scholarly journals Moisture and thermal diffusivity of lentil seed under convective infrared-microwave: Modelling with and without shrinkage

2016 ◽  
Vol 62 (No. 3) ◽  
pp. 129-140 ◽  
Author(s):  
R.A. Chayjan ◽  
S.A. Radmard
Keyword(s):  
Thermal Diffusivity ◽  
Moisture Content ◽  
Microwave Radiation ◽  
Air Temperature ◽  
Microwave Power ◽  
Infrared Radiation ◽  
Moisture Diffusivity ◽  
Microwave Drying ◽  
Drying Rate ◽  
Mathematical Equations

The effect of infrared radiation and microwave radiation on the moisture and thermal diffusivity characteristics of lentil seeds during infrared and microwave drying was investigated. Using mathematical equations, values and curves, moisture and thermal diffusivity were obtained. This study was to determine the moisture and thermal diffusivity of seed lentil with and without shrinkage at input temperatures 40°C and 60°C, infrared powers 1,000 W and 2,000 W and microwave power 270 W and 450 W, when the moisture content was reduced from 60 to 9% (d.b.). Drying rate was increased with increased air temperature, infrared radiation and microwave powers. Also drying rate decreased continuously with decreasing moisture content. The calculated values of moisture diffusivity by considering shrinkage were smaller than the values of moisture diffusivity without considering shrinkage. Moisture diffusivity with and without shrinkage decreased with decrease in moisture content of lentil seeds and thermal diffusivity with and without shrinkage decreased with increased moisture content. Both moisture and thermal diffusivity values decreased with increase in temperature.

Calculation of Moisture Content and Drying Rate during Microwave Drying

2013 ◽  
Vol 423-426 ◽  
pp. 746-749
Author(s):  
Samad Khani Moghanaki ◽  
Behnam Khoshandam ◽  
Mohammad Hosein Mirhaj
Keyword(s):  
High Temperature ◽  
Moisture Content ◽  
Microwave Power ◽  
Operating Temperature ◽  
Irradiation Time ◽  
Microwave Drying ◽  
Drying Rate ◽  
Microwave Method ◽  
Drying Process ◽  
Drying Time

Convectional dryerswork at high temperature and usually lead to loss of quality for sensitivebiomaterial products (especially in nutrition). In this way the researchersfound the microwave power more effective and suitable for drying processes. Someof microwave drying advantages include the following: short drying time, highquality of product, low operating temperature, flexibility in producing widerange of products and easier process controlling. The article calculated themoisture content and drying rate during drying process. Microwave power, holdertray speed, dimension of samples, irradiation time were considered; under theseconditions experiments were done and the results show that microwave method hasmore advantages as comparing with convectional methods.

scholarly journals Temperature, microwave power and pomace thickness impact on the drying kinetics and quality of carrot pomace

2019 ◽  
Vol 50 (1) ◽  
pp. 28-37
Author(s):  
Ernest Ekow Abano ◽  
Robert Sarpong Amoah ◽  
Eugene Kwabena Opoku
Keyword(s):  
Activation Energy ◽  
Ascorbic Acid ◽  
Air Temperature ◽  
Microwave Power ◽  
Moisture Diffusivity ◽  
Sample Thickness ◽  
Microwave Drying ◽  
Drying Time ◽  
Air Drying

This study investigated the effect of air temperature, microwave power, and pomace thickness on the drying kinetics and quality of dried carrot pomace. The study established that the drying of carrot pomace occurs in the falling rate period, suggesting that drying was driven by molecular diffusion. The microwave-drying moisture diffusivity increased with microwave power and ranged between 1.57×10–8 and 2.61×10–8 m2/s. As regards convective air-drying, the moisture diffusivity values were between 3.38×10–10 and 8.27×10–10 m2/s. The microwave powerto-mass activation energy was 15.079 W/g for 5 mm, 7.599 W/g for 10 mm and 9.542 W/g for 15 mm dried samples. Meanwhile, the temperature-dependent activation energy for carrot pomace was found to be 27.637 kJ/mol for 5 mm, 17.92 kJ/mol for 10 mm and 38.76 kJ/mol for 15 mm thickness pomace. Generally, drying time decreased with increasing microwave power or air temperature. The ascorbic acid content of the fresh carrot pomace reduced after both microwave and convective air-drying. However, microwave power, and sample thickness had significant effect on the β-carotene content of dried products but air temperature did not have a significant effect. The effect of temperature and sample thickness on brown pigment formation was substantial with air temperature compared to microwave. The study has demonstrated that microwave drying, compared to conventional drying, enhances moisture removal, drying time, and preservation of carotenoids and ascorbic acid. Therefore, microwave drying can be considered as an alternative method for obtaining quality dried carrot pomace.

Drying of Rough Rice in Oven: An Experimental Study

2015 ◽  
Vol 365 ◽  
pp. 77-81 ◽  
Author(s):  
J.V. Silva ◽  
E.M.A. Pereira ◽  
T.H.F. Andrade ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Experimental Study ◽  
Relative Humidity ◽  
Moisture Content ◽  
Product Quality ◽  
Air Temperature ◽  
Drying Rate ◽  
Rough Rice ◽  
Drying Conditions ◽  
Kinetics Of ◽  
Mechanical Movement

This paper aims to present an experimental study of rough rice (BRSMG CONAI cultivar) drying by using a stationary method. The grain was dried in an oven with air mechanical movement under controlled conditions of velocity, temperature and relative humidity. In order to obtain balanced moisture content, the samples studied were kept at 40 and 70°C. Results of the drying and heating kinetics of the grain during the process are shown and analyzed. It was found that higher drying rate and lower time for drying as higher air temperature (70°C) is used. It can be concluded that the reduction of the moisture content of the grain, is considered very complex and, depending on the method and drying conditions, can substantially provokes breaking and cracks, which reduces final product quality.

scholarly journals Paddy Drying in Batch Fluidized Bed and Scale-up Simulation in Continuous Operation Mode

2017 ◽  
Vol 2 (6) ◽  
pp. 430 ◽  
Author(s):  
Suherman Suherman ◽  
Mohammad Djaeni ◽  
Dyah Hesti Wardhani ◽  
Andri Cahyo Kumoro
Keyword(s):  
Moisture Content ◽  
Fluidized Bed ◽  
Air Temperature ◽  
Operation Mode ◽  
Scale Up ◽  
Drying Rate ◽  
Two Phase ◽  
Fluidized Bed Dryer ◽  
Fluid Bed ◽  
Experimental Works

The objective of this research is to develop the industrial-scale fluid bed dryer for paddy by scale-up of lab-scale experimental data. The developed dryer was conducted by simulation using a two phase model. Firstly, the experimental works by using lab-scale batch fluid bed dryer, was conducted to determine the drying curve of paddy (Xin 0.32 kg/kg dry base). In the experimental works,the inlet air temperature was varied (°C): 40; 50; 60. The drying rate curves as a function of moisture content showed only decreasing drying rate period. Then, a very good agreement between the measured and simualtion results of the profile of moisture content in solids was produced by simulator. Finally, asimulated continuous fluidized bed dryer for paddy with dimension 5 m of length and 1.5 of width was succesfully performed, in which the influence of mass solid flow rate 0.1; 0.2; 0.4 tons/h, height of bed 0.25; 0.50; 0.75 m, and air temperature 50; 70; 100 °C on drying process were studied. Keywords: Paddy; fluid bed dryer; batch, contonious;  modelling; simulation

scholarly journals Drying characteristics of eggplant (Solanum melongena L.) slices under microwave-convective drying

2016 ◽  
Vol 62 (No. 4) ◽  
pp. 170-178 ◽  
Author(s):  
R.A. Chayjan ◽  
M. Kaveh
Keyword(s):  
Air Temperature ◽  
Microwave Power ◽  
Specific Energy Consumption ◽  
Solanum Melongena ◽  
Moisture Diffusivity ◽  
Moisture Ratio ◽  
Convective Drying ◽  
Air Velocity ◽  
Drying Time ◽  
Thin Layer Drying

A laboratory scale microwave-convection dryer was used to dry the eggplant fruit, applying microwave power in the range of 270–630 W, air temperature in the range of 40–70°C and air velocity in the range of 0.5–1.7 m/s. Six mathematical models were used to predict the moisture ratio of eggplant fruit slices in thin layer drying. The results showed that the Midilli et al. model had supremacy in prediction of turnip slice drying behavior. Minimum and maximum values of effective moisture diffusivity (D<sub>eff</sub>) were 1.52 × 10<sup>–9</sup> and 3.39 × 10<sup>–9</sup> m<sup>2</sup>/s, respectively. Activation energy values of eggplant slices were found between 13.33 and 17.81 kJ/mol for 40°C to 70°C, respectively. The specific energy consumption for drying eggplant slices was calculated at the boundary of 86.47 and 194.37 MJ/kg. Furthermore, in the present study, the application of Artificial Neural Network (ANN) for predicting the drying rate and moisture ratio was investigated. Microwave power, drying air temperature, air velocity and drying time were considered as input parameters for the model.

Convective and microwave drying characteristics, energy requirement and color retention of dehydrated nettle leaves (Urtica diocia L.)

2017 ◽  
Author(s):  
Fuat Lule ◽  
Turhan Koyuncu
Keyword(s):  
Moisture Content ◽  
Air Temperature ◽  
Energy Requirement ◽  
Color Difference ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Color Retention ◽  
Specific Energy Requirement

In this research, convective and microwave drying characteristics, energy requirement and color changes of nettle leaves (Urtica diocia L.) were reported. Samples of freshly harvested nettle leaves were dehydrated under three air temperatures of 50 °C, 60 °C and 70 °C and at three microwave power levels of PL-1, PL-2 and PL-3. Selected drying air velocity was 0.30 m/s for all temperatures. This is coming from the fact that it was understood from the preliminary studies that the temperature less than 50 °C and the air speed more than 0.30 ms-1 increase the drying time and energy requirement, extremely for these products. Nettle leaves were dehydrated from the initial moisture content of 320 (percentage dry basis) to a final moisture content of 7 % to 9 %. During convective drying experiments, product were weighted automatically by the balance per (5 to10) min. Data were transferred to the computer and processed by a software. During microwave drying, the product were weighted and data recorded manually per (15 to 60) min. The influence of drying method, drying air temperature and microwave power level have also been studied. Hunter L, a, b values system was also used to evaluate changes in total color difference (DE) on dried products. The results showed that convective drying air temperature and microwave oven power levels influenced the total drying time, total energy requirement, specific energy requirement and color difference for nettle leaves. The minimum specific energy requirement were determined as 6.95 kWhkg-1 and 23.63 kWhkg-1 for 70 °C and PL-2 respectively. 70 °C drying air temperature and PL-3 was found to yield better quality product in terms of color retention of Hunter L, a, b and DE. As a result, to reduce drying energy consumption and to keep better color retention, convective drying can be recommended for this application.

scholarly journals Effects of sonication and freezing on the color, mechanical and thermophysical properties of osmo-microwave-vacuum dried cranberries

2020 ◽  
Author(s):  
Izabela Anna Staniszewska ◽  
Szymon Staszyński ◽  
Magdalena Zielińska
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Moisture Diffusion ◽  
Moisture Diffusivity ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Volumetric Heat Capacity ◽  
Drying Time ◽  
Microwave Vacuum Drying

The aim of study was to determine the effects of sonication (S), convective freezing (F), convective freezing preceded by sonication (SF) as well as cryogenic freezing (N) on the osmo-microwave-vacuum drying kinetics, energy usage and properties of dried cranberries such as moisture content, moisture diffusion, water activity, density, porosity, thermal conductivity, thermal diffusivity, volumetric heat capacity, lightness, redness, yellowness, total differences in color, saturation and hue, hardness, cohesiveness, springiness, and chewiness. Osmo-microwave-vacuum drying of cranberries took from 13.5 to 16.0 min. All initial treatments increased the moisture diffusivity and thus reduced the drying time. The most energy effective method was osmo-microwave-vacuum drying preceded by sonication (S) of fruits. Osmo-microwave-drying of cranberries subjected to convective freezing preceded by sonication (SF) resulted in the highest lightness (32.5 ± 0.5), redness (33.9 ± 0.7), and yellowness (11.3 ± 0.5) of fruits, as well as the lowest cohesion (the lowest resistant to stress associated with manufacturing, packaging, storage, and delivery). The lowest hardness, i.e. 12.3 ± 0.4 N and the highest cohesiveness and springiness, i.e. 0.38 ± 0.02 and 0.74 ± 0.03 of dried fruits, were noted for berries subjected to initial cryogenic freezing (N). Cryogenic freezing (N) combined with osmo-microwave-vacuum drying resulted in the largest color changes of fruits and the highest thermal conductivity. Sonicated and convectively frozen (SF) fruits were characterized by the highest thermal diffusivity. Sonication (S), convective freezing (F) and their combination (SF) significantly reduced the volumetric heat capacity of cranberry fruits.

scholarly journals Effects of microwave power and slice thickness on fiber and ash contents of dried sweet potato (Ipomoea batata)

2020 ◽  
Vol 39 (3) ◽  
Author(s):  
C.O. Nwajinka ◽  
E.O. Okonjo ◽  
D.O. Amaefule ◽  
D.C. Okpala
Keyword(s):  
Moisture Content ◽  
Response Surface ◽  
Sweet Potato ◽  
Microwave Power ◽  
Initial Moisture Content ◽  
Microwave Oven ◽  
Microwave Drying ◽  
Average Moisture Content ◽  
Slice Thickness ◽  
Potato Slices

Investigation of microwave drying of sweet potato slices was conducted at microwave oven power settings of 90, 100, 120 Watts and slice thicknesses of 3mm, 4mm and 6mm using Fourier models and response surface methods. The slice samples dried from initial moisture content of 70.71𝒈𝒘𝒂𝒕𝒆𝒓/𝒈𝒅𝒓𝒚 𝒎𝒂𝒕𝒕𝒆𝒓 to 12.7𝒈𝒘𝒂𝒕𝒆𝒓/𝒈𝒅𝒓𝒚 𝒎𝒂𝒕𝒕𝒆𝒓 final (equilibrium) moisture content in the microwave oven. Fourier models adequately fitted the drying data with the following values of the fit parameters: MBE= 0.00002943 to 0.000645, R² = 0.9987 to 1, RMSE = 0.00384 to 0.01692. Effective moisture diffusion coefficient (𝑫𝒆) of the samples ranged from 𝟏.𝟎𝟖𝟐𝟐 × 𝟏𝟎−𝟑m2/s to 𝟖.𝟑𝟖𝟏𝟐 × 𝟏𝟎−𝟑 m2/s. Analysis of Variance (ANOVA) was used to analyze the effect of drying conditions on the samples parameters at 95% ( p<0.05). The results showed that slice thickness and microwave power have significant effects on the ash and fiber contents of the dried potato samples. At the microwave power of 90 W and slice thickness of 4 mm the values of Fiber and Ash retained in the dried sweet potato samples were optimal at 4.30% and 2.50% respectively, after drying for 390 minutes to an average moisture content of 14.2 gH2O/gdm. Optimized equations for predicting the percent ash and fiber contents at combined factors of microwave power and slice thickness were developed using Response Surface Methodology (RSM) at 95% confidence bound. The coefficients of determination (R2) for the models are 0.7333 and 0.9655 for fiber and ash respectively. These are indications that the models can be used to predict the two food components of microwave dried potato slices. Keywords: RSM, Fourier Model, Microwave, Sweet Potato, Ash, Fiber

scholarly journals Potential of microwave drying technology for increase drying rate and physical quality of kaffir lime (Citrus hystrix DC) leaves

2021 ◽  
Vol 924 (1) ◽  
pp. 012045
Author(s):  
F Su’aidah ◽  
I Taruna
Keyword(s):  
Moisture Content ◽  
Power Level ◽  
Preference Test ◽  
Color Difference ◽  
Microwave Drying ◽  
Drying Rate ◽  
Physical Quality ◽  
Oven Drying ◽  
Drying Rates

Abstract The effects of microwave power on microwave drying rates and the physical quality of kaffir lime leaves were studied. Three power levels were used in this study, high (723 watts), medium (537 watts), and low (420 watts). The moisture content, drying rate, color (L, a, b), and organoleptic parameters of each power level will be compared with the oven drying method (60°C). The result shows that the final moisture content of the high, medium, and low power of microwave drying are 6.06, 4.26%, and 6.16%db respectively, which is lower than oven drying, 16.62%db. Besides, the drying rate of microwave drying is 26.39-48.71%db/minute, higher than oven drying 0.32%db/minute. Dried kaffir lime leaves with medium level power (537 watt) has the lowest color difference (ΔE = 1.0 ± 0.29) compared to fresh leaves. While, the color and aromatic preference test dried kaffir lime leaves by microwave drying was preferable than oven drying.

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