Določevanje stabilnosti nekaterih polifenolnih antioksidantov

Povzetek

Ključne besede

Podatki

Jezik:	Slovenski jezik
Leto izida:	2013
Izvor:	Ljubljana
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UL PEF - Pedagoška fakulteta
Založnik:	[I. Abramović]
UDK:	54:678.048(043.2)
COBISS:	9687625
Št. ogledov:	999
Št. prenosov:	236
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Stability determination of some polyphenolic antioxidants
Sekundarni povzetek:	Polyphenolic acids form a diverse group that includes the widely distributed hydroxybenzoic and hidroxycinnamic acids. They have a carboxyl group and one or more hidroxyl groups linked to benzene ring. Because of the hidroxyl group which is linked to the aromatic ring, they act as antioxidants. In this thesis there was a study of stability of some polyphenolic antioxidants in aqueous solutions and a real sample of wine in different conditions; at low temperature, at room temperature in the absence of atmospheric oxygen and at room temperature in the presence of atmospheric oxygen. To monitor the stability of phenolic acids in aqueous solutions and real sample of wine I used high performance liquid chromatography (preliminary High Performace Liquid Chromatography, HPLC). The retention time of polyphenolic antioxidants, their surface area and peak heights were determined experimentally. From the resulting data I drew a calibration curve. From the equations of calibration curves I calculated the mass concentration of all six polyphenol antioxidants in aqueous solutions and real sample of wine at three different conditions (refrigerator, outside closed and outside open) and drew graphs: dependence of the mass concentration from time for each antioxidant in aqueous solution and the wine at all three conditions. The results showed that the antioxidants in aqueous solutions and wine were stable longer at low temperature and at room temperature in the absence of atmospheric oxygen than at room temperature in the presence of atmospheric oxygen.
Sekundarne ključne besede:	chemistry;kemija;
Vrsta datoteke:	application/pdf
Vrsta dela (COBISS):	Diplomsko delo
Komentar na gradivo:	Univ. Ljubljana, Pedagoška fak., Biotehniška fak., Fak. za kemijo in kemijsko tehnologijo, Naravoslovnotehniška fak., Kemija in biologija
Strani:	75 str.
Vrsta dela (ePrints):	thesis
Naslov (ePrints):	Stability determination of some polyphenolic antioxidants
Ključne besede (ePrints):	polifenolni antioksidanti
Ključne besede (ePrints, sekundarni jezik):	polyphenolic antioxidants
Povzetek (ePrints):	Polifenolne kisline tvorijo raznoliko skupino, ki vključuje široko razširjene hidroksibenzojske in hidorksicimetne kisline. Na benzenov obroč imajo vezano karboksilno skupino in eno ali več hidroksilnih skupin. Zaradi hidroksilne skupine, ki je vezana na aromatski obroč, se obnašajo kot antioksidanti. V diplomskem delu je bila opravljena študija obstojnosti nekaterih polifenolnih antioksidantov v vodnih raztopinah in realnem vzorcu vinu pri različnih pogojih; nizki temperaturi, sobni temperaturi v odsotnosti kisika in sobni temperaturi ob prisotnosti kisika. Za spremljanje stabilnosti fenolnih kislin v vodnih raztopinah in v realnem vzorcu vinu sem uporabila tekočinsko kromatografijo visoke ločljivosti (angl. High Performace Liquid Chromatography, HPLC). Eksperimentalno sem določila retencijske čase polifenolnih antioksidantov, njihove ploščine in višine vrhov. Iz dobljenih podatkov sem narisala umeritvene krivulje. Iz enačb umeritvenih krivulj sem izračunala masne koncentracije vseh šestih polifenolnih antioksidantov v vodnih raztopinah in v realnem vzorcu vina pri treh različnih pogojih (hladilniku, zunaj zaprto in zunaj odprto) ter narisala grafe: odvisnost masne koncentracije od časa za vsak posamezen antioksidant v vodni raztopini in v vinu pri vseh treh pogojih. Rezultati so pokazali, da so antioksidanti tako v vodnih raztopinah kot v vinu obstojni dalj časa pri nizki temperaturi in pri sobni temperaturi v odsotnosti zračnega kisika, najmanj pa so obstojni pri sobni temperaturi ob prisotnosti zračnega kisika.
Povzetek (ePrints, sekundarni jezik):	Polyphenolic acids form a diverse group that includes the widely distributed hydroxybenzoic and hidroxycinnamic acids. They have a carboxyl group and one or more hidroxyl groups linked to benzene ring. Because of the hidroxyl group which is linked to the aromatic ring, they act as antioxidants. In this thesis there was a study of stability of some polyphenolic antioxidants in aqueous solutions and a real sample of wine in different conditions; at low temperature, at room temperature in the absence of atmospheric oxygen and at room temperature in the presence of atmospheric oxygen. To monitor the stability of phenolic acids in aqueous solutions and real sample of wine I used high performance liquid chromatography (preliminary High Performace Liquid Chromatography, HPLC). The retention time of polyphenolic antioxidants, their surface area and peak heights were determined experimentally. From the resulting data I drew a calibration curve. From the equations of calibration curves I calculated the mass concentration of all six polyphenol antioxidants in aqueous solutions and real sample of wine at three different conditions (refrigerator, outside closed and outside open) and drew graphs: dependence of the mass concentration from time for each antioxidant in aqueous solution and the wine at all three conditions. The results showed that the antioxidants in aqueous solutions and wine were stable longer at low temperature and at room temperature in the absence of atmospheric oxygen than at room temperature in the presence of atmospheric oxygen.
Ključne besede (ePrints, sekundarni jezik):	polyphenolic antioxidants
ID:	8311549