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The influence of polysaccharide contamination on molecular-biology analysis
Žylková, Kateřina ; Strečanská, Paulína (referee) ; Fialová, Lenka (advisor)
The presence of polysaccharides in DNA isolation and its subsequent analysis often leads to undesirable effects. Polysaccharides together with other metabolites (phenolics, proteins) can act as inhibitors of PCR. In this work, the effect of polysaccharide contamination on the analyzed DNA was investigated. In the experimental part, DNA samples were isolated from two exotic fruits (mango, banana), from which the concentration of polysaccharides was then determined. The analysis showed that by adding CaCl2, the polysaccharide content of the samples was significantly lower. After checking the amplification of the DNA samples with added CaCl2, it was found that CaCl2 itself inhibited PCR and therefore had to be removed from the samples. After purification, the amplification of the DNA was reverified and it was found that the DNA with CaCl2 after purification gave the best results. These results were further verified by agarose gel electrophoresis, which confirmed that a reduction in the polysaccharide content of the samples helped DNA amplification. It was also observed that it depends on the type of polysaccharides present in the source plant material. Banana DNA showed better amplification results than mango DNA. This is due to the different chemical composition of these fruits. Banana, unlike mango, does not contain polysaccharides that would significantly contaminate the isolated DNA.
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Fruits and vegetables as sources of fiber and minerals in the school systém.
ZDENĚK, Filip
From research on the effects of diet rich in vegetables and fruits comes convincing evidence of its benefits for human health and contribution to the prevention and fight against NCDs. Based on the knowledge about the importance of proper nutrition, efforts are being made to create suitable eating habits in children during the school attending period. The aim of this thesis is to find out whether the state of consumption of fruit and vegetables (2018-2020) in the practice of the school canteen corresponds to the nutritional standards. Another goal is to determine the average representation of fibre in one lunch among diners 7-14 years of age and to evaluate whether it corresponds to adequate intake according to EFSA. Using secondary analysis, data from collected consumption baskets at the selected school canteen were processed. Gathered values were statistically tested to evaluate the hypothesis of compliance or non-compliance with the norms.
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Development of methods for genetic analysis of plant foods
Fialová, Lenka ; Brázda, Václav (referee) ; Doškař, Jiří (referee) ; Márová, Ivana (advisor)
Multiplex real-time PCR-HRM is an approach which has gained some attention in recent years. It has already found applications in clinical diagnostics and food authenticity and safety control. Compared to its corresponding singleplex PCR assays, an optimized multiplex PCR assay provides the same information in a fraction of time. First part of this work dealt with isolation of DNA from both fresh fruits and processed commercial products. Six different DNA isolation protocols were tested with fresh fruits – three silica column-based kits, two magnetic carrier-based kits and one conventional protocol. One method was chosen as the most suitable and was applied to DNA isolation from commercial products. These experiments also involved optimisation of the chosen method. The second part of this work was focused on the development of a triplex real-time PCR assay for simultaneous detection of blueberry, strawberry and raspberry, and its application on DNA isolated from commercial products. During DNA isolation, calcium chloride was shown to be a promising agent for removal of pectin from samples. In several samples, presence of raspberry DNA was confirmed by singleplex PCR. We found out that for accurate results of food analysis by this assay, further optimization of its parameters would be needed.
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Influence of matrix type on the authentication of foodstuffs containing fruits
Kopková, Pavlína ; Strečanská, Paulína (referee) ; Fialová, Lenka (advisor)
Certain types of food, mainly the more expensive ones, are often adulterated to reduce their manufacturing price. However, this reduces their quality and can also have a negative impact on the health of the consumer. Children's fruit products are also targeted by fraudulent producers, where the declared fruit is most often replaced by a cheaper version. This work focuses on the detection of adulterated foods using various analytical methods, in particular PCR. The theoretical part focuses on the issue of food adulteration, the analytical methods used for detecting adulteration, and also on mango and banana which are determined in this work. The aim of this thesis was to determine what effect the type of matrix has on the determination of fruit components in food by PCR. Three types of matrix were used for this purpose - fruit puree, smoothie, and bars. An important task was to optimize the DNA isolation to achieve adequate purity and concentration of DNA. Then, the amplifiability of the obtained DNA was verified. The DNA isolates were then analyzed by multiplex PCR with primers specific for mango and banana. The results were verified by agarose gel electrophoresis. Subsequently, it was possible to determine that the fruit component in bars and fresh smoothies was the most easily analyzed by PCR and, on the contrary, the determination was problematic for puree. The instrumental part was focused on the determination of phenolic compounds in the products by HPLC. For this purpose, optimization of the extraction of phenolic compounds was necessary. This method was able to detect the presence of mangoes in all samples.
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Fruit and vegetable intake and self-rated health in the Czech republic: the HAPIEE study
Hrežová, Eliška ; Pikhart, Hynek (advisor) ; Lustigová, Michala (referee)
This thesis deals with self-rated health and consumption of fruits and vegetables in the Czech part of the HAPIEE study. The recommended amount of 400 g of fruit and vegetable consumption was met at 49,2% of men and 70,1% of women participating in the study. In the case of a higher 600 g recommendation it was 23,3% men and 42,6% women. The relationship between self-rated health and fruit and vegetable consumption was analyzed using the logistic regression method. Health was better assessed by those who consumed fruits and vegetables in the interval of 258-549g (2nd and 3rd quintiles of fruit and vegetable consumption). Those who consumed less or more fruits and vegetables rated their health worse. There were no differences in the relationship between self-rated health and consumption of fruits and vegetables among the sexes, although men had a higher chance of rating their health as bad than women. Key words: self rated health, fruit and vegetable intake, fruit, vegetable, regression
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Detection of selected fruit species in plant-based foodstuffs through instrumental analysis and methods of molecular biology
Ondruch, Petr ; Langová, Denisa (referee) ; Fialová, Lenka (advisor)
Food is often subject to adulteration, including fruit products containing strawberries. This work deals with the detection of strawberries in model and real fruit products, so that possible falsification can be detected. The aim of the work was the preparation of model and real fruit products, their analysis using selected instrumental and molecular-biological methods and mutual comparison of the results of these methods. Model mixtures of fruit products were prepared and commercial ones were purchased. The content of polyphenols and flavonoids was determined by UV-VIS spectrophotometry, which were characterized in more detail by HPLC. DNA was isolated from the fruit purees, suitable primers confirmed the amplifiability and formation of a specific product for strawberry, and this product was verified by electrophoretic control. In the instrumental part, certain substances were detected by extraction from model and commercial mixtures and the HPLC method, and the amount of selected substances was determined. The lowest amount of strawberry DNA that could be detected by selected primers in the PCR method was 0.7 ng /µl, in commercial mixtures this DNA could not be detected. In the HPLC method, the strawberry was detected in all samples by focusing on a particular fingerprint and the amount of pelargonidin-3-glucoside in the samples. The instrumental method can be considered more suitable in this case.
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Kvalita ovocných moštů a burčáku
Švestka, Michal
The aim of this bachelor thesis is to inform about fruit raw juices with a main focus on apple raw juice and partially fermented grape raw juice in our country called - burčák. The thesis gives attention on the basic data about fruit orchards and vineyards planted in the Czech Republic and their varietal composition. It focuses on the input raw material and its composition. The next chapter describes the technology of the production of raw juices and partially fermented grape raw juice and the subsequent conservation possibilities. The thesis also focuses on the quality of raw juices marketed on the domestic market and the statistics of the checks of the burčák made by the State Agriculture and Food Inspection. The conclusion of the thesis informs about the influence and benefit of these beverages on human health.
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Mikrobiologické parametry výroby, skladování a distribuce raw potravin
Vávra, Jaroslav
Bachelor thesis Microbiological parameters of production, storage and distribution of raw food includes theoretical and practical part. Literary research is a compilation of public and expert attitudes to raw foods, legislative regulations for used raw materials and food for immediate consumption, basics of production technology, knowledge of microbes, their metabolism products and possible health risks associated with them. The experiment was a basic microbiological analysis of raw bar samples to determine the total number of microorganisms, fungi and yeasts, coliforms, and the presence of Eschericia coli. The gained results of the experiment were subsequently compared with legislative regulations, especially with the norm ČSN 56 9609. The last part of the experiment was a short rough sensory evaluation. Although many microorganisms have been found in the products, there hasn‘t been over limit.
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