Boshevska, Marija (2022) КОМПАРАТИВНА АНАЛИЗА НА ПРОМЕНИТЕ ВО КВАЛИТАТИВНИОТ СОСТАВ КАЈ ХРАНА ТРЕТИРАНА СО ЈОНИЗИРАЧКО ЗРАЧЕЊЕ. Doctoral thesis, University "St.Kliment Ohridski" - Bitola.
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Abstract
Food irradiation is a method that has always caused numerous dilemmas, open questions and unclear views among consumers. In order to investigate the effects of this form of energy on food, in this doctoral thesis, an analysis of changes in the qualitative composition of food treated with ionizing radiation was made. Comparative physicochemical and microbiological analyzes of wheat (Triticum aestivum L.) has been conducted through subjecting samples to ionizing radiation treatment, with five different doses: 0.2 kGy, 0.5 kGy 1 kGy, 5 kGy and 10 kGy. Wheat was obtained from the production facilities of ZK Pelagonija, immediately after the harvest in 2020. Results are conceptualized in 6 chapters.
The first chapter analyzes the effects of ionizing radiation on the qualitative composition of the wheat. The results of this section showed that all treated samples correspond to the requirements of the Rulebook on quality of cereals, mills and bakery products. Almost equal values of all examined parameters were determined, as follows: carbohydrates (64.34 % – 65.19 %), total proteins (10.04 % –10.52 %), fats (1.31 % –1.39 %), dietary fiber (12.3 % – 12.4 %), moisture (9.61 % – 9.78 %), ash (1.39 % – 1.47 %) and sand (0.048 % – 0.05 %).
The second chapter concerns the detection of food treated with ionizing radiation, conducted on the examined samples. Confirmation that the samples were treated wheat with ionizing radiation, was conducted with the methods of photostimulated luminescence and thermoluminescence. The results showed that both methods give unreliable results if the treatment is performed at low doses (0.2 kGy and 0.5 kGy) and reliable results if the treatment is performed at doses of 1 kGy, 5 kGy and 10 kGy.
The third chapter examines the longevity of the effects of ionizing radiation on treated specimens. The results in this section showed that there were no significant differences in the qualitative composition of wheat associated with the aging of the specimens, except for the values of carbohydrates (which decrease with storage) and the percentage of moisture (which increases in parallel with the length of storage).
The fourth chapter refers to the microbiological profile of wheat and the effects of ionizing radiation on the number of microorganisms present. The results showed presence of Bacillus cereus, Enterobacteriaceae species and yeasts and molds. Salmonella, Pseudomonas aeruginosa, Escherichia coli and Clostridium perfringens, were not detected in the examined
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samples. It has been found that the number of microorganisms decreases in parallel with increasing the dose, with no viable microorganisms at a dose of 10 kGy.
In the fifth chapter, the longevity of the effects of ionizing radiation was analyzed. It was concluded that in all examined samples, after a period of nine months after ionizing irradiation treatment, there is a noticeable reduction in the number of microorganisms. In fact at a dose of 5 kGy only yeasts and molds were detected, while at a dose of 10 kGy no microbial growth was observed. This confirms the prolonged effect of ionizing radiation on the microbiological safety of food.
In the last (sixth) chapter, the effect of ionizing radiation on aflatoxin concentrations was investigated. Their mean values were 3.85 ppb, which are within the allowed concentrations for aflatoxins in all cereals and products derived from cereals in accordance with the legislation. Their significant reduction was found in parallel with dose increasing. A reduction of their concentrations of 40 % has been determined at a dose of 5 kGy and by 48 % at a dose of 10 kGy. Based on all the results obtained in this doctoral thesis, it can be confirmed that the treatment of food with ionizing radiation is an efficient and safe procedure that maintains the quality of food and extends its shelf life.
These results will contribute to the public education about the safety and benefits of treating food with ionizing radiation, thus overcoming the numerous dilemmas, misconceptions and open questions that exist in this area
| Item Type: | Thesis (Doctoral) |
|---|---|
| Subjects: | Scientific Fields (Frascati) > Engineering and Technology > Industrial biotechnology |
| Divisions: | Doctoral Dissertations |
| Depositing User: | M-r Bojan Mihajlovski |
| Date Deposited: | 29 Nov 2023 08:29 |
| Last Modified: | 29 Nov 2023 08:29 |
| URI: | https://eprints.uklo.edu.mk/id/eprint/9159 |
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