Volume 53, Issue 4, 2023
12395
Abstract
Micellar casein concentrate is a promising fractionation agent in skimmed milk production. It preserves the native structure of protein and changes the ratio of casein and whey proteins. Micellar casein concentrate reduces the consumption of raw materials, which makes it a promising component of milk-intensive protein foods. The research objective was to study the effect of micellar casein concentrate on rennin coagulation, cl ot dehydration, and cheese ripening.
The study featured skimmed milk, micellar casein concentrate, normalized mixes, and cheese samples of the Rossiiskii brand. The chemical composition and properties were studied by standar d methods.
The optimal ratio of casein and whey proteins was 95:5. It reduced the initial gelation time, facilitated casein micelles destabilization and subsequent flocculation, accelerated syneresis, and improved clot stability. The high protein mass content made it possible to halve the stirring and boiling time, as well as to increase the yield of the finished product by 15%. In the experimental cheese, the starter cultures growth had a longer lag phase while the exponential phase started on ripening day 30. The experimental sample also demonstrated a better starter microflora survival on day 60, which resulted in a better amino acid composition of the finished product.
In this research, micellar casein concentrate was able to affect rennet coagulation, clot dehydration, and ripening. Its application in the standard technology for the Rossiiskii cheese required the following adjustments: a longer starter activation, starter cultures with high proteolytic activity and ability to hydrolyze bitter peptides, extra rennet, a two-fold reduction of second heating and stirring, and at least 45 days or ripening.
The study featured skimmed milk, micellar casein concentrate, normalized mixes, and cheese samples of the Rossiiskii brand. The chemical composition and properties were studied by standar d methods.
The optimal ratio of casein and whey proteins was 95:5. It reduced the initial gelation time, facilitated casein micelles destabilization and subsequent flocculation, accelerated syneresis, and improved clot stability. The high protein mass content made it possible to halve the stirring and boiling time, as well as to increase the yield of the finished product by 15%. In the experimental cheese, the starter cultures growth had a longer lag phase while the exponential phase started on ripening day 30. The experimental sample also demonstrated a better starter microflora survival on day 60, which resulted in a better amino acid composition of the finished product.
In this research, micellar casein concentrate was able to affect rennet coagulation, clot dehydration, and ripening. Its application in the standard technology for the Rossiiskii cheese required the following adjustments: a longer starter activation, starter cultures with high proteolytic activity and ability to hydrolyze bitter peptides, extra rennet, a two-fold reduction of second heating and stirring, and at least 45 days or ripening.
321590
Abstract
The moose has good prospects for hunting and game breeding. Peripheral blood indicators can provide information about their health status and adaptive capabilities, as well as non-infectious, infectious, and invasive pathologies. Serum alkaline phosphatase activity is one of the most common clinical biochem ical tests in this respect.
The study involved blood samples obtained from male moose (n = 75) of four age groups: calves aged 6–7 months, young animals of 18 months old, adults of 2.5–7.5 years old, and adults aged ≥ 8.5 years. The biomaterial sampling was carried out in October – December in the southern taiga subzone, Kirov Region. The blood samples were obtained by cutting the jugular vein (Venae jugularis) immediately after the animal was shot during legal hunting. The blood serum tests involved a semi-automatic biochemical analyzer (Biochem SA High Technology, USA).
The alkaline phosphatase activity in male European moose during different periods of ontogenesis demonstrated the following pattern. In the first months of life, the enzyme activity was as high as 222.16 ± 31.14 U/L. This process was typical of intense hydrolysis of organic phosphorus esters, including the exchange of macroergs caused by rapid osteogenesis. At 18 months, the demand for organophosphorus compounds in metabolic processes decreased (46.48 ± 44.09 U/L), as did the role of the enzyme in maintaining homeostasis. In adults of 2.5–7.5 years old, alkaline phosphatase activity dropped to 69.88 ± 11.31 U/L. In 8.5-year-old males, it was as low as 47.34 ± 4.74 U/L. All age groups demonstrated significant differences in alkaline phosphatase activity. Therefore, age had a significant effect on enzyme activity. The study also revealed a certain correlation between alkaline phosphatase activity and body weight.
The dynamics of alkaline phosphatase activity in ontogenesis reflected homeostatic changes in the moose body. Indicators of alkaline phosphatase activity can serve as an efficiency marker and an additional criterion in standard selection methods in zootechnical practice.
The study involved blood samples obtained from male moose (n = 75) of four age groups: calves aged 6–7 months, young animals of 18 months old, adults of 2.5–7.5 years old, and adults aged ≥ 8.5 years. The biomaterial sampling was carried out in October – December in the southern taiga subzone, Kirov Region. The blood samples were obtained by cutting the jugular vein (Venae jugularis) immediately after the animal was shot during legal hunting. The blood serum tests involved a semi-automatic biochemical analyzer (Biochem SA High Technology, USA).
The alkaline phosphatase activity in male European moose during different periods of ontogenesis demonstrated the following pattern. In the first months of life, the enzyme activity was as high as 222.16 ± 31.14 U/L. This process was typical of intense hydrolysis of organic phosphorus esters, including the exchange of macroergs caused by rapid osteogenesis. At 18 months, the demand for organophosphorus compounds in metabolic processes decreased (46.48 ± 44.09 U/L), as did the role of the enzyme in maintaining homeostasis. In adults of 2.5–7.5 years old, alkaline phosphatase activity dropped to 69.88 ± 11.31 U/L. In 8.5-year-old males, it was as low as 47.34 ± 4.74 U/L. All age groups demonstrated significant differences in alkaline phosphatase activity. Therefore, age had a significant effect on enzyme activity. The study also revealed a certain correlation between alkaline phosphatase activity and body weight.
The dynamics of alkaline phosphatase activity in ontogenesis reflected homeostatic changes in the moose body. Indicators of alkaline phosphatase activity can serve as an efficiency marker and an additional criterion in standard selection methods in zootechnical practice.
2226
Abstract
Marine bivalves are rich in polyunsaturated fatty acids. Cerastoderma glaucum is a potentially commercial sea cockle that inhabits the Mediterranean and the Black Seas. This bivalve mollusk contains omega-3, omega-6, and omega-9 fatty acids. However, its lipid composition remains understudied. When determining total lipids, their classes, and fatty acid composition, standard methods often have to be adapted to the object in hand and tools available. The research objective was to develop a complex lipid analysis method for aquatic organisms.
The study featured total soft tissues of C. glaucum harvested from the pseudolittoral zone on the sand and silt soil of the Sevastopol coast of the Black Sea. The chromatographic methods made it possible to identify total lipids and classify them into phospholipids, monoglycerides, diglycerides, sterols, and triacylglycerols. The subsequent densimetric determination involved a flatbed scanner and the TLC Manager 4.0.2.3D software. The fatty acid composition for total lipids was studied using the chromatography-mass spectrometric method.
The existing methods in lipidology were adapted for determining total lipids, their classes, and the fatty acid composition of total lipids in C. glaucum. The article introduces a detailed description of the method for determining total lipids, as well as of how to prepare equipment and reagents to classify common lipids using multidimensional thin layer chromatography. It also contains an authentic scheme of chromatographic baths for stepwise separation, densitometric measurements, and examples of fatty acid chromatograms and mass spectra. The new sample preparation method for determining fatty acids in total lipids by gas chromatography demonstrated a minimal loss in native structure and proved to be less aggressive than standard methods of sample derivatization.
The new method for lipid analysis of clam tissues appeared to be economical, less time-consuming, and reagent-intensive. It can be recommended for small laboratories engaged in bioenergetics or comparative analyzes of aquatic organisms.
The study featured total soft tissues of C. glaucum harvested from the pseudolittoral zone on the sand and silt soil of the Sevastopol coast of the Black Sea. The chromatographic methods made it possible to identify total lipids and classify them into phospholipids, monoglycerides, diglycerides, sterols, and triacylglycerols. The subsequent densimetric determination involved a flatbed scanner and the TLC Manager 4.0.2.3D software. The fatty acid composition for total lipids was studied using the chromatography-mass spectrometric method.
The existing methods in lipidology were adapted for determining total lipids, their classes, and the fatty acid composition of total lipids in C. glaucum. The article introduces a detailed description of the method for determining total lipids, as well as of how to prepare equipment and reagents to classify common lipids using multidimensional thin layer chromatography. It also contains an authentic scheme of chromatographic baths for stepwise separation, densitometric measurements, and examples of fatty acid chromatograms and mass spectra. The new sample preparation method for determining fatty acids in total lipids by gas chromatography demonstrated a minimal loss in native structure and proved to be less aggressive than standard methods of sample derivatization.
The new method for lipid analysis of clam tissues appeared to be economical, less time-consuming, and reagent-intensive. It can be recommended for small laboratories engaged in bioenergetics or comparative analyzes of aquatic organisms.
4409
Abstract
Eukaryotic probiotics currently attract a lot of scientific attention, with Saccharomyces cerevisiae and Saccharomyces boulardii being the most widely investigated probiotic yeasts. The range of yeast species with probiotic potential needs to be broadened. In this respect, juice-providing plants may diversify eukaryoti c probiotic sources for organism preference.
This study tested the probiotic potential of Pichia kudriavzevii and Kluyveromyces marxianus isolated from coconut juice and Schizosaccharomyces pombe and Wickherhamomyces anomalus isolated from raffia palm juice in Nigeria. The in vitro tests used the optical density method to assay the tolerance to acid (pH 2, 3, 5), alkaline (pH 7.5, 8.0), gastric juice (30%), bile (1, 2, and 3%), and osmotic pressure (5, 10, 15, 20, 25, and 30% gluco se solution).
All four yeasts survived in the test environments, exhibiting varying degrees of probiotic potential. After 96 h in simulated gastric juice, S. pombe outperformed K. marxianus and W. anomalus by 13 and 97.7% (p < 0.05), respectively. W. anomalus appeared to be the least viable in 30% gastric juice. After 96 h in the acid media, all yeasts performed better at pH 3.0 than at pH 2.0, with roughly 89% (1.695/0.185 mean absorbance values) greater growth in pH 3.0 than in pH 2.0. The alkaline media had a better effect on the growth rate. P. kudriavzevii fared best at pH 2.0 and 3.0 for up to 96 h. All yeasts maintained viability in 1, 2, and 3% bile solutions, although the growth rate did not improve significantly in any of the assay periods. Only minimal growth increase was registered in increased bile concentrations. All samples demonstrated sustained viability in 5–30% glucose between 24 and 48 h of incubation. After 48 h of incubation, the yeast concentrations began to fall as the glucose concentration rose from 5 to 30%. P. kudriavzevii was the least affected after 96 h (41.8%) and demonstrated the best survival results by the four criteria tested in this study.
If this species meets all other non-assayed parameters which qualify a microorganism as a probiotic, P. kudriavzevii obtained from Nigerian coconut juice can be recommended as a potential s ource of commercial probiotics.
This study tested the probiotic potential of Pichia kudriavzevii and Kluyveromyces marxianus isolated from coconut juice and Schizosaccharomyces pombe and Wickherhamomyces anomalus isolated from raffia palm juice in Nigeria. The in vitro tests used the optical density method to assay the tolerance to acid (pH 2, 3, 5), alkaline (pH 7.5, 8.0), gastric juice (30%), bile (1, 2, and 3%), and osmotic pressure (5, 10, 15, 20, 25, and 30% gluco se solution).
All four yeasts survived in the test environments, exhibiting varying degrees of probiotic potential. After 96 h in simulated gastric juice, S. pombe outperformed K. marxianus and W. anomalus by 13 and 97.7% (p < 0.05), respectively. W. anomalus appeared to be the least viable in 30% gastric juice. After 96 h in the acid media, all yeasts performed better at pH 3.0 than at pH 2.0, with roughly 89% (1.695/0.185 mean absorbance values) greater growth in pH 3.0 than in pH 2.0. The alkaline media had a better effect on the growth rate. P. kudriavzevii fared best at pH 2.0 and 3.0 for up to 96 h. All yeasts maintained viability in 1, 2, and 3% bile solutions, although the growth rate did not improve significantly in any of the assay periods. Only minimal growth increase was registered in increased bile concentrations. All samples demonstrated sustained viability in 5–30% glucose between 24 and 48 h of incubation. After 48 h of incubation, the yeast concentrations began to fall as the glucose concentration rose from 5 to 30%. P. kudriavzevii was the least affected after 96 h (41.8%) and demonstrated the best survival results by the four criteria tested in this study.
If this species meets all other non-assayed parameters which qualify a microorganism as a probiotic, P. kudriavzevii obtained from Nigerian coconut juice can be recommended as a potential s ource of commercial probiotics.
3217
Abstract
Numerous adverse factors may violate the human immune system and trigger various diseases. Immune-response modulating agents, or immunomodulators, help the immune system to function properly. Biologically active substances extracted from medicinal plants are especially promising in this respect. The article reviews traditional and novel methods for extracting biologically active immune-response modulating agents from plant raw materials.
The review covered articles published in English and Russian in 2019–2023 and indexed in Scopus, Web of Science, and eLIBRARY.
Extraction efficiency depends on such factors as solvent, temperature, and particle size, but the method is the most important one. Traditional extraction methods include percolation, maceration, Soxhlet extraction, heat reflux extraction, and decoction. However, they are solvent-consuming and expensive. Modern extraction methods rely on carbon dioxide, microwave treatment, ultrasonic processing, and pressure. They proved quite efficient in extracting biologically active substances from ginseng (Panax ginseng). Carbon dioxide, or supercritical, extraction was able to isolate polyphenol quercetin from quince fruit (Cydonia oblonga) and other biologically active substances from alfalfa (Medicago sativa). Maceration with methanol was applied to meadowsweet (Filipendula ulmaria) while Soxhlet extraction proved especially effective with smoke tree (Cotinus coggygria), moorland spotted orchid (Dactylorhiza maculata), and greater butterfly-orchid (Platanthera chlorantha).
Both traditional and novel extraction methods find their application in medicine and food science, where they yield plant extracts of biologically active immune-response modulating agents.
The review covered articles published in English and Russian in 2019–2023 and indexed in Scopus, Web of Science, and eLIBRARY.
Extraction efficiency depends on such factors as solvent, temperature, and particle size, but the method is the most important one. Traditional extraction methods include percolation, maceration, Soxhlet extraction, heat reflux extraction, and decoction. However, they are solvent-consuming and expensive. Modern extraction methods rely on carbon dioxide, microwave treatment, ultrasonic processing, and pressure. They proved quite efficient in extracting biologically active substances from ginseng (Panax ginseng). Carbon dioxide, or supercritical, extraction was able to isolate polyphenol quercetin from quince fruit (Cydonia oblonga) and other biologically active substances from alfalfa (Medicago sativa). Maceration with methanol was applied to meadowsweet (Filipendula ulmaria) while Soxhlet extraction proved especially effective with smoke tree (Cotinus coggygria), moorland spotted orchid (Dactylorhiza maculata), and greater butterfly-orchid (Platanthera chlorantha).
Both traditional and novel extraction methods find their application in medicine and food science, where they yield plant extracts of biologically active immune-response modulating agents.
1953
Abstract
Global food shortages make it necessary to look for alternative renewable bioresources. In the south of Western Siberia, the filamentous cyanoprokaryote Limnospira fusiformis triggers seasonal algae bloom in hypergaline alkaline Lake Solenoye. The species has valuable nutritional properties, and its phytomass is a potential source of proteins and biologically active substances. The O9.13F strain of L. fusiformis has a good potential as a bioadditive in animal feeding. The article offers a technology for cultivating O9.13F of L. fusiformis, isolated from Lake Solenoye. The research objectives were to establish the optimal cultivation conditions, medium, and periodicity.
The study featured strain O9.13F of filamentous cyanoprokaryote L. fusiformis. The micropipette method made it possible to isolate pure culture from water samples taken from Lake Solenoye, Omsk, Russia, at the end of algae bloom. The cultivation involved a UT-6070 climatic chamber under uniform illumination with light intensity 10–30 μmol photons/m2s and 12-h light-dark circle at 20 ± 2°C on various media: natural habitat – water from the Solenoye Lake; mineral medium – liquid Zarrouk’s medium; agarized Zarrouk’s medium; composite variants, where the ratio of mineral medium vs. water varied from 1:9 to 9:1.
Lake water inhibited the culture growth: the trichomes died and sank on day 10–15. Zarrouk’s agarized medium stopped the culture growth as early as on day 2. The most intensive growth and development of the culture was observed in the samples with Zarrouk’s mineral liquid medium and a composite mix of Zarrouk’s medium and sterilized water at a ratio of 5:5. Without stirring, full-fledged trichomes had no time to develop, and the increase in phytomass volume slowed down. O9.13F showed the highest rate of phytomass growth at a cultivation temperature of 20 ± 2°C and a light intensity of 10–30 μmol photons/m2s. The recommended light-dark circle was12:12 h. Zarrouk’s mineral liquid medium and a composite medium of Zarrouk’s medium and sterilized water proved to be optimal in a UT-6070 environmental chamber. Europolitext KV-06 or mechanical mixing could prevent sedimentation of phosphates after 20 days of cultivation. The optimal recultivation frequency was once every 5–7 days.
The new cultivation technology made it possible to obtain a significant volume of L. fusiformis phytomass in a short time and with low financial expenses.
The study featured strain O9.13F of filamentous cyanoprokaryote L. fusiformis. The micropipette method made it possible to isolate pure culture from water samples taken from Lake Solenoye, Omsk, Russia, at the end of algae bloom. The cultivation involved a UT-6070 climatic chamber under uniform illumination with light intensity 10–30 μmol photons/m2s and 12-h light-dark circle at 20 ± 2°C on various media: natural habitat – water from the Solenoye Lake; mineral medium – liquid Zarrouk’s medium; agarized Zarrouk’s medium; composite variants, where the ratio of mineral medium vs. water varied from 1:9 to 9:1.
Lake water inhibited the culture growth: the trichomes died and sank on day 10–15. Zarrouk’s agarized medium stopped the culture growth as early as on day 2. The most intensive growth and development of the culture was observed in the samples with Zarrouk’s mineral liquid medium and a composite mix of Zarrouk’s medium and sterilized water at a ratio of 5:5. Without stirring, full-fledged trichomes had no time to develop, and the increase in phytomass volume slowed down. O9.13F showed the highest rate of phytomass growth at a cultivation temperature of 20 ± 2°C and a light intensity of 10–30 μmol photons/m2s. The recommended light-dark circle was12:12 h. Zarrouk’s mineral liquid medium and a composite medium of Zarrouk’s medium and sterilized water proved to be optimal in a UT-6070 environmental chamber. Europolitext KV-06 or mechanical mixing could prevent sedimentation of phosphates after 20 days of cultivation. The optimal recultivation frequency was once every 5–7 days.
The new cultivation technology made it possible to obtain a significant volume of L. fusiformis phytomass in a short time and with low financial expenses.
2691
Abstract
A profitable meat-processing business relies on the rational use of its resources, which, in its turn, depends on the constant improvement of product formulations and development of new ones. These operations involve advanced analytical methods and complex approaches. The article introduces a review of modern technical solutions, methods, and approaches to modeling new complex meat products with preset quality indicators.
The review (1990–2022) involved research articles published in high-rated peer-reviewed research journals, educational literature, digital theses published by Russian Dissertation Councils, and patents registered by the Institute of Industrial Property.
The synchronic and diachronic analysis of basic principles of food product design and parametric modeling revealed no universal methodology for meat products development, both in terms of goals and applicability to different meat products types. Forecasting of finished meat products quality indicators requires relevant and accurate information, which is highly variable and fast-changing. Unfortunately, advanced information technologies are slow to adapt to the urgent tasks of the food industry.
As a result, the current methods for developing new complex meat product formulations are useless when meat producers have no access to relevant and self-updating databases on raw m aterials properties.
The review (1990–2022) involved research articles published in high-rated peer-reviewed research journals, educational literature, digital theses published by Russian Dissertation Councils, and patents registered by the Institute of Industrial Property.
The synchronic and diachronic analysis of basic principles of food product design and parametric modeling revealed no universal methodology for meat products development, both in terms of goals and applicability to different meat products types. Forecasting of finished meat products quality indicators requires relevant and accurate information, which is highly variable and fast-changing. Unfortunately, advanced information technologies are slow to adapt to the urgent tasks of the food industry.
As a result, the current methods for developing new complex meat product formulations are useless when meat producers have no access to relevant and self-updating databases on raw m aterials properties.
337578
Abstract
Antibiotics have long been overused for non-therapeutic purposes. As a result, Escherichia, Enterobacter, Klebsiella, and Proteus in avian microbiomes have become reservoirs for genetic determinants of resistance, thus spreading resistance to antibiotics and contaminating raw materials and finished products. The food industry is looking for alternative means to preserve health and maintain high productivity of commercial poultry, e.g., probiotics, phytobiotics, organic acids, etc. The research featured the effect of antibiotics and phytobiotics on enteropathogenic bacteria in the microbiomes of broiler chicken.
Escherichia coli bacteria were cultivated in vitro in subthreshold concentrations on nutrient media with antibiotics for 37 days to study the effect of low doses of antibiotics on the sensitivity of isolates. The study involved microbiocenoses of broiler chicken that received avilamycin A and a phytobiotic based on Brassica juncea, Linum usitatissimum, and Nigella sativa L. A set of experiments covered the species composition of opportunistic Enterobacteriaceae, the phenotypic sensitivity to antibiotics, and the genetic determinants of resistance, as well as the antimicrobial potential of phytobiotics.
E. coli developed no resistance for 37 days when the antibiotic dose remained below minimal inhibitory. Opportunistic gram-negative Enterobacterales predominated in all litter samples. E. coli, Klebsiella pneumoniae, and Proteus mirabilis accounted for more than 30% of all isolated strains. Avilamycin A and the phytobiotic affected the coccal microflora but had no effect on the genus-species composition of Enterobacteriaceae. Litter samples from both experimental and control groups demonstrated K. pneumoniae with severe phenotypic resistance to ciprofloxacin, as well as blaDHA genes. In broiler farming, maintenance and circulation of resistance agents depends on litter microbiota. In this research, the chicken that received the phytobiotic showed the lowest level of resistance to ciprofloxacin while the groups that received avilamycin A had the highest resistance results.
During a broiler’s life span, bacteria with no active resistance determinants in their genome remained sensitive to antibiotics, even though the contact with the latter was constant. Phytobiotics showed good prospects for broiler farming as food additive that could reduce and eventually eliminate the intake of antibiotics.
Escherichia coli bacteria were cultivated in vitro in subthreshold concentrations on nutrient media with antibiotics for 37 days to study the effect of low doses of antibiotics on the sensitivity of isolates. The study involved microbiocenoses of broiler chicken that received avilamycin A and a phytobiotic based on Brassica juncea, Linum usitatissimum, and Nigella sativa L. A set of experiments covered the species composition of opportunistic Enterobacteriaceae, the phenotypic sensitivity to antibiotics, and the genetic determinants of resistance, as well as the antimicrobial potential of phytobiotics.
E. coli developed no resistance for 37 days when the antibiotic dose remained below minimal inhibitory. Opportunistic gram-negative Enterobacterales predominated in all litter samples. E. coli, Klebsiella pneumoniae, and Proteus mirabilis accounted for more than 30% of all isolated strains. Avilamycin A and the phytobiotic affected the coccal microflora but had no effect on the genus-species composition of Enterobacteriaceae. Litter samples from both experimental and control groups demonstrated K. pneumoniae with severe phenotypic resistance to ciprofloxacin, as well as blaDHA genes. In broiler farming, maintenance and circulation of resistance agents depends on litter microbiota. In this research, the chicken that received the phytobiotic showed the lowest level of resistance to ciprofloxacin while the groups that received avilamycin A had the highest resistance results.
During a broiler’s life span, bacteria with no active resistance determinants in their genome remained sensitive to antibiotics, even though the contact with the latter was constant. Phytobiotics showed good prospects for broiler farming as food additive that could reduce and eventually eliminate the intake of antibiotics.
163616
Abstract
The article discusses the dairy industry in the Chuvash Republic, Russia. The Russian Federation is experiencing a shortage of milk. Currently, the per capita milk consumption in the country is by more than a quarter behind the rational intake recommended by the Ministry of Health, which is 325 kg. However, the Chuvash Republic boasts 373 kg of per capita milk production, which is by 71% higher than the average data for the rest of the country, and the high quality of Chuvash milk is unanimously confirmed by leading domestic experts. The authors analyzed the success factors of milk production in the Chuvash Republic to be extrapolated on the entire domestic industry.
The research relied on such demographic data as the ratio of urban vs. rural population; dairy herd data, e.g., livestock population, farm types, dairy productivity, etc.; dairy production and processing business data. The methods included systematization, generalization, grouping, statistical data processing, and analysis of temporal dynamics indicators.
The Chuvash Republic has a large percentage of rural population and a lot of subsidiary dairy farms: 22 000 farms own more than 60% of dairy cows in the region and provide 55% of milk processing volumes. Subsidies allocated by the local government allow farm owners to ensure the high dairy productivity of cows. Most of the milk in the Chuvash Republic can be classified as near-organic. Leading regional milk producers have their own agricultural lands to provide environmentally friendly feed, as well as specialized premises for herd keeping and milking, retail outlets to sell their products, etc. A third of enterprises maintain the milk productivity at 7800–9200 kg, which is as high as in Denmark, the Netherlands, Great Britain, and Germany. Most Chuvash dairy farmers owe their high results to the state support funds allocated for the purchase of breeding cattle. The twelve largest milk producers in the region provide 100% of the output of drinking milk, so private farms mainly focus on meeting the needs of dairy processing enterprises. The latter also receive seasonal subsidies.
The Chuvash milk miracle can be explained by the following factors: big rural population; private subsidiary farms; high-quality breeding dairy livestock; high-quality feed; good milk production and processing equipment. However, the comprehensive system of state support measures remains the most important success factor.
The research relied on such demographic data as the ratio of urban vs. rural population; dairy herd data, e.g., livestock population, farm types, dairy productivity, etc.; dairy production and processing business data. The methods included systematization, generalization, grouping, statistical data processing, and analysis of temporal dynamics indicators.
The Chuvash Republic has a large percentage of rural population and a lot of subsidiary dairy farms: 22 000 farms own more than 60% of dairy cows in the region and provide 55% of milk processing volumes. Subsidies allocated by the local government allow farm owners to ensure the high dairy productivity of cows. Most of the milk in the Chuvash Republic can be classified as near-organic. Leading regional milk producers have their own agricultural lands to provide environmentally friendly feed, as well as specialized premises for herd keeping and milking, retail outlets to sell their products, etc. A third of enterprises maintain the milk productivity at 7800–9200 kg, which is as high as in Denmark, the Netherlands, Great Britain, and Germany. Most Chuvash dairy farmers owe their high results to the state support funds allocated for the purchase of breeding cattle. The twelve largest milk producers in the region provide 100% of the output of drinking milk, so private farms mainly focus on meeting the needs of dairy processing enterprises. The latter also receive seasonal subsidies.
The Chuvash milk miracle can be explained by the following factors: big rural population; private subsidiary farms; high-quality breeding dairy livestock; high-quality feed; good milk production and processing equipment. However, the comprehensive system of state support measures remains the most important success factor.
2518
Abstract
The slowest heating zone tends to move about in food systems with convective and predominantly convective heat transfer. If the thermocouple follows the movement, the process lethality differs from the value precalculated for a fixed thermocouple location. Hence, the heat treatment modes depend on the movement of the slowest heating zone, which should be taken into account before planning food system processes. This research aimed at identifying a statistically significant difference between lethality for fixed and moving slowest heating zones in various food systems.
The study involved four homophasic and heterophasic model food systems. Food System 1 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of aqueous solution with 1.5% sucrose and 1.5% NaCl. Food System 2 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of 11% aqueous sucrose solution. Food System 3 was represented by homophase reconstituted clarified baby-food apple juice with 11.2% soluble solids. Food System 4 was a heterophase model system, represented by reconstituted baby-food apple juice with pulp and 11.2% soluble solids with a dispersed phase involved in convection. The temperature changes were monitored using the E-ValPro multichannel system and the SSA-TS model temperature sensors. The temperature sensors were fixed inside the jar with the food system.
Food System 1 showed no significant differences in lethality. Other model systems had sterilization temperature intervals when the difference in lethality was statistically significant. However, this difference was very small for Food Systems 2 and 3. The largest difference belonged to Food System 4, where the dispersed phase was involved in the convective flow.
In this research, a statistically significant difference in lethality for fixed and moving slowest heating zones occurred only in heterophase food systems with convective and predominantly convective heat exchange, where the dispersed phase was involved in the convection flow. This fact must be taken into account when identifying heat treatment modes for such food systems.
The study involved four homophasic and heterophasic model food systems. Food System 1 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of aqueous solution with 1.5% sucrose and 1.5% NaCl. Food System 2 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of 11% aqueous sucrose solution. Food System 3 was represented by homophase reconstituted clarified baby-food apple juice with 11.2% soluble solids. Food System 4 was a heterophase model system, represented by reconstituted baby-food apple juice with pulp and 11.2% soluble solids with a dispersed phase involved in convection. The temperature changes were monitored using the E-ValPro multichannel system and the SSA-TS model temperature sensors. The temperature sensors were fixed inside the jar with the food system.
Food System 1 showed no significant differences in lethality. Other model systems had sterilization temperature intervals when the difference in lethality was statistically significant. However, this difference was very small for Food Systems 2 and 3. The largest difference belonged to Food System 4, where the dispersed phase was involved in the convective flow.
In this research, a statistically significant difference in lethality for fixed and moving slowest heating zones occurred only in heterophase food systems with convective and predominantly convective heat exchange, where the dispersed phase was involved in the convection flow. This fact must be taken into account when identifying heat treatment modes for such food systems.
2746
Abstract
To select an optimal mode of evaporation and crystallization, sugar producers need comprehensive databases of chemical and thermodynamic properties of sucrose solutions. This article introduces refined experimental estimates of the chemical and thermodynamic properties of pure and technical multicomponent sucrose solutions.
The study involved a modernized ebulliometer with two circulation tubes that measured the true boiling points of concentrated and supersaturated homogeneous solutions, as well as heterogeneous crystallizing systems. The boiling points of pure and multicomponent sucrose solutions were observed for the following variables: 5–93% dry solids, 60–100% purity, 20–100 kPa.
In this study, the sucrose solutions did not obey Raoult’s laws for ideal mixtures, while the Ramsay-Young’s equation and Dühring’s rule were approximate. The thermodynamic properties of these solutions fit in the Lewis theory of activity. The study yielded a new thermodynamic equation for the boiling point in pure and technical multicomponent sucrose solutions. The authors revealed the correlation between the constants of Ramsay-Young and Dühring and the concentration and supersaturation of sucrose solutions, as well as the change in the entropy of these solutions. The error of estimate was 2–3%. The supersaturation coefficient was measured by the ratio of the boiling points of the solution and water.
The authors used differential and relative ebulliometric criteria to develop some practical methods for monitoring and controlling the process of isobaric evaporative crystallization. The new method can improve the commercial mass sucrose crystallization from boiling solutions.
The study involved a modernized ebulliometer with two circulation tubes that measured the true boiling points of concentrated and supersaturated homogeneous solutions, as well as heterogeneous crystallizing systems. The boiling points of pure and multicomponent sucrose solutions were observed for the following variables: 5–93% dry solids, 60–100% purity, 20–100 kPa.
In this study, the sucrose solutions did not obey Raoult’s laws for ideal mixtures, while the Ramsay-Young’s equation and Dühring’s rule were approximate. The thermodynamic properties of these solutions fit in the Lewis theory of activity. The study yielded a new thermodynamic equation for the boiling point in pure and technical multicomponent sucrose solutions. The authors revealed the correlation between the constants of Ramsay-Young and Dühring and the concentration and supersaturation of sucrose solutions, as well as the change in the entropy of these solutions. The error of estimate was 2–3%. The supersaturation coefficient was measured by the ratio of the boiling points of the solution and water.
The authors used differential and relative ebulliometric criteria to develop some practical methods for monitoring and controlling the process of isobaric evaporative crystallization. The new method can improve the commercial mass sucrose crystallization from boiling solutions.
3099
Abstract
Polyphenols are potential neuroprotectors that increase lifespan and slow down aging. Red clover (Trifolium pratense L.) is a promising source of biologically active substances. Its extracts contain biochanin A and chlorogenic acid. This research used Caenorhabditis elegans to study the effect of polyphenols extracted from red clover callus cultures on SOD-3 and HSP-16.2 genes, as well as their anti-amyloid potential.
The chlorogenic acid and biochanin A (200, 100, 50, and 10 µM) with a purity of 95% were isolated from callus extracts of T. pratense L. The effect of polyphenols on SOD-3 and HSP-16.2 was assessed after 5 and 2 h of heat stress (35°C), respectively, using C. elegans N2 Bristol as model organism. The neuroprotective potential was measured by counting paralyzed nematodes after 18, 40, and 62 h of incubation.
The research established a dose-dependent effect between the concentration of biologically active substances and the percentage of paralyzed nematodes after 18 h of cultivation. The lowest paralysis phenotype count occurred at a concentration of 200 μM. The activity of 200 μM biochnin A was 1.18 times as high as that of a 200 μM chlorogenic acid solution. Biochanin A solutions increased SOD-3 expression by 3.7 times, compared to the control.
The biologically active substances exhibited relative neuroprotective activity and affected the expression of antioxidant defense gene in C. elegans.
The chlorogenic acid and biochanin A (200, 100, 50, and 10 µM) with a purity of 95% were isolated from callus extracts of T. pratense L. The effect of polyphenols on SOD-3 and HSP-16.2 was assessed after 5 and 2 h of heat stress (35°C), respectively, using C. elegans N2 Bristol as model organism. The neuroprotective potential was measured by counting paralyzed nematodes after 18, 40, and 62 h of incubation.
The research established a dose-dependent effect between the concentration of biologically active substances and the percentage of paralyzed nematodes after 18 h of cultivation. The lowest paralysis phenotype count occurred at a concentration of 200 μM. The activity of 200 μM biochnin A was 1.18 times as high as that of a 200 μM chlorogenic acid solution. Biochanin A solutions increased SOD-3 expression by 3.7 times, compared to the control.
The biologically active substances exhibited relative neuroprotective activity and affected the expression of antioxidant defense gene in C. elegans.
2013
Abstract
Tomato (Solanum lycopersicum L.) is one of the most important crops that is extensively used in the food processing industry. During tomato processing, abundant by-products such as skins, pulps, seeds, and waste are generated and cause environmental burdens. To solve this problem, tomato pomace was subsequently used as a material for making tomato sauce. However, it is essential that the production of tomato ketchup meets the required standards. Therefore, it is important to analyze the physicochemical and sensory characteristics of the product. We aimed to study the effect of corn starch addition on the physicochemical and sensory properties of tomato ketchup made from tomato waste and to assess the acceptability of tomato sauce formulated with different concentrations of corn starch.
Tomato ketchup was cooked at 90°C for 15 min and then hot-filled into a sterile glass bottle. It was then analyzed for physical properties (color, viscosity, and total dissolved solids), chemical properties (pH, titratable acidity, moisture content), microbiological quality (total bacteria, mold, and yeast), and sensory acceptance.
The results showed that corn starch influenced the color characteristics of the tomato sauce. Adding more than 4% of corn starch increased the viscosity and total solids content significantly (p < 0.05). Also, corn starch addition decreased the water content and acidity, as well as increased the pH of the tomato sauce. Microbiological analysis showed no growth of bacteria, mold, or yeast in any of the test samples. According to sensory analysis, the tomato sauce with 1% of corn starch had the highest acceptance, while higher concentrations of corn starch decreased the texture acceptance.
Our findings may indicate that, with proper formulation, tomato by-products can be used as raw materials to develop sustainable alternative value-added products that consumers accept organoleptically. Further investigations can be conducted in the pilot-scale studies to enhance the feasibility of tomato pomace ketchup as a commercial product.
Tomato ketchup was cooked at 90°C for 15 min and then hot-filled into a sterile glass bottle. It was then analyzed for physical properties (color, viscosity, and total dissolved solids), chemical properties (pH, titratable acidity, moisture content), microbiological quality (total bacteria, mold, and yeast), and sensory acceptance.
The results showed that corn starch influenced the color characteristics of the tomato sauce. Adding more than 4% of corn starch increased the viscosity and total solids content significantly (p < 0.05). Also, corn starch addition decreased the water content and acidity, as well as increased the pH of the tomato sauce. Microbiological analysis showed no growth of bacteria, mold, or yeast in any of the test samples. According to sensory analysis, the tomato sauce with 1% of corn starch had the highest acceptance, while higher concentrations of corn starch decreased the texture acceptance.
Our findings may indicate that, with proper formulation, tomato by-products can be used as raw materials to develop sustainable alternative value-added products that consumers accept organoleptically. Further investigations can be conducted in the pilot-scale studies to enhance the feasibility of tomato pomace ketchup as a commercial product.
2294
Abstract
Natural food additives can fortify meat products. Bee pollen, also known as beebread or ambrosia, contains amino acids, carbohydrates, vitamins, minerals, enzymes, etc. As a result, it possesses numerous therapeutic and prophylactic properties. Bee pollen has good prospects as a fortifying agent for jerky meat, i.e., lean and dehydrated trimmed meat cut into strips. This study tested dry-cured jerky meat fortified with bee pollen on rats with carbon tetrachloride-induced acute toxic hepatitis.
The research featured white non-linear laboratory rats. The control group obtained a standard diet. The experimental rats were induced with liver hepatitis by administering CCl4. On day 2, the experimental group was divided into three subgroups: experimental group I (standard diet + traditional jerky), experimental group II (standard diet + jerky fortified with bee pollen), and experimental group III (standard diet), which served as positive control. The research involved a MicroCC20Vet analyzer for hematological tests and a StatFax 3300 analyzer with Diacon DS diagnostic systems for biochemical tests. The histological analyses relied on the method developed by G.A. Merkulov.
The hematological parameters demonstrated no changes. As for the biochemistry, experimental groups I and II developed a protein content increase. On day 14, the concentration of protein and its fractions in experimental group II reached the level of intact animals. In experimental groups II and III, the total protein was significantly higher due to the globulin fraction as a result of inflammatory and destructive processes in the liver. However, the rats had normal live weight gain, and their liver demonstrated no histological deviations.
In this preclinical study, bee pollen as part of jerky meat formulation had no negative effect on laboratory rats. Bee pollen also proved its antioxidant properties.
The research featured white non-linear laboratory rats. The control group obtained a standard diet. The experimental rats were induced with liver hepatitis by administering CCl4. On day 2, the experimental group was divided into three subgroups: experimental group I (standard diet + traditional jerky), experimental group II (standard diet + jerky fortified with bee pollen), and experimental group III (standard diet), which served as positive control. The research involved a MicroCC20Vet analyzer for hematological tests and a StatFax 3300 analyzer with Diacon DS diagnostic systems for biochemical tests. The histological analyses relied on the method developed by G.A. Merkulov.
The hematological parameters demonstrated no changes. As for the biochemistry, experimental groups I and II developed a protein content increase. On day 14, the concentration of protein and its fractions in experimental group II reached the level of intact animals. In experimental groups II and III, the total protein was significantly higher due to the globulin fraction as a result of inflammatory and destructive processes in the liver. However, the rats had normal live weight gain, and their liver demonstrated no histological deviations.
In this preclinical study, bee pollen as part of jerky meat formulation had no negative effect on laboratory rats. Bee pollen also proved its antioxidant properties.
3241
Abstract
Russian cuisine reflects the identity of its peoples. However, modern nutrition tends to level the multicultural peculiarities of Russian cuisine. This research objective was to identify the effect of packaging and storage time on the quality profile of instant turnip and rutabaga porridges.
The study featured quality indicators of food concentrates. Samples of instant porridges were packaged in sachet bags and cups made of complex materials. They were stored at a 20–25°C and a relative humidity of ≤75% for 8 months. The sensory, physicochemical, and microbiological variables were measured using standard research methods.
After 6 and 8 months of storage, the total sensory assessment for the porridge cups was higher by 1.0 and 2.0 points, respectively, than for the porridge sachets. The cups did not affect the moisture and fat content during storage. The recoverability of the cupped samples was higher by 10.9 and 14.2% after 6 and 8 months of storage, respectively. The mesophilic aerobic and facultative anaerobic microbial count for porridge cups fell by 11.0 times after 6 months of storage and by 3.2 times after 8 months of storage, compared to the sachets. The tests revealed no yeast, mold, Bacillus cereus, coliform bacteria, or pathogenic microorganisms.
Shelf-life had a greater effect on quality profile of instant porridge than packaging. In this research, the recommended shelf life for instant turnip and rutabaga porridges was 6 months. The effect of other packaging types and materials on food concentrates is a promising research direction.
The study featured quality indicators of food concentrates. Samples of instant porridges were packaged in sachet bags and cups made of complex materials. They were stored at a 20–25°C and a relative humidity of ≤75% for 8 months. The sensory, physicochemical, and microbiological variables were measured using standard research methods.
After 6 and 8 months of storage, the total sensory assessment for the porridge cups was higher by 1.0 and 2.0 points, respectively, than for the porridge sachets. The cups did not affect the moisture and fat content during storage. The recoverability of the cupped samples was higher by 10.9 and 14.2% after 6 and 8 months of storage, respectively. The mesophilic aerobic and facultative anaerobic microbial count for porridge cups fell by 11.0 times after 6 months of storage and by 3.2 times after 8 months of storage, compared to the sachets. The tests revealed no yeast, mold, Bacillus cereus, coliform bacteria, or pathogenic microorganisms.
Shelf-life had a greater effect on quality profile of instant porridge than packaging. In this research, the recommended shelf life for instant turnip and rutabaga porridges was 6 months. The effect of other packaging types and materials on food concentrates is a promising research direction.
2128
Abstract
Distilled alcoholic drinks are popular all over the world. Monitoring the quality and safety of such drinks requires modern instrumental methods. Chemical composition of alcoholic beverages has become focus of numerous experimental and theoretical publications. However, this area remains understudied. This research provided an experimental confirmation of the capillary electrophoresis as a prospective method for determining anions in alcoholic beverages.
The study involved model solutions and 30 samples of distilled alcoholic beverages purchased by random sampling from a retail chain. The chemical analysis relied on a PrinCE 560 capillary electrophoresis system equipped with a conductometric detector.
The study revealed the working parameters for electrophoretic analysis that provided a selective qualitative and quantitative test of five target analytes in 9 min. The optimal composition of the buffer solution and the optimal electrolyte ratios were 30 mmol/dm3 L-Histidine and 30 mmol/dm3 2-(N-Morpholino) ethanesulfonic acid Monohydrate. The correlation between the peak area and the mass concentration was at 0.1–10 mg/dm3 for the target analytes. The approach proved effective in determining chloride, nitrate, sulfate, fluoride, and phosphate ions in whiskey, rum, tequila, moonshine, grain, and rum distillates. The study also included a comparative analysis of the qualitative and quantitative anion profiles in whiskey samples from different countries. All the samples contained 0.22–52.74 mg/dm3 chlorides, 0.60–0.06 mg/dm3 nitrates, 0.25–17.59 mg/dm3 sulfates, and 0.75–12.70 mg/dm3 phosphates.
Research prospects include a metrologically certified method to identify the anion composition of organic and inorganic acids in distilled alcoholic beverages.
The study involved model solutions and 30 samples of distilled alcoholic beverages purchased by random sampling from a retail chain. The chemical analysis relied on a PrinCE 560 capillary electrophoresis system equipped with a conductometric detector.
The study revealed the working parameters for electrophoretic analysis that provided a selective qualitative and quantitative test of five target analytes in 9 min. The optimal composition of the buffer solution and the optimal electrolyte ratios were 30 mmol/dm3 L-Histidine and 30 mmol/dm3 2-(N-Morpholino) ethanesulfonic acid Monohydrate. The correlation between the peak area and the mass concentration was at 0.1–10 mg/dm3 for the target analytes. The approach proved effective in determining chloride, nitrate, sulfate, fluoride, and phosphate ions in whiskey, rum, tequila, moonshine, grain, and rum distillates. The study also included a comparative analysis of the qualitative and quantitative anion profiles in whiskey samples from different countries. All the samples contained 0.22–52.74 mg/dm3 chlorides, 0.60–0.06 mg/dm3 nitrates, 0.25–17.59 mg/dm3 sulfates, and 0.75–12.70 mg/dm3 phosphates.
Research prospects include a metrologically certified method to identify the anion composition of organic and inorganic acids in distilled alcoholic beverages.
12305
Abstract
Many seedlings die early during reforestation. Traditional bareroot technologies often fail in Western Siberia. As a result, containerized technologies have become relevant as they provide higher survival rate in the harsh climatic conditions.
The study traced the development of Scots pine (Pinus sylvestris L.) seedlings grown in a container nursery in the Kemerovo Region. The milled high-moor peat had a degree of decomposition of ≤ 15%. The seeds were treated with fungicides before planting. The seedlings underwent a double treatment against phytophages and phytopathogens during growth.
The article introduces a new agricultural technology for ball-rooted planting stock resistant to phytophages and phytopathogens. The study revealed the developmental stages of pine seedlings and the effect of pesticides on pathogen count. After phytosanitary monitoring and preventive treatments, the seedlings were tested for the effectiveness of pesticides, fungicides, and insecticides as part of pre-planting seed treatment. Such biochemical preparations as Fitoverm (0.4%), Decis Pro, Previkur Energy, and Fitosporin increased the survival rate of the test seedlings. The biological effectiveness of the experimental treatment was 49–53 and 44–50%.
The technology was able to improve the survival rate of pine seedlings in forest container nurseries in the harsh climate of West Siberia.
The study traced the development of Scots pine (Pinus sylvestris L.) seedlings grown in a container nursery in the Kemerovo Region. The milled high-moor peat had a degree of decomposition of ≤ 15%. The seeds were treated with fungicides before planting. The seedlings underwent a double treatment against phytophages and phytopathogens during growth.
The article introduces a new agricultural technology for ball-rooted planting stock resistant to phytophages and phytopathogens. The study revealed the developmental stages of pine seedlings and the effect of pesticides on pathogen count. After phytosanitary monitoring and preventive treatments, the seedlings were tested for the effectiveness of pesticides, fungicides, and insecticides as part of pre-planting seed treatment. Such biochemical preparations as Fitoverm (0.4%), Decis Pro, Previkur Energy, and Fitosporin increased the survival rate of the test seedlings. The biological effectiveness of the experimental treatment was 49–53 and 44–50%.
The technology was able to improve the survival rate of pine seedlings in forest container nurseries in the harsh climate of West Siberia.
1547
Abstract
All agricultural facilities in Russia are currently going through digital transformation. However, the process needs a unified approach for the entire agricultural sector. Neural network methods have already proved extremely effective in various areas of IT. The authors used neural networks to analyze statistic data and assess the performance of agricultural infrastructure.
This study involved technical data from the production cycle of agro-industrial enterprises, namely packaging and greenhouses. The data obtained were analyzed using artificial neural networks.
The procedure included identifying a set of factors that described an agro-industrial complex or some of its properties that corresponded to a specific task. These data were used in planning and making managerial decisions. The program identified five factors that described the state of an agricultural enterprise. These factors were used to build a model while its elements served as output data for the neural network. The model calculated the future state of the object. Trials were run on a limited data set on a multilayer perceptron. The neural network showed reliable results for a small data set. The root mean square error of was 0.1216; the mean modulus deviation was 0.0911.
In this research, modern neural network technologies demonstrated good prospects for the domestic agro-industrial complex as a method of control, management, and dispatching. However, specific operational patterns require further studies.
This study involved technical data from the production cycle of agro-industrial enterprises, namely packaging and greenhouses. The data obtained were analyzed using artificial neural networks.
The procedure included identifying a set of factors that described an agro-industrial complex or some of its properties that corresponded to a specific task. These data were used in planning and making managerial decisions. The program identified five factors that described the state of an agricultural enterprise. These factors were used to build a model while its elements served as output data for the neural network. The model calculated the future state of the object. Trials were run on a limited data set on a multilayer perceptron. The neural network showed reliable results for a small data set. The root mean square error of was 0.1216; the mean modulus deviation was 0.0911.
In this research, modern neural network technologies demonstrated good prospects for the domestic agro-industrial complex as a method of control, management, and dispatching. However, specific operational patterns require further studies.
3313
Abstract
Modern highly sensitive and selective sensors are able to determine biologically active substances, which makes this direction one of the most popular areas of analytical chemistry. The study featured the electrochemical properties of new fiber materials based on single-wall carbon nanotubes with prospects of using them in the voltammetry of ascorbic acid.
The authors developed a new technology to synthesize films from disordered single-wall carbon nanotubes by chemical vapor deposition. Fibers were produced from a solvent by wet-pulling of single-wall carbon nanotubes networks. Thin films of randomly oriented single-wall carbon nanotube bundles were deposited downstream of a floating aerosol CVD reactor, which included a high temperature furnace with a quartz tube. The synthesis of the single-wall carbon nanotube samples was performed at 825°C. Ethanol served as carbon source while ferrocene was used as catalyst precursor. The single-wall carbon nanotubes were collected on a nitrocellulose filter in the form of films with transmittances of 10% in the middle of the visible wavelength (550 nm). The method was optimized to involve air annealing at 300–320°C and a treatment with strong inorganic acids, i.e., HCl, HNO3 + H2SO4. The voltammetric curves recording included background electrolyte, scan rate, and preconditioning. These parameters were selected experimentally to obtain the maximal sensor response to ascorbic acid content. The anodic peak of ascorbic acid in the phosphate buffer electrolyte (pH 6.86) was observed at a potential of +0.2 V. The current and peak area of ascorbic acid oxidation depended neither on the time nor on the conditioning potential of the sensor. The linear dependences of these parameters on the concentration of ascorbic acid stayed within 50–500 μmol/L (8.8–90 mg/L) at a scan rate of 0.1 mV/s. The single-wall carbon nanotube microsensor had a length of 0.5 cm and an average width of 400 μm. Its sensitivity was two times as high as that of a disk glassy carbon electrode with a diameter of 5 mm.
The experimental sensors proved effective in determining ascorbic acid in food products, pharmaceuticals, and biological fluids.
The authors developed a new technology to synthesize films from disordered single-wall carbon nanotubes by chemical vapor deposition. Fibers were produced from a solvent by wet-pulling of single-wall carbon nanotubes networks. Thin films of randomly oriented single-wall carbon nanotube bundles were deposited downstream of a floating aerosol CVD reactor, which included a high temperature furnace with a quartz tube. The synthesis of the single-wall carbon nanotube samples was performed at 825°C. Ethanol served as carbon source while ferrocene was used as catalyst precursor. The single-wall carbon nanotubes were collected on a nitrocellulose filter in the form of films with transmittances of 10% in the middle of the visible wavelength (550 nm). The method was optimized to involve air annealing at 300–320°C and a treatment with strong inorganic acids, i.e., HCl, HNO3 + H2SO4. The voltammetric curves recording included background electrolyte, scan rate, and preconditioning. These parameters were selected experimentally to obtain the maximal sensor response to ascorbic acid content. The anodic peak of ascorbic acid in the phosphate buffer electrolyte (pH 6.86) was observed at a potential of +0.2 V. The current and peak area of ascorbic acid oxidation depended neither on the time nor on the conditioning potential of the sensor. The linear dependences of these parameters on the concentration of ascorbic acid stayed within 50–500 μmol/L (8.8–90 mg/L) at a scan rate of 0.1 mV/s. The single-wall carbon nanotube microsensor had a length of 0.5 cm and an average width of 400 μm. Its sensitivity was two times as high as that of a disk glassy carbon electrode with a diameter of 5 mm.
The experimental sensors proved effective in determining ascorbic acid in food products, pharmaceuticals, and biological fluids.