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Determination of athenticity of plant foods by molecular techniques
Plášková, Anna ; Mikulíková, Renata (referee) ; Němcová, Andrea (advisor)
The aim of presented diploma thesis was to determination of authenticity of fruit baby foods for early infant feeding using molecular methods. In the experimental part, isolation kit was used for isolation of plant DNA from fruits (strawberry, apricot, raspberry, apple) and from six commercial fruit products for children. Isolated DNA was characterized and verified using PCR methods with primers specific for plant rDNA (ITS2). Specific primer pairs were designed to amplify DNA for the detection of one fruit species. Primer specificity was assessed with four fruit species. A mixture of fruit puree from the two fruits was used to determine the sensitivity of the multiplex PCR assay. Six commercial fruit products were evaluated to verify the applicability of the multiplex PCR assay. The methodology of molecular detection of fruit DNA by qPCR and multiplex qPCR (duplex) includes approaches, which enable to detect two fruits (strawberry-raspberry, apricot-apple) in one reaction and thus reduces time and money requirements.
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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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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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Determination of athenticity of plant foods by molecular techniques
Plášková, Anna ; Mikulíková, Renata (referee) ; Němcová, Andrea (advisor)
The aim of presented diploma thesis was to determination of authenticity of fruit baby foods for early infant feeding using molecular methods. In the experimental part, isolation kit was used for isolation of plant DNA from fruits (strawberry, apricot, raspberry, apple) and from six commercial fruit products for children. Isolated DNA was characterized and verified using PCR methods with primers specific for plant rDNA (ITS2). Specific primer pairs were designed to amplify DNA for the detection of one fruit species. Primer specificity was assessed with four fruit species. A mixture of fruit puree from the two fruits was used to determine the sensitivity of the multiplex PCR assay. Six commercial fruit products were evaluated to verify the applicability of the multiplex PCR assay. The methodology of molecular detection of fruit DNA by qPCR and multiplex qPCR (duplex) includes approaches, which enable to detect two fruits (strawberry-raspberry, apricot-apple) in one reaction and thus reduces time and money requirements.
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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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Detekce fytopatogenů jahodníku
MICHÁLKOVÁ, Barbora
Strawberries were tested for presence of selected phytopathogens (Agrobacterium, Rhodococcus, phytoplasmas, SMYEV, SMoV, SPV1, SCV and SCRh1) by the PCR. At the same time was researched the transmission of mentioned phytopathogens by grafting. The DNA of the strawberries with positive results was sequenced.
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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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