Experimental Investigation of Drying Kinetics of Trabzon Persimmon (Diospyros kaki L.)

Abstract

This 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

Trabzon Hurmasının (Diospyros kaki L.) Kuruma Davranışının Deneysel İncelenmesi

Abstract

Bu çalıflmada, Kahramanmarafl’ta yetiflen Trabzon hurmasının kuruma davranıflı deneysel olarakincelenmifltir. Deneyler üç farklı hız (0.5, 1.0 ve 1.5 m/s) ve üç farklı sıcaklıkta (40, 50 ve 60 °C)konvektif bir kurutucuda yapılmıfltır. Elde edilen kuruma e¤rileri, literatürde kullanılan üç farklı incetabakalı kurutma modeline yerlefltirilmifltir (Lewis, Henderson-Pabis ve iki terimli eksponansiyel).Hurmanın kuruma karakteristi¤ini tanımlamada iki-terimli eksponansiyel ve Henderson-Pabis modellerininuygun oldu¤u belirlenmifltir. Difüzyon Deffve kütle taflınım hmkatsayılarının kurutma havası sıcaklı¤ıylade¤iflimleri belirlenmifl ve artan sıcaklıkla bu katsayılarında arttı¤ı tespit edilmifltir. Ayrıca kurutma havasısıcaklı¤ının hurmanın renk de¤iflimi, su aktivitesi ve protein de¤iflimine olan etkisi de belirlenmifltir

Keywords

• Trabzon hurması
• kuruma kineti¤i
• kurutma modelleri
• difüzyon katsayısı
• kütletaflınım katsayısı
• renk analizi

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