Utjecaj prirodnih dodataka na bazi maslinova lista tijekom prerade maslina na kvalitativna, nutritivna i senzorna svojstva proizvedenih ulja

doctoral thesis

• Title (english): Influence of natural additives based on olive leaves during olive processing on quality, nutritional and sensory properties of produced oil
• Author: Anja Novoselić
• Mentor: Karolina Brkić Bubola (mentor)
• Committee member: Dubravka Škevin (predsjednik povjerenstva)
• Committee member: Klara Kraljić (član povjerenstva)
• Committee member: Igor Lukić (član povjerenstva)
• Committee member: Ivona Elez Garofulić (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: 2022-07-25, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 665 - Oils. Fats. Waxes. Adhesives. Gums. Resins

Abstract

Cilj ovog rada je bio istražiti mogućnosti obogaćivanja djevičanskih maslinovih ulja fenolnim i hlapljivim tvarima primjenom prirodnih dodataka na bazi maslinova lista tijekom proizvodnje. U tu svrhu ispitani su utjecaji dodatka maslinova lista i vodenih ekstrakata maslinova lista tijekom proizvodnje maslinovih ulja na sastav fenolnih i hlapljivih tvari te na sastav masnih kiselina, pigmente, voskove, etilne estere masnih kiselina i senzorna svojstva proizvedenih ulja. U istraživanju su korišteni list i plod triju sorti maslina (Buža, Istarska bjelica, Leccino). Izučavano je može li primjena navedenih dodataka smanjiti negativan učinak proizvodnih čimbenika (kasniji stupanj zrelosti maslina, produljeno trajanje skladištenja maslina i skladištenja ulja) na sastav fenolnih i hlapljivih tvari u ulju. Utjecaj dodataka na bazi maslinova lista imao je različito djelovanje na parametre kvalitete u sortnim uljima ovisno o sortimentu prerađenih plodova te o količini dodanog lišća masline i vrsti dodanog vodenog ekstrakta maslinova lista. Primjena prirodnih dodatka na bazi maslinova lista nije negativno utjecala na senzorni profil istraženih sortnih ulja, odnosno u navedenim uljima nije utvrđeno postojanje mana. Utvrđene su interakcije između faktora 'dodatak maslinova lista/vodenog ekstrakta maslinova lista' i 'vremena skladištenja plodova' u njihovom utjecaju na ukupne identificirane fenolne spojeve i na ukupne identificirane hlapljive tvari. Dodatak maslinova lista utjecao je na povećanje indeksa ekstraktabilnosti tijesta maslina te na porast prinosa ulja u industrijskim uvjetima prerade maslina i proizvodnje ulja. Dobiveni rezultati značajno doprinose znanju o mogućnostima obogaćivanja ulja prirodnim antioksidansima, što može biti iskorišteno za proizvodnju maslinovih ulja boljih nutritivnih i senzornih svojstava te produljene trajnosti.

Abstract (english)

The aim of this work was to investigate the possibilities of enrichment of virgin olive oil with phenolic and volatile compounds by applying natural additives based on olive leaf during production. For this purpose, it was investigated how the addition of olive leaf and its aqueous extracts during production affects the composition of phenolic and volatile compounds, as well as the composition of fatty acids, pigments, waxes, fatty acid ethyl esters, and sensory properties of produced oils. Olive leaves and fruits of three olive varieties were included in the research (Leccino, Istarska bjelica, Buža). It was investigated if the application of these additives can reduce the negative effect of production factors (later stages of fruit ripening, prolonged duration of olive storage and oil storage) on the composition of phenolic and volatile compounds in the oil. The influence of olive leafbased supplements had a different effect on quality parameters in varietal oils depending on the variety of processed fruits and on the amount of olive leaves added, as well as on the type of olive leaf aqueous extract added. The application of natural additives based on olive leaf did not adversely affect the sensory profile of the investigated varietal oils, that is the occurence of defects was not established. Interactions were found between the factors 'addition of olive leaf/olive leaf water extract' and 'storage time of fruits' in their influence on total phenolic compounds identified and on total volatile compounds identified. The addition of olive leaf caused an increase in olive paste extractability index and an increase in oil yield in industrial conditions of olive processing and oil production. The obtained results significantly contribute to the knowledge about the possibilities of improving oils with natural antioxidants, which could be used for the production of olive oils with better nutritional and sensory properties and extended shelf life.

• Keywords: maslinovo ulje; list masline; kontrola kvalitete; fenolni spojevi; hlapljive tvari; prinos ulja; oksidacijska stabilnost; senzorna svojstva
• Keywords (english): olive oil; olive leaf; quality control; phenolic compounds; volatile compounds; oil yield; oxidative stability; sensory attributes
• Language: croatian
• URN:NBN: urn:nbn:hr:159:441313
• Promotion: 2022
• Study programme: Title: Postgraduate PhD Study in Nutrition; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje biotehničkih znanosti, polje nutricionizam (doktor/doktorica znanosti, područje biotehničkih znanosti, polje nutricionizam)
• Type of resource: Text
• Extent: 186 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-11-10 13:46:12