Kemijska in mikrobiološka stabilnost kvercetina v pripravku iz zavrženih luskolistov čebule

Farčnik, David (author), Poklar Ulrih, Nataša (mentor), Osojnik Črnivec, Ilja Gasan (co-mentor)

V okviru magistrskega dela smo ugotavljali vpliv različnih pogojev shranjevanja rastlinskega materiala na kemijsko in mikrobiološko stabilnost kvercetina v zmletih luskolistih rumene čebule. Proučevani rastlinski material smo zmleli in liofilizirali ter ekstrakte pridobili z ekstrakcijo s 70 vol. % etanolom. Vsebnost kvercetina v ekstraktu smo določali s tekočinsko kromatografijo visoke ločljivosti na reverzni fazi. Koncentracija kvercetina v 1 g praškastega vzorca luskolistov čebule se je v prvem preizkusu skladiščenja pri različnih pogojih gibala v razponu 1,94 - 2,99 mg/g (aritmetična sredina = 2,39 mg ± 0,26 mg). V drugem preizkusu (40 °C, nasičena zračna vlaga) se je koncentracija kvercetina gibala v območju 1,99 - 2,78 mg/g (aritmetična sredina = 2,32 mg ± 0,30 mg). V tretjem preizkusu (rastlinski material v raztopinah z različnimi vrednostmi pH) je koncentracija znašala 1,63 - 3,72 mg/g (aritmetična sredina = 2,81 mg ± 0,66 mg). Praškastemu vzorcu luskolistov čebule smo določili mikrobiološko stabilnost ter protibakterijsko in protiglivno učinkovitost. Maksimalne priporočene vrednosti števila aerobnih mezofilnih bakterij (106) so bile presežene, saj so znašale 1,34 ± 0,50 x 108. Rastlinski material bi bilo potrebno za uporabo v prehrambene namene obdelati s postopkom dekontaminacije začimb. Za dodatek hrani ali kot prehransko dopolnilo smo praškasti rastlinski material tabletirali, tablete so tehtale 298 ± 2 mg. Z dodajanjem maltodekstrina smo upočasnili razpadanje tablete.

• Language: Slovenian
• Keywords: kvercetin, čebula, luskolisti čebule, bioaktivne spojine, kvercetin, stabilnost, prehranski dodatki, protimikrobna učinkovitost
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [D. Farčnik]
• Year: 2021
• PID: 20.500.12556/RUL-131984
• UDC: 664.0:635.25:577.1:547.56
• COBISS.SI-ID: 79484163
• Publication date in RUL: 08.10.2021

Secondary language

• Language: English
• Title: Chemical and microbiological stability of quercetin in ground onion peel

Abstract

The aim of this work was to determine the impact of different storage conditions of plant material on the chemical and microbiological stability of quercetin in ground yellow onion peel. The studied plant material was ground and lyophilized, and its extracts obtained by 70 vol. % ethanol extraction. The quercetin content of the extract was determined by reverse phase high performance liquid chromatography. In the first experiment of storing under various conditions the concentration of quercetin in 1 g of powder sample of onion peel ranged from 1.94 to 2.99 mg / g (mean = 2.39 mg ± 0.25 mg). In the second experiment (40 °C, saturated humidity), the quercetin concentration ranged from 1.98 to 2.78 mg / g (mean = 2.32 mg ± 0.29 mg). In the third experiment (plant material suspended in solutions with different pH values) the concentration was 1.63 – 3.71 mg / g (mean = 2.81 mg ± 0.66 mg). Microbiological stability as well as antibacterial and antifungal activity was determined for the powder sample of the onion peel. The highest recommended values of the aerobic mesophilic bacteria (106) were exceeded to 1.34 ± 0.50 x 108. If used for food purposes, the plant material would have to be treated with selected decontamination method before use. Powdered plant material was pressed into tablets for use as a food supplement or a dietary supplement. The formed tablets weighed 298 ± 2 mg. The addition of maltodextrin delayed the disintegration of the tablet.

• Keywords: quercetin, onion, onion peel, bioactive compounds, stability, dietary supplements, antimicrobial activity