20.500.12556/DKUM-94966 Kinetika razpada elagitaninov diplomsko delo univerzitetnega študijskega programa I. stopnje Degradation kinetics of ellagitannins Tanini, kot je veskalagin, spadajo med zelo pomembne rastlinske metabolite, saj rastlino varujejo pred številnimi boleznimi in zajedalci. Hkrati imajo velik pomen v človeški prehrani zaradi svojih antioksidativnih in protivnetnih lastnosti. Odpornost bakterij na antibiotike dandanes predstavlja eno izmed največjih problematik, zato se v intenzivni vzreji živali h krmi namesto antibiotikov dodajajo tanini, saj imajo pomemben protibakterijski učinek. Zaradi vseh teh izjemnih lastnosti taninov smo se v diplomskem delu odločili raziskati, kako različni dejavniki vplivajo na razpad veskalagina in njegovih derivatov. V diplomskem delu smo preučevali vpliv temperature, pH-ja, inertne atmosfere in koncentracije vodikovega peroksida na razpad veskalagina in veskalina. S pomočjo HPLC-UV/DAD smo pri valovni dolžini 280 nm pomerili kromatograme vzorcev veskalagina in veskalina pri različnih časovnih intervalih. Vzorce smo prepihovali z dušikom, da smo zagotovili inertno atmosfero, in jim dodali točno določeno koncentracijo vodikovega peroksida. Eksperimentalnim podatkom smo s pomočjo programa Dynafit in programa, ki smo ga spisali v programskem jeziku Python, globalno prilegali dva teoretična modela, s čimer smo pridobili kinetične parametre. Iz rezultatov je razvidno, da veskalagin in veskalin pri višji temperaturi in pH-ju hitreje razpadata. Vidimo lahko tudi, da je razpad veskalagina in veskalina v inertni atmosferi zanemarljiv, v prisotnosti vodikovega peroksida pa oksidacija ne poteka le zaradi vodikovega peroksida, ampak ima zelo pomemben vpliv tudi avtokataliza. Model A, ki upošteva reakcijo avtokatalize, se eksperimentalnim podatkom veskalagina in veskalina odlično prilega in tudi globalno pridobljeni kinetični parametri oksidacije so med sabo v ustreznem razmerju. Tannins such as vescalagin are among the most important plant metabolites, as they protect the plant from many diseases and pests. At the same time, they are of great importance in the human diet due to their antioxidant and anti-inflammatory properties. The resistance of bacteria to antibiotics is one of the biggest problems today, which is why, in intensive animal breeding, tannins are added to the feed instead of antibiotics, as they have an important antibacterial effect. Because of all these exceptional properties of tannins, in this bachelor thesis we decided to investigate how various factors affect the degradation of vescalagin and its derivatives. In the thesis, we studied the influence of temperature, pH, inert atmosphere and hydrogen peroxide concentration on the degradation of vescalagin and vescalin. Chromatograms of samples of vescalagin and vescalin were recorded at different time intervals using HPLC-UV/DAD at the wavelenght of 280 nm. The samples were purged with nitrogen to ensure an inert atmosphere and a specific concentration of hydrogen peroxide was added. Two theoretical models were globally fitted to the experimental data using the Dynafit program and the program, written in Python programming language, thereby obtaining kinetic parameters. The results show that the degradation of vescalagin and vescalin in an inert atmosphere is negligible, and in the presence of hydrogen peroxide, oxidation is not only due to hydrogen peroxide, but autocatalysis also has a very important influence. Model A, which contains an autocatalysis element, perfectly fit the experimental data of vescalagin and vescalin, and the globally obtained oxidation kinetic parameters are also in a suitable relationship. veskalagin veskalin temperaturna stabilnost pH stabilnost HPLC modeliranje oksidacija hidroliza avtokataliza vescalagin vescalin temperature stability pH stability HPLC modeling oxidation hydrolysis autocatalysis true true false [J. Toplak] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2025-08-30 05:18:01 2025-09-09 13:00:36 2025-09-20 03:15:53 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (X, 49 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 66.092:547.98(043.2) 249591043 UN_Toplak_Jan_2025.pdf UN_Toplak_Jan_2025.pdf 1 E1DAF42DC10FC8DC2DFEF919D319A3E5 7a339de32d3fc28c04d759f6ae9d29b16a7fb07148324ca41cb927244189d8dd 6f1e570e-85e0-11f0-ad15-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=197101 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0