EVALUATION OF THE USE OF THE SOLAR DRYER IN THE DRYING OF MINT AND PARSLEY LEAVES 1

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1 EVALUATION OF THE USE OF THE SOLAR DRYER IN THE DRYING OF MINT AND PARSLEY LEAVES 1 J. D. A. de Oliveir 2, K. S. M de Sous 3, J. L. B. d Silv 4, J. F. d Cruz Neto 5, F. A. C. Lins 6, D. G. Gomes 7 SUMMARY: the ojective is to evlute the inetics of drying of leves of mint nd prsley, dehydrted in solr dryer exposed directly to the sun nd djust the mthemticl models of Pge, Newton, Thompson, Henderson nd Pis, Midilli, Two-term nd Approximtion of Diffusion to the experimentl dt otined nd to chrcterize the two smples studied, regrding prmeters of wter content, totl solids, wter ctivity nd color (L*, * nd *). The dryer is mde of wood, on the top of the dryer there is glss sheet for the entrnce of the solr rys. During the drying of the leves the solr dryer ws exposed directly to the sun, these dt eing used to determine the drying inetics. The wter content nd totl solids were determined y iln drying t 105 ± 1 C, the wter ctivity ws determined y direct mesurement in Aqul meter nd the color ws determined y direct reding in the smple using spectrophotometer. Anlyzing the results it ws verified tht the solr dryer hd n internl temperture higher thn the externl temperture in the drying of mint nd prsley, otining the mximum vlue t 14 hours, nd tht the drying inetics of the leves cn e represented y the Midilli model with good precision. KEYWORDS: Vegetles, mthemticl models, solr drying. AVALIAÇÃO DO USO DO SECADOR SOLAR NA SECAGEM DE FOLHAS DE HORTELÃ E SALSA RESUMO: ojetivou-se vlir cinétic de secgem de folhs de hortelã e sls, desidrtds em secdor solr exposto diretmente o sol e justr os modelos mtemáticos de Pge, Newton, 1 UNIVERSIDADE FEDERAL RURAL DE PERNAMBUCO UFRPE; 2 Doutorndo em Engenhri Agrícol PGEA/UFRPE. Depto. Engenhri Agrícol, UFRPE. Av. D. Mnoel de Medeiros, SN; Dois Irmãos, Recife, PE; CEP: Recife PE. E-mil: josediorgenes@gmil.com; 3 Prof. Doutor em Engenhri Agrícol: Processmento e Armzenmento em Produtos Agrícols, UNIVASF Petrolin. E-mil: rlsmelo@gmil.com; 4 Doutorndo em Engenhri Agrícol PGEA/UFRPE, Recife PE. E-mil: jhonlennoigt@hotmil.com; 5 Doutorndo em Engenhri Agrícol PGEA/UFRPE, Recife PE. E-mil: zenetto.gronomi@gmil.com; 6 Mestrndo em Engenhri Agrícol PGEA/UFRPE, Recife PE. E-mil: frederico_cl@hotmil.com; 7 Doutorndo em Engenhri Agrícol PGEA/UFRPE, Recife PE. E-mil: dnilogro.dg@gmil.com.

2 J. D. A. de Oliveir et l. Thompson, Henderson e Pis, Midilli, Dois termos e Aproximção d difusão os ddos experimentis otidos e crcterizr s dus mostrs estudds, qunto os prâmetros de teor de águ, sólidos totis, tividde de águ e cor (L*, * e *). O secdor é feito de mdeir, n prte superior do secdor há um plc de vidro pr entrd dos rios solres. Durnte secgem ds folhs o secdor solr ficou exposto diretmente o sol, sendo estes ddos utilizdos pr se determinr s cinétics de secgem. O teor de águ e os sólidos totis form determindos por secgem em estuf à tempertur de 105 ± 1 C, tividde de águ foi determind por medid diret em medidor Aqul e cor foi determind por leitur diret n mostr utilizndo-se espectrofotômetro. Anlisndo os resultdos verificou-se que o secdor solr presentou um tempertur intern mior que tempertur extern n secgem de hortelã e sls, otendo o vlor máximo às 14 hors, e que cinétic de secgem ds folhs pode ser representd pelo modelo Midilli com ótim precisão. PALAVRAS-CHAVE: Hortliçs, modelos mtemáticos, secgem solr. INTRODUCTION Vegetle consumption hs een incresing, s well s consumers demnd; therey there is need to mintin its yerly supply in dequte quntity nd qulity, free of preservtives (Gulerto et l., 2009). These vegetles hve een grown in the lst yers y fmily frmers in order to supply in ntur products for supermrets, street mrets, vegetle stnds nd resturnts throughout the region. However, once hrvested, culinry hers my decrese in qulity due to oth mreting dely or y the lc of conservtion methods (Crvlho et l., 2010). One lterntive which cn e implemented, for the smll producers, in order to dd vlue to the spice nd eliminte overproduction wste would e the drying of plnt mterils for posterior selling. Drying is the process used to ensure qulity nd stility, considering tht the decrese in wter content reduces iologicl ctivity nd physicl-chemicl chnges, which occur during storge (Ullmnn et l., 2010). Advntges of the drying process re prcticlity, low costs nd reduction of trnsport volume, while incresing shelf life nd eeping the plnts fresh nd helthy during storge (Recci et l., 2012). Agriculturl commodities drying cn e performed in two wys: nturl or rtificil. Solr dryer involves the solr energy hrnessing, which is free nd renewle. Furthermore, it

3 IV INOVAGRI Interntionl Meeting, 2017 presents low opertion costs, no need of specilized lor, protection ginst insects nd dust nd it cn e uilt in the frm, thus, ddressing smll producers (Mrtins et l., 2002; Togrul & Pehlivn, 2002). Severl reserchers (Sles & Suzui, 2013; Sntos & Sles, 2014; Amnlou et l., 2015; Mendonç et l., 2015) used solr dryer, highlighting its importnce nd efficiency. Therefore, the im of this study ws to evlute nd uild drying inetics of mint nd prsley leves solr drying in solr dryer exposed to sunlight. MATERIAL AND METHODS The study ws crried out in Food Technology Lortory of the Acdemic Unity of Development Technology from the Federl University of Cmpin Grnde (UFCG), Cmpus Sumé nd in the Agriculturl Commodities Storge nd Processing Lortory (LAPPA) of the Agriculturl Engineering Deprtment from Cmpin Grnde. Leves of mint (Menth x villos) nd prsley (Petroselinum crispum Mill.) plnts were ten to the Food Technology Lortory where we performed the removl of ny dmged or sic leves, other plnt prts nd foreign mterils. Leves were wshed in running wter to remove surfce dirt, followed y immersion in sodium hypochlorite solution (100 ppm). Susequently, leves were rewshed in running wter to remove solution excess, nd plced in stinless steel trys nd exposed to ir for surfce wter evportion. The dryer is mde of wood (Figure 1), presenting glss plte on top in order to llow solr rdition to enter the system, nd contins two pillrs in the c so tht the dryer lens forwrd. The dryer is 70-cm long, 47.2-cm wide nd 18-cm high. The products were rrnged in trys over mesh. Prior to the solr drying process, lef wter content ws determined ccording to the methodology descried in the Adolfo Lutz Institute Mnul (Lutz, 2008), in which the smples, in triplictes, were plced into n oven t 105 ± 1 C, until reching constnt weight. Leves which were dehydrted in the solr dryer were weighted in semi-nlyticl lnce (precision: ± 0.01 g), plced into screened sets nd ten to the solr dryer fterwrds. Dehydrted smples were withdrwn nd plced into desicctor until room temperture ws reched. Susequently, the smples were pced into low-density polyethylene gs, closed using seler. During mint nd prsley leves drying process, the solr dryer ws directly exposed to sunlight, using these dt to determine drying inetics. Dt of drying inetics were otined

4 J. D. A. de Oliveir et l. weighting the trys with the smples, during drying events until constnt weight ws reched, in regulr intervls. After dt collection, vlues of moisture rtio were clculted (Eqution 01). where, RX moisture rtio (dimensionless) X moisture content (% dry sis) Xe equilirium wter content (% dry sis) X0 initil moisture content (% dry sis) RX = X S 1 X 0 X e (1) Mthemticl models from Tle 1 were fitted to experimentl dt from the solr drying process of dehydrted leves, using Sttistic 5.0 softwre y nlyzing them through non-liner regression (Qusi-Newton method). In order to evlute the model tht produced the est results, coefficient of determintion (R 2 ) nd root-men-squre devition (Eqution 02) were used s prmeters. where, RMSD root-men-squre devition RXpred model-predicted moisture rtio RXexp experimentl moisture rtio n numer of oservtions RMSD = (RX pred - RX exp ) 2 n Wter content nd totl solids were oven dried t 105 ± 1 C until reching constnt weight, expressed in percentge (%), ccording to the method descried in the Adolfo Lutz Institute Mnul (Lutz, 2008). Wter ctivity ws determined through direct mesurements using Aqul, model 3TE, mnufctured y Decgon Devices t the temperture of 25 C. Color ws determined y direct reding of the smple using spectrophotometer MiniScn HunterL XE Plus, with Ciel color system. The device, equipped with illuminnt D65/10, ws clirted with stndrd white nd lc clirtion pltes (X = 80.5, Y = 85.3, Z = 90.0), in ccordnce with mnufcturer s instructions. The following prmeters were determined: L* which represents the luminosity, white (0) to lc (100) trnsition; * which represents green (-*) to red (+*); nd *, lue (-*) to yellow (+*) trnsition. (2)

5 IV INOVAGRI Interntionl Meeting, 2017 RESULTS AND DISCUSSION It cn e depicted from Figure 2 the grphic of moisture rtio (dimensionless) s function of drying time (min). Anlyzing the figure, there hs een greter weight loss for mint smples in the period from 0 to 200 minutes, then the weight ws prcticlly stle until 300 minutes. On the other hnd, prsley smples reched their stility t 360 minutes, confirming tht they hve lost wter slowly thn mint leves. Tle 2 illustrtes physicl-chemicl prmeters of mint nd prsley leves, respectively, where lef wter content men vlue for mint ws % nd totl solids ws %, while for prsley leves those vlues were % nd %, respectively. These results show tht oth products re perishle, where drying process turns out to e essentil for lef conservtion. Oserving luminosity (L*), red intensity (*) nd yellow intensity (*) vlues of dried smples, it ws verified tht the negtive vlue of the prmeter * indictes green s the min lef color nd prmeter * indictes yellow for mint leves. However, for prsley smples, it ws verified tht the positive vlue of the prmeter * indictes red s the min lef color nd, for * prmeter, yellow. According to Gsprin et l. (2014), when studying peppermint (Menth x Piperit. L) lef drying in fixed ed dryer, oserved luminosity (L*) of 36.59, red intensity (*) of 0.66 nd yellow intensity (*) of 7.96 t the temperture of 50 ºC nd wind speed of 0.5 m s -1. Tles 3 nd 4 show the vlues for Pge, Newton, Thompsom, Henderson nd Pis, Midilli, Two-term nd Diffusion pproximtion models, fitted to drying inetics experimentl dt of oth leves, the coefficients of determintion (R 2 ) nd the root-men-squre devition (RMSD). It ws oserved tht some of models presented coefficients of determintion (R 2 ) greter thn According to the vlues of coefficients of determintion (R 2 ) nd RMSD, the mthemticl model which presented the est result for oth mint nd prsley drying ws Midilli s model, with the following vlues: R 2 = nd , nd RMSD = nd , respectively. Seed (2010) verified R 2 vlues greter thn 0.99 when fitting Diffusion Approximtion, Midilli nd Pge model to dt from the drying of Hiiscus sdriff L. in solr dryer. Reis et l. (2011), studying mthemticl modelling of Cumri do Prá pepper, used severl mthemticl models; however, they concluded tht Midilli s model ws the est fit for experimentl dt, with vlues of R 2 greter thn 0.99.

6 J. D. A. de Oliveir et l. CONCLUSION Most of mthemticl models successfully represented drying inetics of mint nd prsley in solr dryer with coefficients of determintion (R 2 ) greter thn 0.90 nd low vlues of root-men-squre devition (RMSD). Among the models fitted to the drying inetics dt of mint nd prsley leves in solr dryer, Midilli s eqution presented the greter vlues of coefficient of determintion nd the lowest root-men-squre devitions. BIBLIOGRAPHIC REFERENCES AMANLOU, Y.; HASHJIN, T.; GHOBADIAN, B.; NAJAFI, G. Mthemticl modelling of thin-lyer solr drying for yrrow, corinder nd hollyhoc. Interntionl Journl of Food Engineering. v.11, n.5, p , CARVALHO, L. M. COSTA, J. A. M. CARNELOSSI, M. A. G. (2010). Qulidde em plnts medicinis. Emrp Tuleiros Costeiros. Disponível em: Acesso em: 10 de jun GASPARIN, P.P. ALVES, N.C.C. CHRIST, D. COELHO, S.R.M. Qulidde de folhs e rendimento de óleo essencil em hortelã piment (Menth x Piperit L.) sumetid o processo de secgem em secdor de leito fixo. Revist Brsileir Plnts Medicinis. v.16, n.2, p , 2014.GUALBERTO, R.; OLIVEIRA, P. S. R.; GUIMARÃES, A. M. Adptilidde e 78 estilidde fenotípic de cultivres de lfce do grupo cresp em cultivo hidropônico. Horticultur Brsileir. v.27, n.1, p.7-11, LUTZ, I. A. Métodos físico-químicos pr nálise de limentos. IV. ed. São Pulo: ANVISA, p. MARTINS, R. R.; FRANCO, J. B. R. O.; GOMES, P. A. M.; FRANSOZI, J. F. S.; PORTO, C. D. Secdor de grãos com uso de energi solr. Revist Agroecológic e Desenvolvimento Rurl Sustentável. v.3, n.1, p.29-35, MENDONÇA, A. P.; SAMPAIO, P. T. B.; ALMEIDA, F. A. C.; FERREIRA, R. F.; NOVAIS, J. M. Determinção ds curvs de secgem ds sementes de ndiro em secdor solr. Revist Brsileir de Engenhri Agrícol e Amientl. v.19, n.4, p , 2015.

7 IV INOVAGRI Interntionl Meeting, 2017 RECCI, M. R.; BATTISTI. J. F.; SCHMIDT, C. A. P. Secdor solr: Processo de desidrtção de fruts com diferentes trtmentos osmóticos. Cdernos de groecologi. v.7, n.1, p.1-4, REIS, R. C.; BARBOSA, L. S.; LIMA, M.L.; REIS, J. S.; DEVILLA, I. A.; ASCHERI, D. P. R. Modelgem mtemátic d secgem d piment Cumri do Prá. Revist Brsileir de Engenhri Agrícol e Amientl, v.15, n.4, p , SAEED, I. E. Solr drying of Roselle (Hiiscus sdriff L.): mthemticl modelling, drying experiments, nd effects of the drying conditions. Agriculturl Engineering Interntionl: the CIGR Journl. v.12, n.3, p , SALES, J.H; SUZUKI, A. T. Sistem Verticl de Secgem Solr. Revist Geintec (Gestão, Inovção e Tecnologis). v.3, p.1-13, SANTOS, E. C.; SALES, J. H. O. Secdor Verticl Solr pr Amêndos de Ccu. Revist Geintec (Gestão, Inovção e Tecnologis). v.4, n.5, p , TOGRUL, I. T.; PEHLIVAN, D. Mthemticl modelling of solr drying of pricots in thin lyers. Journl of Food Engineering. v.55, n.3, p , ULLMANN, R.; RESENDE, O.; SALES, J.F.; CHAVES, T. H. Qulidde ds sementes de pinhão mnso sumetids à secgem rtificil. Revist Ciênci Agronômic. v.41, n.3, p , Tle 1. Mthemticl models to descrie the process of drying mint nd prsley. MODEL EQUATION Pge RX = exp(-.t n ) Newton RX = exp (-t) Thompson RX = exp((--( 2 +4t) 0,5 )2.) Henderson e Pis RX = exp(-t) Midilli RX =.exp(-.t n ) +.t Two-term RX =.exp(-0.t)+.exp(-1.t) Diffusion Approximtion RX = exp(-t) + (1 - ) exp(-t) where, RX moisture content (dimensionless),, 0, 1 drying coefficients (s -1 );,, c e n model constnts.

8 J. D. A. de Oliveir et l. Figure 1. Imge of the solr dryer. 1,0 0,8 0,6 Mint Prsley RU 0,4 0,2 0, Time (min) Figure 2. Moisture rtio grph of mint nd prsley leves. Tle 2. Men vlues of the physicl-chemicl prmeters of mint nd prsley leves. Prmeters Men ± Stndrd devition Mint Prsley Wter content (%.u.) ± ± 0.11 Totl solids (%) ± ± 0.11 Wter ctivity (w) ± ± Luminosity (L*) ± ± Red intensity (*) ± ± 0.03 Yellow intensity (*) ± ± 0.172

9 IV INOVAGRI Interntionl Meeting, 2017 Tle 3. Vlues of prmeters, coefficients of determintion (R²) nd the root-men-squre devition (RMSD) the models studied (mint). Model Prmeters R 2 DQM n Pge Newton Thompson Henderson e Pis Midilli Two-term Diffusion Approximtion o Tle 4. Vlues of prmeters, coefficients of determintion (R²) nd the root-men-squre devition (RMSD) the models studied (prsley). Model Prmeters R 2 DQM n Pge Newton Thompson Henderson e Pis Midilli Two-term Diffusion Approximtion o