Effect of microwave, infrared, and convection hot-air on drying kinetics and quality properties of okra pods

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hany S. EL-Mesery ◽  
Mona A. Elabd
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Drying Methods ◽  
Air Velocity ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Shrinkage Ratio ◽  
Hot Air

Abstract Okra pods were dried using the following drying regimes; microwave (MWD), infrared (IRD) and convective hot-air drying (CHD). The objective of this investigate was to report the influences of drying methods on okra quality under different drying conditions. Data analysis showed that rehydration ratio and colour change increased with increase in drying air temperature and air velocity while specific energy consumption and shrinkage ratio decreased with increase in drying air temperature under (CHD). The rehydration ratio and colour of dried okra increased with increase in both infrared intensity but it also increased with a decrease in air velocity under (IRD). In the MWD method, drying time, specific energy consumption and shrinkage ratio decreased with increases in microwave power while the rehydration ratio and colour increased. Optimum drying period, specific energy consumption, colour, shrinkage and rehydration ratio were obtained for microwave drying. The model of Midilli et al. is the greatest for describing the drying curves of okra under all the drying processing conditions.

scholarly journals Determination of drying kinetics, specific energy consumption, shrinkage, and colour properties of pomegranate arils submitted to microwave and convective drying

2021 ◽  
Vol 6 (1) ◽  
pp. 230-242
Author(s):  
Mohammad Kaveh ◽  
Iman Golpour ◽  
João Carlos Gonçalves ◽  
Sara Ghafouri ◽  
Raquel Guiné
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Drying Kinetics ◽  
Drying Methods ◽  
Colour Properties ◽  
Drying Time ◽  
Effective Moisture ◽  
Pomegranate Arils

Abstract In this study, the drying kinetics, effective moisture diffusivity (D eff), specific energy consumption (SEC), colour, and shrinkage (S b) of pomegranate arils were compared when dried by convective (CV) drying and microwave (MW) drying. The experiments were performed at air temperature of 50, 60, and 70°C and air velocity of 1 m/s for CV drying and 270, 450, and 630 W for MW drying. The results showed that increasing air temperature and MW power increased the D eff. The calculations demonstrated that the maximum D eff for pomegranate arils was obtained for MW drying (630 W). Maximum SEC for pomegranate arils in the CV dryer was 145.12 kWh/kg, whereas in the MW dryer was 35.42 kWh/kg. In MW dryer, the lowest values of colour change and shrinkage were 6.77 and 50.5%, respectively. Comprehensive comparison of the different drying methods (MW and CV) revealed that MW drying had best drying performance for pomegranate arils, considering the drying time, effective moisture diffusion, SEC, colour, and shrinkage.

scholarly journals Analysis on Photovoltaic Energy-Assisted Drying of Green Peas

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Onur Taşkın ◽  
Nazmi İzli ◽  
Ali Vardar
Keyword(s):  
Energy Consumption ◽  
Moisture Content ◽  
Air Temperature ◽  
Specific Energy Consumption ◽  
Initial Moisture Content ◽  
Air Velocity ◽  
Rehydration Ratio ◽  
Total Energy Consumption ◽  
Photovoltaic Energy ◽  
Green Peas

A photovoltaic energy-assisted industrial dryer has been analyzed. The dryer has been tested in various weather and working conditions with 3 kg of green peas from 75.6% initial moisture content to 20% final moisture content (w.b.). The effect of various drying air temperatures at three levels (40, 50, and 60°C) and two distinct air velocities (3 m/s and 4 m/s) was examined. Drying performance was assessed with regard to criteria including drying kinetics, specific and total energy consumption, and color and rehydration ratio. The results have proved that total drying duration reduces as air velocity rate and drying air temperature raise. Relying upon the drying durations, the generation performances of photovoltaic panels were between 5.261 and 3.953 W. On the other part, energy consumptions of dryer were between 37.417 and 28.111 W. The best specific energy consumption was detected in 50°C at 3 m/s for 600 minutes with 7.616 kWh/kg. All drying conditions caused darkening as color parameters. Rehydration assays have showed that rehydrated green peas attained higher capacity with raised air temperature and air velocity.

Optimization of Pistachio Nut Drying in a Fluidized Bed Dryer with Microwave Pretreatment Applying Response Surface Methodology

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Reza Amiri Chayjan ◽  
Mohammad Kaveh ◽  
Nesa Dibagar ◽  
Moein Zarrin Nejad
Keyword(s):  
Response Surface Methodology ◽  
Energy Consumption ◽  
Fluidized Bed ◽  
Air Temperature ◽  
Specific Energy ◽  
Color Change ◽  
Specific Energy Consumption ◽  
Air Velocity ◽  
Fluidized Bed Dryer ◽  
Total Color Change

Abstract Thin-layer drying kinetics of pistachio nuts were examined experimentally as a function of drying conditions in a fluidized bed dryer with microwave pretreatment. Four drying specifications of diffusivity, shrinkage, specific energy consumption and total color change were calculated and the effects of parameters were studied. Numerous experimentations were conducted at three levels of air temperature (40, 55, 70 °C), air velocity (1.2, 2.93, 4.01 m/s), and microwave power (270, 450, 630 W). The variation ranges of diffusivity, shrinkage, energy consumption and color change were recorded from 5.01×10–10 to 5.07×10–9 m2/s, from 26.95 % to 13.13 %, from 1.04 to 9.23 kWh and from 10.44 to 17.17, respectively. According to response surface methodology, optimum condition of drying process occurred at microwave power of 630, air temperature of 70 ˚C, and air velocity of 1.2 m/s. In this optimum point, the values of diffusivity, shrinkage, specific energy consumption and total color change were 4.865×10–9, 14.22 %, 2.164 kWh and 12.312, respectively.

scholarly journals Evaluation of the Changes in Thermal, Qualitative, and Antioxidant Properties of Terebinth (Pistacia atlantica) Fruit under Different Drying Methods

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1378
Author(s):  
Yousef Abbaspour-Gilandeh ◽  
Mohammad Kaveh ◽  
Hamideh Fatemi ◽  
José Luis Hernández-Hernández ◽  
Alejandro Fuentes-Penna ◽  
...  
Keyword(s):  
Specific Energy Consumption ◽  
Antioxidant Properties ◽  
Microwave Drying ◽  
Total Phenol Content ◽  
Drying Methods ◽  
Drying Method ◽  
Flavonoid Content ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Hot Air

This study aims to investigate the effect of different drying methods on the thermal, qualitative, and antioxidant properties and pH of terebinth. To perform the experiments in this study, the hot air (HA), infrared (IR), microwave (MW), hot air–infrared (IR–HA), and hot air–microwave drying (MW–HA) methods were considered. The results showed that the minimum drying time was obtained by the hot air–microwave (MW–HA) method. However, the lowest specific energy consumption (SEC) and the highest energy efficiency (ηe) were obtained by the MW method. Considering the color criteria, the best method was obtained by the MW–HA method. The highest amount of rehydration ratio (RR) and the lowest shrinkage (Sb) of the dried terebinth samples were obtained using the MW dryer compared with other drying methods. The MW and MW–HA methods resulted in higher contents of total phenol content (TPC), total flavonoid content (TFC), and antioxidant capacity (AntiOX) than other methods. According to the results of this study, the most effective drying method for terebinth was determined to be the MW and MW-HA methods.

Effects of Drying Conditions of Fixed Bed Longan Drying on Optimal Bed Thickness

2007 ◽  
Author(s):  
Aree Achariyaviriya ◽  
Paradorn Nuthong
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Flow Rate ◽  
Specific Energy ◽  
Air Flow ◽  
Specific Energy Consumption ◽  
Air Flow Rate ◽  
Drying Time ◽  
Bed Thickness ◽  
Drying Conditions

In this work, it is presented a study of the effects of drying conditions on the optimal bed thickness of the whole longan. The criteria for evaluation of the drying process are specific energy consumption and drying time which the difference of moisture between top and bottom of drying chamber is less than 10%dry basis. The mathematical model is developed for finding the effects of the drying conditions on the optimal bed thickness. The drying conditions are drying air temperature, specific air flow rate, and fraction of recycled air. Experimental data were compared with the simulated results to verify the model. Furthermore, the sensitivity analysis of the fraction of air recycled, drying air temperature, specific airflow rate, initial moisture content, and bed thickness of longan are study. The results showed that there was good agreement between the simulated drying rate and those experimentally observed. In addition, there was a well agreement with respect to the shapes of the drying air temperature and product temperature profiles. From the simulated results, the optimal bed thickness of 40 cm, the specific energy consumption of 10.56 MJ/kg-water and drying time of 64.2 h were found. The responsive conditions were drying air temperature of 75°C, the fraction of recycled air of 90%, and the specific air flow rate of 73 kg-dry air/h-kg dry longan.

scholarly journals Comparative Study of Hot Air Drying and Microwave Drying for Dewatered Sludge

2021 ◽  
Author(s):  
Wittawat Wulyapash ◽  
Awassada Phongphiphat ◽  
Sirintornthep Towprayoon
Keyword(s):  
Microwave Power ◽  
Specific Energy Consumption ◽  
Microwave Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Dewatered Sludge ◽  
Dried Sludge ◽  
Seafood Processing

Abstract Large amounts of sludge are generated from wastewater treatment in seafood processing industries. Most of the dewatered sludge in Thailand is not utilized and disposed by landfilling. The dried sludge utilization as refuse-derived fuel (RDF) is an alternative solution due to the gross calorific value (GCV), which is greater than 21.9 MJ/kg. However, the key obstacle is its high moisture content of 87.4% (wet basis). Therefore, drying methods using hot air and microwave techniques were investigated for preparing dried sludge. The effects of hot air temperatures (100-150 °C) and microwave power levels (100-800 W) were compared on drying kinetics, specific energy consumption (SEC), and characteristics of the dried products. The results showed that drying times were decreased by increasing the hot air temperatures. In the same way, the increase in microwave power levels decreased the drying time. The application of microwaves contributed to reducing the drying time by more than 46% compared to the hot air. The reduction of drying times resulted in the saving SEC. The GCV of the dried sludge decreased with the decrease in the volatile matter (VM) due to the high component of VM as 79.5-80.3% (dry ash-free basis). The sludge dried by the microwaves showed a lower GCV than the hot air products. However, dried sludges still had high GCV (≥ 20.8 MJ/kg). Furthermore, the minimal variation of the product characteristics demonstrated that the microwave technique could be applied as an alternative drying method with a rapid process compared to the conventional hot air technique.

Evaluation of specific energy consumption and GHG emissions for different drying methods (Case study: Pistacia Atlantica)

2020 ◽  
Vol 259 ◽  
pp. 120963 ◽  
Author(s):  
Mohammad Kaveh ◽  
Reza Amiri Chayjan ◽  
Ebrahim Taghinezhad ◽  
Vali Rasooli Sharabiani ◽  
Ali Motevali
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Ghg Emissions ◽  
Drying Methods ◽  
Pistacia Atlantica

scholarly journals Hybrid Drying of Murraya koenigii Leaves: Energy Consumption, Antioxidant Capacity, Profiling of Volatile Compounds and Quality Studies

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 240 ◽  
Author(s):  
Choong Oon Choo ◽  
Bee Lin Chua ◽  
Adam Figiel ◽  
Klaudiusz Jałoszyński ◽  
Aneta Wojdyło ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Antioxidant Capacity ◽  
Volatile Compounds ◽  
Water Activity ◽  
Specific Energy ◽  
Activity Analysis ◽  
Drying Methods ◽  
Murraya Koenigii ◽  
Hot Air ◽  
Colour Parameters

This study aims to reduce the amount of specific energy consumed during the drying of fresh Murraya koenigii leaves by comparing four drying methods: (1) convective hot-air drying (CD; 40, 50 and 60 °C); (2) single-stage microwave-vacuum drying (MVD; 6, 9 and 12 W/g); (3) two-stage convective hot-air pre-drying followed by microwave-vacuum finishing–drying (CPD-MVFD; 50 °C, 9 W/g); and (4) freeze-drying as a control in the analysis sections. The drying kinetics were also modelled using thin-layer models. The quality parameters of dried M. koenigii leaves were measured including total polyphenolic content (TPC), antioxidant capacity (ABTS and FRAP), profiling of volatile compounds, colour analysis and water activity analysis. Results showed that CPD-MVFD effectively reduced the specific energy consumption of CD at 50 °C by 67.3% in terms of kilojoules per gram of fresh weight and 48.9% in terms of kilojoules per gram of water. The modified Page model demonstrated excellent fitting to the empirical data obtained. FD showed promising antioxidant activity. The major contributor of antioxidant capacity was TPC. The volatile compounds profiled by gas chromatography-mass spectrometry, namely, β-phellandrene (31%), α-pinene (19.9%), and sabinene (16%) were identified as the major compounds of dried M. koenigii leaves. Colour analysis showed MVD’s high performance in preserving the colour parameters of M. koenigii leaves under all conditions. The colour parameters were correlated to the antioxidant capacity and TPC. Water activity analysis showed that the water activity of M. koenigii leaves for all drying methods indicating that the conditions were microbiologically and shelf-stable. Pearson correlation showed the colour parameters of the leaves had a strong correlation to TPC. Overall, MVD showed promising energy consumption reduction and recovery in TPC and volatile compounds.

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