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

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 512 ◽  
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.

scholarly journals Pulsed electric field pre-treatment efficiency analysis in processes of biomaterials drying

2019 ◽  
Vol 80 (4) ◽  
pp. 49-54 ◽  
Author(s):  
I. A. Shorstkii ◽  
D. A. Khudyakov
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Mathematical Models ◽  
Electric Field Strength ◽  
Pulsed Electric Field ◽  
Convective Drying ◽  
Efficient Production ◽  
Drying Process ◽  
Drying Time ◽  
Pre Treatment

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.

scholarly journals The Impact of Pulsed Electric Field on the Extraction of Bioactive Compounds from Beetroot

Foods ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 244 ◽  
Author(s):  
Malgorzata Nowacka ◽  
Silvia Tappi ◽  
Artur Wiktor ◽  
Katarzyna Rybak ◽  
Agnieszka Miszczykowska ◽  
...  
Keyword(s):  
Electric Field ◽  
Bioactive Compounds ◽  
Control Sample ◽  
Pulsed Electric Field ◽  
Pulse Number ◽  
Cell Membrane Permeability ◽  
Mineral Salts ◽  
Treated Sample ◽  
Pre Treatment ◽  
The Impact

Beetroot is a root vegetable rich in different bioactive components, such as vitamins, minerals, phenolics, carotenoids, nitrate, ascorbic acids, and betalains, that can have a positive effect on human health. The aim of this work was to study the influence of the pulsed electric field (PEF) at different electric field strengths (4.38 and 6.25 kV/cm), pulse number 10–30, and energy input 0–12.5 kJ/kg as a pretreatment method on the extraction of betalains from beetroot. The obtained results showed that the application of PEF pre-treatment significantly (p < 0.05) influenced the efficiency of extraction of bioactive compounds from beetroot. The highest increase in the content of betalain compounds in the red beet’s extract (betanin by 329%, vulgaxanthin by 244%, compared to the control sample), was noted for 20 pulses of electric field at 4.38 kV/cm of strength. Treatment of the plant material with a PEF also resulted in an increase in the electrical conductivity compared to the non-treated sample due to the increase in cell membrane permeability, which was associated with leakage of substances able to conduct electricity, including mineral salts, into the intercellular space.

scholarly journals Pulsed electric field enhanced freeze-drying of apple tissue

2019 ◽  
Vol 37 (No. 6) ◽  
pp. 432-438 ◽  
Author(s):  
Yali Wu ◽  
Dongguang Zhang
Keyword(s):  
Electric Field ◽  
Freeze Drying ◽  
Effective Diffusion ◽  
Specific Energy Consumption ◽  
Pulsed Electric Field ◽  
Drying Process ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Effective Diffusion Coefficients ◽  
Apple Tissue

The influence of pulsed electric field (PEF) on freeze-drying of apple tissue was investigated. The freeze-drying was performed with different parameters of PEF treatment, and PEF treatment on the drying characters, microstructure, rehydration ratio, effective diffusion coefficient and hardness of apple tissue were discussed separately. The results indicated that PEF utilization as a pretreatment of apples enhances the drying process. The drying time was shortened by 17.73% at most, specific energy consumption decreased by 24.74% at most, and the rehydration ratio was improved by 65.22% at most for PEF treatment samples respectively, compared with the untreated samples. The effective diffusion coefficients varied from 2.60 × 10−8 m2/s to 4.20 × 10−8 m2/s for PEF pretreated samples, and was 2.40 × 10−8 m2/s for untreated samples drying at 75°C, the hardness of the untreated apple tissue was about 144.4 N which was decreased to 39.5–115.0 N after PEF treatment. 

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

2018 ◽  
Vol 237 ◽  
pp. 110-117 ◽  
Author(s):  
R. Ostermeier ◽  
P. Giersemehl ◽  
C. Siemer ◽  
S. Töpfl ◽  
H. Jäger
Keyword(s):  
Electric Field ◽  
Pulsed Electric Field ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Pre Treatment ◽  
Kinetics Of

scholarly journals Effect of Solar Radiation on the Drying Parameters of Mint (Mentha Spicata L.) Dried in Natural Convective Solar Dryer

2020 ◽  
Author(s):  
SEBIHA REHMAN ◽  
SEEMIN RUBAB
Keyword(s):  
Weather Conditions ◽  
Quality Parameter ◽  
Drying Process ◽  
Kashmir Valley ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Mentha Spicata ◽  
Solar Dryer ◽  
Pre Treatment ◽  
Kinetics Of

Abstract The paper presents a kinetic study of solar dried mint (Mentha spicata L.) without any pre-treatment. Mint grows effortlessly in Kashmir valley but is not obtainable throughout the year because of inconsiderate weather conditions. The genus belongs to the Labiatae family and includes large varieties with different properties. A significant quality parameter is its colour. The drying kinetics of mint leaves dried in Domestic Solar Dryer in terms of colour attributes, moisture content, drying time, non enzymatic browning, water activity, rehydration ratio was studied. This study is very useful for household scale drying of mint leaves to optimize drying process and to achieve superior quality dried product at home maintaining its colour and aroma.

scholarly journals Physicochemical Properties of Dried Apple Slices: Impact of Osmo-Dehydration, Sonication, and Drying Methods

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1078
Author(s):  
Joanna Cichowska-Bogusz ◽  
Adam Figiel ◽  
Angel Antonio Carbonell-Barrachina ◽  
Marta Pasławska ◽  
Dorota Witrowa-Rajchert
Keyword(s):  
Physicochemical Properties ◽  
Osmotic Dehydration ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Drying Time ◽  
Hygroscopic Properties ◽  
Fruit Samples ◽  
Apple Slices ◽  
Pre Treatment

Apple slices of the Elise variety were previously osmo-dehydrated in erythritol, xylitol, and sucrose for 2 h. In some parts of the experiment, 30 min of ultrasound pre-treatment (US) were applied. Afterwards, fruit samples were dried by convective (CD), microwave-vacuum (VM), and a combined method (CD/VM, mix two of them). The main aim of the research was to characterize an impact of osmotic dehydration, sonication pre-treatment, and drying method on the physicochemical properties of the dried apples. The use of sugar alcohols (xylitol, erythritol) in the production of dried apples did not badly affect the taste of the obtained dried products; it enabled a noticeable cooling/refreshing effect felt in the mouth when consuming a snack, and enabled the production of dried snacks with lower calorific value. Polyol residues in the product were at a level that was safe for consumers. The most popular convective drying was long lasting, whereas the VM drying method allowed for the shortest drying time, amounting to 76 min; moreover, additional application of ultrasounds reduced this time to 36 min. The combined drying method allowed the total duration of the process to be reduced 2–4.5 times. Ultrasound applied during osmotic dehydration did not significantly affect attributes of the descriptive sensory analysis for the obtained dried apples. The best hygroscopic properties, ensuring the storage stability of the dried product, showed dried apples previously osmo-dehydrated in erythritol and sucrose solutions.

scholarly journals BIOFUELS DRYING PROCESS EFFICIENCY RESEARCH / BIOKURO DŽIOVINIMO PROCESO EFEKTYVUMO TYRIMAI

2013 ◽  
Vol 5 (6) ◽  
pp. 609-614
Author(s):  
Osvaldas Šlepikas ◽  
Audrius Čereška
Keyword(s):  
Positive Impact ◽  
Ultrasonic Transducer ◽  
Process Efficiency ◽  
Convective Drying ◽  
Drying Process ◽  
Wood Pellets ◽  
Drying Time ◽  
Hot Air ◽  
Special Stand ◽  
Experimental Rig

The paper deals with biofuel drying process efficiency opportunities.Research was carried out with a special stand and performingexperiments. Experimental rig consists of an ultrasonic generator,ultrasonic transducer, a drying chamber and the humidity,temperature gauge. Tests were used for wood pellets. During theexperiment, they were irrigated with water, dried with hot air andadditionally exposed to different frequency ultrasonic vibrations.The tests results have showed that the convective drying processis combined with the ultrasonic vibrations, the drying time isreduced, which means a positive impact on the ultrasonic process.Studies have confirmed that the effectiveness of convectivedrying method combined with operating ultrasonic vibrationsincreases. Santrauka Straipsnyje nagrinėjamos biokuro džiovinimo proceso efektyvumo didinimo galimybės. Tyrimams atlikti sukurtas specialus stendas ir sudaryta eksperimento atlikimo metodika. Eksperimentinį stendą sudaro ultragarsinis generatorius, ultragarsinis keitiklis, džiovinimo kamera ir drėgmės, temperatūros matuokliai. Buvo tiriamos medžio granulės. Eksperimento metu jos buvo drėkinamos vandeniu, džiovinamos karštu oru ir papildomai veikiamos skirtingo dažnio ultragarsiniais virpesiais. Atlikus bandymus, rezultatai parodė, kad, veikiant konvekcinio džiovinimo procesą ultragarsiniais virpesiais, džiovinimo laikas sutrumpėja. Tai reiškia teigiamą ultragarso poveikį procesui. Tyrimais patvirtintas konvekcinio džiovinimo metodo efektyvumo, papildomai veikiant ultragarsiniais virpesiais, padidėjimas.

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.

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