Combined Hot Air-Microwave Drying Methods in Banana Chips Production

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1 Amerin-Eursin J. Agri. & Environ. Si., (8): , ISSN IDOSI Pulitions, DOI:.589/idosi.ejes Comined Hot Air-Mirowve Drying Methods in Bnn Chips Prodution Hmid Tvkolipour nd Leil Zirjni Deprtment of Food Engineering, Szevr Brnh, Islmi Azd University, Szevr, Irn Astrt: Bnns were slied t three thikness (, 5 nd mm) nd treted y three pretretments T, T, T nd T s ontrol smple. Bnn slie dried y omined hot ir-mirowve drying method. Drying prmeters suh s drying rte nd rehydrtion rtio long with qulity ftors suh s olor, sori id nd sugr ontent were evluted. Pretretments inresed drying rte nd deresed drying time. All pretretments hd signifint effet on qulity ftors ut pretretment with % sodium isulphite showed higher qulity ftors exept sori id in omprison with other tretments. Key words: Bnn hips Mirowve ssisted drying Convetion drying Pretretments Asori id INTRODUCTION onventionl hot ir drying method. In mirowve drying method, het trnsmission is ulkily, so moisture removl Bnn is one of the importnt tropil fruits tht re is quik. Also euse onentrted energy of mirowve produed verge of 5 million tons yerly in the world. fields, only -5% of the floor spe is required s The min prt onsumed s fresh nd remining used for ompred to onventionl heting nd drying fility. proessing nd formultion. Bnn hve high In other hnd, it is not eonomil to dry food mterils nutritionl vlue nd it is good soure of energy due to y mirowve only euse mirowve drying is known its high level of strh nd sugr, s well s soure of to results poor qulity produt if not properly pplied. vitmin A nd C, Potssium, lium, sodium nd Mirowve energy produed het internlly in foods mgnesium. therefore its etter pplied to flling rte period where From iologil point of view, nns hve high internl mss trnsfer is dominnt. loss due to dey during hndling nd trnsporttion Mskn () studied on vrious drying methods nd impose high expenses from eonomil point of view. suh s hot ir drying, mirowve nd omined drying of One of the oldest nd developing methods of food slied nn []. The results showed tht drying time in preservtion is drying whih provides n extension of onventionl hot ir method ws longer thn two other shelf life esides protetion produt qulity suh s methods. Also, it ws oserved in high mirowve power nutrient mterils, flvor, rom, olor nd struture. the drying rte ws inresed nd dried nn y Fruits like nn tht hve more sugr need high drying omined method hd light olor nd high rehydrtion temperture nd long time to reh sfe moisture ontent. rtio. Color hnge in mirowve method depended on During drying proess some undesirle retions were mirowve power ut in onvetionl hot ir method ws tke ple used prtil destrution of flvor, olor, higher thn two other methods. Moisture ontent of nutrients nd deresed ulk density nd rehydrtion nn hips fter rehydrtion didn t reh to their initil pity of dried produt. In hot ir drying method due to moisture ontent due to some texture destrution during low het ondutivity of foods het trnsfer to internl drying. Demirl nd Turhn () studied drying prts tke slowly, so drying time will e longer. To solve ehvior of two nns speies (Dwrf Cvendish nd this prolem nd prevent qulity redution in order to Gros Mihel). They used different pretretments suh s: reh n effetive het trnsfer, mirowve will e used sodium isulphte %, sori - itri id mixture.% for drying of foods. Mirowve is rpid method for food nd n untreted smple s ontrol. The results showed drying euse energy trnsmission is different from tht ll pretretments inresed drying rte []. Corresponding Author: Hmid Tvkolipour, Deprtment of Food Engineering, Szevr Brnh, Islmi Azd University, Szevr, Irn. 77

2 Am-Eurs. J. Agri. & Environ. Si., (8): , Dndmrongrk et l.() used pretretments like Moisture Content: Bnn ws peeled, ut to slies nd lnhing, freezing, omined of oth nd ooling. rushed to nn puree.5 g nn puree pled in They studied drying ehvior of treted nns dried in len nd dry plte nd dried until reh to onstnt het pump dryer. It distinguished tht tretments weight in oven t 5 C []. When three onseutive inresed drying rte []. Boudhirou et l. () studied weighting were onstnt, moisture ontent (wet sis) rheologil properties of nn slies were dried y hot ws lulted: ir drying method []. Chu et l. () used het pump dryer for nn drying in two stge nd found if higher X = (M-M ) / M () temperture seleted t eginning then deresed grdully, produt olor nd drying time would e Initil moisture ontent of fresh nn ws otined improved [5]. Some reserhers fous on nn drying.76 ( in dry sis) nd for lnhed smples ws y freezing long with osmoti dehydrtion [6-9]. determined.78 (.76 in dry sis) due to some wter In present reserh nn dried y hot ir drying sorption during lnhing. followed y mirowve drying nd studied influene of pretretments nd different thiknesses nn slies on Comined Hot Air-Mirowve Drying Method: Bnn drying ehvior of nn nd influene of different smples with three thiknesses nd three pretretments in drying prmeters on olor, rehydrtion, sugr nd ddition to ontrol smples first dried y hot ir t 6 C sori id ontents of dried produts. temperture until rehed to ritil moisture ontent.5 kgw/kgs then dried y mirowve oven with W MATERIALS AND METHODS power intensity until rehed to finl moisture ontent kgw/kgs. This power ws seleted euse Ripe nns were purhsed from lol mrket nd smples t higher mirowve power intensity were stored t 5- C during experiments. Bnns were peeled urned. Moisture loss ws reorded every min period y hnd nd ut with shrp knife to, 5 nd mm t hot ir drying method nd in s intervls t mirowve thikness on polyethylene ord. After oven. Moisture ontent s funtion of drying time preprtion, the smples re rndomly divided into lulted y mteril lne: groups nd three pretretments were pplied to smple efore drying nd n untreted smple (T ) ws used s M (-X ) = M (-X ) () ontrol. Pretretments inluding % sodium isulphite (T ), Dried smples were olleted, ooled nd pkged omined lnhing nd % sodium isulphite (T ) nd in polyethylene gs nd stored in dry, ool nd drk omined lnhing nd % sori - itri id (:) ple until qulity ftors mesurements. solution (T ). The detils of eh pretretment were desried s elow: Vitmin C: Determintion of vitmin C ontent performed y, 6 Dihloroindophenol titrtion method []. Control (T ): The smples peeled nd ut to slies of, 5 nd mm thikness then pled into dryer Rehydrtion Rtio: Dried nn hips first weighted diretly without ny pretretment. then immersed in distilled wter until onstnt weight T : The smples peeled nd ut to slies of, 5 nd (out 5 hours) then smples lotted y tissue pper to mm thikness were dipped into % sodium removed exess wter nd weighted gin. Finlly re isulphite solution for min then rinsed in distilled hydrtion rtio ws lulted: wter for s in order to removed ny solution nd slies lotted with tissue pper. RC = Wr /Wd () T : The nn slies were lnhed in oiling wter for min then immeditely ooled in tp wter for Sugr Content (Surose): sugr (surose) ontent min to remove exess het then treted slies lotted determined y Lne Eynon titrtion method []. with tissue pper. T : The nn slies were lnhed like to previous Color Mesurement: Bnn hips olor mesured method then dipped into % sori - itri id efore nd fter drying y Lovind (model F) (:) solution for min nd finlly slies were lotted olorimeter. Three olor index inluding redness (R), with tissue pper. yellowness (Y) nd lueness(b) were mesured y 77

3 Am-Eurs. J. Agri. & Environ. Si., (8): , Lovind nd totl olor index lulted y following eqution. This index distinguish olor hnges during drying proess. Totl olor index = (R Y) /(B Y) () Fresh nn totl olor index ws set s referene for olor hnges during drying proess. Drying Time nd Drying Rte Curves: The drying urve ws skethed s dry sis moisture ontent of nn slie t eh time versus drying time. Drying rte ws lulted y dividing differene of two onseutive moisture ontent y drying time intervl. Drying rte ws skethed versus moisture ontent (dry sis). Sttistil Anlysis: Rndomized omplete lok design ws used for sttistil nlysis. Averge omprison were evluted y Dunn's multiple rnge test. RESULTS AND DISCUSSION Drying Time: Figure showed tht treted smples hd shorter drying time reltive to ontrol smple. In omprison etween pretretments, lnhed nn slie hd shortest drying time. For exmple drying time for reh to finl moisture ontent t smples for ontrol T nd pretretments T, Tnd T in mm thikness were 5, 5, nd min respetively. Smples treted with pretretment T showed % redution in omprison with ontrol smple. In other hnd, nn hips tht produed with pretretments T nd T showed 5% redution reltive to ontrol smple nd 5% redution reltive to smples those treted with T. During lnhing pretretment T some destrution in nn texture mye ourred so used loss of more wter during drying. Chemil tretments with sodium isulphite results texture dmged ut if retention time ws seleted more thn min used moisture ontent (kgw/kgs) v erge of drying 5 moisture ontent(kgw/kgs) 5 time (min) T T T T Fig. : Drying urve for nn slies with mm thikness nd pretretments T, T T, T T T T T verge of drying time pretretments Fig. : Influene of vrious pretretments on drying time mm 5mm mm Fig. : Drying urve for nn slies with,5 nd mm thikness nd (T ) pretretment The results showed tht with inrese of slie thikness drying time inresed t ll of pretretments (Figures, nd 5). For exmple drying time in slies with serious texture destrution.,5 nd mm thikness nd pretretment T were 5, 5 As shown in Figure drying urve t mirowve nd min, respetively. Furthermore results of ANOVA drying stge hd shrp due to higher drying rte in nlysis showed tht effet thiknesses hve signifint mirowve drying reltive to hot ir drying euse het effet on drying time tht presented in Figure 6. produed inside of nn slie therefore het trnsfer y mirowve higher thn onvetion nd ondution het Drying rte: Pretretments inresed drying rte nd trnsmission. ANOVA nlyses showed tht effet of shrp rise oserved in mirowve drying. The highest pretretments hve signifint differene in drying time s drying rte oserved for T followed y T, Tnd ontrol shown in Figure. smple (T ) s shown in Figure 7., 77

4 Am-Eurs. J. Agri. & Environ. Si., (8): , moisture ontent(kgw/kgs) drying rte (kgw/kgs.min) moisture ontent (kgw/kgs) moisture ontent(kgw/kgs) mm 5mm mm v erge of drying drying rte(kgw/kgs/min) mm 5mm mm mm 5mm mm verge of drying time thikness moisture ontent (kgw/kgs) 5 v erge of vitmin C ontent (mg/) mm 5mm mm Fig. : Drying urve for nn slies with,5 nd mm Fig. 8: Drying rte urve of nn slie with, 5 nd thikness nd pretretment T mm thikness nd pretretment T Fig. 5: Drying urve for nn slies with,5 nd mm thikness nd pretretment T Fig. 6: Influene of nn slie thikness on drying time T T T verge of vitmin C pretretments Fig. 9: Influene of pretretments on vitmin C ontent As oserved from drying rte urves in Figure 7 in oth drying methods (hot ir nd mirowve), onstnt drying period don't oserved nd drying ourred only in flling rte period. Also shrinkge nd se hrdening due to rpid strh geltiniztion used rrier to moisture trnsfer espeilly t lter stges of drying. Also the results showed tht with inresing slie thikness drying rte ws deresed (Fig. 8). Although results of prior reserhes showed tht for mirowve drying method with inresing slie thikness, drying rte ws inresed [, ] ut our results showed tht in mirowve drying stge, inresing of nn slie thikness deresed drying rte due to strh geltiniztion in hot ir drying stge. Qulity Ftors Vitmin C: The results showed tht pretretments hd signifint effet on vitmin C ontent of dried nn. It's vlue for fresh nn ws otined 6.6 mg/g. Among three pretretments T hd most vitmin C ut T T T T T hd lest due to dissolution of sori id in lnhing Fig. 7: Drying rte urve for nn slies with mm wter used more loss of vitmin C s oserved in thikness nd pretretments T, T, T, T Figure 9. 77

5 Am-Eurs. J. Agri. & Environ. Si., (8): ,.5.5 v erge of rehydrtion.5 T T T verge ofrehydrtion v erge of sugr 5 ountent (mg/) 5 pretretments Fig. : Influene of pretretments on rehydrtion rtio T T T verge ofsugr v erge of olor. index.. pretretments Fig. : Influene of pretretments on sugr ontent d Color: Visul oservtion of dried produt reveled effet of pretretments on nn slie olor. Fresh Bnn looking like white yellowish ut during drying proess developed yellow rownish olor in nn slie. Under the sme ondition, treted smples exhiited less disolortion reltive to untreted smples. In ddition pretretment T used minimum disolortion in omprison of other pretretments s shown in Figurer. CONCLUSIONS Bnn slies dried with omined hot ir-mirowve finish drying y vrious pretretments. Chemil ftors suh s totl sugr nd sori id nd physil ftors suh s moisture ontent, olor nd rehydrtion rtio of dried smple were determined. Drying rte urve showed ll tretment fll in flling rte period thus mirowve ws suitle for finish drying. All pretretments hd signifint effet on qulity ftors ut pretretment with % sodium isulphite showed higher qulity ftors exept sori id in omprison to other pretretments. Nomenlture: B Blueness - M Initil weight of nn slie g M Finl weight of nn slie g R Redness - RC Rehydrtion pity Ti T T T T Control smple - verge ofolor index T % sodium isulphte pretretments T Blnhing- % sodium isulphte Fig. : Influene of pretretments on olor index T Blnhing-% sori nd itri id Wr Finl weight fter rehydrtion g Rehydrtion Rtio: The results showed tht Wd Dried smple weight g pretretments hd signifint effet on rehydrtion rtio X Initil moisture ontent (dry sis) of dried nn. Between pretretments T hd the most X Moisture ontent t eh time (dry sis) rehydrtion rtio ut none smple rehed to initil Y Yellowness - moisture ontent (Fig. ). REFERENCES Sugr Content (Surose): The results showed tht pretretments hd signifint effet on the sugr ontent. Mskn, M.,. Mirowve/ir nd mirowve of dried nn. Sugr ontent of fresh nn ws finish drying of nn. Journl of Food Engineering, mesured out.6 mg/g. Among three : pretretments, lnhing (T, T ) redued sugr ontent. Demirl, D. nd M. Turhn,. Air-drying ehvior reltive to other pretretments due to dissolution of sugr of Dwrf Cvendish nd Gros Mihel nn in oiling wter during lnhing (Fig. ). slies.journl of Food Engineering, 59:

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