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undergraduate thesis
Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca
Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. urn:nbn:hr:159:577685
Grünfeld, Petra
University of Zagreb
Faculty of Food Technology and Biotechnology
Department of Biochemical Engineering
Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology

Institutional repository: Repository of the Faculty of Food Technology and Biotechnology

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Grünfeld, P. (2019). Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca (Undergraduate thesis). Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:159:577685

Grünfeld, Petra. "Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca." Undergraduate thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. https://urn.nsk.hr/urn:nbn:hr:159:577685

Grünfeld, Petra. "Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca." Undergraduate thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. https://urn.nsk.hr/urn:nbn:hr:159:577685

Grünfeld, P. (2019). 'Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca', Undergraduate thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, accessed 12 September 2024, https://urn.nsk.hr/urn:nbn:hr:159:577685

Grünfeld P. Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca [Undergraduate thesis]. Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology; 2019 [cited 2024 September 12] Available at: https://urn.nsk.hr/urn:nbn:hr:159:577685

P. Grünfeld, "Fermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca", Undergraduate thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, Zagreb, 2019. Available at: https://urn.nsk.hr/urn:nbn:hr:159:577685

Metadata
TitleFermentacija i antimikrobna aktivnost vodenih kefirnih zrnaca
Title (english)Fermentation and antimicrobial activity of water kefir grains
AuthorPetra Grünfeld
MentorSunčica Beluhan (mentor)
GranterUniversity of Zagreb
Faculty of Food Technology and Biotechnology
(Department of Biochemical Engineering)
(Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology)
Zagreb
Defense date and country2019-06-14, Croatia
Scientific / art field,
discipline and subdiscipline		BIOTECHNICAL SCIENCES
Biotechnology
Abstract
Vodeni kefir je blago kiselo, alkoholno i voćno fermentirano piće, čija fermentacija započinje s vodenim kefirnim zrncima. Vodena kefirna zrnca sastoje se od polisaharida i sadrže mikroorganizme potrebne za fermentaciju vodenog kefira. U ovom radu, proces fermentacije vodenog kefira proveden je tijekom 12 dana kako bi se otkrila dinamika združene kulture bakterija mliječne kiseline (rod Lactobacillus), octene kiseline (rod Acetobacter) i kvasaca (vrste Saccharomyces cerevisae i Dekkera bruxellensis), kao i kinetika potrošnje supstrata i proizvodnje metabolita. Glavni supstrat, saharoza, je u potpunosti metaboliziran nakon 4 dana fermentacije, što se podudara s proizvodnjom većeg dijela polisaharida vodenih kefirnih zrnaca. Glavni metaboliti fermentacije bili su mliječna i glukonska kiselina. Octena kiselina i etanol proizvedeni su u niskim koncentracijama. Najveći dio ovih metabolita nastao je tijekom prvih 96 sati fermentacije, pri čemu se pH smanjio s 3,86 na 3,45. Antimikrobna aktivnost je testirana na bakterijama vrsteEscherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium te kvascu vrste Candida albicans. Uočena je izvrsna antimikrobna aktivnost na bakterije i kvasac, no ne i na bakteriju vrste E. coli.
Abstract (english)
Water kefir is mild sour, alcoholic, and fruity fermented beverage, of which the fermentation is started with water kefir grains. The water kefir grains consists of polysaccharides and microorganisms responsable for the water kefir fermentation. In this work, a water kefir fermentation process was followed during 12 days to unravel the symbiotic community dynamics of lactic acid bacteria (genus Lactobacillus), acetic acid bacteria (genus Acetobacter), and yeasts (species Saccharomyces cerevisiae and Dekkera bruxellensts), as well as the kinetics of of substrate consumption and metabolite production.The major substrate, sucrose, was complitely converted after 4 days of fermentation, which coincided with the production of the major part of the water kefir grain polysaccharide. The main metabolites of the fermentation were lactic and gluconic acid. Acetic acid and ethanol were produced at minor concentrations. The major part of these metabolites was produced during the 96 h of the fermentation, during which the pH decreased from 3.86 to 3.45. The antimicrobial activity was tested against bacteria Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, as well as yeast Candida albicans. Antimicrobial activities were observed in the fermented samples against the investigated bacteria strains and C. albicansbut E. coli was not inhibited.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:159:577685
Study programmeTitle: Biotechnology
Study programme type: university
Study level: undergraduate
Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
Type of resourceText
File originBorn digital
Access conditionsOpen access
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Created on2019-07-12 08:53:48