Modeling of Thin-Layer Drying of Apple Slices in a Semi-Industrial Continuous Band Dryer

Author(s):  
Mortaza Aghbashlo ◽  
Mohammad Hossien Kianmehr ◽  
Akbar Arabhosseini

The drying kinetics of apple slices was investigated in a semi-industrial continuous band dryer. Apple slices with a thickness of 5 mm were dried at temperatures of 50, 60 and 70 °C, air velocities of 0.5, 1.0 and 1.5 m/s and chain linear velocity of 1.85E-04, 2.22E-04 and 2.78E-04 m/s. The Weibull model was fitted to the experimental data of moisture ratio against sample position using MATLAB computer program. The low reduced chi-square and RMSE and the high regression coefficients indicated the suitability of the Weibull model for predicting moisture ratio of apple slices during drying in length of continuous band dryer. Correlations of the scale and shape parameter of the Weibull model with the variables of T, Ua and Uc were determined. The transport of water during drying was described by Fick’s second low and effective diffusivity varied from 9.24E-08 to 3.5E-07 m2/s. The energy of activation was described by the Arrhenius equation and varied from 35.37 to 45.51 kJ/mol.

2011 ◽  
Vol 29 (No. 5) ◽  
pp. 528-538 ◽  
Author(s):  
M. Aghbashlo ◽  
M.H. Kianmehr ◽  
A. Arabhosseini ◽  
T. Nazghelichi

This paper presents a mathematical modelling of the drying process in a semi-industrial continuous band dryer. Carrot slices with the thickness of 5 mm were used for the drying experiments. The experiments were conducted at three air temperatures, 50, 60, and 70&deg;C, three air velocities, 0.5, 1.0, and 1.5 m/s, and three chain linear velocities, 2.38 &times; 10<sup>&ndash;4</sup>, 2.78 &times; 10<sup>&ndash;4</sup>, and 3.33 &times; 10<sup>&ndash;4</sup> m/s with three replications for each treatment. The Lewis, Henderson &amp; Pabis, and Page models were fitted to the experimental data of the moisture ratio against the sample position using non-linear regression analysis by MATLAB computer program. The models were compared based on their coefficients of determination (R<sup>2</sup>), root mean square errors (RMSE), and reduced chi-squares (&chi;<sup>2</sup>) between the experimental and predicted moisture ratios. Consequently, the Page model was selected as the best mathematical model for describing the drying kinetics of the carrot slices. The correlations of the Page model constants k and m with the variables T, U<sub>a</sub> and U<sub>c</sub> were determined. The effective moisture diffusivity varied from 3.21 &times; 10<sup>&ndash;7</sup> to 8.98 &times; 10<sup>&ndash;7 </sup>m<sup>2</sup>/s. The energy of activation varied from 23.02 kJ/mol to 28.1 kJ/mol using Arrhenius type equation. &nbsp;


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vali Rasooli Sharabiani ◽  
Mohammad Kaveh ◽  
Roozbeh Abdi ◽  
Mariusz Szymanek ◽  
Wojciech Tanaś

AbstractTwo different drying methods were applied for dehydration of apple, i.e., convective drying (CD) and microwave drying (MD). The process of convective drying through divergent temperatures; 50, 60 and 70 °C at 1.0 m/s air velocity and three different levels of microwave power (90, 180, and 360 W) were studied. In the analysis of the performance of our approach on moisture ratio (MR) of apple slices, artificial neural networks (ANNs) was used to provide with a background for further discussion and evaluation. In order to evaluate the models mentioned in the literature, the Midilli et al. model was proper for dehydrating of apple slices in both MD and CD. The MD drying technology enhanced the drying rate when compared with CD drying significantly. Effective diffusivity (Deff) of moisture in CD drying (1.95 × 10−7–4.09 × 10−7 m2/s) was found to be lower than that observed in MD (2.94 × 10−7–8.21 × 10−7 m2/s). The activation energy (Ea) values of CD drying and MD drying were 122.28–125 kJ/mol and 14.01–15.03 W/g respectively. The MD had the lowest specific energy consumption (SEC) as compared to CD drying methods. According to ANN results, the best R2 values for prediction of MR in CD and MD were 0.9993 and 0.9991, respectively.


2007 ◽  
Vol 13 (1) ◽  
pp. 35-40 ◽  
Author(s):  
O. P. Sobukola ◽  
O. U. Dairo ◽  
L. O. Sanni ◽  
A. V. Odunewu ◽  
B. O. Fafiolu

Open sun drying experiments in thin layers of crain-crain (CC), fever (FV) and bitter (BT) leaves grown in Abeokuta, Nigeria were conducted. The drying process took place in the falling rate period and no constant rate period was observed from the drying curves. Eight thin layer mathematical drying models were compared using the multiple determination coefficients (R2), reduced chi-square (χ2) and root mean square error (RMSE) between the observed and predicted moisture ratios. Accordingly, Midilli et al. model satisfactorily described the drying curves of the three leaves with R2 of 0.9980, χ2 of 2.0×10-4 and RMSE of 1.09×10-2 for CC leaves; R2 of 0.9999, χ2 of 2×10-6 and RMSE of 1.11×10-3 for FV leaves; and R2 of 0.9998, χ2 of 1.9×10-5 and RMSE of 3.3×10-3 for BT leaves. The effective diffusivity was found to be 52.91×10-10, 48.72×10-10 and 43.42×10-10 m2/s for CC, BT and FV leaves, respectively.


2018 ◽  
Vol 2 ◽  
pp. 53-58
Author(s):  
Arjun Ghimire ◽  
Nirajan Magar

Curry leaves (Murraya koenigii L.) are the sweet smelling leaves of small tree of Rutaceae family native to Southwest Asia. In this study, the effect of temperatures (50, 55 and 60°C) on the drying of curry leaves was investigated. The experimental data were fitted to six thin layer mathematical models (Newton, Page, Handerson and Pabis, logarithmic, two-term exponential and Midilli et al). The models were evaluated in terms of coefficient of determination (R2), chi square (χ2) and root mean square error (RMSE). The Midilli et al model was best fitted to the experimental data of all the models evaluated. The effective diffusivity was calculated using Fick's diffusion equation, and the value varied from 2.07×10-12 m2/s to 2.643×10-12 m2/s. The activation energy and the diffusivity constant were found to be 21.808 kJ/mol and 4.667×10-8 m2/s respectively.


Author(s):  
Sajeev Rattan Sharma ◽  
Sadhna Arora ◽  
Tarsem Chand

The thin layer drying of pretreated wild pomegranate seeds was conducted in a laboratory mechanical dryer at air temperatures of 55, 60 and 65°C. Six different mathematical models were used to predict the drying behavior. Thompson model was adjudged as the best model. The coefficients of this model were found to be correlated best with drying temperatures by using two degree polynomials. The effective diffusivity was determined to be 3.18 x 10-10 to 4.36 x 10-10 m2/s. The activation energy for diffusion was found to be 29.07 kJ /mol. The variation in shrinkage exhibited a linear relationship with moisture content. The rate constants for “a” and “b” parameters of colour were determined and their value was 0.0128 and 0.0136 min-1, respectively.


2019 ◽  
Vol 37 (No. 2) ◽  
pp. 128-134
Author(s):  
Osman Yağız Turan ◽  
Ebru Fıratlıgil

Fruit and vegetable dehydration has been extensively studied for the improvement of food preservation. Effects of drying temperature on the drying kinetics of thyme were investigated and a suitable drying model was obtained to describe the drying process. Drying behaviour of thyme leaves at temperatures of 50, 60, 70 and 80°C was determined by using a conventional drying oven, and moisture ratio and drying rates were calculated. Four different thin layer drying models, namely Lewis, Henderson and Pabis, Page, and logarithmic models, were used to fit the experimental moisture ratio data. Three statistical parameters: coefficient of determination (R<sup>2</sup>), chi-square (χ<sup>2</sup>) and root mean square error (RMSE) were used to compare the goodness of fit of the drying models. Logarithmic model and Page model give the best description of the drying process kinetics of thyme leaves by comparing the experimental values and predicted values.


Author(s):  
A. A. Satimehin ◽  
M. O. Oluwamukomi ◽  
V. N. Enujiugha ◽  
M. Bello

This study was conducted to determine the drying characteristics of oyster mushroom (Pleurotus ostreatus) at 50, 60 and 70 °C.  Pleurotus ostreatus were cleaned and dried in a laboratory cabinet dryer. The drying data were fitted to six model equations namely Newton, Pabis and Henderson, Logarithmic, Two-term diffusion, Wang and Singh, as well as Modified Henderson and Pabis equations. The goodness of fit of the models were evaluated by means of the coefficient of determination (R2), root mean square error (RMSE) and reduced chi-square (χ2). The Logarithmic model best describes the drying data and could be used to predict its drying behaviour. Keywords: oyster mushroom; thin-layer drying; characteristics; modelling


2021 ◽  
Author(s):  
Vali Rasooli Sharabiani ◽  
Abdi Roozbeh ◽  
Mohammad Kaveh ◽  
Mariusz Szymanek ◽  
Wojciech Tanaś

Abstract Two different drying methods were applied for dehydration of apple, i.e., convection drying (CD) and microwave drying (MD). The process of convection drying through divergent temperatures; 50, 60 and 70°C at 1.0 m/s air velocity and three different levels of microwave power (90, 180, and 360 W) were studied. In the analysis of the performance of our approach on moisture ratio of apple slices, artificial neural networks (ANNs) was used to provide with a background for further discussion and evaluation. In order to evaluate the models mentioned in the literature, the Midilli et al. model was proper for dehydrating of apple slices in both MD and CD. The microwave drying technology enhanced the drying rate when compared with convective drying significantly. Effective diffusivity of moisture in CD drying (1.95×10−7 - 4.09×10−7 m2/s) was found to be lower than that observed in MD (2.94×10−7–8.21×10−7 m2/s). The Ea values of convective drying and microwave drying were 122.28- 125 kJ/mol and 14.01- 15.03 W/g respectively. The MD had the lowest SEC as compared to CD drying methods. According to ANN results, the best values for predication of MR in CD and MD were 0.9993 and 0.9990, respectively.


Author(s):  
Raj Kumar Goyal ◽  
Mujjeb O ◽  
Vinod Kumar Bhargava

In this study, the drying kinetics of apple (control, blanching and blanching in 1% potassium meta bisulphate) in a tunnel dryer was studied at 50, 60, and 70°C air temperatures. The drying of apple slices occurred in a falling rate period. It was found that treated apple slices dried faster. Six thin layer-drying models were fitted to the experimental moisture ratio. Among the mathematical models evaluated, the logarithmic model satisfactorily described the drying behaviour of apple slices with high r2 values. The effective moisture diffusivity (Deff) of apple slices increased as the drying air temperature increased. The Deff values were higher for the treated samples than for the control.


2019 ◽  
Vol 49 (4) ◽  
pp. 213-218
Author(s):  
Seda Kayran ◽  
Íbrahim Doymaz

Effect of infrared powers (62, 74, 88, 104 and 125 W) on drying kinetics of apricot pomace was investigated. It is observed that drying characteristics of apricot pomace were greatly influenced by infrared power. Henderson and Pabis model was investigated for describing thin-layer drying of apricot pomace. The model because of the high coefficient of determination (R2) as well as the lowest reduced chi-square (c2) and root mean square error (RMSE) values adequately described the experimental data of apple pomace drying. Effective moisture diffusivity (Deff) values were increased by increasing infrared power and changed between 1.67×10-9 and 6.03×10-9 m2/s. Activation energy was estimated by a modified Arrhenius type equation and found to be 2.32 kW/kg. The colour results were affected by drying conditions.


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