| Start Date: | 3 октомври 2026 |
| End Date: | |
| Project Leader: | Yordanka Karakirova |
| Budget: | 425 000,00 лв. |
Abstract
Irradiation with ionizing radiation has wide applications in various fields of human activity. Over the past three decades, gamma irradiation has been used as a fast, reliable, and cost-effective method to improve the quality and extend the shelf life of food products by preventing the development of pathogenic microorganisms. Despite its advantages, this approach leads to the formation of free radicals and may affect the content of polyphenolic compounds, which are the main carriers of antioxidant activity. On the other hand, working with ionizing radiation necessitates strict monitoring of radioactive processes and dosimetric control through the use of a reliable dosimetry system. One of the most suitable and effective methods that has been successfully applied for both identifying radiation-induced free radicals in materials and studying the effect of gamma irradiation on the radical scavenging ability of substances is Electron Paramagnetic Resonance (EPR) spectroscopy. Moreover, the method finds wide application in investigating the dosimetric characteristics of substances, with a specific branch of EPR spectroscopy known as EPR dosimetry. Although EPR spectroscopy is a suitable method for research in chemistry, physics, biology, medicine, and other areas of science, it is still not among the most widely used. The reason for not utilizing its advantages such as selectivity (only for detecting paramagnetic particles), high sensitivity (10−11 to 10−12 M), and the nondestructive nature of measurements is the expensive and bulky equipment, as well as a lack of sufficient experts in this field. In recent years, portable EPR spectrometers have been developed, significantly facilitating its broader use. Other instrumental techniques that will be employed in the present research work include UV-Vis spectrophotometry, High-Performance Liquid Chromatography (HPLC), and IR spectroscopy to compare results for a more comprehensive study. In this project proposal, research will be conducted on methodological issues and tasks in the following main directions: • Determining the type and stability of free radicals generated in food products and herbs as a result of radiation treatment; • Developing an approach for qualitative and quantitative assessment of irradiated foods using the added dose method; • Studying the influence of gamma irradiation on the antioxidant properties of natural substances; • Developing solid-state/EPR dosimeters for determining the absorbed dose of radiation based on saccharides and amino acids. The following objects will be studied: • Foods (including marine) and natural products with both natural and irradiation-induced EPR activity; • Plant-derived products (chestnut, sea buckthorn, self- heal etc.) possessing antioxidant properties; • Natural and synthetic substances (saccharides and amino acids) for the development of solid-state/EPR dosimeters. The planned research will contribute to a more comprehensive understanding of the radiation effects on food and natural products and will offer new strategies for monitoring and controlling radiation exposure.Назад...
