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Encapsulation of natural antioxidants
Štindlová, Jitka ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
In theoretical part of this diploma thesis the basic properties of antioxidants, especially anthocyanins and phenolic compounds are described, as well as the basic features and principles of free radicals formation. The theoretical part also describes some possible ways of encapsulation of antioxidants into polysaccharide and lipid particles. In the experimental part basic characteristics of extracts from selected lyophilized fruits and vegetables (carrots, apples and mixed berries) are described. As group parameters of plant extracts the total antioxidant activity, content of flavonoids and phenolics, carotenoids, anthocyanins and ascorbic acid were determined. In experimental part also various encapsulation techniques were tested, encapsulation effectiveness of each technique was evaluated and the stability and size of the created particles were determined. As the best encapsulation method in terms of encapsulation efficiency in most of samples/parameters ethanol injection was found. On the other hand the particles prepared by ethanol injection are relatively unstable in terms of zeta potential, which is followed by their tendency to aggregate. As the most stable particles prepared by thin layer evaporation (TLE) and reverse phase thin layer evaporation (RP-TLE) were evaluated. Particles prepared by TLE, RP-TLE and chitosan-alginate particles exhibited a negative charge, while particles prepared by ethanol injection stayed uncharged and chitosan particles have a positive charge.
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Analysis of active substances in instant beverages for child´s nutrition
Jašková, Martina ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
The aim of presented diploma thesis was to characterize baby beverages for early infant feeding. Theoretical part deals with baby foods and beverages including breast milk. Practical part is focused on analysis of active substances in 21 commercially available fruit and herbal instant granular baby beverages and in 3 packaged tea bags for infant and toddler age. To evaluation of antioxidant properties some group parameters were used - total polyphenols, total flavonoids, total antioxidant activity and anthocyanins. All of them were analysed by using spectrophotometrical methods. For identification and quantification of individual phenolic substances was used RP-HPLC/UV-VIS and HPLC/PDA/LC-MS, identification of individual mono- and disaccharides was performed by HPLC/RI. L-ascorbic acid supplemented to some children's drinks was analysed by HPLC-NH2/UV. Protein analysis was performed by Experion microfluidic electrophoresis system (BioRad) and protein concentration was verified by colorimetric method. In general, the highest content of phenolic compounds was shown in tea bags when compared with instant granular beverages that contain mostly added simple carbohydrates. Using contact microbial tests proved immediately after opening and also during manipulation with tea boxes was verified that analysed baby teas are in agreement with strict hygiene requirements for baby beverages.
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Preparation of some application formula of antimicrobial substances
Krempaský, Kamil ; Němcová, Andrea (referee) ; Márová, Ivana (advisor)
The main aim of this study is to determine antimicrobial activity of herbal extracts and also encapsulate these extracts and lysozyme to liposomes. The extracts were prepared from above ground part of wormwood (Artemisia absinthium), aerial part of breckland thyme (Thymus serpyllum), the root of purple coneflower (Echinacea purpurea), liquorice (Glycyrrhiza glabra), corolla of pot marigold (Calendula officinalis) and berries of sea buckthorn (Hippophae rhamnoides). In all extracts antioxidant activity and the amount of total polyphenols and flavonoids was determined. All of these extracts and also lysozyme were used for encapsulation to liposomes. Prepared liposomes were then tested for their stability. Further, encapsulated as well as free extracts were tested for their antimicrobial activity on Escherichia coli, Serratia marcescens, Micrococcus luteus and Bacillus subtilis. Extract from Echinacea purpurea showed the highest antimicrobial activity.
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In vitro study of antioxidant activity of food supplements
Vopelková, Dominika ; Pořízka, Jaromír (referee) ; Omelka, Ladislav (advisor)
Bachelor thesis deals with the determination of antioxidant activity of food supplements in vitro. The theoretical part focuses on legislative requirements of food supplements, their characteristic and classification. Further, the attention is also devoted to antioxidants, their properties, effects, importance and utilization. Separate chapter describes herbs, which are an essential component of researched supplements, their effects and properties. For experimental part several food supplements in various forms (capsule, tea, juice, dried fruits) were chosen and total content of polyphenols was determined using the UV-VIS spectroscopy. Further, the total antioxidant activity is characterized by electron paramagnetic resonance involving DPPH method.
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Characterization of cereal products with fruit component for baby nutrition
Pražáková, Jana ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
Present bachelor thesis deals with the characterization of milk cereal products intended for baby food. The theoretical part focuses on the morphology of cereal grains, fortification, an overwiev of supplementary components used to fortification and their properties. For the practical part eight kinds of cereal dairy products of three different producers were chosen. In these products total polyphenols, total flavonoids, reducing and total saccharides and proteins were analyzed. The highest level of polyphenols was measured in product Sunar multicereal. The highest amount of flavonoids (more than 50 % of total phenolics) was found in Nestle fruit product. The highest level of total and reducing saccharides contained Nestlé honey flavour. High amount of proteins was found in products Sunar with multicereal flavour and pears with biscuits. Using HPLC/UV-VIS analysis vitamins C and E were determined. The highest content of vitamin C contained Nestlé with cookie lavor, while high vitamin E level was found in Sunar pear flavor and biscuits. Using HPLC/RI individual saccharides were examined. In all products high amount of lactose was found, mainly in the products of Sunar. Nestlé products contained mostly glukose, while in products Hami sucrose was detected as the most abundant saccharide.
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The nutritional importance of polyphenols in berries
MARTANOVÁ, Anna
People's nutrition is inseparable part of our lives. We could include substances, that we know are healtful, to our food. If we don't have enough of the substances, we can see negative effects on human organism. The substances are named micronutrients and vitamins. We could enrich a diet with substances that we think are healthy, but their deficit doesn't case pathological symptoms. Food which we put to this category is possible to name as function food. Function food contains substances which have positive effect on our health. One of the substances are polyphenols. This issue is very interesting for me, because polyphenols are compounds that are among others particulary found in berries, especially in blueberries. Blueberries are berries that are widespread throughout the world. One of the best sources of blueberries is also Sumava, where I come from and where blueberries are well connected. The first part of my thesis is about the functional foods and ingredients that make these foods Functional foods. Ordering: probiotics, prebiotics, synobiotiks, micronutrients, fytochemiks and polyphenols. Farther the first part deals with berries, specializing in blueberry and its properties and composition, which can have a positive impact on human health.In the second part there were two objectives of the work. The first aim of my study was to determine the diet, which includes foods that contain the optimum intake of polyphenols, equivalent to 120 ml of fetal native blueberries. Polyphenols are that part of blueberries, which make them so special. In the diet were preferentially embedded short dishes that have undergone heat treatment. Analyses of polyphenols in foods and beverages I got with the program GEOMED hospital Ceske Budejovice, Inc., Department of Clinical Pharmacology. Results polyphenol content were performed by HPLC. The content of polyphenols in native blueberries was laid as equal to 1 and the contents examined further product was then expressed as a multiple or ratio of the native blueberries. I take into account all these factors when drawing up the model menu. Another aim I have set is to map products in which the content of polyphenol is beneficial. There is a high number of products with blueberry flavour on the market. The content of blueberries, however, is often negligible. The surprising result was the polyphenol content in lemonade Toma, whose relative value ug / ml is 2.59 when compared with the native blueberry, which is placed as equal to 1. After the development work, in which I obtained information from the literature search, the sales network and the Department of Clinical Pharmacology, Hospital Ceske Budejovice, I would like to say that blueberries are an important source of polyphenols and that a diet which will include daily equivalent of receiving polyphenols, may not in any way differ from a regular rational diet. Not even cooking the dish precludes putting together this diet because blueberries are relatively stable against temperature changes. Inclusion of such a diet in the catering equipment could bring a positive impact in the future, especially for older people by improving memory function and balance.
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Fytochemical potencial of polyfenols contain in berries
KRUMPHANZLOVÁ, Iva
This thesis sums up findings on polyphenols and their positive influence on human health. In these fytochemicals, unlike in micronutrients, recommended daily amount cannot be estimated. Micronutrient deficiency in food can cause deficiency symptoms, while in polyphenol deficiency, the deficiency does not occur. When they are present in sufficient amount in food, it is considered functional food, which is important for civilization illnesses prevention. At the beginning of the theoretical part, the polyphenol classification from pharmacological and chemical point of view is represented. On the basis of this classification important role of antioxidants and flavonoids is described. Special attention is being paid to resveratrol, which is populardue to its well known "French paradox". The following part considers the polyphenol influence on human health. The way in which polyphenols protect our body from certain diseases is explained in detail. Most of the health benefits are supported by studies conducted on animals. These studies are also mentioned and described in this paper. In the theoretical part the process of absorption and the polyphenols safety for human body is also explained. Polyphenol sources are listed in the last subchapter. The work is mainly aimed at blueberry fruits (Vaccinium myrtillus) and vine grapes (Vitis vinifera). Other berries are briefly mentioned as well, such as cranberries, raspberries, blackberries and currant. The goal of this work is to create a diet that would provide a functional daily amount of polyphenols. This amount can be compared to 120 ml of native blueberries. Only products, consumable without cooking, are used in this diet. The second goal is to chart, which food products are adequate source of polyphenols. On the basis of these goals, research inquiries were defined. Research inquiry No. 1: What amount of polyphenols is contained in berries, especially blueberries. Research inquiry No. 2: Which food products (without cooking) are ideal to be included in diet, to provide adequate daily amount of polyphenols. To asses polyphenol content in blueberries, analysis of polyphenol content acquired through GEOMED program from Nemocnice České Budějovice a.s., department of clinical pharmacology, was used. Assessments were made using the HPLC method (high performance liquid chromatography) in cooperation with the biological centre AV ČR in České Budějovice. Thanks to this analysis, the first inquiry can be answered. An interesting phenomenon is discovered, that frozen blueberries have higher polyphenol content then cooled ones. Malvidin (malvidin-3-6"-acetoyl glycoside) was chosen as priority anthocyan since it is most represented in the blueberry. Remaining information about polyphenol content in certain food products were drawn on Joseph Maroon´s book, MD, FACS (2010). The practical part involves a diet for 14 days, which meets the given requirements. The results clearly show that it is possible to create a diet rich in polyphenols. A list of blueberry products accessible to everyone is included. Blueberry dairy products, jams, beverages, fruit salads and fruit pyre have been analysed. The list shows which product contains the most polyphenols. The required amount can be achieved by the proper combination of given products. The ideal one proved to be 200 ml of red wine and one blueberry dairy product (with the malvidin value higher than 64). Findings in this paper will serve to promote polyphenol awareness and itseffects. This diet can be used in nursing homes, where their positive influence on equilibrium can be applied. It can also be used in spas and other alimentation related facilities.
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The Methods for the Detection of Antioxidant Substances
TURKOVÁ, Kateřina
Antioxidants and free radicals are widely discussed in the clinical and nutritional literature. Various reactive oxygen species (ROS) may be produced from normal biochemical, essential metabolic processes or from external sources as exposure to a variety of agents presented in the environment. Lipids, proteins, carbohydrates and DNA are all capable of reacting with ROS and can be implicated in etiology of various human disorders. The antioxidant system protects the organism from the effects of free radicals by scavenging them and thus preventing structural damage of cells. Measuring the individual components of the antioxidant system has provided important information about the defences against free radical effect. During the last decade, many analytical methods have been developed to determine the antioxidant activity of natural compounds and their mixtures in vitro. Some procedures involve the methods based on the generation of various radical species and their elimination by treatment with potential antioxidant compounds. The tests used for the evalution of total antioxidant activity are: Trolox equivalent antioxidant capacity-TEAC, diphenylpicrylhydrazil - DPPH, oxygen radical absorbance capacity-ORAC and the methods testing the ability to prevent lipid peroxidation. The other group includes the procedures that are based on measurement of redox properties of compouds (ferric reducing antioxidant potential assay-FRAP, cyclic voltammetry, HPLC).
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Sources and methods of saturation of the organism with antioxidants
NOVOTNÁ, Nikola
The aim of the thesis is to characterize sources of antioxidants and inquire the depth of knowledge about antioxidants among students of secondary school. The theoretical part of the thesis describes and divides important antioxidants for human health. The main sources of antioxidants in human diet are there divided, described and compared as well. The practical part of the thesis includes the inquiry which evaluates the theoretical interest in antioxidants and dietary intake of antioxidant supplements among 17-19 years-old secondary school students. The results are analyzed and graphically displayed. Research shows that more than a half of the respondents know the term antioxidants and consume these substances in the diet. However, it is important to increase knowledge of antioxidants already among young people and ensure the intake of these essential substances from a varied diet.
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Antioxidants in Food and Their Function in the Process of Defence Against the Free Radicals Effects
MOUDRÁ, Táňa
The thesis deals with antioxidants in food and their function in the process of defence against the effects of free radicals. At first, antioxidants are defined and their clasification is described in the theoretical part. Then this part deals with antioxidants in food, their effects on people´s health and antioxidants recommended daily doses. Possitive and negative effects of free radicals on people´s health and their relation to antioxidants are mentioned next. In the practical part, I concentrate on the survey focused on the investigation of the population awareness of antioxidants and their effects on health. One hundred and sixty respondents took part in the survey. They were devided into two groups; working people and pensioners. The questionnaire contained twelve questions which investigated the population awareness of the topic. The data collection took place in January 2013 and it was evaluated in February 2013. The collected data were evaluated according to basic statistical methods. The ascertained answers were put into unified tables and then they were compared. Especially, the general awareness was investigated and then the effect of education on the knoledge of the topic was considered.
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