Blue cheeses owe their distinctive texture, flavor, and aroma to Penicillium roqueforti. Understanding the technological traits and secondary metabolite production of this species is essential for cheese quality and safety. Here, 20 P. roqueforti isolates from traditional Turkish blue cheeses, including Tulum and Civil, were evaluated for growth at different temperatures, salt tolerance, proteolytic and lipolytic activities, and production of mycophenolic acid (MPA) and roquefortine C (ROQC). Marked strain-level variation was observed. Hierarchical clustering and principal component analysis grouped the isolates into three clusters. Civil cheese isolates showed improved growth under temperature and salt stress and produced lower ROQC than Tulum isolates, suggesting adaptation to distinct cheese environments. Selected isolates were tested in model Tulum cheeses, where all successfully colonized and formed blue veins. Secondary metabolite levels in cheese were low. These results highlight the diversity of Turkish P. roqueforti isolates and support the development of cheese-specific starter cultures.
This study characterized a novel extracellular acid protease from Lacticaseibacillus paracasei (APLP) and evaluated its potential as a milk-clotting enzyme for cheese making. APLP was purified by heat treatment, ammonium sulfate precipitation, and size-exclusion chromatography, yielding a 30 kDa enzyme that showed effective milk-clotting activity at pH 6 and 35 degrees C, despite optimal proteolytic activity at pH 8.5 and 50-75 degrees C. Under equal-volume conditions (1 mL enzyme extract per 10 mL milk), APLP achieved flocculation in 71 s, substantially faster than the commercial comparator Presurpara 1/5000 (484 s). Coagulation activities were 13.9 PU/mL versus 2.04 PU/mL, respectively. APLP also exhibited superior specific activity (8.74 PU/mg) and coagulation power (1/42,810) compared to Presurpara 1/5000 (1.17 PU/mg and 1/25,196, respectively). A prototype cheese (Lacticop) produced with APLP and enriched with rosemary received favorable sensory evaluation scores. These findings indicate that APLP is a promising microbially derived coagulant for large-scale cheese production.
Calcium carbonate (CaCO3) addition to milk represents a promising approach to reduce phosphorus bioavailability in cheese for consumers with impaired renal function, but no data is available on the structural, sensory characteristics of cheese. This study evaluated the effects of CaCO3 supplementation (2 g/L) on physico-chemical, structural, sensory properties of Caciotta cheese. CaCO3 significantly increased cheese porosity, likely due to CO2 release under mildly acidic conditions, while textural and rheological properties were unaffected. Low-field NMR relaxometry revealed reduced proton relaxation times in specific water populations, suggesting altered water-protein interactions for CaCO3-enriched cheese. Sensory analysis indicated slightly lower but positive consumer acceptability scores for CaCO3-enriched cheese, mainly related to appearance and flavor, whereas texture perception remained unchanged. Overall, CaCO3 supplementation enabled the production of nutritionally functional Caciotta cheese preserving satisfactory structural and sensory quality. These findings provide useful insights into the development of dairy products targeted at special nutritional needs.
The current study aims to understand the contribution of koku-active substances such as gamma-glutamyl peptides and volatile compounds to the overall perception of koku-related sensory properties using multivariate statistical analysis. Specifically, we examined blue-mould, smear-ripened and hard yellow type cheeses and cheese powders. The results highlighted blue-mould cheese and cheese powder among other cheese types, showing the highest diversity and quantity of gamma-glutamyl peptides. Among the seven different measured kokumi peptides, gamma-Glu-Thr and gamma-Glu-Glu showed the strongest correlations with koku-related descriptors such as mouthfulness, richness, and persistence of aftertaste. Volatile markers, including esters, alcohols, terpenes, and sulfur compounds, were strongly linked to sensory attributes typically associated with smear- and blue-mould-type cheeses, such as 'smear flavour', 'blue cheese culture', or 'mouldy'. These findings confirm the synergistic role of gamma-glutamyl peptides and volatiles in shaping flavour complexity and koku perception. The proposed multivariate framework offers a robust tool for guiding formulation strategies in cheese-based products.
This study investigated the surface characteristics and the rehydration behavior of sodium caseinate powder obtained from camel and bovine milk (CMSCP, BMSCP, respectively). Both powders exhibited similar total fat and ash contents, whereas CMSCP contained slightly lower protein and higher lactose quantity than BMSCP. Despite having comparable fat content, the X-ray photoelectron spectroscopy indicated that CMSCP exhibited greater surface fat (48.9 +/- 2.4%) and lower protein (50.4 +/- 2.5%) contents than BMSCP. This highlighted the hydrophobic nature of CMSCP surface which was confirmed by its higher C/O ratio (5.6 +/- 0.3). FT-IR spectroscopy confirmed the structural differences between both powders. CMSCP displayed strong hydrophobic protein-protein interaction and a higher beta-sheet structure, as well as a unique glycerol-casein band at 1037 cm-1, indicating the development of insoluble aggregates. Such protein aggregations, surface fat coverage and surface hydrophobicity deeply reduced the rehydration behavior of CMSCP which was confirmed by the turbidity measurements.
Methicillin-resistant Staphylococcus aureus (MRSA) is an important dairy-safety concern because of its antimicrobial resistance, biofilm-forming capacity, and persistence in milk systems. This study evaluated the cell-free supernatant (CFS) of bovine-derived Loigolactobacillus coryniformis XJ-C-L1 as a natural strategy for controlling MRSA in dairy matrices. XJ-C-L1 CFS produced an inhibition zone against a raw-milk-derived MRSA isolate, showed antibacterial activity against selected foodborne bacteria, suppressed microbial growth, and reduced biofilm biomass and thickness. In pasteurized milk, CFS inhibited MRSA at 4, 25, and 37 degrees C, achieving a maximum reduction of 4.24 +/- 0.20 log CFU/mL. Time-kill analysis confirmed concentration-dependent inhibition, with 2 & times;MIC reducing viable cells to undetectable levels after 24 h. The activity was heat-stable and protease-insensitive but disrupt after pH neutralization. Integrated metabolomics, genome annotation, pHmatched validation, and lipid-compound assays supported an acid-dependent, metabolite-associated activity basis. These findings support XJ-C-L1 CFS as a promising antimicrobial candidate for improving MRSA control in milk.
The aim of this study was to evaluate the effect of prolonged ripening(0-72 months) on the physicochemical, rheological, and microstructural properties, as well as consumer evaluation, of Bursztyn cheese. Extended ripening resulted in progressive moisture loss and increased dry matter content. Texture profile analysis revealed an increase in hardness up to 24 months of ripening. The storage(G ') and loss(G '') moduli increased with ripening time, whereas meltability and water activity decreased. MIR spectroscopy confirmed ongoing biochemical transformations related to proteolysis and lipolysis. Optical and confocal microscopy demonstrated progressive structural heterogeneity and crystal accumulation. XRD analysis identified brushite in the 72-month-ripened cheese. Consumer evaluation indicated that cheese ripened for 36 months exhibited the most balanced sensory profile, whereas the 72-month-ripened cheese showed highly intense sensory attributes appreciated mainly by cheese connoisseurs. The results demonstrate that prolonged ripening strongly influences cheese functionality and may support the production of premium long-ripened cheeses.
This paper examines errors in recovering (radio diagnostics) solar flare parameters (magnetic field, accelerated electron density, etc.) by fitting microwave spectra. The analysis was performed by diagnosing two model radio sources with known preset parameters, including given parameters of the pitch-angle anisotropy of emitting electrons. The diagnostics was carried out by a genetic minimization algorithm. It is shown that using the traditional approach on the assumption about isotropy of pitch angular distribution of electrons leads to significant systematic errors, in particular, to a strong underestimation of the magnetic field strength in the presence of longitudinal anisotropy of pitch angular distribution of electrons in a real radio source. When restoring the same parameters in view of possible anisotropy, the accuracy of the restoration increases markedly.
A mathematical model of the quasi-static electric field in the surface air layer in the sensor installation area is constructed with regard to its design and placement in a forest glade. The calculations are performed for the conditions of the Paratunka Geophysical Observatory. The model takes into account the influence of the contours of the glade, the height of the surrounding forest, and changes in the height of the snow cover in winter on measurements of the electric field. We calculate the calibration coefficients for the measurements, which should be used to eliminate distortions of the atmospheric electric field introduced by the measuring system.
This work focuses on exploring the correlation between solar activity parameters and geomagnetic activity during solar cycles 23 and 24. The analysis includes variables such as solar wind speed VSW, proton density Np, solar wind dynamic pressure PSW, and interplanetary magnetic field components Bz and By, along with energy-related parameters ESW, dφ/dt, ε. Correlation coefficients and time lags were calculated between these solar wind, magnetic field, and energy parameters and geomagnetic indices SYM-H, AE for storms driven by CME and CIR. The analysis of time delays ∆t of auroral activity relative to the energy parameters and the interplanetary magnetic field component Bz for storms of both types has revealed durations ranging from 30 to 60 min, whereas for the ring current the delays ranged from 6 to 24 hrs.
This paper examines scientific and technical requirements for a specialized radio telescope which allows us to make a space weather forecast from observations of radio sources that scintillate on moving irregularities of interplanetary plasma. It is shown that in addition to forecasting the radio telescope can solve other scientific problems. A variant of the antenna's technical implementation is proposed, and the structure of the radio telescope is studied. The radio telescope is a spaced antenna array consisting of modules, each with 16 (4×4) base antenna elements representing 2 orthogonal dipoles. The effective area of a module is 16 m2 at the central frequency of 180 MHz; the total operating frequency band is 120–240 MHz. The module’s field of view is at least 400 sq.deg. in the range ± 50° from the zenith at the central frequency. The sensitivity drops by a factor of 2 at the edges of the field of view. It is demonstrated that the telescope consisting of 64 modules will provide a forecast at least 2–3 times a day. The estimated accuracy of predicting the arrival time of coronal mass ejection at Earth is one hour.
This paper presents modern digital signal conversion systems used for radio telescopes of the Quasar VLBI network. We briefly trace the evolution of signal conversion equipment from analog and hybrid solutions to a multifunctional digital backend system (MDBE) providing fully digital processing of received signals over a wide frequency range. The architecture, main technical characteristics, and operating modes of MDBE are described, along with specific features of its application on the RT-13 and RT-32 radio telescopes. It is shown that the use of MDBE enables unification of signal conversion hardware, supports both broadband and narrowband very long baseline interferometry modes, and allows spectral and radiometric observations to be implemented within a single hardware–software platform. We give examples of practical applications demonstrating the system’s efficiency, stability of signal path parameters, and compatibility with national and international data recording and transmission standards. Prospects for further development of the system and expansion of the range of scientific and applied problems are also discussed.
The response of the mid-latitude atmosphere to Forbush decreases in galactic cosmic rays is analyzed. We use the results of long-term observations of cosmic ray variations and changes in atmospheric parameters at seven mid-latitude cosmic ray stations for the period from 1966 to 2024. During Forbush decreases (at the decline and minimum of intensity), an increase in atmospheric pressure is observed at all mid-latitude cosmic ray stations. When the cosmic ray intensity is restored after a Forbush decrease, the pressure decreases. The duration of this atmospheric response coincides with the duration of the Forbush decrease. The effect is more pronounced in the cold season, as well as for cosmic ray stations with small geomagnetic cutoff rigidity values. Variations in mean mass and surface temperatures during a Forbush decrease are observed at all cosmic ray stations and differ significantly for the cold and warm seasons. The obtained results suggest that changes in cloudiness and atmospheric transparency caused by changes in the ionization rate during Forbush decreases are a possible cause of the observed effects.
The NVGRC catalog includes objects selected by the pattern recognition algorithm from the NVSS survey as candidates for giant radio sources (GRS). We have studied in detail 370 NVGRC objects falling within the right ascension interval 00h00m–05h20m to confirm their GRS classification. The GLEAM, TGSS, RACS, and VLASS radio surveys were used to determine the radio morphology of the NVGRC objects; the LS, DES, UKIDSS, and WISE optical and infrared surveys, to identify their host galaxies; and the VizieR, NED, and NOAO DataLab databases, to determine their redshifts. This work would not have been possible without the information resources and software of the virtual observatory. Of the 370 NVGRC objects examined, 187 radio sources were classified as GRSs; 82 of them were previously known as GRS from publications. We have confirmed for the first time that 105 NVGRC objects are GRS. For 98 objects it turned out that their components were not physically connected and were merged into one radio source by a pattern recognition algorithm. We estimated the efficiency of the algorithm, used for selecting GRS candidates for the NVGRC catalog, at ≈30 %.
The paper presents the algorithm for evaluating parameters of coherent scattering signals, which is based on the assessment of their parametric spectra by the well-known autoregression ARMA(10,10) model. The assessment consists of autoregression over 10 sequence members, moving average over residuals for 10 sequence members, and subsequent fitting of the resulting spectra with the sum of gaussian functions. The algorithm is a development of Burg’s method, previously proposed for the analysis of SuperDARN data. It differs from the method in the use of a more complex regression model, consideration of characteristics of the correlation function, and determination of three parameters for each peak (mode) — amplitude, Doppler velocity, and spectral width. Comparison shows that the best continuity between the parameters of multi-mode signals, obtained by new and standard signal processing methods, is provided by analysis of the mode with maximum integral power. The analysis has revealed that new and standard methods in the case of single-mode signals give close Doppler velocities. The multi-mode analysis presented in the paper increases the number of detected signals of various types, and can be employed to expand the diagnostic capabilities of SECIRA/SuperDARN radars, including automatic classification of each mode.
This study is based on observations of the atomic oxygen airglow emission at 630 nm obtained with a Fabry—Perot interferometer (FPI) of the National Heliogeophysical Complex. FPI is installed in the Geophysical Observatory of the Institute of Solar-Terrestrial Physics SB RAS (Tory, 52° N, 103° E). Doppler shifts of the emission line were measured and then converted into horizontal wind velocities along the zonal and meridional directions during nighttime and twilight periods. We analyze the seasonal variability of neutral wind components during 2022, using both FPI measurements and model calculations from three versions of the Horizontal Wind Model: HWM93, HWM07, and HWM14. The analysis covers local nighttime hours (10–24 UTC). The data was separated by seasons relative to solstices and equinoxes and filtered by cloud conditions. The discrepancies between modeled and observed wind components vary with both local time and season. None of the HWM versions provide acceptable agreement with the measurements, indicating that HWM outputs for the Baikal region should not be considered accurate. The results of this study can be used to develop recommendations for improving or adjusting HWM in order to better describe the dynamics of the upper atmosphere in the region. These findings are also useful when choosing the most suitable HWM version for estimating a specific wind component in a given season.
The paper analyzes variations in the maximum electron density of the F2 ionospheric layer (NmF2), using data from the Tomsk ionospheric station for the period from 1947 to 2024, including seven 11-year solar cycles, with the aim of identifying seasonal changes in daily NmF2 maxima in the mid-latitude ionosphere and their relationship with solar activity. Seasonal-daily variations of NmF2 were constructed separately for low and high solar activity levels. Linear and quadratic models of the regression dependence of the NmF2 daily values on the F10.7 index are calculated for each month of the year. Regression models are computed for both monthly medians and daily data. Quantitative comparisons and resistance factors of different models for different types of data aggregation are given.
For radio interferometers, antenna pointing accuracy is critical, as deviations in the direction of the beam from the source not only reduce the signal level, but also lead to incorrect measurements of visibility phases. These distortions cannot be corrected during data processing and reduce the dynamic range of images. The measurement method involves determining the deviation of the beam from the center of the Sun for different azimuth and elevation angles and fitting the resulting dependence using a model developed for altazimuth mounts. The model allows us to determine the deviation of the mount axis from the zenith direction, the non-orthogonality of the azimuth and elevation axes, the azimuth offset of the feed, and the azimuth and elevation constants. Mechanical adjustment of these parameters with the specified accuracy is impossible, so the correction was performed by introducing corrections to each moment in time for each antenna. Using the described technique, we managed to achieve an antenna pointing accuracy of approximately 2 arcmin.
The eruption of a large prominence and the resulting development of a coronal mass ejection (CME) were observed on June 12, 2023 by the Siberian Radioheliograph in microwaves up to heliocentric distances exceeding two solar radii, space-borne telescopes in the extreme ultraviolet, and coronagraphs in white light. The evolution of the CME structural components was traced and their kinematic characteristics were measured. The CME components underwent two successive acceleration pulses, comparable in magnitude and duration. According to the observations, the first acceleration pulse was caused by torus instability of the magnetic flux rope associated with the prominence. At this stage, its expansion was self-similar and consistent with the expansion of the CME frontal structure. The frontal structure was an expanding arcade that encompassed the pre-eruption prominence. The second acceleration pulse was associated with helical kink instability, which manifested itself in the deformation of the top of the erupting prominence, visible as a helical protrusion. The development of helical kink instability affected the motion of the CME frontal structure, but did not influence the motion of the main body of the CME core, shown up as the massive part of the erupting prominence beneath the helical protrusion. After the completion of the helical kink instability, the coordinated self-similar expansion of all CME components recovered. The fact that the helical kink instability occurred much later than the torus instability excludes its involvement in causing the latter, as has sometimes been assumed.
If we consider the auroral oval as an indicator of the electrojet position, the information about the position of its equatorial boundary allows us to predict the latitudes at which the most intense geomagnetic variations can be observed. These variations are the source of geomagnetically induced currents (GICs), which pose a threat to the stable operation of electric power systems. The Starkov-93 (S93) model, Auroral Precipitation Model (APM), and OVATION Prime (OP) model are widely used to estimate the possible minimum latitude of the oval. However, the databases with the aid of which these models were built did not contain rare extreme magnetic storms (|Dst|>400 nT). As a source of information on auroral latitudes during extreme storms, we employ the statistical model of the minimum latitude of the equatorial boundary of discrete auroras L2025, which is based on observational evidence. Extrapolation of the dependences of the oval’s equatorial boundary latitude on the storm intensity obtained by the S93 model and APM during extreme storms (|Dst|>400 nT) diverge from the predictions of the L2025 model. In the new version of APM (APM_GEO), the limitations to the magnetic activity level in the AL and Dst indices were removed, which makes it possible to estimate the location of the precipitation boundary during super substorms and extreme storms. To compare the OP model with APM_GEO, we have examined the dynamics of the auroral oval during the May 10–11, 2024 magnetic storm and have constructed maps of the position of the oval equatorial boundaries for different storm phases for the territory of the Russian Federation. As revealed from the comparison with APM_GEO, the OP model driven by interplanetary medium parameters significantly underestimates latiudinal shift of the oval. Since intense substorms during storms lead to a significant equatorial shift of the oval boundary, all large energy grids of the be affected by GICs not only during extreme, but also during strong magnetic storms in the presence of intense substorms against their background.
