|
|
Isolation of antimicrobial compounds from spent coffee grounds
Kurzová, Pavlína ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
Coffee grounds are one of the very valuable lignocellulosic wastes that have been able to be processed and used for isolated phenolic substances. Many phenolic substances isolated from lignocellulosic wastes have antimicrobial properties. Aim of this thesis is isolation phenolic substances from spent coffee grounds extract and their available antimicrobial properties. Two isolation ways were applied to receive phenolic substances from spent coffee grounds: 1) solvent extraction (hexane, 75% ethanol, 70% acetone, diethyl ether, and ethyl acetate) and 2) release of active substances by alcoholic fermentation. All isolated materials were characterized by the viewpoint of concentration of reducing sugars, polyphenols and flavonoids. Subsequently, their antimicrobial activity was determined by using agar diffusion and broth dilution methods. Two gram-positive bacteria (Bacillus subtilis and Micrococcus luteus), one gram-negative bacteria (Serratia marcescens) and two yeasts (Candida glabrata and Saccharomyces cerevisiae) were used for antimicrobial testing. High-performance liquid chromatography (HPLC) was used to identify phenolic substances in the extracts. First, the results showed that the isolated sample with the highest antimicrobial activity was 70% acetone extract. This extract contained chlorogenic acid, gallic acid, caffeic acid and coumaric acid according to HPLC. The ethyl acetate extract showed the lowest antimicrobial activity. Second, after lyophilization, the isolated materials also revealed high antimicrobial activity. The highest antimicrobial activity displayed the materials obtained by the extraction with 70% ethanol. This sample contained chlorogenic acid, gallic acid and caffeic acids. Next, samples with phenolic compounds were obtained by the alcoholic fermentation of spent coffee grounds. These samples showed similarly to the previous solution extracts significant antimicrobial activity. Interestingly, the unfiltered samples received directly after alcoholic fermentation also showed antifungal properties. The characterization of phenolic compounds by HPLC showed similarly as in previous examples that chlorogenic, caffeic and gallic acids were present in these samples.
|
|
|
Hevlín – place in the landscape
Javůrková, Terezie ; Veselá, Markéta (referee) ; Foretník, Jan (advisor)
The diploma thesis deals with the urban structures of Hevlín, solves mainly the area of the current centre and the specific design of housing for the elderly and the medical house. After the bombardment of Hevlín at the end of World War II, an empty space was created in the urban structure, which became a square. However, its scale does not correspond to the urbanism of Hevlín, nor to the scale of human. A large space belongs to transport, parking and greenery, not to people. The aim of the work is to create a conceptual design of public spaces in the current centre of Hevlín. The aim of more detaild design of housing for the elderly and the medical house try tu interpret the attributes of a village house and at the same time reflect the current need of living.
|
|
|
Study of natural compounds of elderberry flowers
Pončíková, Alžbeta ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis was to determine the concentration of bioactive substances such as polyphenols and flavonoids and also the total antioxidant capacity in extracts from flowers of elder. The second part was the subject of an experiment to determine the antimicrobial activity. The theoretical part deals with the description of individual bioactive substances, the description of the elder and the bacteria used. In the experimental part, aqueous extracts were prepared, in which total polyphenols, flavonoids and oxidizing activity were determined. The results of the determination of polyphenols and flavonoids show that in order to achieve a higher content of flavonoids and polyphenols, it is more appropriate to use the highest possible initial temperature for leaching the base flower. No significant differences were found when comparing the antioxidant activity of solutions from the average values. The extracts did not show significant antimicrobial activity.
|
|
|
Obtaining and complex charaterization of Aronia spp. extracts
Seidlová, Kateřina ; Zemanová, Jana (referee) ; Veselá, Mária (advisor)
Aronia (Aronia melanocarpa) is a berry fruit with distinctive sensory characteristics and health-promoting properties. Polyphenols are the main bioactive compounds found in aronia including natural pigments – anthocyanins. Bioactive compounds are usually obtained from natural materials by extraction, in this work, two methods of extraction were compared – maceration and PHWE. Based on the total phenolic content, maceration was chosen as a more suitable method and then was optimized with statistical model – Design of Experiment. Optimal conditions were set to temperature of 30 °C, extraction agent 50 % ethanol, solid-solvent ratio 10 g per 50 ml and time of extraction for 30 minutes. Extract obtained under these conditions was characterised by total phenolic content – 1441 ± 90 mg/100 g DW, total anthocyanin content 943 ± 8 mg/100 g DW and antioxidation activity by ABTS 24,78 ± 0,09 molTE/g. In total of 25 volatile compounds were indentified in the optimal extract with content > 0,5 %. Major part created aldehydes and esters, with the main compounds being benzaldehyde (32,25 %) and methyl hexanoate (21,37 %).
|
|
|
Hevlín – place in the landscape
Kubíčková, Karolína ; Veselá, Markéta (referee) ; Foretník, Jan (advisor)
The aim of the thesis is to create a landscape that supports water retention and helps the river Dyje to create a branched, meandering watercourse. The design also deals with the permeability of the territory and the design of wooden objects that respond in function and shape to the created landscape.
|
|
|
Determination of antimicrobial activity of berry fruit extracts
Procházková, Lucie ; Veselá, Mária (referee) ; Vítová, Eva (advisor)
The goal of this bachelor´s thesis was the determination of effect of model sample of chokeberry extract (Aronia melanocarpa) on selected types of microorganisms (bacteria Bacillus cereus and Escherichia coli, yeast Candida glabrata). Two commercially available samples of natural extracts from raspberry and cocoa were selected and analysed for comparison. Theoretical part is focused on characteristic, composition and properties of mentioned plant materials, there are also listed their uses in pharmacy, medicine and cosmetics and possible methods of determination of antimicrobiological activity. Analysed commercially available samples of raspberries and cocoa don´t show any antimicrobial activity to selected microorganisms with the exception of 100% raspberry extract on Candida glabrata. There was growth promotion of colonies in the surroundings of the extract in other microorganisms. Ethanol extract of chokeberry fruits showed growing antimicrobial activity with increasing concentration of the extract. The strongest potential was observed in yeast Candida Glabrata and in bacteria Bacillus cereus. The bacteria Escherichia coli was completely resistant.
|
|
|
Smart edible films sensitive to pH
Jarošová, Gabriela ; Kovalčík, Adriána (referee) ; Veselá, Mária (advisor)
This bachelor thesis is focused on smart edible films sensitive to pH. The theoretical part deals with smart packaging including legislation. The main compound for the film preparation is chitosan, which is described and anthocyanins serving as the color indicator. At first, the anthocyanins were isolated from red cabbage using extraction. The edible films were prepared from chitosan, corn starch and anthocyanins. Pentasodium triphosphate was used as a crosslinking agent. The layers were subjected to the solubility test, which showed smallest decrease in case of fast drying in the dryer, namely 14,5 %. The color reaction on the pH change was studied. It was found that the prepared layers reacted to every pH change, the most significant reaction was to pH 1 and 3.
|
|
|
Smart food polymer layers
Valíková, Michaela ; Kovalčík, Adriána (referee) ; Veselá, Mária (advisor)
Smart packaging represents a group of packaging with great potential when used in the food industry. Active packaging can have a positive effect on the condition of stored food and smart packaging can inform consumers about the condition of stored food. In the theoretical part, a search was made on the topic of packaging in the food industry, with emphasis on active and intelligent packaging, including the legislative framework. The substances from which smart packaging is made have been described. In the experimental part, partially water¬insoluble polymer layers were prepared from gelatin, glycerol, crosslinking agent and anthocyanin extract. Glutaraldehyde or tannic acid was used as a crosslinking agent. Anthocyanins were obtained by extraction from red cabbage. The total concentration of anthocyanins in the extract was determined by the difference method. For prepared layers, their water solubility was measured and the colour response to the pH environment was evaluated spectrophotometrically. The stability of the layers over time was also monitored. It was found that the prepared layers are able respond to changes in pH.
|
|
|
Determination of antimicrobial activity of herbal extracts
Žitková, Barbora ; Veselá, Mária (referee) ; Vítová, Eva (advisor)
The aim of this bachelor thesis was to observe the antimicrobial activity of selected herbal extracts and essential oils against three selected microorganisms, bacteria – Bacillus cereus, Escherichia coli and the yeast Candida glabrata. Two diffusion methods were used to verify and compare the antimicrobial activity, namely the diffusion well and disk method. The theoretical part describes the characteristic of plants from which extracts and oils were made. It also focuses on active substances, vitamins and minerals contained in herbs. Other methods that can be used to determine antimicrobial activity are also mentioned in the work. At the end of the theoretical part the characteristic of the microorganisms used for observation is mentioned. The result of the diffusion well method shows that only eucalypt oil showed antimicrobial activity against all selected microorganisms. It was most effective against Bacillus cereus with an inhibition zone size of 1.73 ± 0.11 cm. The result of the diffusion disk method shows that there are two oils which showed antimicrobial activity against selected microorganisms, namely marrow and eucalypt oil. Nevertheless, the most effective oil was made of mint against Bacillus cereus with an inhibition zone size of 1.57 ± 0.31 cm.
|
|
|
Individual and collective care of two years old child - developmental advantages and risks
Benešová, Markéta ; Šulová, Lenka (advisor) ; Veselá, Michaela (referee)
This bachelor thesis summarizes key factors influencing the quality of care for a two - year - old child and his or her psychological development in relation with a specific type of care. The section of literature overview deals with defining central areas in development of a two - year - old child. Further, this thesis focuses on individual care of a two - year old - mainly epitomizes parent characteristics, describes initial interaction between mother and child, specifies father's role and other forms of individual care . Final section of the thesis provides an overview of types of collective care in the Czech Republic, although gives examples of several collective care systems in these foreign countries: France, Germany, Finland, Great Britain and the USA. The concl usion examines selected research studies concerning collective care for a two - year - old child and maps factors relating to the quality of collective care , which prove s to be crucial for the child's psychological development. The research project proposal is correlation research. The aim of the research is to compare the quality of the interaction between the mother and the two - year - old child in individual care and the mother and the two - year - old child in collective care. For research purposes, the Emotional Availability...
|
guest ::
RSS feed.