Freeze Drying Kinetics of Persimmon Puree

Öz

his study was intended to determine the drying kinetics of persimmon puree in a freeze drier.Experimental drying data were fitted to theoretical (Fick’s Law of Diffusion) and ten well-knownempirical thin layer drying models. In addition, the effective moisture diffusivity and color changesdepending on the drying time were determined. The criteria considered for selecting the most suitablemodel were to obtain the highest R2and lowest RMSE, and F2values. Depending on these criteria,Logarithmic model (R2=0.994, RMSE=0.0250 and F2=0.0009) was chosen to estimate the moisture ratioof persimmon puree during the drying process with a great accuracy. The effective moisture diffusivity(Deff) of freeze dried persimmon puree was calculated by using the Fick’s Law of diffusion model, andit was found to be as 7.302 x10-10m2/s. During the drying operation L* values increased and a* and b*values of persimmon puree decreased with a total amount of color change ('E) of 32.20

Anahtar Kelimeler

• Persimmon
• freeze drying
• thin layer modelling
• effective moisture diffusivity
• color changes

Cennet Elması Püresinin Dondurarak Kurutma Kinetiğinin Belirlenmesi

Öz

Bu çalıflmada dondurarak kurutulmufl cennet elması püresinin kuruma kineti¤inin belirlenmesihedeflenmifltir. Deneysel veriler teorik (Fick’in Difüzyon Yasası) ve on farklı ince tabaka kurutmamodeli kullanılarak modellenmifltir. Bunlara ek olarak, etkin difüzyon katsayısı ve kuruma zamanınaba¤lı olarak meydana gelen renk de¤iflimi belirlenmifltir. Uygun modelin seçilmesinde en yüksek R2de¤eri ve en düflük RMSE ve F2de¤erleri kriter olarak seçilmifltir. Bu kriterlere ba¤lı olarak, kurumaifllemi boyunca cennet elması püresinin nem oranı de¤erlerini en iyi Logaritmik modelin (R2=0.994,RMSE=0.0250 ve F2=0.0009) temsil etti¤i belirlenmifltir. Cennet elması püresinin etkin difüzyon katsayısı(Deff) Fick’ in Difüzyon Yasası ile belirlenmifl ve 7.302 x10-10m2/s olarak bulunmufltur. Kurutma ifllemiboyunca kuruma zamanına ba¤lı olarak L* de¤erinin arttı¤ı; a* ve b* de¤erlerinin ise azaldı¤ı gözlenmiflve toplam renk de¤iflimi 32.20 olarak hesaplanmıfltır

Anahtar Kelimeler

• Cennet elması
• dondurarak kurutma
• ince tabaka modelleme
• etkin difüzyonkatsayısı
• renk de¤iflimi

Kaynakça

1. Karim MA, Hawlader MNA. 2005. Mathematical modeling and experimental investigation of tropical fruits drying. In. J Heat Mass Tran. 48: 4914-4925 2. Karkacier M. 1998. Trabzon hurmasının (diosyros kaki l.) kimyasal bileflimi üzerine arafltırmalar. Ankara Üniversitesi Fen Bilimleri Enstitüsü Doktora Tezi, Ankara.
2. Zorlugenç FK. 2010. Ozmotik dehidrasyon uygulamasının Trabzon hurması meyvelerinin kuruma davranıflı ve ürün kalitesi üzerine etkileri. Çukurova Üniversitesi Fen Bilimleri Enstitüsü, Gıda Mühendisli¤i Anabilim Dalı Doktora Tezi, Adana.
3. Karakasova L, Babanovska-Milenkovska F, Lazov M, Karakasov B, Stojanova M. 2013. Quality properties of solar dried persimmon (diospyros kaki). J Hygienic Eng Des. 4: 54-59.
4. Yönel S, Uylaser V, Yonak S. 2008. Trabzon hurmasının bileflimi ve besleyici de¤eri, Türkiye 10. Gıda Kongresi, Erzurum, Türkiye, 339-342.
5. Bölek S, Obuz E. 2014. Quality characteristics of Trabzon persimmon dried at several temperatures and pretreated by different methods. Turk J Agric For. 38: 1-8.
6. Park YS, Jung ST, Kang SG, Licond ED, Ayala ALM, Tapia MS, Belloso OM, Trakhtenberg S, Gorinstei S. 2006. Drying of persimmons (Diospyros kaki L.) and the following changes in the studied bioactive compounds and the total radical scavenging activities. LWT- Food Sci Technol. 39: 748-755.
7. Doymaz I. 2012. Evaluation of some thin-layer drying models of persimmon slices (Diospyros kaki L.). Energ Convers Manage. 56: 199-205.
8. Doymaz I. 2007. The kinetics of forced convective air-drying of pumpkin slices. J Food Eng. 79: 243-248.

9. Saeed IE. 2010. Solar Drying of Roselle (Hibiscus sabdariffaL.) part I: Mathematical modelling, drying experiments, effects of the drying conditions. Agric Eng Int: CIGR J. 12 (3-4): 54-59.
10. Crank, J. 1975. The Mathematics of Diffusion. Oxford University Press, London.
11. Incropera FP, De Witt DP. 1990. Fundamentals of Heat and Mass Transfer. John Wiley&Sons, New York
12. Gould AW. 1977. Food Quality Assurence. The AVI Publishing Company Inc. USA.
13. Kaya A, Aydın O, Demirtas C, Akgün M. 2007. An experimental study on the drying kinetics of quince. Desalination 212: 328-243.
14. Kaya A, Aydın O, Demirtas C. 2007. Drying kinetics of red delicious apple. Biosyst Eng. 96(4): 517-524.
15. Doymaz I. 2007. Air-drying characteristics of tomatoes. J Food Eng. 78: 1291-1297.
16. Ahmed J, Shivhare US. 2001. Effect of pre-treatment on drying characteristics and colour of dehydrated green chillis. J Food Sci Technol. 38: 504-506.
17. Akpinar EK, Bicer Y. 2004. Modelling of the drying of eggplants in thin-layers. Int J Food Sci Techol. 39: 1-9.
18. Lewis WK. 1921. The rate of drying of solid materials. J Indian Eng Chem. 13(5): 427-432.
19. Henderson SM, Pabis S. 1961. Grain drying theory. II. Temperature effects on drying coefficients. J Agr Eng Res. 6: 169-174.
20. Sharaf-Eldeen YI, Blaisdell JL, Hamdy MY. 1980. A model for ear corn drying. Trans ASAE 23: 1261-1271.