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Posouzení trvanlivosti vybraných druhů dřev pro obchodovatelný výrobek
Sion, Matěj
In this thesis, the problem of the resistance of terrace boards to biological degradation. The following woods were chosen for the experiment: 1) Garapa (Apuleia leiocarpa Vog.) → is a representative of tropical woods and at the same time a species required by customers. 2) Mulberry (Morus) → a possible alternative in future years. 3) Acetylated European alder wood (Alnus glutinosa) → a possible alternative, when this method of modification appears to be very effective. The selected woods were tested according to the ČSN EN 350 standard for resistance to the wood decay fungi of white rot (Trametes versicolor) and brown rot (Gloeophyllum trabeu) and Coniophora puteana). The second part of this thesis was the determination of the total content of extractive substances (ES), phenolic substances (FS), carbohydrates (C), and pH values of aqueous leachate selected wood species. All samples were tested and compared with each other. The wood of the mulberry tree was evaluated and as to how these properties change along the radius of the trunk. The selected woods have been found to be suitable for decking. Weight losses (white and brown rot) were in negative values, so the fungi were not able to attack the wood and it was classified in durability class 1 "very durable". From the point of view of chemical composition, it was found that the most chemical substances are contained in the wood of the mulberry tree, garapa, and the least acetylated alder. In the case of the mulberry tree, it was also found that the amount of chemical substances varies depending on the position along the stem radius. The high resistance of garapa and mulberry to wood-rotting fungi is mainly caused by the content of chemical substances. The resistance of acetylated alder was due to the acetylation process.
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Development of fortified gluten-free cereals for specific nutrition
Dohnalová, Radka ; Fialová, Lenka (referee) ; Márová, Ivana (advisor)
The bachelor thesis was focused on the development of enriched gluten-free cereals for special nutrition. The fortified cereal product included processed microbial biomass, either as a freeze-dried powder or as an extract, for which the phenolic content, antioxidant content and protein content were determined. The theoretical part includes findings from professional literature on gluten-free cereals, pseudocereals and their chemical composition. Subsequently, a review on microalgae and yeasts was prepared including a list of their metabolites. The literature search focused on green microalgae and carotenogenic yeasts. In the experimental part, the characterization of the selected pseudocereals and optimization of the prepared extracts of the selected microalgae and carotenogenic yeast were firstly carried out. The selected pseudocereals were amaranth, buckwheat and quinoa. The green microalgae strain Chlamydomonas reinhardtii and the carotenogenic yeast strain Cystofilobasidium macerans were selected for enrichment of the pseudocereals. Carbohydrates, proteins, fatty acids, -glucans, gluten, vitamins, phenolic substances, flavonoids and antioxidants were determined in the pseudocereals. Total fatty acids, lipophilic substances, phenolic substances and total antioxidant activity were detected in the microbial biomass. Finally, mixed cereal products were prepared from pseudocereal flour, microbial biomass and microbial extract. The cytotoxicity of the selected extracts was determined by MTT assay. It was found that the addition of algal biomass alone or algal extract to cereal flours resulted in a significant increase in protein. The yeast ethanol extract increased the phenolic and antioxidant content of the cereal products.
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Possibilities of using spices in the production of ham salami
Vershinina, Alina ; Szotkowski, Martin (referee) ; Mikulíková, Renata (advisor)
This bachelor's thesis focuses on the possibilities of using different spices, specifically cumin, nutmeg, allspice and marjoram, in the production of ham cuts. The aim of the work is to investigate the effect of these spices on the taste, aroma and other sensory properties of the ham cut and to assess their contribution to improving the overall quality of the product. The methodology includes the collection of samples of ham cut with various additions of spices, the performance of sensory analysis and chemical analysis for the identification and quantification of phenolic substances present in individual spices. Subsequently, the results will be evaluated and their significance for the production of ham cuts will be discussed. The results of this work could contribute to a better understanding of the use of spices in the production of meat products and provide data for the optimization of recipes and processes in the food industry.
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Accumulation of phenolic compounds in Spirogyra in stress conditions
Ráček, Jan ; Pichrtová, Martina (advisor) ; Procházková, Lenka (referee)
Phenolic substances represent one of the major groups of secondary metabolites of higher plants that play a role in a number of biotic and abiotic interactions. Among algal groups, these substances are produced, for example, by conjugating algae (Zygnematophyceae), which are currently considered to be the closest living relatives of higher plants. The common function of phenolic substances is protection against the harmful effects of ultraviolet radiation, or even an excessive amount of photosynthetically active radiation, which was supported by the induction of their synthesis after exposure to UV radiation in several ecophysiological studies. However, the range of applied stress factors and their effect on changes in phenol levels is limited. In this diploma thesis, the genus Spirogyra, for which the chemical structure of a number of specific phenolic substances is known, was exposed to selected stress factors and their influence on cell morphology, maximum quantum yield Fv/Fm and quantity of phenolic substances was monitored. A significant increase was observed after application of UV-B radiation, higher level of PAR, low temperature and osmotic stress, while at high temperature this effect was not evident. Increased production upon UV-B exposure further underlines the importance of phenolic...
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Isolation and characterization of beta-glucans of natural origin
Ratsilouskaya, Lizaveta ; Hoová, Julie (referee) ; Márová, Ivana (advisor)
The bachelor thesis deals with the characterization of natural beta-glucans and other active substances isolated from macroalgae and yeasts. The used macroalgae samples differ in the pigment, origin and method of algae processing. The theoretical part focuses on seaweed and yeast species, beta-glucans, their sources and biological effects, other biologically active substances (such as polyphenols and antioxidants) and finally on methods for determining these biologically active substances. In the practical part, samples of selected macroalgae were analyzed, namely samples of Arame, Nori, Kombu, Wakame, Hijiki and Spaghetti. Aqueous, ethanol and acetone extracts of these algae were prepared in this work. The aqueous extracts were used for spectrophotometric determination of phenolic substances, flavonoids and antioxidant activity by the ABTS method. Furthermore, ethanol and acetone extracts of said macroalgae were used to determine total chlorophyll and carotenoid content spectrophotometric. The work also focused on beta-glucan content, analyzing macroalgae and yeast R. toruloides. Arame and Nori algae and R. toruloides were high in beta-glucans. However, beta-glucans were very low in other macroalgae.
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Pretreatment of hops for further processing in beer technology
Tichá, Anna ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with pre-treatment of hops for further processing in beer technology. In the experimental part of the work, the effect of low temperatures, as pre-treatment of hops, on the monitored parameters was observed. Three types of cold pretreatment were used. In two cases, the hop material was frozen using a freezer at -25 ° C and in the second case at -70 ° C. In the third case, the hop material was treated by contact with liquid nitrogen in combination with mechanical treatment. The variety of hop materiál was Žatecký poloraný červeňák, which were in the form of pellets or pressed hop cones. The total bitterness of the samples, the total content of phenolic substances, the total content of flavonoids, the antioxidant activity and the concentration of essential oils, specifically myrcene humulene and geraniol, were examined. The effect of pre-treatment was investigated during conventional worth boiling as well as dryhopping. The experimental part includes descriptions of the hopping process, descriptions of individual analytical methods. A parallel measurement was performed on each sample. Significant advantages or disadvantages of some of the pretreatments were not demonstrable, however, the most significant differences were observed in samples hopped with hops pretreated by freezing at -70 ° C, which had a positive effect on the amount of extracted essential oils during cold hops.
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Determination of selected phenolic and volatile substances in tea and tea infusion
Stará, Kristýna ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the determination of phenolic substances and volatile substances in teas and tea infusions. The work compares teas based on their production technology and country of origin. Phenolic substances were determined by LC / MS. Phenolic substances were divided into catechins and other substances. In methanol extracts, green teas contained higher concentrations of catechins than black teas. From the group of catechins, the highest concentration was found for epigallocatechin gallate in green tea, namely 7,96 mg / g. Black teas contained the most gallic acid of the studied teas. The highest content of gallic acid in black teas was set at 1,84 mg / g. Tea infusions were prepared according to the classic procedures typical for each type of tea. In the infusions, the concentrations of all substances were higher in black teas. Some substances such as gallocatechin gallate, quercetin, coumaric acid and kaempferol were not detected in the infusions of green tea. Volatiles were analyzed by HS-SPME-GC-MS. The aroma of the tea was characterized by the identification of volatile substances in tea leafs. The black teas were characterized by a rich floral and sweet aroma. The green teas were more of a fresh and grassy aroma. The substances linalool, linalyl anthranilate and -Terpinyl acetate were found in all teas.
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Basic chemical characteristics of cranberry juice
Cao, Ha Thuy ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
This bachelor thesis is about lingonberries and cranberries. It is mainly about berries which were used for chemical analysis. The berries are from the Research and Breeding Institute of Pomology Holovousy Ltd. and they have delivered six cultivars of lingonberries and three cultivars of cranberries. There is a research of general information about classification, botanical description, important chemical substances such as vitamins, natural colorants and products made in the industry. Furthermore there is descriprion of chemical methods for basic analysis. The next part of bachelor thesis is about how all these methods were applied to berry juice. What instruments and chemicals were used. First assessment was profit of juice which was about 50,00–60,00 %, but lingonberry Runo bilawskie has at least 31,49 % and cranberries have less profit too. Total solids were determined in the range of 11,40 % (Pilgrim) to 18,50 % (Runo bielawskie) and solitable solids are in range of 10,00 % (Pilgrim) to 16,08 % (Korál). Lingonberry contains more reducing sugars (8,81–12,92 %) than cranberry (7,90–9,03 %). Titratable acids are about 32,04–49,60 mmol.l-1 for lingonberry and about 55,40–60,67 mmol.l-1 for cranberry. The measurements show that pH of both berries are about 3. The most phenolic substances are found in range of 2187,11–3476,75 mg.l-1. Berries content anthocyans colorants in range of 54,91-65,29 mg.l-1 and the most in cranberry. All results are shown in charts and in the end there is a discussion and conclusion about methods and results.
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Possibility of further use of elderberry marc
Sedláčková, Lucie ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis talks about the production of concentrates and lyophilisate from the extract of elderberry moldlings (elderberry, Sambuvus nigra L.) and by determination by chosen chemical characteristics of these products. The theoretical part includes the botanical characteristics of the plant species Sambucus nigra L. Next is the part that is dedicated to biologicaly active substances found in elderberry and it‘s possible usage in the food industry. Next is the part where the extraction, purification and indentification of anthocyanic dyes are described. In the next part is the analyrical method HPLC described, including the description of instrumentation. The last part talks about the description of the used methods: methods for the concentration of the extract, UV-VIS spectrophotometry, determination of phenolic compounds, determination of dry matter, determination of active acidity and the overall titrating acidity. The experimental part contained the optimalization of the process of producing the extract from elderberry moldings. The extract obtained was then concentrated for preservation and characterization purposes based on selected chemical properties. The total content of anthocyanin dyes was chosen as a quality parameter. The most suitable process for the preparation of the extract was chosen to be the ratio of moldings and solvent 1:2, 4 (m/V). The most suitable solvent was chosen to be a mixture of water and ethanol in a ratio of 1:1 (V/V). According to the needs of the submitter, an extract with the use of water as the extraction agent is also provided. The prepared extract was then concentrated on a vacuum evaporator or lyophilized for storage purposes. The dye degradation while using the evaporator was the lowest in a 40 ° C water bath. The final products were characterized by the determination of soluble solids, pH, titration acidity, total phenolic compounds and total anthocyanin dyes. The anthocyanin pigments contained identified by liquid chromatography are: cyanidine-3-sambubioside, cyanidine-3-glucoside, cyanidine-3-sambubioside-5-glucoside, and cyanidine-3,5-diglucoside The total content of anthocyanins in the concentrate was determined to be equivalent to cyanidine-3-glucoside at 2.8 gl-1 and in the lyophilisate 2.5 gl-1.
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Phenolic substances in algae
Ráček, Jan ; Pichrtová, Martina (advisor) ; Pilátová, Jana (referee)
Phenolic substances are considered to be a group of secondary metabolites, known primarily from land plants (Embryophyta). Their function is to absorb harmful ultraviolet radiation, to protect plants from grazing and to attract pollinators and seed spreaders. However, these compounds have also been reported in some phylogenetically unrelated algal groups, the most important of which are brown algae (Phaeophyceae), siphonous green algae from the Dasycladaceae family and conjugating algae (Zygnematophyceae). The aim of this work is to summarize the current knowledge about phenolic compounds of these groups with an emphasis on their significance for the biology of the species. The first part describes phenolic compounds in general and also outlines the way they are biosynthesized. The next chapters then deal with the three algae groups. The most explored ones in this area are brown algae, which contain a unique type of tannins called phlorotannins in their thallus. This is followed by green siphonous algae from the family Dasycladaceae, which synthesize sulphated coumarins and then conjugating algae in which gallic acid-based phenolic compounds have been found. The common feature of these substances is, as with land plants, the ability to absorb radiation from the ultraviolet part of the spectrum and...
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