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Toxic compounds in a diet as a factor of chronic diseases
Logerová, Hana ; Dlouhý, Pavel (advisor) ; Černá, Milena (referee) ; Kouřimská, Lenka (referee)
Flame retardants have been used in the Czech Republic since the 1980s and 1990s as a part of the polymer matrix of plastic materials to decrease their combustibility and thus the risk of fire. Brominated flame retardants (BFR) are commonly used, polybrominated diphenyl ethers (PBDEs) are the most abundant flame retardants in plastic materials. The human population is exposed to these compounds particularly via diet containing fatty fish, meat and dairy products and via inhalation of dust particles. Another aspect is the duration of the exposure: it is known that human beings can be exposed to BFRs from infancy through prolonged breast feeding because breast milk can be contaminated by these compounds. This study was performed to investigate the concentrations of the main representatives of BFRs occurring in human adipose tissue and to compare these values with the concentration of chlorinated contaminants (PCBs, DDTs). The pollutants levels were newly measured in solid adipose tissue removed during surgery. A total of 107 samples of fat were taken from 19 - 76 year-old volunteers mostly obese women. A total of 16 PBDEs congeners were determined, of which only six occur in more than 38 % of fat tissue samples. The total PBDEs level attained an average value of 3.31 ng/g, which is 25 % less than was...
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Nutritional analysis and optimization of breeding of selected species of edible insects under conditions of the Czech Republic with regard to human health
Adámková, Anna ; Kouřimská, Lenka (advisor)
All over the world, the edible insects are considered a highly nutritious food with high protein and fat content. However, the nutritional value of insect is not constant. It can be affected by species, developmental stage, rearing technology or nutrition.
Therefore, this thesis was aimed at obtaining the selected nutritional value of edible insects. Analyses were focused on the determination of the crude protein content, fat content, fatty acid profile and sterols in selected species of edible insects, which can be commonly reared in the Czech Republic. At the same time we also analysed samples of insects reared on the island of Sumatra to evaluate the influence of the climate on the nutritional value. The main aim of the thesis was the determination of optimal breeding conditions, developmental stages and feed rations for obtaining good production of insects with nutritional properties suitable for human nutrition. The analyses showed a high nutritional value of selected insect species, but also confirmed the significant differences in the content of individual nutrients between different species depending on the climate conditions and developmental stage. Comparing the fat and crude protein content in edible insects and other conventional sources of meat it has been found, that the examined insect is similar to beef concerning the fat and crude protein content. The results obtained are the basis for determining the appropriate rearing conditions and developmental stages for obtaining insect with the desired nutritional properties for human nutrition.
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Glycaemic index of food and its determination
Špiláčková, Aneta ; Kouřimská, Lenka (advisor) ; Monika, Monika (referee)
The purpose of this thesis was to elaborate a literature recherche on a given theme with focus on analytical methods to estimate the glycaemic index of food.
This bachelor thesis is divided into three main chapters. First chapter describes general characteristics of glycaemic index of foods and influencing factors. In this chapter states the influence of high and low glycaemic index foods on health, wellbeing and glycaemia in humans. Subsequent part of this chapter is dealing with many other factors that influence the absolute amount of glucose in blood in 2 hour interval after meal.
Chapter two initiates into conventional and continual methods of glycaemia measurement.It highlights the advantages and limitations of each of these methods.
Third, the most extensive chapter is dealing with methods of glycaemic index assessment. This chapter is broken down into two parts. First part specifies clinical methods that are also called in vivo, and the second part is focusing on in vitro methods. Clinical methods require blood glycaemia measurement in healthy volunteers after consuming a test meal. With this method we are able to reliably state the glycaemic index of certain foods.
The limiting factor of this method is that it is rather time-consuming and it requires higher financial means. These measurements take place under a strict control, according to guidelines and only with the approval of ethical committee.
Analytical methods are based on simulation of human digestion. In vitro methods use hydrolysis index to obtain the glycaemic index. The final values are only an assessment of glycaemic index of given food. Other method that is described is measurement of fast and slowly available glucose and starch in given test foods. It is based on measurement of released glucose from the test food with HPLC method, time incubation and standardized conditions. Last method includes partitioning of a test food, and subsequent HPLC analysis of carbohydrates and sugar alcohols. The HPLC results are processed in artificial neural network to reveal glycaemic index values.
The advantages and disadvantages of each mentioned method are stated in conclusion of this work. I compared and contrasted reliability, elaborateness, budget demands
of analytical methods with clinical assessment methods.
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Comparison of nutritional values of different edible insect species
Maňhal, Daniel ; Kouřimská, Lenka (advisor) ; Kulma, Martin (referee)
The worlds limited agricultural resources will soon no longer be able to continue to support its ever growing population. One way to alleviate this problem is to integrate insects into the human diet, which is an increasingly common practice in Asia, Africa and South America. This practice has proven to be beneficial in a number of ways. Insects have better feed-conversion efficiency, transforming organic matter into larger amount of edible body mass than traditional livestock. Comparing to the livestock, insects have much smaller ecological impact on the environment. On the other hand, allergic reactions to toxins produced by some insects represent a potential risk of entomophagy. Nutritional values of insects depend on many factors, such as type of insect, its developmental stage, sex, and consumed feed. Generally, insects are a rich source of nutrients comparable to or even higher than traditional sources of meat.
Nutritional values of farm raised field crickets (Gryllus assimilis), originating from the Czech Republic, were analyzed in the experimental section of this thesis. Specifically, contents of dry matter, crude protein, fat and fatty acid profile were the main focus. The dry matter content was determined using an infrared technique. The crude protein content was measured using the Kjeldahl method. The Soxhlet method was applied for fat extraction. Extracted fat was determined gravimetric. Using gas chromatography, a lipid profile was obtained. Measured values were compared to those found in the literature. Emphasis was put on the comparison with other types of potentially edible insects and on the nutritional values of wild and farmed insects. Finally, these nutritional values were compared to the corresponding nutritional values of conventional meat to illustrate the benefits of entomophagy.
The analyzes showed that insect originating from the Czech Republic had very similar qualitative composition to species from different geographical regions and its nutritional value is fully competitive with conventional meat.
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Evaluation of selected qualitative parameters of apples produced under different growing methods
Dresslerová, Ivona ; Kouřimská, Lenka (advisor) ; Jan, Jan (referee)
The most spread system of agricultural production is conventional system, which reaches the best profits by its excessive inputs into production such as fertilization, chemical spraying, heavy engineering. However the importance of ecological (BIO) and integrated (I.P.) production has been increasing among the consumers recently. Mainly because of environmental sustainability and protection of their own health. The aim of this study is to compare qualitative characteristics of 10 different apple cultivars (Melodie, Šampion, Gloster, Idared, Angold, Topaz, Goldstar, Ontario, Florina, and Rubín) with reference to the type of production system. The dry matter content, amount, concentration of carbohydrates, ascorbic acid, sensory evaluation and overall profile of volatile compounds were analysed in apples coming from both ecological and integrated agriculture.
The dry matter content of all apple cultivars was measured by using two different methods. At the same time drying in an infra-red scale and refract metrical measuring by a portable refractometer were carried out. Concentrations of different carbohydrates (sucrose, glucose and fructose) were analysed by HPLC method with RI detection. The content of ascorbic acid (AA) was determined by HPLC with UV/VIS detection. During the sensory evaluations a protocol for a trained sensory panel was created including profile, pair and pair preference test. With an aim of detection of volatile aromatic compounds´ profile there was a sorption prepared on SPME extraction with following analysis on GC-GC-MS.
In the concentration of C vitamin was the cultivar found statistically significant (p = 0,0004) and not in the supposed type of production. The final concentration of ascorbic acid was 13-130 mg/kg in BIO apples and 10-103 mg/kg in apples from integrated production. Overall 7 BIO cultivars had higher content of AA in comparison to I.P. The highest concentration of AA was in cultivar Ontario. In total 7 BIO cultivars from 10 had bigger content of AA in addition to integrated samples. The most present carbohydrate in apples is fructose in which was found a statistically significant difference between values of BIO and I.P. (p = 0,0272). The highest figure of fructose and also of sum of sugars was Angold BIO (422,3 g/kg). The highest presence of dry matter was found in cultivar Florina BIO (18,62 %). Refract metrical matter was in the range from 11 to 17 Brix.
There was a statistically significant importance proved between the figures of BIO and I.P between both dry matters. At the same time it was proved that there is present a dependence between them based on correlation coefficient (r = 0,9622). It was assumed that the overall sum would correlate with refract metrical dry matter, but this was not confirmed. There was also proved a statistical difference (p = 0,0002) between the BIO and I.P apple weights. In all cases of samples the weights of I.P apples was higher. In sensory analysis the cultivar Šampion BIO was evaluated the best from the overall intensity and pleasure of the taste.
Topaz I.P was evaluated as the sample with the most pleasant taste and Florina I.P with the highest taste intensity. By the analysis of pair preference test results it was confirmed that there is a statistically significant difference on the selected level of probability 99%. But preference in any of production systems was not confirmed. During the analysis of overall profile of volatile aromatic substances it was found out that the same cultivar of different production has the same composition, but different relative concentration of the present substances.
This problematics needs further and more detailed analysis, which would prove or disprove influence of the cultivar on all analysed aspects.
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Comparison of the nutritional quality of school meals
Plisková, Gabriela ; Kouřimská, Lenka (advisor) ; Diana, Diana (referee)
School lunches are a part of a day for almost every child, therefore it is important to serve nutritionally balanced meals in canteen and to supply children with nutrients. School canteens are important educational resources, providing a model that guides student food choices and composition of their meal could be a possible mechanism for child obesity prevention, what has become a phenomenon of these days. According to the regulation of the Ministry of Education, Youth and Sports no. 107/2005 Coll. a school lunch should provide 35% of the daily income of energy.
In this work were evaluated lunches of two Czech elementary schools in period of 10 days. The nutritional value of meals was evaluated by lists of used food processing and subsequent their comparison with recommended doses in the Nutriservis program.
The results of comparing with recommended values were similar for both schools. Lunches at both schools exceeded the recommended daily dose prescribed for protein, sodium, potassium and vitamin C. Contrary calcium had not reached the recommended daily dose anytime.
We can´t conclusively say, that the school served meals were unsuitable, because the meal consumed during the rest of the day is not included.
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Sensory evaluation of wafers by consumer test
Kaňka, Martin ; Kouřimská, Lenka (advisor) ; Zdeňka, Zdeňka (referee)
This thesis deals with a consumer test, which was conducted with a questionnaire survey. For research four kinds of Austrian Manner wafers were used Neapolitaner, Vollkorn, Vanilla, Zitrone. The thesis is focused on the difference between the expected and perceived impressions of all flavored wafers. It further compares the result of research carried in Austria and Vietnam. The questionnaire was presented to 123 respondents. The distribution of the number of men and women was similar as in Austria and in Vietnam.
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Effect of composition on sensory quality of selected thermally processed meat products
Nováková, Lucie ; Kouřimská, Lenka (advisor) ; Miroslav, Miroslav (referee)
The theoretical part of this thesis deals with the characterization of two representatives of the heat-treated meat products a traditional czech sausages called špekáčky and Gotha salamis, their composition, manufacturing technology, history and present legislative directives related to manufacture. A substantial part is the introduction to the field of sensory analysis methods and approach, which are used to determine sensory quality of špekáčky and Gotha salamis.
The experimental part is based on the assumption that between products from different production levels, particularly farm and commercial, are statistically significant differences in the quality perceived by consumers, in the event that these products have significantly different recipe. The evaluated parameters were (in the case of both products) appearance of the cut, preparation, color, aroma, consistency, taste, saltiness and overall impression. The evaluators recorded results to the unstructured graphical scales of length 100 mm. Each descriptor has a label with the requirements of Decree no. 264/2003 Coll. as amended.
One representative farm production and one commercial production of each product type was rated. In case of špekáčky statistically significant difference demonstrated only for descriptors flavor and overall impression, which amounted to a farm product of inferior quality, was demonstrated. This small difference is caused in a very similar composition of both samples. For Gotha salamis statistically significant difference has been shown in most of the descriptors. The overall impression, color and smell of a farm product was better than the product of commercial production, in the design and appearance of the cut was a commercial product better than a farm. These differences are caused by totally different composition (in favor of the farmer's product) and different pushing the technology used (in favor of commercial product).
Given hypothesis was confirmed - using a different recipe has an effect on the sensory quality perceived by consumers. But the fact of farm production does not guarantee a higher quality compared to the commercial product. It is always necessary to monitor the composition of the product.
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Organoleptic characteristics of the venison and venison products
Henrychová, Marie ; Kouřimská, Lenka (advisor) ; Daniel, Daniel (referee)
This thesis is focused on the organoleptic properties of game and farm animals meat. Some attention is dedicated to the game meat products too. Hypotesis Organoleptic properties of game meat are statistically different from meat of farm animals was evaluated. Comparison of the scientific publications concering this topic was made. Organoleptic properties are dependent on physical and chemical attributes, thus some of these important attributes are discussed in this thesis.
Results of this thesis show, that there are significant differences between organoleptic properties of game and farm animals meat and the hypotesis is valid. Within chemical and physical properties of compared kinds of meat there are significant difference especially in fat content and fatty acids profile. Game species presented in this thesis have lower fat content and also more favourable fatty acids profile and especially content of unsaturated fatty acid is higher. Significant differences were also in nitrogen compounds content, amino acids composition and haem pigments content. Higher moisture content was often presented in game meat. Differences in protein content were not significant, but several differences were found in the protein composition. During sensory evaluation significant differences were found in intensity and pleasantness of flavour, tenderness and juiciness of meat. Further differences were also found in color.
Specific properties of game meat are transfered also to the game meat products. But in products differences are soften by the use of other components, such as other kinds of meat or food additives.
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Factors affecting food preferences of primary school pupils
Fourová, Karolína ; Kouřimská, Lenka (advisor) ; Iva, Iva (referee)
In the Czech Republic and the whole world, the global prevalence of overweight children and child obesity is increasing. This situation may result in a continuation overweight or obesity until adulthood and development related diseases, social and psychological discomfort. Overweight in children and adolescents may have a variety of negative consequences, affecting not only quality of life, but also health in adulthood. These include, for example, osteoporosis, diabetes second type, obstructive sleep apnea, hypertension, dyslipidemia or metabolic syndrome, but also the psychological aspects. Skipping breakfast or snacks and the overall low frequency of eating is often associated with high consumption of sweetened beverages and foods, high in simple sugars and a large amount of fat, which affects the development of overweight and obesity. The creation of the principles of good eating and lifestyle is depending on lifestyle of the whole family in childhood or adolescence. The environment for eating, which is created by family and school, has positive effect on promoting healthy eating and it can contribute to reducing the obesity epidemic. This study presents evidence on the level of nutrition education for elementary school pupils in the Czech Republic. Confirmation of the hypothesis, which is based on the fact, that absence of breakfast and snacks in children eating habits leads to a higher frequency of purchases of energy-dense foods with inappropriate nutritional composition, should highlight the need for increased intervention in the topic of parent's and children's eating habits. Results should support the importance of regular meals and nutritional balanced home-made snacks in children's eating habits, which could reduce the percentage of overweight and obese children and also the percentage of obese adults in future.
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