Nitrogen Mass Fraction Research Articles

Qualitative indicators of milk and fermented milk products when activated zeolite and probiotics are included in the diet of cows

Relevance. The quality of milk depends on the season of the year, the breed of animals, the state of metabolism, and the characteristics of feeding and maintenance technology. The quality of milk determines its technological properties and the quality of its processed products.Methods. The content of somatic cells in milk, the acidity of milk, cottage cheese, yogurt, and syneresis of yogurt were determined. In milk processing products, the content of the mass fraction of nitrogen and crude protein, crude ash, calcium, and phosphorus was determined.Results. When feeding cows with the yeast probiotic activated zeolite and the phytoprobiotic “Provitol”, a significant decrease in the content of somatic cells in freshly milked milk of cows was established by 13.02% (p < 0.05). Significantly lower milk acidity values were established (by 6.00% (p < 0.001) and 12.79% (p < 0.001), respectively), significantly higher yogurt acidity values (by 6.00% (p < 0.001) and 12.79% (p < 0.001), respectively, significantly lower yogurt syneresis (by 4.70% (p < 0.001) and 3.10% (p < 0.01), respectively). The use of activated zeolite and yeast probiotic “Kluver Pro” in the diets leads to a significantly higher content (compared with the control) of the mass fraction of fat in cottage cheese and yogurt — by 10.47 abs. % (p < 0.001) and 4.58 abs. % (p < 0.001).

The use of protein hydrolysate from fish waste as part of microbiological culture media

The need to involve in the processing of significant amount of secondary protein-containing raw materials formed during fish cutting, on the one hand, and on the other hand, the shortage of a source of the protein component of microbiological nutrient media determines the relevance of the work. The goal was to study the possibility of using fish protein hydrolyzate obtained by enzymatic hydrolysis from secondary fish raw materials in microbiological nutrient media. Microbiological and physicochemical methods were used to conduct research. When optimizing the developed algorithm for the fermentation process, a mathematical model of the experiment was used with a minimum number of experiments. An algorithm has been developed for obtaining fish protein hydrolyzate from meat and bone waste from cutting pelagic fish (cod). The hydrolysis parameters were optimized: the concentration of the enzyme preparation is 1.33 % of the total mass of waste, the duration of the fermentation process – 3 hours. The characteristics of the resulting fish hydrolyzate are determined: the mass fraction of total nitrogen – 13 %, amine – 3.6 %, water – 4.6 %, sodium chloride – 2.7 %, fat – 0.3 %. An experimental fish hydrolyzate has been studied as a source of protein nitrogen in accordance with the formulation of a microbiological medium used for counting when growing colonies of microorganisms. The effectiveness of the prepared nutrient media was assessed by comparing the performance coefficients of the experimental and control nutrient media, as well as by identifying test microorganisms grown on the experimental medium. It was established that the growth pattern of test cultures both on the studied nutrient medium and on the control medium was almost the same. Test microorganisms retained their biochemical, morphological and cultural characteristics. The research results showed the possibility of using fish protein hydrolyzate obtained by enzymatic hydrolysis from secondary fish raw materials in microbiological nutrient media.

Elemental composition of <i>Vaccinium vitis-idaea</i> и <i>V. myrtillus</i> (Ercaceae) leaves in green moss pine forests under aerotechnogenic pollution in the Komi Republic

The paper aims at the impact of aerotechnogenic emissions from the largest in the European North pulp and paper production enterprise, namely JSC «Syktyvkar Timber Processing Complex», on the elemental composition (N, S, C, P, K, Ca, Mg, Na, Al, Fe, Mn) of lingonberry and blueberry leaves as the dominant dwarf shrubs in green moss pine forests. The leaves of blueberry and lingonberry growing in pine stands both in the background and contaminated areas were identified to have similar average values of the mass fraction of ash elements in 2009. The content of ash elements in the leaves of dwarf shrubs from the background pine forests was higher than that in leaves collected from the impact zone in 2018. The average values of the mass fraction of ash elements in blueberry leaves were found to access those in lingonberry leaves by 1,5 time both in the background and contaminated areas. There was no regular change in the content of elements in leaves of dwarf shrubs with distance from the source of emission. The differences in the sulfur content in leaves of dwarf shrubs for 2009 and 2018 were within the error limits. No significant differences were found in the values of the mass fraction of nitrogen in blueberry and lingonberry leaves for pine stands located at different distances from the emission source. The nitrogen content in lingonberry leaves was significantly lower than that in blueberry leaves for both observation periods. There was no significant difference in the total nitrogen content in blueberry and lingonberry leaves between 2009 and 2018.

Some results of the introduction study of <i>Leonurus cardiaca</i> plants in the middle taiga subzone of the Komi Republic

The article summarizes the results of many years of studying Leonurus cardiaca L. under cultural conditions in the North. It was revealed that in the first year of life, with the seedling method of cultivation, motherwort plants are in the pregenerative period. The transition of individuals into the generative period is noted in the second year of life. The winter hardiness and stability of plants in agrocoenosis is quite high. Under cultural conditions, specimens of L. cardiaca plants of different geographical origins retained the rhythms of seasonal development characteristic of this species. It was revealed that plants of L. cardiaca are characterized by extended periods of flowering (38–44 days) and fruiting (35–40 days). The growing season from the beginning of regrowth to seed collection was 127–132 days. In the years studied, different samples of L. cardiaca formed mature seeds weighing 1000 pcs. seeds 0,86–1,03 g and laboratory germination of 55–91%, which meets the requirements for the quality of seed material of this type. L. cardiaca plants reached their maximum development in the third to fifth years of life, being in a middle-aged generative ontogenetic state: plant height 98–166 cm, shoot-forming capacity – 18–22 pcs. per individual, inflorescence length 26–36 cm, raw material of the main shoot 7,2–8,6 g of wet and 2,1–2,9 g of air-dried phytomass. For the first time the mass fraction of nitrogen (2,4–2,9%) and the amino acid composition of proteins were determined in the above-ground raw phytomass of L. cardiaca. 17 amino acids were quantified, including seven essential ones (39,4% of the total). The highest content in plants was observed for amino acids: glutamic (12,5%), aspartic (11,6%), leucine (9,9%), lysine (8,3%), alanine (6,6%), valine (6,6%) and arginine (5,8%).

ОТЗЫВЧИВОСТЬ ГИБРИДА КУКУРУЗЫ НУР НА ЛИСТОВЫЕ ПОДКОРМКИ КАРБАМИДОМ И СТИМУЛЯТОРОМ РОСТА ИЗАГРИ ВИТА В ПОЧВЕННО-КЛИМАТИЧЕСКИХ УСЛОВИЯХ РЕСПУБЛИКИ ТАТАРСТАН

The feed potential of the universal early-maturing hybrid corn Nur was studied in the conditions of the Ancestral region of the Republic of Tatarstan on gray forest heavy loamy soils. The content of humus in the arable layer was characterized as increased by 4.4 %, mobile phosphorus as very high - more than 377 mg/kg, exchangeable potassium increased – 124 mg/kg. The soil had a medium reaction close to neutral (pH 6.3). Meteorological conditions in 2023 were characterized as arid with a lack of precipitation during the growing season of corn. To obtain high-quality feed from corn, different corn nutrition systems were studied: without fertilizers, background N16P16K16, background N16P16K16 + urea leaf dressing in the 5-7 leaf phase, background N16P16K16 + Izagri Vita leaf dressing in the 5-7 leaf phase, background N16P16K16 + Izagri Vita leaf dressing in the 5-7 leaf phase and cob formation. Izagri Vita is a growth stimulant with trace elements. Improving the nutritional conditions of corn extends the growing season by 2-3 days. Corn responds positively to the application of mineral fertilizers and carrying out leaf fertilization with carbamide. This technique ensures the formation of the highest plant height (159.7 cm) and leaf area (42.19 thousand m2/ha). The largest aboveground mass was formed on the von NPK+ variant Izagri Vita 44.50 t/ha. Biometric indicators of corn also improved on fertilized food backgrounds. The highest yield of green mass was obtained on the variants background NPK and background NPK + Izagri Vita (2 phases) (45.81 and 41.88 t/ha). The increase in yield from the applied mineral fertilizers amounted to 16.25 and 12.31 t/ha. Better nutrition of corn provides a more nutritious feed from corn. The NPK background variant had the highest mass fraction of dry matter (86.3 %), crude fiber (35.0 %), and NPK background + From graphite, where the mass fraction of nitrogen was 20.5 g/kg, crude protein 128.2 g/kg, phosphorus 1.0%.

Effects of nitride precipitation on delta phase formation in additively manufactured nickel superalloys

Additively manufactured Inconel 625 is particularly susceptible to the formation of niobium-rich δ-phase precipitates in the interdendritic regions during high temperature exposure. With specific minor alloying element combinations and nitrogen mass fractions on the order of 0.1 %, the formation of δ-phase can be suppressed through the precipitation of nitrides. For example, mass fractions of 0.39 % silicon and 0.03 % titanium led to the precipitation of Z-phase and η-nitrides, which consumed the excess niobium in the interdendritic regions and limited δ-phase formation. Even when holding the material at a temperature of 870 °C for 1000 h, the δ-phase volume fraction was approximately 2 %, which is far below the 6 % level observed in the wrought condition. When the titanium mass fraction was increased to 0.21 % and the silicon mass fraction decreased to 0.05 %, titanium-rich MN nitrides formed within the interdendritic regions instead. Since much of the Nb in these regions was not consumed by the nitrides, δ-phase formation was promoted and reached volume fractions above 10 %. The addition of a hot isostatic pressing step prior to high temperature exposure in both alloys produced a more uniform niobium distribution and minimized δ-phase formation at shorter times. At extended times, trends in the δ-phase volume fractions were similar to those observed in the as-deposited condition, with the initial alloy compositions driving differences in the distribution of excess niobium available for δ-phase formation.

Synthesis of cellulose nitrates from Miscanthus × giganteus var. KAMIS cellulose obtained under pilot production conditions

The work is devoted to the study of a novel national raw material resource Miscanthus × Giganteus var. KAMIS, which is positioned as one of the most promising natural sources for obtaining high-quality cellulose for the purpose of its further chemical functionalisation. A batch of technical cellulose isolated from raw materials under pilot production conditions using the nitric acid method having a cellulose content of 50.2% was characterized by high α-cellulose mass fraction (92.8%) and degree of polymerisation (1200) values. On the basis of the pilot batch of technical cellulose, a sample of cellulose nitrates offering basic functional properties was obtained: mass fraction of nitrogen – 11.18%; viscosity – 48 MPa·s; solubility – 94%. The synthesised sample is characterized by extremely high solubility in acetone, confirming the production of cellulose nitric acid esters, and a high yield of 150%. IR-Fourier spectroscopy was used to identify the main functional groups in the experimental batch of technical cellulose (3384, 2902, 1639, 1428, 1370, 1319, 1161, 700–500 cm-1) and in a sample of cellulose nitrates (1659, 1278, 834, 746, 683 cm-1). Acorresponding affiliation to cellulose and cellulose nitric acid esters was established. The structural and morphological features of the fibres of the experimental batch of technical cellulose and a sample of cellulose nitrates were characterised using scanning electron microscopy. Combined methods of thermogravimetric and differential thermal analyses were used to establish high initial temperature (197 °C) and specific heat of decomposition (6.92 kJ/g) values at the beginning of intensive decomposition. The obtained results substantiate the possibility to chemically functionalise cellulose isolated from a new alternative source into cellulose nitric acid esters with satisfactory functional properties.

Temperature, microbiological and chemical composition of broiler chickens’ excrement with litter after its composting with different doses of biodestructor

The rapid growth of production volumes of broiler chicken products both in our country and in most countries of the world is combined with an increase in industry waste. A significant percentage of this waste is poultry droppings with litter. In the absence of implemented technologies for rational disposal of broiler chicken droppings, economic and ecological problems arise locally. Considering the above, the search for effective methods of disposal of broiler chicken droppings is of scientific and practical importance. Composting poultry droppings with litter (sawdust of non-coniferous trees) can be an alternative method of rational disposal of this waste. To accelerate the fermentation of broiler litter, there is a practice of using various microbiological preparations. The effectiveness of using a biodestructor containing bacteria: Bacillus spp., Bacillus subtilis, Bacillus megatherium, Bacillus mesentericus, Bacillus mycoides during composting of broiler chicken excrement and its effect on the microbiological, chemical and physical parameters of fermented biomass remains unexplored. To conduct an experiment, 30 kg samples were formed from the excrement with the litter taken from the poultry house after broiler chickens had been reared for 42 days. In the control group, excrement samples were treated with water without a biodestructor. In the 1st, 2nd, and 3rd research groups, broiler chicken droppings were moistened with biodestructor solutions providing its doses of 143, 1430, and 2860 mg/t, respectively. Temperature and microbiological indicators were determined in the litter of broiler chickens during composting. In non-fermented litter of broiler chickens and litter composted for 150 days using a biodestructor, the crude protein content, mass fraction of Calcium, total Nitrogen and Phosphorus were determined. It has been established that the introduction of a biodestructor at a dose of 2860 mg/t of manure with a moisture content of 60.0 % leads to an increase in the activity of biochemical processes, which is confirmed by an increase in the temperature of the compost during the first hundred days of fermentation. The higher the dose of biodestructor was added to the litter of broiler chickens, the higher the KMAFAnM indicator and the numbers of Bacillus spp. bacteria in compost were higher. A regularity has been established that with the increase in the amount of biodestructor in the litter of broiler chickens, the number of Staphylococcus and Clostridium bacteria in the latter decreases. The use of a biodestructor at a dose of 2860 mg/t of broiler chicken droppings contributes to the increase of Nitrogen, crude protein, and Phosphorus in the compost and accelerates its mineralization compared to the control.

Effects of Oxygenated Brackish Water on Pakchoi (Brassica chinensis L.) Growth Characteristics Based on a Logistic Crop Growth Model

Oxygenated irrigation can improve soil physical and chemical properties and increase vegetable yields. It provides an effective method for safe and efficient utilization of brackish water, but its growth-promoting pathway is unclear. We investigated the effects of brackish water culture at five dissolved oxygen concentrations (9.5 (CK), 12.5, 15.5, 18.5, and 22.5 mg/L) on pakchoi (Brassica chinensis L.) growth characteristics by hydroponics experiment, and the logistic model to fit and analyze pakchoi growth characteristics. At a brackish water dissolved oxygen concentration of 18.5 mg/L, nitrogen mass fraction was significantly higher than in a control treatment by 43.4%, and pakchoi effective accumulated temperature increment during vigorous plant height and root length growth was significantly lower than other treatments. The logistic model effectively simulated pakchoi plant height and root length growth, and both theoretical maximum plant height and root length reached their maximum values at 18.5 mg/L dissolved oxygen concentration. Path analysis showed that the maximum net photosynthetic rate and nitrogen mass fraction were the main factors affecting aboveground pakchoi fresh weight. In conclusion, a dissolved oxygen concentration of 18.5 mg/L in brackish water is more appropriate for pakchoi to achieve high yield under brackish water hydroponics conditions. Our results provide guidance for the safe and efficient utilization of brackish water in green and efficient vegetable production.

The results of the initial introduction of <i>Bupleurum aureum</i> Fisch. ex Hoffm. in the middle taiga subzone of the Komi Republic

The paper summarizes the results of a long-term introduction study of plants of golden boletus in the collection of medicinal plants of the Botanical Garden of the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences. The primary introduction of the species into new growing conditions became possible only by transferring living plants to cultivation from the places of natural growth of the Tomsk Region, followed by propagation of plants from seeds of their own reproductions. The optimal methods of seed propagation of this species in the conditions of the North were revealed: winter sowing with freshly harvested seeds and self-sowing of seeds with further transplantation of emerging seedlings to a new plot with a feeding area of 30 30 cm golden is distinguished by high survival rate, winter hardiness and stability in the coenosis. The mass transition of plants into the generative period occurred in the second third year of life. The phenology and dynamics of plant growth have been studied. The rhythm of the seasonal development of plants in. golden in culture in the North corresponds to the new soil and climatic conditions of cultivation. The growing season is 96100 days. Golden boletus regularly forms full-fledged seeds, which, after undergoing natural stratification under snow cover, germinate in the spring and give a large self-sowing. Real seed productivity (the number of mature full-fledged seeds) in plants c. golden of different ages varies over the years from 420 to 570 seeds per shoot. The morphobiological signs of the generative shoot were studied in culture and the amplitude of their variability was determined. High and very high levels of individual variability of signs of the floral zone of the shoot indicate the possibility of targeted selection of more productive individuals within the population. For the first time, data on the content of proteins and its amino acid composition in plants are presented. The mass fraction of nitrogen (in terms of crude protein) in the aboveground phytomass was 1,51,8%. In proteins from aboveground phytomass, 17 amino acids were identified, including 7 essential ones (threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine). The proportion of essential amino acids averaged 39% of the total. The highest rates were noted for amino acids: glutamic, aspartic, leucine, lysine, alanine and valine 13,1, 10,7, 9,2, 8,1, 6,7 and 6,2% respectively.

Microscale Simultaneous Measurement of Carbon and Nitrogen Isotopes on Natural Diamond

Simultaneous analysis of carbon and nitrogen isotope ratios by SIMS was applied for the first‐time to a natural diamond from the Kelsey Lake kimberlite, State Line Distinct, Colorado (UWD‐1). This in situ procedure is faster, reduces sample size for analysis, and measures both isotope ratios from a single ~ 10 μm diameter pit, a critical advantage for zoned diamonds. The carbon isotope ratio (expressed as δ13CVPDB) of the bulk UWD‐1 crystal, determined by the conventional combustion method in the present study, is ‐5.9‰ ± 0.2‰ (VPDB, 2s). Nitrogen mass fraction ([N]) and isotope ratio (expressed as δ15NAir) were determined by stepwise combustion and gas‐source mass‐spectrometry, resulting in 553 ± 64 μg g‐1 and ‐6.7‰ ± 1.1‰ (Air, 2s), respectively. Secondary ions of 12C2‐, 12C13C‐, 12C14N‐, and 12C15N‐ were simultaneously measured by SIMS using three Faraday cups and one electron multiplier. The spot‐to‐spot reproducibility of δ13C and δ15N values for the UWD‐1 (178 spots on sixteen chips, 10 μm spots), were 0.3‰ and 1.6‰, respectively (2s). While 12C14N‐/12C2‐ ratios, which are an indicator for [N], varied up to 12% among these sixteen chips, such variation did not correlate with either δ13C or δ15N values. We propose that UWD‐1 is a suitable reference sample for microscale in situ analysis of δ13C and δ15N values in diamond samples.

Development of titanium-based certified reference materials

The Institute for Certified Reference Materials (ICRM) issued for the first time certified reference materials (CRM 11777-2021) of the mass fraction of hydrogen, oxygen and nitrogen in titanium-based materials, i.e., titanium alloy 2V (ISO 1-1) and titanium VT 1-00 (ISO 1-2). The finished material is presented in the form of cylinders 2.5 mm in diameter and 5-6 mm height. The mass of a cylinder is about 0.1 g. To certify gas-forming elements, we used the methods of fusion under inert gas flow (hydrogen, oxygen, nitrogen) and high-temperature vacuum extraction with mass spectroscopy (hydrogen). The analyzers were calibrated using CRM, a gas dose (for hydrogen), and a substance of constant stoichiometric composition (potassium nitrate). Conditions for the determination of the mass fraction of hydrogen, oxygen, and nitrogen in titanium and titanium alloys using an ELTRA ONH-2000 gas analyzer in solid materials have been refined in the analytical laboratory ICRM. The accuracy indicators (assigned characteristics) of the measurement procedure were determined using a great bulk of experimental data.

Estimating nutrient transport associated with water and wind erosion across New South Wales, Australia

Nutrient transported from soils to water bodies not only threatens agricultural productivity and food security but also causes the degradation of water quality and the environment in many parts of the world. However, nutrient transport through soil erosion is often ignored in nutrient cycle studies; there is little understanding of how much nutrient is lost through water and wind erosion. In this study, we attempted to assess soil nutrient transport due to both water and wind erosion and its spatial and temporal variability across New South Wales (NSW), Australia. We estimated the mass fraction (%) of total nitrogen (N), total phosphorus (P) and soil organic carbon (SOC) in the eroded soil, and the total nutrient stock of the soil layer down to 200 cm using water and wind erosion models and digital soil mapping. The estimated average N, P and SOC stocks in NSW topsoils (0–5 cm) are 160, 43, and 2970 kg ha−1 respectively. There are great variations in the transport of nutrients by erosion in space and time, ranging from near zero in the Western region to 395 kg ha−1 yr−1 in the North Coast region. The average total nutrient transport rate is about 2.4 % of the surface soil (0–5 cm) total stock in NSW due to both water and wind erosion. The total cost of nutrient transport is estimated at 4.2 billion Australian dollars for the entire state of NSW and 0.2 billion dollars from the cropping lands per year. The areas with the highest nutrient transport rates are the North Coast and Hunter regions due to the relatively high water erosion and nutrient content of the soils. On average, water erosion contributes up to 98 % of the total nutrient transport across the state as a whole, but wind erosion can contribute up to 12 % of the total transport in Spring (i.e., September). This study is the first attempt to investigate nutrient transport from both water and wind erosion in Australia. The methodology and findings contribute to the knowledge of nutrient transport due to erosion in broad nutrient cycle studies.

Evaporation of single moving liquid nitrogen droplet: Experimental study and numerical simulation

Liquid nitrogen (LN2) spray is composed of numerous LN2 droplets. Understanding the spray evaporation process requires firstly studying the evaporation mechanism of single moving LN2 droplet. This study focuses on experimental study and numerical simulation for evaporation characteristics of single moving LN2 droplet. A visualized experimental setup was established to investigate the dynamic evaporation characteristics of single moving LN2 droplet. The temporal evolution of LN2 droplet diameter and traveling distance was measured. The mass, energy and momentum equations between the droplet and the surrounding gases, as well as their coupled solving algorithm, are also developed to predict the temporal diameter, temperature and velocity of single moving droplet. Six typical gas-phase evaporation models are integrated into an in-house program so as to evaluate their accuracy and applicability for the droplet with a high evaporation rate. The results show that all of the six models underestimate the evaporation rate of single moving LN2 droplet. It is suggested that the Stefan blowing effect should not be taken into consideration for single moving LN2 droplet. A novel gas-phase model is then proposed for the evaporation of single moving LN2 droplet. The model can accurately predict the evaporation rate of single moving LN2 droplet when the relative velocity of LN2 is greater than 0.5 m/s, and the prediction error is within 1.1%. Furthermore, the model is also used to investigate the effects of key droplet parameters in real LN2 spray, including the initial diameter, the initial velocity, the ambient temperature and the mass fraction of nitrogen in the ambient gases, on the evaporation of single moving droplet.

Analysis of complex changes in salmon salting by injection using the food additive PRE-LACKS

The paper presents the results of a comprehensive assessment of the quality of delicacy fish products - salmon fillets of weak salt made using the food additive PRE-LACKS (LLC "Vash technologist", St. Petersburg, Russia) and curing by injection. For the first time, the influence of technological factors has been studied (the concentration of a food additive (in the range recommended by the manufacturer from 3 to 5 % with a step of 1 %), as well as the value of the hydromodulus (in the range from 5 to 20 % with a step of 5 %) characterizing the ratio of masses of the fillet introduced into the thickness when injecting brine and a salted fillet piece) on the formation of a complex indicator of the finished product quality. The developed scale for a comprehensive assessment of the quality (K) of lightly salted salmon fillet of injection salting is presented, including the main groups of indicators - organoleptic and rheological, nutritional value and physico-chemical. The scale includes weighting coefficients based on the results of experimental and sensory studies - both group and for each quality indicator taken into account. It has been shown that using the fuzzy logic method made it possible to obtain the values of the selected influencing factors optimized according to the criterion of achieving the maximum value of K (in the range from 0.9 to 1.0 conventional units, corresponding to the category "delicacy product") - the concentration of the food additive and the value of the hydromodulus - 4 and 15 %, respectively. The results of assessing the influence of selected technological factors on the yield of a semi-finished product immediately after salting by injection, on the yield of finished low-salted products (after ripening), on indicators characterizing the completeness of its maturation (buffering, the ratio of the mass fraction of non-protein nitrogen to the mass fraction of total nitrogen, total acidity, mass fraction of amine nitrogen) have been presented. Based on the results of the research, technological recommendations are formulated for salting salmon by injection using the PRE-LACKS food additive to increase the yield of finished products and improve its consumer properties.

Eco-Stoichiometric Characteristics of Rhizosphere and Bulk Soils of Smilax china L. along Vertical Zone Spectrum of Fanjing Mountain.

To explore the correlations between nutrients and stoichiometric characteristics in the rhizosphere and bulk soils of understory Smilax china L. in forest ecosystems at different altitudes and to clarify the rhizosphere effect of understory vegetation in forest ecosystems and its response strategy to altitude, providing a theoretical basis for better forest ecological environment protection and high-quality development in Fanjing Mountain. Understory Smilax china L. at four different altitudes were selected, with the differences and influencing factors of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) mass fractions and stoichiometric ratios in their rhizosphere and bulk soils analyzed. The average mass fractions of total C, total N and alkali-hydrolyzed N in the rhizosphere and bulk soils of Smilax china L. at different altitudes were 224.43 and 181.55 g·kg−1; 9.56 and 6.81 g·kg−1; and 648.19 and 600.70 g·kg−1, respectively. The rhizosphere effect of Smilax china L. was significant at altitudes of 500 m and 1000 m but became not so prominent with the rise of altitude. The C:N ratio in the rhizosphere and bulk soils ranged from 19.51 to 39.75 and the C:P ratio ranged from 225.29 to 543.05. C accumulation is greater than N accumulation in the rhizosphere and bulk soils of Smilax china L., and both present P limitation. Based on the comprehensive analysis of the mass fractions and eco-stoichiometric ratios of soil nutrients, the P limitation in Fanjing Mountain forest ecosystem is commonly seen and should be addressed.

Response of sedimentation rate to environmental evolution in Da River Reservoir in Southwest China.

Lake sediment records the evolution process of the interaction between human and nature. It is important to master the lacustrine sedimentation rate for the ecological environment assessment of catchment. A 60-cm sediment core was collected in the Da River Reservoir during 2019 to analyze radionuclides (210Pb and 137Cs) massic activities, grain size, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and metals (Mn, Cu, Al, and Pb) mass fractions to reconstruct the response of sedimentation rate to environmental evolution. The environmental changes in the small catchment were classified into the following three stages through cluster analysis (CA) for geochemical parameters in the sediment core: phase I (1881-1985), phase II (1987-1999), and phase III (2000-2018). The average depth sedimentation rates (ADSRs) of the three stages were 0.33, 0.90, and 1.50cm/year, respectively. The sedimentation rates increased from the bottom to the surface layer, indicating that the exogenous inputs into the reservoir have been occurring. The sediment deposition in phase III was strongly disturbed by the environmental changes (such as warmer climate and intensified land use). Therefore, sedimentation rates showed a rapid increase. Both Pearson correlation analysis and redundancy analysis (RDA) showed that sedimentation rates were positively correlated with climatic factors, particle size, nutrients and metals mass fractions, elemental ratios, and socioeconomic parameters. Sedimentation rates show high sensitivity to anthropogenic activities and climatic change, which can be used to reconstruct the environmental evolution process at a small catchment scale.

OBTAINING AND CHARACTERISTICS OF MANNAN-PEPTIDE NANOHYBRID

Bioactive peptides belong to a new generation of biologically active regulators with a wide range of important physiological effects. This determines the prospects for their use in functional foods as dietary supplements and medicine. The main source of such bioactive peptides is cow's milk. It contains proteins, which include 80% caseins. Like other bioactive compounds, they are exposed to unwanted changes in technological processes and during transit along the gastrointestinal tract. In order to improve their stability and increase bioavailability, conjugates obtained by the Maillard reaction have recently been used. Currently, it is positioned as a promising way to prevent the destructive impact of external factors. This article highlights the results of studies designed to determine the feasibility of casein fragmentation with papain to obtain bioactive peptides and the subsequent creation on their basis of a nanohybrid with a mannan component by the Maillard reaction. Enzymatic hydrolysis of sodium caseinate with papain was carried out with varying the duration of the hydrolysis process (30, 60, 120, 180, 240 min). The yield of protein proteolysis products depending on the duration of the process ranged from 77.8% to 83.9%.Enzymatic hydrolysis of sodium caseinate contributed to a significant increase in the products of its fragmentation mass fraction of amine Nitrogen – from 4561.4 to 5687.5 mg/100 g (4.6–5.7%), which is 3.5–4.4 times more than the content of free amino groups in the original sodium caseinate. Among them, almost 1/2 arebioactive peptidescontaining up to 20 amino acid residues.The mannan-peptide nanohybrid was incubated with biopeptides with modified coffee mannan, which had the ability to dissolve in water.The reaction mixture was exposed to 60 oC for 6 h. The yield of lyophilized product was 38.1%, the mass fraction of mannan reached 10.6-10.9%, and peptides, respectively, – 89.1–89.4%. The protective effect of the polysaccharide component against the peptide component was evaluated in vitro in a pepsin-trypsin system. It was found that the stability of peptides in the nanohybrid is much higher than in the original hydrolyzate. The use of the created nanohybrid is possible both to obtain protective shells of labile biologically active substances and to increase the bioavailability of peptides when they are included in dietary supplements and functional foods.

Technology of Quick-Frozen Flour Fish Culinary Products

In this article, the results of the development of the functional fish culinary product “Thorny Skate and Cod Pie” are presented. A traditional recipe was used for making the yeast dough for the pie. The pie filling recipe was designed using Fuzzy Logic in the Matlab software package.Optimized parametersfor the selected sensory evaluation of the pie were calculated. On the basis of a priori information, key components of the filling (including the fraction of the fish components and skate meat) were chosen as the factors of interest. According to the simulation results, the optimal values werea 50/50 percentage for the first and the second factor respectively, and this providedthe maximum organoleptic assessment (five points on a five-point scale). The simulation results were compared with the results of the organoleptic evaluation of the pie made according to the optimized recipe, and their sufficient convergence was shown. The indicators of mass fraction of amine nitrogen and nitrogen of volatile bases was studied, as well as the microbiological safety indicators of flour fish culinary products, in accordance with the requirements of the Technical Regulations of the Eurasian Economic Union 040/2016 ”On the safety of fish products”. The results showed a high efficiency of the shock freezing of the semi-finished product, brought to semi-readiness, for long-term storage (120 days at a temperature no higher than minus 18 ∘C), without reducing the quality or safety of the pie. The product had a cholesterol content from 220 to 260 mg%, which allowed it to be classified as functional. The nutritional values of the product (mass fraction of protein, fat, carbohydrates, and amino acid composition) are presented.
 Keywords: thornyskate, functional product, pie with thornyskate and cod, shock freezing

Performance improvement of a PEMFC with dead-end anode by using CFD-Taguchi approach

In this paper, the design of experiments by the Taguchi method integrated with computational fluid dynamics simulation has been implemented for determining optimum operating conditions. A numerical model has been made with ANSYS code for proton exchange membrane fuel cell with the dead-end anode mode. This study assesses the impact of four factors, namely gas diffusion layer porosity, hydrogen mass fraction, nitrogen mass fraction, and water saturation. The influence of inlet pressure (Pin,1 = 104Pa, Pin,2 = 3.104Pa, and Pin,3 = 6.104Pa) and relative humidity (RH1 = 0%, RH2 = 50%, and RH3 = 100%) have been studied using the integrative approach. For Pin,1, Pin,2, and Pin,3, the optimum levels yielding a superior performance were (L5, L3, L2, and L1), (L5, L3, L2, and L2), and (L5, L3, L3, and L1), respectively. For RH1, RH2, and RH3, the optimum levels yielding a better performance were (L5, L1, L3, and L1), (L5, L3, L1, and L1), and (L5, L3, L2, and L1), respectively. Our findings revealed that the electrical current density reflecting the cell performance decreased with increasing the water accumulation, the nitrogen mass fraction, and decreasing the hydrogen mass fraction. The percentage error between Taguchi calculations and computational outputs of power densities was 0.23%, 0.19%, 0.45%, 0.28%, 0.2%, and 0.16%.