|
|
Assessment of chosen aroma compounds in foods
Greifenthalová, Ivana ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This diploma thesis is focused on the problematic of assessment of 26 most important allergenic aroma compounds in foods, flavoured herbal teas were chosen as the model samples. Aroma is the one of the main characteristics of tea, which is closely linked to taste and odour. The theoretical part of this work is focused on the characteristics of tea, tea types, producing technology, classification according to the fermentation and also their undeniable impact on the human organism. In the experimental part, the allergenic aroma compounds in 10 chosen samples of flavoured tea were identified and quantified using the solid phase microextraction (SPME-GC-FID) in conjunction with gas chromatography. The work also includes sensory evaluation of taste and smell of tea samples by qualified assessors.
|
|
| |
|
|
Nanoparticles preparation by green synthesis
Kortusová, Dominika ; Valušová,, Eva (referee) ; Šimšíková, Michaela (advisor)
This thesis deals with green synthesis of noble metals nanoparticles. The first part contains secondary literature research which maps both the traditional and newly developed techniques of nanoparticles preparation. Most attention is given to the various types of green synthesis, which constitute an environmentally friendly alternative to industrially applied methods. The second part deals with the preparation of noble metal nanoparticles using tea broths. The section describes the entire synthesis process and includes photographic documentation. A total of eight colloidal solutions were prepared, four of each metal. The nanoparticles were subsequently analyzed using UV-vis spectroscopy. A time-lapse spectroscopic description of each synthesis was also undertaken. Furthermore, the size distribution of the particles by volume was measured and compared with the pictures obtained by scanning electron microscopy. The results have showed that tea broths, especially those from black tea and rooibos, are suitable for the biosynthesis of stable noble metal nanoparticles.
|
|
| |
|
|
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.
|
|
|
Measurement of corrosion resistance of anodized aluminum protective surface layers
Redr, Martin ; Jandová, Kristýna (referee) ; Chladil, Ladislav (advisor)
This master’s thesis is focused on anodic oxidation of an aluminium surface with subsequent sealing of the surface using mid-temperature sealing methods. The research in the theoretical part of the thesis is carried out in surface treatments of aluminium and its alloys, where attention is mainly paid to anodic oxidation, as it is the most widely used surface treatment. The second discussed and at the same time key topic is the sealing process of the anodic coating, which has a fundamental effect on the quality of the corrosion resistance of the resulting surface. In the practical part of the thesis, a number of anodic oxidation experiments with subsequent sealing of the coating on prepared aluminium samples and their subsequent evaluation according to ČSN EN ISO 3210 standard were carried out. Mid-temperature sealing experiments were mainly focused on the use of triethanolamine (TEA), which seems very promising in terms of the resulting sealing quality.
|
|
|
Antimicrobial activity of rosehip teas
Ďubašáková, Mária ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The aim of this bachelor theses was to determine the concentration of biologically active substances such as polyphenols and flavonoids and also total antioxidant activity of tea extract of rosehip and also research antimicrobial activity and the effective concentration of the extracts against selected bacteria. Theoretical part is focuses on the description of natural antioxidants and active effect against free radicals, description and distribution of tea, botanical and chemical description od rosehip and basic information about bacteria. There is section describe selected methods for the determination of polyphenols, flavonoids, total antioxidant activity of these extracts, and verification of antimicrobial activity against grampositive and gramnegative bacteria in experimental section. From the results is flow, that the analyzed extracts have no inhibition activity against bacteria. Also was found that aqueous extracts has high proportion flavonoids and polyphenols.
|
|
|
Detached house with tea premise
Rydlo, Jan ; Papranec, Michal (referee) ; Petříček, Tomáš (advisor)
This thesis describes the design of the house with a teahouse establishment. The house is situated on a basement and two floors. In the basement on the left side, there is a part for commerce with a store, warehouse and an office for e-shop management. In the right part of the house there is a garage and a gym. In the aboveground floors there are just residential parts of the building, which are in a very spacious and luxurious. The rooms are large with a high ceiling and large French windows in almost every room. Exposed rafters in the living room and kitchen combined with high ceilings creates a feeling of nobleness and freedom. The building is made from lost formwork in the underground part and from brick blocks Porotherm in the aboveground part. The shed type roof is divided into two parts, sloped away from the center of the house. The whole building is very well thermally insulated with insulating material over the entire façade and over the supporting elements of the roof. Also the large parcel the building stands on is a dominant element. In the exterior, there will be built a large ornamental garden in the backyard, and usable area for growing crops in the rear part of the property. Large pond and gazebo will be beneficial for the residents of the building.
|
|
|
Content of selected alkaloids in tea and coffee
Trenzová, Kristina ; Divišová,, Radka (referee) ; Diviš, Pavel (advisor)
This master thesis deals with content of selected alkaloids in tea and coffee samples. Theoretical part of this paper focuses on basic characteristic of Camellia sinensis and Coffea arabica/canephora, its processing technology and chemical composition. Furthermore, there is discussion about effects of methylxanthines on the human body, the effects on health and metabolism in plants capable of accumulating methylxanthines. The samples were extracted into an organic solvent and also prepared in the aqueous phase according to the recommended preparation. This thesis focuses on xanthine alkaloids - caffeine, theobromine and theophylline. Of the coffees, Robusta coffee from India had the highest caffeine concentration (1730 mg/l), which corresponds to 1,72 % in coffee. From Arabica samples, the highest caffeine concentration was measured for Honduras coffee (1115 mg/l), which is 1,11 %. The highest values of tea samples were measured for Ceylon types, the highest caffeine concentration was measured for black Ceylon 2087 mg/l, which is 2,08 %. The highest concentration of theobromine was in Ceylon gunpowder (175,4 mg/l). Alkaloids passed into aqueous solutions with almost 100 % efficiency, depending on temperature and time. The best penetration was for coffees prepared by a mocha teapot and for pu-erh teas. The worst for green teas and maté samples.
|
|
|
Study of properties and effect of some natural antimicrobial substances
Horňáková, Nikola ; Kostovová, Iveta (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the testing of natural antimicrobial substances of plant origin, dealing with their characterisation, their effect against the microorganisms, optimization of antimicrobial testing and increasing of efficiency of their active compounds. Theoretical part of this thesis describes a characterisation of used natural species, their important properties, spectrophotometrical methods applied in determination of active compounds, opportunities of stabilization of natural substances and various techniques of antimicrobial testing. In experimental part 8 kinds of tea and non-tea plants (Pai Mu Tan, Formosa Gunpowder, Gunpowder Black, Honeybush, Lapacho, Aspalathus linearis and Paullinia cupana) were used and combined with 6 herbal species (Syzygium aromaticum, Urtica dioica, Hippophae rhamnoides, Matricaria recutita, Plantago lanceolata and cinnamon), extracted by different solvents (water, ethanol and dimethyl sulfoxide). In these extracts amount of antioxidants and effect to three bacterial cultures (Escherichia coli, Micrococcus luteus and Serratia marcescens) were determined. To improve antimicrobial, antioxidant activity and stability aqueous tea extracts were encapsulated into liposomal particles.
|
guest ::
