Določevanje stabilnosti nekaterih polifenolnih antioksidantov

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Language:	Slovenian
Year of publishing:	2013
Source:	Ljubljana
Typology:	2.11 - Undergraduate Thesis
Organization:	UL PEF - Faculty of Education
Publisher:	[I. Abramović]
UDC:	54:678.048(043.2)
COBISS:	9687625
Views:	999
Downloads:	236
Average score:	0 (0 votes)
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Secondary language:	English
Secondary title:	Stability determination of some polyphenolic antioxidants
Secondary abstract:	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.
Secondary keywords:	chemistry;kemija;
File type:	application/pdf
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. Ljubljana, Pedagoška fak., Biotehniška fak., Fak. za kemijo in kemijsko tehnologijo, Naravoslovnotehniška fak., Kemija in biologija
Pages:	75 str.
Type (ePrints):	thesis
Title (ePrints):	Stability determination of some polyphenolic antioxidants
Keywords (ePrints):	polifenolni antioksidanti
Keywords (ePrints, secondary language):	polyphenolic antioxidants
Abstract (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.
Abstract (ePrints, secondary language):	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.
Keywords (ePrints, secondary language):	polyphenolic antioxidants
ID:	8311549