Određivanje fenolnih spojeva i aktivnosti enzima u bobicama bazge (Sambucus nigra L.)

master's thesis

• Title (english): Determination of phenolic content and the enzyme activity in elderberry berries (Sambucus nigra L.)
• Author: Kristina Pastorčić
• Mentor: Branka Levaj (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2005-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada bila je ispitati fizikalno-kemijski sastav (ukupna i topljiva suha tvar, pH vrijednost, ukupna kiselost, ukupni i reducirajući šećeri te saharoza), aktivnost i termostabilnost enzima polifenol oksidaze (PPO) i peroksidaze (POD), utjecaj koncentracije supstrata na PPO i POD aktivnost te fenolne spojeve (ukupne fenole, neflavonoide i flavonoide) u bobicama bazge ubranih na tri geografska područja Republike Hrvatske, tj. u okolici Zagreba, Gospića i Požege. U istim uzorcima je ispitivan utjecaj vremena skladištenja pri -20 ºC (nakon 2 i 5 mjeseci) na promjenu fenolnih spojeva (ukupni fenoli, neflavonoidi i flavonoidi) te na aktivnost enzima PPO i POD. Fenolni sastav, aktivnost enzima, termostabilnost enzima i utjecaj koncentracije supstrata određena je primjenom spektrofotometrijskih metoda. Količina ukupnih fenola i flavonoida kao i aktivnost enzima se smanjuje tijekom skladištenja pri -20 ºC, dok se količina neflavonoida povećava. Najveću termostabilnost enzimi su pokazali pri 40 ºC, dok su se pri 70 ºC potpuno inaktivirali.

Abstract (english)

The purpose of this work was to analyse physico-chemical content (dry matter, pH-value, total acidity and sugars), the activity and thermostability of polyphenol oxidase (PPO) and peroxidase (POD), effect of substrate concentration on activity of PPO i POD, and phenolic content (total phenols, flavonoides, nonflavonoides) in elderberry berries harvested on three geographic areas of Republic Croatia, around Zagreb, Gospić and Požega. In the same samples is analysed the effect of time during storage at -20 ºC (after 2 and 5 months) on change of concentration phenolic content (total phenols, flavonoides, nonflavonoides) and on the activity of polyphenol oxidase and peroxidase. Level of phenolic compound and polyphenol oxidase and peroxidase activity were determinated by spectrofotometric methods, as thermostability of these enzymes and the effect of substrate concentration. Concentration of total phenols and flavonoides, as well as activity of enzymes are decreasing during storage at -20 ºC, while concentration of nonflavonoides is increasing. The highest thermostability both enzymes had on the temperature of 40 ºC, while on the temperature of 70 ºC they were complitely inactivated.

• Keywords: bazga; fenoli; peroksidaza; polifenol oksidaza
• Keywords (english): elderberry; phenols; peroxidase; polyphenoloxidase
• Language: croatian
• URN:NBN: urn:nbn:hr:159:987674
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-11 11:33:59