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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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Use of some encapsulation techniques to controlled release of active substances in food and cosmetics products.
Skoumalová, Petra ; Rittich, Bohuslav (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on preparation, characterization and application of organic micro- and nanoparticles as transport systems for active components and some their complex natural sources. Active component were packed into liposomes and polysaccharide particles. As active components were used caffeine, some drugs – clotrimazole and ibuprofen, further antioxidants and vitamins. Antimicrobial herbs and spices extract, antimicrobial peptides lysozyme, nisin and other antimicrobial ingredients were encapsulated too. Encapsulation of selected hydrolytic enzymes was tested, too. Particles were also used for encapsulation of probiotic strains Bifidobacterium breve and Lactobacillus acidophilus and prebiotic components. These prebiotics were co-encapsulated into capsules with probiotic cells. Natural extracts were encapsulated e.g. extracts of guarana, ginseng, goji, green barley, propolis, black, green and white tea, coffee, fruit and vegetable extracts. The efficiency of encapsulation was determined by HPLC/PDA and by spectrophotometry. Long-term stability of particles and amount of released component in model/real foods, in model cosmetic conditions and in a model physiological environment were monitored too. Size of prepared liposomes and polysaccharide particles was determined by dynamic light scattering and by light microscopy and electron microscopy, respectively. Stability of the particles was measured using a zeta potential. Also, analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. The antimicrobial activity were tested using two Gram-positive (Bacillus subtilis, Micrococcus luteus), two Gram-negative (Escherichia coli, Serratia marcescens) bacteria and one fungal strains (Candida glabrata). For determining the antimicrobial properties of active component and prepared particles two the most widely used methods were used - agar diffusion method and broth dilution method. The viability of probiotic strains were performed using flow cytometry and fluorescence microscopy. Encapsulation of active component was successful in all types of particles. Liposome showed a very good long-term stability mainly in water conditions with neutral pH and polysaccharide particles were stable in acidic conditions. Prepared particles showed a very good stability in model stomach environment, while in model intestines environments particles were disintegrated and active component were released. Prepared particles with encapsulated caffeine as well as other tested antioxidants and vitamins could be used to modern types of energy drinks, food supplements and also for some cosmetics applications. Encapsulated antimicrobial components could be used for food application as well as for cosmetics and pharmaceutical application like antimicrobial wound formulation. Encapsulated enzymes can be used for controlled release of proteases in wound healing, as delivery systems in digestive tract and as a part of pharmaceutical preparative and food supplements for enzyme therapy. The study revealed that encapsulation of probiotics and also co-encapsulation of probiotics with prebiotics exhibited longer stability of particles and survival bacterial cells. So, prepared particles are suitable for use to food product with beneficial effects on the human body.
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Application of herbal extract to non-chocolate jelly sweets
Phi, Lan Anh ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
This master’s thesis focuses on optimization of application of herbal extracts and powder into jelly sweets and comparing them to commercial products with a same flavour. Prepared and commercial samples were then characterized in terms of volatile substances, total phenolic content, antioxidant activity and sensory quality. Volatile compounds were determined by HS-SPME-GC-MS method, a verification of validation parameters (limit of detection and quantification, repeatability, reproducibility, retention time, retention index) was part of the thesis. The total phenolic content was determined by Folin-Cicalteu’s spectrophotometric method, antioxidant activity by TEAC method and sensory quality by sensory analysis. Optimal amount of extracts and powders were selected based on the sensory analysis. For the preparation of extracts and powders were used aromatic plants lemon balm (Melissa officinalis) and ginger (Zingiber officinale). Optimal amount of extract addition was the concentration 15 %, by the next sensory analysis was determined 1 % addition of the powder for both herbs. There were 32 volatile compounds identified in a model lemon balm jelly, which of 4 were allergens (linalool, Z and E isomer of citral, citronellol, Z and E isomer of geraniol). Total phenolic content in the sample was 755,5 ± 14,3 gGAE g–1 and antioxidant activity was determined on a value 2,73 ± 0,13 10–3 mmolTE g–1. Commercial lemon balm sample contained 54 aromatic compounds from which were 5 allergens – limonene, linalool, Z and E isomer of citral, citronellol, Z and E isomer of geraniol. Total phenolic content was 695,5 ± 9,8 gGAE g–1 and antioxidant activity was 2,67 ± 0,05 10–3 mmolTE g–1. There were 26 volatile compounds identified in the model ginger jelly, which of 4 were allergens (linalool, Z and E isomer of citral, citronellol, (Z)-geraniol). Total phenolic content in the sample was 511,0 ± 12,3 gGAE g–1 and antioxidant activity was determined on a value 1,87 ± 0,16 10–3 mmolTE g–1. The first commercial ginger sample contained 55 aromatic compounds and 4 of them were allergens (limonene, linalool, citronellol, (E)-geraniol). Total phenolic content in the sample was 224,3 ± 20,2 gGAE g–1 and antioxidant activity was determined on a value 0,95 ± 0,24 10–3 mmolTE g–1. The second commercial sample contained 32 volatile compounds, which of were 4 allergens – limonene, linalool, Z and E isomer of citral and (E)-geraniol. Total phenolic content was 569,9 ± 23,2 gGAE g–1 and antioxidant activity of the sample was 3,48 ± 0,08 10–3 mmolTE g–1. In terms of sensory properties, the prepared samples which had balanced sweet and sour taste with pleasurable optimal herbal taste, were preferred by evaluators.
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Polyphenols in nutritions and their effect on DNA
Osorio, Juan ; Černayová, Diana (referee) ; Brázda, Václav (advisor)
Epidemiologické studie prokázaly vliv konzumace rostlinných potravin v prevenci široké škály nemocí. Přírodní antioxidanty přítomné v těchto potravinách, mezi nimiž jsou velmi důležité polyfenoly, mohou být zodpovědné za tuto činnost podporující zdraví. Cílem bakalářské práce je ukázat interakci určitých polyfenolů s genetickým materiálem prostřednictvím různých signálních mechanismů, zejména pokud jde o stabilizaci nekanonické struktury DNA G-kvadruplex a poukázat tak na nejselektivnější látku pro inhibici biochemických procesy. Dále práce obsahuje podrobné informace, které mohou pomoci pochopit, jak mohou polyfenolové sloučeniny interagovat s DNA prostřednictvím epigenetických mechanismů a G4 struktur, a které faktory mohou ovlivnit jejich účinnost. Různé experimenty, biologickým a experimentálním opakováním, byly použity k potvrzení interakce mezi sloučeninami a DNA.
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Characterization of antioxidative and antimicrobially active substances in some types of wood
Ďatko, Tomáš ; Hlaváček, Viliam (referee) ; Márová, Ivana (advisor)
The purpose of this bachelor thesis is to analyze antioxidant and antimicrobial active substances in woody plants. The theoretical part deals with characterization of these biologically active substances, the overview of selected types of woody plants and dividing of extraction techniques. Moreover, methods for determination antimicrobial activity were described. The experimental part is focused on preparation of bark extracts of birch, oak and willow using different solvents (water, methanol, ethanol, DMSO) at various parameters (time, temperature). The concentration of polyphenols, flavonoids, tannins and antioxidant activity was set by using spectrophotometrical method. Subsequently antimicrobial activity of extracts was tested against the three microorganisms: Micrococcus luteus, Serratia marcescens and Candida glabrata. The results show that the most antioxidant active substances are found in the willow bark and antimicrobial activity was showed very weakly in selected bark extracts.
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Biologically active substances of chokeberry (Aronia spp.)
Palkovská, Kateřina ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This master thesis deals with preparation of extracts from fruits of aronia, optimization of conditions for extraction and subsequent characteristics of the obtained optimal extract. In the theoretical part information about the botanical characteristics of Aronia melanocarpa and about its utilization are mentioned. Furthermore, the chemical composition of aronia fruits is described and the main biologically active substances contained in the plant are described. At the end of the theoretical part extraction and separation techniques, determination methods of antioxidant, antimicrobial activity and determination of aromatic active compounds are described. The experimental part describes the optimization of maceration so that the macerate contains as much polyphenolic substances as possible, as well as aromatic active substances. 40% ethanol, at a temperature of 60 ° C, with a weight solvent ratio of 1: 5, for 40 minutes proved to be optimal for the maceration of aronia fruits. The total polyphenol content of the optimal extract was determined to be 5237.2 ± 40.7 mgGAEkg-1 and the antioxidant activity by TEAC to be 512.5 ± 5.04 gml-1. 24 aromatic active compounds were identified in the extract, with the largest percentage being monoterpenes and aldehydes. Furthermore, it was found that the extract did not show antimicrobial activity against the microorganisms used (Bacillus cereus, Escherichia coli and Candida glabrata). The obtained results confirm that aronia extracts are an important source of many biologically active compounds and can be used in food as a natural source of nutritionally and sensory valuable substances.
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Preparation and characterization of plant extracts for application to syrups
Šandová, Lucie ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
The aim of the diploma thesis was to produce herbal syrups from three selected herbs of the Lamiaceae family - Salvia officinalis, Melissa officinalis and Mentha piperita. First, extracts were prepared from these herbs by maceration in 25% of ethanol (60°C, 90 min). From the prepared herbal extracts, herbal syrups were made by mixing with syrup base (65% sucrose solution + lactic acid 2 g.l-1) in different ratios (2:1, 1:1, 1:2 - extract: base of the syrup). On the basis of sensory evaluation, a ratio of 1:1 was selected as optimal. The extracts and syrups produced were characterized in terms of volatile profile, phenolic content, antioxidant activity and antimicrobial activity. The produced syrups were also evaluated sensorially using scales, profile, and order test, and compared with similar commercial samples (Baťkovy sirupy s.r.o.). The HS-SPME-GC-MS method was used for the determination of volatile substances, the Folin-Cicalteu method for total phenolics, the TEAC method for antioxidant activity and the well and disc diffusion method for antimicrobial activity. 36 volatiles were found in model sage syrup, 29 in commercial syrup; 20 volatiles were found in model lemon balm syrup, 32 in commercial syrup; 25 volatiles were found in model mint syrup, 41 in commercial syrup. The quantitative distribution of the most important compounds in the commercial and manufactured syrups differed, with terpenes predominating in all samples. The content of phenolic compounds in syrups decreased in the order sage (570.1 mg.l-1) > lemon balm (378.9 mg.l-1) > mint (96.5 mg.l-1), antioxidant activity in the order lemon balm (332.0 µg.ml-1) > sage (185.6 µg.ml-1) > mint (115.8 µg.ml-1). Commercial syrups showed significantly higher phenolic compound content and antioxidant activity than manufactured syrups for all three herbs. In terms of sensory quality, mint syrup was considered the most palatable and sage syrup the least palatable (mint > lemon balm > sage); only in the case of lemon balm was the manufactured syrup considered better, more palatable than the commercial sample. It was reasonably liquid, clear of a pleasant colour, with a distinctly sweet, slightly herbaceous taste and a pleasant aroma.
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