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Bioactive compounds of fennel
Nentvichová, Aneta ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis is to study the bioactive substances contained in fennel, to determine the content of polyphenols, flavonoids and to investigate the antioxidant and antimicrobial activity in aqueous and ethanol extracts of fennel. The theoretical part discusses the characteristics of fennel, its classification in the system, its use and especially the bioactive substances contained in it. The experimental part is divided into two sections, where the first part focuses on spectrophotometric determination of polyphenols, flavonoids and antioxidant activities. In the second part the antimicrobial effects of prepared extracts of fennel were examined. Two microorganisms Serratia marcescens and Bacillus cereus were exposed to the said extracts. Antioxidant activity and relatively high content of polyphenols and flavonoids were found in the extracts in the first experimental part. The second experimental part proved that the antimicrobial effect of the extracts was very low, in most cases almost negligible. Ethanol extracts showed higher antimicrobial activity, while hot water extracts found to support the growth of Bacillus cereus.
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Ion-selective membrane with antimicrobial effect
Gablech, Evelína ; Farka,, Zdeněk (referee) ; Soukupová,, Jan (referee) ; Drbohlavová, Jana (advisor)
Tato práce se zabývá zlepšením antimikrobiálních vlastností komerčních polymerních membrán používaných v mlékárenském průmyslu pro filtraci mléčných výrobků jako je syrovátka. Tyto membrány trpí kontaminací způsobenou mikroorganismy přítomnými v mléce během procesu filtrace. Toto biologické znečištění ovlivňuje životnost membrány i samotný filtrační proces. Pro ochranu membrány před vytvořením biofilmu z mikroorganismů byly tyto membrány modifikovány pomocí plazmových metod tak, aby došlo k funkcionalizaci aminovými skupinami pro následnou imobilizaci nanočástic stříbra a selenu. Antimikrobiální aktivita obou typů nanočástic a membrán s imobilizovanými nanočásticemi byla stanovena proti buněčným kmenům Staphylococcus aureus a Escherichia coli.
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Preparation of edible antimicrobial packaging
Kozubová, Petra ; Dzurická, Lucia (referee) ; Skoumalová, Petra (advisor)
This bachelor’s thesis is focused on preparation and characterization of eatable packaging. Eatable packaging consists of two components, antimicrobial component and base of packaging. The task of eatable packaging is to protect product against antimicrobial attack and to extend durability of the product. As antimicrobial components were used water and oil extracts of several herbs (mint, nettle, lavender, cinnamon, cloves, vanilla, ginger and rhinoceros). Oil extracts were also encapsulated into liposomes for better application. Firstly, concentrations of polyphenoles and antioxidants of extracts were determined. Oil extract of clove contained the highest concentration of both determined substances. Encapsulation efficiency, stability and size of liposomes were tested too. All prepared liposomes were stable and relatively of the same size. Also high encapsulation efficiency was observed. Next, antimicrobial activity of prepared extracts and liposome particles against yeast Candida glabrata and two bacteria strains Escherichia coli and Staphycococcus epidermidis was tested and the high antimicrobial activity reported mainly all tested liposomes. Then alginate, chitosan and carboxymethylcellulose and their combinations respectively were used as bases of packaging. Created film had to meet several parameters, especially suitable sensory properties such as pleasant taste and smell, as well as invisibility, gloss, affordability and suitable manipulability. Combination of 2% carboxymethylcellulose and 1% alginate in a ration of 2:1 with liposomes of mint as antimicrobial component achieved the best results.
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Characterization of plasma activated water for biomedical applications
Šindelková, Kateřina ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
The aim of this master thesis is to characterize plasma activated water (PAW) prepared in various plasma systems using direct and indirect interaction of plasma with liquid or its surface. Plasma was generated by electric discharges at atmospheric pressure. The prepared plasma-activated water was studied with respect to its use in biomedical applications. The theoretical part deals with plasma activated water. It contains a description of the PAW preparation, its characterization in terms of produced particles or its physico-chemical properties. Also, methods for antimicrobial activity estimation or colorimetric determination of produced particles are described in this section. In the experimental part of this work, the types of discharges that were used for the PAW preparation and their comparison are presented. Two types of liquids were selected for the activation, namely distilled and tap water. Subsequently, concentrations of selected reactive particles in PAW (hydrogen peroxide, nitrates and nitrites) produced in three different plasma systems were determined. Besides the comparison of reactive particles production in various systems, their time stability was studied as well. Over time after the PAW preparation, the values of active particles concentrations have changed due to mutual interactions between the particles. Mainly, nitrites were oxidized to nitrates or vice versa depending on the PAW type and other conditions. Part of the work was also monitoring selected physical properties of PAW, namely pH value and specific conductivity. It has been found that PAW does not retain its activated properties for too long, depending on the type of preparation and methods of storage. Therefore, one of the important goals of this work was to determine and compare suitable storage conditions for PAW with respect to its potential biomedical applications.
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Preparation and testing of application forms for natural antimicrobial substances
Vajglová, Klára ; Bokrová, Jitka (referee) ; Márová, Ivana (advisor)
The goal of this bachelor thesis was the study of antimicrobial and antioxidant effects of some herbal extracts: cloves, nettle, sage, chamomile, rosemary, elderberry, lavender and also lysozyme. Further, herbal extracts effect on Gram positive and Gram negative bacteria were compared. In the theoretical part were briefly characterized lysozyme, polyphenols, flavonoids and selected strains of microorganisms. In the experimental section characterization of herbs with antimicrobial and antioxidant effect was proved. Particles containing herbal extracts were prepared and encapsulation efficiency was determined. In some of tested herbs encapsulation efficiency of up to 80% was reached. Stability of the prepared liposomes was tested in the model digestive conditions and after 1 week and 1 month incubation period in model foods. Antimicrobial activity was tested on selected representatives of Gram negative and Gram positive bacteria. Gram positive bacteria were more sensitive to herbal extracts and liposomes containing encapsulated herbs, while lysozyme exhibited higher effect to Gram negative bacteria. Prepared particles with encapsulated antimicrobial extracts are especially suitable for use in the food industry.
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Determination of antimicrobial and antioxidant activity of selected herbal extracts
Čaková, Adriana ; Němcová, Andrea (referee) ; Vítová, Eva (advisor)
Tetradenia spp. is herb naturally growing in Africa and is part of family called Lamiaceae. The herb is used in traditional medicine to cure malaria, angina or as treatment for tropical skin diseases. Maceration was chosen from number of extraction methods, to obtain bioactive compounds from this plant. Optimization was performed with aim to retrieve as much of bioactive compounds as possible. Optimal conditions chosen were: temperature 60 °C, extraction time 40 minutes, solvent 40% ethanol and solid-solvent ratio 1:5. In total 63 aromatic active compounds were found in optimal extract. Terpenes were the most abundant (88,60 %), from them oxygenated monoterpenes (55,65 %) and monoterpenes (29,52 %). Compounds with highest percentage quantity were camphor (51,76 %), cis--ocimene (8,17 %), 3-octyl acetate (7,71 %), trans--ocimene (6,76 %), -terpinene (4,93 %), o-cymene (3,81 %), terpinolene (1,33 %), limonene (1,33 %), camphene (1,19 %) and borneol (1,20 %). Further, total phenolic content was 0,31 ± 0,02 mgGAEml-1, which equals 1,52 ± 0,11 mgGAEg-1 of plant. Antioxidant activity was 417,56 ± 32,84 gTEACml-1 and percentage of radical scavenging activity ABTS•+ was 88,99 ± 7,00 %. Finally antimicrobial activity was determined against bacteria Bacillus cereus, Escherichia coli and yeast Candida glabrata. Against E. coli and C. glabrata there was no inhibition exhibited. Against B. cereus there was seen mild inhibition activity. The results confirm that Tetradenia spp. contain a number of interesting aroma active compounds, which shows antioxidant and antimicrobial activity. The herb has a good potential as natural source of nutritious and sensory active compounds to be used into various foods.
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Rosehip – the source of natural compounds
Motúzová, Eliška ; Vítová, Eva (referee) ; Veselá, Mária (advisor)
The goal of this bachelor thesis was to study the antimicrobial activity of various extracts of rosehip tea. As well as to determinate concentration of biologically active compounds, polyfenols and flavonoids, and antioxidant activity in these teas. Teoretical part describes basic information about Rosa canina, general classification of tea, summary of biologically active compounds and basic methods of extraction. Practical part is focused on determination of anioxidant acivity, comcentration of polyfenols and flavonoids in tea extracts and detection of animicrobial activity of these extracts against bacterial strains Serratia marcescens and Micrococcus luteus. The results of this theasis show that aqueous extracts of rosehips tea are animicrobialy active. It was also found, that these extracts have hight contents of polyphenols and flavonoids.
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Characterization of the genus Plectrantus for use in the food industry
Chmelová, Nikola ; Diviš, Pavel (referee) ; Vítová, Eva (advisor)
The aim of this diploma thesis was to determine the optimal extraction conditions for obtaining an extract from the plant Plectranthus amboinicus. Plectranthus amboinicus is an aromatic herb of the Lamiaceae family containing a large number of bioactive compounds. Because of this, it has a number of biological effects – antimicrobial, anti-inflammatory, antioxidant, analgesic, etc. To maintain the maximum of sensory and nutritionally valuable components of P. amboinicus, a simple maceration of fresh chopped herb was chosen. Maceration was performed under the following conditions: 40 minutes at 40 ° C, solvent 40% ethanol, weight 20 g of herb per 100 ml of solvent. The extract prepared under these optimal conditions was comprehensively characterized in terms of the content of total polyphenols, their concentration was determined to 0,08 ± 0,02 mgGEA·ml-1, which corresponds to 0,40 ± 0,07 mgGEA·g-1 of the plant. The antioxidant activity of the extract was 241,24 ± 29,24 µgTEAC·ml-1 and the radical scavenging activity of ABTS•+ was determined to be 49,29 ± 5,97 %. The antimicrobial activity was verified by the agar well diffusion method. Two types of bacteria were selected for the determination – gram-positive Bacillus cereus, gram-negative Escherichia coli and yeast Candida glabrata. The results showed that the extracts have the highest antimicrobial activity against B. cereus. There were 64 volatile aromatic compounds identified in the extract, with monoterpenes and sesquiterpenes dominating. The obtained results confirm that P. amboinicus, or its prepared extract, has a good potential for use as a new and non-traditional flavor in various foods and delicacies, which can also increase their nutritional value.
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Analysis and characterization of beta-glucans from some natural sources
Vít, Radek ; Hudečková, Helena (referee) ; Márová, Ivana (advisor)
The aim of the bachelor thesis is to test and characterize commercially available products with declared -glucans content. The theoretical part describes -glucans, their possible sources, properties and utilization. Further, the theoretical part is focused on methods for determination of -glucan content. Saccharomyces cerevisiae yeast and oyster mushroom fungus are available as commercial sources of -glucans. Next individual groups of the active substances and principles of the methods used for their characterization are described too. In experimental part of this work the extracts from five commercially available sources of -glucans were prepared and characterized. Antioxidant activity, total polyphenols, proteins and carbohydrates were determined. For selected products, the content of vitamin C using HPLC and the lipid content using GC-FID were determine as well. An enzymatic method was used to determine the -glucan content. Two samples of the highest antioxidant activity were then subjected to antimicrobial and MTT tests.
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Analysis of active substances contained in lavender and thyme extracts
Vašíčková, Milada ; Vysoká, Marie (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis is focued on active substances contained in lavandula officinalis and common thyme extracts, mainly their possible antimicrobial and antioxidant effects. The theoretical part desrcibes chosen plants, compounds with antimicrobial and antioxidant effects, methods how to obtain and identify said compounds. In the experimental part, aquenous, ethanolic and oil extracts were prepared. Mentioned extracts were spectrophotometrically characterised for total content of polyphenols, total content of flavonoids and antioxidant activity. In conclusion possible applications of extracts in food industry instead of synthetic preservatives and their fotification were discussed.
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