scholarly journals EFFECT OF DRYING KINETICS ON THE QUALITY OF THE GREEN CAPSICUM

2021 ◽  
Vol 10 (4) ◽  
pp. 3464-3468
Author(s):  
Madhumita Saha

The effect of power (Watt) of microwave assistance drying on consumption of energy, drying efficiency and kinetic studies in green capsicum (Capsicum annum) was studied. For describing green capsicum drying behavior two mathematical models (Lewis model and Parabolic model) are used. Based on their root mean square error, χ2 and R2, values of predicted and experimental moisture content to models are compared. The drying time of green capsicum was decreased from 47 minutes to 22 minutes due to increasing power of microwave from 180 Watt to 900 Watt. The drying process was showing a falling rate period. In Lewis model the result shown most appropriate model for the study. For co-relation of moisture content with effective moisture diffusivity a third-order relationship was found. The effective moisture diffusivity of Green Capsicum samples increased as the moisture content decreased. Over the microwave power spectrum tested, the effective diffusivity ranged from 1.5 X 1012 m2/sec to 4.3 X 108 m2/sec, with an energy activation of 31.74 W/g. As microwave power and moisture content increased, so did energy efficiency.

2013 ◽  
Vol 27 (2) ◽  
pp. 127-132 ◽  
Author(s):  
H. Darvishi ◽  
M. Hadi Khoshtaghaza ◽  
G. Najafi ◽  
M. Zarein

Abstract The effect of the microwave-convective drying technique on the moisture ratio, drying rate, drying time, effective moisture diffusivity, microwave specific energy consumption, and energy efficiency of sunflower seedswere investigated.Drying took place in the falling rate period. Increasing the microwave power caused a significant decrease in the drying time. The drying data were fitted to four thin-layer drying models. The performance of these models was compared using the coefficient of determination, reduced chi-square and root mean square error between the observed and predicted moisture ratios. The results showed that the Page model was found to satisfactorily describe themicrowave-convective drying curves of sunflower seeds. The effective moisture diffusivity values were estimated from Fick diffusion model and varied from 1.73 10-7 to 4.76 10-7m2s-1. Increasing the microwave power resulted in a considerable increase in drying efficiency and a significant decrease in microwave specific energy consumption. The highest energy efficiency and the lowestmicrowave specific energy consumption were obtained at the microwave power of 300 W.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Ebrahim Taghinezhad ◽  
Mohammad Kaveh ◽  
Antoni Szumny

Drying can prolong the shelf life of a product by reducing microbial activities while facilitating its transportation and storage by decreasing the product weight and volume. The quality factors of the drying process are among the important issues in the drying of food and agricultural products. In this study, the effects of several independent variables such as the temperature of the drying air (50, 60, and 70 °C) and the thickness of the samples (2, 4, and 6 mm) were studied on the response variables including the quality indices (color difference and shrinkage) and drying factors (drying time, effective moisture diffusivity coefficient, specific energy consumption (SEC), energy efficiency and dryer efficiency) of the turnip slices dried by a hybrid convective-infrared (HCIR) dryer. Before drying, the samples were treated by three pretreatments: microwave (360 W for 2.5 min), ultrasonic (at 30 °C for 10 min) and blanching (at 90 °C for 2 min). The statistical analyses of the data and optimization of the drying process were achieved by the response surface method (RSM) and the response variables were predicted by the adaptive neuro-fuzzy inference system (ANFIS) model. The results indicated that an increase in the dryer temperature and a decline in the thickness of the sample can enhance the evaporation rate of the samples which will decrease the drying time (40–20 min), SEC (from 168.98 to 21.57 MJ/kg), color difference (from 50.59 to 15.38) and shrinkage (from 67.84% to 24.28%) while increasing the effective moisture diffusivity coefficient (from 1.007 × 10−9 to 8.11 × 10−9 m2/s), energy efficiency (from 0.89% to 15.23%) and dryer efficiency (from 2.11% to 21.2%). Compared to ultrasonic and blanching, microwave pretreatment increased the energy and drying efficiency; while the variations in the color and shrinkage were the lowest in the ultrasonic pretreatment. The optimal condition involved the temperature of 70 °C and sample thickness of 2 mm with the desirability above 0.89. The ANFIS model also managed to predict the response variables with R2 > 0.96.


Author(s):  
Magesh Ganesh Pillai ◽  
Iyyasamy Regupathi ◽  
Lima Rose Miranda ◽  
Thanapalan Murugesan

The drying characteristics of plaster of paris (POP) under microwave conditions at different microwave power input, initial moisture content, sample thickness and drying time were studied. Further the experimental data on moisture ratio of POP for different operating conditions were obtained and calculations were made using nine basic drying model equations. The appropriate model with modified constants and coefficients to represent the drying kinetics of POP was found through the analysis of the statistical analysis. The effective moisture diffusivity of the drying process was also computed for different experimental conditions and a relationship between the drying rate constant and the effective moisture diffusivity was obtained. The energy consumption for microwave drying of plaster of paris at different experimental conditions were also computed.


2016 ◽  
Vol 12 (5) ◽  
pp. 481-489 ◽  
Author(s):  
Daniel I. Onwude ◽  
Norhashila Hashim ◽  
Rimfiel B. Janius ◽  
Nazmi Nawi ◽  
Khalina Abdan

Abstract This study seeks to investigate the effects of temperature (50, 60, 70 and 80 °C) and material thickness (3, 5 and 7 mm), on the drying characteristics of pumpkin (Cucurbita moschata). Experimental data were used to estimate the effective moisture diffusivities and activation energy of pumpkin by using solutions of Fick’s second law of diffusion or its simplified form. The calculated value of moisture diffusivity with and without shrinkage effect varied from a minimum of 1.942 × 10–8 m2/s to a maximum of 9.196 × 10–8 m2/s, while that of activation energy varied from 5.02158 to 32.14542 kJ/mol with temperature ranging from 50 to 80 °C and slice thickness of 3 to 7 mm at constant air velocity of 1.16 m/s, respectively. The results indicated that with increasing temperature, and reduction of slice thickness, the drying time was reduced by more than 30 %. The effective moisture diffusivity increased with an increase in drying temperature with or without shrinkage effect. An increase in the activation energy was observed due to an increase in the slice thickness of the pumpkin samples.


2021 ◽  
Vol 51 (3) ◽  
pp. 173-178
Author(s):  
Fakhreddin Salehi ◽  
Maryam Satorabi

The objective of the current work was aimed to estimate the influence of novel edible coatings based on basil seed and xanthan gums, and infrared (IR) radiation power on the drying efficiency of coated peach slices were investigated in an IR dryer system. Moisture ratio data of IR drying of peach slices were fitted to 7 various empirical thin-layer equations. It was found that Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of coated peach slices with the lowest mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and standard error (SE) values and the highest correlation coefficient (r) value. The values of MSE, RMSE, and MAE for all experiments were in the ranges of 0.00017-0.00047, 0.013-0.022, and 0.011-0.018, respectively. The average drying time of uncoated peach slices, coated by xanthan gum and coated by basil seed gum were 52.78, 60.00, and 76.22 min, respectively. The average effective moisture diffusivity (Deff) of uncoated and coated peach slices with basil seed and xanthan gums increased from 2.18×10-9 m2/s to 4.56×10-9 m2/s with increasing IR lamp power from 150 W to 375 W.


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.


Author(s):  
Brijesh Srivastava ◽  
K. Padmeshore Singh ◽  
Wungshim Zimik

Oyster mushroom was treated with hot water and steam blanching prior to drying in cabinet dryer. A hot air cabinet dryer was used for drying mushroom at 40, 50, 60, 70 and 80°C temperatures. Solid loss was observed to be 25.46% and 3.32% (wb) during hot water and steam blanching, respectively. Highest drying rate was observed for hot water blanched mushroom followed by unblanched and steam blanched mushroom. This leads to more drying time for the steam blanched mushroom followed by the unblanched and hot water blanched mushroom for the same level of drying. The drying data was modeled for exponential and Page's drying model. Page's model was found to be better than the exponential model for the prediction of drying rate. The value of the model parameters of the exponential model was found to be higher than that of Page's model. The effective moisture diffusivity (De) was determined at different temperatures and found to be maximum for the hot water blanched mushroom and minimum for the steam blanched mushroom. The effective moisture diffusivity (De) increased with increase in temperature. The activation energy of hot water blanched, unblanched and steam blanched mushroom was estimated to be 25.324, 17.113 and 21.165 kJ/mol, respectively.


2014 ◽  
Vol 1036 ◽  
pp. 3-8
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević

In order to describe the internal moisture rate and to take all different mechanisms of moisture movement into account, it is suitable to use effective diffusivity as a measure of moisture rate, irrespectively of the mechanisms really involved. This means that all different mechanisms and driving forces for internal moisture transport are lumped together and introduced into effective moisture diffusivity. Hence, diffusion equations are retained and reused with the effective diffusivity coefficient as a measuring parameter of internal moisture ratio. In our previous studies we have presented the calculation method which assumed constant diffusivity. The next goal was to estimate effective diffusivity at various moisture contents, in a real case of non-linear drying curves, and to predict drying kinetic. In our last study we have developed a model for determination of the variable effective diffusivity and identification of the exact transition points between possible drying mechanisms. In this paper we have tried to develop more accurate tool for determination of time dependent effective moisture diffusivity. An analytical model and computing procedure were developed to evaluate mass transfer properties and describe drying kinetic of clay tiles having less clay fraction. The proposed procedure was validated with experimental drying data. Presented results have demonstrated that the proposed dying model can be applied for the accurate description of experimental drying kinetics and a reliable estimation of effective diffusivity.


2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Ganesh Lotanrao Visavale ◽  
Parag P Sutar ◽  
Bhaskar Narayan Thorat

A study on drying of two types of fish, viz., Bombay duck and Prawn, using the open sun, a solar cabinet, hot air and freeze drying was carried out. The fish were dried to 5–6% moisture content. The drying rates were calculated and drying data were fitted to the Page model, and on the basis of R2 and RMSE values it was found that the Page model describes satisfactorily the drying behavior of Bombay duck and Prawn. Also, effective moisture diffusivity values were calculated during fish drying by different methods. The values of the average effective moisture diffusivity of Bombay duck and Prawn were in the range of 1.01 × 10-9 to 1.51 × 10-9 m2 s-1and 0.21 × 10-9 to 0.31 × 10-9 m2 s-1, respectively. Freeze drying was found to provide the best quality of dehydrated product, which was as expected. Solar cabinet drying was found to be a low-energy intensive process compared to freeze and hot air drying, resulting in a dehydrated product with acceptable quality.


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