Abstract Catalytic styrene Ph—CH=CH 2 oxidation is assumed to be a simple reaction procedure; however, its details require further systematic research. Using quantum-chemical treatment, relevant intermediates have been investigated in various charge and spin states of alternative reaction pathways of styrene oxidation by hydroperoxyl using the [CuL] − catalyst, where H2L = trans -2,9-dibutyl-7,14-dimethyl-5,12-di(4-methoxyphenyl)-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione. Within reaction pathway A, the neutral hydroperoxyl radical is bonded to Cu to form 2 [CuL(OOH)] – . Subsequent addition of neutral styrene results in the formation of 2 {[CuL(OH)](Ph—CH 2 —CHO)} – . Reaction pathway B starts with the initial non-radical formation of the π-complex 1 [CuL(Ph—CH=CH 2 )] − which is problematic due to its endothermic character. Subsequent addition of a hydroperoxyl radical leads to 2 {CuL[Ph—CH(OOH)—CH 2 ]} − and its oxidation leads to the separation of Ph—CH(OOH)—CH 2 . The exothermic reaction path A is preferred over the endothermic reaction path B.

Abstract This work provides a systematic theoretical study on gas-phase bond dissociation enthalpies for homolytic C—H bond cleavage in linear and branched alkanes. Quantum chemical calculations were performed using the density functional theory (DFT) and ab initio composite (G4(MP2), G4) methods. In case of DFT calculations, the M06-2X and B3LYP functionals combined with 6-311++G**, aug-cc-pVDZ, aug-cc-pVTZ, and aug-cc-pVQZ basis sets were covered. In linear molecules, the best agreement with experiment was observed for B3LYP/aug-cc-pVQZ. In both composite approaches, as the number of C atoms increases, the BDE values are affected by the systematic error of the method. For example, G4 BDE of terminal —CH3 group of hexane is 422.6 kJ·mol−1 while for undecane it is 415.5 kJ·mol−1. On the contrary, the composite methods are in better agreement with experiments compared to the DFT approaches for simple branched hydrocarbons.

Abstract Aflatoxin M 1 (AFM 1 ), which is a hydroxylated metabolite of aflatoxin B 1 , can be irreversibly bound to casein micelles and thus, its higher content is measured in cheese than in the original milk. The present study describes validation of a reliable and rapid method for AFM 1 content determination in cheese applied to 36 kinds of cheese sold in Slovakia during the spring of 2024. The method consisted of three basic steps: extraction of AFM 1 from cheese, purification of extracts using immunoaffinity columns, and determination of AFM 1 content by high performance liquid chromatography with fluorescence detection. Suitability of the method was proved by the limits of detection and quantification equal to 2.0 and 6.0 ng/kg, respectively, which is in accordance with the limits set by European legislation for analytical procedures for AFM 1 determination in milk. Accuracy of the method was determined using a recovery test, spiking cheese with AFM 1 , and varied between 87.8 and 100.5 %. Precision was confirmed by low relative standard deviations, 0.3—7.9 %, and Hor- Rat values (0.01—0.32) of the results obtained on different days. Experiments showed the AFM 1 content in all cheese to be below the limit of quantification, which indirectly confirmed the absence of AFM 1 in milk as raw material. However, AFM 1 contamination of milk is expected to increase due to global warming in future; therefore, AFM 1 contamination should be an essential part of current food safety issues.

Abstract The logarithm of octanol-water partition coefficient (log P) is estimated by means of six parametric methods (iLOGP, XLOGP3, WLOGP, MLOGP, SILICOS-IT, OBLogP) and six quantum mechanics (QM) based models. QM models comprise DFT functional choice (B3LYP, M06-X, PBE0, including the xTB parametrization variant), implicit solvent model choice (IEFPCM, SMD, or ALPB), and basis set quality in DFT calculations (6-31G* and 6-311++G**). Several statistics are evaluated to compare Clog P estimates to experimentally measured dataset of 36 molecules picked from Meylan and Howard J. Pharm. Sci. 84 (1995) 83—92. ChemmineR cluster analysis has been performed to confirm structural diversity of molecules in the employed molecular dataset. XLOGP3 performance is the best among all the methods used, while SMD based DFT models showed a clearly competitive results with the remaining parametric methods irrespective of DFT functional or basis set quality.

Abstract Aggregation of proteins naturally occurs during different stages of cultivation and downstream processes and is often associated with quality reduction in the final product. Therefore, determining the presence of aggregates is important. In this study, a fluorescence-based analytical method using the dye Nile red was developed for antibody aggregates quantification. The fluorescence assay demonstrated selectivity and sensitivity towards hydrophobic surfaces of aggregates within reliable quantification range of 0.0165—1.65 g/L. Validation confirmed high reproducibility, with intra-assay and inter-assay coefficients of variation within acceptable limits. The dye was stable in commonly used buffer systems and in the presence of salts. Comparative analysis of SEC and fluorescence methods indicated that fluorescence detection remains sensitive to aggregation beyond SEC’s detection threshold. Thermal stability studies revealed that polyclonal antibodies have higher resistance to thermal stress than monoclonal antibodies, which suggests that structural variability plays an important role in thermal stability. Additionally, antibody aggregation was shown to be pH-dependent, with increased aggregation at both low and high pH levels. Polyclonal antibodies were stable at pH 5—6. In more acidic conditions, soluble aggregates were formed, while at neutral and basic pH, aggregation was accompanied by the formation of insoluble particles. The effect of salts on aggregation was variable, with NaCl promoting aggregation at high concentrations, NaSCN facilitating dissociation of aggregates, and Na2SO4 inducing precipitation. Guanidine HCl exhibited a stabilizing effect, preventing aggregation over time.

Abstract This work focuses on the influence of solid-state fermentation on the polyphenols and flavonoids conent in fruit pomace of apple, aronia, and sea buckthorn. A comparison was made during a seven-day fermentation of pomace with A. niger and with autochthonous microflora, showing that this method has no significance for aronia and sea buckthorn pomace. Autochthonous microflora had a more favorable effect on the content of polyphenols and flavonoids than A. niger. However, in the case of apple pomace, the content of total polyphenols increased up to 1425 mg GAE/100 g DW on the seventh day of fermentation with A. niger, representing a 7.3-fold increase compared to the initial value of 195 mg GAE/100 g DW. Our results therefore present an attractive way of agro-waste utilization and the subsequent implementation of these isolates in other types of industry.

Abstract Microbial growth responses of probiotic Lacticaseibacillus rhamnosus GG with well-documented health effects were studied in an oat-based milk alternative in the biokinetic temperature range of 8 to 44 °C. The applied Baranyi model (with a fixed parameter value h0 = 0.407) fitted the growth data well, as shown by the goodness of fit measures (R2 = 0.995; RMSE = 0.153) for the total experimental data set (n = 245). Using the initial inoculations of 2.7 ±0.1 log CFU.ml−1, the maximal population density (MPD) of 8.3 ±0.4 log CFU. ml−1 was reached in stationary phase in the temperature range from 12 to 37 °C. Slightly lower MPDs were recorded at higher temperatures, 40 and 44 °C, while an increase in only 1 log was reached at 8 °C. Thus, the MPD 3.7 log CFU.ml−1 was only estimated. Based on the experiments, the highest specific growth rate (μmax ) of 0.800 −1 and the shortest lag phase (λ) of 0.51 h were observed at 40 °C. The Ratkowsky modified square root model (mSQRT) was used in the secondary modelling for μmax values and the cardinal parameters minimum and maximum temperature were determined: Tmin = 4.2 °C; Tmax = 47.8 °C. As drinks of plant origin are produced in large volumes, the production of their fermented varieties is expected to appear in a short time. This is why providing parameters on kinetic behaviour of L. rhamnosus GG is essential for industrial process design and further scale up of fermented dairy-free matrice with probiotic potential.

Abstract In this work, theoretical and experimental study of monoethanolamides (MEAD) and diethanolamides (DEAD) is presented. The aim was to investigate the thermodynamics of addition reactions used in the synthesis of MEAD and DEAD. The reactions have exothermic character and alkyl elongation affects the reaction enthalpy of DEAD production reactions. In the experimental part, the prepared MEAD and DEAD samples were preliminary tested as a potential additive in diesel fuel. The research focused on measuring three key properties: i.e., foaming, lubricity, and cetane number. The results suggest that MEAD is a suitable additive for diesel fuel.

Abstract Wheat varieties (IS Danubius and MS Luneta) bred in Slovakia were assessed for their bakery potential. It was found that flour produced from IS Danubius was characterised by significantly higher level of wet and dry gluten content (30.91 and 20.53 %, respectively) and exhibited higher gluten swelling capacity (29.3 %) in comparison to commercial wheat flour that is usually available in Slovak markets. Solvent retention capacity (solvation in specific solvents) of the tested flours was also determined. The measurements showed that these parameters significantly differ from those determined for commercially available flour, whereas the flour produced from IS Danubius wheat variety had the highest lactic acid retention capacity (124.15 %). Correlation analysis indicated strong positive correlations between solvent retention capacity values and gluten characteristics. Furthermore, it was found that baked rolls prepared from IS Danubius flour showed significantly higher loaf volume compared to commercial wheat flour. This study proves lactic acid retention capacity and sucrose retention capacity as parameters enabling the prediction of gluten network quality in dough and of qualitative parameters of baked goods. From the sensory evaluation resulted that the highest score for overall acceptance was observed in IS Danubius baked rolls, which significantly differs from both MS Luneta and commercial wheat flour.

Abstract Adsorption of copper atom on benzene surface has been studied at the ab initio MP2 and CCSD(T) theory levels. CCSD(T)/CBS binding energies of the copper atom adsorbed on hollow, top, and bridge positions are 16.77, 19.27 and 21.08 kJ/mol, respectively. Adsorption at the bridge position represents the most stable structure of the Cu-benzene complex with charge transfer from benzene to the copper atom playing a key role.