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Desiccation in green algae: mechanisms and aquisition of tolerance
Belza, Václav Cedrik ; Pichrtová, Martina (advisor) ; Němcová, Yvonne (referee)
This thesis summarizes the current knowledge of the mechanisms that allow green algae to tolerate even severe desiccation. It provides a comprehensive overview, ranging from the definition of desiccation stress and its impacts on algal cells, through mechanisms that algae employ in defense, to the evolutionary background as well as a synthesis of recent research on the acquisition of desiccation tolerance and factors conditioning it. The first chapter defines the desiccation stress itself and breaks down the processes by which it can damage algal cells, including both morphological and physiological effects. The second chapter discusses diverse mechanisms involved in protection against desiccation. From mechanisms aimed at prevention of water loss (e.g. mucilage production or modification of cell wall permeability), through mechanisms that cause desiccation tolerance (e.g. accumulation of antioxidants, stabilization of proteins and phospholipids etc.), to the formation of resilient life stages. The third chapter is devoted to the evolutionary-historical background behind the emergence of desiccation tolerance per se and overview in which algal groups it is observable today. The last section is a synthesis of modern knowledge regarding acquisition of desiccation tolerance during algal life and...
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Effect of biostimulants on growth and defence reactions in plants
Vlčková, Denisa ; Ryšlavá, Helena (advisor) ; Innemanová, Petra (referee)
Biostimulants are microorganisms or substances of natural origin that promote plant growth and defence against abiotic and biotic stress. The mechanism of action of biostimulants is still a subject of research. In this work, two biostimulants were studied: fermented nettles and vermicompost leachate. Both biostimulants possessed soluble proteins with lower relative molecular weights and peptides, carbohydrates, phenolic substances as well as active proteolytic enzymes and glycosidases. After application of biostimulants to the maize plants (Zea mays L.), growth parameters did not change significantly, but the plants had higher content of proteins and phenolic substances, higher antioxidant capacity and activity of some peroxidase isoforms. The effect of drought on plant growth, metabolism and antioxidant system after application of fermented nettles and vermicompost leachate was also studied. Maize plants under drought stress treated with biostimulants were able to maintain higher water content, showed higher content of proteins, phenolic compounds and higher glutathione reductase activity than untreated stressed control plants. Both tested biostimulants affected the metabolism of drought-stressed maize plants, with the positive effect being more pronounced in the lower-humus soil. Key words:...
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Production of agar candy with the addition of plant extract
Kameníková, Magda ; Gross, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the optimization of the production of jelly confectionery with agar as gelling agent, application of herbal extract to the prepared confectionery and subsequent identification of the content of aromatic active substances, characterization of phenolic content, antioxidant and antimicrobial activity and sensory quality. Calendula officinalis was selected as the source of the herbal extract, which is known for its high content of bioactive compounds. Determination of aromatic compounds was carried out by gas chromatography with mass detection, antioxidant activity by DPPH method, antimicrobial activity by diffusion method, determination of total phenolics by Folin-Ciocalteu method and sensory analysis was also carried out. Based on the sensory analysis, the optimum added amount of agar, extract and citric acid was determined. The additions of 1,25 % agar and 1 % acid were found to be optimal. The most sensory acceptable sample was the one without extract, while the sample with extract was the one with 4 % extract. The sample with Calendula extract of the above-mentioned optimal composition contained 14 identified aromatic compounds, of which guaiol, -cadinol and -muurolol were the most abundant; the total phenolic content was 464.30 ± 14.99 µgGAEg-1, and the antioxidant activity was determined to be 1.73 ± 0.01 mgTEACg-1 (or a radical quenching of 74.36 %). The antimicrobial effects of the above extract were tested against Gram-negative Escherichia coli and Gram-positive Bacillus cereus. The highest antimicrobial activity was exhibited by the extract alone and among the samples, it was the sample containing 4 % of the extract. The extract appeared to be more effective against B. cereus than E. coli. The results show that the content of extract in the samples increases their nutritional value and antimicrobial efficacy (increases the content of antioxidant and phenolic compounds).
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Optimization of Combined Chitosan Particles and their Characterization for Cosmetic use
Mrůzková, Barbora ; Dzurická, Lucia (referee) ; Bendová, Agáta (advisor)
The bachelor thesis focused on optimizing preparation and characterization of chitosan coated liposomes with selected active substances and their use for cosmetic applications. The theoretical part of the thesis describes natural substances, their effect on the skin, encapsulation methods, and the preparation and use of liposomes and chitosomes. In the experimental part, the optimization of the preparation of liposomes and chitosomes and their subsequent characterization by measuring particle size, polydispersity index, zeta potential, encapsulation efficiency and gradual release of active substances were performed. The selected active substances in this work were vitamin C, -carotene, caffeine and vitamin E. From the data obtained, the method of adding liposomes dropwise into the 2% chitosan with a short mixing time and ultrasonication for 1 minute was selected as the most suitable method for the preparation of chitosomes usable in cosmetics. Furthermore, the encapsulation efficiency of the particles and the antioxidant capacity of vitamin C, -carotene, caffeine and vitamin E were compared. The best antioxidant properties were determined for vitamins C and E; therefore, the gradual release of chitosomes with these active substances was subsequently measured in an environment simulating cosmetics. At the end of the work, cosmetic emulsions and gels containing selected chitosomes were prepared and tested on the skin by determining changes in desquamation.
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Interaction of yeast and microalgae extracts with cell cultures
Serikbay, Adilkhan ; Holub, Jiří (referee) ; Márová, Ivana (advisor)
The objective of this bachelor thesis was to optimize the extracting of bioactive compounds from microorganisms for the purpose of characterizing and evaluating their cytotoxicity on human cell line HaCaT. During the characterization phase, extract samples were analyzed using spectrophotometric techniques. After exposing the cell line to selected extracts, a cytotoxicity test was performed to assess cell viability using MTT analysis. The theoretical part encompassed an extensive literature review focused on cultivation techniques, human cell lines, cytotoxicity analysis, and viability assessments. The practical section provided a detailed exploration of contemporary extraction techniques utilizing a wide range of both polar and non-polar solvents to enhance the efficiency of extracting active compounds from the yeast strain Rhodotorula toruloides and microalgae Chlorella vulgaris. Active compounds such as ubiquinone, ergosterol, lycopene, and torularhodin were identified in the yeast, while the microalgae were found to contain lutein, chlorophylls, as confirmed by HPLC analysis. The biocompatibility of the optimized extracts from selected strains was verified using the MTT assay on HaCaT cell lines. The aqueous extract from microalgae Chlorella vulgaris exhibited lower toxicity to HaCat cell line, with viability rates exceeding 85%. Yeast extracts from Rhodotorula toruloides initially showed higher viability rates, which, however, decreased with increasing extract concentrations.
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Development of cereal products for specifc nutrition with addition of fruits and vegetables
Růžičková, Magdalena ; Kubalová, Michaela (referee) ; Bendová, Agáta (advisor)
This bachelor thesis focuses on developing gluten-free cereal products for special nutrition. The main focus is on increasing the concentration of phenolic compounds and antioxidants in cereals by adding fruit and vegetable components. The theoretical part includes findings from professional literature on cereals, gluten-free cereals and their chemical composition. A chapter devoted to celiac disease and gluten-free diet was also included. Furthermore, the theoretical part focuses on possible methods of enrichment and also on selected fruits and vegetables used in the experimental part. In the experimental part, five samples of gluten-free cereals were analysed, namely black, red, brown and white rice and corn. The concentration of flavonoids, polyphenols, antioxidants, carbohydrates, proteins, -carotenes, anthocyanins, gluten, -glucans, fatty acids and lipophilic vitamins was determined in the cereal samples. Selected samples were also tested for antimicrobial activity. The black rice sample showed the best results in the majority of the measurements. Selected samples of eight types of fruit (cranberry, raspberry, strawberry, blueberry, blackcurrant, mango, banana, kiwi) and four types of vegetables (broccoli, carrot, green pea, beetroot) were also analysed. The concentration of flavonoids, polyphenols, antioxidants, carotenes, anthocyanins, ascorbic acid and lipophilic vitamins was determined in these samples. Antimicrobial tests were performed on selected fruit and vegetable samples Among the fruit samples, the best results in the majority of measurements were in blueberry and blackcurrant samples. Among the vegetable samples, the best results were obtained from the beetroot sample. From the best cereal, fruit and vegetable samples were created porridges as a final product. In these samples, the concentration of polyphenols and antioxidants was determined. The highest concentration of both compounds was found in the porridge with black rice and blueberry.
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Posouzení subchronické toxicity směsí pesticidů na raky
HOVORKOVÁ, Anna
Prometryn, belonging to the group of s-triazines, has been extensively used in the case of protection of maize production against broadleaf weeds and grasses. Its use was banned by the EU in 2004. Chloridazone is a pyridazone herbicide used to protect beet production and to control broadleaf weeds. Its properties increase the potential for the transfer of this pesticide to the aquatic environment. Together with its metabolites, it has been detected in groundwater in the Czech Republic. Its use in the Czech Republic has been banned since 2020. The adventitious properties and long-term use of these substances may increase the risk of contamination of non-target ecosystems by the pesticides used and their metabolites, which may form mixtures in this environment and thus have an even riskier impact on the environment. The aim of this work was to assess the subchronic toxicity of the pesticide mixture formed of the concentrations of these pesticides on the signal crayfish (Pacifastacus leniusculus) in comparison with the control and pesticides tested alone. A subchronic toxicity test of 20 days duration followed by 10 days depuration was used to obtain the results. The criteria evaluating the toxicity of the mixture were the biochemical profile of haemolymph, oxidative stress level and antioxidant enzyme activity from hepatopancreas, muscle and gill samples. The biochemical profile of haemolymph was significantly affected in individuals tested in the pesticide mixture. For biomarkers altered due to the mixture, suppression of the effect of prometryn in the mixture was observed in some cases. The analysis of antioxidant biomarkers did not show a higher toxicity of the mixture over the pesticides tested alone. In the case of antioxidants, a greater effect was observed for prometryn tested alone, where in some cases its presence in the mixture suppressed the effects of chloridazon in the mixture.
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Jelly candies with the addition of bilberry (Vaccinium myrtillus) extract
Knapovská, Pavlína ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This thesis deals with the application of bilberry fruits (Vaccinium myrtillus) and their extract to jelly candies and the subsequent characterization of these candies in terms of volatile compounds, total phenolic compounds and anthocyanins, antioxidant activity and sensory quality. The volatiles were determined by headspace solid-phase microextraction coupled to gas chromatography with mass spectrometry and standard spectrophotometric methods were used for the determination of bioactive compounds. Total phenolic content was determined by the Folin-Ciocalteu method, antioxidant activity by the TEAC method and total anthocyanin content by pH differential analysis. The sensory quality of the samples was evaluated using unstructured graphical scales. The preparation of the bilberry extract was optimized on the basis of total phenolic content and the following conditions were selected as the optimal: a weight of 1000 grams of bilberries per litre of water, a temperature of 50 °C, and an extraction time of 2 hours. The optimum additions to candies were selected, by sensory analysis, as 25 wt. % of extract and 15 wt. % of bilberries. A total of 45 volatile compounds were identified in the candy with bilberry extract, the most abundant being (E)-9-hexadecen-1-ol (22,7 %), furfural (10,9 %) and 2-ethylhexan-1-ol (10,0 %). The total phenolic content was 1141 ± 11 gGAE · g-1, the antioxidant activity was 660 ± 66 gTE · g-1 and the total anthocyanin content was 418 ± 23 gC3G · g-1. A total of 40 volatile compounds were identified in the candy with bilberry and the most abundant were linalool (22,7 %), (E)-9-hexadecene-1-ol (16,1 %) and 2-ethylhexan-1-ol (8,4 %). The total phenolic content was 1735 ± 56 gGAE · g-1, the antioxidant activity was 1109 ± 32 gTE · g-1 and the total anthocyanin content was 745 ± 23 gC3G · g-1. With the addition of both the extract and the bilberries, the candies showed a significant increase in bioactive and volatile compounds content, and the colour and flavour of the enriched samples were positively evaluated, thus improving their overall acceptability.
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Optimizing the production of non-chocolate sweets with the addition of Filipendula ulmaria extract using various sweeteners
Malyszová, Markéta ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
The aim of this master's thesis was to optimize the production process of jelly candies using various alternative sweeteners and subsequently adding herbal extract of meadowsweet, achieving not only better nutritional properties but also enhanced sensory characteristics of the final product. Sensory analysis was utilized to determine the ideal combination of sweetener type and amount, which most closely aligns with consumer preferences for sweetness and texture, while maintaining a low energy component content. Based on these criteria, maltitol was selected as the sweetener in a 50% w/w solution. The study also focused on optimizing the addition of Filipendula ulmaria extract to the candies made with the "ideal" sweetener. Again, using sensory analysis, the optimal concentration of the extract and the type of gelling agent were selected to achieve the desired consistency, taste, and other sensory parameters that make the product attractive for consumers. Following these experiments, the ideal values were determined to be 50% w/w for sweetener, a 5 % addition of Filipendula ulmaria extract, and the use of gelatin as the gelling agent. Subsequently, a chemical analysis of the produced samples and meadowsweet extract was also carried out. Identification and quantification of volatile aromatic compounds were performed using the HS SPME GC-MS method, which identified 39 different substances, predominantly from the group of alcohols and aldehydes. To determine the total content of phenolic compounds, the Folin-Ciocalteu spectrophotometric method was used, and the pH differential method was employed to determine the content of anthocyanins. The total content of phenolic compounds in the extract amounted to 1418.16 ± 6.56 gml-1, and the total anthocyanin content was determined to be 249.19 ± 27.40 gml-1. Antioxidant activity was tested using two methods, TEAC and DPPH. The results of the antioxidant activity measured by the DPPH method were higher, confirming the greater robustness of this method. However, both tests confirmed the antioxidant activity of the tested samples. Finally, the antimicrobial activity of the samples was tested using the diffusion well method against strains of Bacillus cereus and Escherichia coli. The samples exhibited antimicrobial activity against both tested microorganisms, but showed more effective action against Bacillus cereus, which may be due to the simpler structure of their cell wall.
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Active substances in cereal products for baby food
Hurtová, Jana ; Pařilová, Kateřina (referee) ; Márová, Ivana (advisor)
Present bachelor thesis is focused on the study of antioxidant substances in cereal products for baby food. The theoretical part is aimed at describing the anatomical structure and chemical composition of cereal grain, characterization of antioxidants with the focus on natural antioxidants, the technology and nutritional parameters of cereal products. The experimental part deals with the content of phenolic compounds, flavonoids, and the total and reducing sugars in the total of 12 kinds of cereal products with different flavour – 5 types of oak pap, 3 types of fiber pap and 4 corn paps. The work includes the analysis of ascorbic acid by titration method and the analysis of tocopherol, carotenoids and catechins by high performance liquid chromatography as well. The highest content of total phenolics and flavonoids was found in corn pap with raspberries and also in cereal pap with chocolate. High levels of vitamins E and C were found predominantly in flavoured fiber pap.
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