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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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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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Detection of undeclared fruit species in foodstuffs using methods of molecular biology and instrumental methods
Svobodová, Petra ; Wikarská, Monika (referee) ; Fialová, Lenka (advisor)
This thesis is focused on the detection of apple component in fruit-based baby food. The theoretical part deals with the fruit itself – the apple; food adulteration as a reason for the control of food composition and methods, both instrumental and those of molecular biology, by which food adulteration can be detected. In the experimental part, commercial products containing apple puree were purchased and model mixtures were prepared as replicas of the purchased products. DNA was isolated from these samples, its amplifiability was verified, and the presence of the apple component was detected after the selection of suitable species-specific primers. Methanol extracts for HPLC were prepared from the above-mentioned samples using a procedure previously used for the extraction of phenolic substances from apple pulp [1]. Using this analysis, apple in fruit purees was to be identified using phloridzin as a marker for the presence of the apple component. The result was a successful detection of the apple component in both commercial products and model mixtures using qPCR. However, the tested method of phenolic substance extraction proved to be unsuitable for use in the analysis of fruit purees, as phloridzin was not detected either in the apple puree extract or in the model mixtures to which this puree was added.
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Falšované potraviny a způsoby jejich detekce
Rajsiglová, Kristýna
This thesis explores the topic of food adulteration and the methods used to detect it, including the legislative requirements for different commodities. Commonly adulterated foods include meat and meat products, milk and dairy products, fats and edible oils, cocoa and chocolate, wine and spirits, honey, and coffee. Techniques such as PCR, gas and liquid chromatography, infrared and Raman spectroscopy are commonly used to detect counterfeit foods. Additionally, this paper presents the results of food adulteration detected by the State Agricultural and Food Inspection Service between 2018 and 2022. A total of 451 adulterated foods were identified, with wine, meat and meat products, and food supplements being the most frequently affected categories.
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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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|
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Detection of undeclared fruit species in foodstuffs using methods of molecular biology and instrumental methods
Svobodová, Petra ; Wikarská, Monika (referee) ; Fialová, Lenka (advisor)
This thesis is focused on the detection of apple component in fruit-based baby food. The theoretical part deals with the fruit itself – the apple; food adulteration as a reason for the control of food composition and methods, both instrumental and those of molecular biology, by which food adulteration can be detected. In the experimental part, commercial products containing apple puree were purchased and model mixtures were prepared as replicas of the purchased products. DNA was isolated from these samples, its amplifiability was verified, and the presence of the apple component was detected after the selection of suitable species-specific primers. Methanol extracts for HPLC were prepared from the above-mentioned samples using a procedure previously used for the extraction of phenolic substances from apple pulp [1]. Using this analysis, apple in fruit purees was to be identified using phloridzin as a marker for the presence of the apple component. The result was a successful detection of the apple component in both commercial products and model mixtures using qPCR. However, the tested method of phenolic substance extraction proved to be unsuitable for use in the analysis of fruit purees, as phloridzin was not detected either in the apple puree extract or in the model mixtures to which this puree was added.
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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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