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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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Proteomic resolution of cereals
Nyškovská, Kristýna ; Kučková, Štěpánka (advisor) ; Kolář, Karel (referee)
This bachelor thesis deals with the proteomic differentiation of cereals (amaranth, sown barley, sown maize, qinoa, grain sorghum, sown oats, sown wheat, sown buckwheat, sown millet, sown rice, spelt, sown rye). Cereals are abundant in the human diet and are one of the main sources of protein and carbohydrates. The aim was to determine whether it is possible to distinguish between different types of cereals and to compare the difference between cereals and pseudocereals based on the protein composition of their grains using the mass spectrometric method MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization - Time of Flight. The theoretical part deals with the introduction of cereals, pseudocereals and their nutritional values, application and analytical method MALDI-TOF MS. The experimental part deals with the collection of different cereal species and their subsequent analysis. The samples were mechanically processed and digested using the enzyme trypsin. The cleaved peptides were measured by MALDI-TOF MS and the obtained spectra were subsequently processed using mMass and PostgreSQL (version 14.2). In this way, specific m/z values were determined that are characteristic of each cereal analyzed. From these values, a table was compiled that summarizes these characteristic values. Which allows the...
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Monitoring fiber and protein intake in obese clients of a nutrition counseling center
Kekrtová, Magdaléna ; Pejšová, Hana (advisor) ; Weidenthalerová, Edita (referee)
The obesity epidemic is still a very topical problem and requires a comprehensive therapy that includes nutritional counselling. In my practical experience, the topic of protein and fibre tends to be very common with obese clients and I often observe less than appropriate choices in terms of protein sources. Fibre is not given much importance and therefore its adequate intake is not optimal. Therefore, the theoretical part aimed to summarize the current knowledge about obesity, protein and fibre. However, nutrition in obesity is summarised in a comprehensive way, taking into account other nutrients, but also micronutrients or drinking, which may also be significantly related to obesity. The theoretical summary of obesity was summarized rather marginally. In terms of treatment approaches, diet therapy, physical activity or psychotherapy are more approached. The importance of the nutritional therapist is not neglected. The practical part was quite comprehensive. The aim of the study was to assess dietary habits (qualitatively and quantitatively, focusing mainly on protein and fibre), body composition before and after the nutritional intervention and thus to evaluate the effect of the therapy. It was also intended to provide information on the original dietary habits of obese individuals in terms of...
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Influence of beer protein on foam stability
Benda, David ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the influence of beer proteins, phenolic compounds, bitterness and selected metal ions on beer foam stability. The theoretical part describes beer foam from the physical aspect, beer foam stability and its measurement and the factors that positively or negatively influences the stability and quality of the beer foam. In the theoretical part are described selected proteins that influence beer foam. In theoretical part is described the origin and technological significance of proteins. The experimental part is dedicated to the measurement of beer foam stability with the NIBEM method, the analysis of total protein content, the analysis of total phenolic content, bitternes and element analysis of beer samples. Measured data indicated correlations between protein content, phenolic compounds content, bitterness and metal ions with the beer foam stability. The results show that proteins and phenolic compounds as isolated parameters don’t essentialy affect the beer foam stability. It was found out, that bitterness as isolated parameter influences the beer foam stability the most.
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Production and characterization of protein isolates from different kinds of bran
Vybíral, Lukáš ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with the use of various types of bran as a by-product in the milling of cereals. Mills create a huge amount of this material per year. The most common way of processing bran is mostly incineration and to a lesser extent it is used as feed for livestock. Depending on the type of cereal, bran contains 10-20% of protein, which disappears from the food chain due to combustion. Within the framework of sustainability and valorisation of waste, which has recently been largely discussed, great emphasis is placed on waste minimization whether in the field of its production or further processing. Due to the relatively high protein content, bran appears to be a suitable starting material to produce protein supplements. Proteins can be extracted from bran based on their different solubility at different pH. In the alkaline method, the proteins are first dissolved in an alkaline pH and then precipitated in an acidic medium. Lyophilization is followed by characterization of the extract in terms of yield, protein content, moisture, amino acid profile and digestibility. The highest yield was obtained with the oat bran isolate (13,5 ± 0,6 g of isolate per 100 g of bran). In terms of protein content, the best protein isolate was also obtained from oat bran (95,2 ± 0,4% protein in the isolate). Another determination was the analysis of the amino acid profile, in which a high content of arginine was found in all analyzed protein isolates from bran. Determination of digestibility showed very good digestibility of all produced protein extracts from bran.
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The assessment of basic chemical parameters of natural cheese
Školová, Dominika ; Babák, Libor (referee) ; Vítová, Eva (advisor)
The aim of this work was to determine basic chemical parameters of natural cheese, namely Camembert type (white mold cheese) and Emmentaler type (cheese with high-heat curd). Model samples of cheese were produced in a pilot plant using unpasteurized milk in"organic" quality. Based on the literature search following parameters suitable for simple and fast characterization of cheese composition were selected: dry matter (drying to constant weight), fat in dry matter (calculated), total nitrogen (resp. determination of protein content) by the Kjeldahl method and fats, resp. total lipids (extraction with solvent). The results were finally compared with samples of the corresponding cheese type purchased on the market.
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Determination of total protein, carbohydrates and polyphenols in beer
Dostálová, Blanka ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This master‘s thesis deals with the analysis of 65 different beers, with a focus on finding differences between Czech tap ales, lagers Czech, Czech special beers and foreign beers. Czech beers were compared by the results of analysis among beers bearing the indication "Czech beer" and the group without this indication. The total amount of proteins, polyphenols and carbohydrates was determined using UV-VIS spectrometry. The history of brewing, the nature and types of Czech beers and protected geographical indication "Czech beer" were described. Raw materials for beer production and brewing technology have been listed and described. In the last part of the research, components of beer and the principle of the UV-VIS spectrometry have been specified. Th determination of total protein was performed using Hartree-Lowry method, which is based on two-component reagent. The first component is the biuret agent, the second component is the Folin-Ciocalteau reagent for phenols. Determination of the polyphenols has been carried out by the Folin-Ciocalteau reagent and total carbohydrates were determined spectrophotometrically according to the Analytica EBC using anthron agent. The results were statistically processed and evaluated in the final part.
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The Study of Biopolymers Stability Using Light Scattering Techniques
Kratochvíl, Zdeněk ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
The stability of chosen biopolymers (or simple carbohydrates and amino acids) was in-vestigated using light scattering methods. Samples were prepared by dissolving the sub-stance in deionised water or in diluted acetic acid. Firstly, the effect of increasing concen-tration on zeta potential was observed and the optimal concentration for the next measure-ments was determined. Afterwards, the stability and the molecular weight of used sub-stances were studied during long-time storage in different time intervals. It was found out that chitosan, CMC, hyaluronate and sodium alginate were subjected to degradation whereas increase of the molecular weight and the zeta potential was observed in case of BSA. In the end, the samples were exposed to several different external effects, namely the influence of different temperatures, UV radiation and increasing ionic strength. The results showed that rather higher temperature has a significant impact on biopolymers stability. However, used biopolymers were hardly affected by UV radiation except BSA whose molecular weight increased considerably. Decrease of the zeta potential absolute values and the molecular size usually occurred with increasing ionic strength. The change of molecular weight was not detected.
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