Utjecaj indeksa zrelosti na aktivnost endogenih enzima hrvatskih autohtonih sorti maslina

master's thesis

• Title (english): The effect of maturity index on the activity of endogenous enzymes of croatian autochthonous olive varieties
• Author: Nika Butula
• Mentor: Klara Kraljić (mentor)
• Mentor: Katarina Filipan (pomoć pri izradi, neposredni voditelj)
• Committee member: Dubravka Škevin (predsjednik povjerenstva)
• Committee member: Igor Stuparević (član povjerenstva)
• Committee member: Sandra Balbino (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Oil and Fat Technology); Zagreb
• Defense date and country: 2023-03-31, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Endogeni enzimi u plodovima maslina i biokemijske transformacije koje oni kataliziraju definiraju nutritivnu vrijednost i senzorske karakteristike djevičanskog maslinovog ulja. U ovom radu je njihova aktivnost ispitivana u plodovima hrvatskih autohtonih sorti, oblici, levantinki, istarskoj bjelici i rosulji u tri stupnja zrelosti. Cilj ovog rada je bio definirati utjecaj indeksa zrelosti i sorte na aktivnost endogenih enzima. β-glukozidaza, polifenol oksidaza i peroksidaza su izolirani iz acetonskih prahova a aktivnost im je određena spektrofotometrijski, dok je lipoksigenaza izolirana iz smrznutog tijesta, a aktivnost određena HPLC metodom. Aktivnost β-glukozidaze nije detektirana zbog čega nije bilo moguće utvrditi utjecaj istraživanih parametara na njezinu aktivnost. Aktivnost peroksidaze u svim je sortama izrazito niska i raste s povećanjem indeksa zrelosti. Aktivnosti polifenol oksidaze i lipoksigenaze pokazala se kao sortna karakteristika jer su trendovi aktivnosti tih enzima različiti u svim sortama.

Abstract (english)

The endogenous enzymes in olive fruit and the transformations they catalyze determine the nutritional value and sensory properties of virgin olive oil. In this study, their activity was investigated in fruits of Croatian autochthonous olive varieties Oblica, Levantinka, Istrian Bjelica and Rosulja at three stages of ripening. The aim of this study was to determine the influence of the maturity index and variety on the activity of endogenous olive enzymes. β-glucosidase, polyphenol oxidase and peroxidase were isolated from acetone powders and their activity was determined spectrophotometrically, while lipoxygenase was isolated from frozen olive paste, and its activity was determined by HPLC method. The activity of βglucosidase was not detected, therefore it was not possible to determine the effect of the investigated parameters on its activity. Peroxidase activity was low in all samples studied and increased with increasing maturity index. The activity of polyphenol oxidase and lipoxygenase proved to be a varietal characteristic of olives, since the trends of the activity of these enzymes were different among the studied varieties.

• Keywords: aktivnost endogenih enzima; hrvatske autohtone sorte maslina; indeks zrelosti
• Keywords (english): activity of endogenous enzymes; Croatian autochthonous olive varieties; maturity index
• Language: croatian
• URN:NBN: urn:nbn:hr:159:792074
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-05-21 08:56:33