Hidrotermična degradacija ekstrakta čebule - vpliv koncentracije

diplomsko delo univerzitetnega študijskega programa I. stopnje

Nina Žunko (Author), Mojca Škerget (Mentor), Željko Knez (Co-mentor)

Abstract

Namen tega diplomskega dela je bil izvesti hidrolizo ekstrakta čebulnih olupkov s pomočjo reaktivne subkritične vode. Čebulni ekstrakt je kompleksen matriks različnih spojin, predvsem kvercetina ter tudi različnih ogljikovih hidratov in proantocianidinov. Kvercetin v naravi običajno ni prisoten v svoji prosti obliki, ampak je najpogosteje vezan s sladkorji v t. i. glikozide. Koncentracija raztopine oziroma razmerje material : voda je procesni parameter, ki je pri mnogih študijah razgradnje s subkritično vodo pogosto ignoriran. Zato je bil cilj diplomskega dela preučiti vpliv koncentracije vodne raztopine ekstrakta čebule na nastanek prostega aglikona. Temperaturo in tlak smo pri tem vzdrževali konstantna (200 °C, 200 bar). Preučili smo tudi vpliv koncentracije vodne raztopine ekstrakta na nastanek drugih, predvsem razgradnih produktov kvercetina. V prvem delu smo izvedli ekstrakcijo čebulnih olupkov s konvencionalnim ekstrakcijskim postopkom. Ekstrakt smo v drugem delu uporabili za hidrotermične poskuse razgradnje v laboratorijskem visokotlačnem visokotemperaturnem avtoklavu (Andreas Hofer Hochdrucktechnik) pri subkritičnih pogojih vode in v prisotnosti plina CO2 za vzdrževanje tlaka v reaktorju. Dobljene vzorce smo analizirali z metodo HPLC (tekočinska kromatografija visoke ločljivosti) na sistemu Agilent 1100. Na podlagi rezultatov smo ugotovili, da je kinetika razgradnje kvercetina neodvisna od koncentracije.

Keywords

subkritična voda;hidrotermična degradacija;kvercetin;konvencionalna ekstrakcija;HPLC;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2017
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[N. Žunko]
UDC:	66.094.941:547.918(043.2)
COBISS:	20443414
Views:	1062
Downloads:	102
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	HYDROTHERMAL DEGRADATION OF ONION EXTRACT - INFLUENCE OF CONCENTRATION
Secondary abstract:	The purpose of this graduate thesis was to carry out the hydrolysis of an extract of onion peels using reactive subcritical water. Onion extract is a complex matrix of various compounds, in particular quercetin, and also a variety of carbohydrates and proanthocyanidins. Quercetin is usually not present in nature in its free form but is most commonly bonded to sugars in glicosides. Concentration of water solution or water to material ratio is a process parameter which in many studies of degradation with subcritical water often remains ignored. Therefore, the aim of the thesis was to examine the impact of the concentration of water solution of onion peel extract on the formation of free aglycone. The temperature and pressure were kept constant (200°C, 200 bar). We also studied the impact of concentration of water solution on the formation of main quercetin metabolites. In the first part, we performed extraction of onion peels with conventional extraction process. In the second part of the hydrothermal experiments of degradation the extract was treated in a laboratory high-pressure high-temperature autoclave (Andreas Hofer Hochdrucktechnik) in subcritical water with presence of CO2, used for maintaining constant pressure in the reactor. The resulting samples were analyzed by HPLC (high performance liquid chromatography) on an Agilent 1100 system. Based on the results, we found that the kinetics of quercetin degradation is not dependent on concentration.
Secondary keywords:	subcritical water;hydrothermal degradation;quercetin;conventional extraction;HPLC;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	X, 35 str.
ID:	9166058