|
|
Study of the presence of phenolic substances and their antioxidant activity in food products containing rosehip (Rosa canina L.)
Hronová, Vendula ; Mikulíková, Renata (referee) ; Kovalčík, Adriána (advisor)
This bachelor's thesis monitored the content of bioactive substances and antioxidant activity in the jams made of the fruit of rose hips (Rosa canina L.). The jams were sweetened with various sweeteners such as cane sugar, beet sugar, erythritol and stevia. Moreover, the rheological properties of jams were determined. The properties of home-made jams prepared from rosehip fruit were compared with the commercial jam. Another aim was to determine whether the by-products received after the production of jams could serve as beneficial sources of bioactive substances after the preparation of water extracts. The content of carbohydrates, polyphenols, flavonoids, and antioxidant activity were determined in jams and extracts spectrophotometrically. Next, the spectrophotometric detection of pectin, the chemical characterization of jams by infrared spectrometry, and the spectrophotometric determination of the jam colour were performed. The concentration of bioactive substances in jams was influenced by the geographical location and the time and weather conditions of harvest. The rheological properties and pectin content of the jams depended on the type of the used sweetener. The assessment of the water extracts prepared from the by-products after jam production and from the dried fruits of rosehip showed the high content of bioactive substances and high antioxidant activity in all tested extracts. The presented work points out that it is possible to prepare jams with superfood properties from the fruit of rose hips and extracts with high antioxidant activity.
|
|
|
Characterization of blackthorn products
Červinková, Zuzana ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
This bachelor thesis deals with the preparation and the chemical characterization of ethanolic extracts and products from the blackthorn (Prunus spinosa L.) fruit. The theoretical part of the work contains the characterization of the blackthorn and describes the chemical composition of the fruit. Furthermore, the theoretical part states possible effects and possible uses of the Prunus spinosa L. fruit in the food industry, folk medicine and pharmacy. The experimental part describes the preparation of the extracts (40% ethanol) and the products (i.e., homemade sloe wine and homemade blackthorn liqueur). The content of reducing sugars, polyphenols and flavonoids was quantified in samples of wine, liqueur, juice and ethanol extracts. Furthermore, the antioxidant activity of individual samples was determined. Two spectrophotometric methods for the determination of reducing sugars were used and compared, namely the Somogyi-Nelson (SN) assay and the 3,5-dinitrosalicylic acid (DNS) assay. The DNS assay provided slightly overestimated results, while the results from the SN assay were closer to the actual content of reducing sugars. Polyphenols and flavonoids are substances that have antioxidant properties. A strong correlation was observed between antioxidant activity and the concentration of flavonoids.
|
|
|
Biochemistry of polyphenols effects in the treatment of vascular disease
Kondrashov, Alexey ; Štípek, Stanislav (advisor) ; Pecháňová, Olga (referee) ; Matouš-Malbohan, Ivan (referee)
This Ph.D. thesis deals with the deep analysis of polyphenols effects toward vascular disorders. This work provides a number of experimental results of studying both the effects of natural bioactive compounds in red wines and potatoes, and their application to the experiments which includes experimental animal models with spontaneous hypertension. Methods and equipment used in experimental studies allowed us to make several new statements regarding the universal nature of the relationships between the antioxidant capacity and the polyphenolic content in examined foodstuffs. Besides this it is also recognized that food is a source of minerals which also contribute to the total antioxidant capacity and therefore may have influence the endogenous antioxidant enzyme system by providing the essential cofactors. Experimentally we have found that the concentrations of magnesium known for its therapeutic action in wine and red wine extract are comparable to the mineral waters recommended for the treatment and prevention of cardiovascular and metabolic diseases. Moreover, synergistic interactions between selected minerals have been found. The key issue of bioavailability of polyphenols for supporting the idea of the beneficial effects of diet rich in fruits and vegetables toward vascular disease prevention...
|
|
|
Study of geographical authenticity of Moravian white wines
Horáková, Kristýna ; Křikala, Jakub (referee) ; Diviš, Pavel (advisor)
The aim of this bachelor thesis was to verify geographical autenticity of Moravian white wines based on elemental analysis. This data were completed with the analysis of organic acids, fenolic compounds and atioxidants in wines. There were used two spektrometric methods for the elemental analysis (ICP-MS and ICP-OES). The concentration of organic acids was mesured by Ion chromatography. To determine the concentration of phenolic compounds in wines there was used the high performance liquid chromatography (HPLC-DAD), the content of antioxidants and the total content of phenols was measured on spectrophotometer. In total there were 33 samples of wine from 4 Moravian subregions. For the purpose of determination the samples in groups the dataset was firstly corrected by Grubbs test for remote results. From those data the box plots were created which represents the minimal, maximal and mean concentrations of each measured component. Furthermore the analysis of variance was applied, which picked up 12 statisticly valuable parameters from the whole 47. By appliyng the multidimensional statistical methods (Pearson correlation analysis (PCA) and discriminant analysis (DA)) were compiled mathematical models for the division of Moravian wines according to geographical origin. The success rate of the discrimination test was 96,97%. The cross-validation test showed an 81,82% success rate for classifying unknown samples.
|
|
|
Plant-based cosmetic products
Horváthová, Iveta ; Pavelková, Renata (referee) ; Skoumalová, Petra (advisor)
The aim of this bachelor thesis was studying an antimicrobial activity of selected herbal extracts and their encapsulated forms as liposomes. Furthemore, the thesis focuses on determonation of biologically active compounds, natural pigments and antioxidant activity. 6 kinds of herbs were studied - Humulus lupulus, Matricaria chamomilla, Taraxum officinale, Bellis Perennis, Cymbopogon citratus and Rubus Fruticosus. In teoretical part, the general characteristics of herbs and their use are described, it also includes the description of active compounds, microorganisms and used methods. Practical part is focused on characterisation of herbs from the perspective of antioxidant activity, determination of totaly phenolic content and flavonoids, chlorophyll and carotenoids. For analysis of antioxidant activity, concentration of phenolic compounds and flavonoids and antimicrobial activity aqueous and 20% ethanol extracts were prepared. Based on the obtained results, selected extracts were encapsulated into various types of liposomes consisting egg yolk, soy or sunflower lecithin. Generally, ethanol extracts showed higher content of active compounds. For chlorophyll and total carotenoid content determination the highest content of natural pigments was found in Taraxum officinale. Furthemore, antimicrobial activity of extracts and liposomes against 6 strains were determined - Micrococcus luteus, Serratia marcescens, Escherichia coli, Propionibacterium acnes, Staphylococcus epidermidis and Candida glabrata. The highest inhibitory effect was found in Matricaria chamomilla and Cymbopogon citratus samples. Encapsulation effectivity, size, stability and long-term stability of liposomes after a week and two months were determined. From the perspective of zeta potential all the particles were stable and reached a good encapsulation effectivity. It turned out that after two monts of storage the particles decomposed and active compounds into surroundings were released. Selected herbs generally had high content of antioxidants and active compouds. The most suitable lecithin for encapsulation was shown to be sunflower lecithin.
|
|
|
Isolation and characterizaation of oil from some types of coffee
Vašků, Barbora ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
Coffee, extract, oil, phenolic compounds, flavonoids, antioxidant capacity, SPF, critical wavelenght.
|
|
|
Optimization of echinacea drops production technology
Boberová, Jana ; Vespalcová, Milena (referee) ; Zemanová, Jana (advisor)
This diploma thesis deals with the production of herbal drops from Echinacea and the determination of the content of selected active substances. In the theoretical part, the taxonomic classification of echinacea, its botanical characteristics and growing conditions are mentioned. The history of cultivation and uses of this plant are also mentioned. An important chapter of the theoretical part is the chemical composition of the plant and differences in composition between individual cultivars of Echinacea. Methods for obtaining active substances and their determination are also mentioned. The last chapter is devoted to the technology of production of echinacea drops. In the experimental part, the extraction was optimized for dried flowers and roots of E. purpurea. The following extraction system was determined for the flowers: 40% ethanol, time 6 hours, weight to solvent ratio 1:10 and room temperature. For the roots, 20% ethanol and a time of 24 hours, a ratio of 1:10 and room temperature were evaluated as the best conditions. Furthermore, the best extracts were prepared, in which the content of total phenolic substances was set at 0.799-0.839 mg/ml, then the antioxidant activity was determined in the range from 116 to 242 µg T/ml, and finally the analysis of aromatic substances was performed by HS-SPME-GC-MS. Two commercial samples were also tested to compare the prepared extracts.
|
|
|
Vliv řízené mikrooxidace na technologii bílých vín =: The effect of controlled micro-oxygenation on technology of white wines /
Průšová, Božena
The PhD.-dissertation thesis deals with the effect of microoxidation on white wine technology. The varieties ‚Pinot Blanc‘ and ‚Pinot Gris‘ were used for the experiment in 2016 and 2017. Micro-oxygenation was applied in the first third of the fermentation process and during the maturation of wine. The effect of microoxidation on the course of fermentation was monitored. In micro-oxygenated wines, a statistically significant increase in the number of living yeast was observed immediately after the micro-oxygenation treatment, compared to the control experiment. The increase in cell mass was also observed by measuring the consumption of ammoniacal nitrogen and nitrogen contained in the amino acids. The results of the experiment show a higher consumption of ammonia nitrogen in the micro-oxygenated wine. The amino acid content did not change significantly. During the whole fermentation process, the course of antioxidant activity was monitored. There were no statistically significant differences between micro-oxygenated wines and control, in some cases the antioxidant activity of micro-oxygenated wines was significantly higher. This phenomenon can be explained by the formation of new phenolic compounds, such as gallic acid, which in some cases has been confirmed by HPLC results and theoretically higher production of yeast cell wall breakdown intermediates, which are potent antioxidants. An aromatic profile was determined in the resulting wine by GC analysis and sensory evaluation. Results from GC analysis show higher concentrations of higher alcohols and esters. The results of this experiment from the year 2016 have been successfully published in the reviewed periodical Ciencia e Técnica Vitivinícola: Bozena Prusova, Mojmir Baron, Effect of controlled micro-oxygenation on white wine, Ciencia Téc. Vitiv. 33 (1) 78-89 (2018), DOI: 10.1051/ctv/20183301078.
|
|
|
Studium antimikrobiálního efektu hroznových semen
Koláčková, Ivana
This paper is dedicated to gathering information about utilization of Vitis vinifera L. extracts, mainly grape seed extract (GSE), production of GSE in two variants (aqueous or methanol GSE) and description of its characteristics. Extract was rich in polyphenols (13462 mg/l GAE), measured by Folin-Ciocaltel method. Also 3615 mg/l GAE of flavonols was present in GSE. Antioxidant activity measured by DPPH method was high, 7978 mg/l GAE. Disc diffusion method was used for antimicrobial activity analysis. GSE's effect was tested on five common microorganisms. Results of the experiment show that GSE strongly inhibits growth of Bacillus cereus, Candida tropicalis and Enterococcus faecalis. However, it was not effective against Escherichia coli and Pseudomonas aeruginosa.
|
|
|
Obsahové látky planých rostlin používaných jako zelené koření
Doležalová, Vanda
This bachelors thesis presents the characteristics of wild plants used as green spices, their content substances and antioxidant activity. The thesis describes 11 wild plant species, their original natural habitat and their current common occurrence, botanical description, content substances, gathering conditions and the possibilities for their use. Furthermore, the thesis describes content substances (metabolites, minerals and vitamins), their concentration in different species, their effects and functions in the organism, antioxidants and free radicals, including their descriptions, functions and the influence on organism and the method of their assessment.
|
guest ::
