^^^4/ KHOA HOC - CONG NGHE NGHlfiN ClTU QUA TRINH SXY TOI DANG T H A I LAT BANG CONG NGH£ SAY BOM NHIET KIEU DONG DiJkT VAN B E Sdy bom nhiet la mdt cdng nghe sdy, co thd tao dugc trang thai tdc nhan say cd dm thap d nhi?t thap Nguyen ly chung cua qua trinh sdy bom nhiet, ddng thdi su dung chidu Ignh va nong cua he thdng mdy Ignh Qua trinh lam Ignh khdng xudng dudi trang thdi diem suong nham muc dich tdch dm (tgi thidt bi bay hoi) va tiep tuc dugc gia nhiet de tgo nen trang thai khdng khd d nhiet dp nhdt dinh theo yeu cau cdng nghe say (tai thi§t bi ngung tu) Phgm vi hoat dong hieu qud cua say bam nhi?t d ddi nhi^t dp dudi dO^'Cvdi dm tuong ddi khdng cd thd dat dugc - 25% Nhidu kdt qud nghien cuu cho thay tinh phii hgp ciia cdng nghe say bom nhift vdi cdc ddi tugng vat lieu de bi bien ddi chat lugng tdc ddng d nhiet cao nhu rau qud, gia vi, keo [2] [4], [5], [6], [8], [13], [14] Ddc biet cdc sdn pham rau qua giau hdm lugng chat thom de bay hoi, qua trinh say dugc kiem soat budng kin, co the giii Igi vd tri d mdt ndng dp nhat dinh lam chdm qud trinh bay hoi Mdt khdc nhidt dd sdy thdp han chd dugc khd nang bien tinh vd gidm tdc ctia cdc phan ung hod hoc xdy qua trinh say gay mat mau, vi va cac phdn dinh dudng [15], [16] Ngoai say bom nhiet cd tac nhdn say tudn hodn kin la mdt giai phdp tiet kiem nang lugng vd cd the hoat dpng dpc ldp khdng bi phu thudc vao thdi tiet mdi trudng [4], [II], [12], [15] , , Tuy vay, ddng luc cua ca che say bom nhiet d nhi?t dp cdng thdp thi cd xu hudng gidm mgnh so vdi ca che say bdng gia nhiet thdng thudng De nang cao hieu suat cua qua trmh say bom nhidt d ddi nhiet dp thdp la rapt vdn de dang dugc nhieu nha nghien cuu quan tam Sau ddy Id tdm tdt kdt qud budc ddu cua qua trinh tdi uu hoa che dp cdng nghe sdy tdi bang bam nhiet kieu dpng (dgng thung quay) vdi cac yeu td dnh 'TS Vipi CO dien NNva CNSTH ' T S PhoVi?ntruongVi§nCOd[?nNNvaCNSTH Pham Anh Tuan', Chu Van Thi?n ^ hudng chinh da dugc phan tich lua chpn la nhiet dp, tdc dp tdc nhdn sdy vd tdc dp vdng quay cua thimg chua lieu den chat lugng sdn pham va hieu suat qua trinh tach am I VAT LIEU VA PHlTONG PHAP NGHIEN ClTU Vgt lifu nghien ctru: Nguyen lieu toi sii dung cho nghien cuu dugc trdng va thu hoach vdo thdng gieng ndra 2009 tai huyen Kinh Mdn - tinh Hai Duong Doi tu^ng nghien cdu Cac thdng sd cua qua trinh say bam nhiet kieu ddng cd anh hudng den chdt lugng sdn phdm toi vd hidu sudt tdch am gdm: Nhiet dd, tdc dp tdc nhan say vd sd vong quay cua thung chua lieu Chdt lugng toi thai lat sau sdy: Ham lugng tinh dau tdi so vdi nguyen lidu ban dau (0,39%, [6]); Chat lugng cdm quan cua tdi thdng qua mui hdng dgc tnmg va mui khet dnh hudng cua nhi?t dp va qua trinh oxy hod; Hieu sudt tach dm dugc danh gia bang he sd SMER (kgHiO/kWh) Phuffngphdp nghien ciiru 3.1 Phuong phdp thuc nghiem a) Md hinh thiel bi sdy bam nhi^t idiu ddng: Hinh 1: Sa dd ngt^en ly thiet bi sdy bcem nhiet kieu ihiing quay Md hinh thiet bi sdy bam nhiet kidu thimg quay (hinhl) so vdi cac md hinh thidt bi sdy bom nhiet tTnh khdc [4], [5], da dugc bd sung cdc gidi phdp: Thung quay chua vat lieu sdy thay cho ket cdu khay chua lieu kidu budng sdy TAP CHi CONG NGHIEP NONG THON - SO - 2011 35 3s KHOA HOC - CONG NGH$ tinh; Thidt bi ldm ngudi ^c nhdn sdy trudc di qua thi6t bi bay hoi de lam Ignh tdch dm la gidi phap ndng cao hieu suat tdch dm nhd tan dung su chenh lech nhiet dp giiia mdi trudng vdi nhi?t dp tac nhdn say Thong sd ky thudt chinh: May nen (7) 0,75 kW/3 fa/220V/50Hz sii dung tdc nhan lanh R22; Gidn bay hoi (5) cdng sudt nhiet Qbh = 2,1 kW; Gidn ngung tu (8) cong sudt nhiet Qnt = 3,0 kW; Gian lam ngupi (2) cdng suit nhiet Qln = 1,5 kW; Qugt tudn hodn tac nhdn sdy (9) 120W/lfa/220V/50Hz; Dpng CO thimg quay (13): 90W/Ifa/220V/50Hz; Bom nudc gidi nhiet (1) 25W/lfa/220V/50Hz; Quat thap giai nhiet (4) 15W/lfa/220V/50Hz; Thiing quay (12) cd dudng kinh D400, dp ddi L800; Cdc thidt bi khdc: Thdp gidi nhiet nudc (3); Van tidt luu (6); Kinh kidm tra ga (14); Khay tach nudc ngung (10); Phidn lpc (11); b) Diiu khiin cdc thong sd cua qud trinh sdy: - Didu khidn nhidt dp: Sensor cam ung tin hi?u nhift dp St dang sd (bdng tin hidu mmA) dugc dua ve bp PLC trung tam, dugc dgt trudc thiing quay tren hanh trinh tuan hoan cua dong tdc nhan say Khi nhiet dp vugt gia tri cai dgt thi bp dieu khien tdc dOng ldnh cho co cdu chap hdnh Id bom (1) vd qugt (4) hoat dpng dd thai nhift ngodi mdi trudng, ddng thdi lam ngupi tac nhan say trudc qud trinh ldm lanh tdch drn Mien gidi hgn didu khien nhiet dp tdc nhan say t = 40 - 500C (la ket qud cua cac nghien ciiu don yeu td da xdc dinh) - Dieu khien tdc dp tac nhdn sdy: bdng bidn tan de thay ddi toe dp vong quay ciia quat ly tam (9), chi thi gid tri tdc dp tdc nhan sdy bdng mdy tdc dp gio (ra/s), tuong irng vdi gid tri can cdi ddt cua tdc dp tdc nhan say dugc ddnh ddu trdn num dieu chinh cua bidn tdn Midn gidi ban dieu khien tdc dp tdc nhan sdy to = 0,6 - 1,0 m/s (la ket qud ciia cdc nghien ciiu don ydu td da xdc dinh) - Dieu khidn tdc dp quay cua thung chua lifu: bdng bien tan de thay ddi tdc dp vong quay cua dpng CO thung (13), chi thi gia tri tdc dp vong quay cua thiing chiia lieu bdng may tdc dp vdng, tuong ung vdi gia tri cdn cdi dgt cua toe dp vdng quay cua thimg dugc ddnh dau trdn 36 niim dieu chinh cua bidn tdn Mien gidi han didu khien vong quay thimg tir n = 10 - 15v/phiit (Id kdt qud cua cac nghien cuu don ydu to d3 xdc dinh) c) Tien hdnh thi nghiem Quy trinh xir ly nguyen lifu tien say so chl, tdi dugc thdi lat ddy 2rara vd xii ly ngam nudc pha hod chat Na2S205 vdi hdm lugng 2g/lit phiit Nguyen lieu dugc can trudc va sau xu ly vdi khdi lugng mau say cho moi thi nghidm la 5000g Tidn hanh thi nghifm theo md hinh quy hogch thuc nghiem, theo ddi vd thdng kd so lifu Gia tri SMER dugc tinh trung binh qud trinh sdy cho moi thi nghiera, thdi diem tinh tir dp dra ban diu ciia nguyen lieu wj = 65% den dgt dp dm cu6i Wi 10% Cdc mau thi nghidm dugc ky hieu theo md so de cap nhdt so lieu sau phdn tich chat lugng 3.2 Phuang phdp ddnh gia chat lugng Xdc dinh hara lugng tinh dau: Hdm lugng tinh ddu dugc xdc dinh tren bO Clevenger d>l Phuong phap cani quan: bang phuong phdp phdn tich md td (sensory profile) dugc su dung nhdm xdc dinh su thay ddi ciia cdc tinh chat cam quan dgc tnmg cua san pham qua trinh sdy Cdc budc tien hanh bao gdm: Lua chpn hpi ddng, Xay dung thudt'ngii, Hudn luyfn hpi ddng vd Danh gia san pham Hpi dong sau lua chpn vdi ky thuat vidn chuyen nganh cdng nghf thuc phdm, dugc huan luyfn budi, moi budi 30 phiit, ldo cd mpt buoi xdc dinh va nit gpn thuat ngii tren chi tidu mui cua sdn phdm (mui hang vd miii khet), buoi hudn luyen danh gid cudng dp cac tinh chat tdi sdy Ket qua phdn tich md td dugc cho theo thang diem rdi rgc (1 diem-7 diein) 3.3 Phuang phdp quy hoach th\rc nghifm vd xd ly sd lieu - Sir dung quy hogch true giao ddi xung theo phuong phap ciia Box -Wilson [3], cho yeu to: nhiet dp tac nhan sdy (Xi), tdc dp tdc nhan sdy (X2) va sd vdng quay cua thimg chira lieu (Xj), mdi yeu td tidn hdnh tgi miic (-a,-l, 0, +1, +a), vdi a=l,215 Md hinh thuc nghifm gdml6 thi nghiem, do: thi nghifm tgi nhan (quy TAP CHi CONG NGHIEP NONG THON - S6 - 2011 KHOA HOC hogch todn phdn 23), thi nghidm tai diem (2 thi nghidm cho moi bidn) va thi nghifm ldp tai tdm, vdi hdm muc tieu: Ham lugng tinh diu (Yi), miii hang (Y2), mui khet (Y3) va he so SMER(Y4) - Xu ly bang phdn mem thdng ke DesignExpert 7.1 (Stat-Ease, Inc., Miimeapolis, USA), de phan tich cac he so hdi quy, bd mdt dap ling va tdi uu hda vdi thudt toan hara raong dgi [10] 3.4 Thiet bi su dung khdc Thiet bi phuc vu xu ly raau vd phdn tich cac chi so hod ly: May dd dm nhaiih Adam AMB 310 (Anh); Bp chung cdt Clevender, d>l - Dung cu va thiet bi khdc: Thiet bi tdc dp gid testo 445 (Due); va cdc dung cy khdc nhu can phan tich, can dia II KtT QUA vA THAO LUAN a) Anh hirdng cua nhi^t dp, toe dg tdc nhdn say vd so vong quay din ch&t lugtng sdn pham toi vd hi^u suit tdch am Kkt qud xir Iy sd lifu dd xdc dinh dugc cdc hdm muc tieu tuong iing, bieu didn bdng md hinh bdc 2: Yi = 0,36 - 0,034Xi - 0,006X2 - 0,011X3 ^ 0,019X1X2 - 0,022X1X3 + 0,0006X2X3 - 0,025X,2 0,029X22-0,028X32 Y2 = 4.53 - 0,33X, - 0,11X2 - 0,082X3 f 0,24X,X2 - 0,13X1X3 - 0,069X2X3 - 0,20X12 0,42X22-0,41X32 Y3 = 1,22 + 0,39X1 + 0,11X2 + 0,33X3 0,008X1X2 + 0.28X1X3 + 0,08X2X3 + 0,29X12 + 0,21X22 + 0.29X32 Y4 = 0.72 + 0,037X| + 0,012X2 + 0,021X3 + 0,005X1X2 + 0,01X1X3 - 0,003X2X3 - 0.01X,20,014X22 + 0,003X32 Ddng thdi bieu dien dugc raiic dd dnh hudng cua timg yeu to X|- nhift dp tdc nhdn sdy (A); X2- toe dd tdc nhdn sdy (B); X3- tdc dp vdng quay (C), cdc yeu to khdc gitt d miic trung tara, den cac hdm muc tidu (Hmh 2.a, 2.b, 2.C, 2.d).^ Tir ket qua trdn cho thay: - Ham lugng tinh ddu tdi chiu dnh hudng manh bdi nhift dp tdc nhan say, tidp d^n Id sd vong quay va tdc dp tac nhdn sdy, theo xu hudng t^ if nghich Quy lu^it ndy Id ph^ hgp vd CO sd khoa hpc, tinh dau tdi Id mOt hgp chat de bay hoi rad dpng luc cua qud trinh ludn gia - C6NG NGH£ tdng theo chidu tang cua nhift dd bay hoi, tan suit dao trpn vat lifu vd luu Iugng ciia ddng tac nhan say Trong dd, nhift dO la yeu to anh hudng true tiep den qua trinh bay hoi Id didu de hidu Tuy vay hai ydu td lgi thi sd vong quay cd anh hudng mgnh hon den xu hudng gidm ham lugng tinh dau tdi so vdi tdc tac nhdn sdy, cd the qua trinh say bom nhift tuan hodn kin budng sdy nen khd ndng bay hoi cua tinh diu se gidm dan mdi trudng dat den dp bdo hod hdm lugng hoi dau d rapt nhidt dp nhdt dinh Do vdy anh hudng tac dpng cua tdc dp tdc nhan sdy la yeu hon so vdi qua trinh ddo trdn la phii hgp Mdt khac, hdm lugng tinh diu tdi gidm, ngodi ydu to dnh hudng tren cdn tdn thdt mpt phin hoi diu mdi trudng budng sdy dd dugc ngung ty cimg vdi Iugng nudc ngung tai gidn bay hoi de tdch ngodi Tir ddnh gid phan tich cd the dua gidi phdp hgn che miic dp tdn that ham lugng tinh ddu tdi dieu kifn sdn xudt quy md ldn bdng phuang phdp tdch chiet tinh diu tdi tir ngudn nudc ngung Hinh Anh hudng cua cdc yeu td th\fc nghidm cita qua trinh sdy tdi - Miii hdng ciia tdi ciing chiu anh hudng mgnh nhat bdi nhift dO tdc nhan siy, tang nhift dp mui hang cua tdi gidm, tidp theo hai ydu td cdn lai co mdc dp anh hudng gan nhu vd ty If nghich vdi mui hdng cua tdi Vd ban chdt miii hdng cua tdi Id miii d ^ tnmg cua chdt allicin, chat ndy dugc tao sau cu tdi bi pha v5 td bdo qud trinh thai, cdt vd tidp xiic vdi mdi trudng khong md binh thudng vdi tpi nguyen cii thi khdn^ co chdt allicm [1] Nhu vay cd the nhdn xet rdng phan dng tao chdt allicin Id rdt nhgy cdm vdi nhift df cao vd dieu kifn tiep xiic mdi trudng khdng khi, TAP CHf CONG NGHI$P NONG THON • SO • 2011 37 KHOA HOC - CdNG NGHfi hogc tang cudng qud trinh dao trdn thi cdng lam tang khd ndng tdn thdt mui hdng, qud trinh oxy hod vd bay hoi xay mgnh me hon DiSu ndy cho thiy nlu sdy tdi bdng cac phuong phap siy hd thdng thudng thi mirc dp tdn that ham lugng allicin sS ldn han, qua trinh oxy hod dien mdnh lift hon, ddng nghia vdi ham lugng allicin cdng §iam manh - Mui khet cua tdi say cung chiu dnh hudng manh nhat bdi nhiet dp tdc nhdn sdy, tiep den Id sd vdng quay va tdc dp tac nhan say, theo xu hudng ty Id thudn Di§u cd thd dugc ly gidi miii khet la phdn ung dugc tao sau da CO mat ciia chat allicin, thdng thudng bang cam quan thi miii hdng cang giam thi miii khet cdng cd xu hudng tdng Mat khdc nguyen nhan tao miii khet ciia tdi la qua trinh oxy hod va chiu tac dpng dnh hudng manh cua nhift cao vd tin sudt dao trpn vat lieu cdng tang cudng su tiep xiic vdi mdi trudng khdng giau oxy Nhu vgy vdi mdi trudng siy kin co khd ndng hgn che sir gia tdng ndng dp oxy vd miic dp anh hudng ciia tdc dp tac nhdn sdy Qua ket qua nghien cuu thuc nghiem ndy cang khdng dinh gidi phap say kin d nhiet dp thdp cua cdng nghe sdy bom nhift tuan hodn kin cd uu di§m ve tinh cdi thien chdt lugng sdn phim tdi sdy so vdi cdc phuong phdp say thdng thudng Di§u cdn phii hgp vdi nhung nghien cuu da phdt tridn cdng nghf say bom nhiet mdi trudng bidn ddi (MAHPD) ma nhom tdc gia Perera, C O vd cdc cdng su [15] da dua gidi phap thay ddi mdi trudng khdng la tdc nhan sdy bdng mdi trudng tro - He sd SMER cd dnh hudng mgnh nhdt Id nhift dp tdc nhdn sd^, tiSp ddn Id sd vong quay vd toe dp tdc nhan sdy, cac ydu td ndy tang thi hf so SMER cd xu hudng tdng Vdi quy ludt dien bidn Id phii hgp vdi ca sd khoa hoc ciia cdn^ nghe say bom nhift, nhidt dO tang thi dp dm tdc nhdn siy gidm, kdt hgp vdi tang sd vong quay dd tgo dOng lye qua trinh tdch dm cd hifu qud han vd ngugc lai K6t qud nghien ciiu thuc nghifm cQng cho thdy tdc dung cua qud trinh sdy dpng dd ndng cao hifu suit sdy va cd dnh hudng manh ban tdc dp tac nhdn sdy, dieu ndy Id miin gidi han cua tdc dp tdc nhdn say dd dugc thiet kd phii hgp vdi tdi nhift 38 TAP cua bom nhift nen khd nang bien thidn la khdng ldn b) Ket qud tSi iru hoa qud trinh sdy toi bang cong nghe sdy bffm nhiet kiiu dpng Myc tidu toi uu hod qud trinh say tdi dugc tien hanh cho thu dugc tdi khd vdi chit lugng san phdm vd hifu qua siy cao nhit Kk qud tidn hanh gidi bai toan tdi uu hoa bdng each chap myc tidu theo thudt todn "ham mong dgi" dugc dua bdi Derringer va Suich [9] vdi cac dieu kifn rang budc: - Nhiet tac nhan sdy: 45 - SCO (H§ s6 quan tipng; 5) - Toe dp tac nhan sdy: 0,6 - Im/s (H§ so quan trpng: 4) - So vong quay: 10-15 vong/phiit (H^ s6 quan trpng: 4) - H ^ lirpng tinh d^u: c\rc d^i (0,39%) (H? s6 quan trgng: 5) - Miii hang cua tdi: circ d^i (7 dilm) (Hf s6 quan trpng: 5) - Mill khet ciia t6i: c\ic tifiu (1 diem) (H? so quan trpng: 5) - H? s6 SMER: circ dgi (lkgH20/kWh) {Hf s6 quan trpng; 3) Kdt qud tdi uu hda bang phan mdm Design-Expert 7.1 nhu sau: nhift dp tdc nhan say 45oC, tdc dp tdc nhan say 0,79m/s, tdc dp vdng quay 12,5 vong/phiit; Khi hdm lupng tinh diu dat 0.364%; miii hang cua tdi 4,54 dilm; mill khet 1,21 didm; he sd SMER 0,72 kgH20/kWh Vdi phuang dn tdi uu thi cac yeu cau ddi vdi yeu td diih hudng deu dat 100% mong mudn, myc tieu vd hdm lupng tinh diu dat 96,2% mong mudn, miii hdng dat 93,5% raong mudn, miii khet dgt 94,6% mong muon, he sd SMER dgt 54.5% mong mudn vd myc tieu chung dgt 88,7% mong mudn (hinh 3) Hinh Mirc dd dap img su mang d^ III K E T L U ^ N Cdng nghf say bora nhift tuin hoan kin kieu thimg quay dng dung dd sdy tdi dgng thai Idt Id mpt gidi phdp cdng nghf cai thifn dugc chat lugng san phdra vd nang cao dugc hifu qua ciia qud trinh sdy Chd dp tdi uu dugc xdc djnh d nhift dp tdc nhan siy 45oC, tdc dp tdc nhdn sdy CHI CONG NGHIEP NONG THON - SO - 2011 KHOA HOC - C O N G NGHE 0,79rn/s, tdc dp vdng quay 12,5 vong/phiit; Khi dd chat lugng san phdm dgt dugc vdi hdra lugng tinh diu 0,364%; Mui hdng ciia tdi 4,54/7 didm; Miii khet 1,21/7 didm; Hf sd SMER 0,72 kgH20/kWh Vdi quy md sdn xuat cdng nghifp irng dung cdng nghf sdy bom nhift tudn hoan kin kidu thimg quay de say tdi thdi lat thi tdc dp vong quay cua thimg chira lifu dugc quy ddi tir ket qua nghien cuu cua rad hinh thuc nghifm vdi (Dudng kinh thung D400, sd vdng quay tdi uu Id 12,5 vdng/phut), tuong dng van tdc ddi cua vat lieu tren mat thimg quay Id: 0,26ra/s TAI LIEU THAM K H A O Heinrich P Koch, Larry D Lawson (2000); Tdi - Khoa hpc va tac dung chiia bfnh (Ngudi dich: Tran Tat Thing); Nha xuat ban Y hpc Ph^m van Tiiy, Nguyin Nguyen An (2005) "Bern nhift siy Ignh va hiit am BK-BSH 18" Tgp chi Khoa hoc & Cong nghf nhift, sd 65 Nguyin Minh Tuyen (2005); Quy hogch thuc nghifm; Nha xuat ban khoa hpc ky thuat Phgm Anh Tuan (2005) "Xay dyng md hinh thyc nghifm say boTn nhift va ket qua thyc nghifm ban dau"; Tap chi Khoa hpc & Cdng nghf nhift, so 62 Phgm Anh Tuan (2006) Bdo cao khoa hpc De tai: "Nghien ciiu cac thdng s6 cua qud ttinh say bdng bcrm nhift cho mot so san pham rau gia vj" Phgm Anh Tuan, Le Nguyen Ducmg, Chu Van Thien, Nguyin Thi Minh Tii (2009); Nghien cuu dnh hudng cua ribift dp say den thdi gian vd chat Iugng ddi vdi mpt so san pham rau qua; Tap chi Khoa hpc & Cdng nghf, so 2/2009 A.E Johnson, H.E Nursten, A.A Williams (1971), Vegetable volatiles : a survey of components identified Part I Chem Ind Conrad O Perera and M.Shafiur Rahman (1997); Heat pump dehumidifier drying of foods Derringer G., Suich R., "Simultaneous optimization of several responses variables", Journal of Quality Technology, 12 (4), (1980), pp 214-219 10 Design-Expert version 7.1, Software for design of experiments, Stat-Ease,'Inc., Minneapolis, USA, 2007 11 J Blanco Castro , J.F Urchuegui a, J.M Corberan, J Gonza'lvez (2005); Optimized design of a heat exchanger for an air-to-water reversible heat pump working with propane (R290) as refiigerant: Modelling analysis and experimental observations 12 M.S So'ylemez (2005); Optimum heat pump in drying systems with waste heat recovery Department of Mechanical Engineering, University of Gaziantep, 27310 Gaziantep, Turkey 13 M Fatouh , M.N Metwally, A.B Helali, M.H Shedid (2005); Herbs drying using a heat pump dryer 14 Mason, R L 1989 Application of heat pumps to drying food products Food Aust 41(12) 15 Perera, C O and Rahman, M S (1997) Heat pump drying Trends Food Sci Technol 8(3) 16 Sosle.V., Raghavan.G and R Kittler (2003) Low- Temperature Drying Using a Versatile Heat Pump Dehumidifier Drying Technology Pham Anh Tuan, Chu Van Thien The drying process of garlic has been carried out on a model of rotary heat pump drying The material studied has been planted and harvested at Kinh Mon, Hai Duong city The factors influenced the drying including drying temperature, speed of drying agent, and speed of drying container were studied The drying process has been performed by factors mentioned above at the limits of 40-50'^ for temperature; 0,6 -1,0 m/s for agent speed and 10 -15 rpm for container speed; and for quality evaluation of dried garlic criteria of essentia] oil content, sensory properties and SMER were the most interested The results showed that criteria all were impacted strongly ordering by drying speed, drying temperature, and drying agent speed, respectively Optimized condition for garlic drying on the model of the rotary heat pump drying determined were as followipgs: drying agent temperature, 45''C; drying agent speed, 0,79m/s; drying speed, 12,5 rpm; at that point, essential oil obtained was reached at 0,364%; the pungent, a characteristic odor of garlic was 4,54 by sensory profile; the burnt, a failure odor of drying process was 1,21 by sensory profile and the SMER was 0,72 kgHzO/kWh TAP CHf CONG NGHIEP NONG T H N - SO - 2011 39