Flokulacijska sposobnost kvasca Saccharomyces uvarum tijekom doviranja piva

undergraduate thesis

• Title (english): Flocculation ability of brewer's yeast Saccharomyces uvarum during the beer lagering time
• Author: Marija Krtalić
• Mentor: Sunčica Beluhan (mentor)
• Granter: University 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 country: 2010-09-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Flokulacija kvasca od davnih se dana koristi u pivovarama da bi se olakšao postupak izdvajanja biomase pivskog kvasca nakon doviranja, te je zbog toga u ovom radu proučavan mehanizam flokulacije pivskog kvasca Saccharomyces uvarum tijekom dvadeset i jednog dana doviranja piva. Uočeno je da su se stanice kvasca pojedinačno taložile na dno fermentora u prvom danu vrenja, a do kraja doviranja su se taložile u obliku manjih nakupina (agregata), čije su stanice prosječno bile veće do tri puta. Prosječan je odnos istaloženih stanica u obliku agregata rastao tijekom doviranja piva. Veličina stanica postupno je opadala sve do kraja doviranja, što je posljedica taloženja flokula kvasca. Prosječni se volumen stanica smanjio tijekom prvih 72 h doviranja piva, nakon čega se od 3-15- dana povećao. Radna kultura kvasca S. uvarum lako se taloži dodatkom Cu2+ iona, što ukazuje da je flokulacija postupak kojim se na ekonomski isplativ i prirodan način može izdvojiti biomasa kvasca u pivovarama.

Abstract (english)

Yeast flocculation has been used in the brewing industry to facilitate biomass recovery for a long time, and thus its mechanism of brewer’s yeast Saccharomyces uvarum flocculation has been studied in this work (21 days of beer lagering). It is found that yeast sedimented to the bottom of the fermentation vessel is present either as single cells (1st day of fermentation) or as small cell aggregates with a characteristic dimension of about three times that of the single cells (end of lagering). The relative proportion of the sedimented cells in aggregation form increases as fermentation proceeds. Cell size subsequently declined until the end of fermentation presumably due to floc settling. Overall yeast cell size volume initially decreased during the first 72 h of beer lagering then increased during the 3-15 days of fermentation period. The yeast strain S. uvarum was able to sediment in the presence of Cu2+ ions, which evidences that the flocculation can be used as a cheap and natural separation process for a beer production industry.

• Keywords: flokulacija; pivski kvasac; doviranje piva; Saccharomyces uvarum
• Keywords (english): flocculation; brewer’s yeast; beer lagering; Saccharomyces uvarum
• Language: croatian
• URN:NBN: urn:nbn:hr:159:944806
• Study programme: Title: 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 resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-06-07 11:24:21