scholarly journals Effect of Ethyl Oleate Pretreatment on Drying of Ginger: Characteristics and Mathematical Modelling

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
A. Waheed Deshmukh ◽  
Mahesh N. Varma ◽  
Chang Kyoo Yoo ◽  
Kailas L. Wasewar

Ginger is of high value and export oriented commodity crop, which plays an important role in agricultural sector. Proper drying techniques are required to capitalize this crop. In the present study, the effect of chemical pretreatment of alkaline ethyl oleate on drying behaviour of ginger was investigated and compared with untreated ginger at selected temperatures of 45, 55, and 65°C at a constant air velocity of 1.8 m/s. The drying rate curves showed that drying occurred in falling rate period and the drying times of pretreated ginger were shorter than those of untreated ginger. Thin-layer drying models such as Newton, Page, Modified Page, Henderson and Pabis, and Wang and Singh were evaluated based on statistical criteria. The Page model was found to be a better model for describing the drying kinetics of the ginger. The rehydration capacity of pretreated sample was more than that of untreated sample and increased with drying temperature. The transport of water during drying was temperature dependent and described by Fick’s equation. The effective diffusivity varied from to  m2/s and to  m2/s with drying temperature for untreated and pretreated ginger slices, 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.


2014 ◽  
Vol 16 (4) ◽  
pp. 60-65 ◽  
Author(s):  
F. Sabet Sarvestani ◽  
A. Rahimi ◽  
M.S. Hatamipour

Abstract In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a pilot scale forced convective dryer. Experiments carried out under various operating conditions including air temperature (40, 50, 60, 70°C), air velocity (0.65, 2.1, 3.45, 4.85 m/s) and air humidity (0.005, 0.010, 0.015 kg/kg) and the effects of these operating conditions on the drying kinetics and the drying time determined. The obtained kinetics data are fitted into a conceptually developed model. The equilibrium moisture content of the dried figs is determined at different values of temperature and relative humidity of air. The values of effective moisture diffusivity (Deff) are obtained from the Fick’s second law and a temperature-dependent relation is proposed for this parameter.


2014 ◽  
Vol 60 (No. 3) ◽  
pp. 92-99 ◽  
Author(s):  
V.A. REVASKAR ◽  
P.S. PISALKAR ◽  
P.B. PATHARE ◽  
G.P. SHARMA

The effect of different pre-treatments (i.e. osmotic dehydration in 10, 15 and 20°Brix NaCl solution and drying air temperature of 50, 60 and 70°C) on drying behaviour of onion slices were investigated. The onion slices were dried in a laboratory model tray dryer. Drying of onion slices occurred in falling rate period. Five thin-layer drying models (Exponential, Page, Henderson and Pabis, Logarithmic and Power law) were fitted to the moisture ratio data. Among the drying models investigated, the Page model satisfactorily described the drying behaviour of onion slices. The effective moisture diffusivity of pre-treated samples was higher than that of non-treated samples


2019 ◽  
Vol 25 (3) ◽  
pp. 229-237 ◽  
Author(s):  
de Domingues ◽  
de Gomes ◽  
Marcello Nitz

The major residue from beer production is the brewer?s spent grain (BSG). At present, BSG is mainly used as feed for cattle. Spent grains have been considered as a potential source of protein and energy for human nutrition. For such use, BSG must be dried to reduce its mass and increase its shelf life. In this study, the drying kinetics of BSG were investigated in a tray dryer and in a pulsed fluidized bed (PFB) dryer. Five different combinations of temperature and air velocity (70?C and 1.0 m/s, 70?C and 1.7 m/s, 80?C and 1.35 m/s, 90?C and 1.0 m/s, 90?C and 1.35 m/s) were investigated for the tray dryer and four for the PFB at 900 rpm (70?C and 0.52 m/s, 70?C and 0.72 m/s, 90?C and 0.52 m/s, 90?C and 0.72 m/s). Six thin-layer drying models were fitted to the experimental data obtained for the tray dryer: Lewis, Page, Modified Page, Midilli et al., Verma et al. and Henderson-Pabis. Both temperature and air flow influenced drying rate. A moisture ratio reduction of 90% was four times faster at 90?C and 1.7 m/s than at 70?C and 1.0 m/s in the tray dryer. The drying models, except Lewis, showed good fit. Drying in the PFB was considerably faster compared to the tray dryer. A moisture reduction of 90% was twice as fast at 90?C and 0.72 m/s (PFB) than at 90?C and 1.70 m/s (tray dryer).


Author(s):  
Gholamreza Askari ◽  
Atefe Babaki ◽  
Zahra Emamdjomeh

In order to conserve cuminum cyminum L. during long storage periods, the drying kinetics of this seed undergoing microwave-assisted fluidized bed dryer at various microwave output power (300, 600 and 900w), air velocity (10, 15 and 20 m/s) and air temperatures (45, 55 and 65ᵒc) were studied. The main aim of this research is developing a mathematical model of mass transfer to investigate the microwave-assisted fluidized bed drying of cuminum cyminum L. seed. In this paper, we tried to discover a good model to evaluate moisture effective diffusivity (Deff). Keywords: cuminum cyminum L, microwave-assisted drying, mathematical modeling,


2020 ◽  
Vol 42 ◽  
pp. e40570
Author(s):  
Ibrahim Doymaz

Kiwifruit slices were dried at four different air drying temperatures of 50, 55, 60 and 70ºC and at 2 m s-1 air velocity by using a cabinet dryer in this study. The drying, rehydration and colour characteristics were significantly influenced by pretreatment and drying temperature. The drying time decreased with the increase in drying temperature. The drying rate curves showed that the entire drying process took place in the falling rate period. Five well-known thin-layer models were evaluated for moisture ratios using nonlinear regression analysis. The results of regression analysis indicated that the Midilli & Kucuk model the best to describe the drying behaviour with the lowest c2 and RMSE values, and highest R2 value. The effective moisture diffusivity of the dried kiwifruit slices was calculated with Fick’s diffusion model, in which their values varied from 4.19×10–10 to 6.99×10-10 m2 s-1 over the mentioned temperature range. The dependence of effective diffusivity coefficient on temperature was expressed by an Arrhenius type equation. The calculated values of the activation energy of moisture diffusion were 10.37 and 19.08 kJ mol-1 for citric acid and control samples, 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.


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.


The study is aimed experimentally and compared with the theoretical results of drying kinetics of Nagpur orange fruit dried in a hot air electrical dryer. Orange fruit is highly perishable and needs to be consumed or processed immediately after harvest. Drying or dehydration is one of the most practical methods of preserving food products. Therefore, thin layer drying characteristics of falling rate of Nagpur orange are determined experimentally under different conditions of drying air temperatures, relative humidity and air velocities for different moisture contents. Thin layer models like Wang and Singh, Page and Henderson have been compared with Experimental results. The knowledge of drying kinetics helps for identification of exact drying time and air flow velocity for different moisture content. Here drying operation is carried out at a velocity of 1m/sec and 1.25 m/sec for different temperature of 55°C, 65°C and 75°C. This analysis reveals that drying temperature has a more significant effect on moisture removal while velocity has the least effect. Drying rate is found to increase with the increase in drying temperature and reduce with drying time. Experimental data is statistically correlated by plotting the drying characteristics curve. The analysis reveals that Wang and Singh's model is a better model to explain the drying behavior of Nagpur Orange fruit (R2=0.9888).


2021 ◽  
Vol 13 (1) ◽  
pp. 59-72
Author(s):  
Javid Ghasemi ◽  
Mehdi Moradi ◽  
Sayed Hossein Karparvarfard ◽  
Mohammad Taghi Golmakani ◽  
Amin Mousavi Khaneghah

The thin-layer drying kinetics of lemon verbena leaves were studied by using a solar cabinet dryer at air tempera-ture (at three levels of 30, 40, and 50°C), air velocity (at three levels of 2, 2.5, and 3 m/s), and mesh tray size (3, 6, and 10 mm). A completely randomized factorial design was used to analyze the effect of independent factors on drying time and essential oil yield. Results showed that all experiments have shorter drying time and higher essen-tial oil content than the shade-drying method. Also, the best drying conditions that led to an optimal essential oil yield (1.73 mL/g DM) involved a lower temperature (30°C) and velocity (2 m/s) and a mesh size of 10 mm. A good adaptation between the experimental and the predicted moisture content was observed, whereby the statistical criteria of R2, root mean square error, and k2 were calculated as 0.99, 0.08, and 0.01, respectively. Practical applicationsIn the current study, the effect of different drying states such as air velocity and drying temperature was studied on the drying behaviors and essential oil contents of lemon verbena leaves. The obtained results can lead us to a suitable drying condition that can be used in the subsequent designation of systems. Also, a mathematical model for the pre-diction of the leaves’ drying kinetics was constructed and evaluated, which could be approached in the drying systems.


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