INTRODUCTION
Economical and environmentally friendly methods
of food processing require novel technological solutions
to maintain the high quality of finished products [1–3].
Food science helps understand the impact of innovative
approaches on the properties of substances in the
production chain, from raw materials and by-products to
finished products and waste disposal issues [4–6].
The structure and properties of food ingredients
depend on such physical conditions as temperature,
pressure, stirring speed, etc., as well as on chemical
interactions with other nutrients, e.g. water [7–9].
A targeted effect on the water base can develop the
desired characteristics of the semi-finished or finished
product [10, 11]. The food industry uses electrochemical
activation as a relevant method of reagent-free control of
physicochemical and rheological properties.
Electrochemical activation, or electrolysis, is
a unipolar electrochemical processing of water or
aqueous electrolyte solutions. It occurs in the anode
or cathode chamber of a diaphragm or membrane
electrochemical reactor [12, 13]. Electrolysis happens
as a result of electrochemical and electrical processes
in water in a double electric layer of electrodes
with a non-equilibrium electric charge transfer.
Water is treated with a constant electric current,
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and electric potentials exceed its decomposition
voltage (+1.25 V). As a result, water passes into
a metastable state with non-standard electron
activity, redox potential, and other physicochemical
parameters. Electrochemically activated water is
able to retain this metastable state for a long time
and resists the thermodynamic equilibrium with the
environment [12].
Metastable compounds with a high oxidizing
(anolyte) or reducing (catholyte) ability undergo
a series of spontaneous structural, energetic, and
chemical transformations and gradually stabilize
during storage. They are highly reactive to chemicals
and biological objects. Metastable compounds enhance
acidic and oxidizing properties of anolyte, as well as
the alkaline and reducing properties of catholyte [14–
17]. Electrochemical nonequilibrium leads to multiple
changes in the reactivity of ions but does not affect their
concentration. In electrochemically activated water, the
pH values of catholyte and anolyte correspond to the
equilibrium concentrations of alkali and acid that exceed
the content of salts in this water. The redox values also
go beyond the chemical control capabilities for a given
electrical conductivity [12].
Electrochemically activated water and its solutions
owe their chemical activity to electrically active
microbubbles of electrolysis gases. These microbubbles
are 0.2–5.0 μm in size, and their concentration can reach
106–107 mL−1. They are stabilized by uncompensated
electric charges at the interface of gas and liquid phases
[12, 14, 18].
Electrochemically activated water and its solutions
have non-standard physicochemical parameters of pH
and redox potential, which makes them biologically
active [13, 18, 19]. Electrochemically activated water
solutions of both low and high molecular weight
compounds differ from similar solutions of nonelectrolyzed
water [12, 16].
Electrochemically activated water and its solutions
behave differently in technological processes. For
instance, electrochemically activated water and
ultrapure water are known to affect apricot protein
extraction [20]. At the same pH = 9.5, electrochemically
activated water had a better extraction efficiency
than ultrapure water. Foaming ability and stability
of the electrochemically activated water emulsions
were 11.17% and 36.33 min, whereas in the ultrapure
water samples they were 4.75% and 23.88 min,
respectively. Electrochemically activated water had
a more ordered secondary structure than ultrapure
water. The ordered structures of α-helix and β-sheet
were 7.5 and 60.2%, while the disordered structures
and random turns were 8.4 and 23.8%, respectively.
The extraction method increased the yield of the
product, minimized the structural degradation,
and improved the functional properties of apricot
protein [20].
Electrochemical activation proved an effective
means of extracting protein from canola meal [21].
Under the electric field, the cathode chamber produced
an alkaline solution from a sodium chloride (NaCl)
solution. The alkaline solution had better extractive
properties compared to the samples subjected to
chemical alkalization. The extracted proteins had
a better extractability, composition, and secondary
structure. The concentration of NaCl was 0.01–1 M,
electroactivation time – 10–60 min, current – 0.2 and
0.3A. The experiment was conducted in a three-chamber
cell separated by ion-exchange membranes.
The resulting solutions underwent an extraction
procedure. The maximal protein extract of 34.32 ± 1.21%
occurred when the electrolyzed solution was generated
at 0.3A, regardless of the activation time. The
standard extraction (pH 7–10) yielded 31.18 ± 1.89%
proteins under the same conditions. The Sodium
Dodecyl Sulphate Polyacrylamide Gel Electrophoresis
(SDS-PAGE) showed that the electrophoretic profiles
of electrolyzed protein concentrates and isolates
differed from those obtained with the conventional
method. The Fourier Transform Infrared Spectroscopy
(FTIR) showed significant differences in the secondary
structures of proteins depending on the pH and salt
concentration. The electrochemically activated samples
had a lower denaturation [21].
Electric field can change the properties of aqueous
protein solutions due to their electrical conductivity
and the chemical structure of polyampholytic
polyelectrolytes. Their amino acid units have ionogenic
side groups, and their acidic groups alternate with
basic ones, which provides macromolecules with
specific electric, configuration, and hydrodynamic
properties [22]. Molecular conformation, volume,
and rheology depend on the concentration of the
polyelectrolyte in the solution, e.g. temperature,
pressure, low molecular weight substances,
pH value, etc. [23–27].
Animal blood proteins can serve as an example
of such relationships. Serum proteins have a lot of
beneficial nutritional properties, which makes them
part of many food formulations. A globular molecule
of bovine serum albumin consists of several hundred
amino acid residues. Its three-dimensional structure is
labile, mobile, and sensitive to exogenous factors [23, 26,
28]. A bovine serum albumin solution contains protein
fragments of different dimensions. Its monomers and
aggregates are in a state of dynamic equilibrium, and
the weight of polypeptides increases as the albumin
concentration in the solution rises [26].
The dissolution of crystalline albumin depends
on the contact time of the phases: it can change its
conformation, develop intermolecular bonds, or destroy
them. The structure of albumin solutions and their
surface properties depend on the pH of the solution and
the pH value of the isoelectric point. The closer to the
isoelectric point, the more turbid the solutions are and
the lower their viscosity gets. This phenomenon can
be explained by the minimal energy of electrostatic
repulsion between the side chains of albumin molecules
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and the molecules themselves. The resulting aggregates
are denser, more compact, and larger in size. They have
less effect on the flow and increase light scattering.
During structuring, the turbidity and viscosity of the
solutions change nonlinearly, depending on the protein
concentration [24, 27].
The surface activity of albumin increases together
with proton concentration. In an acidic environment,
more non-polar groups emerge on the surface of
the molecule than in a neutral or slightly alkaline
environment. Obviously, the surface activity of albumin
molecules is minimal at physiological pH values [27].
Denaturation and aggregation of serum protein
isolates depend on the pH of the medium. This effect
is widely used in food technology. When acidity pH
drops to 1, it leads to the denaturation of bovine serum
albumin with a conformational transition. This process
is caused by the loss of the tertiary structure, which
occurs as the polypeptide chain of the bovine serum
albumin molecule unfolds and the aggregates increase in
size [26].
A strong alkaline environment has a more
pronounced texturing effect, e.g. 2N NaOH solution with
a pH of 12.4 ± 0.4 or alkaline electrolyzed water with a
pH of 11.5 ± 0.4. In an acidic environment, the effect is
less pronounced, e.g. 2N HCl with a pH of 2.0 ± 0.2 or
acidic electrolysis water with pH 2.5 ± 0.2 [29]. Albumin
is a polyelectrolyte with a high conformational mobility.
In an electrochemically activated solution, it should be
sensitive both to the acidity of the solution and its redox
potential. The present research objective was to study
the effect of electrochemically activated water on the
properties of serum albumin in protein solutions.
STUDY OBJECTS AND METHODS
Sample preparation. The research featured bovine
serum albumin BSA 100 (Merck, Sigma-Aldrich).
Preparations with casein proteins and instant food
gelatin were used as control (Dr. Oetker, OOO Oetker,
Russia, TU 20.59.60-011-42450906-2018).
The research involved UV spectrometry, time-offlight
secondary ion mass spectrometry (ToF-SIMS),
and electrophoresis of an 1% protein aqueous solution,
which was then diluted with water or electrochemically
activated water at a ratio of 1:4. Fractions of electrolyzed
water, catholyte (pH 8.2, redox –800 mV), and
anolyte (pH 2.2, redox +800 mV) were obtained in
a fresh drinking water purification unit by means of
direct electrochemical action in diaphragm modular
electrochemical cells (LLC Delfin Aqua, Russia).
Artesian water (pH 7.2, redox +360 mV) from the city
water supply served as control. In the viscosity test,
electrolyzed water with a negative redox value was
obtained using an Izumrud-K1 installation (NPO Ekran
OJSC, Russia). Tap water passed through a number of
stages:
1. Anode chamber of a flow-type electrochemical
module. Here the water was disinfected due to peroxide
and chlorine-oxygen compounds, then saturated with
oxygen and ozone to kill microorganisms and oxidize
organic impurities;
2. Reaction-flotation reactor. It removed coagulated
products of anodic treatment from electrolytically
obtained microbubbles of oxygen and ozone;
3. Heterophase catalytic reactor. The procedure
removed active chlorine compounds and produced active
oxygen compounds;
4. Cathode chamber. Here the residual ions of iron,
copper, magnesium, etc. were converted into insoluble
hydroxides, which were then removed in the flotation
and electrokinetic reactors. During the cathodic
treatment, molecular hydrogen and free hydroxyl groups
entered the water and gave it a negative redox value and
antioxidant properties.
The electrochemically activated water had pH 7.3
and redox –223 mV, while for the initial water these
values were 7.3 and +190 mV, respectively. The acidity
(pH) and redox potential of the solution were measured
using a SevenExellence S470 multivariable device
(METTLER TOLEDO, Switzerland) with a pH electrode
(Inlab Routine Pro, Mettler Toledo, Switzerland) and
a redox electrode (Inlab Redox Pro, Mettler Toledo,
Switzerland). Depending on the concentration of
bovine serum albumin, its pH value ranged 7.2–7.6 for
electrolyzed water and 7.9–8.6 for tap water.
UV spectrometry. Spectrometry was used to
define the effect of electrolyzed water on aqueous
protein solutions. Its optical density was recorded in
the absorption spectrum of the sample in the ultraviolet
region at a wavelength of 235 and 280 nm using a
Shimadzu UV-2401PC spectrophotometer (Japan).
Time-of-flight secondary ion mass spectrometry
(ToF-SIMS). To obtain samples for mass spectrometry,
2 μL of bovine serum albumin solution in water or water
fractions were applied to a clean glass substrate. Its
surface was covered with a conductive ITO-indium tin
oxide film (Sigma-Aldrich). After drying in an stream,
the sample was transferred to the chamber of a ToFSIMS
5 secondary ion mass spectrometer (ION-ToF
GmbH, Germany). The preparation was ionized with a
200 nm beam of primary Bi3+ ions at 30 keV. After 70 ns
of exposure, secondary ions were registered (~ 80 μs)
and the beam moved to the next point. The primary
ion irradiation did not exceed 5 × 1012 ions/cm2. The
principal component analysis helped to assess the
differences between the obtained mass spectra [30, 31].
Measuring the kinematic viscosity of protein
solutions. This parameter was measured using an
Ostwald VPZh-4m capillary viscometer (VPZh-4m
viscometer, LABTECH LLC, Russia) at 20°C. The
viscosity value was calculated as follows:
( * * )
9,8
g K t
V = (1)
where V is the kinematic viscosity of the liquid, mm2/s;
K is the constant of the viscometer, mm2/s2; t is the flow
time, sec; g is the gravity acceleration, 9.8 m/s2.
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The protein content in the diluted solution was 0.01,
0.05, 0.1, and 0.2%; in the concentrated solution – 1, 3, 5,
and 10%.
Protein electrophoresis. This parameter was
measured using standard methods and the following
ingredients. Acrylamide 8% separating gel contained
0.375 M Tris HCl (pH 8.8), 0.1% PSA (ammonium
persulfate 0, 0.1% DS-Na (Dodecylsulfat Na-salz),
and 0.01% TEMED (tetramethylethylenediamine).
Acrylamide 5% focusing gel included 0.125 M Tris HCl
(pH 6.8), 0.1% PSA, 0.1% DS-Na, and 0.01% TEMED.
The electrode buffer included 0.025 M Tris HCl (pH 8.3)
and 0.19 M glycine.
The protein was diluted in buffer: 2% DS-Na, 10%
glycerin, 5% 2-mercaptoethanol, 0.004% bromophenol
blue, 0.063 M Tris HCl, pH 6.8. After that, it was boiled
in a 100% water bath for 5 min. The solution was
applied to the gel, where electrophoresis was carried out
at 20 mA for 2 h. The resulting preparation was stained
with Cumassi R 250.
RESULTS AND DISCUSSION
UV spectrometry. The method of UV spectrometry
of aqueous solutions was used to study the effect of
electrochemically activated water on protein. The UV
spectrum was not specific for biomolecule solutions, but
it made it possible to perform a comparative analysis of
integral changes in the sample. The UV spectrometry
test featured bovine serum albumin, food gelatin, and
casein (Fig. 1).
Figure 1 demonstrates that the obtained absorption
spectra were identical for all the proteins in the
experiment. Unlike the conventional water solutions,
the solutions of electrochemically activated water
fractions had a lower optical density, and their
absorption peak was in 235–280 nm. All the samples of
electrochemically activated water had a slightly higher
absorption level of the protein solution in catholyte.
These changes were more obvious in the solution of
biochemically pure albumin (Fig. 1a) than in the samples
of food gelatin (Fig. 1b) and casein (Fig. 1c). The UV
spectrometry demonstrated the modification of the
protein in the solution of electrolyzed water fractions.
The time-of-flight molecular mass spectrometry (ToFSIMS)
provided additional data on the state of albumin
in the solutions.
Time-of-flight secondary ion mass spectrometr
(ToF-SIMS). This method was used to perform the
molecular analysis of protein samples. A droplet of
each solution was dried on a cover glass in a stream
of clean air. ToF-SIMS provided information about
chemical composition, molecular orientation, surface
order, chemical bonding, and purity. Mass spectra of
each preparation were compared using various data
classification techniques. The principal component
analysis is one of the most popular techniques used
in mass spectrometry. It features the most intense
peaks in mass spectra and provides a 95% confidence
interval [30, 31].
Briefly, the program received 20 principal
components: the higher the component number, the
more variation in the data it reflected. Such a number
of coordinates was unnecessary, so the space of
the first two components was used to analyze the
similarity of the samples. All the samples of biological
macromolecules in this research underwent the same
ToF-SIMS preparation procedure and the same principal
component analysis. Figure 2 shows the results of the
molecular mass spectrometry.
Figure 2a illustrates a typical mass spectrum of
bovine serum albumin dissolved in water or electrolyzed
water fractions. Figure 2b clearly demonstrates a
significant difference between all three samples.
The catholyte-treated protein showed significant
heterogeneity compared to the control and especially
the anolyte-treated sample. Anolyte treatment had a
focusing effect on the protein samples, if compared to
the heterogeneous group of samples obtained from the
albumin solution in catholyte or water. The change in the
mass spectrum may be due to the development of new
Figure 1 Nonspecific UV absorption spectra of 0.20% solutions of bovine serum albumin (a), food gelatin (b),
and casein (c) in water or electrochemically activated water fractions (catholyte, anolyte)
water
catholyte
anolyte
water
catholyte
anolyte
water
catholyte
anolyte
a b с
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peaks and/or a change in the intensity of similar peaks.
The results of molecular analysis statistically confirmed
the UV spectrometry data (Fig. 1a): electrochemically
activated water fractions really modified the albumin.
The total change in the physicochemical properties
of protein could change in the rheological properties
(viscosity) of the solution.
Kinematic viscosity of bovine serum albumin.
The viscosity of aqueous solutions of hydrocolloids
is an important characteristic of food systems. For
instance, the viscosity of protein solutions is one of
the most serious problems when highly concentrated
protein formulations or milk powder. The viscosity of
food systems is controlled both by physical methods
and by additives. A small amount of such low molecular
weight additives as salt reduces the viscosity that results
from electrostatic repulsion and attraction. Arginine
hydrochloride (ArgHCl) is known to act as a chaotropic
agent. It destroys the network of hydrogen bonds
between water molecules, thus suppressing hydrophobic
Figure 2 ToF-SIMS analysis of bovine serum albumin samples in conventional water (control) and electrochemically activated
fractions (anolyte, catholyte): (a) ranges of molecular weights: bottom mass spectrum – control (water), medium – after catholyte
treatment, upper – after anolyte treatment; (b) ellipses – 95% confidence areas for n = 6 measurements for each group
water
catholyte
anolyte
catholyte
anolyte
water
а
b
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attraction and clustering, which can reduce the viscosity
of the solution [32].
Hydrodynamic cavitation served as a technological
tool to reduce the viscosity of serum protein concentrate
before spray drying. Whey protein concentrate
(31% dry matter) underwent various hydrodynamic
cavitation treatments. The samples were tested for
viscosity during 14 days of storage. The enthalpy of
denaturation was estimated using differential scanning
calorimetry, while the particle size was measured
using dynamic light scattering. The hydrodynamic
cavitation treatment appeared to reduce the viscosity by
7–8%, and this effect remained constant for 14 days of
storage. According to the particle size distribution, the
destruction of aggregates decreased the number of large
particles and thus caused the drop in viscosity [33].
The viscosity of protein solution depends not only
on the size, but also on the shape, morphology, and
structure of the particles. For instance, flow behavior
of partially denatured serum protein aggregates
showed a complex dependence on the microstructural
morphology of particles, their concentration, and
shear rate [24]. Even though the protein content in the
solution was the same, particles with an open fibrillar/
tubular structure had a higher viscosity than compact
aggregates. Rough and uneven particles appeared to
form solutions of higher viscosity than smooth particles
of the same size. Serum proteins of various sizes and
denaturation degrees produced solutions of different
viscosity, probably, as a result of interactions between
protein aggregates. Partial denaturation technology
could control the structure of serum protein aggregates
to achieve specific viscosity characteristics [24].
Protein is a biopolymer. Hence, the viscosity of
its solution depends not only on its properties and
concentration, but also on the solvent. Temperature,
pH, impurities, and dissolved gases affect the viscosity
of solutions. For example, negative redox potential can
affect the quality and interaction efficiency of dissolved
macromolecules [34, 35].
This part of the experiment featured electrolyzed
water with a standard acidity value (pH ~ 7.3) but
extremely low redox potential (–223 mV) at the starting
point. The redox potential value of tap water in the
control sample remained constant (+190 mV) at 20°C
during 24 h. However, the redox potential value of
electrolyzed water (–223 mV) gradually increased as
the metastable state relaxed. The highest relaxation rate
occurred in the first 6 h after treatment, and then the
process slowed down. After 24 h, the redox potential
reached +69 mV, which was much lower than in the
control sample. As the concentration of albumin kept
growing from 0.01 to 0.2%, the relaxation rate increased
gradually. After bovine serum albumin dissolved, the
redox potential index increased from –194 to –162 mV.
When the albumin concentration reached 1–3%, the
effect intensified abruptly and reached plateau at
–90 mV. Adding bovine serum albumin speeded up
the recovery of the redox potential of the electrolyzed
water. The kinetics of the process depended on the
concentration. After 24 h, the maximal value was
+125 mV at 0.2% of bovine serum albumin, which
was much lower than the redox potential of the control
sample (+190 mV).
The results clearly showed the dependence of the
redox potential of electrochemically activated water
solutions on albumin concentration. Such interactions
may affect the kinematic viscosity of the solution: the
molecular conformation change and/or intermolecular
bonds are distorted. The structure of water in the
electrochemical reactor changes, thus resulting in a
negative redox potential of the water. These changes
can also affect the behavior of macromolecules, i.e.
solubility, interaction, conformation, repulsion or
attraction, as hydrogen, hydrophobic, or electrostatic
non-covalent bonds get stronger or weaker [36, 37].
Figure 3 shows the changes in the kinematic
viscosity of the solutions of tap water and electrolyzed
water at different concentrations of bovine serum
albumin from 1 to 10%.
Electrochemical treatment of tap water decreased
the viscosity of the solution at all the concentrations of
bovine serum albumin (Fig. 3). The tap water solution
became more viscous over time, while the electrolyzed
water with the same concentration of albumin remained
almost the same. The viscosity of the solution usually
Figure 3 Kinematic viscosity of water solution
vs. electrochemically activated water solution
at different concentrations of bovine serum albumin, %
Kinematic viscosity, mm2/s
Storage time, h
Electrolyzed water solution
Electrolyzed water solution
Electrolyzed water solution Electrolyzed water solution
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increases together with the increase in the protein
content, but electrolyzed water reduced the initial value
of this parameter, especially in the 10% solutions of
bovine serum albumin. This effect might have resulted
from the increased electrostatic repulsion between
albumin molecules. At an isoelectric point of pl 4.9
and pH 7.3–8.6, the total charge of the protein became
negative due to additional dissociation of carboxyl
groups caused by albumin molecular conformation.
Both the protein monoproduct sample (albumin)
and the food protein composition samples (gelatin and
casein) changed when dissolved in the electrolyzed
water fractions. The observed effects might be a
consequence of changes in the structure of the protein
and/or its fragmentation. Figure 4 shows the results of
gel electrophoresis.
Protein electrophoreses differed (Fig. 4), but the
solutions of the same protein in water or electrolyzed
water fractions showed no significant differences.
A high performance liquid chromatography
(HPLC) confirmed this observation. The data of gel
electrophoresis differed from the results of molecular
analysis (ToF-SIMS) because these two methods are
based on different physical principles. Electrophoresis
features proteins and their large fragments in an electric
field while mass spectrometry registers amino acid ions
and small peptides. The decrease in molecular weight
under the action of electrolyzed water was insignificant,
but it could still affect the peptide structure both in the
oxidized (pH 2.2, redox +800 mV) and reduced (pH 8.2,
redox –800 mV) fractions of electrolyzed water. When
proteins dissolved in the anodic and cathodic fractions of
purified drinking water, they got neither fragmented nor
structurally changed.
The effect of the anodic and cathodic fractions
of electrolyzed water on the properties of serum
albumin confirmed the prospects of the targeted use
of electrochemical activation in the food industry as a
means of condition monitoring.
The research results correlated with other studies
that state the importance of water for reagent-free
control of protein quality in the food industry. According
to [38], polyphosphate (50%) can be partially replaced
with alkaline electrolyzed water (1.25 g/L sodium
tripolyphosphate, 0.3 g/L sodium metapolyphosphate,
0.4 g/L sodium polyphosphate, pH = 11.4). The
replacement improved the quality of catfish fillet: its
weight and water retention capacity increased. A higher
phosphate content had a similar result (2.5 g/L sodium
tripolyphosphate, 0.6 g/L sodium metapolyphosphate,
0.8 g/L sodium polyphosphate, pH = 9.0). However,
the experiment established no change in hardness
and elasticity. The test samples improved in color and
oxidation resistance, though [38].
Electrochemical activation proved to be an effective
sustainable technology to produce acidic and alkaline
(anolyte and catholyte) extraction solutions that could
replace hydrochloric acid and sodium hydroxide.
For example, a combination of electrolyzed water
and ultrasonic treatment improved the efficiency
of extracting proteins from sea krill [39]. Unlike a
similar combined method with deionized water, the
electrolyzed water method reduced NaOH consumption
by 30.9% w/w. Electrochemically activated water with
a negative redox potential –(800–900 mV) showed
good antioxidant properties, which protected the active
groups of proteins (carbonyl, sulfhydryl) from oxidation.
Ultrasonic treatment provided an additional increase in
the extraction yield, raised the solubility, reduced the
particle size, changed the structure, and improved the
functional properties of krill proteins, e.g. emulsifying
and foaming capacity, foam stability, etc. [39].
A combination of electrochemically activated
water, isoelectric precipitation, as well as isoelectronic
precipitation and electrochemically activated water
treatment (IP-EWT) provided a high recovery rate
(≥ 50%) of protein concentrate from heat stabilized
defatted rice bran [40]. The protein fraction contained
65.1 wt% protein and had a high amino acid value
(76.6%). A Sodium Dodecyl Sulphate Polyacrylamide
Gel Electrophoresis and an immunoblotting analysis
showed no signs of allergenic rice protein or heavy
metals in the protein fractions. The combined IP-EWT
process was environmentally friendly. It yielded highly
concentrated and safe protein from plant materials
without enzymes or chemicals, e.g. organic solvents,
buffering agents, surfactants, etc.
Electrochemically activated water proved effective
in the extraction of dry material from soybean
meal [41]. Solutions of anolyte and catholyte had a
Figure 4 Gel electrophoresis of protein solutions in water
or in the fraction of electrochemically activated fractions
(catholyte, anolyte): (a) albumin, (b) gelatin, (c) casein
kDA water catholyte anolyte
albumin
gelatin
kDA water catholyte anolyte
cazein
kDA water catholyte anolyte
a b
с
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high ability to extract proteins, carbohydrates, and
especially minerals. The extracted proteins had a wellbalanced
amino acid composition, which meant they
could serve as ingredients in various functional foods.
Electrochemically activated water gives the food
industry an important alternative to chemical reagents.
In future, it can become an effective tool for functional
modification of proteins [41, 42].
CONCLUSION
The present research involved viscometry, UV
spectrometry, time-of-flight mass spectrometry of
secondary ions, and electrophoresis of bovine serum
albumin. All the methods confirmed a multifaceted
effect of the anodic and cathodic fractions of
electrochemically activated water on the structure
and properties of protein in aqueous solutions. The
protein monoproduct (serum albumin) was subject
to modification when interacting with fractions
of electrolyzed water. The oxidized fraction of
electrochemically activated water (anolyte) made
the protein solution more homogeneous in terms
of molecular composition. The research registered
a significant unified effect of anolyte with a high
concentration of hydrogen peroxide on the disulfide
bond of amino acid residues, e.g. cysteine.
However, the mechanism of action of the reduced
fraction of electrochemically activated water (catholyte)
still remains unclear. The catholyte has a pronounced
antioxidant activity, but the activity of antioxidants
in biological systems can be studied only by the
compensation of oxidative stress to the normal level
of the redox potential of the medium (~ 360 mV). The
catholyte-based solutions of bovine serum albumin had
an abnormally negative potential (–800 mV), which
was not induced under physiological conditions or
pathological changes. Unlike the control samples, the
experimental samples with electrochemically activated
water retained the initial viscosity for a long time. Their
viscosity was lower than that of the protein solution in
non-electrochemically activated water. This effect was
consistent with other physicochemical changes.
The obtained patterns revealed good prospects
for reagent-free control of protein food media in
technological processes. Less food additives and
technological aids during processing means the
possibility to modify the functional properties of
protein food ingredients, e.g. texturing isolates.
Electrochemically activated water can serve as a water
base for liquid protein-fortified products. The method
helps maintain the desirable viscosity, consistency, and
sensory properties of functional foods.
CONTRIBUTION
A.G. Pogorelov supervised the project and proofread
the final manuscript. L.G. Ipatova wrote and improved
the manuscript. M.A. Pogorelova obtained and
analyzed the data. A.L. Kuznetsov interpreted the data.
O.A. Suvorov designed the research concept.
CONFLICT OF INTEREST
The authors claim there is no conflict or interests
regarding the publication of this article.

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