Flavonoidi u medu – udjel i promjene tijekom skladištenja te njihov utjecaj na antioksidacijska svojstva meda

doctoral thesis

• Title (english): Flavonoids in honey – content and changes during storage and their impact on antioxidative activity of honey
• Author: Goran Šarić; MBZ: 267903
• Mentor: Nada Vahčić (mentor); MBZ: 125475
• Committee member: Mirjana Hruškar (predsjednik povjerenstva); MBZ: 190205
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2011-04-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 638/639 - Apiculture. Keeping, breeding and management of insects and other arthropods. Hunting. Fishing. Fish breeding

Abstract

U disertaciji se pomoću HPLC tehnike odredio udjel niza flavonoida (apigenin, krizin, galangin, hesperetin, kamferol, kvercetin, luteolin, miricetin i pinocembrin) u medu te se pratila promjena njihovog udjela tijekom jednogodišnjeg skladištenja. Uz to se spektrofotometrijski odredio i udio ukupnih flavonoida u medu, udio ukupnih fenolnih spojeva modificiranom Folin-Ciocaltau metodom, sposobnost «hvatanja» slobodnih radikala DPPH (1,1- diphenyl-2-picrylhydrazyl) metodom i antioksidativni kapacitet prijenosa elektrona FRAP (Ferric Reducing Antioxidant Power) metodom. Uzorci su bili skladišteni na sobnoj temperaturi, na policama izloženim svijetlu, u prozirnim staklenim posudama. Ispitivanja su se provodila na dvije vrste meda; uniflorni – bagrem (Robinia pseudoacacia L.) i multiflorni – cvjetni, koji su porijeklom iz četiri regije s Varaždinskog područja. Ukupan broj uzoraka je bio 40 i to po 20 od svake vrste meda (5 iz svake regije). Na osnovu dobivenih rezultata odredile su se promjene udjela gore spomenutih flavonoida i posljedično tome promjene u antioksidacijskoj aktivnosti u uzorcima meda. Provedena je analiza varijance u svrhu utvrđivanja utjecaja regije, vrste meda i vremena skladištenja na različite parametre antioksidacijske aktivnosti meda te na udjele ukupnih fenola i ukupnih flavonoida. Uz to je provedena i analiza glavnih komponenata sa ciljem utvrđivanja povezanosti regije i vrste meda sa pojedinim flavonoidom, tj. da se vidi da li je neki od flavonoida specifičan za određenu vrstu meda.

Abstract (english)

In this thesis, content of some flavonoids (apigenin, chryzin, galangin, hesperetin, kaempferol, quercetin, luteolin, myricetin and pinocembrin) was determined in honey during storage in one year, by HPLC technique. Besides that, total flavonoids were determined, modified Folin-Ciocaltau method was used to determine total phenolics and DPPH (1,1-diphenyl-2-picrylhydrazyl) and FRAP (Ferric Reducing Antioxidant Power) methods was used to determine total antioxidative activity in honey. Samples were stored in room temperature, on shelves exposed to light, in transparent glass containers. Two types of honey were investigated; monofloral – acacia (Robinia pseudoacacia L.) and multifloral – floral, which come from four different subregions in Varaždin region. Total sample number was 40, 20 of each type (5 from each subregion). According to the obtained data the rate of decrease or increase in content of above mentioned flavonoids was determined and changes in antioxidative activity in honey samples were measured. Analysis of variance was made for the purpose of determining the influence of region, honey type and storage time on different parameters of antioxidative activity and on total phenolic / total flavonoid content in honey samples. Besides that, principal component analysis was conducted with the goal of determining the connection between region and honey type with individual flavonoid, i.e. to establish if a particular flavonoid is distinctive for a certain honey type.

• Keywords: antioksidacijska aktivnost; fenolni spojevi; flavonoidi; med; skladištenje
• Keywords (english): antioxidative activity; phenolic compounds; flavonoids; honey; storage
• Language: croatian
• URN:NBN: urn:nbn:hr:159:900988
• Promotion: 2011-07-03
• Study programme: Title: Nutrition; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor znanosti/doktorica znanosti (doktor znanosti/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-16 09:09:01