Priprava različnih sevov kvasovk vrste Saccharomyces cerevisiae za peko kruha

Brkopec, Meta (author), Požrl, Tomaž (mentor)

Namen diplomskega dela je bil pripraviti kvasno biomaso z uporabo treh različnih sevov kvasovke Saccharomyces cerevisiae in z analizo nastale kvasne biomase ovrednotiti tehnološke lastnosti sevov. Uporabili smo sev ZIM 2113, izoliran iz mošta Kraljevina iz vinorodnega okoliša Dolenjska, sev ZIM 3704, izoliran iz jabolčnega vina na Koroškem, ki dobro presnavlja maltozo in sev suhega komercialnega kvasa znamke Di-go. Seve smo namnožili v dveh različnih tekočih gojiščih (gojišče YPD, jabolčni sok) in med samo kultivacijo spremljali rast z merjenjem optične gostote ter izrisali rastne krivulje. Najintenzivnejšo rast smo opazili pri sevu ZIM 3704, in sicer v gojišču YPD. Tudi pri določanju števila celic kvasovk pod mikroskopom smo najvišjo vrednost na koncu kultivacije določili pri sevu ZIM 3704. Sledilo je določanje vsebnosti vode v proizvedeni kvasni biomasi s sušenjem do konstantne mase. Večjih razlik pri tej analizi med kvasno biomaso posameznih sevov nismo določili. Tehnološke lastnosti različnih sevov kvasa smo vrednotili z določanjem vzhajalnega potenciala. Z metodo merjenja časa dviganja testa smo najkrajši čas vzhajanja testa izmerili pri sevu komercialnega kvasa, pri sevih ZIM 2113 in ZIM 3704 pa sta bila izmerjena časa bistveno daljša.

• Language: Slovenian
• Keywords: pekovske kvasovke, Saccharomyces cerevisiae, sevi, kvasna biomasa, optična gostota, celična rast, vsebnost vode, vzhajalni potencial, vzhajanje, kvašeno testo, kruh
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Brkopec]
• Year: 2021
• PID: 20.500.12556/RUL-130557
• UDC: 664.654.1:582.282.23
• COBISS.SI-ID: 76340739
• Publication date in RUL: 16.09.2021

BRKOPEC, Meta, 2021, Priprava različnih sevov kvasovk vrste Saccharomyces cerevisiae za peko kruha [online]. Bachelor’s thesis. Ljubljana : M. Brkopec. [Accessed 25 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=130557

Secondary language

• Language: English
• Title: Different Saccharomyces cerevisiae yeast strains propagation for breadmaking

Abstract

The aim of this work was to produce yeast biomass using three different strains of the yeast Saccharomyces cerevisiae and to evaluate the technological properties of the strains by analysing the resulting yeast biomass. If the strains used prove to be good producers of yeast biomass, they would be used for large scale production of yeast biomass outside the laboratory. We used strain ZIM 2113 isolated from must Kraljevina from Dolenjska wine region, strain ZIM 3704 isolated from cider from Carinthia, which metabolizes maltose well and strain of commercial dry yeast of Di-go brand. The strains were propagated to the appropriate concentration in two different liquid media (YPD broth and apple juice), the growth of the cells was monitored during propagation by measuring the optical density and growth curves were obtained. The most intense growth was observed with strain ZIM 3704. Also, when the number of yeast cells was determined using a microscope, the highest value was observed for strain ZIM 3704. This was followed by determination of water content in the produced yeast biomass by drying to constant mass. No major differences were observed in the analysis of yeast biomass of each strain. The technological properties of different yeast strains were evaluated by determining the rising potential. Using the method of measuring the rising time of the dough, the shortest rising time of the dough was measured for the strain of commercial yeast; for the strains ZIM 2113 and ZIM 3704, the measured times were significantly longer.

• Keywords: baker`s yeast, Saccharomyces cerevisiae, strains, yeast biomass, optical density, cell growth, water content, rising potential, rising, leavened dough, bread