Ulyana A. Bliznyuk

The effect of low-energy ionizing radiation in the dose range of 5–30 Gy on the biological performance of rapeseed (Brassica napus) seeds was investigated. Presowing irradiation led to an improvement in both germination rate and crop productivity. X-ray irradiation at doses of 15, 20, and 25 Gy increased rapeseed yield by 298, 130, and 202%, respectively, in comparison with a reference group. Irradiation with accelerated electrons at doses of 30 and 25 Gy increased the yield by 42 and 126%, respectively.

Electron beam irradiation, extensively used for suppressing a wide range of pathogens contaminating food products, pharmaceuticals and biological raw materials, inevitably damages the surrounding proteins, stripping the product of its essential nutritional and functional properties. This issue can be addressed by adjusting the electron beam irradiation dose, bearing in mind the concentration of proteins in the product since it can affect the rate of radiation-induced modifications in proteins. The study investigates the impact of 7.5 MeV electron-beam irradiation on modifications in bovine serum albumin (BSA) molecules in 0.9% NaCl solution in the concentration range of 0.5–70 mg/mL, encompassing a wide range of protein concentrations in food products, pharmaceuticals and biological raw materials. Conformational changes and aggregation of BSA were evaluated using UV–Vis spectrophotometry at λ = 350 nm. Peptide bond rupture in protein native structures was assessed by performing HPLC-MS/MS analysis after trypsin hydrolysis using three selected peptides located in different domains of the BSA amino acid sequence. It was found that the rate of radiation-induced modifications increased with an increase in the irradiation dose but decreased markedly as BSA concentration increased. While at the BSA concentration of 0.5 mg/mL over 87% of BSA molecules underwent peptide bond rupture under irradiation with a dose of 5 kGy, a two-fold increase in the BSA concentration and irradiation dose enabled bond rupture in only 20% of BSA molecules. Our experimental approach resulting in the development of the dose and concentration model allows us to quantify the degree of radiation-induced protein modifications depending on the irradiation dose and protein concentration in food products, pharmaceuticals and biological raw materials.

The interaction between proteins and salts in aqueous solutions represents a compelling scientific problem in both biophysical and medical research. One manifestation of the interaction in the bovine serum albumin (BSA)–NaCl–H₂O system is the formation of ordered patterns upon droplet drying. In our experiments, the topographic features of the deposited particles as well as their elemental composition were studied using optical microscopy and scanning electron microscopy (SEM). In this work, we experimentally investigated the stepwise change in the characteristic structures of the precipitate with an increase in the BSA concentration from 0.005 to 35 mg/mL. The formation of discrete BSA–NaCl ring deposits near the droplet edge and around crystallization centers in the interior at BSA concentrations of 0.05–1 mg/mL proved particularly interesting. We demonstrated the sequence of ring structure formation: the process primarily begins with the formation of BSA aggregates arranged in sectors around the circumference, which in turn serve as nucleation sites for NaCl crystallization. We propose a qualitative conceptual–phenomenological interpretation of the observed experimental effects. Concentration-dependent patterns in the emergence and development of other patterns (such as spikes, fractal structures, and chrysanthemum-like formations) were established. These results expand our understanding of protein behavior in aqueous-salt solutions. This can be used in medical diagnostics as biomarkers. The characteristic patterns presented in the work can serve as a useful experimental basis for further studies of the impact of physicochemical factors on proteins and other biopolymers.

Food irradiation is increasingly used to extend shelf life and control pests and diseases. Monitoring post-treatment doses typically relies on expensive, laborious instruments and may miss low doses. We previously proposed a chemical fingerprinting method that estimates dose based on indicator reaction rates, but this approach was tested only on freshly irradiated samples. In this study, we investigated the feasibility of determining the order of magnitude of dose in irradiated raw potato tubers after several days of storage. A completely randomized experimental design was used. Water extracts of potatoes were assayed in oxidation–reduction and aggregation reactions in 96-well plates; reaction rates were tracked by absorbance and fluorescence and analyzed chemometrically. We could distinguish dose orders of magnitude (0, 100, 1000 Gy) after 0, 2, and 6 days of storage at 4 °C. The accuracy of dose recognition on day 6 was at least 97% by using SoftMax regression (SR) or linear discriminant analysis (LDA); irradiated and non-irradiated samples were confidently distinguished using partial least square–discriminant analysis (PLS-DA). The reaction-based method of dose assessment is simple, rapid, and does not require sophisticated equipment.

Food irradiation is gaining popularity worldwide as a method for extending shelf life and controlling pests and diseases. Post-treatment irradiation doses are usually monitored using instrumental methods, which may be expensive, labor-intensive, time-consuming, and not allow for low-dose detection. We previously proposed a chemical fingerprinting strategy for estimating irradiation doses based on measuring the rate of an indicator reaction. However, the feasibility of dose assessment was demonstrated only for freshly irradiated samples. In this study, we investigated the feasibility of determining the order of magnitude of dose in irradiated raw potato tubers after several days of storage. The samples were extracted with water, and the extracts were introduced into oxidation-reduction and aggregation reactions carried out in a 96-well plate. The reaction rates were monitored by measuring absorbance and fluorescence of the reaction products, followed by chemo-metric processing. The feasibility to estimate doses to an order of magnitude (0, 100, 1000 Gy) was shown for storage time of 0, 2, and 6 days at 4°C. The accuracy of dose recognition on day 6 was at least 97% by using SoftMax regression (SR) or linear discriminant analysis (LDA). Irradiated and non-irradiated samples can be confidently distinguished using partial least square–discriminant analysis (PLS-DA). The reaction-based method of dose assessment is simple, rapid, and does not require sophisticated equipment.

This study investigates the impact of 1 MeV electron beam and 80 keV X-ray irradiation on the decomposition rate and radiation–chemical yield of 1-hexanol in aqueous saline solution to develop a comprehensive approach to determining reliable volatile organic compound markers for food irradiation. A 50 mg/L 1-hexanol solution was irradiated with the doses ranging from 100 to 8000 Gy at various dose rates ranging from 0.2 to 10 Gy/s to assess the impact of irradiation parameters on the decomposition rate and radiation–chemical yield of volatile compounds typically found in food. GC–MS analysis revealed a non-linear decrease in 1-hexanol concentration with increasing dose, accompanied by the formation of aldehydes, ketones, and secondary alcohols. Among these products, hexanal was detected at the lowest applied dose and exhibited dose-dependent behavior that correlated strongly with 1-hexanol degradation. Density functional theory calculations identified the most probable pathways for the formation of hexanol decomposition products, involving direct ionization, radical reactions, and oxidation. A mathematical model proposed in the study describes dose-dependent transformations of 1-hexanol into hexanal, enabling quantitative estimation of the degradation extent of hexanol. The findings suggest that hexanal can serve as a quantitative marker for hexanol degradation, supporting the development of rapid “dose range” determination methods for food irradiation that ensure microbial safety while minimizing undesirable oxidation of proteins, fats, and carbohydrates.

Background: Recently, extensive use of antibiotics has increased the amount of antibiotic residues in the natural water environment. Methods: This study presents an experimental investigation into the degradation of penicillins, tetracyclines, streptomycin and chloramphenicol in aqueous solutions when exposed to 1 MeV accelerated electrons with doses of 0.1, 1, 3 and 7 kGy using HPLC-HRMS analysis. Results: It was found that electron beam irradiation with a dose of 7 kGy ensures 98–99% removal of antibiotics, with the initial concentrations ranging from 15 mg/L to 30 mg/L depending on the class of antibiotic. The mathematical model proposed in the study, which estimates the dose dependencies of the relative concentrations of antibiotics and their degradation products in aqueous solutions, reveals different decomposition rates of antibiotics of different classes due to the different radiosensitivities of antibiotics. It has been found that tetracycline has a considerably higher radiation–chemical yield compared to the other antibiotics when exposed to accelerated electrons. Conclusions: Using density functional theory in combination with the mathematical model, we have developed a novel approach to establishing a quantitative irradiation marker of antibiotic degradation as a result of irradiation, which involves finding the degradation product whose formation requires a minimum number of ionization events. Using such an approach, it is possible to establish the extent of antibiotic degradation in water after irradiation with different doses and find the optimal irradiation doses for industrial water treatment.

Catalase serves as a crucial component of the antioxidant defense system by catalyzing the decomposition of hydrogen peroxide into water and molecular oxygen. This study investigated the effects of 1 MeV accelerated electron irradiation on catalase activity in model solutions at doses of 100 Gy and 1000 Gy. Enzyme activity was assessed using two complementary methods: spectrophotometric analysis and the oxygen bubble method. The experimental results demonstrated dose-dependent inhibition of catalase activity, indicating that substantial radiation-induced structural modifications may occur in the enzyme molecule as a result of irradiation. To understand the relationship between the irradiation dose and the catalase inhibition, calibration curves plotting the dependencies of hydrogen peroxide decomposition rate and the delayed appearance of oxygen bubbles after adding hydrogen peroxide to catalase saline solution on the catalase concentration showed a 1.5-fold reduction in catalase activity at 100 Gy and a 40-fold decrease at 1000 Gy. Based on these findings, we propose a novel biodosimetry approach utilizing the oxygen bubble formation delay time as an express assessment tool for detecting high radiation doses absorbed by biological objects, for example, food products. The results obtained in the study have important implications for evaluating radiation effects on biological systems, in particular catalase-containing food products, offering potential applications in radiation safety monitoring and food quality control.