin cho vi sinh vt v cc
loi cn trng pht trin v s lm h hng sn phm.2.1.2.4 Tp chtSau khi p,
tut, cn loi b tp cht v c (ct, si, , kim loi...) cng nh cc tp cht hu
c (l ti, l kh, rm r, c khi l phn gia sc...) ln vo khi tut.Ngi ta
chia cc loi tp cht trong khi ht lng thc lm 3 loi: Tp cht rc gm tp
cht khong (, ct, si), tp cht hu c ( rm, mnh, l), ht cy khc, ht c
di.. Tp cht ht gm nhng ht gy, ht cha chn, ht mt v Tp cht st, mnh
kim loi2.1.2.5 v ca htV l phn khng c gi tr dinh dng, do v cng thp
th cht lng ca ht cng cao. v ca ht thay i theo ging, iu kin trng
trtHt la c v 17-24% trung bnh 19%
2.1.2.6 ln v ng u ca cc htHt ln c t l nhn cao hn ht nh cng ca ht
cng thng cao hn. ht ln d lm sch d bc v hn. Khi ch bin th nng sut x
nghip cao, t l thnh phm cao, cht lng tt, thng biu din ln bng trng
lng 1000 ht hoc kch thc ht.Khi ht ng u l gm t nhng ht gn nhau theo
mt kch thc no , khi ht khng ng u s nh hng n t l v cht lng thnh phm
khi ch bin.2.1.2.7 Mc gy h hi ca cn trngTy theo m v mc tp nhim th
mc h hi do cn trng s khc nhau. Nu thc c m thp v cc ht c ng u, khng
c nhiu tp cht th cn trng t lm h hi.2.1.2.8 Cm quanMu sc, hnh dng,
kch thc, mi v, gin cng nh hng rt ln n cht lng ca sn phm.2.2 Cch ly
mu kim tra nguyn liu2.2.2 Mc ch ly muLy mu l khu u tin quan trng
trong thc phm v mu phn nh chnh xc mi c im chat lng v phi c trng cho
thnh phn trung bnh ca l sn phm.Ly mu khng ng phng php, kt qu phn
tch mu th s khng phn nh ng c tnh ca l sn phm, t dn n vic nh gi khng
ng cht lng ca l sn phm .Mc ch ca ly mu:- Kim tra qu trnh sn xut-
Kim tra nghim thu- Xc nh c trng ca l hng- tin hnh cc php th- nh gi
th trng- nh gi cht lng sn phm2.2.3 Yu cu ly mu Mu thc phm phi i din
cho c l hng ng nht. Mu hng ly a i kim tra phi l mu trung bnh, ngha
l sau khi chia thnh l hng ng nht, mu s ly u cc gc, pha trn, pha di,
gia l hng v trn ng u. Thc c ly trn, di,gia cc bao hoc cc ng i vi l
hng ng nht T l ly mu t 0,5 n 1% ty theo s lng nhng mi ln ly khng t
hn lng cn thit gi mu v kim tra. Nhng khng c t hn lng mu ti thiu.
Lng mu ti thiu l lng mu kim tra. Trong trng hp khng lu mu, mi thay
i cn ghi r trong bin bn ly mu v bin bn bn giao mu. Qu trnh ly mu
phi c gi st v ghi chp y . Sau khi ly mu chia thnh mu th trung bnh
gi i kim gi i kim tra.2.2.4 K thut ly mu2.2.4.2 Ly mu nhin n
ginThng p dng khi ly mu trong kho, trong mt lng tp hp ta ly mu bt
k. a im bt k thng c da vo bn ngu nhin.Theo cch ly mu ngu nhin n gin
ny, mu s i din kh cht cho l hng nn ta c chnh xc cao nhng th t ly
khng theo mt th t no nn ly mu kh vt v, i khi khng thc hin c.2.2.4.3
Ly mu ngu nhin h thngThng p dng cho cc dy chuyn sn xut lin tc hoc
trong thi gian chuyn hng vo kho cha. K thut nu ln cch ly mu sn phm
theo chu k thi gian sn xut hoc th t sn phm c sn xut ra trn dy chuyn
.
2.3 Phng php kim tra nguyn liu2.3.1 Kim tra loi v ging la Loi v
ging la c nh sn xut v cung cp la cung cp thng tin cho ngi mua, cng
ty t hng.Cc ging la thng thng c phn loi theo cu trc v hnh dng ht go
ca chng. Da vo ngi ta c th phn bit c ging la. V d, mt ging la thm
ca Thi Lan cho loi go ht di v tng i t dnh, do go ht di cha
tamylopectinhn so vi cc ging ht ngn. Cc nh hng Trung Hoa thng thng
a ra mn cm nu t go ht di. Cc loigo npl go ht ngn.Go Nht Bnl loi go
ht ngn v dnh. Go dng nu rusakl mt loi go khc.Cc ging go thm c hng v
thm c bit; cc ging ng ch nht bao gm cc loi Basmati, go Patna k trn
cng nh cc ging lai t M c bn di tn gi thng phmTexmati. N l ging lai
gia Basmati v ging go ht di M gy ra nhiu tranh lun. C Basmati v
Texmati c hng v tng t nh bng ng. Cc ht ging la c phn cp nh sau: Ht
ging tc gi (TG) l ht ging thun do tc gi chn, to ra. Ht ging la siu
nguyn chng (SNC) l ht ging la c nhn ra t ht ging tc gi hoc phc trng
t ht ging sn xut theo quy trnh phc trng ht ging siu nguyn chng v t
tiu chun cht lng theo quy nh. Ht ging la nguyn chng (NC) l ht ging
la c nhn ra t ht ging siu nguyn chng v t tiu chun cht lng theo quy
nh. Ht ging la xc nhn (XN) l ht ging c nhn ra t ht ging nguyn chng
v t tiu chun cht lng theo quy nh Phng php kim tra ti Nguyn tcTrong
qu trnh bo qun, cht bo c trong thnh phn go b oxi ha chuyn thnh axit
bo lm cho tnh axit tng ln. Bng cch kim tra pH, ta c th kim tra c
ti.Bng cm quan thng thng, b phn kim tra nh my kh c th bit c chnh xc
go c hay go mi. V l thuyt go c th tm tr 2-3 thng, nhng ngng bo qun
thi gian ti u go gi ti th kh c th xc nh c. Phng php o tiS dng cht
ch th mu. Bng phn ng ha hc, cn c mu hin th cho ta bit mu c tnh axit
hay khng.
Dung dch th : Pha ch dung dch A : Ha tan 0,1 methyl red v 0,3g
Bromotymol blue trong 150ml cn tinh khit v pha long n th tch 200ml
Pha ch dung dch B: Pha long 1ml dung dch A vi 50ml nc ct.Cch th: 5g
go vo trong 10ml dung dch B Lc mt lc v quan st s i mu ca dung dch
sau 10 pht. i chiu vi mu mu sau: Mu xanh : Go la mi Mu xanh vng: Go
la cn mi Mu vng: Go la c. Mu cam: Go la qu c2.3.2 Phng php xc nh m
m l ch tiu quan trng trong xay xt ch bin, nh hng trc tip n t l thu
hi, nng sut hay v gi ca thnh phm.Ngoi ra, m cng l mt ch tiu quan
trng v cht lng ht cng nh cht lng sn phm, v khng nhng n c th th hin
sn phm tt hay xu m cn nh hng rt ln n cc qu trnh.Vic xc nh m chnh l
xc nh lng nc t do trong ht. Trong qu trnh ly mu v chun b mu kim
nghim khng c lm thay i m ca sn phm. Ngi ta thng xc nh m vo nhng thi
k sau:+ Trc lc nhp kho quy nh phng php v thi gian bo qun.+ Trc khi
iu vn xc nh kt qu bo qun, phng tin vn chuyn.+ Trong qu trnh bo qun
xc nh s din bin ca ht.+ Trc v sau khi x l kho bng thuc ha hc c th
quy nh liu lng thuc, phng php x l, phng php bo qun.La sau thu hoch
thng c cc h nng dn h m ch yu bng phng php lm kh t nhin bng nng lng
mt tri (phi nhanh) . Vic xc nh m t yu cu hay cha ch yu bng kinh
nghim (cn th) nn khng chnh xc. V vy cn phi c mt phng php ti u
hn.2.3.2.1 My o m nng sn, ng cc TK-100GMy o ng cc TK-100G l mt cng
c mnh m v linh hot vi u d rng ph hp vi nhiu loi nguyn vt liu cn o
m: nh cc loi ht (la, thc, go), ng, c kh, u nnh, la m, ha cht nguyn
liu, ht nha, x phng, bt, t v nguyn liu si khc... ngoi ra my cng c
dng o m t trong bng. Thng qua kim tra dn in t t cc chn ca my, m ca
cc loi ng cc c th thu c nhanh v chnh xc.n s hin th chnh xc iu kin m
ca nguyn vt liu cn o qua gip ngi s dng lp biu m v theo di nhng thay
i trong iu kin chnh xc v ng tin cy (tiu chun o lng Chu u - CE).My
cn c s dng kim tra m bng trong qu trnh chuyn giao, mua bn, lu tr v
gia cng.My hot ng da trn phng php khng in, t ng thay i theo nhit mi
trng.
My o mThng s k thutMn hnh: mn hnh LCD k thut s (4 s)Phm vi o: 6
- 30%Nhit o: 0 600C m: 5% - 90% phn gii: 0.1 chnh xc: 0,5%Ngun: 4
pin 1,5V AAAChng nhn: tiu chun Chu u (CE)u im : ng kim tra m ca
nguyn liu vi s lng nhiu trong quy m cng nghip. Nhng c nhc im l chnh
xc khng cao.2.3.2.2 Phng php xc nh m bng cch sy kh.Phng php xc nh m
ca ht bng cch sy kh c coi l chnh xc v thng dng m ta gi l phng php
trng ti. Phng php xc nh m bng cch sy kh c tin hnh nh sau: Mu trung
bnh c trong phng t nht 1 gi, sau ly ra nghin nh. Lng mu ly khong 50
g (i vi ht to) v 20 g (i vi ht nh). Ht c nghin nh v ry qua sng c ng
knh = 0,5 mm, lng mu lt qua khng di 5% v cn li cho ln sng 1 mm m
khng di 10% (ch trong qu trnh nghin mu khng nn cho mu nng ln). Sau
khi nghin ht thnh bt mn, phn thnh lng mu, mi mu 5 gr. Ly hp nhm, xc
nh trng lng tng hp (k c np) l G0. Cho 2 mu vo hai hp nhm y np li v
cn c trng lng l G1. Cho t sy nng ln 140 1450C ri nhanh chng a hp (
m np v lng vo y) vo t sy. iu chnh nhit 1300C sy trong 40 pht (k t
lc sy 1300C). Ht thi gian sy ly hp nhm y np li v em vo bnh ht m 20
pht ri cn ring tng hp nhm c mu sau khi sy ta c trng lng l G2. C th
sy nhit 1050C cho n khi trng lng khng i. Kt qu c xc nh theo cng thc
sau:W = G0: Trng lng ca hp nhm c np khi cha c mu (g)G1: Trng lng ca
hp nhm c np khi c mu cha sy (g)G2: Trng lng ca hp nhm c np khi mu
sy (g)Kt qu ca trng lng mu c cn song song, nu sai lch khng qu 0,5%
c coi l t yu cu. m ca ht s l trung bnh cng ca hai mu trn.Phng php
xc nh m bng cch sy kh c chnh xc cao thng dng xc nh m trong quy m
nh, kim nghim trong phng th nghim.2.3.2.3 Kim tra m nh cm quanNgoi
hai phng php kim tra m bng phng php o bng my v sy kh th cn phng php
cm quan kim tra m. Ngi kim tra c th dng tay ca mnh trc tip kim tra.
Phng php ny kim tra m nhanh nhng khng c chnh xc, cn mang tnh ch
quan ca ngi kim tra.2.3.3 Kim tra ln v ng u ca ht.2.3.3.1 Sng phn
loi kiu zig- zag (sng Pakis)y l loi sng cng dng c bit dng cho phn
loi hn hp thc go sau khi xay. Thc sau khi xay gm c go lc ( tch v
tru), v tru v thc cha c xay. V tru c ly ra nh mt h thng qut ht hoc
thi. Go lc v thc c a sang sng phn loi phn ring. Phn go lc tch ra c
chuyn sang cng on xt tch v la, phn thc cha tch v s c hi li cng on
xay. Nh vo ta c th kim tra c cht lng ca sn phm go.
Nguyn l hot ngNguyn tc phn loi ca sng zig- zag da theo khi lng
ring v nhm b mt. Mt sng l mt tm kim loi phng v nhn bng, c t hi
nghing, gc nghing c th iu chnh c. Trn mt sng c cc g hnh zig- zag lp
song song nhau to thnh mt khe cng c dng zig-zag. Sng c truyn chuyn
ng theo phng vung gc vi cc g vi tn s trong khong 90-120 ln/pht.Hn
hp thc go c vo gia sng. Khi sng chuyn ng, hn hp thc go do lc qun
tnh b va p mnh ln cc g. Do s khc bit v khi lng ring v nhm, dn n hin
tng phn lp, go c khuynh hng di chuyn xung pha di thp, cn thc c a ln
pha u cao.
Sng zig zagMt tng sng c nhiu khe, thng thng t 5 n 20 khe v mi mt
my sng c th c ti 5 tng sng song song nhau. S khe v tng sng cng
nhiu, nng sut sng cng ln. iu chnh phn loi bng cch iu chnh gc nghing
ca sng. Gc nghing cng ln, thc cng c khuynh hng di chuyn xung di v
ngc li gc nghing nh s lm go i ln pha trn cao cng vi thc. Qu trnh iu
chnh ny cn tin hnh thng xuyn, thng thng i hi ngi iu chnh c kinh
nghim.u im ca sng zig- zag l tit kim c s ln sng. Thc v go lc c kch
thc gn nhau, nu s dng sng phn loi bnh thng rt kh, phi qua hn 10 ln
sng. Nhc im l khng phn ring c hn hp c kch thc ht gn nh nhau.Trong
thc t, sng Pakis thng c iu chnh sao cho hon ton khng cn thc theo
go, do s c mt s lng kh ln go theo thc ln pha trn sng quay li. V vy,
mt my xay khc c b tr xay ring cho lng thc-go hi lu. Sau khi xay lng
hi lu cng c a qua cng sng Pakis, nh vy nng sut ca sng theo qui trnh
ny phi ln hn, tuy vy y l qui trnh c hiu qu xay t cao nht.2.3.3.2
Sng khay (sng git)Sng khay cng l sng dng phn ring hn hp thc go sau
khi xay. Nguyn l lm vic ca n da ln s khc bit khi lng ring v hin tng
phn lp khi chuyn ng gia thc v go.Sng git c cu to gm tm kim loi nhn
lng c dp cc hc lm xen k. Kch thc v hnh dng ca cc hc c thit k sao
cho khi sng chuyn ng, hc s tc dng lc ln khi ht trn mt sng. Sng c t
nghing theo hai chiu sao cho c mt gc cao nht v mt gc thp nht.Hn hp
thc go c a vo gc cao nht. Nh vo chuyn ng ca sng, thc b phn lp v ni
ln trn b mt lp ht. Do c cc hc nn khi sng chuyn ng lp go s c a ln
pha cao ca sng v ly ra mt gc sng. Lp thc nm trn b mt lp go s trt
xung di (trt trn b mt lp go), v s di chuyn xung gc thp nht. Gia gc
ly thc v go l vng hn hp, trong go cn ln thc v s c a tr li pha trc
sng. Tn s chuyn ng ca sng thng l 300 ln/pht. Nng sut ca mt tng sng
c th ti 1-1,5 tn/h
ng di chuyn ca thc, go trn mt sng
Sng khay vi 3 ca ly go, hn hp v thcNguyn l hot ng ca sng khay v
ng i ca thc, go trn mt sng: B mt sng cn phi tht phng bo m qu trnh
phn loi xy ra chnh xc. Trng hp b mt sng b g, lp go mng i, khi sng
git c thc cng chy ln theo go v ngc li mt phn go b trt xung. ch lm,
lp go ln dy hn nn mt phn go khng c y ln v s trt xung theo thc.* u
im ca sng git: Do nng sut mt lp sng nh nn nng sut chung ca c my sng
c th phn loi t rt nh n ln. Cu to nh, gn, d lp t, iu chnh.* Nhc im
ca sng git: Do c nhiu lp sng c b tr chng ln nhau nn kh t ng nht cho
tt c cc lp.
2.3.4 Kim tra sch, tp cht ca ht2.3.4.1 Kim tra sch ca ht sch ca
ht l t l khi lng tnh bng % ca mi ht thuc mt loi cy trng chnh cha
trong mu c bn so vi khi lng ca mu . Song song vi vic xc nh sch phi
xc nh t l ht khng hon thin, t l tp cht v ht c, ht cy trng khc.Phng
php tin hnh:Mu trung bnh c vo sng v sng trong 5 pht vi tc 180
vng/pht. Sau nht ring cc loi ht c tnh l sch, cc ht gy, ht trc v,
nht ring cc loi ht c di v m ng thi ghi tn loi c no chim nhiu nht.Ht
c tri trn tm knh v xc nh cc ch tiu cm quan (mu sc, mi v) cn ch mt
iu l trong qu trnh kim nghim mu trung bnh nu thy mt ht c hoc ht c
ngun gc su bnh thuc i tng kim dch ca nc ta hoc i tng kim dch i ngoi
th mi vic kim nghim s dng li. C quan kim nghim s nim phong mu trung
bnh 1 v ra lnh cm dng l nng sn y hoc l thc ging y gieo trng hoc xut
khu.Ton b tp cht, ht v ch c vo a petri v xc nh ton b khi lng ca tp
cht c tch ra bng sng.Mu kim nghim sch c tri trn tm knh, phn thnh
nhng phn lng sau:+ Phn lng ht tnh vo sch, trong c phn bit vi hatj
khng hon thin.+ Phn lng tp cht (bao gm c ht v ch v tp cht).T l sch
c xc nh theo cng thc sau y: sch s = Cng thc tnh t l ht khng hon
thin:Hkht = T l tp cht: t = 100 sS lng ht c trong 1 kg ht: Hc = K
hiu:S: l khi lng phn lng ht c tnh vo sch.t: Phn lng tp cht trong mu
phn tch (g)T: Tp cht tch ra t mu trung bnh 1 (bao gm ht c, ht v ch,
tp cht) tnh bng (g)K: Cu phn ht khng hon thin (g)s: schc: Lng ht c
trong mu trung bnh.M: Khi lng mu xc nh ht c.2.3.4.2 Kim tra tp cht
ca ht Dng c- Cc thu tinh, chi qut phi kh, sch.- Sng c kch thc l sng
1,60 mm x 20,00 mm c y thu nhn v np y. Cch tin hnhT phn mu th 1, cn
500 g mu vi chnh xc n 0,01 g v ln sng th c lp y sng v y np. Sng bng
tay trong 2 min. ton b phn cn li trn sng vo khay men trng. Nht cc
tp cht v c v hu c trn sng gp vi phn tp cht nh cn li di y sng cho vo
cc thy tinh kh sch, bit khi lng. Cn ton b khi lng tp cht chnh xc n
0,01 g. Tnh ton v biu th kt qu Tp cht ca thc (Xtc), tnh bng phn trm
khi lng, xc nh theo cng thc :
Trong :mtc l khi lng tp cht, tnh bng gam;m l khi lng mu phn tch,
tnh bng gam. Kt qu php th l tr s trung bnh cng ca hai ln xc nh song
song trn cng mt mu th khi s sai khc ca chng khng vt qu 1 % gi tr
trung bnh. Bo co kt qu chnh xc n mt ch s thp phn.2.3.5 Kim tra kch
thc hnh dng ca ht Chun b thit b o kch thc ca ht chnh xc n 0,01 mm
Sau khi kim tra ng u, kim tra tp cht ta t ngu nhin 100 ht thc lt
nguyn vn ln bn o. Dng dng c o kch thc ht tin hnh o chiu di ca tng
ht, tnh bng milimet. Tnh gi tr trung bnh ca chiu di mt ht thc ri
phn loi kch thc ca ht thc theo quy nh.2.3.6 Kim tra tnh cht cm quan
ca ht thc2.3.6.1 Phng php truyn thng.Da vo cm nhn ca cc gic quan ca
con ngi nh gi cht lng go: - Mu sc: Ht thc c mu sc c trng ca ging,
loi. - Mi: C mi t nhin ca thc, khng c mi l.- Trng thi: Ht my, v tru
khng b nt, h.2.3.6.2 My tch ht muHt ng cc c mu khc khng c trng thng
l cc ht khng tt hoc h hng. V vy da vo phng php ny c th kim tra cht
lng cng nhng tnh cht cm quan ca go. tch cc ht c mu khc thng ra khi
khi ht, c th dng my tch ht mu. My tch ht mu lm vic da theo nguyn tc
phn bit ht mu bng cm bin mu ca dng ht ang trt trn rnh. Nu pht hin
ht c mu khc l, mt ng thi kh s thi ht mu ra khi rnh v ri xung mng
hng bn di. My c th tch hu ht cc ht c mu sm ra khi khi ht c mu sng.i
vi go, nng sut my c th t ti 200 kg/h/rnh. Thng thng mi my c th c t
60-80 rnh lm vic ng thi.2.3.7 Kim tra mc gy hi ca cn trng bng phng
php th kn ca thcPhng php kim tra kn ca go l phng php kim tra cht
lng go da vo rng, kn, ht go c b con g n bn trong hay khng, t a ra
bin php x l cho ph hp.- Gn p k kn kht vo vi dn kh v tin hnh ht kh.
- Khi chnh lch mc nc trn p k t 100 mm (tng ng vi p sut m 1000 Pa)
kho van ca ht kh ng thi tt my. Ch p k n nh trong 5 pht, theo di
khong thi gian ct nc gim xung cn 1/2. Nu t mc t 40 pht tr ln th l
go c coi l m bo kn, di mc 40 pht th cn tin hnh cc bin php kim tra x
l. Vic th kn cn lp li 3 ln.- Kim tra, x l mng b thng, h: d tm cc im
thng, h gy lt kh cn chn thi im yn tnh, ht kh ti mc 1000 Pa, tp
trung lng nghe hoc c th dng cc thit b khuych i m thanh thng thng
kim tra pht hin, x l. Trong trng hp thi tit kh hanh, m tng i nh hn
65 % c th dng my ht kh bm khng kh bn ngoi vo l go cho ti khi tm ph
cng phng kim tra pht hin cc im thng, h gy lt kh. 2.3.8 Kim tra d
lng thuc bo v thc vt trong go bng phng php sc k kh.2.3.8.1 Phm vi p
dngTiu chun ny quy nh phng php th ng thi d lng cc hot cht thuc bo v
thc vt (BVTV) trong go, bao gm buprofezin, chlorothalonil,
cypermethrin, difenoconazole, endosulfan, fenpropathrin, fipronil,
hexaconazole v lindan bng sc k kh.2.3.8.2 Nguyn tcD lng cc hot cht
BVTV trong mu th c chit bng hn hp dung mi ete du ha - diclometan v
c xc nh bng thit b sc k kh vi detector cng kt in t (ECD).
S n gin ca phng php sc k kh
2.3.8.3 Thuc thCh s dng cc thuc th tinh khit phn tch, nc t nht t
tiu chun loi 3 ca TCVN 4851 (ISO 3696), tr khi c qui nh khc. Hn hp
dung mi 1, cha te du ha v diclometan vi t l th tch te du ha :
diclometan bng 1 : 1. Hn hp dung mi 2, cha n-hexan v toluen vi t l
th tch n-hexan : toluen bng 9 : 1. Cht chun (buprofezin,
chlorothalonil, cypermethrin, difenoconazole, -endosulfan,
-endosulfan, fenpropathrin, fipronil, hexaconazole v lindan), bit
tinh khit. Dung mi chun gc, nng 1 000 g/ml.Dng cn phn tch cn 0,01 g
tng cht thuc BVTV, chnh xc n 0,01 mg, cho vo cc bnh nh mc dung tch
10 ml , thm toluen n vch v trn Dung dch chun trung gianDng pipet ly
i vi cc dung dch chun gc buprofezin, cypermethrin, difenoconazole
0,4 ml v cc dung dch chun gc cholorothalonil, -endosulfan,
-endosulfan, fenpropathrin, fipronil, hexaconazole v lindan th ly
0,2 ml cho vo bnh nh mc dung tch 50 ml, thm toluen n vch v trn.Nh
vy, trong dung dch chun trung gian, cc hot cht buprofezin,
cypermethrin v difenoconazole c nng 8 g/ml, cc hot cht
chlorothalonil, -endosulfan, -endosulfan, fenpropathrin, fipronil,
hexaconazole v lindan c nng 4 g/ml. Dung dch chun lm vic Dung dch
chun lm vic 1Dng micropipet ly 125 l dung dch chun trung gian cho
vo bnh nh mc dung tch 50 ml, thm hn hp dung mi 2 n vch v trn.Nh vy,
trong dung dch chun lm vic 1, cc hot cht buprofezin, cypermethrin v
difenoconazole c nng 0,02 g/ml, cc hot cht chlorothalonil,
-endosulfan, -endosulfan, fenpropathrin, fipronil, hexaconazole v
lindan c nng 0,01 g/ml. Dung dch chun lm vic 2Dng pipet ly 2 ml
dung dch chun trung gian cho vo bnh nh mc dung tch 50 ml thm hn hp
dung mi 2 n vch v trn.Nh vy, trong dung dch chun lm vic 2, cc hot
cht buprofezin, cypermethrin v difenoconazole c nng 0,32 g/ml, cc
hot cht chlorothalonil, -endosulfan, -endosulfan, fenpropathrin,
fipronil, hexaconazole v lindan c nng 0,16 g/ml. Dung dch chun lm
vic 3Dng pipet ly 10 ml dung dch chn trung gian cho vo bnh nh mc
dung tch 50 ml, thm hn hp dung mi 2 n vch v trn.Nh vy, trong dung
dch chun lm vic 3, cc hot cht buprofezin, cypermethrin v
difenoconazole c nng 1,6 g/ml, cc hot cht chlorothalonil,
-endosulfan, -endosulfan, fenpropathrin, fipronil, hexaconazole v
lindan c nng 0,8 g/ml. Kh nit, c tinh khit khng nh hn 99,999
%.2.3.8.4 Thit b, dng cS dng cc thit b, dng c ca phng th nghim thng
thng v c th nh sau: Bnh nh mc, dung tch 10 v 50 ml. Pipet, dung tch
0,5; 2 v 20 ml. Micropipet, c th o t 50 l n 200 l Cc li tm, dung
tch 250 ml. Bnh nn, dung tch 50 ml. Xyranh, dung tch 10 l, chia vch
n 1 l. ng ong, dung tch 50 ml. Cn phn tch, c th cn chnh xc n 0,01
mg. Cn, c th cn chnh xc n 0,1 g. Thit b ng nht Ultra-Turrax, tc
khng nh hn 18 000 r/min. Thit b chng ct quay chn khng. My nghin mu
kh. My li tm, tc khng nh hn 3 000 r/min, c ng li tm dung tch 250
ml. Thit b sc k kh, c trang b nh sau:- injector chia dng v injector
khng chia dng;- detector cng kt in t (ECD);- ct mao qun DB-5, c
chiu di 30 m, ng knh 0,32 mm, chiu dy pha tnh 0,25 m, hoc loi tng
ng;- b bm mu t ng;- my vi tnh hoc my tch phn k.2.3.8.5 Ly muVic ly
mu khng c quy nh trong tiu chun ny. Nn ly mu theo TCVN 5139:2008
(CAC/GL 33-1999).2.3.8.6 Cch tin hnh Yu cu chungTon b qui trnh phn
tch cn c thc hin trong ngy. Nu cng mt lc chun b nhiu mu th tt c cc
mu cn c phn tch trong ngy, s dng b bm mu t ng.
Chun b muMu th c nghin trong my nghin mu kh n khi ng nht. Chun b
phn mu thDng cn cn khong 10 g mu th c ng nht, chnh xc ti 0,1 g, vo
cc li tm dung tch 250 ml. Thm vo cc 15 ml nc, yn nhit phng t nht 1
h. Tip tc cho vo cc 50 ml hn hp dung mi 1, ng ha trong 30 s bng
thit b Ultra-Turrax vi tc 22 000 r/min, sau li tm bng thit b li tm
vi tc 3 000 r/min trong 10 min. Dng pipet ly 20 ml dch lng thu c
cho vo bnh nn dung tch 50 ml v c cn (lm bay hi) bng thit b chng ct
quay chn khng 40 oC, thm 2 ml hn hp dung mi 2 vo thu c phn mu th.
iu kin phn tchNhit bung bm mu: 240 oC
Nhit ct tch:nhit ban u 80 oC gi trong 1 min, tng 40 oC/min n
nhit 160 oC, tng 3 oC/min n 250 oC, tng 10 oC/min n nhit cui 280 oC
v gi trong 10 min.
Nhit detector:300 oC
Tc kh mang (N2):2 ml/min
Tc nit b tr:60 ml/min
Th tch bm mu1 l, khng chia dng
Dng ng chunDng ng chun (tng quan gia din tch pick v nng cht
chun) ca cc hot cht thuc BVTV ti 3 im c nng tng ng trong dung dch
chun lm vic 1, dung dch chun lm vic 2 v dung dch chun lm vic 3. Xc
nhDng xyranh bm dung dch phn mu th vo thit b sc k kh, lp li 2 ln.
Dng ng chun xc nh nng ca phn mu th khi bm vo my. Nu nng ca mu th nm
ngoi ng chun th iu chnh bng cch pha long dung dch phn mu th (khng
phi pha long lng mu bm).2.3.8.7 Tnh kt quD lng tng hot cht thuc
BVTV, X, biu th bng miligam trn kilogam (mg/kg), c tnh theo cng
thc:
l nng ca phn mu th khi bm vo my, tnh bng microgam trn mililit
(g/ml);
l th tch phn mu th, tnh bng mililit (ml);
l th tch dung mi dng chit, tnh bng mililit (ml);
l th tch dch chit c ly ra lm bay hi, tnh bng mililit (ml);m l
khi lng mu th, tnh bng gam (g);P l tinh khit ca cht chun, tnh bng
phn trm (%).
3. Kt lun v nh hng pht trin Go c vai tr quan trng i sng con ngi,
v vy cn c cc bin php bo qun la go cho hp l m bo lng thc cung cp ngi
dn Vit Nam v trn th gii. Trong qu trnh sn xut go, phi kim tra nguyn
liu go trc khi sn xut cng nh trc khi a ra th trng, nhm m bo cht lng
v an ton v sinh thc phm cho ngi dn. Thnh lp nhiu i kim tra cht lng
go thng xuyn cc c s nhm pht hin go km cht lng.
4. Cu hi n tp
Cu 1: Trong tiu chun nh gi cht lng go, v loi v ging ngi ta da vo
tnh cht g nh gi cht lng go?A.. Tnh cht vt l, sinh hcB.. Tnh cht
sinh hc v ha hcC.. Tnh cht ha hc v vt l.D. Tnh cht vt l, sinh hc v
ha hc. [
]Cu 2: Trong phng php o ti vi ch th methyl red, kt qu kim tra cho
dung dch mu vng th kt lun?A.. Go qu mi.B.. Go cn mi.C.. Go c.D.. Go
qu c.[
].Cu 3: Th no gi l go nguyn?A.. L go sau khi xay xt c chiu di ln hn
75% chiu di chun.B.. L go sau khi xay xt c chiu di ln hn 85% chiu
di chun.C.. L go sau khi xay xt c chiu di ln hn 95% chiu di
chun.D.. L go sau khi xay xt c chiu di ln hn 65% chiu di
chun.[
]Cu 4: My tch ht mu lm vic da trn nguyn l no?A.. My tch ht mu lm
vic da theo nguyn tc phn bit ht mu ca dng ht ang trt di rnh.B.. My
tch ht mu lm vic da theo nguyn tc phn bit ht mu ca dng ht ang trt
trn rnh.C.. My tch ht mu lm vic da theo nguyn tc phn bit ht mu bng
cm bin mu ca dng ht ang trt di rnh.D.. My tch ht mu lm vic da theo
nguyn tc phn bit ht mu bng cm bin mu ca dng ht ang trt trn rnh.
[
]Cu 5: Trong phng php kim tra sch ca go mu trung bnh c vo sng v sng
trong bao lu vi tc bao nhiu?A.. Mu trung bnh c vo sng v sng trong 5
pht vi tc 180 vng/pht.B.. Mu trung bnh c vo sng v sng trong 6 pht
vi tc 180 vng/pht.C.. Mu trung bnh c vo sng v sng trong 5 pht vi tc
200 vng/pht.D.. Mu trung bnh c vo sng v sng trong 6 pht vi tc 200
vng/pht.[
]Cu 6 : Trong phng php th kn ca l gao, khi kim tra x l mng b thng
ta c th ht kh ti mc no?A.. 100 Pa.B.. 200 Pa.C.. 1000 Pa.D.. 2000
Pa.[
]Cu 7: Kim tra d lng thuc bo v thc vt trong go bng phng php sc k
kh, c my dung dch chun lm vic ?A.. 2B.. 3C.. 4D.. 5[
]Cu 8: Kim tra d lng thuc bo v thc vt trong go bng phng php sc k
kh, iu kin phn tch nhit bung bm mu l bao nhiu?A.. 2100CB.. 2200CC..
2300CD.. 2400C[
]Cu 9: m ca thc khi mi thu hoch khong bao nhiu % ?A. 15%- 22 %B.
20% - 27%C. 22% - 35%D. 35% - 40%[
]Cu 10: My o m nng sn, ng cc hot ng da vo nguyn tc no.A. My hot ng
da trn phng php khng nhit, t ng thay i theo m mi trng . B. My hot
ng da trn phng php khng in, t ng thay i theo nhit mi trngC. My hot
ng da trn phng php hp th nhit , t ng thay i theo nhit mi trngD. Tt
c u sai[
].Cu 11: Thnh phn bao bc ni nh v phi chim khong 6 12% khi lng ht l
?A. V htB. V quC. Lp aleuroneD. V tru[
].
Ti liu tham kho1.
http://luanvan.net.vn/luan-van/de-tai-phuong-phap-sac-ky-45604/2.
http://www.ued.edu.vn/khoahoa/file.php/1/_themem/Phan_tich_sac_ki_khi_Th_Vung_.pdf3.
http://doc.edu.vn/tai-lieu/khoa-luan-mot-so-giai-phap-nham-nang-cao-chat-luong-gao-tai-tong-cong-ty-luong-thuc-mien-nam-32256/4.
http://luanvan.net.vn/luan-van/nghien-cuu-sang-phan-loai-hat-nong-san-22684/
BNG PHN CNG CNG VICSTTH TN SINH VINNI DUNG CNG VICMC THC HINCH
K
1NG NGC HIUGii thiu chung v tnh hnh sn xut go, cu hi n tp, lm
wordTch cc
2NGUYN NG HUNPhng php o ti, phng php xc nh m, phng php sng lc,
lm word.Tch cc
3H TH LNHPhng php th kn ca thc (go), phng php xc nh d lng thuc
bo v thc vt trong go bng phng php sc k kh, lm word.Tch cc
4H TH NHUNGPhng php nh gi cm quan, phng php kim tra sch ca ht,
lm powerpoint.Tch cc
5NG TH BCH TRMCu to ca ht la v cc ch tiu nh hng n cht lng go, lm
powerpointTch cc
Cng ngh sau thu hochPage 2GVHD: Vnh Long
