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Proteomic identification of nuts in festive cookies
Kadeřábková, Lucie ; Kučková, Štěpánka (advisor) ; Kolář, Karel (referee)
This diploma thesis is devoted to the proteomic identification of selected nuts in festive cookies. Two types of mass spectrometry were used for the nut identification; their outcomes allow for comparison and completeness of the data. The theoretical part provides a comprehensive overview of the nutritional values of nuts and the issues of food fraud and authenticity. It concludes with a didactic view and potential applications in chemistry lessons and other school subjects. The experimental part analysed eleven different nuts, submitted to high temperatures, which simulated baking and seven different types of festive cookies (six mass-produced cookies and one type of cookie with priorly unknown content of nuts). Mass spectrometry MALDI-TOF was used with subsequent evaluation using relational database system PostgreSQL to obtain characteristic m/z values for each of the eleven heat-subjected nuts. These values were then compared to the m/z values of the festive cookies to identify declared nuts and nuts used in the "unknown" sample. This identification was proved with various success rates in four of six mass-produced samples. The success rate was derived from the number of unique m/z values found in each of the nuts. The "unknown" sample was correctly identified based on the presence of one third...
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Monitoring of oxidative stability of products from shell fruits
Krňávková, Martina ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
The diploma thesis deals with the monitoring of oxidative stability of products, oils and butter, from nut fruits. The theoretical part concentrates on the topic of nut fruits, their properties, compositions which are closely related to the effects on the human health and the possibilities of technological processing. The lipid storage process, especially the most frequently occurring autooxidation reactions are described, followed by experimental part of the thesis. The changes in coconut, walnut, peanut oils and peanut butter samples are monitored during storage at 4 ° C and 20 ° C by determining the acid value, the peroxide value and the fatty acid composition by the GC-FID method. The lowest oxidation stability showed walnut oil due to the highest content of unstable polyunsaturated fatty acids – up to 88,7 %. During storage at 20 ° C there was a statistically significant increase in the content of primary oxidation products, determined as peroxide value PV = 2,55 ± 0,12 µgROOHg-1. An increase was also observed in samples of peanut butter, but it was mainly due to higher water activity, which is important for chemical reactions. The durability of this product after opening mentioned on the product label correlates with their low stability
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Protein analysis of selected nuts by mass spectrometry
Kadeřábková, Lucie ; Kučková, Štěpánka (advisor) ; Chroustová, Kateřina (referee)
This bachelor thesis investigates the possibility of differentiation of certain kinds of nuts with the help of mass spectrometry used in protein analysis. The theoretical part provides an overview of nuts - their morphology, systematics, and their nutritional value. It also reports on the benefits and risks of their consumption. The theoretical part concludes with analytic methods for protein analysis in general and touches on specific studies related to the research of nuts. The experimental part solely reflects on the protein composition of nuts. Eleven different samples of nuts were used, the specimens were very finely ground, and their proteins were broken down by the enzyme trypsin. Afterwards with the use of mass spectrometry MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight) mass spectrum of each sample was obtained. These spectra were later analysed with the use of PCA (Principal Component Analysis) to simplify them for easier comparison. The PCA based comparison was successful, therefore further evaluation was conducted. A next goal was to obtain unique m/z values for each nut that was also successful. In addition, a more specific method of mass spectrometry LC-ESI-Q-TOF (Liquid Chromatography Electrospray Ionization Quadrupole Time-of-Flight) was able to identify...
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Monitoring of oxidative stability of products from shell fruits
Krňávková, Martina ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
The diploma thesis deals with the monitoring of oxidative stability of products, oils and butter, from nut fruits. The theoretical part concentrates on the topic of nut fruits, their properties, compositions which are closely related to the effects on the human health and the possibilities of technological processing. The lipid storage process, especially the most frequently occurring autooxidation reactions are described, followed by experimental part of the thesis. The changes in coconut, walnut, peanut oils and peanut butter samples are monitored during storage at 4 ° C and 20 ° C by determining the acid value, the peroxide value and the fatty acid composition by the GC-FID method. The lowest oxidation stability showed walnut oil due to the highest content of unstable polyunsaturated fatty acids – up to 88,7 %. During storage at 20 ° C there was a statistically significant increase in the content of primary oxidation products, determined as peroxide value PV = 2,55 ± 0,12 µgROOHg-1. An increase was also observed in samples of peanut butter, but it was mainly due to higher water activity, which is important for chemical reactions. The durability of this product after opening mentioned on the product label correlates with their low stability
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