diplomsko delo
Naska Kvarantan (Author), Tatjana Košmerl (Reviewer), Lea Pogačnik (Mentor)

Abstract

V okviru diplomskega dela smo določali antioksidativno učinkovitost (AOU) in vsebnost skupnih fenolnih spojin (SFS) v črnem čaju. Ugotavljali smo, kako različni načini priprave čajev vplivajo na AOU in vsebnost SFS. Osnovno čajno infuzijo smo pripravili tako, da smo 2,0 g posameznega vzorca čaja prelili z 20 mL vodovodne vode pri 100 °C ter vzorce pustili v vodi 3 minute. Nato smo spreminjali različne parametre pri pripravi čaja ter AOU in vsebnost SFS tako pripravljenih vzorcev primerjali z osnovnimi vzorci čaja. AOU vzorcev smo določili z metodo lovljenja radikala DPPH•, vsebnost SFS pa smo določili s Folin – Ciocalteujevo metodo. Ugotovili smo, da imajo nekateri načni priprave čajnih infuzij večji vpliv na AOU in vsebnost SFS kot drugi. Določili smo, da daljši čas ekstrakcije pozitivno vpliva tako na AOU kot na vsebnost SFS čajnih infuzij. Uporaba destilirane vode ima na večino vzorcev majhen, vendar pozitiven vpliv. Dodatek mleka je imel negativen učinek tako na AOU kot na vsebnost SFS čajnih infuzij. Pri pripravi čajnih infuzij z različnimi količinami vode nismo opazili nobenega očitnega vpliva na AOU in vsebnost SFS, ki bi se ponovila pri vseh vzorcih. Glede na skupne rezultate vseh analiz pri pripravi čajnih infuzij lahko zaključimo, da vrednost AOU ter vsebnost SFS najlažje povečamo tako, da podaljšamo ekstrakcijski čas.

Keywords

antioksidanti;fenolne spojine;antioksidativna učinkovitost;črni čaj;Folin-Ciocalteu;DPPH;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [N. Kvarantan]
UDC: 663.95:547.56:66.094.3.097.8
COBISS: 5046648 Link will open in a new window
Views: 576
Downloads: 206
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Other data

Secondary language: English
Secondary title: ǂThe ǂimpact of different preparation methods of black tea infusions on the antioxidant activity and total phenolic compounds
Secondary abstract: Within this graduation thesis we determined the antioxidant capacity (AOC) and total phenolic compounds (TPC) in black tea. We have examined how different methods of preparing tea infusions affect AOC and TPC. The basic tea infusion was prepared with 2.0 g of each tea sample and 20 mL of tap water at 100 °C. We left the samples in the water for 3 minutes. We than changed the parameters of tea preparation and compared the AOC and TPC of such samples with the ones from the basic tea infusions. The AOC was determined using the DPPH• radical scavenging capacity assay and TPC were determined by the Folin – Ciocalteu method. We found out that some preparation procedures have a greater influence on the AOC and TPC than others. We determined that a longer extraction time has a positive effect on both, the AOC and TPC of a tea infusion. The use of distilled water has a small but positive effect on most of the tea samples. The addition of milk negatively affected both, the AOC and TPC. The preparation of tea infusions using different amounts of water (different tea – to – water ratio) did not show any significant effect on the AOC or TPC. Based on the overall results of all the analyses of the preparation of tea infusions, we came to the conclusion that the easiest way to increase values of AOC and TPC is by prolonging the extraction time.
Secondary keywords: antioxidants;phenolic compounds;antioxidant activity;black tea;Folin-Ciocalteu;DPPH;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages: IX, 24 f., [4] str. pril.
ID: 11132591