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Nikolai I Lebovka

Nikolai I Lebovka
Biocolloidal Chemistry Institute named after F. D. Ovcharenko, National Academy of Sciences of Ukraine

Professor, Dr. Phys.-Math. Sci.

About

515
Publications
64,170
Reads
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10,529
Citations
Additional affiliations
September 2009 - present
National Taras Shevchenko University of Kyiv
Position
  • Professor
September 2001 - January 2012
National Aviation University
Position
  • Professor
January 1999 - present
Université de Technologie de Compiègne
Position
  • Invited professor

Publications

Publications (515)
Article
In the last two decades, pulsed electric fields (PEF) have successfully been introduced into the food industry, as one of the most promising and "game changing" technologies. This review is devoted to the recent applications of pulsed electric fields used in processing potatoes. The potato processing market size was estimated to be ca. USD 24.83 bi...
Article
Pulsed electric fields (PEFs) are becoming more and more popular in different applications in processing agricultural products. The PEF technology is based on the application of high voltage short pulses that allow electroporation in the cell membranes. This review outlines the PEF applications used in processing sugar beets. New perspective techno...
Book
This book addresses new challenges in soft matter and colloids. It presents timely reports on colloidal self-assembly, soft matters from liquid crystals, nanoparticles in liquid crystals, hydrocolloids, hybrid nanosystems, nanosuspensions, and dispersion of nanoparticles in different media, soft matter processing and modern experiments related with...
Chapter
The chapter presents a review on the history of the application of electricity in food processing. The early works before the middle of the twentieth century on the bactericidal and plasmolysis effects of electricity were shortly presented. Development of the concept of electroplasmolysis with a description of the activity of key persons (Anatolii...
Chapter
The chapter reviews applications of pulsed electric fields (PEF) for the efficient extraction of intercellular components from food plants. Mechanisms of cell membrane permeabilization by PEF including electroporation of plane membranes, spherical cells, cells with different shapes and sizes, and ensembles of cells and plant tissues are discussed....
Article
Relaxation of the packing of elongated particles (discorectangles) aligned on a line was studied numerically. The aspect ratio (length-to-width ratio) for the discorectangles was varied within the range ɛ∈[1;50]. The initial jamming (saturated) state was produced using the basic variant of the random sequential adsorption model with random position...
Article
The behavior of a system of two-dimensional elongated particles (discorectangles) packed in a slit between the two parallel walls was analyzed using a simulation approach. The packings were produced using the random sequential adsorption model with continuous positional and orientational degrees of freedom. The aspect ratio (length-to-width ratio,...
Article
Full-text available
Typically, the carrot tissues have rather high initial moisture content and low porosity. Expression of juice from such tissue may be rather complicated and include different stages. In this work, a simple creep tests with carrot tissue treated by pulsed electric fields (PEF) were performed. The samples were compressed for 15 min in a special jig u...
Preprint
Full-text available
Relaxation of the packing of elongated particles (discorectangles) aligned on a line was studied numerically. The aspect ratio (length-to-width ratio) for the discorectangles was varied within the range $\varepsilon \in [1;50]$. The initial jamming (saturated) state was produced using the basic variant of the random sequential adsorption (RSA) mode...
Article
Results of a comparative analysis of spectral-luminescent properties of crystalline and glassy benzophenone are presented. The main spectral characteristics (frequencies of purely electronic transitions in phosphorescence spectra, band half-widths, relative quantum yields) of glassy benzophenone have been found to possess a number of significant fe...
Presentation
Full-text available
Hybrid magnetic particles based on Laponite® (Lap) can be promising agents for ecology, therapeutics and diagnostic purposes. These materials combine unique magnetic and surface properties (e.g., high surface area, easily adjustable surface charge, relatively high adsorption capacity etc.). Due to its magnetic properties the external magnetic field...
Preprint
Full-text available
The behavior of a system of two-dimensional elongated particles (discorectangles) packed into a slit between two parallel walls was analyzed using a simulation approach. The packings were produced using the random sequential adsorption model with continuous positional and orientational degrees of freedom. The aspect ratio (length-to-width ratio, $\...
Presentation
Full-text available
Recent studies of the nanoparticle self-assembling in liquid crystals (LCs) are reviewed. The data on investigations of phase transitions, optico-luminescent, electrophysical and other functional properties are presented. The considered nanoparticles include surface-functionalized single-and multi-walled carbon nanotubes (CNTs) [1], Laponite  (Lap...
Article
Connectedness percolation phenomena in the two-dimensional packing of elongated particles (discorectangles) were studied numerically. The packings were produced using random sequential adsorption off-lattice models with preferential orientations of the particles along a given direction. The partial ordering was characterized by the order parameter...
Article
Dead-end electro-filtration of polyphenols extracted from apple skin was studied. The influence of membrane pore size (dm=3.02-50 nm), transmembrane pressure (ΔP=1-6 bar) and direct current (DC) electric field (U=5-15 V) on the purification efficiency was investigated. The sieving ratios R of selected membrane UH030 (dm=4.35 nm) towards the polyphe...
Article
The effects of pulsed electric field (PEF) treatment and preliminary vacuum drying (VD) on freezing assisted processes for the potato tissue were studied. The PEF treatment was done at 600 V/cm using the protocol to insure the high level of potato disintegration. The VD was done at sub-atmospheric pressure of p = 0.30 bar. Such conditions allowed r...
Chapter
Recent applications of pulsed electric energy (PEE) for the processing of food and agricultural products are reviewed in this chapter. The historical background and electroporation fundamentals for different food materials are presented. The chapter includes information about PEE treatment protocols, equipment, and chambers, and presents the main m...
Preprint
Full-text available
Connectedness percolation phenomena in two-dimensional packings of elongated particles (discorectangles) were studied numerically. The packings were produced using random sequential adsorption (RSA) off-lattice model with preferential orientations of particles along a given direction. The partial ordering was characterized by order parameter $S$, w...
Article
Full-text available
This work discusses the synthesis and the properties of magnetite modified LAPONITE® RD platelets (Lap). Magnetized Lap (mLap) nanoparticles were synthesized by a co-precipitation method with different weight ratios, X = Fe3O4/Lap (0–2). For characterization of the samples the particle size distributions and sedimentation behavior in an external ma...
Article
A computer simulation was used to study the random sequential adsorption of identical discorectangles onto a continuous plane. The problem was analyzed for a wide range of discorectangle aspect ratios ( ɛ ∈ [ 1 ; 100 ] ). We studied the anisotropic deposition, i.e., the orientations of the deposited particles were uniformly distributed within some...
Article
The random sequential adsorption (RSA) of identical elongated particles (discorectangles) on a line (“Paris car parking problem”) was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The possible orientations of the discorectanles were restricted between θ∈[−θm;θm] while the...
Preprint
Full-text available
Computer simulation was used to study the random sequential adsorption of identical discorectangles onto a continuous plane . The problem was analyzed for a wide range of discorectangle aspect ratios ($\varepsilon \in [1;100]$). We studied anisotropic deposition, i.e., the orientations of the deposited particles were uniformly distributed within so...
Preprint
Full-text available
The random sequential adsorption (RSA) of identical elongated particles (discorectangles) on a line ("Paris car parking problem") was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The possible orientations of the discorectanles were restricted between $\theta \in [-\theta_\...
Article
The aqueous suspensions of Laponite RD (Lap) platelets demonstrate rich phase diagrams. Both PEO and CTAB molecules competitively adsorb on the surface of Lap and strong interactions between PEO and CTAB exist. The stability of ternary systems Lap+PEO+CTAB can be finely regulated by changing the balance of these interactions. Electrokinetic techni...
Article
Aqueous extraction assisted by pulsed electric energy (PEE) and ultrasonication (US) were tested for three microalgal species (Nannochloropsis sp., Phaeodactylum tricornutum, Parachlorella kessleri). The PEE treatments were applied using pulsed electrical fields (PEF) and high voltage electrical discharges (HVED) modes. The extraction degrees of ca...
Article
In this study, the optimization of ultrasound‐assisted aqueous extraction of polyphenols from pomegranate peels and seeds was conducted. A 10‐min sonication (tu) pre‐treatment (≈60 W) accelerated the extraction kinetics and intensified the polyphenol recovery from peels and seeds. Ultrasound pre‐treatment permitted the selective recovery of polyphe...
Chapter
This chapter shortly presents the concepts of pulsed electric energy (PEE) generators, treatment protocols and design of batch and continuous treatment chambers (nano- and micro-scale fluidic chips, small-scale cuvettes, laboratory, pilot and industrial scale chambers). The manufacturers of small scale electroporation devices and large scale PEE eq...
Chapter
The grapes are cultivated all over the world and used as a fresh fruit and for the production of juice and wine. The grape berries are very rich in bioactive molecules such as carbohydrates, fruit acids, mineral elements, nitrogenous and aroma-producing compounds, vitamins, thiamine, riboflavin, anthocyanins responsible for the colour of red wine,...
Chapter
Detection and quantifying of electroporation effects in food and biological materials (food plants, biomass feedstocks and bio-suspensions) is very important for numerous practical applications. Currently, different methods and techniques have been proposed to detect and measure electroporation effects. This chapter presents the current methods to...
Chapter
Effects of electricity on biological objects attracted a great attention of researches over several centuries. Many interesting, intriguing, and unclear phenomena were discovered under application of electricity. The early works on the effects of electricity on germination, vegetation, plants growth, medical applications, and killing of bacteria we...
Chapter
Drying is widely used for the dehydration of food plants (fruits, vegetables) and biomass feedstocks. Efficiency of drying depends on the processing conditions, structure of the material (size and orientation of cells, their integrity), and types of cellular water in the samples. Efficiency of the traditional convective air drying is rather low, th...
Chapter
Cell membrane electroporation phenomena depend on the size of cells, their spatial orientation, electro-physical parameters of cells, pH of surrounding media and presence of osmotic agents. This chapter discusses fundamentals of membrane electroporation, various non-pore and pore models (condenser and conductor approximations), stages of electropor...
Chapter
Freezing at subzero temperatures is widely used to preserve quality of food products and obtain minimal deterioration of original colour, flavour, texture and other organoleptic and nutritional properties of foods. Existing freezing preservation technique goals to avoid formation of large ice crystals inside the foods by control the heat removal. T...
Chapter
Among conventional extraction techniques in food and biorefinery applications, solvent extraction (named leaching, diffusion) and expression (pressing) are the most important. Solid/liquid extraction and expression are widely used for the production of fruit juices, wines, sugar, vegetable oils and starch, as well as for the extraction of different...
Chapter
The “fruit” means the fleshy seed-associated structures of a plant that are sweet or sour, and edible in the raw state. The systems for classifying of fruits are related to food composition and based on botanic families, colours, and edible parts of plants. This chapter discusses examples of application of the PEE for processing of three types of f...
Chapter
Sugar crops include sugar beet, sugarcane, sweet sorghum, sugar maple, sugar palm, honey, corn, and chicory. Sugar is a broad term applied to a large number of carbohydrates that have a more or less sweet taste. Sugar crops are the basic feed stocks in the traditional converting technologies producing sugar, inulin and other food ingredients. The r...
Chapter
Potato and carrot are important sources of energy (starch), high-quality proteins, fibers, and vitamins. This chapter considers examples of PEE application for the processing of potato and carrot crops. For potato, the applications of PEF for French fries manufacturing, improving of drying and extraction processes and treatment of peel wastes are p...
Chapter
Biomass usually refers to the nonfood part of plants, by-products and wastes. Various biomass resources include wood wastes, grass and herbaceous crops, agricultural and industrial residues like bagasse, sugar beet pulp and molasses, oilseed residues, municipal solid wastes, aquatic plants, microalgae, animal wastes, etc. Dedicated feedstocks are t...
Book
This book presents a comprehensive range of research on pulsed electric energy used in food processing, including sections on the fundamentals of electroporation and important techniques for the estimation of electroporation effects in various foods and biomass feedstocks. By focusing on application over theory, this book presents researchers with...
Article
Two-step procedure with the initial aqueous extraction from raw microalgae Nannochloropsis oculata and secondary organic solvent extraction from vacuum dried (VD) microalgae were applied for selective recovery of bio-molecules. The effects of preliminary aqueous washing and high voltage electrical discharges (HVED, 40 kV/cm, 4 ms pulses) were teste...
Article
The effects of physical treatments (pulsed electrical fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US)) on aqueous extraction of carbohydrates and proteins, and ethanolic extraction of chlorophyll a from three microalgal species (Nannochloropsis sp., P. tricornutum and P. kessleri) have been studied. The total energy...
Article
The pulsed electric field (PEF) assisted extraction of bio-compounds (soluble solids concentration, oBrix, and total polyphenol content, TPC) from apple peels was studied. The aqueous suspensions of apple peels were treated by PEF with different intensities, E (480-1200 V/cm), and different treatment times, tPEF (0-2 s). The cell disintegration was...
Article
A multi-step aqueous and non-aqueous extraction procedure was applied to recovery bio-molecules from Phaeodactylum tricornutum. The process include that physical pre-treatments (high voltage electrical discharges (HVED, 40 kV/cm, 1–8 ms, HVED samples) or high pressure homogenization (HPH, 1200 bar, 10 passes, P samples)) (1st step); aqueous extract...
Article
Background Nowadays, electron spin resonance (ESR) is widely used as a powerful, non-destructive and very sensitive technique for the detection of free radicals in food systems. It can be applied for the direct identification of highly reactive oxygen species, organic and inorganic paramagnetic species and screening of food for potential toxicity....
Chapter
Farming and production of food are one of the oldest industries in the human history. Among other issues, food processing is an important part in the whole food industry. It includes the methods and techniques used to transform raw material into food for human consumption. Most of these techniques are well known and their principals have not been c...
Preprint
Full-text available
To be published as a chapter of Order, Disorder and Criticality. Advanced Problems of Phase Transition Theory, Volume 6. Edited By: Yurij Holovatch (National Academy of Sciences, Ukraine) WORLD SCIENTIFIC, 2020. ISBN: 978-981-121-621-3 (hardcover) This chapter is devoted to the analysis of jamming and percolation behavior of two-dimensional system...
Article
The effects of preliminary vacuum drying (VD) and pulsed electric field (PEF) treatment on characteristics of fried potatoes were studied. The samples were preliminary dehydrated to a different levels (with moisture ratio of MR ≥ 0.2) using VD at sub-atmospheric pressure of p = 30 kPa, and two different drying temperatures, Tv = 40 °C and 70 °C. Af...
Article
Relaxation in a two-dimensional suspensions containing rods was studied by using dynamic Monte Carlo simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state was produced by using a random sequential adsorption model. During the relaxation, the rods underwent translational a...
Chapter
The structure and properties of soft colloidal systems filled by nano-disks of Laponite® (Lap) are critically reviewed. The known Lap grades, chemical structure and physical properties are described. Various phases formed by exfoliated surface-charged Lap discs in aqueous media are analyzed, accounting for the kinetics of phase transformations and...
Article
The organic substance quercetin, when added to liquid crystal (LC) systems as non-mesogenic dopant significantly affects properties of the LC host. The microphotographs of cholesteric (M5) and nematic (5CB) LC textures evidenced about presence of aggregation quercetin molecules in LC hosts. These results are in agreement with literature data on que...
Article
The effects of aqueous extraction of bioactive compounds from pomegranate peels using conventional extraction (CE) and extraction assisted by infrared irradiation (IR), ultrasound (US), pulsed electric fields (PEF), and high-voltage electrical discharges (HVED) have been compared. For the extractions assisted by US, PEF and HVED, the saturation in...
Preprint
Full-text available
Aging in a two dimensional suspension containing rods was studied by means of kinetic Monte Carlo simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state was produced using a random sequential adsorption model. During the aging, the rods underwent translational and rotation...
Conference Paper
Full-text available
Laponite(Lap) is synthetic clay with platelet particles (a thickness of 1 nm and a diameter of 25 nm) with wide applications in chemical engineering, medicine and cosmetics. An important feature of Lap particles is ability to induce the formation of "empty liquid" structures. The evolution of fresh suspensions of Lap from liquid to gel-like state...
Article
The disintegration efficiencies of microalgal Parachlorella kessleri cells by ultrasonication (US) and high pressure homogenization (HPH) treatments were investigated. The applied procedures included individual US, individual HPH, or combined US followed by HPH treatments. The test concentrations of cell suspensions were 1% and 10% dry matter. The...
Article
Full-text available
The sedimentation of a two-dimensional suspension containing rods was studied by means of Monte Carlo (MC) simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state before sedimentation was produced using a model of random sequential adsorption. During such sedimentation, the...
Article
The effects of Brownian motions on the electrical conductivity and optical transparency of two-dimensional films filled with needle-like particles (needles) have been investigated, using the Monte-Carlo method. The initial state of the system was produced with the use of the random-sequential adsorption process. In the subsequent evolution (aging)...
Conference Paper
Full-text available
By means of computer simulation, we examined the effect of dispersity of filler length on electrical conductivity of two-dimensional (2D) composites with rod-like fillers. A continuous approach was used. Highly conductive zero-width rod-like particles were deposited uniformly with given anisotropy onto a poorly conductive substrate. Length of parti...
Article
The ultrasound (US) assisted purification of polyphenols of apple skins by adsorption/desorption on the poly-aromatic Amberlite adsorbent XAD-16 was studied. The adsorption steps were done at different temperatures (T = 25–40 °C) with application of US at different intensities (P = 0–400 W). The desorption steps were tested in aqueous ethanol solut...
Article
Full-text available
Microalgae of Nannochloropsis sp. present valuable source of bio-molecules (pigments, lipids, proteins) that have nutritional potential for the prevention and treatment of human diseases. Moreover, some species of Nannochloropsis are the promising sources of biofuels and excellent candidates for the replacement of classical biofuel crops. This revi...
Preprint
Full-text available
The sedimentation of a two dimensional suspension containing rods was studied by means of kinetic Monte Carlo (MC) simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state before sedimentation was produced using a model of random sequential adsorption. During such sedimentat...
Chapter
The different nonthermal emerging technologies assisted by pulsed electric fields (PEFs) are effective for the selective extraction of valuable constituents from food plants and biosuspensions, and for the preservation of food products. This chapter describes the mechanism of PEF treatment, effects of PEF parameters on cell membranes and cell tissu...
Article
The ultrasound (US) assisted extraction of bio-compounds from different fruit skins (apples, bananas and persimmons) was studied. The aqueous suspensions of skins were treated by US with different energy inputs (0.033–0.299 kW·h/kg) and total time of aqueous extraction was up to 2700 s. The ionic, Zi, and total polyphenol, Zp, extraction indexes of...
Article
The results of systematic study of the impact of electrolytes (in a wide range of electrolyte concentration, C = 10⁻⁵–10⁻¹ M) with alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) containing chlorides and sulphate anions on electrosurface properties of aqueous suspensions containing hydrophobic (polystyrene latex with surface sulphate or carboxylic group...
Article
The effects of pulsed electric field (PEF) treatment on drying of potato have been investigated. The convective air (CA) (T = 50 °C), microwave (MW), and combined (CA + MW or MW + CA) drying was applied. The drying curves, progression of temperature inside samples, microstructure, and capillary imbibition capacity of untreated (U) and PEF treated s...
Article
Using Monte Carlo simulation, we studied the electrical conductivity of two-dimensional films. The films consisted of a poorly conductive host matrix and highly conductive rod-like fillers (rods). The rods were of various lengths fitting a log-normal distribution. They could be aligned along a direction. Special attention was paid to films having c...
Article
Monte Carlo model for simulation of light transmission in anisotropic suspensions filled by absorbing cylindrical particles with anisotropic shape was developed. Aspect ratio of the cylinders (i.e., ratio of length and diameter) was varied between r = 0 (infinitely thin disks) and r → ∞ (infinitely thin rods). The cooperative filling model was used...
Preprint
Full-text available
By means of computer simulation, we examined effect of dispersity of filler length on electrical conductivity of two-dimensional (2D) composites with rod-like fillers. Continuous approach has been used. Highly conductive zero-width rod-like particles were deposited uniformly with given anisotropy onto a poorly conductive substrate. Length of partic...
Article
Full-text available
The extraction of soluble matter (°Brix), catechin and total phenolic compounds (TPC) from apple flesh was studied. A conventional aqueous extraction (CE) was done at different temperatures (50, 60, and 75 °C). A pulsed ultrasound-assisted extraction (UAE) was done at fixed temperature, T = 50 °C, and different specific energy input and total durat...
Preprint
Full-text available
Using Monte Carlo simulation, we studied the electrical conductivity of two-dimensional films. The films consisted of a poorly conductive host matrix and highly conductive rod-like fillers (rods). The rods were of various lengths fitting a log-normal distribution. They could be aligned along a direction. Special attention was paid to films having c...
Article
Numerical simulations by means of the Monte Carlo method have been performed to study the electrical properties of a two-dimensional composite filled with rodlike particles. The main goal was to study the effect of the alignment of such rods on the anisotropy of its electrical conductivity. A continuous model was used. In this model, the rods have...
Article
Ultrasound-assisted aqueous extraction (UAE) of soluble matter (°Brix), catechin and total phenolic contents (TPC) from flesh and peel of apple tissues were studied. The commercial green (Granny Smith) and red (Red delicious) apples were used in the investigation. All extractions were done at fixed temperature, T = 50 °C, and protocols with differe...
Article
Effects of pulsed electric fields (PEF) on vacuum drying of potato tissue were studied. PEF treatment was done using electric field strength of E = 600 V/cm and total treatment time of tPEF = 0.1 s to reach a high level of potato tissue disintegration. The vacuum drying was performed at sub-atmospheric pressure, p = 30 kPa (that corresponds to the...