Impact of Emissive Power of Electric Infrared Emiers on ......In contrast, CIR emi9ers usually a9ain...
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To compare tomato peeling performance and product quality under maximum emissive power of different electric emi9ers. Results revealed that the emissive power significantly affected the peeling performance and product quality. The emissive power of electric emi9ers CFTE, PQE, QHM and QTM were found to be 938, 1137, 1083 and 878 W, respecNvely (Figure 6), which were significantly higher than that of previously tested CIR emi9er based on energy intensity. All the electric emi9ers tested in this study achieved acceptable tomato peeling performance in significantly lower residence Nme (≤20 seconds) compared to previously tested CIR emi9ers which required 51 seconds to achieve similar peeling performance. PQE and QTM achieved acceptable peeling performance in residence Nmes ≤ 20 seconds. Among all, PQE had the highest emissive power and achieved the acceptable peeling performance (Figures 1-4) in shortest residence Nme (only 10 seconds). Tomatoes experienced skin burn at residence Nme >25 seconds. All the IR emi9ers tested in this study emi9ed a peak wavelength in medium wavelength emission spectrum (2-4 µm) (Figure 5). Electric IR emi9ers with high emissive power significantly reduced residence Nme to achieve acceptable tomato peeling performance and product quality. The unique feature of electric emi9ers with high emissive power can make them suitable for a broad range of food processing applicaNons, including peeling process. Abstract Background Objective Materials and Methods Results and Discussion Conclusions Sriram Vidyarthi 1 , Ragab Khir 1, 2 , Zhongli Pan 1, 3 1 Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA 2 Department of Agricultural Engineering, Faculty of Agriculture, Suez Canal University, Ismailia, 41522 Egypt 3 Healthy Processed Foods Research Unit, USDA-ARS-WRRC, 800 Buchanan St., Albany, CA 94710, USA Impact of Emissive Power of Electric Infrared Emi9ers on Tomato Peeling Performance UNIVERSITY OF CALIFORNIA Results and Discussion (continued) SchemaNc of IR heaNng system Contact information Dr. Zhongli Pan USDA-ARS-WRRC University of California, Davis Phone: 510-559-5861 Fax: 510-559-5851 E-mail: [email protected] Website: http://research.engineering.ucdavis.edu/panlab/ Acknowledgments The authors would like to thank California Department of Food and Agriculture (CDFA) and California League of Food Processors (CLFP) for supporNng this project. Fig 1. Tomato peeling easiness Fig 2. Tomato peelability Fig 3. Tomato peeling loss Fig 4. Tomato firmness loss Fig 6. Emissive power of emi9ers Emissive power of an IR emi9er is one of the most important factors to determine its suitability for a specific applicaNon. The spectral characterisNcs (distribuNon of radiant energy over wavelength spectrum) are related to emissive power of emi9er, which influence the heat transfer efficiency. Ideally, spectral characterisNcs of emi9er match to the absorpNon characterisNcs of the objects to be heated in order to maximize the absorpNon of IR energy and achieve opNmal heaNng efficiency. Electric emi9ers can produce a wide range of temperature (up to as high as 2500°C), resulNng in generaNon of a wide range of emissive power and wavelength spectrum, which may be suitable for different applicaNons in food processing, including peeling. In contrast, CIR emi9ers usually a9ain lower temperature and emissive power which is preferred in food drying applicaNons because lower emissive power is suitable for controlling the drying rate. However, peeling is a different unit operaNon which requires a rapid heaNng with relaNvely higher IR intensity than drying. A high emissive power will increase the heaNng rate of tomato, resulNng in achieving be9er tomato peeling performance and product quality. Therefore, a comprehensive study is important to understand the effect of emissive power of electric emi9ers on tomato peeling performance. Tomato culNvar: Hz 6410 (Diameter – 50-53 mm) Electric IR emi9ers: CFTE, PQE, QTM and QHM (1000 W, 240 V; WECO InternaNonal Inc., Clio, Michigan, USA) Residence Nmes: 10, 15, 20 and 25s (3 replicates) RotaNon speed: 5 rpm (Constant) Distance between emi9ers: 70 mm (Constant) Experimental Design: Split plot 0 1 2 3 4 5 6 0 5 10 15 20 25 30 Peeling Easiness Scale Residence Time (s) CFTE PQE QTM QHM 0.00 0.05 0.10 0.15 0.20 0.25 0 5 10 15 20 25 30 Skin ABached (cm2/g) Residence Time (s) CFTE PQE QHM QTM USDA maximum permissible peelability (≤0.015 cm 2 /g) 0% 5% 10% 15% 20% 25% 30% 0 5 10 15 20 25 30 Peeling Loss (%) Residence Time (Sec) CFTE PQE QTM QHM -20% 0% 20% 40% 60% 80% 100% 0 5 10 15 20 25 30 Loss in Firmness (%) Residence Time (Sec) CFTE PQE QTM QHM Emi9ers: (a) CFTE (b) PQE (c) QTM (d) QHM 0 5 10 15 20 25 0 1 2 3 4 5 6 7 8 9 10 Spectral RadiaOon Intensity (KW/m 2 -µm) Wavelength, λ (µm) CatalyOc (585 °C) CFTE (602 °C) QTM (825 °C) QHM (769 °C) PQE (643 °C) Fig 5. Spectral characterisNcs of IR emi9ers a c d b Direct contact thermometer a Tomato b Peeled tomatoes (a) Tomato heaNng (b) Emi9er temp measurement Peeling easiness scale Raw tomatoes This study invesNgated the effect of emissive power of electric infrared emi9ers on tomato heaNng rate, tomato peeling performance and final product quality. Four types of electric emi9ers, including ceramic full trough element (CFTE), pillared quartz element (PQE), quartz tungsten medium (QTM) and quartz halogen medium (QHM), were tested based on their ability to produce higher emissive power. The peeling performance of electric emi9ers was compared with that of catalyNc infrared emi9ers (CIR). The high emissive power of these emi9ers increased the heaNng rate of tomato, resulNng in achieving be9er tomato peeling performance and product quality. Electric emi9ers achieved an acceptable tomato peeling performance and product quality in less than 20 seconds of heaNng Nme. PQE achieved the acceptable peeling performance in 10 seconds. However, tomato experienced skin burn with longer heaNng Nme under these emi9ers, which needs to be controlled. 938 1137 1083 878 0 200 400 600 800 1000 1200 CFTE PQE QTM QHM Emissive Power (W) Electric emiters
Transcript of Impact of Emissive Power of Electric Infrared Emiers on ......In contrast, CIR emi9ers usually a9ain...
To compare tomato peeling performance and product quality undermaximumemissivepowerofdifferentelectricemi9ers.
Results revealed that the emissive power significantly affected the peelingperformance and product quality. The emissive power of electric emi9ersCFTE, PQE, QHM and QTM were found to be 938, 1137, 1083 and 878 W,respecNvely(Figure6),whichweresignificantlyhigherthanthatofpreviouslytestedCIRemi9erbasedonenergyintensity.Alltheelectricemi9erstestedinthis study achieved acceptable tomato peeling performance in significantlylower residence Nme (≤20 seconds) compared to previously tested CIRemi9erswhich required 51 seconds to achieve similar peeling performance.PQEandQTMachievedacceptablepeelingperformance inresidenceNmes≤20seconds.Amongall,PQEhadthehighestemissivepowerandachievedtheacceptablepeelingperformance(Figures1-4)inshortestresidenceNme(only10seconds).TomatoesexperiencedskinburnatresidenceNme>25seconds.AlltheIRemi9erstestedinthisstudyemi9edapeakwavelengthinmediumwavelengthemissionspectrum(2-4µm)(Figure5).
Electric IR emi9ers with high emissive power significantly reducedresidence Nme to achieve acceptable tomato peeling performance andproductquality.Theuniquefeatureofelectricemi9erswithhighemissivepower can make them suitable for a broad range of food processingapplicaNons,includingpeelingprocess.
Abstract
Background
Objective
Materials and Methods
Results and Discussion Conclusions
SriramVidyarthi1,RagabKhir1,2,ZhongliPan1,3
1DepartmentofBiologicalandAgriculturalEngineering,UniversityofCalifornia,Davis,OneShieldsAvenue,Davis,CA95616,USA2DepartmentofAgriculturalEngineering,FacultyofAgriculture,SuezCanalUniversity,Ismailia,41522Egypt
3HealthyProcessedFoodsResearchUnit,USDA-ARS-WRRC,800BuchananSt.,Albany,CA94710,USA
ImpactofEmissivePowerofElectricInfraredEmi9ersonTomatoPeelingPerformance
UNIVERSITY OF CALIFORNIA
Results and Discussion (continued)
SchemaNcofIRheaNngsystem
Contact informationDr. Zhongli PanUSDA-ARS-WRRCUniversity of California, DavisPhone: 510-559-5861 Fax: 510-559-5851 E-mail: [email protected]: http://research.engineering.ucdavis.edu/panlab/
Acknowledgments The authors would like to thank California Department of Food andAgriculture (CDFA) and California League of Food Processors (CLFP) forsupporNngthisproject.
Fig1.Tomatopeelingeasiness Fig2.Tomatopeelability
Fig3.Tomatopeelingloss Fig4.Tomatofirmnessloss
Fig6.Emissivepowerofemi9ers
EmissivepowerofanIRemi9erisoneofthemostimportantfactorstodetermine its suitability for a specific applicaNon. The spectralcharacterisNcs (distribuNon of radiant energy over wavelengthspectrum)arerelatedtoemissivepowerofemi9er,whichinfluencetheheat transfer efficiency. Ideally, spectral characterisNcs of emi9ermatch to the absorpNon characterisNcs of the objects to be heated inorder to maximize the absorpNon of IR energy and achieve opNmalheaNng efficiency. Electric emi9ers can produce a wide range oftemperature(uptoashighas2500°C),resulNngingeneraNonofawiderange of emissive power and wavelength spectrum, which may besuitable fordifferentapplicaNons in foodprocessing, includingpeeling.Incontrast,CIRemi9ersusuallya9ainlowertemperatureandemissivepower which is preferred in food drying applicaNons because loweremissive power is suitable for controlling the drying rate. However,peelingisadifferentunitoperaNonwhichrequiresarapidheaNngwithrelaNvely higher IR intensity than drying. A high emissive power willincreasetheheaNngrateoftomato,resulNnginachievingbe9ertomatopeeling performance and product quality. Therefore, a comprehensivestudyisimportanttounderstandtheeffectofemissivepowerofelectricemi9ersontomatopeelingperformance.
TomatoculNvar:Hz6410(Diameter–50-53mm)Electric IR emi9ers: CFTE, PQE, QTM and QHM (1000 W, 240 V; WECOInternaNonalInc.,Clio,Michigan,USA)ResidenceNmes:10,15,20and25s(3replicates)RotaNonspeed:5rpm(Constant)Distancebetweenemi9ers:70mm(Constant)ExperimentalDesign:Splitplot
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ThisstudyinvesNgatedtheeffectofemissivepowerofelectricinfraredemi9ersontomatoheaNngrate,tomatopeelingperformanceandfinalproduct quality. Four types of electric emi9ers, including ceramic fulltroughelement (CFTE),pillaredquartzelement (PQE),quartz tungstenmedium(QTM)andquartzhalogenmedium(QHM),weretestedbasedon their ability to produce higher emissive power. The peelingperformance of electric emi9ers was comparedwith that of catalyNcinfrared emi9ers (CIR). The high emissive power of these emi9ersincreased the heaNng rate of tomato, resulNng in achieving be9ertomato peeling performance and product quality. Electric emi9ersachieved an acceptable tomato peeling performance and productquality in less than 20 seconds of heaNng Nme. PQE achieved theacceptable peeling performance in 10 seconds. However, tomatoexperienced skinburnwith longer heaNngNmeunder these emi9ers,whichneedstobecontrolled.
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