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Characterization of proteins, soluble gums and phenolic compounds isolated from flaxseed (Linum usitatissimum L.)
JAROŠOVÁ, Markéta
Flax (Linum usitatissimum L.) is one of the oldest domesticated crops. Its cultivation for fibre, oil or medicinal purposes was already widespread in ancient times. Nowadays, the growing of flax for the production of high-quality flaxseed oil prevails compared to fibres. However, using flaxseed as a functional food in the food industry and dietary applications has become more popular recently. Flaxseed contains bioactive components, including polyunsaturated fatty acids representing the major proportion of flaxseed oil, as well as functional proteins and peptides, lignans and dietary fibre in the forms of soluble mucilaginous polysaccharides and insoluble lignocellulose. This dissertation presents the results focused on characterisation of three significant constituents of flaxseed - proteins, polysaccharides and lignans. These groups of compounds exhibit interesting functional properties and biological activities that may be useful in a wide range of food or medical applications. This work highlights the importance and potential use of flaxseed oil cake, which is an important source of these components. In addition to the results, this thesis also provides a comprehensive literature review of previous and current research on flaxseed proteins, mucilages and lignans. The results of this work can be primarily applied to breeding new oilseed flax cultivars or in the food and processing industries. However, due to the important nutritional aspects and biological activities of the mentioned components, the obtained findings can also be used in dietary applications and medicine. In general, this work aims to expands the spectrum of knowledge on the subject and to open up the scope for further research. Two review articles represent the first part of the results. The first publication focused on the hydrocolloids of flaxseed in the form of flaxseed mucilage representing 4-15% of the flaxseed content and protein representing 20% of its weight. In this manuscript, the structure, extraction methods, functional and biological properties and possible applications of both types of hydrocolloids for the fortification of various foods or other food applications are described in detail. This manuscript is followed by a short review article summarising current trends in food and dietary applications of flaxseed mucilage. The first publication describes more likely the traditional use of flaxseed mucilage for food fortification to enhance the technological, nutritional or sensory quality of foods or to provide health benefits. The second review paper focuses exclusively on the potential use of flaxseed mucilage in recent and innovative food industry and nutrition areas. In modern applications, flaxseed mucilage can be applied, for instance for preparing films, for food protection, as a structural component in oleogels, cryogels or aerogels, and it may modify the functional properties of proteins within composites. From the point of nutrition, flaxseed mucilage can serve as an encapsulating agent for probiotics or biologically active compounds. Flaxseed mucilage has the characteristics of a prebiotic and may increase the proportion of beneficial probiotic microorganisms. As a result, both review articles highlight the significant potential of flaxseed proteins and flaxseed mucilage for various recent and future applications. The second part of this thesis represents a first-authorship original manuscript focused on researching the influence of variety and growing conditions on yield parameters, chemical composition, lignan content and antioxidant potential of flaxseeds.
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Analysis of functional properties of protein isolates
Vojtasová, Tereza ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
Proteins are an important part of the human diet, and a lack of them can lead to many health problems. Therefore, they are often added to enrich foods. For food applications, it is desirable to know the functional properties of the proteins used, as they can significantly affect the resulting quality of the final product. This bachelor thesis was focused on the determination of functional properties of some commercially available protein powders: pea, beef, hemp, rice, egg, soy, whey, and laboratory-prepared wheat bran protein powder, and their possible application in food industry. The theoretical part of the thesis described proteins, their functional properties, production, quality assessment, then plant and animal proteins and methods of characterization of protein isolates and concentrates. In the experimental part, individual determinations of functional properties were performed and their applications in food industry were discussed. The solubility of tested protein powders was variable, with the highest solubility observed in powders of animal origin. The lowest solubility was found at pH 3–5, where the isoelectric point of most proteins was located. Soy protein isolate showed the best water-holding capacity of 10.65 gH2O/g, foaming capacity of 109.6% and emulsion properties. It was followed by pea protein with a WHC of 5.32 gH2O/g. Wheat bran concentrate had the best oil holding capacity of 2.18 goil/g. Foaming properties varied considerably but showed a positive correlation with water-holding capacity. The emulsion activity was very similar for most of the protein powders, except for beef, hemp and rice protein which exhibited no good functional properties. Only the beef hydrolyzed collagen was fully soluble. The emulsion layer increased slightly after heat treatment for the proteins, which already formed quite stable emulsions, except for wheat bran powder. Hemp and bran protein powders were the most distinctive in color, while egg and beef protein powders were the lightest. Soy and pea protein isolates showed foaming and emulsion properties similar to egg white proteins, indicating their potential use as partial or total replacements for egg white proteins in food products. In conclusion, selecting protein isolates with suitable functional and sensory properties for a specific food application is crucial for successful consumer acceptance of the protein-enriched product.
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The quality of eggs - general, functional and nutritional properties
PECH, Miloslav
This bachelor's thesis, processed in the form of a literary review, focuses on a comprehensive view of hen's eggs, analyzing their general, functional, and nutritional properties. After the introduction, a literary review follows, mapping the biological origin and domestication of the chicken, and then summarizing the current state of chicken farming. The thesis then delves into the formation and development of eggs, examining the structure and chemical composition of the yolk and albumen, including their proteins, lipids, carbohydrates, pigments, vitamins, and minerals. The physicochemical properties of eggs are also analyzed, including a total of seven properties such as specific gravity, freezing point, or refractive index. A detailed examination of the functional properties of eggs follows, which represent a key element in understanding their wide use in the food and culinary industries. The thesis focuses on analyzing the mechanisms through which hen's eggs can form gels, foams, and emulsions, which are properties that play an important role in various food processes and recipes. These properties are essential for the production of various foods, such as gelatin desserts, leavened doughs in baking, sauces, and mayonnaises. Eggs are also recognized as functional food because they are a rich source of nutrients, including vitamins, minerals, and biologically active substances that can contribute to overall health. These substances can, for example, help reduce the risk of heart disease and improve eye health. In the next section, the thesis focuses on the nutritional properties of eggs, examining microbial contamination, egg allergies, and biologically active substances such as choline, immunoglobulin Y (IgY), and lutein and their impact on human health. An overview of this section provides a deeper understanding of hen's eggs and their influence on human nutrition and health.
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Long term dynamic of vegetation succession on post-mining sites.
Skalníková, Andrea ; Mudrák, Ondřej (advisor) ; Janíková, Eva (referee)
Spontaneous succession of vegetation can be one of the restoration approaches of disturbed sites after coal mining. It is therefore important to know the course of successional changes and whether it can be replicated. The spontaneous succession of vegetation on disturbed sites is usually based on monitoring of multiple sites of a different stage of succession. By their comparison the course of the succession over time is inferred. This approach of the study is called chronosequence (space-for-time substitution). Another option is to repeat monitoring of permanent plots, but it requires a long period of time to observe successional changes. Rarely are these approaches combined. In this thesis, I analyse the main trends in the succession of plant communities and their plants functional traits on five localities of various age during the 15 years. I have examined whether the localities follow similar successional trends. Data (plant coverage) were collected by annual resampling of 50 (ten per locality) permanent plots of 5 m x 5 m since 2007. By performing a multivariate CCA analysis, we analysed the species composition of the plant community, and by performing an RDA analysis, we analysed the changes in weighted averages of plant functional traits. In both cases, the localities and their...
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The relationships among functional traits of tardigrades (Tardigrada), their diet, and environmental conditions
TŮMOVÁ, Michala
In this thesis, I explore several ways how to use functional traits to study the tardigrade role in the soil food web. The goal of the thesis was to show that it is possible to study tardigrade ecology even without species identification. Trophic classification of tardigrades, as well as morphometric traits of each individual, were used as functional traits. First, I confirmed the existence of different trophic groups, testing the whole spectrum of potential diet in three tardigrade species from different trophic groups. I showed that tardigrades differed not only in the scope of ingested items but also in survival and fecundity under different types of diet. Secondly, I compared trophic group composition with species composition in natural tardigrade communities. The results showed that species, as well as trophic group composition, responded to the same environmental drivers. Trophic group composition enabled easier interpretation of the tardigrade role in the soil food web, while species composition illustrated also species-specific preferences that were not connected to their feeding habits such as preferences for different levels of soil moisture. Finally, I have used morphometric traits measured in each individual separately which allowed me for evaluation of inter-specific as well as intra-specific variation. As a result, buccal tube length was selected as a predictor of tardigrade feeding preferences among nematode, rotifer, and tardigrade prey. In summary, the thesis documented that functional traits provide a tool for the prediction of tardigrade feeding behaviour and detection of changes in the role of tardigrades along environmental gradients without the need of species identification.
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The efficiency of pollen transfer by selected functional groups of pollinators and the ability of plants to influence it
Freudenfeld, Martin ; Janovský, Zdeněk (advisor) ; Klečka, Jan (referee)
Pollinator functional groups differ in their pollen carryover effectiveness and in the importance for particular species of plants, due to specific functional traits of pollinator functional groups. Plant species differ in their specific functional traits too. I determined pollen loads of pollinators by swabbing their bodies with a jelly to compare pollen carryover effectiveness of pollinator functional groups. This helped me to decide which pollinator functional groups are the most and the least effective in pollen carryover. I considered an influence of the last visited flower to make the comparison of pollen loads more accurate. I also calculated proportions of conspecific and heterospecific pollen grains carried on bodies of pollinators to estimate their carryover effectiveness. Likewise, I compared composition of pollen morphotypes carried on pollinator's bodies to find out differences among pollinator functional groups. My analysis shows that pollen carryover effectiveness of particular pollinator functional groups differ. Apis mellifera and solitary bees have the biggest pollen loads, on the other hand, butterfies and small dipterans have the smallest pollen loads. The last visited flower influences an amount of pollen grains carried on bodies of pollinators. Relative pollen loads of some...
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Pollinator pollen carryover effectiveness and plants' ability to enhance it
Freudenfeld, Martin ; Janovský, Zdeněk (advisor) ; Mikát, Michael (referee)
Pollinators carry over pollen from one flower to another. They facilitate plant reproduction. Pollinator functional groups differ in their effectiveness of pollen carryover. Quantity of pollen grains on their body and deposition on stigma are very important. Pollinator carryover capacity depends on its functional traits. Body size, hairiness, visitation behaviour, foraging preferences, flower constancy and abundance of pollinators are significant. Plants can enhance effectiveness of their pollination by adaptations to specific pollinator functional groups. They improve positioning of pollen on pollinators by specific changes to floral morphology, quantity and size of pollen grains. They can also enhance the effectiveness through aggregation of pollen grains into groups or into pollinia or by optimisation of pollen release in time.
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Technologické vlastnosti křepelčích vajec
Dostálová, Marie
Technological properties, in other words functional properties, of quail eggs influence the preparation and production of food. The basic functional properties of egg albumen include gel formation, foam formation and suppression of crystallization. Gel formation is important in the production of boiled quail eggs. Foam formation is necessary in the production of confectionery and bakery products. Suppression of crystallization is used especially for confectionery. The functional properties of egg yolk can include the emulsion formation and antioxidant action of the phospholipids of yolk. Emulsion formation is important in mayonnaise production. For certain technological properties, there are defined criteria, which describes applicability and quality of eggs. Foam ex-pansion index, foam stability index, foam density and toughness are obtained during the foam formation of quail fresh or dried albumen. Emulsion stability index and emulsion activity index are obtained during formation of emulsion from quail fresh or dried yolk. Functional properties are influence affected for example by solubility of protein, water-holding and oil-holding capacity.
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Evaluation of functional properties of selected vegetable flours
VÍTKOVÁ, Věra
This bachelor thesis deals with basic structure, nutritional properties, production and use of flours. There are information about cereals and legumes, which are used for productions of flours. This thesis talks about food intolerances, which can be a reason why change basic flours of wheat, barley, oat and rye to another. Practical part is about 14 flours, which were tested on dry matter, humidity, nitrogen substances content, proteins, protein electrophoretic profiles (patterns), solubility, water and fat holding capacity, formation of gels and changes of colours during a boiling. The results of this research are information about nutrition and functional properties of tested flours.
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