ISSN 2074-9414 (Print),
ISSN 2313-1748 (Online)

Volume 54, Issue 1 (29.03.2024), 2024

1008
Abstract
Most domestic sparkling wines are made of traditional champagne grape varieties. However, indigenous Crimean cultivars could increase the output of high-quality original beverages if a proper technology was introduced.
This research featured young sparkling wines from Crimean grape varieties, i.e., Soldaya, Shabash, Kokur Beliy, Sary Pandas, Kefesiya, Dzhevat Kara, and Ekim Kara. Organic acids, sugars, glycerin, phenolic substances, and ethanol were determined by high performance liquid chromatography; the content of amine nitrogen was measured by formalin titration. The optical profile of the wine samples was subjected to the colorimetric method while their foamy properties were studied by bubbling the samples in a measuring cylinder. The sparkling properties depended on the rate of CO2 desorption; the volumetric method made it possible to define the CO2 content; the viscosity was measured using a viscometer. The sensory assessment followed State Standard 32051-2013, ISO 5492:2008, and ISO 11035:1994.
The samples of Kokur Beliy, Sary Pandas, and Soldaya received high tasting ratings (≥ 9.0 points), as did the red variety of Kefesiya (8.95 points). They demonstrated a clear typical aroma and a harmonious taste, as well as good foamy and sparkling properties. The maximal foam volume correlated with amine nitrogen (r = 0.762) while the sparkling properties correlated with the mass fraction of bound CO2 (r = 0.977). The red sparkling wine from the Kefesiya variety had a dark garnet color due to its high anthocyanins. It also contained quercetin and glycoside, which are known for their biological (P-vitamin) activity and powerful antioxidant properties. The early low-sugar (< 18 g/100 cm3) varieties of Dzhevat Kara and Ekim Kara had the same acidity but demonstrated a less diverse phenolic profile and were paler in color.
In this research, the indigenous Crimean grape cultivars of Kokur Beliy, Sary Pandas, Soldaya, and Kefesia showed good prospects for young sparkling wines. Other varieties needed special technologies to preserve their typical properties and the aroma/taste balance. The new technology makes it possible to obtain unique high-quality products right in the harvest year, thus increasing the range and volume of sparkling wine production.
855
Abstract
Table grapes that have lost their marketable appearance are considered waste products. However, such grapes still possess some technological properties that make it possible to use them as a raw material for wine and grape spirits. This research featured the effect of the composition and technology of table grape alcohols on the volatile compounds and sensory profile of grape beverages.
The study involved six white and six red grape beverages. In the test samples, the fermentation process was stopped by adding wine spirits and grape spirits obtained by rectification of distillates from table grapes. In the control samples, the procedure involved rectified grain alcohol. The physicochemical parameters of drinks and spirits were defined by standard methods. The highly volatile compounds were determined by gas chromatography. The sensory assessment was conducted by panelists from the Winemaking Research Center of the North-Caucasian Federal Scientific Center of Horticulture, Viticulture, and Winemaking.
In this study, the wine spirits and the grape spirits obtained from table grapes had no effect on the standard indicators, e.g., volatile acids and acetoin. However, they increased the mass concentrations of highly volatile compounds in the following manner: drinks with grain alcohol ˂ drinks with wine alcohol ˂ drinks with grape alcohol. The content of acetaldehyde increased by 10–14% while the contents of ethyl acetate, esters, and higher alcohols increased by 25–35, 4.5–8.5, and 15%, respectively. The furfural content increased by 0.4–1.4 mg/L in the samples with grape alcohol. The samples with white grape varieties acquired a more prominent floral-honey flavor whereas those with black grapes acquired hints of hazelnut and honey.
As a result of the study, it was found that wine alcohol and grape alcohol moderately increased the content of volatile compounds in drinks and had a positive effect on their sensory perception, which proves the expediency of their use in beverage technology.
855
Abstract
Traditional energy sources pollute the environment. Microbial fuel cells are an alternative energy source that can reduce the environmental burden. Microbial fuel cells also remove recalcitrant wastes from wastewater. This research featured the enzymatic potential of microbial isolates obtained from the Abakan Arzhan thermal spring.
The study involved isolates of the genera Geobacter, Thermomonas, and Rhodopseudomonas. The keratinolytic analysis was in line with State Standard R 55987-2014. The chitinolytic activity was determined by injecting a bacterial suspension on Petri dishes with a chitin-containing medium. The lipolytic analysis involved cultivating the isolates in Stern’s glycerol fuchsin broth. The xylan hydrolysis depended on the reducing sugars. The cellulase activity was measured according to the standard method recommended by the International Union of Pure and Applied Chemistry (IUPAC). The catalase potential was evaluated by the gasometric method on 1% gasoline media. The optimal parameters of consortium cultivation were determined by the voltage generated.
The Geobacter isolate had the maximal keratinolytic activity while the Thermomonas isolate demonstrated the maximal protein hydrolysis (80.1 ± 1.5%). Both Geobacter and Rhodopseudomonas showed good lytic activity against chitin with the lysis zone of ≥ 3 mm. The Geobacter isolate demonstrated as many as 350 units of xylanase activity and 365 units of cellulase activity; Thermomonas had 350 units of xylanase activity and 360 units of cellulase activity; Rhodopseudomonas showed 310 units of xylanase activity and 304 units of cellulase activity. The maximal catalase properties belonged to Geobacter (1.40 units) and Thermomonas (1.38 units). The maximal energy generation by bacterial consortia occurred at pH 8 and 45°C after 48 h of cultivation.
In this research, isolates of the genera Geobacter, Thermomonas, and Rhodopseudomonas from the Abakan Arzhan thermal spring were able to remove recalcitrant components, thus demonstrating good prospects for biological treatment of industrial wastewater.
845
Abstract
The fruit Mangifera laurina Blume lacks sufficient research attention, with no literature available on its physicochemical properties, proximate nutritional composition, carotenoid content, or enzyme liquefaction process. Therefore, we aimed to optimize the parameters for enzymatic liquefaction of M. laurina puree and comprehensively analyze its characteristics.
Homogenized pulp of M. laurina was treated with different enzymes (Pectinex Ultra SPL, Celluclast, Fungamyl, and Termamyl). Pectinex Ultra SPL was selected as the most effective enzyme as it significantly decreased viscosity and increased juice yield. Pectinex Ultra SPL was then used to treat the homogenized pulp at different concentrations (0–4.0%), different incubation times (0–2.5 h), and different incubation temperatures (25–60°C). We considered these parameters as independent variables and studied their effects on viscosity, juice yield, total soluble solids, pH, and color to establish optimum conditions for the enzymatic liquefaction of M. laurina pulp.
The recommended enzymatic liquefaction conditions were set as 2.0% Pectinex Ultra SPL at 45°C for 2.0 h. The optimized enzyme-liquefied mango puree showed a noteworthy decrease in total carotenoids (174.15 ± 0.04 µg/100 g), crude protein, crude fat, and crude fiber, compared to fresh mango puree. However, enzymatic liquefaction provided the mango puree with higher contents of moisture and ash, better water activity, and higher juice yield, compared to fresh mango puree.
Enzymatic liquefaction of fruit juice provides advantages in terms of improved digestion, increased yield, and enhanced economic profit. Its ability to enhance nutrient availability, increase extraction rates, and optimize production processes makes it a valuable technique in various food industries.
950
Abstract
Growing organic microgreens indoors requires a unified technological procedure with various external elicitors. The quality of seedlings depends on their ability to accumulate essential microelements. This research assessed the nutrient profile of mustard microgreens using the method of fractal calculation with repeating numerical series.
The experiment involved mustard (Brássica júncea L.) of the Nika variety grown in a closed box for 15 days under aggregation with an intensive 16-h photocycle (440 µmoL m2/s). The plants were inoculated with the endomycorrhizal fungus Glomus mosseae. A solution of fulvic acids (100 mg/L) served as a stabilizing organic additive and was introduced into the coconut substrate. The physical treatment included weak static electromagnetic field with magnetic induction (20 mT). The elemental analysis was performed by inductively coupled plasma atomic emission spectrometry on an ICPE-9000 device (Shimadzu, Japan).
According to the calculated indices of the microelement biocomposition, the best result belonged to the sample treated with fulvic acids and weak electromagnetic field (IndBcomL = 0.27). The resulting biomass of dry powder for elemental analysis was 10.2 g, which was twice as high as the values obtained in the control sample, not subjected to any external influences (5.2 g). All the variants with mycorrhization produced no positive effect on the total pool of microelements during vegetation. The increase in biomass averaged as low as 20%. Zinc increased by 33.3% while aluminum and iron decreased by 59.5 and 18.0%, respectively.
The neural network analysis of the microelements in mustard microgreens proved effective as a mathematical model for biochemical diagnostics of biomass quality. The method could be used to optimize the biotechnological process for other indoor crops as it makes it possible to partially substitute mineral fertilizers with organic and bacterial complex.
836
Abstract
Cloudberry (Rubus chamaemorus L.) and arctic raspberry (Rubus arcticus L.) are highly nutritional and medicinal but lowyield berries, with some populations being on the verge of extinction. Micropropagation biotechnologies are cost-effective and may provide healthy and plentiful planting material for these valuable berries. Clonal micropropagation of cloudberry and arctic raspberry requires new methods adapted for Russian varieties. This research featured the effect of sterilizing agents on the survival rate of explants of R. chamaemorus and R. arcticus, as well as the effect of growth regulators in the nutrient medium on their organogenesis in vitro.
Berries obtained from regenerant plants of R. chamaemorus (Arkhangelsk and Vologda varieties) and R. arcticus (Sofia and Galina varieties) underwent a biochemical analysis. Further research involved the effect of sterilizing agents and exposure time on the viability of explants, as well as the effect of the nutrient medium composition and the concentration of growth regulators on the development of microshoots and roots in vitro.
In case of lateral buds, the highest survival rate of both types of explants (80–96%) belonged to the samples sterilized with 0.2% silver nitrate and 5% Lysoformin 3000 for 15 min. In case of etiolated shoots (79–100%), it was the samples treated with 0.2% silver nitrate, 0.01% Nika 2, and 5% Lysoformin 3000 for 10 min. The maximal total length of microshoots in R. chamaemorus (19.4–22.7 cm) was registered at 0.1 mg/L Cytodef in the Murashige and Skoog medium. The maximal total length of roots (46.0–56.6 cm) was obtained when the medium contained 0.5 mL/L indolylacetic acid. As for R. arcticus, the maximal total lengths of microshoots (22.4–22.8 cm) and roots (86.6–89.3 cm) occurred at the same concentrations of growth regulators on 1/2 Murashige and Skoog medium.
In this research, Cytodef and indolylacetic acid applied in the process of clonal micropropagation of R. chamaemorus and R. arcticus made it possible to increase the yield of high-quality planting material for commercial plantations.
819
Abstract
Quails (Coturnix coturnix (Linnaeus, 1758)) are the only migratory Galliformes species. Quails are nestling ground-dwelling birds, feeding on seeds and crawling insects. Wild quails inhabit many parts of Russia. Quail farming is quite popular because quail meat is low in calories and possesses a number of beneficial properties, e.g., it is rich in proteins, contains little fat and virtually no carbohydrates, etc. As a rule, quails winter in Transcaucasia and Southern Europe; however, they sometimes prefer to stay in southern regions for the winter. This article introduces the autumn food habits of quails in the Central Ciscaucasia.
The research relied on the analysis of stomach contents of 156 birds killed by hunters or hit by vehicles in several districts of the Stavropol Region. The material was collected in the autumn in 2008–2021.
In the Central Ciscaucasia, quails are mesophiles and inhabit abandoned wheat and pea fields. The population fluctuates from year to year, depending on spring weather conditions. Their optimal nestling grounds include irrigated fields and areas near canals and ponds. In the steppe regions, they prefer agricultural areas, e.g., orchards, vineyards, holiday villages, sheep sheds, green belts along fields, roads, and railways, etc. Being phytophages, they rely on plant and, to a lesser extent, animal forage.
In the autumn, they feeding on green plants, wheat grain, seeds of cultivated and wild plants, and insect larvae.
872
Abstract
Partial replacement of wheat flour in foodstuffs is of great importance in the food industry. Muffins are a type of semi-sweet cake that is traditionally made from wheat flour. They are especially favored by children and senior citizens. Muffins have a long shelf life, which also contributes to their popularity. However, gluten, the main protein in wheat flour, is commonly associated with celiac disease. Gluten consists of two fractions: gliadins and glutenins.
In this experiment, the original muffins contained 100% wheat flour. Then, we replaced a portion of wheat flour with 25, 50, and 75% quinoa flour. The samples were stored for 0, 2, and 4 weeks. After that, gliadin proteins were extracted with 70% (v/v) ethanol. We separated gliadin using a high-performance liquid chromatograph (Agilent Technologies 1260 Infinity, USA) and measured the total amount of gliadin protein and the amount of gliadin proteins per fraction. The absorbance tests were conducted at 210 nm.
The gliadin protein content was significantly reduced to the wheat vs. quinoa ratio of 50:50 because quinoa is gluten-free, even though it is rich in protein. During the storage time of 0, 2, and 4 weeks, the protein content fell down in the samples with the wheat vs. quinoa ratios of 100:0, 75:25, and 50:50. However, the muffins with 25% wheat flour and 75% quinoa demonstrated an increase in gliadin content.
The results obtained could be a good starting point for the development of high-fiber, gluten-free, and more nutritionally valuable muffins.
818
Abstract
Whipped yeast-free bakery products require effective energy supply to dough in order to optimize energy consumption, baking time, and quality. This article introduces a verified mathematical model of microwave and convective baking for whipped bread based on heat and mass exchange equations.
A full-scale experiment to verify the calculations involved dough samples with a humidity of 56 ± 1%. The samples underwent microwave and convective processing until the temperature in the crumb center reached 98 ± 1°C.
The mathematical model was formalized as energy and mass conservation equations, which made it possible to consider baking as a non-stationary process of heat and mass transfer of moisture in an isotropic incompressible continuous medium in the diffusion approximation. The equation took into account the unstable phase transition boundary. The practical verification showed the mean error for microwave baking as 14.5% in temperature and 18.2% in moisture content. For convective baking, the results included 12.6% in temperature and 9.7% in moisture content. The mathematical model proved adequate to the real processes of heat and mass transfer. The error in calculating the temperature and moisture content fields was sufficient tooptimize the process.
The physical and mathematical model of the baking process made it possible to evaluate the effect of technological variables on the temperature and moisture concentration fields in the dough samples. The mathematical model and the computational experiment can be used to identify static and dynamic characteristics of baking as an object of automatic control, i.e., to identify optimal control channels and actions, as well as to adjust the automatic control system to specific quality indicators.
943
Abstract
The food industry is currently demonstrating a tendency to substitute traditional high-humidity raw materials with their dry analogues. This research introduces new designs of vertical vibrating mixers that could preprogram flour mix quality. The vertical continuous vibration mixers designed for granular materials showed a good potential for a wider scope of application.
The experiment involved high-quality wheat flour, sugar, salt, egg powder, and powdered milk, as well as three vertical mixers, i.e., a lifting mixer, a flow mixer, and a cascade mixer.
Wheat flour entered the working body of the mixer and came into a stable vibration-boiling state in layers of ≤ 35 mm with a vibration amplitude of 4.5 mm and a frequency of ≥ 20 Hz. The speed rate of the flour increased together with the oscillation frequency of the working body and the size of the perforation area but went down as the layer grew wider. The efficiency increased following the increase in the perforation area on the spiral surface and depended on the maximal thickness of the dough layer. The flow vibrating mixer proved to be the most effective one. The frequency of pulse feeding of ingredients into the mixer was ≤ 50% (Vc ≤ 14.5%) to obtain flour mixes of satisfactory quality while good-quality mixes required 25% average time the particles spent in the mixer (Vc ≤ 6%).
The results obtained can be used to design technological lines for flour mix production.
804
Abstract
The food industry and agriculture use such electrophysical technologies as ozonation, pulsed electric field, and low-temperature plasma. They increase the shelf-life of food products, as well as help to advance food processing. This article features pretreatment with a low-voltage spark-discharge plasma channel as a means to increase the efficiency of grain drying.
The grain material involved three samples of soft wheat seeds. Sample 1 was subjected to direct contact with the electrodes while sample 2 underwent treatment on a dielectric substrate. The control remained untreated. The kinetics of grain-drying in the open air was studied using a thermal agent at 110°C after pre-treatment with a low-voltage spark-discharge plasma channel. This experiment also involved scanning electron microscopy tools to detect changes in surface structure.
The electron microscopy showed that the dielectric substrate accelerated moisture removal, probably as a result of the emerging surface effects that developed a new continuum in the grain structure. This treatment made it possible to reduce the drying time by 15–25%, compared to the control sample. The drying rate curves demonstrated acceleration in the initial period, associated with additional electroosmotic forces and changes in the absorption properties. The samples treated with low-voltage spark-discharge plasma channel showed a 20% reduction in total energy consumption.
Electrophysical technology based on a low-voltage spark-discharge plasma channel proved to be an effective pre-drying procedure. Further research is needed to scale the technology in a flow mode and to identify its effect on shelf-life.
848
Abstract
Russia enjoys a stable demand for flour products, including those obtained by the dry method of starch and gluten production. This study featured pneumocentrifugal parameters of fine particles in a spiral separator that classified milled grain into fractions, separated the solid phase from air, and identified the high-protein flour fraction in the flow.
Pneumatically classified flour was subjected to mathematical modeling and experimental research. The analysis of movement and deposition of particles in the working area covered particle mass, density, air-flow rate, and geometry, as well as their effect on the trajectory of particle movement and deposition. The experiment also involved the effect of air-flow rate and air-mix concentration on the classification efficiency.
Particles from various grinding and break systems demonstrated classification modes that differed in soaring rate, size, and density. At an air-flow rate of 6–8 m/s, turn 1 of the spiral separator had the ratio of the internal coil radius to the inner pipe diameter as r1/dpipe = 7.9; it was r1/dpipe = 7 on turn 2 and fell down to r1/dpipe = 6.25 on turn 3; for all subsequent turns, the ratio was r1/dpipe < 5. Under these conditions, the fraction reached 160 µm and included small high-protein flour fractions with a particle size of 17–20 µm. The percentage of product accumulated on turns 1, 2, and 3 was 80, 12, and 8%, respectively. The maximal product separation efficiency of the third drain system was as high as 98% at an input rate of 6 m/s. The maximal separation efficiency for premium flour reached 99.2% at an input rate of 4.2 m/s.
The separator proved efficient in classifying wheat grain flour into fractions as it was able to separate high-protein fraction and dispersed particles from the air flow. The separator could be used both as an independent device and as part of a complex technological scheme at the stage of pneumatic separators and unloaders.
791
Abstract
Microwave energy facilitates evaporation, thus producing more solids of higher quality than other concentration methods and traditional evaporators. Despite its effectiveness, the food industry has no methods for industrial microwave evaporation. This article introduces design and operating parameters for the working module of a novel microwave vacuum evaporation.
The new microwave vacuum evaporator with cylindrical modules was used for juice concentration. The fluid phase level was calculated based on the development and growth of vapor bubbles across the fluid phase volume. The steam phase level depended on the minimal volume of the steam separator.
When the operating pressure in the module was 7.4 kPa, the minimal radius of a vapor bubble was 5.6×10–5 m; 100% vapor content was observed 42 mm above the nucleation level of vapor bubbles. The average total height of the fluid phase level above the emitter was 26 mm, which exceeded the level of radiation penetration. The data obtained were used to develop an algorithm that made it possible to calculate the design and operating parameters of the microwave vacuum evaporator, as well as standard size modules with emitter powers of 600–3000 W. The modules with a diameter of 150 mm had the vapor zone at 43–8 mm and the transitional vapor-fluid zone at 9–16 mm. The boiling zone was at 45–60 mm.
The new microwave vacuum evaporator covered the entire power range of industrial air-cooled magnetrons. However, the final stage required modules of ≤ 1100 W for high concentrations of ≥ 60–80%.
850
Abstract
Nomad livestock farming is an extra raw material resource for regions with harsh climate. Foods based on meat of indigenous animals expand the range of products with high consumer properties. The quality and safety of meat products usually depend on the brine. The present research featured the effect of brine with Island moss (Cetrária islándica (L.) Ach.) on the sensory profile and microbiological safety of meat products.
The study involved meat of two-year-old indigenous cows, as well as multicomponent antibacterial and standard extrusion brines. The brine was injected with a syringe-injector with a hollow perforated needle at a 20 mm pitch. The tenderization took place in a universal express tenderizer with a rotation speed of 16 rpm and lasted for 10 h. The shelf-life was determined based the on microbiological, chemical, and sensory indicators.
By the end of the reserve shelf-life, the total microbial count was 1.2×103 CFU/g in the control and 1.0×103 CFU/g in the experimental sample. No opportunistic pathogenic bacteria or microorganisms were detected. No opportunistic pathogenic microorganisms were revealed when the microbiological parameters were studied in standard quantities and in quantities increased by an order of magnitude.
The changes in acid and peroxide numbers during storage indicated a stable oxidation of the fat component in the experimental sample. Its sensory evaluation exceeded the control sample by 0.9 points in terms color, texture, and smell. The meat marinated with C. islándica compiled with the quality standard and had a shelf-life which exceeded that of the traditionally-marinated meat by 5 days.
677
Abstract
Combination steam ovens, or combi steamers, have entered all spheres of food production, including the meat industry. Their rational use requires a scientific and practical foundation. This research featured the changes in mean volume temperature and temperature gradient that occur in meat products (one-dimensional bodies with different nutrient compositions) during heat treatment in dry air and a steam-air mix.
The research involved two samples of meat products with different moisture and fat contents. The chicken fillet sample had a moisture content of 74.5% and a fat content of 1.9% while the pork shoulder sample had a moisture content of 55.1% and a fat content of 29.4%. Shaped as a one-dimensional cylinder and a plate, the samples were subjected to heating at the temperature range of 160–240°C in a Unox-203G steam-convection oven (Italy). Dry air and a steam-air mix with a humidity of 80–85% served as a heating medium. The temperature was measured using thermocouples attached to a Sosna-004 meter.
The research revealed some patterns in the mean volume temperature and temperature gradient. The temperature gradient involved three stages during processing in a steam-air mix and four stages when treated with dry air. The change in the mean volume temperature for the steam-air mix could be described by a power law equation; the dry air treatment was described using a linear equation. When heated in dry air, the rate of change in the temperature gradient was constant at first but started to decrease at a certain stage. The change rate in the mean volume temperature remained low for 5 min and started to increase onwards, maintaining its value until the end of the process. When heated in a steam-air mix, the change rate in the temperature gradient dropped to its minimum in 4–5 min and started to grow. The mean volume temperature demonstrated a high change rate during the first 5 min and went down. The chicken fillet with its low fat content warmed up faster by 13–26% when processed in a steam-air mix and by 9–23% when treated in dry air. The plate-shaped products needed longer heat treatment. The composition and form had no significant effect on the nature of the change in the temperature gradient and mean volume temperature.
The obtained dependencies made it possible to select the optimal temperature and humidity conditions for convective frying of meat products.
691
Abstract
Effective bankruptcy risk diagnostics may prevent a financial crisis in Russia’s national economy. The article introduces a novel express tool for bankruptcy diagnostics based on early recognition of alert signs, crisis fields, and preliminary pre-crisis assessment. The tool is a selective-indicative model with regional and industrial specifications.
Regional and industrial exhibitors served as benchmark indicators. The empirical material included statistics, reference materials, and financial reports from agricultural organizations in the period of external economic shocks (2014–2022), Kemerovo region, Russia.
First, the alert signals of bankruptcy risk were identified based on 22 original methods of financial crisis forecasting. After that, they were assessed for practical popularity. The identified default risk signals were linked to the existing criteria of financial insolvency, subjected to economic interpretation, and classified. After fixing the analytical reference vectors, the authors identified the share of each indicator. By determining the latest results of model exponents, they ensured the direction of analytical reference vectors to maximize the disabled function. The next stage involved systematization and synthesis of alert signals into a diagnostic model to be developed into a gradation indicator. After fixing the signal analytical base, the model was tested to formulate conclusions about its adaptability in the current economy.
The resulting model relied on the share of each alert signal of bankruptcy risk in the rating number. It may improve the quality of predictive diagnostics. As the model needs few exponents, it provides a high-speed crisis analysis.
774
Abstract
Cherries (Prunus avium L.) are valued for their taste and nutritional properties. However, they are highly perishable. A low-temperature preservation technology can preserve cherries without spoiling their beneficial properties. This research experimentally substantiated the optimal methods and modes of freezing cherries, defined their refrigerated shelf-life, and identified varieties for low-temperature preservation.
The study featured cherries of eight varieties grown in the northern foothills of Dagestan. Fresh cherries served as control. Some cherries were frozen by immersion in a liquid solution of water, alcohol, and sugar (65:20:15) at –24°C. Others were frozen in bulk in air at –30, –33, and –35°C to be stored at –22°C for 3, 9, and 12 months. The nutritional profile was determined by standard methods of chemical analysis. The amount of juice lost during defrosting was assessed by the difference in weight before and after defrosting. The sensory evaluation involved a five-point scale.
The best nutritional profile belonged to the sample frozen in air at –35°C while the worst result was observed in the cherries frozen at –30°C. The cherries frozen in bulk in air at –33°C and those immersed in liquid coolant at –24°C demonstrated a poorer nutritional content (by 4.2–5.4%) than the sample frozen in air at –35°C. The sample frozen in air preserved 77.5–81.6% vitamin C, 83.7–89.0% pectin substances, 85.1–88.5% anthocyanins, and 81.4–86.4% sugar after 12 months of storage at –22°C. The sample frozen in liquid coolant retained 75.9–79.0% vitamin C, 84.4–88.2% pectin substances, 83.8–87.5% anthocyanins, and 80.3–84.7% sugar after 12 months of storage. The cherries of the Lezginka, Dagestanka, and Valery Chkalov varieties showed minimal changes after 12 months. The varieties of Buynakskaya, Krupnoplodnaya, and Polyanka could be recommended for nine-month storage. The varieties of Zhemchuzhnaya and Gudzon lost consumer attractiveness as early as after 3 months.
When frozen in bulk in air at –33°C and immersed in liquid coolant at –24°C, the cherries preserved their physicochemical properties after 3, 9, and 12 months of storage at –22°C. The study expanded the existing data about low-temperature preservation of cherries and their health benefits.