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Food and Natural Products
Doctoral Programme,
Faculty of Food and Biochemical Technology
--- Careers--- Programme Details
Ph.D. topics for study year 2025/26Analysis of per- and polyfluoroalkyl substances in the human environment
AnnotationThis dissertation will focus on the development and optimization of analytical methods for determining a wide spectrum of per- and polyfluoroalkyl compounds (PFAS) in the environment, including food and drinking water, which represent the main dietary source of human exposure. The work will focus on expanding existing methods to include new substances from the PFAS group, and potentially implementing new procedures in PFAS analysis, such as determining total oxidizable precursors. For food, attention will be focused on commodities whose monitoring is required by current European Commission recommendations (EU 2022/1431). Liquid chromatography coupled with (high-resolution) mass spectrometry will be used for substance detection. The new procedures will then be applied to evaluate environmental burden and assess dietary exposure of the Czech population to these substances. The work will provide new data necessary for assessing exposure risks of different population groups to these substances and will also provide basis for implementing new European legislation in the following years. Authenticity and safety of spices, herbs and herbal products
AnnotationThis thesis should focus on the use of untargeted metabolomic analysis using advanced chromatographic methods coupled with mass spectrometric detection for the development of an analytical strategy for verifying the authenticity and detecting adulteration of various types of spices, herbs and herbal products. The aim of the work is also to simplify the procedures and convert the untargeted analytical procedure to the targeted analysis of several characteristic substances and the transferability of the method to common routine control practice. In this context, in subsequent experiments, emphasis will be placed on the assessment of the chemical safety of the analyzed products, especially in terms of the content of pesticide residues with the possible addition of the analysis of the content of other contaminants, such as mycotoxins or plant alkaloids. Within the broader framework of this work, it is possible to use other analytical techniques, such as infrared spectroscopy, or targeted analysis of already known markers of quality and authenticity of certain commodities, or other foreign substances with a negative effect on human health. Bioactive secondary metabolites in plant matrices / crops: their characterization and study of changes during processing
AnnotationThe doctoral thesis will focus on the comprehensive characterization of bioactive secondary metabolites (including toxic ones) in selected natural raw materials/crops; the dynamics of their changes under different processing conditions will also be studied. "Chemical fingerprints" of secondary metabolites will be obtained using ultra-performance liquid chromatography coupled with tandem high-resolution mass spectrometry (UHPLC-HRMS/MS). The interpretation of the results will be based on advanced statistical methods. A critical evaluation of various types of bioactivities of experimental matrices (antioxidant, antimicrobial, cytotoxic, etc.) will be carried out on the basis of screening tests, and correlations with the chemical composition of the samples will be sought. Biologically active compounds and their changes during cultivation, processing and storage
AnnotationThis thesis will focus on the development and optimisation of analytical methods for the study of biologically active compounds in different types of plant material, feed and food supplements. In particular, liquid chromatography coupled with conventional detectors and mass spectrometric detection will be used to determine the compounds of interest. The content of biologically active compounds depends on the species and variety of the plant and the method of cultivation. Their levels are significantly influenced by the storage of the raw material and its processing. Among the biologically active substances monitored with positive effects on human health are mainly important antioxidants such as carotenoids, vitamin C, tocopherols, phenolic substances and many other products of the secondary metabolism of plants. The work will provide data on the levels of biologically active compounds in organic and conventional crops and varietal diversity. The work will also aim to monitor the effect of storage and processing on the levels of bioactive compounds in raw materials, feed, food and dietary supplements and to assess their stability. Biotransformation of mycotoxins and their glycosides in the gastrointestinal tract, risk assessment
AnnotationMycotoxin glycosides represent a diverse group of substances found in cereal foods, and as the latest studies show, they are represented in relatively significant quantities. In terms of their structure, they differ mainly in the position of the sugar component binding to the aglycone (mycotoxin), the type of glycosidic bond between the aglycone and the carbohydrate part of the molecule, and in the form of the conjugated carbohydrate as such. Most mycotoxin glycosides are of limited resorbability in the small intestine, while in the large intestine, numerous biotransformation reactions occur through the intestinal microbiota, affecting their bioavailability. The subject of the planned research will be a detailed study of the dependence of the profile of mycotoxin biotransformation products on the species spectrum of the intestinal microbiota, both in healthy individuals and in patients in remission of Crohn's disease, who represent a particularly sensitive population group in terms of the composition and "safety" of the diet. The topic of the dissertation is part of interdisciplinary research planned within the framework of a project funded by the Czech Academy of Sciences. Cooperation with the Motol University Hospital is planned. Chemical safety assessment of edible insects
AnnotationThis dissertation focuses on the assessment of risks associated with the transfer of contaminants from the environment and feed to edible insects. The main objective is to analyse various chemicals, including environmental pollutants, pesticide residues and others, using modern analytical methods, particularly gas and liquid chromatography coupled with mass spectrometry. The transfer of these chemicals from contaminated feed or the environment to insects and their possible accumulation or metabolisation will be investigated. The findings of this research will make a substantial contribution to the evaluation of health hazards associated with the ingestion of edible insects and will support the development of safe and sustainable production systems. Evaluation of the spectrum of bioactive substances of aromatic and medicinal plants depending on environmental conditions
AnnotationAromatic and medicinal plants exhibit a wide range of biological activities, including antioxidant, anti-inflammatory and antimicrobial effects. Due to these properties, they are often of interest in the fields of pharmacology, food and cosmetics. The most important bioactive compounds include polyphenols, phenolic acids, flavonoids, terpenoids, coumarins and essential oils. The composition and quantity of these substances, which have a major influence on the biological effects of plants, depend on the environmental conditions. Factors such as soil composition, weed infestation or the presence of diseases and pests can significantly influence the spectrum and content of bioactive compounds. The dissertation will focus on investigating the influence of these external conditions on the chemical composition and biological activity of medicinal plants, and at the same time propose methods and procedures for the ecological revitalisation of these plants, minimising the use of classical chemical treatment. Comprehensive characterization of natural and synthetic aromas based on progressive analytival strategies
AnnotationThe doctoral thesis will focus on a highly topical issue: the comprehensive characterization of mixtures of volatile substances in various types of natural matrices such as medicinal or aromatic herbs, spices or essential oils prepared from them. Selected synthetic aromas will also be studied. For the analysis of volatile compounds, a unique robotic instrumental platform combining sample preparation, or rather isolation of volatile compounds and their concentration with subsequent gas chromatographic separation coupled with a high-resolution mass spectrometer with an orbitrap analyzer, will be used. The obtained results will be used in cooperation with various companies in the development of new, sensory attractive products; control of synthetic aromas will be carried out within the assessment of their safety. “Masked” mycotoxins in the barley-malt-beer chain
AnnotationThe presence of mycotoxins in raw materials for malt production, and therefore in malt and beer, is a long-discussed, but still unresolved, food safety problem. The dissertation will address the issue of occurrence, detection and quantification of various forms of glycosylated mycotoxins in barley, as the majority starting raw material for malt production. The latest and as yet unpublished data regarding the content of non-extractable mycotoxins bound to polysaccharides of malting cereals indicate an enormous amount of these substances, which cannot be directly detected by conventional analytical approaches, but from the perspective of the upcoming malting and brewing industry they represent a problem, since enzymatic hydrolytic reactions occurring during these technologies enable effective hydrolysis and the formation of lower glycosides or aglycones themselves (mycotoxins), which pose a health risk to consumers. The dissertation will address not only the chemical nature of mycotoxins bound to polysaccharides using a wide range of analytical techniques, including mass spectrometry, but will also address the possibilities of predicting mycotoxins in beer based on the composition of barley and malt, especially with regard to (poly)saccharide components and total mycotoxin content. Process contaminants in selected foods: mechanisms of origination and mitigation options
AnnotationThe doctoral thesis will focus on a comprehensive assessment of the formation of process contaminants and other undesirable compounds under various conditions of heat treatment of food raw materials. Attention will be paid primarily to acrylamide, esters of 3-monochloropropanediol and/or glycidol with fatty acids, furan and its derivatives, as well as other nutritionally undesirable compounds. Mitigation measures will be studied, consisting not only in the selection of raw materials / ingredients with a low content of precursors of process contaminants, but also to the use of ´mild´ technologies such as vacuum frying. The assessment of the chemical safety of the obtained products will be supplemented by an evaluation of their sensory quality. Development of rapid screening methods to assess food safety, quality and bioactivity
AnnotationThis doctoral thesis will focus on the develompent of analytical methods that can be used to rapidly assess food safety, quality and/or bioactivity. Different approaches will be investigated including i) bioanalytical methods, e.g., based on enzyme activity/inhibition, ii) spectroscopy, e.g., vibrational spectroscopy, and iii) method miniaturisation for testing at the point-of-need (outside the lab, at the field, at the food industry setting etc.). Practical challenges such as sample preparation and method quality assurance will be also addressed while cases studies will be investigated focusing on topical issues within the food scheme. Finally, the newly developed methods will be benchmarked towards chromatographic analysis, the golden standard in the field, to highlight advantages/drawbacks. |
Updated: 20.1.2022 16:26, Author: Jan Kříž