Refractometric Method Research Articles

Technology of preparation and determination of the properties of kvas from table beet for use in bakery

In connection with the deterioration of the health of the population of Ukraine, the primary task should be to enrich the usual diet with products of functional purpose and to add natural biologically active additives that contribute to the removal of radionuclides, toxins, normalization of the body's systems and increased immunity. This work is devoted to the study of the process of beet processing and its further use in the bakery and confectionery industries. The refractometric method was used to determine the content of soluble solids. The content of trace elements was determined using the atomic adsorption method. When preparing kvass from table beets, additional raw materials were added: sprouted flax seeds, whey, yeast, viburnum powder, rye bread crackers. It was established that the variety of the Dutch selection Roket differs from the varieties Bordeaux 237 and Cylindra in terms of dry matter, organic acids, dyes and sugars. It is important to note that when improving kvass preparation technology, optimal fermentation conditions and dosing of additives are taken into account in order to maximize the shelf life of the product without losing its quality. In view of the increase in the number of genetic and complicated diseases, it is worth noting the introduction of specialized dietary programs, which are gaining more and more relevance. Such programs have been found to ensure food security and meet all essential nutrient needs. Considered the problem of the need for constant improvement of recipes of food products, study of new gluten-free alternatives and provision of access to high-quality gluten-free products. Studies have proven that the use of natural raw materials in the production of beet kvass is an effective means of improving its quality characteristics. Therefore, a promising direction in the production of flour products is the improvement of the recipe of the existing assortment due to the use of natural plant components of increased biological value. Kvass from table beet can be a source of natural biologically active substances (BAR). Table beets have a rich chemical composition. The nutritional value of beets is additionally balanced by the content of sugars and acids (citric and oxalic), the content of organic substances, minerals and vitamins. The production of bakery products using kvass from table beet as a natural food additive is relevant today.

Study of modern aviation hydraulic fluids based on phosphate ester by refractometric method

Study of modern aviation hydraulic fluids based on phosphate ester by refractometric method

Evaluation of portable refractometr as an alternative method to biuret assay for measurement of serum total protein in horse

The measurement of serum total protein (TP) is commonly performed by the biuret method. Refractometery which is less expensive and faster method also determines serum protein; however its accuracy is controversial. Therefore the primary objective of this study was to investigate portable refractometer as an alternative method to the biuret assay for measuring total serum proteins in horse serum. Serum from 50 male horses admitted to the society of the protection of animals’ abroad (SPANA) clinic was collected and measurement of serum total protein determined using portable refractometer and biuret method. The statistical differences between both methods were analyzed using a paired t-test and the correlation was determined by spearman correlation test. The results of this study demonstrate that there were no statistically significant variations in the mean total protein measured with the refractometer and biuret method (P > 0.05). The correlation between two methods using spearman correlations revealed high correlation between refractometry and biuret assay measurements of TP concentration r = 0.855. Bland–Altman plots indicated that biases indicating the analytic error was (4/50) 8% which is less than allowable total error for total protein determination (< 10%). Therefore portable refractometery can be used as an alternative to biuret method for serum total protein in horse as it is easy to use, quick turnaround time, and is inexpensive.

Refractometric method to study the coating thickness of diamond nanoparticles

A method based on refractometric measurements of liquid nanodisperse systems has been developed to determine the quantitative composition of diamond-amorphous carbon colloidal particles. It was demonstrated that by measuring the changes in the refractive index and density of sols caused by changes in particle concentration it is possible to determine the thickness of the particle surface layer, assuming its composition is known. Within the framework of the Mie theory, the influence of the size of diamond particles with carbon coating on the refractive index of hydrosols was quantified. The limits of applicability of the developed method have been determined. For several polydisperse sols with coated diamond particles the thickness of carbon coating was determined.

INVESTIGATION OF THE INFLUENCE OF POLYVINYL PYRROLIDONE (PVP) ON HYDRATION PROCESSES IN ELECTROLYTES

The paper investigates the effect of polyvinylpyrrolidone (PVP) on the sum of the hydration numbers of anions and cations of salts KJ and К2SO4. The sum of hydration numbers was determined by the refractometric method. The data obtained show that the presence of the polymer in the electrolyte solution reduces the value of h,+ h2 which is associated with competition between polymer molecules and ions during the hydration process.

Current Issues in Determining Fat Content in Food Products and Food Raw Materials (Review)

The article raises the problem of incomparability of measurement results obtained by different methods of measuring fat content in food products and food raw materials. The problem identified by the author can be solved by developing metrological support for measurements in the food industry. The purpose of the study is to analyze methods for measuring fat content in food products and food raw materials, as well as to revise the state of their metrological support. A brief description, applications, advantages and limitations of extraction-gravimetric, butyrometric, refractometric, chromatographic, ultrasonic, turbidimetric, NMR, and IR spectroscopic methods for measuring fat content are presented. Standardized measurement techniques regulated in national (GOST R), interstate (GOST), and international (ISO, AOAC) standards are analyzed, taking into account the method used, areas of application, and metrological characteristics. An overview of testing equipment and measuring instruments for implementing various methods for determining fat content is given. Particular attention is paid to the consideration of certified express analyzers of food products and food raw materials. A list of certified reference materials for the composition of dairy and grain-milk products, fish and meat products, oilseeds and their processed products, compound feed, egg powder and wheat crackers with a certified value of the mass fraction of fat is provided, their metrological characteristics and certification methods are listed. Based on the results of the study, the main features and problems of ensuring the uniformity of measurements of fat content in food products and food raw materials were formulated, and perspective directions for the development of metrological support were identified.

Profile of Phenolic Compounds and Antioxidant Activity of Celery (Apium graveolens) Juices Obtained from Pulp after α-Amylase Treatment from Aspergillus oryzae.

The purpose of this study was to determine the content of certain phenolic compounds, antioxidant activity, pressing efficiency, extract content, and sugars in celeriac juices obtained from the pulp after α-amylase treatment from Aspergillus oryzae. The test material consisted of peeled and unpeeled celery pulp kept at a temperature of 25 °C with and without the enzyme for a period of 30 and 60 min. The juices obtained from them were analyzed for the content of selected phenolic acids and flavonoids using the UPLC-PDA-ESI-MS/MS method, for antioxidant activity measured using the ABTS˙+ and DPPH˙ method, and for the total polyphenol content using the F-C method. Additionally, the juice pressing efficiency, the extract content using the refractometer method, and the sugar content using the HPLC method were checked. Significantly higher antioxidant activity, pressing yield, and average content of caffeic acid glucoside, quinic acid, kaempferol-3,7-di-O-glucoside, and chrysoeriol-7-O-apiosylglucoside were obtained in juices from peeled celery. Maceration of the pulp with amylase resulted in a significant reduction in antioxidant activity compared to control samples. An is-total increase of 17-41% in total flavonoid content was observed in all juices tested after treatment with the enzyme for 30 and 60 min, and the phenolic acid content increased by 4-41% after treatment of the pulp with amylase for 60 min. The 60 min holding of the pulp at 25 °C, including with the enzyme, was shown to decrease the antioxidant activity and the content of quinic acid, ferulic acid, and chrysoriol-7-O-apiose-glucoside in the juices tested compared to the samples held for 30 min, while the content of other phenolic acids and flavonoids increased. In addition, after 60 min of enzymatic maceration, the pressing yield of the juices increased.

Evaluation of Sheep Colostrums According to Time after Lambing by Brix Refractometer Method and Color Scoring

The aim of the study was to determine the effects of breed and post-lambing time on sheep colostrum quality. In this study, colostrum samples taken at different times after lambing from 4 different sheep breeds (Tuj, Awassi, Morkaraman, Akkaraman) raised in Turkey were compared using Brix refractometer and color scoring. The sheep included in the study were placed in different paddocks according to their breeds. In the first week after lambing, a total of 7 colostrum samples were collected from each ewe, every 12 hours for the first 3 days and on the 7th day (mature milk sample). According to the data obtained from the study, it was determined that colostrum quality was affected by breed and milking duration (p&lt;0.05). Brix values of colostrum in the first and second milking were found to be higher in the Akkaraman breed than in the Morkaraman breed (p&lt;0.05). Additionally, it was determined that the color score decreased over time after lambing and this decrease was statistically significant (p&lt;0.05). In conclusion, since the quality of sheep colostrum varies depending on breed and time, the quality of the colostrum to be fed for lamb health and performance must be determined in advance

Drinks using extracts of medicinal plant raw materials

In connection with the deterioration of the health of the population of Ukraine, the primary task should be to enrich the usual diet with products of functional purpose and to add natural biologically active additives that contribute to the removal of radionuclides, toxins, normalization of the body's systems and increased immunity. Therefore, this work is devoted to the study of the process of extracting biologically active substances from medicinal plant raw materials (plantain and hypericum) with the aim of obtaining extracts, based on which new functional drinks have been developed. The refractometric method was used to determine the content of soluble solids. The content of trace elements was determined using the atomic adsorption method. It was established that for a significant increase in the transition of biologically active substances to the extract, a rather long time is necessary, and the duration of the infusion that we took is insufficient to extract a large number of valuable components from medicinal plant raw materials. Therefore, the best parameters of the process of extracting valuable components from plantain and and hypericum were studied. For plantain, the obtained parameters should correspond to hydromodule 3, temperature 60º C and extraction duration 35 min., for hypericum - hydromodule 3, process temperature 70º C, extraction duration 35 min. The content of soluble solids and the quantitative composition of such trace elements as copper, iron, manganese and zinc were determined in the obtained extracts at different extraction temperatures. Based on the obtained results, new drinks were developed using the traditional Ukrainian raw materials of apples, carrots and table beets and the ratio of the components included in the "Inspiration" and "Inspiration plus" drinks. The practical value of the work lies in the development of drinks that have health and preventive properties and therefore can be used for consumption by people of different age categories to replenish the body with biologically active substances. The use of fructose syrup instead of sugar syrup allows people with diabetes to consume such drinks.

Hydration Processes in HCl and Aqueous Salt Solutions

In this work, the number of hydration of ions (K+ and Cl-, K+ and Br-, K+ and I-, H+ and Cl-, Li+ and Cl-, Cs+ and Cl-, Na+ and Cl-) in dilute aqueous solutions of some electrolytes of KCl, KBr, KI, HCl, LiCl, CsCl, and NaCl was studied by the proposed refractometric method. Further, the effect of polyethylene glycol (PEG-6000) on the hydration processes for ions in aqueous solutions of KCl and KBr was studied. It turned out that when the polymer is introduced into the solution, the hydration numbers of ions decrease, which is apparently due to the role of the PEG oxygen atom competing with ions in interaction with water molecules.

Kinetics of bis(2‐methyl) butylene carbonate by transesterification of dimethyl carbonate with 1,4‐butanediol

AbstractThe kinetic behavior of bis(2‐methyl) butylene carbonate (BMBC) by the transesterification of dimethyl carbonate (DMC) with 1,4‐butanediol (BDO) was investigated experimentally and theoretically. The Fourier transform infrared spectroscopy (FTIRs) test confirmed that the BMBC was successfully synthesized. The optimum preparation process of BMBC was investigated at atmospheric pressure, where Zn(Ac)2∙2H2O was the best catalyst for this transesterification reaction, and the optimal concentration was 0.3 wt%. The conversion was determined by measuring the amount of methanol produced during the reaction by refractometric method. A kinetic model was proposed according to the experimental results. The results showed that the transesterification reaction was a pseudo‐first‐order reaction. The apparent activation energy (Ea) significantly decreased with the increase of catalyst concentration from 0.1 wt% to 0.5 wt%. The Ea of the reaction was 102.13, 84.36, and 70.18 kJ mol−1, respectively, when the catalyst concentration was 0.1 wt%, 0.3 wt%, and 0.5 wt%. Furthermore, the parameters of the optimal heating curve in the batch reactor was obtained according to the optimal model.

Morphological criteria for identifying coronavirus infection in companion animals

Due to the high level of urbanisation in Ukraine, during the years 2021-2023, there is a tendency for a rapid increase in the number of companion animals in large cities – dogs and cats. Humanity has not yet finally eliminated the SARS-CoV-2 coronavirus pandemic, as world scientists have established the involvement of these animals in its spread, which causes concern among specialists and requires a comprehensive investigation. The purpose of the scientific study was to determine marker changes in haematological parameters and haematopoiesis parameters under the influence of coronavirus infection in dogs and cats. For this purpose, spectrophotometric and refractometric methods of haematological studies were used: morphological and biochemical parameters of blood, the functional state of erythro- and leukocytopoiesis. Considering changes in blood morphological parameters, the main parameters of the identity of the pathogenic effect of coronavirus on the body of dogs and cats were established, namely: a decrease in the number of lymphocytes, glucose content, and protein coefficient. There was a significant increase in the activity of alkaline phosphatase in the blood and α-amylase, the content of total bilirubin, and the erythrocyte sedimentation rate. In particular, it has been experimentally established that the use of leukocyte indices increases the information content of the general blood test for coronavirus infection, and additional analysis of integral changes based on leukocyte blood parameters allows determining not only the state of reactivity of the body, but also the extent of endogenous intoxication. The results of changes in blood morphological parameters are somewhat comparable to those in humans, which indicates the need for an in-depth study of the genetic potential of coronavirus pathogens in companion animals and humans at the molecular and biological levels. Experimentally determined marker changes in haematological parameters for coronavirus infection in dogs and cats can be useful for its timely diagnosis and prediction of the severity of the disease

On the use of two emerging laser-based flaw-detection techniques – Considerations and practicalities

The pursuit of non-contact techniques for detecting ultrasonic waves propagating on the surface of solids is stimulated by the possibility of gaining some advantages over conventional contact methods. Non-contact methods are becoming a milestone in performing non-destructive evaluation in several industrial fields, where hazardous environments, narrow spaces, high temperatures, and complex geometries are encountered. Such methods exploit photo-acoustic interactions between light and sound waves. This work compares two non-contact laser-based methods for detecting artificial flaws of different sizes in metallic specimens. It uses multi-signal homodyne interferometry and single beam deflectometry to record the ultrasonic waves produced by a piezoelectric probe capable of generating surface Rayleigh waves. The results were analysed in both time and frequency domains. Moreover, the signal-to-noise ratio was evaluated for both measurement systems by changing the distance between the defect and the point where the signals were collected. The results show the main differences between the two techniques and the practicalities associated with their usage. The employed refractometric method has a lower sensitivity to surface roughness than the interferometric method. On the other hand, the interferometric technique allows for higher spatial resolution, wider frequency bandwidth and a higher detectable frequency (i.e., detecting low-sized defects).

Express-analysis of wastewater using a fibre-optic measuring transducer

The application of optical methods of wastewater quality determination is substantiated, among which the most widespread are refractometric methods based on refractive index measurement. The known methods of wastewater refractive index measurement require considerable hardware and time costs, have low reproducibility of measurement results. The proposed fibre-optic measuring transducer, which implements a new refractometric method, the main elements of which are supply and return optical fibres, between which there is a tube, inside of which there is an analyzed liquid. The application of the proposed measuring transducer contributes to the acceleration of the process of express analysis of wastewater.

ՕՐԳԱՆԱԿԱՆ ՄՇԱԿՈՒԹՅԱՆ ՊԱՅՄԱՆՆԵՐՈՒՄ ԱՉՔԵՐՈՎ ԲԵՌՆՎԱԾՈՒԹՅԱՆ ԱԶԴԵՑՈՒԹՅՈՒՆԸ ԽԱՂՈՂԻ ՍԵՎ ԱՐԵՆԻ ՍՈՐՏԻ ՀԱՍՈՒՆԱՑՄԱՆ ԴԻՆԱՄԻԿԱՅԻ ՎՐԱ

The aim of the work is to study the growing dynamics of total sugars, acids and phenolic compounds (flavonoids, anthocyanins) in Sev Areni grape berries in conditions of organic farming depending on the buds’ load rate. The studies were conducted in 2020-2021. The vineyard belonging to “Hin Areni” CJSC, established in 2007-2008, is located in the Areni community of Vayots Dzor marz, at an altitude of 1200 m above sea level. At the start of the trials, 5 hectares of the garden (10 ha) were cultivated with organic methods. The experiments were carried out in four replications through the method of Lazarevskiy including 15 vines in each option. The dynamics of berry ripening was studied according to vine load. Sugar content (refractometric method), titratable acidity (using OIV-MA-AS313-01 method), pH, total phenolic content of fruit juice was determined three times. According to study results, the amount of flavonoids and anthocyanins changes during grape ripening, depending on the vine load. Along with the grapes maturation, sugar content of the fruit juice increases, the acidity decreases. However, parallel to the increase in vine load, the sugar content decreases. In the option of 50 bud load the sugar content decreases. The harvested yield lags behind the option of 30-40 bud load in its qualitative properties. Thus, it is not recommended to use high bud loading option in the organic farming. Based on the study results, it is recommended to use 30-40 bud vine loads of Sev Areni variety in conditions of vineyards organic farming.

Thermophysical and chemical characteristics of tropical fruits

When developing canning technologies raw material processing processes thermophysical calculations are inevitably used. This work's purpose is to analyze the tropical fruits thermophysical characteristics. The research objects were the following fruits: kiwi, papaya, avocado and figs. The stationary flat layer method was used to analyze the thermal conductivity. The cryoscopic temperature was determined by the thermogram flat surface which was obtained during the product freezing. The hydrostatic weighing method was used to determine the density. The sugar content was determined using the refractometric method. The moisture content was determined by drying-out to a constant mass. As a result of the carried out work, the physical and chemical parameters of kiwi, avocado, papaya and figs were determined. The thermophysical properties of tropical fruits such as heat capacity, cryoscopic temperature, thermal conductivity, and the amount of frozen moisture, were calculated.

The prospects of using apples and pears to obtain biologically active substances

Relevance. Apples and apple juices are healthy food products with a large amount of biologically active substances. The polyphenols contained in them are powerful natural antioxidants. They prevent the development of many chronic heart diseases and have many pharmacological properties. Thus, polyphenols increase the resistance of blood vessels, improve blood circulation, protect elastin and collagen fibers, and serve as fundamental elements supporting skin tissues. Apples contain such practically valuable substances as pectins. At the same time, in fresh apples, protopectin prevails over soluble pectin and makes up 52.3– 97.0% of the total amount.Methods. The objects of the study were the fruits of apple varieties: Voskhod, Talgar Bayterek, Sarkyt and Saya, as well as pear varieties: Bostandyk, Nagima, Sylyk, Zhazdyk. The fruits of apples and pears were harvested from September to mid-October 2021 in Saryagash district, in the farm "Tenge". Experimental data were obtained in the laboratory of the South-Kazakhstan University named after M. Auezov. At the first stage of the study, the quality of apples was determined in accordance with the requirements of GOST R 54697–2011. At the second stage, physico-chemical parameters were determined according to standard methods. The content of soluble solids was determined by the refractometric method using a refractometer, at ambient temperature 20±0.5 °C, The mass fraction of dry substances was determined by the refractive index. The sum of sugars — according to the Bertrand method.Result. Studies have established that the fruits of all studied varieties of apples and pears grown in Kazakhstan, according to organoleptic and physico-chemical indicators, contain high levels of chemicals and phenolic compounds, but the most valuable source of biologically active substances were apples of variety Baiterek and pears of variey Zhazdyk.

Source material creation for high content of dry soluble substances F&lt;sub&gt;1&lt;/sub&gt; cherry tomato hybrids breeding

Relevance. Consumer demand development of exotic colors presence in modern tomato hybrids requires a timely response from domestic breeders for creating highly effective hybrids. With regard to cherry tomatoes, special attention of breeders is aimed at achieving excellent taste in new hybrids. One of the indicators is the "content of dry soluble substances in fruits". However, there is no information in the literature about the variation of this trait within different color groups of cherry tomatoes. The aim of our work was the creation of initial material for the selection of F1 cherry tomato hybrids with a high content of dry soluble substances.Materials and methods. All measurements were obtained by the refractometric method and presented in the oBrix scale. The study examined 46 F2 splitting cherry tomato populations, including 17 red, 12 yellow, 7 pink, 8 brown, and 2 purple. Analyzing the obtained data, the following statistical indicators were made: the frequency of occurrence of the variant; arithmetic mean; dispersion; the coefficient of variation; sample mean error. Relative error was used to test the sample results obtained.Results. The coefficients of variation of the trait «content of dry soluble substances in fruits» were calculated in each of the five color groups of cherry tomatoes (from 17.43% for brown-fruited to 25.13% for red-fruited). The boundaries of variability and average values of the content of dry soluble substances were determined both within the groups (from 7.2 oBr in pink-fruited to 8.8 oBr in yellow-fruited ones), and for each studied breeding sample. The practical result of the work was selection of the most promising breeding material within different color groups of cherry tomato, combining high values of dry matter with a complex of economically valuable traits.

The use of zeolite 13X as a stationary phase for direct determination of water in organic solvents by high-performance liquid chromatography

High-performance liquid chromatography (HPLC) method for direct determination of water impurities in various organic solvents using a column (50 × 4.6 mm, ID) packed with 5 μm faujasite and methanol as an eluent was developed. Detection of the water peaks was performed by using either refractometric or indirect spectrophotometric method at 204 nm. In the first case the limit of detection (LOD) and limit of quantitation (LOQ) were 0.001 wt% and 0.0033 wt%, respectively for a sample volume of 20 μL. A linear calibration plot (R2 = 0.9998) for the water content between 0.01 and 9.55 wt% was obtained. The developed method was applied for the direct analysis of various polar organic solvents including acetonitrile, nitromethane, 1,4-dioxane, 2-ethoxyethanol, methanol, dimethyl sulfoxide (DMSO), ethanol and 2-propanol.

Magnetoplasmonics beyond Metals: Ultrahigh Sensing Performance in Transparent Conductive Oxide Nanocrystals.

Active modulation of the plasmonic response is at the forefront of today's research in nano-optics. For a fast and reversible modulation, external magnetic fields are among the most promising approaches. However, fundamental limitations of metals hamper the applicability of magnetoplasmonics in real-life active devices. While improved magnetic modulation is achievable using ferromagnetic or ferromagnetic-noble metal hybrid nanostructures, these suffer from severely broadened plasmonic response, ultimately decreasing their performance. Here we propose a paradigm shift in the choice of materials, demonstrating for the first time the outstanding magnetoplasmonic performance of transparent conductive oxide nanocrystals with plasmon resonance in the near-infrared. We report the highest magneto-optical response for a nonmagnetic plasmonic material employing F- and In-codoped CdO nanocrystals, due to the low carrier effective mass and the reduced plasmon line width. The performance of state-of-the-art ferromagnetic nanostructures in magnetoplasmonic refractometric sensing experiments are exceeded, challenging current best-in-class localized plasmon-based approaches.