Istraživanje biopotencijala mikroorganizama izoliranih iz maginje (Arbutus Unedo L.)

master's thesis

• Title (english): Research on the biopotential of microorganisms isolated from strawberry tree fruit (Arbutus unedo L.)
• Author: Duje Glavina
• Mentor: Danijela Bursać Kovačević (mentor)
• Mentor: Deni Kostelac (pomoć pri izradi, neposredni voditelj)
• Committee member: Jadranka Frece (predsjednik povjerenstva)
• Committee member: Ksenija Markov (član povjerenstva)
• Committee member: Jasna Novak (član povjerenstva)
• 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: 2025-01-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Unatoč iznimnim senzorskim i nutritivnim karakteristikama, maginja (Arbutus unedo L.) još uvijek nije popularna širokom spektru potrošača. S ciljem iskorištavanja potencijala ovog ploda, napravljen je ovaj rad. U radu su izolirani autohtoni mikroorganizmi sa zrelog ploda maginje i istražen je njihov potencijal evaluirajući niz funkcionalnih svojstava važnih za potencijalnu primjenu u razvoju novih funkcionalnih proizvoda na bazi maginje. Izolirani mikroorganizmi s najvećom specifičnom brzinom rasta su kvasac roda Kloeckera i bakterija mliječne kiseline Lactobacillus paracasei ssp. paracasei. L. paracasei pokazuje iznimno antimikrobno djelovanje (90%) prema svim analiziranim patogenima, dok Kloeckera dobro inhibira rast L. monocytogenes (54%). Ciljanom fermentacijom maginje izoliranim kvascem i bakterijom mliječne kiseline te mjerenjem antioksidacijske aktivnosti fermenata utvrđena je izuzetna sposobnost uklanjanja 2,2-difenil-1-pikrilhidrazil slobodnih radikala (iznad 70%) nakon 48-satne fermentacije od strane većine uzoraka. Maginja i maginja fermentirana kvascem Kloeckera pokazale su visoke razine inhibicije rasta svih patogenih mikroorganizama (oko 80%), osim inhibicije rasta L. monocytogenes od strane maginje fermentirane kvascem. Također se može zaključiti antimikrobna specifičnost oba uzorka prema bakterijama naspram kvasaca.

Abstract (english)

Despite its exceptional sensory and nutritional characteristics, the strawberry tree fruit (Arbutus unedo L.) is still not popular among a wide range of consumers. To harness the potential of this fruit, this study was conducted. Indigenous microorganisms were isolated from the ripe fruit of the strawberry tree, and their potential was investigated by evaluating a series of functional properties important for potential application in the development of new functional products based on the strawberry tree fruit. The isolated microorganisms with the highest specific growth rate were yeast of the genus Kloeckera and lactic acid bacteria Lactobacillus paracasei ssp. paracasei. L. paracasei exhibited exceptional antimicrobial activity (90%) against all analyzed pathogens, while Kloeckera effectively inhibited the growth of L. monocytogenes (54%). Targeted fermentation of strawberry tree fruit with the isolated yeast and lactic acid bacteria and the measurement of the antioxidant activity of the ferments revealed an exceptional ability to scavenge 2,2-diphenyl-1-picrylhydrazyl free radicals (above 70%) after 48 hours of fermentation in most samples. The strawberry tree fruit and the fruit fermented with Kloeckera yeast showed high levels of inhibition of all pathogenic microorganisms (approximately 80%), except for the inhibition of L. monocytogenes by the yeast-fermented fruit. It can also be concluded that both samples showed antimicrobial specificity towards bacteria compared to yeasts.

• Keywords: fermentacija; maginja; kvasac; bakterija mliječne kiseline
• Keywords (english): fermentation; strawberry tree fruit; yeast; lactic acid bacteria
• Language: croatian
• URN:NBN: urn:nbn:hr:159:770752
• Study programme: Title: Food Safety Management; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane (magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-01-16 12:49:04