Thin Layer Drying Process of Some Leafy Vegetables under Open Sun

2007 ◽  
Vol 13 (1) ◽  
pp. 35-40 ◽  
Author(s):  
O. P. Sobukola ◽  
O. U. Dairo ◽  
L. O. Sanni ◽  
A. V. Odunewu ◽  
B. O. Fafiolu
Keyword(s):  
Thin Layer ◽  
Effective Diffusivity ◽  
Thin Layers ◽  
Leafy Vegetables ◽  
Drying Process ◽  
Chi Square ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Drying Models ◽  
Drying Curves

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.

scholarly journals Drying of green bean and okra under solar energy

2011 ◽  
Vol 17 (2) ◽  
pp. 199-205 ◽  
Author(s):  
İbrahim Doymaz
Keyword(s):  
Green Bean ◽  
Chi Square ◽  
Sun Drying ◽  
Constant Rate ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Drying Models ◽  
Drying Curves ◽  
The Times

In this study, sun drying behaviours of green bean and okra were investigated. Drying experiments were conducted in Iskenderun-Hatay, Turkey. The drying study showed that the times taken for drying of green bean and okra from the initial moisture contents of 89.5% and 88.7% (w.b.) to final moisture content of around 15?0.5% (w.b.) were 60 and 100 h in open sun drying, respectively. The constant rate period is absent in drying curves. The drying process took place in the falling rate period. The drying data were fitted to thirteen thin-layer drying models. The performance of these models was investigated by comparing the determination of coefficient (R2), reduced chi-square (c2) and root mean square error (RMSE) between the observed and predicted moisture ratios. Estimations by Approximation of diffusion (for green bean) and Midilli et al. models (for okra) were in good agreement with the experimental data obtained.

scholarly journals Some Aspects of the Modelling of Thin-Layer Drying of Sawdust

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 726
Author(s):  
Andrzej Bryś ◽  
Agnieszka Kaleta ◽  
Krzysztof Górnicki ◽  
Szymon Głowacki ◽  
Weronika Tulej ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Thin Layer ◽  
Air Temperature ◽  
Mean Square ◽  
Drying Process ◽  
Airflow Velocity ◽  
Chi Square ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Drying Models

Drying of spruce, beech, willow, and alder sawdust was examined in a laboratory type dryer. The effect of drying air temperature T (25, 60, and 80 °C) and airflow velocity v (0.01, 0.15, and 1.5 m/s) was investigated. The obtained results demonstrated that drying air temperature and airflow velocity have impacts on the drying of sawdust. The experimental dehydration data of sawdust obtained were fitted to theoretical, semi-theoretical, and empirical thin-layer models. The accuracies of the models were estimated using the correlation coefficient (R), root mean square error (RMSE), and reduced chi-square (χ2). All models except the theoretical model of a sphere described the drying characteristics of sawdust satisfactorily. The effect of T and v on the parameters (constants and coefficients) of the drying models were determined. The effect, by the proposed equations, was also described. This work combines aspects of mechanical engineering and modelling of the drying process.

scholarly journals Thin layer drying of zucchini in solar dryer located in Osmaniye region

2018 ◽  
Vol 12 (2) ◽  
pp. 79-85 ◽  
Author(s):  
Kamil Neyfel Çerçi ◽  
Özge Sufer
Keyword(s):  
Thin Layer ◽  
Linear Regression Analysis ◽  
Chi Square ◽  
Mathematical Expressions ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Drying System ◽  
Thin Layer Drying Models ◽  
Dehydration Behavior ◽  
And Diffusion

In this study, the dehydration behavior of zucchini using solar assisted drying system was examined according to 22 thin layer drying models available in literature. The correlation coefficient (R2), chi-square (χ2) and root mean square error (RMSE) values were calculated to check the suitability of models by non-linear regression analysis. It was found that Cubic and Modified Midilli-1 models were the most suitable equations and their R2 values were calculated as 0.99963. χ2 and RMSE values of related mathematical expressions were 1.89343×10‒5, 1.91692×10‒5 and 0.01685×10‒3, 0.01721×10‒3 respectively. In addition, heat transfer, mass transfer and diffusion coefficients, which were important parameters in design of drying systems were also determined as 5.18124 W/m2°C, 1.57129×10‒7 m/s and 2.335718×10‒9 m2/s respectively.

scholarly journals Thin Layer Drying Kinetics Modelling of Curry Leaves (Murraya koenigii L.) in Cabinet Dryer

2018 ◽  
Vol 2 ◽  
pp. 53-58
Author(s):  
Arjun Ghimire ◽  
Nirajan Magar
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Effective Diffusivity ◽  
Coefficient Of Determination ◽  
Murraya Koenigii ◽  
Small Tree ◽  
Chi Square ◽  
Kinetics Modelling ◽  
Curry Leaves ◽  
Thin Layer Drying

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.

Drying Process Modelling for Heavy Clay Products Using a New Thin Layer Drying Model

2013 ◽  
Vol 371 ◽  
pp. 323-327
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević
Keyword(s):  
Thin Layer ◽  
Mathematical Models ◽  
Process Modelling ◽  
Experimental Investigations ◽  
Drying Process ◽  
Thin Layer Drying ◽  
Heavy Clay ◽  
Drying Models ◽  
Drying Model ◽  
Thin Layer Drying Models

Drying results, determined on samples made of masonry clay from the locality "Banatski Karlovac", are presented in this study. Experimental investigations were carried out in a laboratory recirculation dryer in which drying parameters (humidity, temperature, and velocity) could be programmed, controlled and monitored during drying process. Several mathematical models were used for drying process modelling. New semi-theoretical thin layer drying model, for heavy clay products, was developed and presented in this study. It represents a modification of Page's and logarithm's thin layer drying models. Results presented in this study have shown that new thin layer drying model describes and correlates the best experimentally determined drying process.

scholarly journals Drying Kinetics of Sliced Pineapples in a Solar Conduction Dryer

2017 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Luqman Ebow Ibn Daud ◽  
Isaac Nyambe Simate
Keyword(s):  
Thin Layer ◽  
Average Moisture Content ◽  
Drying Time ◽  
Sun Drying ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Drying Model ◽  
Thin Layer Drying Models ◽  
Drying Curves ◽  
Kinetics Of

As a means of adding value to pineapple production and minimising post-harvest losses, sliced pineapples were dried using a Solar Conduction Dryer (SCD) and appropriate thin layer drying models to predict drying were developed whilst the performance of the SCD was also investigated. For the period of the experiment, ambient temperature and temperature in the dryer ranged from 24 to 37 °C and 25 to 46 ℃ respectively. The performance of the dryer was compared to open sun drying using pineapple slices of 3-5 mm in thickness where the slices were reduced from an average moisture content of 85.42 % (w.b.) to 12.23 % (w.b.) by the SCD and to 51.51 % (w.b.) by the open sun drying in 8 hours effective drying time. Pineapple slices of thicknesses 3 mm, 5 mm, 7 mm and 10 mm were simultaneously dried in the four drying chambers of the SCD and their drying curves simulated with twelve thin layer drying models. The Middilli model was found as the best fitted thin layer drying model for sliced pineapples. The optimum fraction of drying tray area that should be loaded with pineapples was also investigated by simultaneously loading 7 mm slices of pineapples at 50, 75, and 100 percent of drying tray area. Loading the slices at 50, 75 and 100 percent of drying tray area gave overall thermal efficiencies of 23, 32 and 44 percent, respectively, hence loading pineapple slices at 100 percent drying tray area was recommended as the best.

scholarly journals Modelling and characteristics of thin layer convective air-drying of thyme (Thymus vulgaris) leaves

2019 ◽  
Vol 37 (No. 2) ◽  
pp. 128-134
Author(s):  
Osman Yağız Turan ◽  
Ebru Fıratlıgil
Keyword(s):  
Thin Layer ◽  
Goodness Of Fit ◽  
Food Preservation ◽  
Moisture Ratio ◽  
Coefficient Of Determination ◽  
Thymus Vulgaris ◽  
Drying Process ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Kinetics Of

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.

scholarly journals Thin layer drying behaviour of fermented cocoa (Theobroma cacao L.) beans

2018 ◽  
Author(s):  
Saheeda Mujaffar ◽  
Aveena Ramroop ◽  
Darin Sukha
Keyword(s):  
Thin Layer ◽  
Rest Period ◽  
Effective Diffusivity ◽  
Constant Diffusion Coefficient ◽  
Constant Diffusion ◽  
Thin Layer Drying ◽  
Drying Behavior ◽  
Drying Behaviour ◽  
Drying Curves ◽  
The Impact

To assess the impact of a rest interval and bean turning on the thin-layer drying behavior of fermented cocoa beans, beans of mixed Trinitario varieties were dried in a cabinet oven at three temperatures (40, 50, 60°C) using three drying regimes, namely; continuous drying, intermittent drying (drying for 8h with a rest period of 16h), and intermittent drying with turning of beans.  Moisture content, water activity, pH and colour attributes were measured and sensory evaluation of the cocoa liquor carried out on selected samples.  Drying curves were constructed and drying rate constants (k) and effective diffusivity (Deff) values determined. Keywords: Oven-drying; Fick’s Law; Rate constant; Diffusion coefficient

scholarly journals Dehydration Kinetics of Cassava, Yam and Potato Slices Using a Refractance WindowTM Dryer

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Akinjide A Akinola ◽  
Stanley N. Ezeorah
Keyword(s):  
Moisture Content ◽  
Thin Layer ◽  
Coefficient Of Determination ◽  
Plastic Film ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Thin Layer Drying Models ◽  
Drying Curves ◽  
Kinetics Of ◽  
Potato Slices

 This study aims to investigate the drying characteristics of cassava, yam, and potato slices using a laboratory scale batch Refractance Window™ (RW) dryer. The experimental dryer was constructed by modifying a laboratory water bath. The bath was covered with a transparent Polyethylene terephthalate (PET) plastic film held in-place with angled edges. The cassava, yam, and potato slices were dried on the Refractance WindowTM dryer, and the variation of the moisture content of the slices during the drying process was measured. The water temperature beneath the plastic film was maintained at 60oC. The dehydration data were fitted to thin-layer drying models. Regression analysis suggested that the Haghi and Ghanadzadeh model best describes the dehydration behaviour for the 3 mm thick slices for the cassava, yam, and potato tubers. The coefficient of determination (R2) values of 0.999, 0.998, and 0.998 for the cassava, yam, and potato slices respectively were reported in all the models studied. The drying curves, the drying rate curves, and the Krischer curves, from the experimental drying data, was plotted. Observations indicate that the cassava, yams, and potatoes slices dried to below 0.11 g water/g-solid moisture content in about 150 min. This study was performed to facilitate the understanding of the design, modelling, and operations of a continuously operating RW dryer. Keywords: Refractance Window Drying, Thin Layer Drying Models, Yams, Cassava, Potatoes.

Modeling of Thin Layer Drying of Banana (Nendran Spp) under Microwave, Convective and Combined Microwave-Convective Processes

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Magesh Ganesapillai ◽  
I. Regupathi ◽  
Thanapalan Murugesan
Keyword(s):  
Thin Layer ◽  
Microwave Drying ◽  
Convective Drying ◽  
Mean Bias Error ◽  
Bias Error ◽  
Slice Thickness ◽  
Drying Process ◽  
Chi Square ◽  
Drying Time ◽  
Thin Layer Drying

Drying kinetics of microwave, convective and microwave assisted convective drying of thin layer Nendran banana was investigated on a modified microwave oven. The drying characteristics through the operating parameters of the drying process, such as power output, air temperature, slice thickness and sample mass in terms of drying rate equation, were analyzed. An appropriate empirical model to represent the drying process was established by analyzing the available literature models with current experimental data. The statistical analysis for the selected model was performed, parameters like Mean Bias Error, Root Mean Square Error, reduced chi square and t-stat were estimated to examine the consistency of the model to represent the present experimental results. Higher rates and shorter drying times were achieved at a higher temperature and microwave heating power and lesser sample thickness and load. Microwave drying resulted in a substantial decrease in the drying time with better quality product when dried at higher power (300 W) level compared to other processes.

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