Abstract (English):
Introduction. Mercury contamination is one of the most common environmental problems. The research objective was to study the qualitative composition and physicochemical properties of raw game meat obtained from the area near the Beloosipovo mercury deposit in order to define any possible contamination w ith xenobiotics. Study objects and methods. The research featured rib eye muscle tissue and soft flesh of elks shot on the hunting farms of the Kemerovo Region aka Kuzbass. Results and discussion. A complex set of experiments revealed the chemical composition of elk muscle tissue and flesh, as well as the mineral composition of elk muscle tissue. The samples were obtained from different parts of carcasses. The amino acid and fatty acid composition of elk muscle tissue made it possible to describe the biological value, mineral composition, and vitamin profile of elk meat. The physicochemical analysis included toughness, cooking losses, and moisture-retaining capacity, i.e. the properties that ensure juiciness. The research also featured the accumulation of xenobiotics in elk meat samples obtained from the biosinosis near the Beloosipovo merc ury deposit. Conclusion. The slaughter yield of elk meat was 51–53%, which exceeds the average yield of farm cattle meat by 4–6%. The moisture content was 73–78%, while the content of protein was between 20–24% and depended on the anatomical location of the muscle sample; the fat content reached 0.75–1.75%. The mercury accumulation at different storage temperature conditions ranged from 0.004 ± 0.001 to 0.009 ± 0.001 mg/kg, while the max imum allowable concentration of mercury is 0.03 mg/kg.

Keywords:
Elk, mercury, biocenosis, meat, chemical composition, function al and technological properties, aging

Introduction
Environmental pollution has been the main concern
of ecologists, doctors, and food manufacturers for the
last several decades [1].
Heavy metals and mercury are one of the most
widespread and dangerous environmental pollutants.
Massive mercury poisoning occurred in the 1950s-1970s
as a result of the consumption of fish from mercurycontaminated
water sources. The massive character of
this phenomenon also triggered extensive research on
the effect of mercury on terrestrial ecosystems [2–4].
Short-chain alkyl mercury compounds cause the
greatest ecotoxicological hazard. They form strong
bonds with sulfur and weaker bonds with nitrogen,
oxygen, and halogens. Strong mineral acids break the
mercury-carbon bond to form inorganic compounds.
Mercury has the highest ionization potential among
other chalcophilic elements Due to this geochemical
feature, mercury can be reduced to its atomic form and
is highly resistant to oxygen and acids [5]. Mercury is
scattered in the earth’s crust: its deposits have a natural
content of 0.02% [6–8]. In addition to the atomic state,
mercury occurs in a bivalent and univalent state [9].
E.B. Swain et al. claim that the air usually contains up
to 5000 tons of mercury vapor or aerosol, and elemental
mercury vapors can remain in the atmosphere for
1–2 years [10]. Reactive ionic forms persist in the
atmosphere from several hours to several days [11]. In lowpolluted
air, the concentration of mercury is 0.8–1.2 ng/m3.
However, near large mercury deposits it can be as high as
240 ng/m3, and near gas deposits – 70 000 ng/m3, while
the average content of mercury is 0.5–2.0 ng/m 3 [12].
L. Ebinghaus et al. (1999) and E.G. Pacyna et al.
(2006) proved that anthropogenic impact increases
the man-induced component in the biogeochemical
cycle, as well as the emigration and redistribution of
natural mercury compounds [13, 14]. In nature, mercury
compounds are highly volatile and rise in the air quite
easily. In addition, mercury compounds are highly soluble
in water. Mercury is one of the most toxic elements in
the environment, with organic and inorganic mercury
being the main forms found in food samples [15].
When dissolved in water, mercury forms strong
soluble complex compounds with various organic
substances. Methylmercury (MeHg+) results from mercury
ions Hg2+ and methyl radicals CH3, which can be of
different origins, including bacterial. In low salinity water,
methylmercury ion HgCH3
+ and hydroxymethylmercury
СН3НgОН are the most popular compounds of mercury.
In natural water pools, humic and fulvic acids are
the most widespread donors of methyl groups, while
the content of humic acids in soil is also very high.
Mercury methylation depends on the ionization of the
abovementioned acids, the optimal pH values for these
reactions being 6–8 [16–18].
The Kemerovo Region covers an area of about
95.5 thousand km2. It is a large mining, processing,
chemical, and agricultural center.
The Kemerovo State University conducted an
expedition to the area of t he Beloosipovo mercury deposit
(Krapivinsky district). The team included scientists of
the Institute of Biology, Ecology, and Natural Resources
and was led by D.V. Sushchev, Candidate of Biological
Sciences. The team established the patterns of mercury
accumulation and distribution in various components of
the terrestrial ecosystem. They determined the mercury
content in soil, herbaceous plants, arthropods, and small
mammals, which they harvested in various biotopes
near the mercury deposit. A small plant evaporated
мясного сырья, а также изучение степени накопления ксенобиотиков в мясе диких животных, полученных в условиях
биоценоза Белоосиповского ртутного месторождения.
Объекты и методы исследования. Мышечная ткань длиннейшей мышцы спины, а также мякоть мяса лосей, добытых
ружейным способом егерями в охотничьих хозяйствах Кемеровской о бласти – Кузбасса.
Результаты и их обсуждение. В ходе комплексных исследований был изучен химический состав мышечной ткани и мякоти
мяса лося, минеральный состав мышечной ткани лося, полученной из разных анатомических частей туши животного.
Биоологическую ценность мяса лося оценивали по результатам изучения аминокислотного и жирнокислотного состава
мышечной ткани, а также минерального и витаминного состава. Были изучены физико-химические показатели мяса
лося, характеризующие его жесткость, потери при тепловой обработке, способность связывать и удерживать влагу, что
обеспечивает его сочность. Завершающий этап исследований связан с изучением накопления ксенобиотиков в опытных
образцах нетрадиционного мясного сырья, полученного вблизи райо на Белоосиповского ртутного месторождения.
Выводы. Убойный выход составил 51–53%, что превышает выход мяса крупного рогатого скота на 4–6%. По химическому
составу содержание влаги в мясе лося составило 73–78%, белка 20–24%, в зависимости от анатомического расположения
мышц, жира 0,75–1,75%. Динамика накопления изменения ртути в мясе лося при разных температурных режимах его
хранения составляла в пределах от 0,004 ± 0,001 до 0,009 ± 0,00 1 мг/ кг (при ПДК 0,03 мг/кг).
Ключевые слова. Лось, ртуть, биоценоз, мясо, химический состав, функционально-технологические свойства, выдержка
Для цитирования: Просеков А. Ю., Альтшуллер О. Г., Курбанова М. Г. Исследование качества и безопасности мяса
диких животных, полученного в условиях биоценоза Белоосиповского ртутного месторождения // Техника и технология
пищевых производств. 2021. Т. 51. № 4. С. 654–663. (На англ.). https://doi.org/10.21603/2074-9414-2021-4-654-663.
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Prosekov A.Yu. et al. Food Processing: Techniques and Technology, 2021, vol. 51, no. 4, pp. 654–663
mercury from ore in the Belaya Osipova river valley
in 1969–1975 (https://www.krapivino.ru/node/15303).
Based on the e-catalog of geological documents
(Russian Federal Geological Fund), specialists from the
Kemerovo State University referred the Beloosipovo
mercury deposit to the Kuznetsk fault zone. The
mineralization here is uneven and scattered. The mercury
deposit is estimated as 124 tons, cinnabar (HgS) being the
main ore-bearing mineral. The deposit has a hydrothermal
low-temperature origin and is located in the zone of
deep and echelon faults. Mercury manifests itself here
as occasional ore occurrences, points of mineralization,
concentrate and geochemical aureoles, etc. Areas of
high mercury concentration intersperse with barren
ones. The area featured in the present research is part
of the Pezas-Beloosipovo mercury ore zone and the
Beloosipovo mercury ore deposit [19].
The highest concentration of mercury is 1.5 km
north of the mine: soil – 0.72 and 0.96 mg/kg, plants –
0.064 mg/kg, insects – 0.063 mg/kg, rodents – 0.091 mg/kg,
insectivores – 0.056 mg/kg. The maximum allowable
concentration (MAC) of mercury in soil is 2.1 mg/kg.
Therefore, the mercury concentration in the local soil
was well within the norm (0.72 and 0.96 mg/kg).
Soil plays an important role in the global
biogeochemical cycle of mercury. As it settles on the
soil surface, its further route into aquatic ecosystems
largely depends on terrestrial ecosystems [20, 21]. In
addition to elemental mercury, soil contains inorganic
and organic compounds [22]. Inorganic compounds
exist in mobile (water- and acid-soluble), oxide, and
sulfide forms.
Mercury concentration is known to be much lower
in the soils of national parks with their minimal external
anthropogenic impact than in the areas affected by human
economic activities.
All forms of mercury in soils can be divided into
four types:
1) water-soluble mercury is described as readily available
to plants;
2) mercury soluble in an acetate-ammonium buffer
solution (pH 4.8) is believed to be conditionally easily
available to plants;
3) acid-soluble mercury is classified as potentially
available to plants;
4) alkali-soluble forms of mercury are conditionally
associated with mobile humic substances.
The content of mercury in one and the same type
of soil can be different as it depends on the adjacent
landscapes. For instance, its concentration is lower in
separate eluvium than in conjugated transeluvial and
super-aquatic soils, which is associated with migrationaccumulative
processes.
In continental biogeocenoses, mercury concentration
increases in the following order: plants > insects > soil
microorganisms > herbivorous mammals > carnivorous
mammals > macromycetes [23].
In 2018–2021, water samples from the Belaya
Osipova exceeded the MAC for mercury by 5–20%.
Probably, the groundwater and surface floods are leaching
mercury compounds from the deposit. However, the
biological diversity proves that such concentrations
have no pronounced impact on the local ecosystem.
In fact, the concentration of mercury goes down as it
moves up the food chains.
The Beloosipovo mercury deposit is surrounded by
taiga with its typical flora and fauna, including game
animals and birds. Professor A.Yu. Prosekov also
commented on the diversity of Beloosipovo flora in his
article Migration of Mercury in the Food Chains of the
Beloosipovo Biocenosis. The local taiga is predominated
by Siberian spruce (Abies sibirica Ledeb.), aspen (Populus
tremula L.), birch (Betula pubescens Ehrh., Betula
pendula Roth), and lush herbaceous vegetation up to
three meters tall. The rich undergrowth is formed by such
shrubs as goat willow (Salix caprea L.), cranberry bush
(Viburnum opulus L.), pea shrub (Caragana arborescens
Lam.), Siberian mountain ash (Sorbus sibirica Hedl.),
and bird cherry (Padus avium Mill.). Some undergrowth
areas are represented by sparse shrubbery, which is
known to attract wild animals, such as elk.
The list of herbaceous plants includes melancholy
thistle (Cirsium heterophyllum (L.) Hill.), millet grass
(Milium effusum L.), dissected hogweed (Heracleum
dissectum Ledeb.), wild chervil (Anthriscus sylvestris (L.),
cacalia (Cacalia hastata L.), Siberian hawk’s beard
(Crepis sibirica L.), northern wolfsbane (Aconitum
septentrionale Koelle), meadowsweet (Filipendula
ulmaria (L.) Maxim.), Siberian globeflower (Trollius
Figure 1. Elk population in the Krapivino district
465
497
498
491
177
2015 2016 2017 2018 2019
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Просеков А. Ю. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 4 С. 654–663
asiaticus L.), and giant fescue (Festuca gigantea (L.)
Vill.). All these plants serve as food base for taiga fauna.
Forest phytocenoses prevail in the research area, e.g.
aspen-birch-fir forest with lush tall grass and occasional
Siberian spruces. The growing anthropogenic load makes
it necessary to study the patterns of its effect on the
local wild animal population. Professor A.Yu. Prosekov
described the changes in the elk population in his research
Effect of Forest Coverage on Elk Population in Kuzbass.
Fig. 1 illustrates the pattern of elk population in the
Krapivino district in 2015–2019 as reported by the
Department of Wildlife Protection of the Kemerovo
Region (Fig. 1) [24–26].
In 2017, the elk population reached its peak, while
the total rise for 2015–2019 was 163%. The area of
the hunting grounds in the Krapivino district is 8328
hectares, i.e. 805 hectares of forest per animal, which
provides a fairly good forage base [25–27].
Elks (Alces a. Pfizenmayeri Zukowski) avoid dense
forests. They prefer sparse forests and overgrown
clearings, glades, and meadows that are rich in forage.
The vast burnt-out areas with young plants are home to a
large elk population. Elks spend all seasons in mixed and
deciduous forests. In summer, they eat leaves, reaching
as far as their considerable height allows them. They
feed on tall grasses in burnt-out areas and logging spots.
Late in summer, they eat all kinds of mushrooms, even
fly agarics – for medicinal purposes. In September,
elks start eating shoots and twigs, and by November
they almost completely switch to browse forage. Their
daily food intake varies from season to season. An adult
elk consumes 35 kg of food per day in summer and
12–15 kg in winter, i.e. about seven tons of plant food
per year. If elk population increases, they can damage
forest nurseries and plantings. Elks use every opportunity
to lick salt, sometimes even the salt mix that is used to
melt snow on highways [28, 29].
The elk is a game animal, which makes its meat an
object of research interest. Its quality and safety depends
on the fact whether it accumulates such xenobiotics as
mercury. Experimental studies and chance finds prove
that 0.1–200 mg of mercury per 1 kg of wet weight
can destroy the normal reproduction pattern and life
of warm-blooded animals, depending on numerous
factors [30].
Xenobiotic contamination of food raw materials
and products usually corresponds with the degree of
environmental pollution. Moving along the food chain,
contaminants enter human body and cause serious health
problems. Food chains are one of the main routes
that harmful chemicals take to get into human body.
Science knows more than nine million xenobiotics of
various nature. According to the Food and Agriculture
Organization (FAO) and the World Health Organization
(WHO), people consume 80–95% of contaminants with
food and 4–7% with drinking water, while 1–2% enters
human body from the air through the skin.
The research objective was to study the chemical
composition, functional, technological, and physicochemical
properties, and the accumulation of
xenobiotics in the raw elk meat obtained from the
biocenosis of the Beloosipovo mercury deposit.
The goal was to define:
– the anatomical and chemical composition of elk meat
from the forests of the Krapivino region in the vicinity
of the Beloosipovo mercury deposit;
– the amino acid, fatty acid, and mineral composition
of elk meat, as well as its functional and technological
properties;
– the degree of accumulation of mercury in meat samples
in their native state during storage and after various
methods of processing.
Study objects and methods
The research featured muscle tissue from the rib
eye area and fat and muscle tissue from the hind legs
of three elks (two males, one female) shot by the game
wardens in the hunting farms of the Kemerovo Region.
The sample description included the sex, body carcass
weight, and approximate age of the animals. The selected
samples were placed in a chemically neutral package,
sealed, and stored at –20 ± 2°C. The sampling procedure
and freshness test followed State Standard 7269-2015.
Moisture content was determined according to State
Standard 33319-2015; fat – by a Soxhlet extraction device
according to State Standard 23042-2015; total protein –
by the Kjeldahl method according to State Standard
25011-2017. All the biochemical studies involved modern
analytical equipment from the laboratory of the Research
Institute of Biotechnology, Kemerovo State University.
The list of indicators to be defined included the content
of fatty acids, vitamins, and macro- and microelements.
The mineral composition of the elk meat was determined
using an X-ray fluorescence spectrometer (Carl Zeiss
Jena). The amino acid composition was tested with an
automatic amino acid analyzer Aracus PMA GmbH, which
was approved by directives 98/64/EU and 2000/45/EU.
The method presupposed a cation-exchange separation
of amino acids with a stepwise pH gradient and a postcolumn
derivatization with ninhydrin. The fatty acid
composition was determined by gas chromatography
based on State Standard 55483-2013.
Hydrogen ions (pH) were studied by the potentiometric
method, the moisture-binding and moisture-retaining
capacity – by centrifugation and pressing. To define
the mercury concentration, the muscle tissue samples
were dried and subjected to dry ashing by the cold
vapor method in a Julia 5K device.
Results and discussion
Three elks were shot in the Krapivinsky district during
the hunting period (October – November) of 2017–2020
to assess the possible xenobiotic contamination of meat.
Sample 1 weighed 270.0 ± 10.5 kg, sample 2 – 310.0 ±
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Prosekov A.Yu. et al. Food Processing: Techniques and Technology, 2021, vol. 51, no. 4, pp. 654–663
13.5 kg, and sample 3 – 260.0 ± 10.0 kg. The carcasses
weighed 143.40 ± 7.15 kg, 165.20 ± 8.26 kg, and 137.80 ±
6.89 kg, respectively. The slaughter yield was within
51–53%, which exceeded the meat yield from farm
cattle (47–50%).
The elk is the largest representative of deer. The
elk meat samples were dark red, with coarse fiber and
almost no fat in the muscle tissue. Scarce fat stripes
were observed on the neck and chest. The highest fat
content was registered in the pelvic cavity and the lumbar
area. The fat was white and hard and crumbled at room
temperature. The melting point of fat from different
parts of the carcass ranged from 47.1 to 48.5°C.
The lymph nodes were oval and varied in size. They
were gray-white on the surface, while their peripheral
areas were darker, which suggests that the animals were
healthy.
The initial sensory analysis included boiling the
samples in order to assess the quality of the broth.
The broth was transparent and had a typical meaty
smell, which indicated the good quality of the meat.
The freshness test procedure for game meat included
a complex of studies, which consisted of a sensory
evaluation, bacterioscopy of deep layers, cooking test and
ammonia reaction with Nessler’s reagent. The complex
analysis confirmed the freshness of the meat samples.
Table 1 shows the anatomical and chemical
composition of the elk meat.
The average morphological composition of elk
carcasses was as follows (% of the carcass weight).
Muscle tissue predominated, the yield being 73 ± 2%; the
content of bones and cartilage was 18 ± 2%, connective
tissue – 8 ± 1%, and fat – 0.7 ± 1%. Table 1 shows that
the moisture content in the rib eye sample was 78.14 ±
3.90 g/100 g, which exceeded this indicator in the average
flesh sample by 5.91%. The samples demonstrated a
high protein content of 23.62%, which exceeded that
of farm animal meat, e.g. in pork and beef, the mass
fraction of protein is 14–15 and 16–17%, respectively.
The protein:fat ratio was 1:0.07, while for farm cattle
this ratio is 1:0.5. Unlike more traditional raw meat,
elk meat has low fat content, which proves its dietary
properties and a lower chol esterol profile.
Table 1. Morphological and chemical composition of elk meat (n = 3)
Indicator № 1 № 2 № 3 Mean value
Anatomical composition, kg
Muscle tissue 105.39 ± 5.15 121.42 ± 6.08 101.28± 5.67 109.36 ± 5.46
Fat 0.86 ± 0.11 1.16 ± 0.09 0.84 ± 0.13 0.95 ± 0.11
Connective tissue 11.23 ± 1.75 13.05 ± 0.96 10.88± 1.18 11.72 ± 0.58
Bones and cartilage 25.81± 1.99 29.81 ± 1.69 24.82 ± 1.16 26.81 ± 1.60
Chemical composition of rib eye sample, g/100 g
Moisture 77.85 ± 3.11 78.88 ± 2.94 77.61 ± 3.18 78.14 ± 3.90
Total protein 19.88 ± 0.79 21.56 ± 0.86 19.75 ± 0.78 20.39 ± 0.81
Fat 0.77 ± 0.03 0.82 ± 0.03 0.68 ± 0.02 0.75 ± 0.03
Ash 0.99 ± 0.04 1.23 ± 0.04 1.05 ± 0.04 1.09 ± 0.04
Chemical composition of the average sample of flesh, g/100 g
Moisture 72.62 ± 2.27 74.14 ± 2.13 73.82 ± 2.04 73.52 ± 3.65
Total protein 23.32 ± 0.85 24.65 ± 1.05 22.91 ± 0.88 23.62 ± 1.18
Fat 1.70 ± 0.06 1.73 ± 0.07 1.80 ± 0.07 1.74 ± 0.08
Ash 1.21 ± 0.05 1.42 ± 0.04 1.34 ± 0.06 1.32 ± 0.06
Other substances 1.31 ± 0.05 1.48 ± 0.05 1.30 ± 0.04 1.36 ± 0.04
Table 2. Amino acid composition of elk meat (rib eye), g/100 g of protein (n = 3)
Amino acid Content Amino acid Content
Essential Nonessential
Valine 2.55 ± 0.06 Methionine + Cysteine 2.87 ± 0.08
Isoleucine 3.83 ± 0.11 Hydroxyproline 0.55 ± 0.01
Leucine 3.58 ± 0.10 Glutamine 3.86 ± 0.11
Lysine 4.86 ± 0.24 Proline 0.98 ± 0.02
Methionine 1.75 ± 0.04 Serine 2.62 ± 0.07
Tryptophan 3.96 ± 0.02 Glycine 2.82 ± 0.08
Threonine 3.64 ± 0.10 Alanin 2.77 ± 0.08
Phenylalanine 1.73 ± 0.05 Arginine 3.66 ± 0.11
Total 25.90 ± 0.68 Total 20.13 ± 0.58
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Просеков А. Ю. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 4 С. 654–663
The biological value of meat depends on the main
nutrients, in particular, amino and fatty acids. Therefore,
the next task was to determine these indicators for the
rib eye samples (Table 2–3, Fig. 2).
The total amount of essential amino acids in the
elk rib eye samples exceeded the nonessential ones by
23%. The total amino acid level was 46.03 ± 1.38 g
per 100 g of protein.
The list of the most abundant essential amino acids
started with lysine (4.86 ± 0.24), tryptophan (3.96 ±
0.02), and isoleucine (3.83 ± 0.11). The nonessential
amino acids were dominated by glutamine 3.86 ± 0.11
and arginine 3.66 ± 0.11 g/100 g of protein.
The ratio of the essential and nonessential amino acids
was high in the rib eye samples: the protein quality index
(PQI) was 7.2, with a rather high content of tryptophan
and a low content of hydroxyproline. For beef, the
PQI is 5.0–5.5.
Oleic acid proved to be the most abundant unsaturated
fatty acid. It improves human metabolism and immune
system; it is good against cholesterol and insulin
resistance. Oleic acid occupied 85% of the total amount
of unsaturated fatty acids. Palmitic acid topped the list
of saturated fatty acids. The total amount of saturated
fatty acids in the rib eye sample was 33.32 ± 0.98%,
that of unsaturated – 51.83 ± 1.55%.
Minerals also increase the nutritional and biological
value of meat. They are important for metabolism,
growth, and development. Table 4 shows the mineral
composition of the elk meat.
12.844' Asp
16.523' Ser
17.642' Thr
19.738' Glu
21.724'
25.083' Pro
27.768' Gly
28.716' Ala
31.653' Cys
33.276' Met
34.810' Ile
35.691' Leu
37.753' Tyr
41.203' Phe
44.166' His
45.028'
46.404'
52.462' Lys
54.591' NH4
60.962' Arg
0
80
160
240
320
400
480
560
640
720
800
mV
15 20 25 30 35 40 45 50 55 60 min
1 – tryptophan, 2 – threonine, 3 – isoleucine, 4 – hydroxyproli ne, 5 – serine, 6 – glycine, 7 – alanine, 8 – valine, 9 – methi onine,
10 – cystine, 11 – leucine, 12 – glutamine, 13 – proline, 14 – phenylalanine, 15 – lysine, 16 – arginine, 17 – methionine + cy steine
Figure 2. Chromatographic profile of the amino acid composition of elk rib eye
Table 3. Fatty acid composition of elk rib eye, % (n = 3)
Acid Content Acid Content
Saturated fatty acids Unsaturated fatty acids
Lauric 1.09 ± 0.03 Palmitooleic 6.54 ± 0.19
Myristic 0.75 ± 0.02 Oleic 44.02 ± 1.32
Palmitic 26.13 ± 0.74 Linoleic 1.10 ± 0.03
Stearic 5.26 ± 0.15 Linolenic 0.17 ± 0.01
Arachinic 0.09 ± 0.01 Total 51.83 ± 1.55
Total 33.32 ± 0.98
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The samples proved to be rich in potassium (306.33 ±
6.12 mg/100 g), sulfur (196.42 ± 3.95 mg/100 g), and
phosphorus (195.02 ± 3.85 mg/100 g). Unlike beef and
pork, elk meat appeared to contain a lot of potassium,
sodium, magnesium, iron, and phosphorus. For example,
elk meat has more potassium than pork and beef by 7
and 10%, sodium – by 24 and 35%, and iron – by 17 and
30%, respectively. Iron with its 2.90 ± 0.08 mg/100 g
was the predominant trace element.
The quality of the muscle tissue was tested according
to its physicochemical parameters, cooking losses,
and moisture-retaining properties, i.e. the properties
that defined the juiciness of the meat. Another test
measured the pH value, which depended on biochemical
changes related to maturation processes and glycogen
conversion (Table 5).
The analysis of the functional and technological
properties involved moisture-binding capacity (73.36 ±
3.50%) and water-retaining capacity (59.57 ± 1.78%).
The hydrogen index (pH) of meat varied from 5.8 to
6.2 units, which means that a small amount of lactic acid
prevented the development of putrefactive microflora.
The water-retaining capacity depends on the ability
of proteins to bind water in various ways, both on the
surface and inside. Therefore, it is responsible for
juiciness, tenderness, market quality, cooking and freezing
losses, etc.
The elk meat samples appeared to be quite tender:
the shearing strength was 2.36 ± 0.07 kg/cm 2, and the
cooking losses were only 20.19 ± 1.20%. The size of
the rib eye characterizes the fleshing of carcass; this
indicator was 31.67 ± 0.95 cm2, which meant a relatively
high meat production.
The final stage of the research featured the
accumulation of xenobiotics, in particular, mercury.
The high toxicity of mercury depends on the type
of compound. Various mercury compounds differ in
the way they are absorbed, get involved into metabolic
Table 4. Mineral profile of elk meat, mg/100 g (n = 3)
Micronutrients № 1 № 2 № 3 Mean value
Iron 2.91 ± 0.09 2.88 ± 0.08 2.93 ± 0.08 2.90 ± 0.08
Copper 5.48 ± 0.16 6.21 ± 0.18 6.33 ± 0.18 6.01 ± 0.18
Calcium 10.22 ± 0.30 10.31 ± 0.30 11.01 ± 0.35 10.51 ± 0.33
Magnesium 24.55 ± 0.49 24.41 ± 0.47 23.88 ± 0.45 24.28 ± 0.47
Sodium 77.41 ± 1.54 76.88 ± 1.53 77.32 ± 1.54 77.20 ± 1.54
Zink 125.66 ± 2.51 133.45 ± 2.66 129.75 ± 2.19 129.62 ± 2.28
Phosphor 194.43 ± 3.88 194.41 ± 3.88 196.22 ± 3.81 195.02 ± 3.85
Sulfur 195.54 ± 3.91 197.21 ± 3.94 196.51 ± 3.93 196.42 ± 3.95
Potassium 305.22 ± 6.10 307.33 ± 6.14 306.44 ± 6.11 306.33 ± 6.12
Table 5. Physicochemical, functional, and technological properties of elk muscle tissue (n = 3)
Indicator № 1 № 2 № 3 Mean value
рН 5.80 ± 0.12 6.00 ± 0.14 6.2 ± 0.16 6.00 ± 0.14
Color intensity, Е×1,000 375.80 ± 11.10 376.91 ± 10.2 375.00 ± 10.5 375.90 ± 10.47
Moisture-binding capacity, % 74.66 ± 2.23 72.33 ± 2.16 73.11 ± 2.19 73.36 ± 3.50
Moisture-retaining capacity, % 58.62 ± 1.75 59.88 ± 1.79 60.21 ± 1.80 59.57 ± 1.78
Cooking loss, % 20.58 ± 1.21 18.99 ± 1.16 21.01 ± 1.23 20.19 ± 1.20
Rib eye area, cm2 (at ribs 12–13) 31.21 ± 0.93 32.01 ± 0.96 31.80 ± 0.95 31.67 ± 0.95
Shearing strength, kg/cm2 2.10 ± 0.06 2.59 ± 0.07 2.40 ± 0.07 2.36 ± 0.07
Table 6. Accumulation of mercury in elk muscle tissue during maturation (n = 3)
Exposure time Mercury concentration, mg/kg of solids Mean value
№ 1 № 2 № 3
At 20 ± 2°С
Control (fresh meat) 0.004 ± 0.001 0.003 ± 0.002 0.005 ± 0.001 0.004 ± 0.001
2 days 0.006 ± 0.002 0.005 ± 0.001 0.007 ± 0.001 0.006 ± 0.001
At –20 ± 2°С
5 days 0.005 ± 0.001 0.004 ± 0.001 0.007 ± 0.001 0.005 ± 0.001
10 days 0.007 ± 0.001 0.006 ± 0.001 0.009 ± 0.001 0.007 ± 0.001
15 days 0.009 ± 0.001 0.008 ± 0.001 0.012 ± 0.001 0.009 ± 0.001
661
Просеков А. Ю. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 4 С. 654–663
processes, and excreted from the body. Mercury is toxic
because it interacts with sulfhydryl proteins. By blocking
them, mercury changes their properties or inactivates a
number of vital enzymes. As it enters the cell, mercury
incorporates into the DNA, which can cause hereditary
disorders [31].
The brain exhibits a special affinity for methylmercury:
its ability to accumulate mercury is almost six times
higher than that of other organs. Inorganic mercury
compounds disrupt the metabolism of ascorbic acid,
calcium, copper, zinc, and selenium. Organic mercury
compounds affect the metabolism of proteins, cysteine,
ascorbic acid, tocopherols, iron, copper, manganese, and
selenium. It takes mercury compounds 70 days to leave
human body. Zinc and especially selenium can protect
human organism from mercury compounds. Selenium
forms a non-toxic selenomercury complex as a result
of demethylation of mercury. Ascorbic acid and copper
can lower the toxicity of inorganic mercury compounds,
while proteins, cysteine, and tocopherols help against
organic mercury compounds. The acceptable weekly
intake of mercury cannot exceed 0.3 mg. The acceptable
daily intake of mercury is 0.0006 mg per 1 kg of body
weight [31, 32].
The UN, WHO, and FAO developed the basic
indicators of food hygiene based on toxicological criteria:
MAC is the maximum allowable concentration of
contaminants in the air, water, and food from the point
of view of safety for human health. Daily exposure
to MAC for an arbitrarily long time does not trigger
diseases or health problems that can be detected by
modern research methods in the life of the present and
subsequent generations.
ADI is acceptable daily intake that does not affect
human health throughout life (mg/kg).
TDI is the tolerable daily intake calculated as ADI
multiplied by the average body weight (60–70 kg) that
a person can consume daily throughout life without
risk to health [33].
The content of mercury in elk muscle samples was
determined in fresh meat samples (control), after two
days of storage at 20 ± 2 °C, and on storage days 5,
10, and 15 at –20 ± 2 °C (Table 6).
Mercury concentration in the muscle tissue increased
with maturation, even at low temperatures. On storage
day 15 at –20 ± 2 °С, it increased by approximately
2.25–2.6 times. At room temperature, the rate of mercury
concentration in the muscle tissue doubled.
However, mercury concentrations at different
temperatures did not exceed the MAC value of
0.03 mg/kg.
On storage day 15 at low temperatures, several
samples were thawed and subjected to frying and boiling
to determine the mercury content. Boiling decreased the
mercury concentration by 22%. However, boiling does
not affect the concentration of xenobiotics in mushrooms.
In mushrooms, mercury is bound with amino groups
of nitrogen-containing compounds, and in meat – with
sulfur-containing amino acids. Frying decreased the
mercury concentration by 25%: this value could be
improved by subjecting the meat to preliminary grinding.
Conclusion
The present research revealed some useful data on
the composition and properties of raw elk meat, such as
mercury concentration and its patterns during storage.
The slaughter yield was 51–53%, which is
significantly higher than for farm cattle (45–47%). The
anatomical composition of elk carcass was as follows:
muscle tissue – 73 ± 2%, bones and cartilage – 18 ± 2%,
connective tissue – 8 ± 1%, fat tissue – 0.7 ± 1%.
The moisture content in the rib eye muscle tissue was
78.14 ± 3.90 g/100 g, which exceeded the average flesh
sample by 5.91%. The elk meat proved to have a high
protein content of 20–24%, while the protein:fat ratio
in the flesh sample was 1:0.07, which classifies the elk
meat as a dietary product.
The total level of amino acids was 46.03 ± 1.38 g/100 g
of protein, while the total amount of essential amino acids
in the rib eye tissue exceeded that of nonessential acids
by 23%. The total amount of saturated fatty acids in the
rib eye sample was 33.32 ± 0.98%, that of unsaturated
fatty acids – 51.83 ± 1.55%.
The mineral composition of elk meat was dominated
by potassium (306.33 ± 6.12 mg/100 g), sulfur (196.42 ±
3.95 mg/100 g), and phosphorus (195.02 ± 3.85 mg/100 g).
The water-binding capacity was 73.36 ± 3.50%,
while the water-retaining capacity was 59.57 ± 1.78%.
The pH of the elk meat varied from 5.8 to 6.2 units; the
shearing strength was 2.36 ± 0.07 kg/cm2. The cooking
losses were as low as 20.19 ± 1.20%.
The final set of experiments measured the level of
xenobiotics in the elk meat obtained from the biocenosis
of the Beloosipovo mercury deposit. The mercury content
did not exceed the maximum allowable concentration
of 0.03 mg/kg at different temperature conditions. At
room temperature storage, the change in the mercury
content in muscle tissue was twice as fast as in the frozen
samples. Heat treatment decreased the concentration
of mercury by 22–25%.
Contribution
All the authors contributed equally to the study and
bear equal responsibility for information published in
this article.
Conflict of interest
The authors declare that there is no conflict of interest
regarding the publication of this article.

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