Freeze Drying Kinetics of Persimmon Puree

Year 2015, Volume: 40 Issue: 1, 15 - 21, 01.03.2015

Gülşah Çalışkan, S. Nur Dirim

Abstract

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

Keywords

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

Cennet Elması Püresinin Dondurarak Kurutma Kinetiğinin Belirlenmesi

Abstract

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

Keywords

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

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