scholarly journals Estimating the Drying Kinetics and Effective Moisture Diffusivity of Fresh Water Prawn (Macrobrachium rosenbergii)

Author(s):  
Egbe E. W. ◽  
Davies R. M.

Fresh-water prawn (Macrobrachium rosenbergii) once harvested, tends to deteriorate rapidly because of the high systemic moisture it constituent which has lead to post-harvest losses, drying as a method of preservation widely used for high moisture bio-products reduces moisture probably to bone-dry level and thereby increased the shelf-life of the fresh-water prawn. Therefore, Estimating the Drying Kinetics and Effective Moisture Diffusivity of Fresh Water Prawn (Macrobrachium rosenbergii) was investigated using a laboratory convective oven dryer and was arranged in a thin layer. 50-100°C temperatures were applied, varying on multiple of 10°C. It was observed that the drying rate increased with increasing drying temperatures. Drying data obtained were fitted into four empirical thin-layer drying models, and the best model was investigated after undergoing statistical parameters (of coefficient of determination, R2; root mean square error, RMSE and reduced chi-square, χ2). The ANN and Henderson model was found to perform satisfactorily in describing the drying behaviour of the Fresh-water prawn samples at the chosen temperature levels. The initial moisture content of all the samples was 54% wb. The final effective moisture diffusivity of the samples during the drying experiments ranges from 1.26 x 10-7m2/s - 7.06 x 10-7m2/s, and the temperature related activation energy of diffusion was found to be 12.82-kJ/mol. Drying occurred mainly in the falling rate period, and the characterizing drying curves were exponential with increase in drying temperatures.

2021 ◽  
Vol 8 (2) ◽  
pp. 53-62
Author(s):  
Hendri Syah ◽  
Armansyah Halomoan Tambunan ◽  
Edy Hartulistiyoso ◽  
Lamhot Parulian Manalu

The objectives of this study were to determine a suitable thin layer drying model to describe the drying kinetics of Guazuma ulmifolia leaves and determine the mass transfer parameters of Guazuma ulmifolia leaves. The drying of Guazuma ulmifolia leaves was conducted in a laboratory scale dryer with various temperature (40oC, 50oC, and 60oC) and relative humidity (30%, 40%, 50% and 60%). Five drying models, namely, Newton, Henderson and Pabis, Page, Midilli-Kucuk, and Verma et al. were fitted to the drying data. The drying curve of guazuma leaves did not show a constant drying period during the drying period. The models suitability were compared base on coefficient of determination (R2), root square mean errors (RSME), and reduced mean square of deviation (X2). It was found that, among the models evaluated, the Midilli and Kucuk model is the best to describe the drying kinetics of Guazuma ulmifolia leaves. The effective moisture diffusivity was found to be in the range of 10-13 – 10-12 m2/s and the convective mass transfer coefficient was in the range of 10-9 – 10-10 m/s. The activation energy value was found to be 89.21 kJ/mol.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lahcen Hssaini ◽  
Rachida Ouaabou ◽  
Hafida Hanine ◽  
Rachid Razouk ◽  
Ali Idlimam

AbstractFirst convectional thin layer drying of two fig (Ficus carica L.) varieties growing in Moroccan, using partially indirect convective dryer, was performed. The experimental design combined three air temperatures levels (60, 70 and 80 °C) and two air-flow rates (150 and 300 m3/h). Fig drying curve was defined as a third-order polynomial equation linking the sample moisture content to the effective moisture diffusivity. The average activation energy was ranged between 4699.41 and 7502.37 kJ/kg. It raised proportionally with the air flow velocity, and the same pattern were observed for effective moisture diffusivity regarding drying time and velocity. High levels of temperature (80 °C) and velocity (300 m3/h) lead to shorten drying time (200 min) and improve the slices physical quality. Among the nine tested models, Modified Handerson and Pabis exhibited the highest correlation coefficient value with the lowest chi-square for both varieties, and then give the best prediction performance. Energetic investigation of the dryer prototype showed that the total use of energy alongside with the specific energy utilization (13.12 and 44.55 MWh/kg) were inversely proportional to the velocity and drying temperature. Likewise, the energy efficiency was greater (3.98%) higher in drying conditions.


2016 ◽  
Vol 369 ◽  
pp. 119-124
Author(s):  
E.M.A. Pereira ◽  
J.V. Silva ◽  
J.P.S. Santos ◽  
T.H.F. Andrade ◽  
A.G. Barbosa de Lima

This work aims to conduct an experimental study of the drying kinetics of castor bean fruits (Ricinuscommunis L., “BRS Energia” variety). Experiments were conducted using an oven at air temperatures 50 and 70°C and air relative humidity values 16.34 and 6.24%, respectively. The castor bean fruits were considered as a triaxial spheroid. The experimental moisture content data as a function of time were fitted to different lumped models (namely Henderson and Pabis, Page, Midilli and two-term exponential models) available in the literature.The values of the effective moisture diffusivity were obtained from the Fick's diffusion model. Results shows that the two-term drying model could adequately describe the thin layer drying behavior of castor bean fruit, and that the effective moisture diffusivity increases with increasing drying air temperature.


2016 ◽  
Vol 22 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Monika Lutovska ◽  
Vangelce Mitrevski ◽  
Ivan Pavkov ◽  
Vladimir Mijakovski ◽  
Milivoj Radojcin

In this study, a thin - layer drying of pear slices as a function of drying conditions were examined. The experimental data set of thin - layer drying kinetics at five drying air temperatures 30, 40, 50, 60 and 70?C, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate industrial convective dryer. Five well known thin - layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, numerical experiments were made. For each model and data set, the statistical performance index, (?), and chi-squared, (?2), value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Midilli gives the best statistical results. Because the effect of drying air temperature and drying air velocity on the empirical parameters was not included in the base Midilli model, in this study the generalized form of this model was developed. With this model, the drying kinetic data of pear slices can be approximated with high accuracy. The effective moisture diffusivity was determined by using Fick?s second laws. The obtained values of the effective moisture diffusivity, (Deff), during drying ranged between 6.49 x 10-9 and 3.29 x 10-8 m2 s-1, while the values of activation energy (E0) varied between 28.15 to 30.51 kJ mol-1.


2013 ◽  
Vol 8 (2) ◽  
pp. 107-117 ◽  
Author(s):  
Hosain Darvishi ◽  
Gholamhassan Najafi ◽  
Adel Hosainpour ◽  
Jala Khodaei ◽  
Mohsen Aazdbakht

Abstract In this study, infrared drying characteristic of mushroom slices was investigated in the temperature range of 50–90°C. The drying data were fitted to five thin-layer drying models. The performance of these models was compared using the determination of coefficient (R2), reduced chi-square (χ2), and root mean square error between the observed and predicted moisture ratios. The values of the diffusivity coefficients at each temperature were obtained using Fick’s second law of diffusion. The drying processes were completed within 60–168 min at different temperatures. Experimental drying curves showed only a falling drying rate period. The results show that the logarithmic model is the most appropriate model for infrared drying behavior of thin-layer mushroom slices. A third-order polynomial relationship was found to correlate the effective moisture diffusivity with moisture content. The average effective moisture diffusivity increased with increasing temperature and decrease in moisture content of mushroom slices and varied from 8.039 × 10−10 to 20.618 × 10−10 m2/s. Arrhenius relation with an activation energy value of 21.85 kJ/mol expressed the effect of temperature on the average diffusivity. The minimum and the maximum energy requirements for drying of mushroom slices were also determined as 2.87 kW h/kg water and 5.36 kW h/kg water for 90 and 50°C, respectively.


2018 ◽  
Vol 6 (2) ◽  
pp. 552-565 ◽  
Author(s):  
Eunice Akello Mewa ◽  
Michael Wandayi Okoth ◽  
Catherine Nkirote Kunyanga ◽  
Musa Njue Rugiri

The objective of the present study was to determine the drying kinetics, moisture diffusivity and sensory quality of convective air dried beef. The effect of temperature of drying (30-60°C) and thickness of samples (2.5-10 mm) on the convective thin-layer drying kinetics of beefdried in a cabinet dryer was evaluated. Five semi-theoretical models were fit to the drying experimentaldata with the aim of predicting drying characteristics of beef and fitting quality of models determined using the standard error of estimate (SEE)and coefficient of determination (R2). Determination ofeffective moisture diffusivity (Deff) from the experimental drying datawas done and sensory quality of the optimized dried cooked and uncookedbeef samplesevaluated. Drying time and rate of drying increased with an increasing temperature but decreased with increased slice thickness. However, there was overlapping of drying curves at 40-50°C. Among the selected models, Page model gave the best prediction of beef drying characteristics. Effective moisture diffusivity (Deff) ranged between 4.2337 x 10-11 and 5.5899 x 10-10 m2/s, increasing with an increase in air temperature and beef slice thickness.Of all the sensory parameters evaluated, texture was the only attribute that gave significantly different (P > 0.05) scores between the cooked and uncooked dried beef samples.


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