scholarly journals Microwave and steam blanching as pre-treatments before air drying of Moringa oleifera leaves

2020 ◽  
Vol 51 (4) ◽  
pp. 200-208
Author(s):  
Ernest Ekow Abano ◽  
Robert Sarpong Amoah ◽  
Catherine Mbabazi
Keyword(s):  
Microwave Power ◽  
Moringa Oleifera ◽  
Drying Kinetics ◽  
Drying Time ◽  
Air Drying ◽  
Moringa Oleifera Leaves ◽  
Pre Treatment ◽  
Microwave Time ◽  
Drying Conditions ◽  
Short Time

The objective of this work was to identify the optimal drying conditions to produce better quality dried Moringa oleifera leaves with the best drying kinetics using microwave and steam blanching pre-treatments prior to hot air drying. For this purpose, the effect of microwave power, microwave time, steaming time, and air temperature on drying kinetics and quality of Moringa leaves was evaluated using the response surface methodology. In order to achieve a moisture content of 8.0% kg H2O/kg dry matter, the optimal conditions identified were a steaming time of 2.58 min (2 min 35 sec) prior to air drying at 70°C and a microwave power of 270 W for 3 min, followed by air drying at 70°C. At this optimal condition, a confirmation test for steam-assisted air drying gave a drying time (DT) of 53 min, ascorbic acid (AA) of 2.49 mg/g, and the antioxidant activity (AOA) of 67.244% inhibition. For microwave-assisted air drying, the confirmation experiment gave a DT of 43 min, AA of 2.699 mg/g, and AOA of 74.46% inhibition. Both pre-treatments before air drying followed a falling rate drying period at the initial stages and later a constant rate drying period. Our results showed that microwave blanching should be considered as a pre-treatment in industrial production of Moringa leaves to produce better quality dried products in a relatively short time.

Influence of Microwave Osmotic Dehydration Pre-Treatment on the Second Stage of Air-Drying Kinetics of Apples

2011 ◽  
Vol 7 (3) ◽  
Author(s):  
Elham Azarpahzooh ◽  
Hosahalli S. Ramaswamy
Keyword(s):  
Energy Savings ◽  
Osmotic Dehydration ◽  
Sucrose Concentration ◽  
Drying Kinetics ◽  
Drying Time ◽  
Air Drying ◽  
Second Stage ◽  
Freeze Dried ◽  
Pre Treatment ◽  
Kinetics Of

The effect of microwave-osmotic dehydration pre-treatment under continuous flow medium spray (MWODS) conditions on the second stage air-drying kinetics of apple (Red Gala) cylinders was evaluated. MWODS pre-treatment was carried out using a response surface methodology involving 5-levels of sucrose concentration (33-66.8°B), temperature (33-66.8°C) and contact time (5-55 min). Drying time and coefficient of moisture diffusion (Dm) and coefficient of moisture infusion (Im) during rehydration were evaluated as responses and the results were compared with their air-dried (AD) (worst scenario) and freeze-dried (FD) (best scenario) counterparts without the osmotic treatments. The diffusion and infusion coefficients were based on the solution of Fick's diffusion model. Empirical models developed for all response variables were significant (P ? 0.001) and the lack of fit was not significant (P > 0.05). MWODS pre-treatments significantly influenced the Dm values and reduced the air-drying time of apples by 30-65 percent in comparison with untreated apple thereby providing opportunity for better energy savings. On the other hand, the values of Im during the rehydration process were highest for the freeze-dried samples followed by apples air-dried after MWODS treatment, and the least for the untreated air-dried samples.

Microwave Assisted Convective Air Drying of Sugarloaf Pineapples (Ananas Comosus)

2021 ◽  
Vol 37 (5) ◽  
pp. 763-774
Author(s):  
Ernest Ekow Abano
Keyword(s):  
Air Temperature ◽  
Microwave Power ◽  
Moisture Diffusivity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Microwave Assisted ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Conditions

HighlightsMicrowave pretreatment before drying reduced drying time significantly.Microwave-assisted drying increased the effective moisture diffusivity coefficient.Microwave pretreatment before convective hot-air drying improved quality parameters.The Middili et al. (2002) model best fitted the microwave-assisted drying of sugarloaf pineapples.Abstract. This study’s objective was to provide the optimum drying conditions to produce quality dried sugarloaf pineapples using microwave pretreatments before the conventional hot air drying. For this, the effect of microwave power (385 to 697 W), microwave time (2 to 4 min), and air temperature (50°C to 70°C) on the drying kinetics and quality of sugarloaf pineapple were evaluated using the Box Behnken response surface methodology. To reach a 17.44±0.09% kg/kg dry matter moisture content, we found the optimum drying conditions for sugarloaf pineapples to be 697 W microwave power for 2.26 min before convective hot air drying at a temperature of 64.75°C. The predicted drying time, ascorbic acid content, and browning index were 13.68 h, 20.89 mg/100 g, and 0.099 Abs unit at this optimum condition, respectively. The pineapple slices’ effective moisture removal rate pretreated with microwave before drying was higher than the control and was between 6.42 × 10-10 m2/s and 11.82 × 10-10 m2/s while ones without a microwave were between 3.54 × 10-10 m2/s and 8.78 × 10-10 m2/s for drying at air temperature between 50°C and 70°C. It was discovered that the Midilli et al. (2002) model was the most appropriate thin layer model for microwave-assisted drying of sugarloaf pineapples. The pineapple slices’ drying rate potential generally increased with microwave power and pretreatments time but not the corresponding increase in the air temperature. Drying time for microwave-assisted drying was in the range of 11 to 20 h, while the ones without microwaves were between 18 and 24 h. Therefore, microwaves should be considered a pretreatment step to the industrial production of sugarloaf pineapple to reduce drying time and produce better quality products. Keywords: Drying, Hot air, Microwave, Moisture diffusivity, Sugarloaf pineapple.

INVESTIGATION OF POTATO DRYING KINETICS AND QUALITY PARAMETERS APPLYING ULTRASOUND PRE-TREATMENTS

2020 ◽  
Vol 50 (4) ◽  
pp. 261-269
Author(s):  
Nazmi Izli ◽  
Ahmet Polat
Keyword(s):  
Treatment Time ◽  
Ph Value ◽  
Quality Parameters ◽  
Drying Kinetics ◽  
Slice Thickness ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Pre Treatment ◽  
Brix Value ◽  
Drying Conditions

In this study, the effect of ultrasound pre-treatment on quality parameters (colour, rehydration, pH and °Brix) of potato samples was investigated. In addition, drying kinetics of potato samples were formed and 10 mathematical models were applied to experimental data to select the best thin-layer drying model in drying processes. Two different slices of potato samples (2 and 4 mm) were ultrasound pre-treated for 0, 20 and 40 min before drying. Drying was carried out in a modified oven at 60 and 70 °C at an air velocity of 1 m/s. As the ultrasound pre-treatment time applied to the samples increased, the drying time of the product decreased. The drying rate decreased with increasing product slice thickness. A decrease in yellowness (b*) values was observed with the effect of drying conditions. Rehydration values of potatoes under all drying conditions ranged from 2.856 to 2.640. The highest pH value was determined in potato samples dried at 60 °C with a thickness of 4 mm without ultrasound pre-treatment. The closest °Brix value to the fresh product was observed in 2 mm thick potato samples dried at 70 °C and treated with ultrasound for 40 min. In this study, it has been determined that ultrasound pre-treatment can be used as a different method for drying potato with hot air.

scholarly journals Optimization of microwave-assisted alkaline pre-treatment method for the cellulolytic fermentation of abaca stripping waste into glucose

2019 ◽  
Vol 268 ◽  
pp. 06012
Author(s):  
Glanelle Ivy Cea ◽  
Julius Ryan Manlangit ◽  
Marianne Reverente ◽  
John Raymond Barajas
Keyword(s):  
Microwave Power ◽  
Treatment Method ◽  
The Philippines ◽  
Optimum Conditions ◽  
Glucose Yield ◽  
Independent Variables ◽  
Precursor Material ◽  
Pre Treatment ◽  
Microwave Time ◽  
Export Product

Abaca fiber remains a vital export product that contributes primarily to the continuous economic growth of the Philippines. However, the voluminous amount of byproducts generated has consistently caused setbacks which often result to major losses to the growing abaca industry in the country. In an attempt to provide a practical solution to the emerging problem, we investigate the utilization of abaca stripping waste (ASW) as a precursor material to produce bioethanol. We test the extent of conversion of the hemicellulose-rich by product to glucose. A box-behnken experimental design was used to obtain the optimal conditions in the conversion process. Alkaline concentration (%), microwave power (W), and microwave time (min) were found to have significant influence on the glucose yield. Actual values of these independent variables were chosen on the basis of preliminary experimental results. Optimum conditions using ridge analysis were found to be: alkaline concentration 2.55%, microwave power 124.0 W, and microwave time at 1.0 min. Conversion to glucose was also performed at optimum conditions. In conclusion, a high glucose yield obtained which is suitable for bioethanol fermentation presents evidence encouraging the utilization of abaca stripping waste to produce high value products.

Single Layer Drying Behavior of Apple Slices in a Microwave Dryer

2011 ◽  
Vol 312-315 ◽  
pp. 842-847 ◽  
Author(s):  
Soner Çelen ◽  
Kamil Kahveci ◽  
Ugur Akyol
Keyword(s):  
Microwave Power ◽  
Colour Change ◽  
Single Layer ◽  
Drying Time ◽  
Apple Slices ◽  
Drying Behavior ◽  
Drying Behaviour ◽  
Drying Conditions ◽  
Mean Square Errors ◽  
Microwave Dryer

In this study, the drying behaviour of single layer apple slices of 5mm thickness in a microwave dryer was investigated experimentally for four different microwave power levels (90 W, 180 W, 360 W and 600 W) and suitability of drying models available in the literature in simulating the drying behaviour of apple slices was determined by statistical analysis. The performance of these models was determined by comparing the coefficients of determination (R), reduced chi-squares (χ2) and root mean square errors (RMSE) of the models. The results show that drying time and energy consumption decreases considerably with increasing microwave power. The results also show that, among of the models proposed, the Verma et al. model gives the best fit with experimental data for all drying conditions considered. In order to determine the colour change of apple, a colour meter was also used in this study and found that L* and a* values were not significantly different from the values of the fresh apples.

Ultrasound as Pre-Treatment for Drying of Genipap (Genipa americana L.)

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Fabiano An. Fernandes ◽  
Sueli Rodrigues
Keyword(s):  
Ultrasonic Treatment ◽  
Sugar Content ◽  
Drying Process ◽  
Drying Time ◽  
Air Drying ◽  
Tropical Fruit ◽  
Dried Fruits ◽  
Water Diffusivity ◽  
Pre Treatment

Abstract Genipap (Genipa americana L.) is an exotic tropical fruit that can be used in production of sweets, liqueurs, and several other foodstuffs. In this work the effect of ultrasonic pre-treatment prior to air-drying on dehydration of genipap was investigated. The study allowed estimating the water diffusivity in the air-drying process for genipaps submitted to ultrasound. Results showed that the water diffusivity increased after application of ultrasound and that the overall drying time was reduced by 28.2%. During the ultrasonic treatment, genipaps lost sugar showing that the ultrasonic pre-treatment can be a valuable process to produce dried fruits with lower sugar content.

Effect of Air Velocity and Temperature on the Drying Kinetics of Drumstick Leaves (Moringa Oleifera)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Monica Premi ◽  
Harish Sharma ◽  
Ashutosh Upadhyay
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Moringa Oleifera ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Kinetics Of

Abstract The present study examines the effect of air velocity on drying kinetics of the drumstick leaves in a forced convective dryer. The drumstick leaves were dried in the temperature range of 50–800 C, at different air velocity (Dv) of 0.5 and 1.3 m/s. The results indicated that drying temperature and air velocity are the factors in controlling the drying rate. Experimental data obtained for the samples for color, drying rate and drying time proved that air velocity of 1.3 m/s yielded the product superior in terms of both quality and energy efficiency as compared to the samples at 0.5 m/s. Activation energy for drumstick leaves dried with air velocity, 0.5 and 1.3 m/s was 12.50 and 32.74 kJ/mol respectively. The activation energy relates similarly with the effective moisture diffusivity which also increased with increase in air velocity and temperature.

Artificial Neural Network Approach for Impingement Drying of Germinated Brown Rice Soaking with Turmeric Solution

2013 ◽  
Vol 372 ◽  
pp. 463-466
Author(s):  
Kiattisak Suntaro ◽  
Khwanruedi Sangchum ◽  
Supawan Tirawanichakul ◽  
Yutthana Tirawanichakul
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Moisture Content ◽  
Brown Rice ◽  
Measured Data ◽  
Drying Kinetics ◽  
Drying Time ◽  
Rice Samples ◽  
Artificial Neural ◽  
Drying Conditions

The objectives of this research are to determine the evolution of moisture transfer for germinated Thai jasmine Khao Dawk Mali 105 (KDML105) brown rice variety using impingement drying by eight commonly empirical drying modeling and artificial neural network (ANN) method. The experiments were carried out with drying temperatures of 80-100°C, initial moisture content of KDML105 rice samples soaking with turmeric solution was of 54-55% dry-basis and the desired final moisture content for each drying conditions was fixed at 14-16% dry-basis. The air flow rate was fixed at 7.0 m/s. The measured data in each drying conditions were simulated for getting drying equation by non-linear regression analysis. The results showed that the rice soaking with herb turmeric solution had no effect to drying kinetics and the simulated data using empirical drying equation of Henderson model had the best fitting to all measured data (R2of 0.9978-0.9995 and RMSE of 0.0001441-0.000414). For applying ANN modeling approach, the drying temperature and drying time were considered as the input variables for the topology of neural network while the moisture ratio was the output layer. The simulation results concluded that the simulated values of the ANN model, which was not concerned with any complicated physical properties of grain rice kernels, could be used for prediction drying kinetics and was relatively high accuracy compared to those predicted results of empirical models. So the ANN method without any complicated properties related of rice samples can approach for good prediction their drying kinetics as well as the complicated drying simulations method.

scholarly journals Dried Figs Quality Improvement and Process Energy Savings by Combinatory Application of Osmotic Pretreatment and Conventional Air Drying

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1846
Author(s):  
Varvara Andreou ◽  
Ioanna Thanou ◽  
Marianna Giannoglou ◽  
Maria C. Giannakourou ◽  
George Katsaros
Keyword(s):  
Quality Improvement ◽  
Energy Savings ◽  
Osmotic Dehydration ◽  
Effective Diffusion ◽  
Drying Time ◽  
Air Drying ◽  
Solid Gain ◽  
Pre Treatment ◽  
Process Energy ◽  
Time And Energy

This study concerns the implementation of osmotic dehydration (OD) as a pre-treatment of air-drying in fig halves, aiming at drying acceleration, energy savings and product quality improvement. The effect of solid/liquid mass ratio, process temperature (25–45 °C) and duration (up to 300 min) on water activity (aw) and transport phenomena during OD, was modelled. The effective diffusion coefficients, drying time and energy consumption, were also calculated during air-drying at 50–70 °C. At optimum OD conditions (90 min, 45 °C), the highest water loss and solid gain ratio were achieved, while the aw (equal to an initial value 0.986) was decreased to 0.929. Air-drying time of OD- and control samples was estimated at 12 and 21 h, at 60 °C, respectively, decreasing the required energy by up to 31.1%. Quality of dried figs was systematically monitored during storage. OD-assisted air-drying led to a product of improved quality and extended shelf-life.

scholarly journals Influence of the temperature and ultrasound application in drying kinetics of apple skin

2018 ◽  
Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Carmen Rosselló ◽  
Ramón Peña
Keyword(s):  
Physical Structure ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Different Temperatures ◽  
Ultrasound Application ◽  
Quality Of Products ◽  
Drying Conditions ◽  
Kinetics Of ◽  
By Products

The great amount of waste produced by food industry contains interesting bioactive compounds. The extraction of these compounds requires the by-products previous stabilization being the convective drying one of most used techniques to this end. Drying conditions can affect both drying kinetics and final quality of products. The apple skin, byproduct of apple juice or cider industries, is rich in functional compounds such as polyphenols or vitamin C. The main goal of this contribution was to quantify the influence of temperature and ultrasound application in drying kinetics of apple skin. For this purpose, drying experiments at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) and without application of ultrasound were carried out. Drying kinetics were modelled by using a diffusion based model. As can be expected, the higher the temperature the faster the drying. Ultrasound application accelerated the process at every temperature tested being the influence slightly lower than found from the literature for other products. This can be attributed at the physical structure of the apple skin, less porous than the pulp. In any case, the application of ultrasound significantly reduced the drying time. Keywords: by-products; dehydration;diffusivity; mass transfer

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