Inversion of a numerical model to predict the effective moisture diffusivity of fruits during drying as a function of temperature and moisture content

During milling of cereal grains, bran which is separated from the starchy endosperm of the grain is a major by-product. In this study, milled sorghum residue was dried in a cabinet dryer under different conditions (temperature and air velocity). The obtained drying data were fitted into ten existing mathematical models and obtained the best model while, the effective moisture diffusivity and activation energy of the drying process was determined using Arrhenius type approach. The result shows that the initial moisture content obtained for the sorghum residue using standard oven drying method were 41.28 ± 0.33%, 49.52 ± 0.63 % and 47.06 ± 0.42 % on wet basis for the wet residue of variety A, B and C, respectively, at equilibrium point, the final moisture content of about 12.93 ± 0.14 – 14.31± 0.07 as temperature ranges from 40 oC to 70 oC and air velocity ranges from 0.8 m/s to 1.2 m/s. During the drying process, the drying rate falls more rapidly as it was initially high as a result of more moisture in the sorghum residue and the drying rate decreases slowly until reaching the reduced moisture content. The obtained values of effective moisture diffusivity (Deff) ranges between 9.89 x 10-10 and 22.21 x 10-10 m2/s, 9.45 x 10-10 and 20.62 x 10-10 m2/s and 8.56 x 10-10 and 20.76 x 10-10 m2/s for variety A, B and C, respectively. However, the result of the modelling shows that the drying characteristics of variety A and B of the sorghum residue can be predicted using Midilli et al. model while the drying behaviour of Variety C can be predicted using Hii et al. model.

Download Full-text

Far-Infrared Drying Characteristics of Mushroom Slices

Chemical Product and Process Modeling ◽

10.1515/cppm-2013-0035 ◽

2013 ◽

Vol 8 (2) ◽

pp. 107-117 ◽

Cited By ~ 15

Author(s):

Hosain Darvishi ◽

Gholamhassan Najafi ◽

Adel Hosainpour ◽

Jala Khodaei ◽

Mohsen Aazdbakht

Keyword(s):

Moisture Content ◽

Thin Layer ◽

Far Infrared ◽

Moisture Diffusivity ◽

Maximum Energy ◽

Effective Moisture Diffusivity ◽

Effect Of Temperature ◽

Infrared Drying ◽

Effective Moisture ◽

Thin Layer Drying

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.

Download Full-text

EFFECT OF DRYING KINETICS ON THE QUALITY OF THE GREEN CAPSICUM

Journal of medical pharmaceutical and allied sciences ◽

10.22270/jmpas.v10i4.1473 ◽

2021 ◽

Vol 10 (4) ◽

pp. 3464-3468

Author(s):

Madhumita Saha

Keyword(s):

Moisture Content ◽

Microwave Power ◽

Effective Diffusivity ◽

Kinetic Studies ◽

Moisture Diffusivity ◽

Effective Moisture Diffusivity ◽

Drying Time ◽

Effective Moisture ◽

Drying Behavior ◽

Drying Efficiency

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.

Download Full-text

Optimization and Prediction of the Drying and Quality of Turnip Slices by Convective-Infrared Dryer under Various Pretreatments by RSM and ANFIS Methods

Foods ◽

10.3390/foods10020284 ◽

2021 ◽

Vol 10 (2) ◽

pp. 284

Author(s):

Ebrahim Taghinezhad ◽

Mohammad Kaveh ◽

Antoni Szumny

Keyword(s):

Energy Efficiency ◽

Color Difference ◽

Moisture Diffusivity ◽

Effective Moisture Diffusivity ◽

Diffusivity Coefficient ◽

Drying Process ◽

Anfis Model ◽

Drying Time ◽

Effective Moisture ◽

Response Variables

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.

Download Full-text