Influence of pulsed electric field (PEF) pre-treatment on the convective drying kinetics of onions

The transition to an efficient economy and efficient production requires building the foundations for the development of energy efficient technologies and the drying of biomaterials to convert them into useful products. The purpose of this work is to analyze the effectiveness of pretreatment with a pulsed electric field (PEF) in the process of convective drying of biomaterials. The PEF was processed with electric field strength of 2, 4 and 6 kV/cm, the number of pulses 500, with a pulse duration of 50 ?s. Based on the electrical conductivity data of the biomaterial, the index of the disintegration 56% was determined before and after the PEF treatment, which confirms the existence of an electroporation mechanism of the material structure. The drying process is presented with a description of various mathematical models. PEF pre-treatment with the parameters of electric field strength 4 and 6 kV / cm and the number of impulses 500 allowed to reduce the drying time by 13.8% for the value E = 0.02. Total time spent on the drying process reduced by 20-25 minutes. It should be noted that the total energy spent on PEF pre-treatment (<150 W / kg) compared with the energy spent on the drying process is incommensurably small. Statistical analysis of the considered mathematical models showed good convergence of most models with experimental data. The considered technology of pretreatment of PEF can ensure the effective processing of biomaterials in the required amount to obtain high-quality and safe products. Obtained data of the kinetics process can be used to the mathematical model of the drying process design with the use of preliminary treatment processing.

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Applicability of Pulsed Electric Field (PEF) Pre-Treatment for a Convective Two-Step Drying Process

Foods ◽

10.3390/foods9040512 ◽

2020 ◽

Vol 9 (4) ◽

pp. 512 ◽

Cited By ~ 3

Author(s):

Robin Ostermeier ◽

Oleksii Parniakov ◽

Stefan Töpfl ◽

Henry Jäger

Keyword(s):

Electric Field ◽

Pyruvic Acid ◽

Acid Content ◽

Pulsed Electric Field ◽

Convective Drying ◽

Quality Analysis ◽

Drying Process ◽

Drying Time ◽

Treated Sample ◽

Pre Treatment

Available literature and previous studies focus on the Pulsed Electric Field (PEF) parameters influencing the drying process of fruit and vegetable tissue. This study investigates the applicability of PEF pre-treatment considering the industrial-scale drying conditions of onions and related quality parameters of the final product. First, the influence of the PEF treatment (W = 4.0 kJ/kg, E = 1.07 kV/cm) on the convective drying was investigated for samples dried at constant temperatures (65, 75, and 85 °C) and drying profiles (85/55, 85/65, and 85/75 °C). These trials were performed along with the determination of the breakpoint to assure an industrial drying profile with varying temperatures. A reduction in drying time of 32% was achieved by applying PEF prior to drying at profile 85/65 °C (target moisture ≤7%). The effective water diffusion coefficient for the last drying section has been increased from 1.99 × 10−10 m2/s to 3.48 × 10−10 m2/s in the PEF-treated tissue. In case of the 85/65 °C drying profile, the PEF-treated sample showed the highest benefits in terms of process efficiency and quality compared to the untreated sample. A quality analysis was performed considering the colour, amount of blisters, pyruvic acid content, and the rehydration behavior comparing the untreated and PEF-treated sample. The PEF-treated sample showed practically no blisters and a 14.5% higher pyruvic acid content. Moreover, the rehydration coefficient was 47% higher when applying PEF prior to drying.

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Effect of Pulsed Electric Field on the Osmotic Dehydration and Mass Transfer Kinetics of Apple Tissue

Drying Technology ◽

10.1081/drt-200054144 ◽

2005 ◽

Vol 23 (3) ◽

pp. 581-595 ◽

Cited By ~ 42

Author(s):

Ezzeddine Amami ◽

Eugene Vorobiev ◽

Nabil Kechaou

Keyword(s):

Mass Transfer ◽

Electric Field ◽

Osmotic Dehydration ◽

Pulsed Electric Field ◽

Mass Transfer Kinetics ◽

Apple Tissue ◽

Kinetics Of

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Effect of ultrasound pre-treatment on the drying kinetics of brown seaweed Ascophyllum nodosum

Ultrasonics Sonochemistry ◽

10.1016/j.ultsonch.2014.10.001 ◽

2015 ◽

Vol 23 ◽

pp. 302-307 ◽

Cited By ~ 55

Author(s):

Shekhar U. Kadam ◽

Brijesh K. Tiwari ◽

Colm P. O’Donnell

Keyword(s):

Brown Seaweed ◽

Ascophyllum Nodosum ◽

Drying Kinetics ◽

Pre Treatment ◽

Kinetics Of

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Mathematical modeling of pequi pulp drying and effective diffusivity determination

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v21n7p493-498 ◽

2017 ◽

Vol 21 (7) ◽

pp. 493-498 ◽

Cited By ~ 3

Author(s):

Elisabete P. de Sousa ◽

Rossana M. F. de Figueirêdo ◽

Josivanda P. Gomes ◽

Alexandre J. de M. Queiroz ◽

Deise S. de Castro ◽

...

Keyword(s):

Experimental Data ◽

Effective Diffusivity ◽

Drying Kinetics ◽

Convective Drying ◽

Drying Time ◽

Air Speed ◽

Drying Curves ◽

Increasing Temperature ◽

Kinetics Of ◽

Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

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